libc: Implement setjmp() and longjmp()

Now, fork() and exec() are both implemented. More POSIX-y, thus spawn can be removed.

.gitignore

@@ -7,6 +7,7 @@ kernel/bin/moon.elf
 initrd/sys/moon.sym
 initrd/bin/**
 apps/bin/**
+tests/**/bin/**
 base/usr/include/**
 base/usr/lib/**
 **/*.a

README.md

@@ -6,11 +6,12 @@ Not so much at the moment.
 
 - x86_64-compatible [kernel](kernel/).
 - Keeps track of which [memory](kernel/src/memory/) is used and which memory is free, and can allocate memory for itself and [user programs](kernel/src/sys/mem.cpp).
-- Can [load files](kernel/src/fs/) from an [initial ramdisk](initrd/), no disk support yet.
+- Can load files from a [virtual file system](kernel/src/fs/) supporting an initial ramdisk, device pseudo-filesystems... but no hard disks yet.
 - Basic preemptive multitasking, round-robin [scheduler](kernel/src/thread/) that can switch between tasks.
-- Can [load userspace ELF programs](kernel/src/sys/elf/) from the initial ramdisk as user tasks.
+- Can [load userspace ELF programs](kernel/src/sys/elf/) from the file system as user tasks.
-- [System call](kernel/src/sys/) interface and bare-bones [C Library](libs/libc/).
+- [System call](kernel/src/sys/) interface and simple [C Library](libs/libc/), aiming to be POSIX-compatible.
-- Some very simple [example programs](apps/), written in C, that the kernel then loads from the initial ramdisk.
+- Some very simple [example programs](apps/), written in C, that then can get loaded and executed by the kernel.
+- UNIX-like [multitasking primitives](kernel/src/sys/exec.cpp), which allow user tasks to spawn other tasks.
 
 ## Setup
 To build and run Luna, you will need to build a [GCC Cross-Compiler](https://wiki.osdev.org/Why_do_I_need_a_Cross_Compiler%3F) and cross-binutils for `x86_64-luna`. (Yes, Luna is advanced enough that it can use its own [OS-Specific Toolchain](https://wiki.osdev.org/OS_Specific_Toolchain), instead of a bare metal target like `x86_64-elf`. It is the first of my OS projects to be able to do so. The patches for Binutils and GCC are [binutils.patch](tools/binutils.patch) and [gcc.patch](tools/gcc.patch)).

apps/Makefile

@@ -11,7 +11,6 @@ CFLAGS := -Wall -Wextra -Werror -Os
 $(APPS_BIN)/%: $(APPS_SRC)/%.c
 	@mkdir -p $(@D)
 	$(CC) $(CFLAGS) -o $@ $^
-	$(STRIP) $@
 
 build: $(REAL_APPS)
 

apps/src/init.c

@@ -1,26 +1,24 @@
-#include <errno.h>
 #include <luna.h>
+#include <setjmp.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/syscall.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
-typedef long ssize_t;
-
 int print_version()
 {
     char version[4096];
 
-    FILE* verfile = fopen("/dev/version", "r");
+    FILE* fp = fopen("/dev/version", "r");
-    if (!verfile)
+    if (!fp)
     {
         perror("fopen");
         return 1;
     }
 
-    size_t nread = fread(version, 4096, 1, verfile);
+    size_t nread = fread(version, 4096, 1, fp);
-    if (ferror(verfile))
+    if (ferror(fp))
     {
         perror("fread");
         return 1;
@@ -28,7 +26,7 @@ int print_version()
 
     version[nread] = 0;
 
-    if (fclose(verfile) < 0)
+    if (fclose(fp) < 0)
     {
         perror("fclose");
         return 1;
@@ -41,9 +39,9 @@ int print_version()
 
 int main()
 {
-    if (gettid() == 0) // why are we the idle task?
+    if (getpid() != 1)
     {
-        fprintf(stderr, "SHENANIGANS! init is tid 0 (which is reserved for the idle task)\n");
+        fprintf(stderr, "init should be started as PID 1\n");
         return 1;
     }
 
@@ -66,7 +64,7 @@ int main()
 
     printf("Welcome to Luna!\n");
 
-    printf("Running as tid %ld\n\n", gettid());
+    printf("Running as PID %ld\n\n", getpid());
 
     sleep(1);
 
@@ -117,9 +115,69 @@ int main()
 
     if (fclose(config) < 0) { perror("fclose"); }
 
+    printf("\n\nGot random number %d\n\n", rand());
+
     sleep(2);
 
-    printf("\n\nPress any key to restart.\n\n");
+    printf("Press any key to restart.\n\n");
 
-    return 0;
+    int stderr_fd = fileno(stderr);
+    int new_stderr_fd = dup(stderr_fd);
+    if (new_stderr_fd < 0)
+    {
+        perror("dup");
+        return 1;
+    }
+    FILE* new_stderr = fdopen(new_stderr_fd, "rw");
+    if (!new_stderr)
+    {
+        perror("fdopen");
+        return 1;
+    }
+
+    fprintf(new_stderr, "Bye!\n\n");
+
+    fclose(new_stderr);
+
+    const char* pathname = "/etc";
+
+    printf("Creating directory %s\n", pathname);
+
+    if (mkdir(pathname, 0) < 0)
+    {
+        perror("mkdir");
+        return 1;
+    }
+
+    printf("Success!!\n");
+
+    printf("Forking...\n");
+
+    pid_t child = fork();
+
+    if (child < 0)
+    {
+        perror("fork");
+        return 1;
+    }
+    if (child == 0)
+    {
+        msleep(500);
+        printf("I am the child, who is my parent?\n");
+        execv("/bin/sym", NULL);
+        perror("execv");
+        return 1;
+    }
+    else { printf("Success!! Got PID %ld\n", child); }
+
+    jmp_buf env;
+    int val = setjmp(env);
+    if (val == 0) { printf("Returning from setjmp!\n"); }
+    else
+    {
+        printf("Returning from longjmp! val=%d\n", val);
+        return 0;
+    }
+
+    longjmp(env, 3);
 }

apps/src/sym.c

@@ -4,7 +4,7 @@
 
 int main()
 {
-    sleep(6);
+    sleep(2);
 
     FILE* syms = fopen("/sys/moon.sym", "r");
     if (!syms)
@@ -13,15 +13,15 @@ int main()
         return 1;
     }
 
-    char buf[1025];
+    char buf[1200];
 
-    if (fseek(syms, 8000, SEEK_SET) < 0)
+    if (fseek(syms, -1199, SEEK_END) < 0)
     {
         perror("fseek");
         return 1;
     }
 
-    size_t nread = fread(buf, 1024, 1, syms);
+    size_t nread = fread(buf, 1199, 1, syms);
     if (ferror(syms))
     {
         perror("fread");

kernel/include/assert.h

@@ -1,39 +0,0 @@
-#pragma once
-#include "log/Log.h"
-#include "misc/hang.h"
-#include "thread/Scheduler.h"
-#include "trace/StackTracer.h"
-
-#define __call_assert_fail(...)                                                                                        \
-    kerrorln(__VA_ARGS__);                                                                                             \
-    StackTracer tracer;                                                                                                \
-    tracer.trace();                                                                                                    \
-    hang();
-
-#define ASSERT(expr)                                                                                                   \
-    do {                                                                                                               \
-        if (!(expr))                                                                                                   \
-        {                                                                                                              \
-            Task* cur_task = Scheduler::current_task();                                                                \
-            if (cur_task)                                                                                              \
-            {                                                                                                          \
-                __call_assert_fail("Assertion failed in task %ld at %s, line %d: %s", cur_task->id, __FILE__,          \
-                                   __LINE__, #expr);                                                                   \
-            }                                                                                                          \
-            else { __call_assert_fail("Assertion failed at %s, line %d: %s", __FILE__, __LINE__, #expr); }             \
-        }                                                                                                              \
-    } while (0)
-
-#define TODO(message)                                                                                                  \
-    do {                                                                                                               \
-        Task* cur_task = Scheduler::current_task();                                                                    \
-        if (cur_task)                                                                                                  \
-        {                                                                                                              \
-            __call_assert_fail("TODO in task %ld at %s, line %d: %s", cur_task->id, __FILE__, __LINE__, message);      \
-        }                                                                                                              \
-        else { __call_assert_fail("TODO at %s, line %d: %s", __FILE__, __LINE__, message); }                           \
-    } while (0)
-
-#ifdef ___weird_hack_to_put_something_at_end_of_file
-#undef ___weird_hack_to_put_something_at_end_of_file
-#endif

kernel/include/errno.h

@@ -6,7 +6,11 @@
 #define EBADF 9
 #define ENOMEM 12
 #define EFAULT 14
+#define EEXIST 17
+#define ENOTDIR 20
 #define EISDIR 21
 #define EINVAL 22
 #define EMFILE 24
-#define ENOSYS 38
+#define ENOSPC 28
+#define ENOSYS 38
+#define ENOTSUP 95

kernel/include/fs/FileDescriptor.h

@@ -43,6 +43,8 @@ struct Descriptor
     Descriptor(const Descriptor& other);
     Descriptor();
 
+    const Descriptor& operator=(const Descriptor& other);
+
   private:
     bool m_is_open;
     bool m_can_read;

kernel/include/fs/VFS.h

@@ -35,12 +35,15 @@ namespace VFS
 
     ssize_t read(Node* node, size_t offset, size_t length, char* buffer);
     ssize_t write(Node* node, size_t offset, size_t length, const char* buffer);
-    int mkdir(const char* path, const char* name); // FIXME: Support deducing this via a single path.
+    int mkdir(const char* path, const char* name);
+    int mkdir(const char* pathname);
 
     void mount_root(Node* root);
 
     Node* resolve_path(const char* filename, Node* root = nullptr);
 
+    bool exists(const char* pathname);
+
     void mount(Node* mountpoint, Node* mounted);
     void mount(const char* pathname, Node* mounted);
 

kernel/include/fs/devices/Random.h

@@ -0,0 +1,9 @@
+#pragma once
+#include "fs/VFS.h"
+
+namespace RandomDevice
+{
+    VFS::Node* create_new(const char* devname);
+
+    ssize_t read(VFS::Node* node, size_t offset, size_t size, char* buffer);
+}

kernel/include/kassert.h

@@ -0,0 +1,6 @@
+#pragma once
+#include "panic/Panic.h"
+
+#define ASSERT(expr) (bool)(expr) || panic("Assertion failed: " #expr)
+
+#define TODO(message) panic("TODO: " message)

kernel/include/log/Log.h

@@ -22,6 +22,7 @@ namespace KernelLog
     void logln(const char* function, LogLevel level, const char* message, ...) PRINTF_LIKE(3, 4);
     void toggle_log_level(LogLevel level);
     void toggle_log_backend(Backend backend);
+    void enable_log_backend(Backend backend);
 }
 
 #ifndef MODULE

kernel/include/memory/AddressSpace.h

@@ -7,7 +7,7 @@ struct AddressSpace
 
     void destroy();
 
-    void detach();
+    void clear();
 
     AddressSpace clone();
 
@@ -16,12 +16,6 @@ struct AddressSpace
         return m_pml4;
     }
 
-    bool is_cloned()
-    {
-        return m_cloned;
-    }
-
   private:
     PageTable* m_pml4;
-    bool m_cloned;
 };

kernel/include/memory/UserHeap.h

@@ -0,0 +1,27 @@
+#pragma once
+#include <stdint.h>
+
+struct UserHeap
+{
+    bool init();
+
+    uint64_t request_virtual_page();
+    uint64_t request_virtual_pages(uint64_t count);
+
+    void free_virtual_page(uint64_t address);
+    void free_virtual_pages(uint64_t address, uint64_t count);
+
+    void free();
+
+    bool inherit(UserHeap& other);
+
+  private:
+    uint8_t* bitmap = nullptr;
+    uint64_t bitmap_size = 0;
+    uint64_t start_index = 0;
+    bool bitmap_read(uint64_t index);
+    void bitmap_set(uint64_t index, bool value);
+
+    bool try_expand();
+    bool try_expand_size(uint64_t size);
+};

kernel/include/panic/Panic.h

@@ -5,13 +5,11 @@
 extern "C"
 {
 #endif
-    [[noreturn]] void __do_int_panic(Context* context, const char* file, int line, const char* message);
+    [[noreturn]] bool __do_int_panic(Context* context, const char* file, int line, const char* message);
-    [[noreturn]] void __do_panic(Context* context, const char* message);
+    [[noreturn]] bool __do_panic(const char* file, int line, const char* message);
-
-    [[noreturn]] void __panic(const char* message);
 #ifdef __cplusplus
 }
 #endif
 
-#define panic(message) asm volatile("cli\npush $16\npushq %%rsp\npushfq\npush $8\ncall __panic" : : "D"(message))
+#define panic(message) __do_panic(__FILE__, __LINE__, message)
 #define int_panic(context, message) __do_int_panic(context, __FILE__, __LINE__, message)

kernel/include/std/libgen.h

@@ -0,0 +1,4 @@
+#pragma once
+
+char* basename(char* path);
+char* dirname(char* path);

kernel/include/std/string.h

@@ -8,6 +8,7 @@ __attribute__((deprecated)) int strcmp(const char* a, const char* b);
 __attribute__((deprecated)) char* strcat(char* dest, const char* src);
 
 char* strncpy(char* dest, const char* src, size_t n);
+size_t strlcpy(char* dest, const char* src, size_t size);
 int strncmp(const char* a, const char* b, size_t n);
 char* strncat(char* dest, const char* src, size_t n);
 
@@ -18,4 +19,5 @@ void* memset(void* dest, int c, size_t n);
 int memcmp(const void* a, const void* b, size_t n);
 void* memmove(void* dest, void* src, size_t n);
 
-char* strdup(const char* src);
+char* strdup(const char* src);
+char* strrchr(const char* str, int c);

kernel/include/sys/Syscall.h

@@ -7,15 +7,19 @@
 #define SYS_sleep 2
 #define SYS_write 3
 #define SYS_paint 4
-#define SYS_rand 5
+#define SYS_getpid 5
-#define SYS_gettid 6
+#define SYS_mmap 6
-#define SYS_mmap 7
+#define SYS_munmap 7
-#define SYS_munmap 8
+#define SYS_open 8
-#define SYS_open 9
+#define SYS_read 9
-#define SYS_read 10
+#define SYS_close 10
-#define SYS_close 11
+#define SYS_seek 11
-#define SYS_seek 12
+#define SYS_exec 12
-#define SYS_exec 13
+#define SYS_fcntl 13
+#define SYS_mprotect 14
+#define SYS_clock 15
+#define SYS_mkdir 16
+#define SYS_fork 17
 
 namespace Syscall
 {
@@ -29,12 +33,16 @@ void sys_yield(Context* context);
 void sys_sleep(Context* context, uint64_t ms);
 void sys_write(Context* context, int fd, size_t size, const char* addr);
 void sys_paint(Context* context, uint64_t x, uint64_t y, uint64_t w, uint64_t h, uint64_t col);
-void sys_rand(Context* context);
+void sys_getpid(Context* context);
-void sys_gettid(Context* context);
+void sys_mmap(Context* context, void* address, size_t size, int prot);
-void sys_mmap(Context* context, void* address, size_t size, int flags);
 void sys_munmap(Context* context, void* address, size_t size);
 void sys_open(Context* context, const char* filename, int flags);
 void sys_read(Context* context, int fd, size_t size, char* buffer);
 void sys_close(Context* context, int fd);
 void sys_seek(Context* context, int fd, long offset, int whence);
-void sys_exec(Context* context, const char* pathname);
+void sys_exec(Context* context, const char* pathname);
+void sys_fcntl(Context* context, int fd, int command, uintptr_t arg);
+void sys_mprotect(Context* context, void* address, size_t size, int prot);
+void sys_clock(Context* context);
+void sys_mkdir(Context* context, const char* filename);
+void sys_fork(Context* context);

kernel/include/thread/Scheduler.h

@@ -9,11 +9,11 @@ namespace Scheduler
     void yield();
     void exit(int status);
     void sleep(unsigned long ms);
-    void add_kernel_task(void (*task)(void));
+    void add_kernel_task(const char* taskname, void (*task)(void));
 
     Task* create_user_task();
 
-    void load_user_task(const char* filename);
+    long load_user_task(const char* filename);
 
     void task_exit(Context* context, int64_t status);
     void task_misbehave(Context* context, int64_t status);
@@ -27,4 +27,8 @@ namespace Scheduler
     void reap_tasks();
 
     void reset_task(Task* task, ELFImage* new_image);
+
+    void append_task(Task* task);
+
+    Task* find_by_pid(uint64_t pid);
 }

kernel/include/thread/Task.h

@@ -2,9 +2,10 @@
 #include "fs/FileDescriptor.h"
 #include "interrupts/Context.h"
 #include "memory/AddressSpace.h"
+#include "memory/UserHeap.h"
 #include "sys/elf/Image.h"
 
-#define TASK_MAX_FDS 8
+#define TASK_MAX_FDS 32
 
 struct Task
 {
@@ -46,10 +47,22 @@ struct Task
     Descriptor files[TASK_MAX_FDS];
 
     AddressSpace address_space;
-};
 
-void set_context_from_task(Task& task, Context* ctx);
+    UserHeap allocator;
-void get_context_to_task(Task& task, Context* ctx);
 
-void task_save_floating(Task& task);
+    int alloc_fd();
-void task_restore_floating(Task& task);
+
+    int alloc_fd_greater_than_or_equal(int base_fd);
+
+    void save_context(Context* context);
+    void restore_context(Context* context);
+
+    void save_floating();
+    void restore_floating();
+
+    void switch_to_address_space();
+
+    bool has_died();
+
+    char name[128];
+};

kernel/include/trace/Resolve.h

@@ -1,4 +1,5 @@
 #pragma once
+#include <stddef.h>
 #include <stdint.h>
 
-void get_symbol_name(uintptr_t address, char* buffer);
+void get_symbol_name(uintptr_t address, char* buffer, size_t size);

kernel/src/fs/FileDescriptor.cpp

@@ -40,4 +40,14 @@ int Descriptor::seek(long offset)
         return -EINVAL; // FIXME: Support seeking beyond the current file's length.
     m_offset = (uint64_t)offset;
     return 0;
+}
+
+const Descriptor& Descriptor::operator=(const Descriptor& other)
+{
+    m_is_open = other.m_is_open;
+    m_can_read = other.m_can_read;
+    m_can_write = other.m_can_write;
+    m_offset = other.m_offset;
+    m_node = other.m_node;
+    return other;
 }

kernel/src/fs/VFS.cpp

@@ -3,6 +3,7 @@
 #include "fs/VFS.h"
 #include "errno.h"
 #include "log/Log.h"
+#include "std/libgen.h"
 #include "std/stdlib.h"
 #include "std/string.h"
 
@@ -131,16 +132,54 @@ int VFS::mkdir(const char* path, const char* name)
     if (!node)
     {
         kwarnln("Attempting to mkdir in %s, which does not exist", path);
-        return -1;
+        return -ENOENT;
+    }
+    if (node->type != VFS_DIRECTORY)
+    {
+        kwarnln("Attempting to mkdir in %s, which is not a directory!!", path);
+        return -ENOTDIR;
     }
     if (!node->mkdir_func)
     {
         kwarnln("Chosen node does not support mkdir()");
-        return -1;
+        return -ENOTSUP;
+    }
+    if (!node->find_func)
+    {
+        kwarnln("Chosen node does not support finddir()");
+        return -ENOTSUP;
+    }
+    if (node->find_func(node, name) != nullptr)
+    {
+        kwarnln("Already exists");
+        return -EEXIST;
     }
     return node->mkdir_func(node, name);
 }
 
+int VFS::mkdir(const char* pathname)
+{
+    char* bstr = strdup(pathname);
+    char* dstr = strdup(pathname);
+
+    char* base = basename(bstr);
+    char* dir = dirname(dstr);
+
+    kdbgln("mkdir(): creating %s in directory %s", base, dir);
+
+    int result = mkdir(dir, base);
+
+    kfree(bstr);
+    kfree(dstr);
+
+    return result;
+}
+
+bool VFS::exists(const char* pathname)
+{
+    return resolve_path(pathname) != nullptr;
+}
+
 void VFS::mount(Node* mountpoint, Node* mounted)
 {
     if (!mountpoint || !mounted) return;

kernel/src/fs/devices/DeviceFS.cpp

@@ -1,5 +1,6 @@
 #include "fs/devices/DeviceFS.h"
 #include "fs/devices/Console.h"
+#include "fs/devices/Random.h"
 #include "fs/devices/Serial.h"
 #include "fs/devices/Version.h"
 #include "std/stdlib.h"
@@ -25,6 +26,7 @@ VFS::Node* DeviceFS::get()
     devfs_files[devfs_file_count++] = VersionDevice::create_new("version");
     devfs_files[devfs_file_count++] = ConsoleDevice::create_new("console");
     devfs_files[devfs_file_count++] = SerialDevice::create_new("serial");
+    devfs_files[devfs_file_count++] = RandomDevice::create_new("random");
     return devfs_root;
 }
 

kernel/src/fs/devices/Random.cpp

@@ -0,0 +1,38 @@
+#include "fs/devices/Random.h"
+#include "config.h"
+#include "rand/Mersenne.h"
+#include "render/TextRenderer.h"
+#include "std/stdio.h"
+#include "std/stdlib.h"
+#include "std/string.h"
+
+VFS::Node* RandomDevice::create_new(const char* devname)
+{
+    VFS::Node* dev = new VFS::Node;
+    dev->read_func = RandomDevice::read;
+    dev->inode = 0;
+    dev->length = 0;
+    dev->type = VFS_DEVICE;
+    dev->flags = 0;
+    strncpy(dev->name, devname, sizeof(dev->name));
+    return dev;
+}
+
+ssize_t RandomDevice::read(VFS::Node* node, size_t, size_t size, char* buffer)
+{
+    if (!node) return -1;
+    size_t nread = size;
+    while (size >= sizeof(uint64_t))
+    {
+        *(uint64_t*)buffer = Mersenne::get();
+        size -= sizeof(uint64_t);
+        buffer += sizeof(uint64_t);
+    }
+    while (size)
+    {
+        *buffer = (char)(Mersenne::get() & 0xFF);
+        size--;
+        buffer++;
+    }
+    return (ssize_t)nread;
+}

kernel/src/gdt/GDT.cpp

@@ -1,7 +1,7 @@
 #define MODULE "gdt"
 
 #include "gdt/GDT.h"
-#include "assert.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "memory/MemoryManager.h"
 #include "std/string.h"

kernel/src/init/Init.cpp

@@ -1,12 +1,12 @@
 #define MODULE "init"
 
 #include "init/Init.h"
-#include "assert.h"
 #include "bootboot.h"
 #include "cpu/CPU.h"
 #include "init/InitRD.h"
 #include "interrupts/Interrupts.h"
 #include "io/Serial.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "memory/MemoryManager.h"
 #include "memory/PMM.h"

kernel/src/init/InitRD.cpp

@@ -2,6 +2,7 @@
 
 #include "init/InitRD.h"
 #include "bootboot.h"
+#include "errno.h"
 #include "fs/VFS.h"
 #include "io/Serial.h"
 #include "log/Log.h"
@@ -190,23 +191,23 @@ int initrd_mkdir(VFS::Node* node, const char* name) // FIXME: Return proper erro
     if (total_dirs >= 32)
     {
         kwarnln("mkdir() failed: too many directories");
-        return -1;
+        return -ENOSPC;
     }
     if (node->inode > total_dirs)
     {
         kwarnln("mkdir() failed: invalid node");
-        return -1;
+        return -EINVAL;
     }
     if (!(node->type & VFS_DIRECTORY))
     {
         kwarnln("mkdir() failed: not a directory");
-        return -1;
+        return -ENOTDIR;
     }
     InitRD::Directory& parent = dirs[node->inode];
     if (parent.entries == INITRD_MAX_FILES_IN_DIR)
     {
-        kwarnln("mkdir() failed: parent is null");
+        kwarnln("mkdir() failed: parent is full");
-        return -1;
+        return -ENOSPC;
     }
     uint64_t inode = total_dirs;
     VFS::Node& new_node = nodes[total_nodes++];

kernel/src/interrupts/Entry.cpp

@@ -1,10 +1,10 @@
 #define MODULE "isr"
 
-#include "assert.h"
 #include "interrupts/Context.h"
 #include "interrupts/IRQ.h"
 #include "interrupts/Interrupts.h"
 #include "io/Serial.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "misc/hang.h"
 #include "panic/Panic.h"

kernel/src/interrupts/IDT.cpp

@@ -1,7 +1,7 @@
 #define MODULE "idt"
 
 #include "interrupts/IDT.h"
-#include "assert.h"
+#include "kassert.h"
 #include "log/Log.h"
 
 struct IDTEntry

kernel/src/log/Log.cpp

@@ -80,4 +80,9 @@ void KernelLog::toggle_log_level(LogLevel level)
 void KernelLog::toggle_log_backend(Backend backend)
 {
     backend_mask ^= (1 << (int)backend);
+}
+
+void KernelLog::enable_log_backend(Backend backend)
+{
+    backend_mask |= (1 << (int)backend);
 }

kernel/src/main.cpp

@@ -1,40 +1,26 @@
 #define MODULE "main"
 
-#include "acpi/RSDT.h"
-#include "assert.h"
 #include "config.h"
 #include "cpu/CPU.h"
-#include "fs/VFS.h"
 #include "fs/devices/DeviceFS.h"
 #include "gdt/GDT.h"
 #include "init/Init.h"
-#include "init/InitRD.h"
 #include "interrupts/IDT.h"
 #include "interrupts/Install.h"
 #include "interrupts/Interrupts.h"
-#include "io/PCI.h"
 #include "io/PIC.h"
-#include "io/Serial.h"
+#include "kassert.h"
 #include "log/Log.h"
-#include "memory/AddressSpace.h"
 #include "memory/Memory.h"
-#include "memory/MemoryManager.h"
 #include "memory/MemoryMap.h"
-#include "memory/PMM.h"
+#include "misc/hang.h"
-#include "memory/VMM.h"
-#include "misc/PCITypes.h"
-#include "misc/reboot.h"
-#include "panic/Panic.h"
-#include "rand/Mersenne.h"
-#include "render/Framebuffer.h"
-#include "render/TextRenderer.h"
-#include "std/stdio.h"
 #include "std/stdlib.h"
-#include "std/string.h"
-#include "sys/elf/ELFLoader.h"
 #include "thread/PIT.h"
 #include "thread/Scheduler.h"
 
+#define STRINGIZE(x) #x
+#define STRINGIZE_VALUE_OF(x) STRINGIZE(x)
+
 extern "C" void _start()
 {
     Init::check_magic();
@@ -65,7 +51,13 @@ extern "C" void _start()
 
     kinfoln("Prepared scheduler");
 
-    Scheduler::add_kernel_task([]() {
+#ifdef RUN_TEST_AS_INIT
+    ASSERT(Scheduler::load_user_task(STRINGIZE_VALUE_OF(RUN_TEST_AS_INIT)) > 0);
+#else
+    ASSERT(Scheduler::load_user_task("/bin/init") > 0);
+#endif
+
+    Scheduler::add_kernel_task("[moon-reaper]", []() {
         while (1)
         {
             sleep(400);
@@ -73,24 +65,18 @@ extern "C" void _start()
         }
     });
 
-    Scheduler::load_user_task("/bin/init");
-
     kinfoln("Prepared scheduler tasks");
 
-    ASSERT(VFS::mkdir("/", "dev") == 0);
+    ASSERT(VFS::mkdir("/dev") == 0);
     VFS::mount("/dev", DeviceFS::get());
 
     Init::finish_kernel_boot();
 
     PIC::remap();
-    PIC::enable_master(0b11111100); // enable keyboard and PIT
+    PIC::enable_master(0b11111100);
     PIC::enable_slave(0b11111111);
 
-    kinfoln("Interrupts enabled");
+    Interrupts::enable();
 
-    PCI::scan([](PCI::Device& dev) {
+    while (1) halt();
-        kinfoln("Found PCI device %x:%x, %s", dev.id().vendor, dev.id().device, pci_type_name(dev.type()));
-    });
-
-    Scheduler::exit(0);
 }

kernel/src/memory/AddressSpace.cpp

@@ -4,24 +4,20 @@
 #include "log/Log.h"
 #include "memory/PMM.h"
 #include "memory/VMM.h"
+#include "std/stdlib.h"
+#include "std/string.h"
 #include "utils/move.h"
 
 AddressSpace AddressSpace::create()
 {
     AddressSpace result;
     result.m_pml4 = (PageTable*)PMM::request_page();
-    result.m_cloned = false;
     VMM::install_kernel_page_directory_into_address_space(result);
     return move(result);
 }
 
 void AddressSpace::destroy()
 {
-    if (m_cloned)
-    {
-        kdbgln("Will not destroy a cloned address space, I don't own it");
-        return;
-    }
     uint64_t pages_freed = 0;
     for (int i = 0; i < 512; i++)
     {
@@ -78,18 +74,128 @@ void AddressSpace::destroy()
     kdbgln("Reclaimed %ld pages from address space!", pages_freed);
 }
 
-void AddressSpace::detach()
+void AddressSpace::clear()
 {
-    if (!m_cloned) return;
+    uint64_t pages_freed = 0;
-    m_pml4 = (PageTable*)PMM::request_page();
+    for (int i = 0; i < 512; i++)
-    VMM::install_kernel_page_directory_into_address_space(*this);
+    {
-    m_cloned = false;
+        PageDirectoryEntry& pdp_pde = m_pml4->entries[i];
+        if (!pdp_pde.present) continue;
+        if (pdp_pde.larger_pages)
+        {
+            pages_freed++;
+            PMM::free_page((void*)pdp_pde.get_address());
+            continue;
+        }
+        PageTable* pdp = (PageTable*)pdp_pde.get_address();
+        for (int j = 0; j < 511; j++) // skip the last page directory, it's the kernel one
+        {
+            PageDirectoryEntry& pd_pde = pdp->entries[j];
+            if (!pd_pde.present) continue;
+            if (pd_pde.larger_pages)
+            {
+                pages_freed++;
+                PMM::free_page((void*)pd_pde.get_address());
+                continue;
+            }
+            PageTable* pd = (PageTable*)pd_pde.get_address();
+            for (int k = 0; k < 512; k++)
+            {
+                PageDirectoryEntry& pt_pde = pd->entries[k];
+                if (!pt_pde.present) continue;
+                if (pt_pde.larger_pages)
+                {
+                    pages_freed++;
+                    PMM::free_page((void*)pt_pde.get_address());
+                    continue;
+                }
+                PageTable* pt = (PageTable*)pt_pde.get_address();
+                for (int l = 0; l < 512; l++)
+                {
+                    PageDirectoryEntry& pde = pt->entries[l];
+                    if (!pde.present) continue;
+                    pages_freed++;
+                    PMM::free_page((void*)pde.get_address());
+                }
+                pages_freed++;
+                PMM::free_page(pt);
+            }
+            pages_freed++;
+            PMM::free_page(pd);
+        }
+        pages_freed++;
+        PMM::free_page(pdp);
+    }
+
+    kdbgln("Reclaimed %ld pages from address space!", pages_freed);
 }
 
-AddressSpace AddressSpace::clone()
+AddressSpace AddressSpace::clone() // FIXME: Add out-of-memory checks to this function.
 {
     AddressSpace result;
-    result.m_pml4 = m_pml4;
+    result.m_pml4 = (PageTable*)PMM::request_page();
-    result.m_cloned = true;
+    if (!result.m_pml4) return result;
+    memcpy(result.m_pml4, m_pml4, PAGE_SIZE);
+    for (int i = 0; i < 512; i++)
+    {
+        PageDirectoryEntry& pdp_pde = m_pml4->entries[i];
+        PageDirectoryEntry& cloned_pdp_pde = result.m_pml4->entries[i];
+        if (!pdp_pde.present) continue;
+        if (pdp_pde.larger_pages)
+        {
+            void* cloned = PMM::request_page();
+            memcpy(cloned, (void*)pdp_pde.get_address(), PAGE_SIZE);
+            cloned_pdp_pde.set_address((uint64_t)cloned);
+            continue;
+        }
+        PageTable* pdp = (PageTable*)pdp_pde.get_address();
+        PageTable* cloned_pdp = (PageTable*)PMM::request_page();
+        memcpy(cloned_pdp, pdp, PAGE_SIZE);
+        cloned_pdp_pde.set_address((uint64_t)cloned_pdp);
+        for (int j = 0; j < 511; j++) // skip the last page directory, it's the kernel one
+        {
+            PageDirectoryEntry& pd_pde = pdp->entries[j];
+            PageDirectoryEntry& cloned_pd_pde = cloned_pdp->entries[j];
+            if (!pd_pde.present) continue;
+            if (pd_pde.larger_pages)
+            {
+                void* cloned = PMM::request_page();
+                memcpy(cloned, (void*)pd_pde.get_address(), PAGE_SIZE);
+                cloned_pd_pde.set_address((uint64_t)cloned);
+                continue;
+            }
+            PageTable* pd = (PageTable*)pd_pde.get_address();
+            PageTable* cloned_pd = (PageTable*)PMM::request_page();
+            memcpy(cloned_pd, pd, PAGE_SIZE);
+            cloned_pd_pde.set_address((uint64_t)cloned_pd);
+            for (int k = 0; k < 512; k++)
+            {
+                PageDirectoryEntry& pt_pde = pd->entries[k];
+                PageDirectoryEntry& cloned_pt_pde = cloned_pd->entries[k];
+                if (!pt_pde.present) continue;
+                if (pt_pde.larger_pages)
+                {
+                    void* cloned = PMM::request_page();
+                    memcpy(cloned, (void*)pt_pde.get_address(), PAGE_SIZE);
+                    cloned_pt_pde.set_address((uint64_t)cloned);
+                    continue;
+                }
+                PageTable* pt = (PageTable*)pt_pde.get_address();
+                PageTable* cloned_pt = (PageTable*)PMM::request_page();
+                memcpy(cloned_pt, pt, PAGE_SIZE);
+                cloned_pt_pde.set_address((uint64_t)cloned_pt);
+                for (int l = 0; l < 512; l++)
+                {
+                    PageDirectoryEntry& pde = pt->entries[l];
+                    PageDirectoryEntry& cloned_pde = cloned_pt->entries[l];
+                    if (!pde.present) continue;
+                    void* cloned = PMM::request_page();
+                    memcpy(cloned, (void*)pde.get_address(), PAGE_SIZE);
+                    cloned_pde.set_address((uint64_t)cloned);
+                    continue;
+                }
+            }
+        }
+    }
     return result;
 }

kernel/src/memory/MemoryManager.cpp

@@ -3,7 +3,7 @@
 #include "log/Log.h"
 #endif
 
-#include "assert.h"
+#include "kassert.h"
 #include "memory/KernelHeap.h"
 #include "memory/MemoryManager.h"
 #include "memory/PMM.h"

kernel/src/memory/PMM.cpp

@@ -1,8 +1,8 @@
 #define MODULE "mem"
 
 #include "memory/PMM.h"
-#include "assert.h"
 #include "bootboot.h"
+#include "kassert.h"
 #include "memory/Memory.h"
 #include "memory/MemoryManager.h"
 #include "misc/utils.h"

kernel/src/memory/UserHeap.cpp

@@ -0,0 +1,164 @@
+#define MODULE "mem"
+
+#include "memory/UserHeap.h"
+#include "log/Log.h"
+#include "misc/utils.h"
+#include "std/stdlib.h"
+#include "std/string.h"
+
+#ifndef USER_HEAP_DEBUG
+#undef kdbgln
+#define kdbgln(...)
+#endif
+
+#ifndef PAGE_SIZE
+#define PAGE_SIZE 4096
+#endif
+
+#define ALLOC_BASE 0xa00000
+
+#define INITIAL_SIZE 0x2000
+#define EXPAND_SIZE 0x1000
+
+bool UserHeap::init()
+{
+    bitmap = (uint8_t*)kmalloc(INITIAL_SIZE);
+    if (!bitmap) return false;
+    bitmap_size = INITIAL_SIZE;
+    memset(bitmap, 0, bitmap_size);
+    kdbgln("new user heap, bitmap at %p, size %ld", (void*)bitmap, bitmap_size);
+    return true;
+}
+
+bool UserHeap::inherit(UserHeap& other)
+{
+    bitmap = (uint8_t*)kmalloc(other.bitmap_size);
+    if (!bitmap) return false;
+    bitmap_size = other.bitmap_size;
+    memcpy(bitmap, other.bitmap, bitmap_size);
+    kdbgln("child user heap, bitmap at %p, size %ld", (void*)bitmap, bitmap_size);
+    return true;
+}
+
+void UserHeap::free()
+{
+    kdbgln("freeing user heap, bitmap at %p, size %ld", (void*)bitmap, bitmap_size);
+    kfree(bitmap);
+}
+
+bool UserHeap::try_expand()
+{
+    kdbgln("attempting to expand user heap");
+    void* new_bitmap = krealloc(bitmap, bitmap_size + EXPAND_SIZE);
+    if (!new_bitmap)
+    {
+        kdbgln("expansion failed");
+        return false;
+    }
+    bitmap = (uint8_t*)new_bitmap;
+    memset(bitmap + bitmap_size, 0, EXPAND_SIZE);
+    bitmap_size += EXPAND_SIZE;
+    kdbgln("expanded user heap, bitmap at %p, size %ld", (void*)bitmap, bitmap_size);
+    return true;
+}
+
+bool UserHeap::try_expand_size(uint64_t size)
+{
+    void* new_bitmap = krealloc(bitmap, bitmap_size + size);
+    if (!new_bitmap)
+    {
+        kdbgln("expansion failed");
+        return false;
+    }
+    bitmap = (uint8_t*)new_bitmap;
+    memset(bitmap + bitmap_size, 0, size);
+    bitmap_size += size;
+    kdbgln("expanded user heap, bitmap at %p, size %ld", (void*)bitmap, bitmap_size);
+    return true;
+}
+
+bool UserHeap::bitmap_read(uint64_t index)
+{
+    return (bitmap[index / 8] & (0b10000000 >> (index % 8))) > 0;
+}
+
+void UserHeap::bitmap_set(uint64_t index, bool value)
+{
+    uint64_t byteIndex = index / 8;
+    uint8_t bitIndexer = 0b10000000 >> (index % 8);
+    bitmap[byteIndex] &= ~bitIndexer;
+    if (value) { bitmap[byteIndex] |= bitIndexer; }
+}
+
+uint64_t UserHeap::request_virtual_page()
+{
+    uint64_t attempts = 0;
+allocate:
+    for (uint64_t index = start_index; index < bitmap_size * 8; index++)
+    {
+        if (bitmap_read(index)) continue;
+        bitmap_set(index, true);
+        start_index = index + 1;
+        return ALLOC_BASE + (index * PAGE_SIZE);
+    }
+
+    if (attempts == 0 && try_expand()) // We are allocating ONE PAGE, only one attempt should be necessary.
+    {
+        attempts++;
+        goto allocate;
+    }
+
+    return 0;
+}
+
+uint64_t UserHeap::request_virtual_pages(uint64_t count)
+{
+    uint64_t attempts = 0;
+allocate:
+    uint64_t contiguous = 0;
+    uint64_t contiguous_start = 0;
+    for (uint64_t index = start_index; index < bitmap_size * 8; index++)
+    {
+        if (bitmap_read(index))
+        {
+            contiguous = 0;
+            continue;
+        }
+        if (contiguous == 0)
+        {
+            contiguous_start = index;
+            contiguous++;
+        }
+        else
+            contiguous++;
+        if (contiguous == count)
+        {
+            for (uint64_t i = 0; i < count; i++) bitmap_set(contiguous_start + i, true);
+            return ALLOC_BASE + (contiguous_start * PAGE_SIZE);
+        }
+    }
+
+    if (attempts == 0 && try_expand_size(Utilities::get_blocks_from_size(8, count) + 256))
+    {
+        attempts++;
+        goto allocate;
+    }
+
+    return 0;
+}
+
+void UserHeap::free_virtual_page(uint64_t address)
+{
+    if (address < ALLOC_BASE || address >= (ALLOC_BASE + bitmap_size * 8 * PAGE_SIZE)) return;
+    uint64_t index = (address - ALLOC_BASE) / PAGE_SIZE;
+    bitmap_set(index, false);
+    if (start_index > index) start_index = index;
+}
+
+void UserHeap::free_virtual_pages(uint64_t address, uint64_t count)
+{
+    if (address < ALLOC_BASE || address >= (ALLOC_BASE + bitmap_size * 8 * PAGE_SIZE)) return;
+    uint64_t index = (address - ALLOC_BASE) / PAGE_SIZE;
+    for (uint64_t i = 0; i < count; i++) { bitmap_set(index + i, false); }
+    if (start_index > index) start_index = index;
+}

kernel/src/memory/VMM.cpp

@@ -1,7 +1,7 @@
 #define MODULE "vmm"
 
 #include "memory/VMM.h"
-#include "assert.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "memory/PMM.h"
 #include "misc/utils.h"
@@ -275,13 +275,19 @@ void VMM::install_kernel_page_directory_into_address_space(AddressSpace& space)
     PageTable* kernel_last_pdp = (PageTable*)kernel_pml4->entries[511].get_address();
     PageTable* kernel_last_pd = (PageTable*)kernel_last_pdp->entries[511].get_address();
 
-    PageTable* space_last_pdp = (PageTable*)PMM::request_page();
-
     PageDirectoryEntry& space_last_pdp_pde = space_pml4->entries[511];
 
-    space_last_pdp_pde.present = true;
+    PageTable* space_last_pdp;
-    space_last_pdp_pde.read_write = true;
+
-    space_last_pdp_pde.set_address((uint64_t)space_last_pdp);
+    if (!space_last_pdp_pde.present)
+    {
+        space_last_pdp = (PageTable*)PMM::request_page();
+
+        space_last_pdp_pde.present = true;
+        space_last_pdp_pde.read_write = true;
+        space_last_pdp_pde.set_address((uint64_t)space_last_pdp);
+    }
+    else { space_last_pdp = (PageTable*)space_last_pdp_pde.get_address(); }
 
     PageDirectoryEntry& space_last_pd_pde = space_last_pdp->entries[511];
 

kernel/src/misc/config.cpp

@@ -8,7 +8,7 @@
 #endif
 
 #ifndef MOON_MINOR
-#define MOON_MINOR 11
+#define MOON_MINOR 12
 #endif
 
 #ifndef _MOON_SUFFIX

kernel/src/misc/stack.cpp

@@ -1,9 +1,14 @@
 #define MODULE "stack"
 
-#include "panic/Panic.h"
+#include "log/Log.h"
+#include "misc/hang.h"
+#include "render/TextRenderer.h"
 #include <stdint.h>
 
 extern "C" void __stack_chk_fail()
 {
-    panic("Stack smashing detected");
+    KernelLog::enable_log_backend(Backend::Console);
+    TextRenderer::reset();
+    kerrorln("stack smashing detected");
+    hang();
 }

kernel/src/panic/Panic.asm

@@ -1,34 +0,0 @@
-extern __do_panic
-global __panic
-
-__panic:
-    push BYTE 0 ; interrupt number
-    push BYTE 0 ; error code
-    push rax
-    push rbx
-    push rcx
-    push rdx
-    push rbp
-    push rdi
-    push rsi
-    push r8
-    push r9
-    push r10
-    push r11
-    push r12
-    push r13
-    push r14
-    push r15
-
-    mov r8, cr2
-    push r8
-
-    mov rsi, rdi
-    mov rdi, rsp
-
-    call __do_panic
-
-    cli
-loop:    
-    hlt
-    jmp loop

kernel/src/panic/Panic.cpp

@@ -6,33 +6,45 @@
 #include "io/PIC.h"
 #include "log/Log.h"
 #include "misc/MSR.h"
+#include "render/TextRenderer.h"
 #include "std/stdio.h"
 #include "thread/Scheduler.h"
 #include "trace/StackTracer.h"
 
-static void dump_registers(Context* context)
+void dump_registers(Context* context)
 {
-    printf("-- Registers: \n");
+    kinfoln("-- Registers:");
-    printf("rax: %lx, rbx: %lx, rcx: %lx, rdx: %lx\n", context->rax, context->rbx, context->rcx, context->rdx);
+    kinfoln("rax: %lx, rbx: %lx, rcx: %lx, rdx: %lx", context->rax, context->rbx, context->rcx, context->rdx);
-    printf("rsi: %lx, rdi: %lx, rsp: %lx, rbp: %lx\n", context->rsi, context->rdi, context->rsp, context->rbp);
+    kinfoln("rsi: %lx, rdi: %lx, rsp: %lx, rbp: %lx", context->rsi, context->rdi, context->rsp, context->rbp);
-    printf("r8: %lx, r9: %lx, r10: %lx, r11: %lx\n", context->r8, context->r9, context->r10, context->r11);
+    kinfoln("r8: %lx, r9: %lx, r10: %lx, r11: %lx", context->r8, context->r9, context->r10, context->r11);
-    printf("r12: %lx, r13: %lx, r14: %lx, r15: %lx\n", context->r12, context->r13, context->r14, context->r15);
+    kinfoln("r12: %lx, r13: %lx, r14: %lx, r15: %lx", context->r12, context->r13, context->r14, context->r15);
-    printf("rip: %lx, cs: %lx, ss: %lx\n", context->rip, context->cs, context->ss);
+    kinfoln("rip: %lx, cs: %lx, ss: %lx", context->rip, context->cs, context->ss);
-    printf("rflags: %lx, cr2: %lx\n", context->rflags, context->cr2);
+    kinfoln("rflags: %lx, cr2: %lx", context->rflags, context->cr2);
-    printf("ia32_efer: %lx\n", MSR::read_from(IA32_EFER_MSR));
+    kinfoln("ia32_efer: %lx", MSR::read_from(IA32_EFER_MSR));
 }
 
-[[noreturn]] static void __panic_stub(Context* context)
+[[noreturn]] void __panic_stub(Context* context)
 {
-    dump_registers(context);
+    if (context) dump_registers(context);
 
     if (InitRD::is_initialized())
     {
-        printf("-- Stack trace:\n");
+        kinfoln("-- Stack trace:");
-        StackTracer tracer(context->rbp);
+        if (context)
-        tracer.trace_with_ip(context->rip);
+        {
+            StackTracer tracer(context->rbp);
+            tracer.trace_with_ip(context->rip);
+        }
+        else
+        {
+            uintptr_t rbp;
+
+            asm volatile("mov %%rbp, %0" : "=r"(rbp));
+            StackTracer tracer(rbp);
+            tracer.trace();
+        }
     }
-    else { printf("-- No stack trace available\n"); }
+    else { kinfoln("-- No stack trace available"); }
 
     PIC::enable_master(0b11111101); // enable keyboard only
     PIC::enable_slave(0b11111111);
@@ -53,10 +65,14 @@ static void dump_registers(Context* context)
     while (1) asm volatile("hlt");
 }
 
-extern "C" [[noreturn]] void __do_int_panic(Context* context, const char* file, int line, const char* message)
+extern "C" [[noreturn]] bool __do_int_panic(Context* context, const char* file, int line, const char* message)
 {
     asm volatile("cli");
 
+    KernelLog::enable_log_backend(Backend::Console);
+
+    TextRenderer::reset();
+
     if (context->number >= 0x20 && context->number < 0x30) { PIC::send_eoi((uint8_t)(context->irq_number & 0xFF)); }
 
     Task* task;
@@ -69,11 +85,20 @@ extern "C" [[noreturn]] void __do_int_panic(Context* context, const char* file,
     __panic_stub(context);
 }
 
-extern "C" [[noreturn]] void __do_panic(Context* context, const char* message)
+extern "C" [[noreturn]] bool __do_panic(const char* file, int line, const char* message)
 {
-    Task* task;
+    asm volatile("cli");
-    if ((task = Scheduler::current_task())) { kerrorln("Kernel panic in task %ld: %s", task->id, message); }
-    else { kerrorln("Kernel panic: %s", message); }
 
-    __panic_stub(context);
+    KernelLog::enable_log_backend(Backend::Console);
+
+    TextRenderer::reset();
+
+    Task* task;
+    if ((task = Scheduler::current_task()))
+    {
+        kerrorln("Kernel panic in task %ld, at %s, line %d: %s", task->id, file, line, message);
+    }
+    else { kerrorln("Kernel panic at %s, line %d: %s", file, line, message); }
+
+    __panic_stub(nullptr);
 }

kernel/src/rand/Mersenne.cpp

@@ -1,7 +1,7 @@
 #define MODULE "rand"
 
 #include "rand/Mersenne.h"
-#include "assert.h"
+#include "kassert.h"
 #include <stddef.h>
 
 typedef uint64_t word_t;

kernel/src/std/libgen.cpp

@@ -0,0 +1,47 @@
+#include "std/libgen.h"
+#include "std/string.h"
+
+static char dot[] = ".";
+
+char* basename(char* path)
+{
+    // If path is NULL, or the string's length is 0, return .
+    if (!path) return dot;
+    size_t len = strlen(path);
+    if (!len) return dot;
+
+    // Strip trailing slashes.
+    char* it = path + len - 1;
+    while (*it == '/' && it != path) { it--; }
+    *(it + 1) = 0;
+    if (it == path) return path;
+
+    // Return path from the first character if there are no more slashes, or from the first character after the last
+    // slash.
+    char* beg = strrchr(path, '/');
+    if (!beg) return path;
+    return beg + 1;
+}
+
+char* dirname(char* path)
+{
+    // If path is NULL, or the string's length is 0, return .
+    if (!path) return dot;
+    size_t len = strlen(path);
+    if (!len) return dot;
+
+    // Strip trailing slashes.
+    char* it = path + len - 1;
+    while (*it == '/' && it != path) { it--; }
+    *(char*)(it + 1) = 0;
+    if (it == path) return path;
+
+    // Search for the last slash. If there is none, return .
+    // Otherwise, we end the string there and return.
+    char* end = strrchr(path, '/');
+    if (!end) return dot;
+    if (end != path) *end = 0;
+    else
+        *(end + 1) = 0;
+    return path;
+}

kernel/src/std/string.cpp

@@ -17,11 +17,29 @@ char* strcpy(char* dest, const char* src)
 
 char* strncpy(char* dest, const char* src, size_t n)
 {
-    size_t src_len = strlen(src) + 1; // NULL byte
+    size_t i;
-    memcpy(dest, src, src_len > n ? n : src_len);
+    for (i = 0; i < n && src[i] != 0; i++) dest[i] = src[i];
+    for (; i < n; i++) dest[i] = 0;
     return dest;
 }
 
+size_t strlcpy(char* dest, const char* src, size_t size)
+{
+    size_t len = strlen(src);
+    if (size == 0) return len;
+    if (len < (size - 1))
+    {
+        memcpy(dest, src, len);
+        dest[len] = 0;
+    }
+    else
+    {
+        memcpy(dest, src, size - 1);
+        dest[size - 1] = 0;
+    }
+    return len;
+}
+
 int strcmp(const char* a, const char* b)
 {
     while (*a && (*a == *b))
@@ -130,4 +148,12 @@ char* strdup(const char* src)
     char* duplicated = (char*)kmalloc(length + 1);
     memcpy(duplicated, src, length + 1);
     return duplicated;
+}
+
+char* strrchr(const char* str, int c)
+{
+    const char* s = str + strlen(str);
+    while (s != str && *s != (char)c) s--;
+    if (*s == (char)c) return const_cast<char*>(s);
+    return NULL;
 }

kernel/src/sys/Syscall.cpp

@@ -16,8 +16,7 @@ void Syscall::entry(Context* context)
     case SYS_sleep: sys_sleep(context, context->rdi); break;
     case SYS_write: sys_write(context, (int)context->rdi, context->rsi, (const char*)context->rdx); break;
     case SYS_paint: sys_paint(context, context->rdi, context->rsi, context->rdx, context->r10, context->r8); break;
-    case SYS_rand: sys_rand(context); break;
+    case SYS_getpid: sys_getpid(context); break;
-    case SYS_gettid: sys_gettid(context); break;
     case SYS_mmap: sys_mmap(context, (void*)context->rdi, context->rsi, (int)context->rdx); break;
     case SYS_munmap: sys_munmap(context, (void*)context->rdi, context->rsi); break;
     case SYS_open: sys_open(context, (const char*)context->rdi, (int)context->rsi); break;
@@ -25,12 +24,17 @@ void Syscall::entry(Context* context)
     case SYS_close: sys_close(context, (int)context->rdi); break;
     case SYS_seek: sys_seek(context, (int)context->rdi, (long)context->rsi, (int)context->rdx); break;
     case SYS_exec: sys_exec(context, (const char*)context->rdi); break;
+    case SYS_fcntl: sys_fcntl(context, (int)context->rdi, (int)context->rsi, context->rdx); break;
+    case SYS_mprotect: sys_mprotect(context, (void*)context->rdi, context->rsi, (int)context->rdx); break;
+    case SYS_clock: sys_clock(context); break;
+    case SYS_mkdir: sys_mkdir(context, (const char*)context->rdi); break;
+    case SYS_fork: sys_fork(context); break;
     default: context->rax = -ENOSYS; break;
     }
     VMM::exit_syscall_context();
 }
 
-char* Syscall::strdup_from_user(const char* user_string)
+char* Syscall::strdup_from_user(const char* user_string) // FIXME: This function is a little hacky.
 {
     uint64_t phys = VMM::get_physical((uint64_t)user_string);
     if (phys == (uint64_t)-1) { return nullptr; }

kernel/src/sys/clock.cpp

@@ -0,0 +1,9 @@
+#include "interrupts/Context.h"
+#include "thread/Scheduler.h"
+
+void sys_clock(Context* context)
+{
+    Task* current_task = Scheduler::current_task();
+    context->rax = (long)current_task->cpu_time;
+    return;
+}

kernel/src/sys/elf/ELFLoader.cpp

@@ -1,10 +1,10 @@
 #define MODULE "elf"
 
 #include "sys/elf/ELFLoader.h"
-#include "assert.h"
 #include "errno.h"
 #include "fs/VFS.h"
 #include "init/InitRD.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "memory/Memory.h"
 #include "memory/MemoryManager.h"
@@ -123,40 +123,40 @@ ELFImage* ELFLoader::load_elf_from_vfs(VFS::Node* node)
 long ELFLoader::check_elf_image(VFS::Node* node)
 {
     Elf64_Ehdr elf_ehdr;
-    if (VFS::read(node, 0, sizeof(elf_ehdr), (char*)&elf_ehdr) < 0)
+    if (VFS::read(node, 0, sizeof(elf_ehdr), (char*)&elf_ehdr) < (long)sizeof(elf_ehdr))
     {
         kwarnln("Unable to read ELF header");
-        return -1;
+        return -ENOEXEC;
     }
     if (strncmp((const char*)elf_ehdr.e_ident, ELFMAG, SELFMAG) != 0)
     {
         kwarnln("ELF file has invalid magic, skipping");
-        return -1;
+        return -ENOEXEC;
     }
     if (elf_ehdr.e_ident[EI_CLASS] != ELFCLASS64)
     {
         kwarnln("ELF file is not ELF64, skipping");
-        return -1;
+        return -ENOEXEC;
     }
     if (elf_ehdr.e_ident[EI_DATA] != ELFDATA2LSB)
     {
         kwarnln("ELF file is not little-endian, skipping");
-        return -1;
+        return -ENOEXEC;
     }
     if (elf_ehdr.e_type != ET_EXEC)
     {
         kwarnln("not supported: ELF file is not an executable");
-        return -1;
+        return -ENOEXEC;
     }
     if (elf_ehdr.e_machine != EM_MACH)
     {
         kwarnln("Unsupported target machine");
-        return -1;
+        return -ENOEXEC;
     }
     if (elf_ehdr.e_phnum == 0)
     {
         kwarnln("ELF file has no PHDRS");
-        return -1;
+        return -ENOEXEC;
     }
     int i;
     int loadable_sections = 0;
@@ -170,12 +170,12 @@ long ELFLoader::check_elf_image(VFS::Node* node)
             if (!phdr.p_vaddr)
             {
                 kerrorln("segment address is NULL, this is invalid :(");
-                return -1;
+                return -ENOEXEC;
             }
             if (Memory::is_kernel_address(phdr.p_vaddr) || Memory::is_kernel_address(phdr.p_vaddr + phdr.p_memsz))
             {
                 kerrorln("trying to load ELF into kernel memory");
-                return -1;
+                return -ENOEXEC;
             }
             loadable_sections++;
             memusage += Utilities::get_blocks_from_size(PAGE_SIZE, phdr.p_memsz) * PAGE_SIZE;
@@ -184,7 +184,7 @@ long ELFLoader::check_elf_image(VFS::Node* node)
     if (!loadable_sections)
     {
         kwarnln("No loadable sections");
-        return -1;
+        return -ENOEXEC;
     }
     return memusage;
 }

kernel/src/sys/exec.cpp

@@ -1,8 +1,9 @@
 #define MODULE "exec"
 
-#include "assert.h"
 #include "errno.h"
 #include "interrupts/Interrupts.h"
+#include "kassert.h"
+#include "log/Log.h"
 #include "memory/MemoryManager.h"
 #include "memory/PMM.h"
 #include "memory/VMM.h"
@@ -12,11 +13,48 @@
 #include "sys/elf/ELFLoader.h"
 #include "thread/Scheduler.h"
 
+void sys_fork(Context* context)
+{
+    kinfoln("fork(): attempting fork");
+
+    Task* parent = Scheduler::current_task();
+
+    Task* child = Scheduler::create_user_task();
+    if (!child)
+    {
+        context->rax = -ENOMEM;
+        return;
+    }
+
+    if (!child->allocator.inherit(parent->allocator))
+    {
+        child->state = child->Exited;
+        child->exit_status = -127; // so the reaper reaps it on next reaping
+        context->rax = -ENOMEM;
+        return;
+    }
+
+    child->save_context(context);
+    child->save_floating();
+
+    for (int i = 0; i < TASK_MAX_FDS; i++) { child->files[i] = parent->files[i]; }
+
+    child->address_space = parent->address_space.clone();
+
+    child->regs.rax = 0;
+    context->rax = child->id;
+
+    strlcpy(child->name, parent->name, sizeof(child->name));
+
+    child->state = child->Running;
+
+    kinfoln("fork(): forked parent %ld into child %ld", parent->id, child->id);
+
+    return;
+}
+
 void sys_exec(Context* context, const char* pathname)
 {
-    /*context->rax = -ENOSYS; // FIXME: Make exec() work under separate address spaces.
-    return;*/
-
     char* kpathname = Syscall::strdup_from_user(pathname);
     if (!kpathname)
     {
@@ -49,20 +87,9 @@ void sys_exec(Context* context, const char* pathname)
         return;
     }
 
-    uint64_t allocated_stack = (uint64_t)MemoryManager::get_pages(TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER);
-    if (!allocated_stack)
-    {
-        kfree(kpathname);
-        context->rax = -ENOMEM;
-        return;
-    }
-
-    uint64_t allocated_stack_phys = VMM::get_physical(allocated_stack);
-
     if ((uint64_t)memusage > PMM::get_free())
     {
         kfree(kpathname);
-        MemoryManager::release_pages((void*)allocated_stack, TASK_PAGES_IN_STACK);
         context->rax = -ENOMEM;
         return;
     }
@@ -75,20 +102,25 @@ void sys_exec(Context* context, const char* pathname)
 
     // At this point, pretty much nothing can fail.
 
+    task->allocator.free();
+    task->allocator
+        .init(); // If we had enough space for the old bitmap, we should have enough space for the new bitmap.
+
+    task->address_space.clear();
+    task->allocated_stack = (uint64_t)MemoryManager::get_pages_at(
+        0x100000, TASK_PAGES_IN_STACK,
+        MAP_USER | MAP_READ_WRITE); // If we had enough space for the old stack, there should be enough space for the
+                                    // new stack.
+
     ELFImage* image = ELFLoader::load_elf_from_vfs(program);
     ASSERT(image); // If check_elf_image succeeded, load_elf_from_vfs MUST succeed, unless something has gone terribly
                    // wrong.
 
-    task->allocated_stack = allocated_stack;
+    strlcpy(task->name, kpathname, sizeof(task->name));
-
-    for (uint64_t i = 0; i < TASK_PAGES_IN_STACK; i++)
-    {
-        VMM::map(allocated_stack + (i * PAGE_SIZE), allocated_stack_phys + (i * PAGE_SIZE), MAP_READ_WRITE | MAP_USER);
-    }
 
     Scheduler::reset_task(task, image);
 
-    set_context_from_task(*task, context);
+    task->restore_context(context);
 
     kfree(kpathname);
 

kernel/src/sys/mem.cpp

@@ -3,14 +3,37 @@
 #include "errno.h"
 #include "interrupts/Context.h"
 #include "log/Log.h"
+#include "memory/Memory.h"
 #include "memory/MemoryManager.h"
 #include "memory/VMM.h"
 #include "misc/utils.h"
+#include "thread/Scheduler.h"
 #include <stddef.h>
 
+#define MAP_READ 1
+#define MAP_WRITE 2
+#define MAP_NONE 0
+
 #define MAP_FAIL(errno) 0xffffffffffffff00 | (unsigned char)(errno)
 
-void sys_mmap(Context* context, void* address, size_t size, int flags)
+static const char* format_prot(int prot)
+{
+    static char prot_string[3];
+    prot_string[2] = 0;
+    prot_string[0] = ((prot & MAP_READ) > 0) ? 'r' : '-';
+    prot_string[1] = ((prot & MAP_WRITE) > 0) ? 'w' : '-';
+    return prot_string;
+}
+
+static int mman_flags_from_prot(int prot)
+{
+    prot &= 0b11;
+    if (prot == MAP_NONE) return 0;
+    if ((prot & MAP_WRITE) > 0) return MAP_USER | MAP_READ_WRITE;
+    return MAP_USER;
+}
+
+void sys_mmap(Context* context, void* address, size_t size, int prot)
 {
     if (size < PAGE_SIZE)
     {
@@ -24,12 +47,16 @@ void sys_mmap(Context* context, void* address, size_t size, int flags)
         context->rax = MAP_FAIL(EINVAL);
         return;
     }
-    int real_flags = MAP_USER;
+    int real_flags = mman_flags_from_prot(prot);
-    if (flags & MAP_READ_WRITE) real_flags |= MAP_READ_WRITE;
     if (address)
     {
-        kdbgln("mmap(): %ld pages at address %p, %s", size / PAGE_SIZE, address,
+        kdbgln("mmap(): %ld pages at address %p, %s", size / PAGE_SIZE, address, format_prot(prot));
-               real_flags & MAP_READ_WRITE ? "rw" : "ro");
+        if (Memory::is_kernel_address((uintptr_t)address))
+        {
+            kwarnln("munmap() failed: attempted to unmap a kernel page");
+            context->rax = MAP_FAIL(ENOMEM);
+            return;
+        }
         if (VMM::get_physical((uint64_t)address) != (uint64_t)-1) // Address is already used.
         {
             kwarnln("attempt to map an already mapped address");
@@ -47,14 +74,21 @@ void sys_mmap(Context* context, void* address, size_t size, int flags)
         }
         else
         {
-            kwarnln("mmap() failed");
+            kwarnln("mmap() failed: failed to allocate physical memory");
             context->rax = MAP_FAIL(ENOMEM);
             return;
         }
     }
-    kdbgln("mmap(): %ld pages at any address, %s", Utilities::get_blocks_from_size(PAGE_SIZE, size),
+    kdbgln("mmap(): %ld pages at any address, %s", Utilities::get_blocks_from_size(PAGE_SIZE, size), format_prot(prot));
-           real_flags & MAP_READ_WRITE ? "rw" : "ro");
+    uint64_t ptr =
-    void* result = MemoryManager::get_pages(Utilities::get_blocks_from_size(PAGE_SIZE, size), real_flags);
+        Scheduler::current_task()->allocator.request_virtual_pages(Utilities::get_blocks_from_size(PAGE_SIZE, size));
+    if (!ptr)
+    {
+        kwarnln("mmap() failed: failed to allocate virtual address");
+        context->rax = MAP_FAIL(ENOMEM);
+        return;
+    }
+    void* result = MemoryManager::get_pages_at(ptr, Utilities::get_blocks_from_size(PAGE_SIZE, size), real_flags);
     if (result)
     {
         kdbgln("mmap() succeeded: %p", result);
@@ -63,7 +97,7 @@ void sys_mmap(Context* context, void* address, size_t size, int flags)
     }
     else
     {
-        kwarnln("mmap() failed");
+        kwarnln("mmap() failed: failed to allocate physical memory");
         context->rax = MAP_FAIL(ENOMEM);
         return;
     }
@@ -90,16 +124,68 @@ void sys_munmap(Context* context, void* address, size_t size)
         context->rax = -EINVAL;
         return;
     }
-    uint64_t flags = VMM::get_flags((uint64_t)address);
+    if (Memory::is_kernel_address((uintptr_t)address))
-    if (!(flags & MAP_USER))
     {
-        kwarnln("munmap() failed: attempted to unmap a non-existent or kernel page");
+        kwarnln("munmap() failed: attempted to unmap a kernel page");
+        context->rax = -EINVAL;
+        return;
+    }
+    uint64_t phys = VMM::get_physical((uint64_t)address);
+    if (phys == (uint64_t)-1)
+    {
+        kwarnln("munmap() failed: attempted to unmap a non-existent page");
         context->rax = -EINVAL;
         return;
     }
     uint64_t offset = (uint64_t)address % PAGE_SIZE;
+    Scheduler::current_task()->allocator.free_virtual_pages(((uint64_t)address - offset),
+                                                            Utilities::get_blocks_from_size(PAGE_SIZE, size));
     MemoryManager::release_pages((void*)((uint64_t)address - offset), Utilities::get_blocks_from_size(PAGE_SIZE, size));
     kdbgln("munmap() succeeded");
     context->rax = 0;
     return;
+}
+
+void sys_mprotect(Context* context, void* address, size_t size, int prot)
+{
+    kdbgln("mprotect(): attempting to protect %p with %s", address, format_prot(prot));
+
+    if (size < PAGE_SIZE)
+    {
+        kwarnln("mprotect() failed: size is too small");
+        context->rax = -EINVAL;
+        return;
+    }
+    if (size % PAGE_SIZE)
+    {
+        kwarnln("mprotect() failed: size is not a multiple of PAGE_SIZE");
+        context->rax = -EINVAL;
+        return;
+    }
+    if (!address)
+    {
+        kwarnln("mprotect() failed: attempted to protect page 0");
+        context->rax = -EINVAL;
+        return;
+    }
+    if (Memory::is_kernel_address((uintptr_t)address))
+    {
+        kwarnln("mprotect() failed: attempted to protect a kernel page");
+        context->rax = -EINVAL;
+        return;
+    }
+    uint64_t phys = VMM::get_physical((uint64_t)address);
+    if (phys == (uint64_t)-1)
+    {
+        kwarnln("mprotect() failed: attempted to protect a non-existent page");
+        context->rax = -EINVAL;
+        return;
+    }
+
+    uint64_t offset = (uint64_t)address % PAGE_SIZE;
+    MemoryManager::protect((void*)((uint64_t)address - offset), Utilities::get_blocks_from_size(PAGE_SIZE, size),
+                           mman_flags_from_prot(prot));
+    kdbgln("mprotect() succeeded");
+    context->rax = 0;
+    return;
 }

kernel/src/sys/rand.cpp

@@ -1,7 +0,0 @@
-#include "interrupts/Context.h"
-#include "rand/Mersenne.h"
-
-void sys_rand(Context* context)
-{
-    context->rax = Mersenne::get();
-}

kernel/src/sys/sched.cpp

@@ -20,7 +20,7 @@ void sys_sleep(Context* context, uint64_t ms)
     Scheduler::task_yield(context);
 }
 
-void sys_gettid(Context* context)
+void sys_getpid(Context* context)
 {
     context->rax = Scheduler::current_task()->id;
 }

kernel/src/sys/stdio.cpp

@@ -18,6 +18,47 @@
 #define SEEK_CUR 1
 #define SEEK_END 2
 
+#define FNCTL_DUPFD 0
+
+void sys_fcntl(Context* context, int fd, int command, uintptr_t arg)
+{
+    if (fd >= TASK_MAX_FDS || fd < 0)
+    {
+        context->rax = -EBADF;
+        return;
+    }
+    Task* current_task = Scheduler::current_task();
+    if (!current_task->files[fd].is_open())
+    {
+        context->rax = -EBADF;
+        return;
+    }
+    Descriptor& file = current_task->files[fd];
+    if (command == FNCTL_DUPFD)
+    {
+        if ((int)arg < 0 || (int)arg >= TASK_MAX_FDS)
+        {
+            context->rax = -EINVAL;
+            return;
+        }
+        int dupfd = current_task->alloc_fd_greater_than_or_equal((int)arg);
+        if (dupfd < 0)
+        {
+            context->rax = -EMFILE;
+            return;
+        }
+        current_task->files[dupfd] = file;
+        context->rax = dupfd;
+        kdbgln("fcntl(F_DUPFD): duplicated fd %d, result is %d", fd, dupfd);
+        return;
+    }
+    else
+    {
+        context->rax = -EINVAL;
+        return;
+    }
+}
+
 void sys_seek(Context* context, int fd, long offset, int whence)
 {
     if (whence < SEEK_SET || whence > SEEK_END)
@@ -36,12 +77,13 @@ void sys_seek(Context* context, int fd, long offset, int whence)
         context->rax = -EBADF;
         return;
     }
+    Descriptor& file = current_task->files[fd];
     long new_offset;
     if (whence == SEEK_SET) new_offset = offset;
     else if (whence == SEEK_CUR)
-        new_offset = offset + current_task->files[fd].offset();
+        new_offset = offset + file.offset();
     else if (whence == SEEK_END)
-        new_offset = current_task->files[fd].length() + offset;
+        new_offset = file.length() + offset;
     else
         __builtin_unreachable();
     if (new_offset < 0)
@@ -49,7 +91,12 @@ void sys_seek(Context* context, int fd, long offset, int whence)
         context->rax = -EINVAL; // FIXME: Is this the right error?
         return;
     }
-    int result = current_task->files[fd].seek(new_offset);
+    if (new_offset == file.offset())
+    {
+        context->rax = new_offset;
+        return;
+    }
+    int result = file.seek(new_offset);
     if (result < 0)
     {
         context->rax = result;
@@ -77,12 +124,13 @@ void sys_write(Context* context, int fd, size_t size, const char* addr)
         context->rax = -EBADF;
         return;
     }
-    if (!current_task->files[fd].can_write())
+    Descriptor& file = current_task->files[fd];
+    if (!file.can_write())
     {
         context->rax = -EBADF;
         return;
     }
-    ssize_t result = current_task->files[fd].write(size, (const char*)VMM::get_physical((uint64_t)addr));
+    ssize_t result = file.write(size, (const char*)VMM::get_physical((uint64_t)addr));
     context->rax = (size_t)result;
     return;
 }
@@ -90,13 +138,8 @@ void sys_write(Context* context, int fd, size_t size, const char* addr)
 void sys_open(Context* context, const char* filename, int flags)
 {
     Task* current_task = Scheduler::current_task();
-    int fd;
+    int fd = current_task->alloc_fd();
-    for (fd = 0; fd < TASK_MAX_FDS; fd++)
+    if (fd < 0)
-    {
-        if (!current_task->files[fd].is_open()) break;
-    }
-
-    if (fd == TASK_MAX_FDS)
     {
         context->rax = -EMFILE;
         return;
@@ -178,4 +221,20 @@ void sys_close(Context* context, int fd)
     current_task->files[fd].close();
     context->rax = 0;
     return;
+}
+
+void sys_mkdir(Context* context, const char* filename)
+{
+    char* kfilename = Syscall::strdup_from_user(filename);
+    if (!kfilename)
+    {
+        context->rax = -EFAULT;
+        return;
+    }
+
+    int rc = VFS::mkdir(kfilename);
+
+    kfree(kfilename);
+
+    context->rax = rc;
 }

kernel/src/thread/Scheduler.cpp

@@ -1,10 +1,12 @@
 #define MODULE "sched"
 
 #include "thread/Scheduler.h"
-#include "assert.h"
+#include "errno.h"
 #include "interrupts/Interrupts.h"
+#include "kassert.h"
 #include "log/Log.h"
 #include "memory/MemoryManager.h"
+#include "memory/PMM.h"
 #include "memory/VMM.h"
 #include "misc/hang.h"
 #include "misc/utils.h"
@@ -31,6 +33,51 @@ extern "C" void idle_task_function();
 
 static uint64_t frequency;
 
+template <typename Callback> void sched_for_each_task(Callback callback)
+{
+    Task* task = base_task;
+    if (!task) return;
+    do {
+        bool will_continue = callback(task);
+        if (!will_continue) break;
+        task = task->next_task;
+    } while (task != base_task);
+}
+
+Task* Scheduler::find_by_pid(uint64_t pid)
+{
+    Task* result = nullptr;
+    sched_for_each_task([&](Task* task) {
+        if (task->id == pid)
+        {
+            result = task;
+            return false;
+        }
+        return true;
+    });
+    return result;
+}
+
+void Scheduler::append_task(Task* task)
+{
+    if (!base_task)
+    {
+        ASSERT(!end_task);
+        base_task = task;
+        end_task = base_task;
+        task->next_task = task;
+        task->prev_task = task;
+    }
+    else
+    {
+        end_task->next_task = task;
+        task->prev_task = end_task;
+        base_task->prev_task = task;
+        task->next_task = base_task;
+        end_task = task;
+    }
+}
+
 void Scheduler::init()
 {
     memset(&idle_task, 0, sizeof(Task));
@@ -44,22 +91,12 @@ void Scheduler::init()
     idle_task.user_task = false;
     idle_task.state = idle_task.Idle;
 
-    base_task = new Task;
+    sched_current_task = &idle_task;
-    end_task = base_task;
-    sched_current_task = base_task;
-    sched_current_task->id = free_tid++;
-    sched_current_task->task_time = 20; // gets 20 ms of cpu time before next switch
-    sched_current_task->next_task = sched_current_task;
-    sched_current_task->prev_task = sched_current_task;
-    sched_current_task->state = sched_current_task->Running;
-    sched_current_task->user_task = false;
-    task_num++;
-    // the other registers will be saved next task switch
 
     frequency = 1000 / PIT::frequency();
 }
 
-void Scheduler::add_kernel_task(void (*task)(void))
+void Scheduler::add_kernel_task(const char* taskname, void (*task)(void))
 {
     Task* new_task = new Task;
     ASSERT(new_task);
@@ -76,53 +113,51 @@ void Scheduler::add_kernel_task(void (*task)(void))
     new_task->task_sleep = 0;
     new_task->task_time = 0;
     new_task->cpu_time = 0;
-    end_task->next_task = new_task;
+    strlcpy(new_task->name, taskname, sizeof(new_task->name));
-    new_task->prev_task = end_task;
+    append_task(new_task);
-    base_task->prev_task = new_task;
-    new_task->next_task = base_task;
-    end_task = new_task;
     new_task->state = new_task->Running;
     task_num++;
-    kinfoln("Adding kernel task: starts at %lx, tid %ld, stack at %lx, total tasks: %ld", new_task->regs.rip,
+    kinfoln("Adding kernel task: %s, starts at %lx, PID %ld, stack at %lx, total tasks: %ld", new_task->name,
-            new_task->id, new_task->regs.rsp, task_num);
+            new_task->regs.rip, new_task->id, new_task->regs.rsp, task_num);
 }
 
 Task* Scheduler::create_user_task()
 {
     Task* new_task = new Task;
-    ASSERT(new_task);
+    if (!new_task) return nullptr;
     memset(&new_task->regs, 0, sizeof(Context));
     new_task->user_task = true;
     new_task->id = free_tid++;
-    new_task->allocated_stack = (uint64_t)MemoryManager::get_pages(
-        TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER); // 16 KB is enough for everyone, right?
-    new_task->regs.rsp = get_top_of_stack(new_task->allocated_stack, TASK_PAGES_IN_STACK);
     new_task->task_sleep = 0;
     new_task->task_time = 0;
     new_task->cpu_time = 0;
-    end_task->next_task = new_task;
+    append_task(new_task);
-    new_task->prev_task = end_task;
-    base_task->prev_task = new_task;
-    new_task->next_task = base_task;
-    end_task = new_task;
     task_num++;
     return new_task;
 }
 
-void Scheduler::load_user_task(const char* filename)
+long Scheduler::load_user_task(const char* filename)
 {
     kinfoln("Loading user task: %s", filename);
     Interrupts::push_and_disable();
-    if (ELFLoader::check_elf_image_from_filesystem(filename) < 0)
+    long result;
+    if ((result = ELFLoader::check_elf_image_from_filesystem(filename)) < 0)
     {
         kerrorln("Failed to load %s from initrd", filename);
         Interrupts::pop();
-        return;
+        return result;
     }
+    if ((uint64_t)result > PMM::get_free()) { return -ENOMEM; }
     Task* new_task = new Task;
     ASSERT(new_task);
     memset(&new_task->regs, 0, sizeof(Context));
     new_task->id = free_tid++;
+    if (!new_task->allocator.init())
+    {
+        delete new_task;
+        Interrupts::pop();
+        return -ENOMEM;
+    }
     new_task->address_space = AddressSpace::create();
     VMM::switch_to_user_address_space(new_task->address_space);
     ELFImage* image = ELFLoader::load_elf_from_filesystem(
@@ -132,8 +167,17 @@ void Scheduler::load_user_task(const char* filename)
     new_task->user_task = true;
     new_task->regs.rip = image->entry;
     new_task->image = image;
-    new_task->allocated_stack = (uint64_t)MemoryManager::get_pages(
+    new_task->allocated_stack = (uint64_t)MemoryManager::get_pages_at(
-        TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER); // 16 KB is enough for everyone, right?
+        0x100000, TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER); // 16 KB is enough for everyone, right?
+    if (!new_task->allocated_stack)
+    {
+        new_task->address_space.destroy();
+        delete new_task;
+        ELFLoader::release_elf_image(image);
+        VMM::switch_back_to_kernel_address_space();
+        Interrupts::pop();
+        return -ENOMEM;
+    }
     new_task->regs.rsp = get_top_of_stack(new_task->allocated_stack, TASK_PAGES_IN_STACK);
     new_task->regs.cs = 0x18 | 0x03;
     new_task->regs.ss = 0x20 | 0x03;
@@ -142,17 +186,15 @@ void Scheduler::load_user_task(const char* filename)
     new_task->task_sleep = 0;
     new_task->task_time = 0;
     new_task->cpu_time = 0;
-    end_task->next_task = new_task;
+    strlcpy(new_task->name, filename, sizeof(new_task->name));
-    new_task->prev_task = end_task;
+    append_task(new_task);
-    base_task->prev_task = new_task;
-    new_task->next_task = base_task;
-    end_task = new_task;
     new_task->state = new_task->Running;
     task_num++;
-    kinfoln("Adding user task: loaded at %lx, tid %ld, stack at %lx, total tasks: %ld", new_task->regs.rip,
+    kinfoln("Adding user task: %s, loaded at %lx, PID %ld, stack at %lx, total tasks: %ld", new_task->name,
-            new_task->id, new_task->regs.rsp, task_num);
+            new_task->regs.rip, new_task->id, new_task->regs.rsp, task_num);
     VMM::switch_back_to_kernel_address_space();
     Interrupts::pop();
+    return (long)new_task->id;
 }
 
 void Scheduler::reset_task(Task* task, ELFImage* new_image)
@@ -168,8 +210,8 @@ void Scheduler::reset_task(Task* task, ELFImage* new_image)
     task->regs.rflags = (1 << 21) | (1 << 9); // enable interrupts
     task->task_sleep = 0;
     task->cpu_time = 0;
-    kinfoln("Resetting task: loaded at %lx, tid %ld, stack at %lx, total tasks: %ld", task->regs.rip, task->id,
+    kinfoln("Resetting task: %s, loaded at %lx, PID %ld, stack at %lx, total tasks: %ld", task->name, task->regs.rip,
-            task->regs.rsp, task_num);
+            task->id, task->regs.rsp, task_num);
 }
 
 void Scheduler::reap_task(Task* task)
@@ -184,8 +226,9 @@ void Scheduler::reap_task(Task* task)
         VMM::apply_address_space();
         VMM::switch_to_user_address_space(exiting_task->address_space);
     }
-    kinfoln("reaping task %ld, exited with code %ld", exiting_task->id, exiting_task->exit_status);
+    kinfoln("reaping task %s, PID %ld, exited with code %ld", exiting_task->name, exiting_task->id,
-    if (exiting_task->allocated_stack)
+            exiting_task->exit_status);
+    if (exiting_task->allocated_stack && !exiting_task->is_user_task())
         MemoryManager::release_pages((void*)exiting_task->allocated_stack, TASK_PAGES_IN_STACK);
     if (exiting_task->image) // FIXME: Also free pages the task has mmap-ed but not munmap-ed.
     {
@@ -194,6 +237,7 @@ void Scheduler::reap_task(Task* task)
     }
     if (exiting_task->is_user_task())
     {
+        exiting_task->allocator.free();
         VMM::switch_back_to_kernel_address_space();
         VMM::apply_address_space();
         Interrupts::push_and_enable();
@@ -276,17 +320,15 @@ void Scheduler::reap_tasks()
 
 static void sched_decrement_sleep_times()
 {
-    Task* task = base_task;
+    sched_for_each_task([](Task* task) {
-    if (!task) return;
-    do {
         if (task->task_sleep > 0)
         {
             task->task_sleep -= frequency;
             if (task->task_sleep < 0) task->task_sleep = 0;
         }
         if (task->task_sleep == 0 && task->state == task->Sleeping) task->state = task->Running;
-        task = task->next_task;
+        return true;
-    } while (task != base_task);
+    });
 }
 
 void Scheduler::task_tick(Context* context)
@@ -309,7 +351,7 @@ void Scheduler::task_yield(Context* context)
 {
     ASSERT(Interrupts::is_in_handler());
     Interrupts::disable();
-    get_context_to_task(*sched_current_task, context);
+    sched_current_task->save_context(context);
     bool was_idle = false;
     if (sched_current_task->state == sched_current_task->Idle)
     {
@@ -323,15 +365,14 @@ void Scheduler::task_yield(Context* context)
         {
             if (sched_current_task->id != original_task->id || was_idle)
             {
-                if (!was_idle && original_task->is_user_task() && original_task->state != original_task->Exited)
+                if (!was_idle && original_task->is_user_task() && !original_task->has_died())
                 {
-                    task_save_floating(*original_task);
+                    original_task->save_floating();
                 }
                 if (sched_current_task->is_user_task())
                 {
-                    VMM::switch_to_user_address_space(sched_current_task->address_space);
+                    sched_current_task->switch_to_address_space();
-                    VMM::apply_address_space();
+                    sched_current_task->restore_floating();
-                    task_restore_floating(*sched_current_task);
                 }
                 else if (!was_idle && original_task->is_user_task() && !sched_current_task->is_user_task())
                 {
@@ -340,17 +381,17 @@ void Scheduler::task_yield(Context* context)
                 }
             }
             sched_current_task->task_time = 20;
-            set_context_from_task(*sched_current_task, context);
+            sched_current_task->restore_context(context);
             return;
         }
     } while (sched_current_task != original_task);
     if (!was_idle && original_task->is_user_task() && original_task->state != original_task->Exited)
     {
-        task_save_floating(*original_task);
+        original_task->save_floating();
     }
     sched_current_task = &idle_task;
     sched_current_task->task_time = frequency;
-    if (!was_idle) { set_context_from_task(*sched_current_task, context); }
+    if (!was_idle) { sched_current_task->restore_context(context); }
     return;
 }
 

kernel/src/thread/Task.cpp

@@ -1,29 +1,68 @@
 #include "thread/Task.h"
+#include "memory/VMM.h"
 #include "std/string.h"
 
-void set_context_from_task(Task& task, Context* ctx)
+void Task::restore_context(Context* context)
 {
-    memcpy(ctx, &task.regs, sizeof(Context));
+    memcpy(context, &regs, sizeof(Context));
 }
 
-void get_context_to_task(Task& task, Context* ctx)
+void Task::save_context(Context* context)
 {
-    memcpy(&task.regs, ctx, sizeof(Context));
+    memcpy(&regs, context, sizeof(Context));
 }
 
-void task_save_floating(Task& task)
+void Task::save_floating()
 {
-    task.floating_saved = true;
+    floating_saved = true;
-    asm volatile("fxsave (%0)" : : "r"(&task.floating_region));
+    asm volatile("fxsave (%0)" : : "r"((char*)floating_region));
 }
 
-void task_restore_floating(Task& task)
+void Task::restore_floating()
 {
-    if (!task.floating_saved) return;
+    if (!floating_saved) return;
-    asm volatile("fxrstor (%0)" : : "r"(&task.floating_region));
+    asm volatile("fxrstor (%0)" : : "r"((char*)floating_region));
 }
 
 bool Task::is_user_task()
 {
     return user_task;
+}
+
+int Task::alloc_fd()
+{
+    int fd;
+    for (fd = 0; fd < TASK_MAX_FDS; fd++)
+    {
+        if (!files[fd].is_open()) break;
+    }
+
+    if (fd == TASK_MAX_FDS) { return -1; }
+
+    return fd;
+}
+
+int Task::alloc_fd_greater_than_or_equal(int base_fd)
+{
+    int fd;
+    if (base_fd >= TASK_MAX_FDS) return -1;
+    for (fd = base_fd; fd < TASK_MAX_FDS; fd++)
+    {
+        if (!files[fd].is_open()) break;
+    }
+
+    if (fd == TASK_MAX_FDS) { return -1; }
+
+    return fd;
+}
+
+void Task::switch_to_address_space()
+{
+    VMM::switch_to_user_address_space(address_space);
+    VMM::apply_address_space();
+}
+
+bool Task::has_died()
+{
+    return state == Exited;
 }

kernel/src/trace/Resolve.cpp

@@ -17,10 +17,10 @@ static size_t symbol_strlen(const char* symbol)
     return (i - symbol);
 }
 
-void get_symbol_name(uintptr_t address, char* buffer)
+void get_symbol_name(uintptr_t address, char* buffer, size_t max)
 {
     if (symbol_map.addr == (void*)-1) { symbol_map = InitRD::open("sys/moon.sym"); }
-    if (!symbol_map.addr) { strncpy(buffer, "(no symbols loaded)", 20); }
+    if (!symbol_map.addr) { strlcpy(buffer, "(no symbols loaded)", max); }
     while (address >= (uintptr_t)&kernel_start && address <= (uintptr_t)&kernel_end)
     {
         char addr_as_str[60];
@@ -30,11 +30,12 @@ void get_symbol_name(uintptr_t address, char* buffer)
         {
             symbol += 19;
             size_t symlen = symbol_strlen(symbol);
-            memcpy(buffer, symbol, symlen);
+            size_t copylen = (max - 1) < symlen ? (max - 1) : symlen;
-            buffer[symlen] = 0;
+            memcpy(buffer, symbol, copylen);
+            buffer[copylen] = 0;
             return;
         }
         address--;
     }
-    strncpy(buffer, "(no symbol)", 12);
+    strlcpy(buffer, "(no symbol)", max);
 }

kernel/src/trace/StackTracer.cpp

@@ -1,4 +1,7 @@
+#define MODULE "trace"
+
 #include "trace/StackTracer.h"
+#include "log/Log.h"
 #include "memory/Memory.h"
 #include "std/stdio.h"
 #include "trace/Resolve.h"
@@ -21,11 +24,11 @@ typedef struct stackframe
 void StackTracer::trace()
 {
     stackframe* frame = (stackframe*)m_base_pointer;
-    while (frame)
+    while (frame && frame->instruction)
     {
         char symbol_name[512];
-        get_symbol_name(frame->instruction, symbol_name);
+        get_symbol_name(frame->instruction - sizeof(uintptr_t), symbol_name, sizeof(symbol_name));
-        printf("%lx: %s\n", frame->instruction, symbol_name);
+        kinfoln("%lx: %s", frame->instruction - sizeof(uintptr_t), symbol_name);
         frame = frame->next;
     }
 }
@@ -33,8 +36,8 @@ void StackTracer::trace()
 void StackTracer::trace_with_ip(uintptr_t ip)
 {
     char symbol_name[512];
-    get_symbol_name(ip, symbol_name);
+    get_symbol_name(ip, symbol_name, sizeof(symbol_name));
-    printf("%lx: %s\n", ip, symbol_name);
+    kinfoln("%lx: %s", ip, symbol_name);
     trace();
 }
 

libs/libc/include/assert.h

@@ -0,0 +1,24 @@
+#ifndef _ASSERT_H
+#define _ASSERT_H
+
+#include <bits/macros.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    __lc_noreturn bool __assertion_failed(const char* file, int line, const char* function, const char* expr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef NDEBUG
+#define assert(expr) (void)0
+#else
+#define assert(expr) (bool)(expr) || __assertion_failed(__FILE__, __LINE__, __FUNCTION__, #expr)
+#endif
+
+#endif

libs/libc/include/bits/macros.h

@@ -1,8 +1,9 @@
 #ifndef _BITS_MACROS_H
 #define _BITS_MACROS_H
 
-#define noreturn __attribute__((noreturn))
+#define __lc_noreturn __attribute__((noreturn))
-#define align(n) __attribute__((aligned(n)))
+#define __lc_align(n) __attribute__((aligned(n)))
-#define deprecated(msg) __attribute__((deprecated(msg)))
+#define __lc_deprecated(msg) __attribute__((deprecated(msg)))
+#define __lc_unreachable __builtin_unreachable
 
 #endif

libs/libc/include/ctype.h

@@ -0,0 +1,58 @@
+#ifndef _CTYPE_H
+#define _CTYPE_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Is this character alphanumeric? */
+    int isalnum(int c);
+
+    /* Is this character a letter? */
+    int isalpha(int c);
+
+    /* Is this character part of ASCII? */
+    int isascii(int c);
+
+    /* Is this character a blank character (space or tab)? */
+    int isblank(int c);
+
+    /* Is this character a control character? */
+    int iscntrl(int c);
+
+    /* Is this character a digit? */
+    int isdigit(int c);
+
+    /* Is this character any printable character except space? */
+    int isgraph(int c);
+
+    /* Is this character a lowercase letter? */
+    int islower(int c);
+
+    /* Is this character any printable character (including space)? */
+    int isprint(int c);
+
+    /* Is this character any printable character which is not a space or an alphanumeric character? */
+    int ispunct(int c);
+
+    /* Is this character any space character (space, form feed, newline, carriage return, tab, vertical tab)? */
+    int isspace(int c);
+
+    /* Is this character an uppercase letter? */
+    int isupper(int c);
+
+    /* Is this character a hexadecimal digit (0-9, a-f, A-F)? */
+    int isxdigit(int c);
+
+    /* Returns the lowercase form of the specified character. */
+    int tolower(int c);
+
+    /* Returns the uppercase form of the specified character. */
+    int toupper(int c);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/errno.h

@@ -4,15 +4,20 @@
 /* The last error encountered during a call to a library or system function. */
 extern int errno;
 
-#define EPERM 1   // Operation not permitted
+#define EPERM 1    // Operation not permitted
-#define ENOENT 2  // No such file or directory
+#define ENOENT 2   // No such file or directory
-#define ENOEXEC 8 // Exec format error
+#define ENOEXEC 8  // Exec format error
-#define EBADF 9   // Bad file descriptor
+#define EBADF 9    // Bad file descriptor
-#define ENOMEM 12 // Cannot allocate memory
+#define ENOMEM 12  // Cannot allocate memory
-#define EFAULT 14 // Bad address
+#define EFAULT 14  // Bad address
-#define EISDIR 21 // Is a directory
+#define EEXIST 17  // File exists
-#define EINVAL 22 // Invalid argument
+#define ENOTDIR 20 // Not a directory
-#define EMFILE 24 // Too many open files
+#define EISDIR 21  // Is a directory
-#define ENOSYS 38 // Function not implemented
+#define EINVAL 22  // Invalid argument
+#define EMFILE 24  // Too many open files
+#define ENOSPC 28  // No space left on device
+#define EPIPE 32   // Broken pipe. Not implemented.
+#define ENOSYS 38  // Function not implemented
+#define ENOTSUP 95 // Operation not supported.
 
 #endif

libs/libc/include/fcntl.h

@@ -8,6 +8,9 @@
 /* Open for reading and writing. */
 #define O_RDWR 3
 
+/* Duplicate a file descriptor. */
+#define F_DUPFD 0
+
 #ifdef __cplusplus
 extern "C"
 {
@@ -16,6 +19,9 @@ extern "C"
     /* Opens the file specified by pathname. Returns a file descriptor on success, or -1 on error. */
     int open(const char* pathname, int flags);
 
+    /* Performs an operation on the file descriptor fd determined by cmd. */
+    int fcntl(int fd, int cmd, ...);
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/include/inttypes.h

@@ -0,0 +1,63 @@
+#ifndef _INTTYPES_H
+#define _INTTYPES_H
+
+#include <stdint.h>
+
+#define PRId8 "%d"
+#define PRId16 "%d"
+#define PRId32 "%d"
+#define PRId64 "%ld"
+#define PRIdLEAST8 "%d"
+#define PRIdLEAST16 "%d"
+#define PRIdLEAST32 "%d"
+#define PRIdLEAST64 "%ld"
+#define PRIdFAST8 "%d"
+#define PRIdFAST16 "%d"
+#define PRIdFAST32 "%d"
+#define PRIdFAST64 "%ld"
+#define PRIdMAX "%ld"
+#define PRIdPTR "%ld"
+#define PRIi8 "%d"
+#define PRIi16 "%d"
+#define PRIi32 "%d"
+#define PRIi64 "%ld"
+#define PRIiLEAST8 "%d"
+#define PRIiLEAST16 "%d"
+#define PRIiLEAST32 "%d"
+#define PRIiLEAST64 "%ld"
+#define PRIiFAST8 "%d"
+#define PRIiFAST16 "%d"
+#define PRIiFAST32 "%d"
+#define PRIiFAST64 "%ld"
+#define PRIiMAX "%ld"
+#define PRIiPTR "%ld"
+#define PRIu8 "%u"
+#define PRIu16 "%u"
+#define PRIu32 "%u"
+#define PRIu64 "%lu"
+#define PRIuLEAST8 "%u"
+#define PRIuLEAST16 "%u"
+#define PRIuLEAST32 "%u"
+#define PRIuLEAST64 "%lu"
+#define PRIuFAST8 "%u"
+#define PRIuFAST16 "%u"
+#define PRIuFAST32 "%u"
+#define PRIuFAST64 "%lu"
+#define PRIuMAX "%lu"
+#define PRIuPTR "%lu"
+#define PRIx8 "%x"
+#define PRIx16 "%x"
+#define PRIx32 "%x"
+#define PRIx64 "%lx"
+#define PRIxLEAST8 "%x"
+#define PRIxLEAST16 "%x"
+#define PRIxLEAST32 "%x"
+#define PRIxLEAST64 "%lx"
+#define PRIxFAST8 "%x"
+#define PRIxFAST16 "%x"
+#define PRIxFAST32 "%x"
+#define PRIxFAST64 "%lx"
+#define PRIxMAX "%lx"
+#define PRIxPTR "%lx"
+
+#endif

libs/libc/include/libgen.h

@@ -0,0 +1,21 @@
+#ifndef _LIBGEN_H
+#define _LIBGEN_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Returns the last component of a path. This function is allowed to modify the string passed to it, so it should
+     * probably be a copy of another string. */
+    char* basename(char* path);
+
+    /* Returns the parent directory of a path. This function is allowed to modify the string passed to it, so it should
+     * probably be a copy of another string. */
+    char* dirname(char* path);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/luna.h

@@ -9,14 +9,11 @@ extern "C"
 {
 #endif
 
-    /* Returns the current program's thread identifier. */
-    pid_t gettid();
-
     /* Sleeps for ms milliseconds. */
     unsigned int msleep(unsigned int ms);
 
     /* Prints a message to standard error and aborts the program. */
-    noreturn void __luna_abort(const char* message);
+    __lc_noreturn void __luna_abort(const char* message);
 
 #ifdef __cplusplus
 }

libs/libc/include/luna/os-limits.h

@@ -0,0 +1,10 @@
+#ifndef _LUNA_OS_LIMITS_H
+#define _LUNA_OS_LIMITS_H
+
+#define OPEN_MAX 32
+#define ATEXIT_MAX 32
+
+#define PAGESIZE 4096
+#define PAGE_SIZE 4096
+
+#endif

libs/libc/include/luna/syscall.h

@@ -6,15 +6,19 @@
 #define SYS_sleep 2
 #define SYS_write 3
 #define SYS_paint 4
-#define SYS_rand 5
+#define SYS_getpid 5
-#define SYS_gettid 6
+#define SYS_mmap 6
-#define SYS_mmap 7
+#define SYS_munmap 7
-#define SYS_munmap 8
+#define SYS_open 8
-#define SYS_open 9
+#define SYS_read 9
-#define SYS_read 10
+#define SYS_close 10
-#define SYS_close 11
+#define SYS_seek 11
-#define SYS_seek 12
+#define SYS_exec 12
-#define SYS_exec 13
+#define SYS_fcntl 13
+#define SYS_mprotect 14
+#define SYS_clock 15
+#define SYS_mkdir 16
+#define SYS_fork 17
 
 #ifndef __want_syscalls
 #ifdef __cplusplus

libs/libc/include/sched.h

@@ -0,0 +1,16 @@
+#ifndef _SCHED_H
+#define _SCHED_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Yield the processor. */
+    int sched_yield(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/setjmp.h

@@ -0,0 +1,32 @@
+#ifndef _SETJMP_H
+#define _SETJMP_H
+
+#include <bits/macros.h>
+#include <stdint.h>
+
+typedef uintptr_t jmp_buf[8];
+typedef uintptr_t sigjmp_buf[8];
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Saves the current execution state in env. Returns 0 when called from the first time, or nonzero when returning
+     * from longjmp.  */
+    int setjmp(jmp_buf env);
+
+    /* Right now, does the exact same as setjmp() (savesigs is ignored), since signals are not implemented. */
+    int sigsetjmp(sigjmp_buf env, int savesigs);
+
+    /* Restores the execution state saved in env by a setjmp() call. */
+    __lc_noreturn void longjmp(jmp_buf env, int val);
+
+    /* Right now, does the exact same as longjmp(), since signals are not implemented. */
+    __lc_noreturn void siglongjmp(sigjmp_buf env, int val);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/signal.h

@@ -0,0 +1,7 @@
+#ifndef _SIGNAL_H
+#define _SIGNAL_H
+
+typedef int sig_atomic_t; // FIXME: Implement signals (I'm trying to build bc, this header is only to satisfy it) and
+                          // use a proper atomic integer type.
+
+#endif

libs/libc/include/stdio.h

@@ -6,6 +6,8 @@
 
 #include <bits/seek.h>
 
+#define FOPEN_MAX 32
+
 typedef struct
 {
     int f_fd;
@@ -40,6 +42,9 @@ extern "C"
     /* Returns a new file associated with the file descriptor fd. */
     FILE* fdopen(int fd, const char* mode);
 
+    /* Returns the file descriptor associated with the file stream. */
+    int fileno(FILE* stream);
+
     /* Writes formatted output according to the string format to the file stream. */
     int fprintf(FILE* stream, const char* format, ...);
 

libs/libc/include/stdlib.h

@@ -10,16 +10,25 @@ extern "C"
 #endif
 
     /* Aborts the program. */
-    noreturn void abort();
+    __lc_noreturn void abort(void);
 
     /* Normally exits the program with the specified status code. */
-    noreturn void exit(int status);
+    __lc_noreturn void exit(int status);
+
+    /* Abnormally exits the program with the specified status code. */
+    __lc_noreturn void _Exit(int status);
 
     /* Registers a handler function to be run at normal program termination. */
     int atexit(void (*handler)(void));
 
-    /* Not implemented.*/
+    /* Returns an integer (of type int) parsed from the string str. */
-    int atoi(const char*);
+    int atoi(const char* str);
+
+    /* Returns an integer (of type long) parsed from the string str. */
+    long atol(const char* str);
+
+    /* Returns an integer (of type long long) parsed from the string str. */
+    long long atoll(const char* str);
 
     /* Not implemented. */
     char* getenv(const char*);
@@ -41,6 +50,12 @@ extern "C"
      * is undefined behavior. */
     void free(void* ptr);
 
+    /* Returns a random number. */
+    int rand(void);
+
+    /* Seeds the random number generator with the specified seed. */
+    void srand(unsigned int seed);
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/include/string.h

@@ -15,15 +15,26 @@ extern "C"
     /* Sets n bytes of buf to c, cast to a character. */
     void* memset(void* buf, int c, size_t n);
 
-    /* Clears n bytes of buf. */
+    /* Searches for the character c in n bytes of buf. */
-    void* memclr(void* buf, size_t n);
+    void* memchr(const void* buf, int c, size_t n);
+
+    /* Compares n bytes of memory at a and b. */
+    int memcmp(const void* a, const void* b, size_t n);
+
+    /* Copies n bytes from src to dst. Can be used if src and dst overlap. */
+    void* memmove(void* dest, const void* src, size_t n);
+
+    /* Returns a heap-allocated copy of the string str. Should be freed when it is not used anymore. */
+    char* strdup(const char* str);
 
     /* Returns the length of the string str. */
     size_t strlen(const char* str);
 
-    /* Copies the string src into dest. This function is unsafe, use strncpy instead. */
+    /* Returns the length of the string str, while examining at most max bytes of str. */
-    deprecated("strcpy is unsafe and should not be used; use strncpy instead") char* strcpy(char* dest,
+    size_t strnlen(const char* str, size_t max);
-                                                                                            const char* src);
+
+    /* Copies at most size-1 bytes from the string src into dest, null-terminating the result. */
+    size_t strlcpy(char* dst, const char* src, size_t size);
 
     /* Copies at most max bytes from the string src into dest. */
     char* strncpy(char* dest, const char* src, size_t max);
@@ -31,16 +42,35 @@ extern "C"
     /* Returns a pointer to the first occurrence of the character c in str, or NULL if it is not found. */
     char* strchr(const char* str, int c);
 
-    /* Concatenates the string src into dest. This function is unsafe, use strncat instead. */
+    /* Returns a pointer to the last occurrence of the character c in str, or NULL if it is not found. */
-    deprecated("strcat is unsafe and should not be used; use strncat instead") char* strcat(char* dest,
+    char* strrchr(const char* str, int c);
-                                                                                            const char* src);
 
     /* Concatenates at most max bytes of the string src into dest. */
     char* strncat(char* dest, const char* src, size_t max);
 
+    /* Compares strings a and b. You might prefer to use the safer strncmp function. */
+    int strcmp(const char* a, const char* b);
+
+    /* Compares at most max bytes of the strings a and b. */
+    int strncmp(const char* a, const char* b, size_t max);
+
+    /* Searches for the needle string in the haystack string. */
+    char* strstr(const char* haystack, const char* needle);
+
     /* Returns the error string associated with the error number err. */
     char* strerror(int err);
 
+    /* Clears n bytes of buf. */
+    void* bzero(void* buf, size_t n);
+
+    /* Copies the string src into dest. This function is unsafe, use strlcpy instead. */
+    __lc_deprecated("strcpy is unsafe and should not be used; use strlcpy instead") char* strcpy(char* dest,
+                                                                                                 const char* src);
+
+    /* Concatenates the string src into dest. This function is unsafe, use strncat instead. */
+    __lc_deprecated("strcat is unsafe and should not be used; use strncat instead") char* strcat(char* dest,
+                                                                                                 const char* src);
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/include/sys/mman.h

@@ -7,7 +7,9 @@
 /* Address returned by mmap when it fails. */
 #define MAP_FAILED (void*)-1
 
-#define PROT_READ_WRITE 1
+#define PROT_NONE 0
+#define PROT_READ 1
+#define PROT_WRITE 2
 
 #define PAGE_SIZE 4096
 
@@ -24,6 +26,9 @@ extern "C"
      * address space. */
     int munmap(void* addr, size_t size);
 
+    /* Protects size bytes of memory according to the prot argument. */
+    int mprotect(void* addr, size_t size, int prot);
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/include/sys/stat.h

@@ -0,0 +1,18 @@
+#ifndef _SYS_STAT_H
+#define _SYS_STAT_H
+
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Creates a new directory at the path pathname. FIXME: For now, mode is ignored. */
+    int mkdir(const char* pathname, mode_t mode);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/sys/types.h

@@ -13,4 +13,7 @@ typedef long int ssize_t;
 /* The type of an offset into a file. */
 typedef long int off_t;
 
+/* The type of a file's mode. */
+typedef unsigned short mode_t;
+
 #endif

libs/libc/include/time.h

@@ -0,0 +1,22 @@
+#ifndef _TIME_H
+#define _TIME_H
+
+typedef long int clock_t;
+typedef long int time_t;
+
+#define CLOCKS_PER_SEC 1000
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Returns a number representing how much CPU time has been used by this process. Divide this by CLOCKS_PER_SEC to
+     * get the value in seconds. */
+    clock_t clock(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/unistd.h

@@ -3,8 +3,12 @@
 
 #include <bits/macros.h>
 #include <bits/seek.h>
+#include <luna/os-limits.h>
 #include <sys/types.h>
 
+#define STDOUT_FILENO 0
+#define STDERR_FILENO 1
+
 #ifdef __cplusplus
 extern "C"
 {
@@ -18,11 +22,16 @@ extern "C"
     int execve(const char*, char* const[], char* const[]);
     /* Not implemented. */
     int execvp(const char*, char* const[]);
-    /* Not implemented. */
+
+    /* Creates an identical copy (child) of the current process (parent). Returns 0 to the child, and the child's PID to
+     * the parent. */
     pid_t fork(void);
 
+    /* Returns the current process's process ID. */
+    pid_t getpid(void);
+
     /* Terminates the program with the status code status. */
-    noreturn void _exit(int status);
+    __lc_noreturn void _exit(int status);
 
     /* Calls the kernel for a specific service, determined by number. */
     long syscall(long number, ...);
@@ -42,6 +51,9 @@ extern "C"
     /* Moves the read/write file offset for fd to offset, depending on whence. */
     off_t lseek(int fd, off_t offset, int whence);
 
+    /* Returns a copy of the file descriptor fd. */
+    int dup(int fd);
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/src/assert.cpp

@@ -0,0 +1,12 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern "C"
+{
+    __lc_noreturn bool __assertion_failed(const char* file, int line, const char* function, const char* expr)
+    {
+        fprintf(stderr, "%s:%d: %s: Assertion '%s' failed.", file, line, function, expr);
+        abort();
+    }
+}

libs/libc/src/atexit.cpp

@@ -17,7 +17,7 @@ extern "C"
         return 0;
     }
 
-    noreturn void exit(int status)
+    __lc_noreturn void exit(int status)
     {
         for (int i = 0; i < atexit_function_count; i++) { atexit_functions[i](); }
         _exit(status);

libs/libc/src/bits/bindings.c

@@ -13,7 +13,7 @@ int liballoc_unlock()
 
 void* liballoc_alloc(size_t size)
 {
-    void* result = mmap(NULL, size * PAGE_SIZE, PROT_READ_WRITE, 0, 0, 0);
+    void* result = mmap(NULL, size * PAGE_SIZE, PROT_READ | PROT_WRITE, 0, 0, 0);
     if (result == MAP_FAILED) return 0;
     return (void*)result;
 }

libs/libc/src/ctype.cpp

@@ -0,0 +1,81 @@
+#include <ctype.h>
+
+extern "C"
+{
+    int isalnum(int c)
+    {
+        return isalpha(c) || isdigit(c);
+    }
+
+    int isalpha(int c)
+    {
+        return islower(c) || isupper(c);
+    }
+
+    int isascii(int c)
+    {
+        return !(c & ~0x7f);
+    }
+
+    int isblank(int c)
+    {
+        return c == ' ' || c == '\t';
+    }
+
+    int iscntrl(int c)
+    {
+        return (unsigned int)c < 0x20 || c == 0x7f;
+    }
+
+    int isdigit(int c)
+    {
+        return c >= '0' && c < ':';
+    }
+
+    int isgraph(int c)
+    {
+        return (unsigned int)c - 0x21 < 0x5e;
+    }
+
+    int islower(int c)
+    {
+        return c >= 'a' && c < '{';
+    }
+
+    int isprint(int c)
+    {
+        return (unsigned int)c - 0x20 < 0x5f;
+    }
+
+    int ispunct(int c)
+    {
+        return isgraph(c) && !isalnum(c);
+    }
+
+    int isspace(int c)
+    {
+        return c == ' ' || (unsigned int)c - '\t' < 5;
+    }
+
+    int isupper(int c)
+    {
+        return c >= 'A' && c < '[';
+    }
+
+    int isxdigit(int c)
+    {
+        return isdigit(c) || ((unsigned int)c | 32) - 'a' < 6;
+    }
+
+    int tolower(int c)
+    {
+        if (isupper(c)) return c | 32;
+        return c;
+    }
+
+    int toupper(int c)
+    {
+        if (islower(c)) return c & 0x5f;
+        return c;
+    }
+}

libs/libc/src/fcntl.cpp

@@ -1,4 +1,6 @@
 #include <fcntl.h>
+#include <stdarg.h>
+#include <stdint.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 
@@ -8,4 +10,13 @@ extern "C"
     {
         return (int)syscall(SYS_open, pathname, flags);
     }
+
+    int fcntl(int fd, int cmd, ...)
+    {
+        va_list ap;
+        va_start(ap, cmd);
+        long result = syscall(SYS_fcntl, fd, cmd, va_arg(ap, uintptr_t));
+        va_end(ap);
+        return (int)result;
+    }
 }

libs/libc/src/file.cpp

@@ -30,14 +30,11 @@ extern "C"
         return 0; // FIXME: Implement buffered IO.
     }
 
-    FILE* fopen(const char* pathname, const char*)
+    FILE* fopen(const char* pathname, const char* mode)
     {
         int fd = open(pathname, O_RDWR); // FIXME: Use the mode string.
         if (fd < 0) { return 0; }
-        FILE* stream = (FILE*)malloc(sizeof(FILE));
+        return fdopen(fd, mode);
-        stream->f_fd = fd;
-        clearerr(stream);
-        return stream;
     }
 
     FILE* fdopen(int fd, const char*)
@@ -48,11 +45,17 @@ extern "C"
             return 0;
         }
         FILE* stream = (FILE*)malloc(sizeof(FILE));
+        if (!stream) { return 0; }
         stream->f_fd = fd;
         clearerr(stream);
         return stream;
     }
 
+    int fileno(FILE* stream)
+    {
+        return stream->f_fd;
+    }
+
     size_t fread(void* buf, size_t size, size_t nmemb, FILE* stream)
     {
         ssize_t status = read(stream->f_fd, buf, size * nmemb);

libs/libc/src/init.cpp

@@ -10,14 +10,41 @@ static void terminate_libc()
     fclose(stderr);
 }
 
+static void initialize_random()
+{
+    unsigned int seed = 3735928559U;
+
+    FILE* fp = fopen("/dev/random", "rw");
+    if (!fp)
+    {
+        errno = 0;
+        goto failed_to_read_dev_random;
+    }
+
+    fread(&seed, sizeof(seed), 1, fp);
+    if (ferror(fp))
+    {
+        errno = 0;
+        fclose(fp);
+        goto failed_to_read_dev_random;
+    }
+
+    fclose(fp);
+
+failed_to_read_dev_random:
+    srand(seed); // If we failed, this will be seeded with a known value. Else, it will be seeded with a random value
+                 // from the kernel.
+    return;
+}
+
 static void check_for_file(int fd, FILE** target_stream, const char* path, const char* mode)
 {
     if (lseek(fd, 0, SEEK_CUR) < 0)
     {
         if (errno == EBADF) *target_stream = fopen(path, mode);
         else
-            exit(errno);
+            exit(-127);
-        if (!*target_stream) exit(errno);
+        if (!*target_stream) exit(-127);
         errno = 0;
     }
     else { *target_stream = fdopen(fd, mode); }
@@ -25,7 +52,9 @@ static void check_for_file(int fd, FILE** target_stream, const char* path, const
 
 extern "C" void initialize_libc()
 {
-    check_for_file(0, &stdout, "/dev/console", "rw");
+    check_for_file(STDOUT_FILENO, &stdout, "/dev/console", "rw");
-    check_for_file(1, &stderr, "/dev/console", "rw");
+    check_for_file(STDERR_FILENO, &stderr, "/dev/console", "rw");
+
+    initialize_random();
     atexit(terminate_libc);
 }

libs/libc/src/libgen.cpp

@@ -0,0 +1,50 @@
+#include <libgen.h>
+#include <string.h>
+
+static char dot[] = ".";
+
+extern "C"
+{
+    char* basename(char* path)
+    {
+        // If path is NULL, or the string's length is 0, return .
+        if (!path) return dot;
+        size_t len = strlen(path);
+        if (!len) return dot;
+
+        // Strip trailing slashes.
+        char* it = path + len - 1;
+        while (*it == '/' && it != path) { it--; }
+        *(it + 1) = 0;
+        if (it == path) return path;
+
+        // Return path from the first character if there are no more slashes, or from the first character after the last
+        // slash.
+        char* beg = strrchr(path, '/');
+        if (!beg) return path;
+        return beg + 1;
+    }
+
+    char* dirname(char* path)
+    {
+        // If path is NULL, or the string's length is 0, return .
+        if (!path) return dot;
+        size_t len = strlen(path);
+        if (!len) return dot;
+
+        // Strip trailing slashes.
+        char* it = path + len - 1;
+        while (*it == '/' && it != path) { it--; }
+        *(char*)(it + 1) = 0;
+        if (it == path) return path;
+
+        // Search for the last slash. If there is none, return .
+        // Otherwise, we end the string there and return.
+        char* end = strrchr(path, '/');
+        if (!end) return dot;
+        if (end != path) *end = 0;
+        else
+            *(end + 1) = 0;
+        return path;
+    }
+}

libs/libc/src/luna.cpp

@@ -7,17 +7,12 @@
 
 extern "C"
 {
-    pid_t gettid()
-    {
-        return syscall(SYS_gettid);
-    }
-
     unsigned int msleep(unsigned int ms)
     {
         return (unsigned int)syscall(SYS_sleep, ms);
     }
 
-    noreturn void __luna_abort(const char* message)
+    __lc_noreturn void __luna_abort(const char* message)
     {
         fputs(message, stderr);
         abort();

libs/libc/src/rand.cpp

@@ -0,0 +1,64 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+typedef uint32_t word_t;
+#define STATE_SIZE 624
+#define MIDDLE 397
+#define INIT_SHIFT 30
+#define INIT_FACT 1812433253
+#define TWIST_MASK 0x9908b0df
+#define SHIFT1 11
+#define MASK1 0xffffffff
+#define SHIFT2 7
+#define MASK2 0x9d2c5680
+#define SHIFT3 15
+#define MASK3 0xefc60000
+#define SHIFT4 18
+
+#define LOWER_MASK 0x7fffffff
+#define UPPER_MASK (~(word_t)LOWER_MASK)
+
+static word_t state[STATE_SIZE];
+static size_t index = STATE_SIZE + 1;
+
+static void twist()
+{
+    for (size_t i = 0; i < STATE_SIZE; i++)
+    {
+        word_t x = (state[i] & UPPER_MASK) | (state[(i + 1) % STATE_SIZE] & LOWER_MASK);
+        x = (x >> 1) ^ (x & 1 ? TWIST_MASK : 0);
+        state[i] = state[(i + MIDDLE) % STATE_SIZE] ^ x;
+    }
+    index = 0;
+}
+
+extern "C"
+{
+    int rand()
+    {
+        if (index >= STATE_SIZE)
+        {
+            assert(index == STATE_SIZE && "Mersenne generator was never seeded");
+            twist();
+        }
+
+        word_t y = state[index];
+        y ^= (y >> SHIFT1) & MASK1;
+        y ^= (y << SHIFT2) & MASK2;
+        y ^= (y << SHIFT3) & MASK3;
+        y ^= y >> SHIFT4;
+
+        index++;
+        return y;
+    }
+
+    void srand(unsigned int seed)
+    {
+        index = STATE_SIZE;
+        state[0] = seed;
+        for (size_t i = 1; i < STATE_SIZE; i++)
+            state[i] = (word_t)((INIT_FACT * (state[i - 1] ^ (state[i - 1] >> INIT_SHIFT))) + i);
+    }
+}

libs/libc/src/sched.cpp

@@ -0,0 +1,11 @@
+#include <sched.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+extern "C"
+{
+    int sched_yield()
+    {
+        return (int)syscall(SYS_yield);
+    }
+}

libs/libc/src/setjmp.asm

@@ -0,0 +1,36 @@
+global _setjmp
+global setjmp
+_setjmp:
+setjmp:
+    mov rsi, 0
+    mov [rdi], rbx
+    mov [rdi+8], r12
+    mov [rdi+16], r13
+    mov [rdi+24], r14
+    mov [rdi+32], r15
+    mov [rdi+40], rbp 
+    mov [rdi+48], rsp
+    mov rax, [rsp]
+    mov [rdi+56], rax
+    xor rax, rax
+    ret
+
+global _longjmp
+global longjmp
+_longjmp:
+longjmp:
+    mov rax, rsi
+    cmp rax, 0
+    jne .nonzero
+    mov rax, 1
+.nonzero:
+    mov rbx, [rdi]
+    mov r12, [rdi+8]
+    mov r13, [rdi+16]
+    mov r14, [rdi+24]
+    mov r15, [rdi+32]
+    mov rbp, [rdi+40]
+    mov rsp, [rdi+48]
+    mov rcx, [rdi+56]
+    mov [rsp], rcx
+    ret

libs/libc/src/setjmp.cpp

@@ -0,0 +1,15 @@
+#include <luna.h>
+#include <setjmp.h>
+
+extern "C"
+{
+    int sigsetjmp(sigjmp_buf env, int)
+    {
+        return setjmp(env);
+    }
+
+    __lc_noreturn void siglongjmp(sigjmp_buf env, int val)
+    {
+        longjmp(env, val);
+    }
+}

libs/libc/src/stdlib.cpp

@@ -1,22 +1,59 @@
+#include <ctype.h>
 #include <luna.h>
 #include <stdlib.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 
-extern "C"
+template <typename T> T string_to_integer_type(const char* str)
 {
-    noreturn void abort()
+    bool neg = false;
+    T val = 0;
+
+    switch (*str)
     {
-        _exit(-1);
+    case '-':
+        neg = true;
+        str++;
+        break;
+    case '+': str++; break;
+    default: break;
     }
 
-    int atoi(const char*)
+    while (isdigit(*str)) { val = (10 * val) + (*str++ - '0'); }
+
+    return (neg ? -val : val);
+}
+
+extern "C"
+{
+    __lc_noreturn void abort()
     {
-        NOT_IMPLEMENTED("atoi");
+        _Exit(-1);
+    }
+
+    int atoi(const char* str)
+    {
+        return string_to_integer_type<int>(str);
+    }
+
+    long atol(const char* str)
+    {
+        return string_to_integer_type<long>(str);
+    }
+
+    long long atoll(const char* str)
+    {
+        return string_to_integer_type<long long>(str);
     }
 
     char* getenv(const char*)
     {
         NOT_IMPLEMENTED("getenv");
     }
+
+    __lc_noreturn void _Exit(int status)
+    {
+        syscall(SYS_exit, status);
+        __lc_unreachable();
+    }
 }

libs/libc/src/string.cpp

@@ -1,5 +1,5 @@
 #include <errno.h>
-#include <luna.h>
+#include <stdlib.h>
 #include <string.h>
 
 extern "C"
@@ -16,6 +16,44 @@ extern "C"
         return buf;
     }
 
+    void* memchr(const void* buf, int c, size_t n)
+    {
+        const char* s = (const char*)buf;
+        for (; n && *s != (char)c; s++, n--)
+            ;
+        if (n) return (void*)(const_cast<char*>(s));
+        return NULL;
+    }
+
+    int memcmp(const void* a, const void* b, size_t n)
+    {
+        const char* _a = (const char*)a;
+        const char* _b = (const char*)b;
+        for (; n && _a == _b; n--, _a++, _b++)
+            ;
+        if (!n) return 0;
+        if (*_a > *_b) return 1;
+        return -1;
+    }
+
+    void* memmove(void* dest, const void* src, size_t n)
+    {
+        if (dest == src) return dest;
+        if (dest > src)
+            for (long i = n - 1; i >= 0; i++) { *((char*)dest + i) = *((const char*)src + i); }
+        else
+            for (long i = 0; i < (long)n; i++) { *((char*)dest + i) = *((const char*)src + i); }
+        return dest;
+    }
+
+    char* strdup(const char* str)
+    {
+        size_t len = strlen(str);
+        char* dest = (char*)malloc(len + 1);
+        if (!dest) return dest;
+        return (char*)memcpy(dest, str, len + 1);
+    }
+
     size_t strlen(const char* str)
     {
         const char* i = str;
@@ -24,17 +62,61 @@ extern "C"
         return (i - str);
     }
 
+    size_t strnlen(const char* str, size_t max)
+    {
+        char* p = (char*)memchr(str, 0, max);
+        return p ? p - str : max;
+    }
+
     char* strcpy(char* dest, const char* src)
     {
-        memcpy(dest, src, strlen(src) + 1);
+        return (char*)memcpy(dest, src, strlen(src) + 1);
+    }
+
+    char* strncpy(char* dest, const char* src, size_t max)
+    {
+        size_t i;
+        for (i = 0; i < max && src[i] != 0; i++) dest[i] = src[i];
+        for (; i < max; i++) dest[i] = 0;
         return dest;
     }
 
-    char* strncpy(char* dest, const char* src, size_t max) // FIXME: Implement strncpy according to the specification.
+    size_t strlcpy(char* dest, const char* src, size_t size)
     {
-        size_t src_len = strlen(src) + 1; // NULL byte
+        size_t len = strlen(src);
-        memcpy(dest, src, src_len > max ? max : src_len);
+        if (size == 0) return len;
-        return dest;
+        if (len < (size - 1))
+        {
+            memcpy(dest, src, len);
+            dest[len] = 0;
+        }
+        else
+        {
+            memcpy(dest, src, size - 1);
+            dest[size - 1] = 0;
+        }
+        return len;
+    }
+
+    int strcmp(const char* a, const char* b)
+    {
+        while (*a && (*a == *b))
+        {
+            a++;
+            b++;
+        }
+        return *(const unsigned char*)a - *(const unsigned char*)b;
+    }
+
+    int strncmp(const char* a, const char* b, size_t max)
+    {
+        const char* base = a;
+        while (*a && (*a == *b) && (size_t)(a - base) < (max - 1))
+        {
+            a++;
+            b++;
+        }
+        return *(const unsigned char*)a - *(const unsigned char*)b;
     }
 
     char* strcat(char* dest, const char* src)
@@ -68,48 +150,38 @@ extern "C"
         return NULL;
     }
 
-    void* memclr(void* buf, size_t n)
+    char* strrchr(const char* str, int c)
     {
-        // "i" is our counter of how many bytes we've cleared
+        const char* s = str + strlen(str);
-        size_t i;
+        while (s != str && *s != (char)c) s--;
+        if (s != str) return const_cast<char*>(s);
+        if (*s == (char)c) return const_cast<char*>(s);
+        return NULL;
+    }
 
-        // find out if "m_start" is aligned on a SSE_XMM_SIZE boundary
+    void* bzero(void* buf, size_t n)
-        if ((size_t)buf & (15))
+    {
+        return memset(buf, 0, n);
+    }
+
+    char* strstr(const char* haystack, const char* needle)
+    {
+        size_t needle_size = strlen(needle);
+        size_t haystack_size = strlen(haystack);
+        while (*haystack)
         {
-            i = 0;
+            if (*haystack == *needle)
-
-            // we need to clear byte-by-byte until "m_start" is aligned on an SSE_XMM_SIZE boundary
-            // ... and lets make sure we don't copy 'too' many bytes (i < m_count)
-            while (((size_t)buf + i) & (15) && i < n)
             {
-                asm("stosb;" ::"D"((size_t)buf + i), "a"(0));
+                if (needle_size <= haystack_size)
-                i++;
+                {
+                    if (!strncmp(haystack, needle, needle_size)) return const_cast<char*>(haystack);
+                }
+                else { return NULL; }
             }
+            haystack++;
+            haystack_size--;
         }
-        else
+        return NULL;
-        {
-            // if "m_start" was aligned, set our count to 0
-            i = 0;
-        }
-
-        // clear 64-byte chunks of memory (4 16-byte operations)
-        for (; i + 64 <= n; i += 64)
-        {
-            asm volatile(" pxor %%xmm0, %%xmm0;	"     // set XMM0 to 0
-                         " movdqa %%xmm0, 0(%0);	" // move 16 bytes from XMM0 to %0 + 0
-                         " movdqa %%xmm0, 16(%0);	"
-                         " movdqa %%xmm0, 32(%0);	"
-                         " movdqa %%xmm0, 48(%0);	" ::"r"((size_t)buf + i));
-        }
-
-        // copy the remaining bytes (if any)
-        asm(" rep stosb; " ::"a"((size_t)(0)), "D"(((size_t)buf) + i), "c"(n - i));
-
-        // "i" will contain the total amount of bytes that were actually transfered
-        i += n - i;
-
-        // we return "m_start" + the amount of bytes that were transfered
-        return (void*)(((size_t)buf) + i);
     }
 
 #pragma GCC push_options
@@ -129,8 +201,13 @@ extern "C"
         case EISDIR: return "Is a directory";
         case ENOEXEC: return "Exec format error";
         case EFAULT: return "Bad address";
+        case EEXIST: return "File exists";
+        case ENOTDIR: return "Not a directory";
+        case ENOSPC: return "No space left on device";
+        case ENOTSUP: return "Operation not supported";
+        case EPIPE: return "Broken pipe";
         case 0: return "Success";
-        default: return (char*)(unsigned long int)err;
+        default: return "Unknown error";
         }
     }
 

libs/libc/src/sys/mman.cpp

@@ -14,4 +14,9 @@ extern "C"
     {
         return (int)syscall(SYS_munmap, addr, len);
     }
+
+    int mprotect(void* addr, size_t size, int prot)
+    {
+        return (int)syscall(SYS_mprotect, addr, size, prot);
+    }
 }

libs/libc/src/sys/stat.cpp

@@ -0,0 +1,11 @@
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+extern "C"
+{
+    int mkdir(const char* pathname, mode_t)
+    {
+        return (int)syscall(SYS_mkdir, pathname);
+    }
+}

libs/libc/src/time.cpp

@@ -0,0 +1,11 @@
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+
+extern "C"
+{
+    clock_t clock()
+    {
+        return syscall(SYS_clock);
+    }
+}

libs/libc/src/unistd.cpp

@@ -1,4 +1,5 @@
 #include <bits/error.h>
+#include <fcntl.h>
 #include <luna.h>
 #include <luna/syscall.h>
 #include <stdarg.h>
@@ -18,9 +19,15 @@ extern "C"
     {
         NOT_IMPLEMENTED("execvp");
     }
+
     pid_t fork(void)
     {
-        NOT_IMPLEMENTED("fork");
+        return syscall(SYS_fork);
+    }
+
+    pid_t getpid(void)
+    {
+        return syscall(SYS_getpid);
     }
 
     long syscall(long number, ...)
@@ -31,12 +38,14 @@ extern "C"
         va_start(ap, number);
         switch (number)
         {
+        case SYS_clock:
         case SYS_yield:
-        case SYS_gettid:
+        case SYS_fork:
-        case SYS_rand: result = __luna_syscall0(number); break;
+        case SYS_getpid: result = __luna_syscall0(number); break;
         case SYS_exit:
         case SYS_close:
         case SYS_exec:
+        case SYS_mkdir:
         case SYS_sleep: result = __luna_syscall1(number, va_arg(ap, arg)); break;
         case SYS_munmap:
         case SYS_open: {
@@ -45,9 +54,11 @@ extern "C"
             result = __luna_syscall2(number, arg0, arg1);
             break;
         }
+        case SYS_fcntl:
         case SYS_seek:
         case SYS_write:
         case SYS_read:
+        case SYS_mprotect:
         case SYS_mmap: {
             arg arg0 = va_arg(ap, arg);
             arg arg1 = va_arg(ap, arg);
@@ -96,9 +107,14 @@ extern "C"
         return syscall(SYS_seek, fd, offset, whence);
     }
 
-    noreturn void _exit(int status)
+    __lc_noreturn void _exit(int status)
     {
         syscall(SYS_exit, status);
-        __builtin_unreachable();
+        __lc_unreachable();
+    }
+
+    int dup(int fd)
+    {
+        return fcntl(fd, F_DUPFD, 0);
     }
 }

tests/Makefile

@@ -0,0 +1,9 @@
+build:
+	make -C libc build
+
+install:
+	make -C libc install
+
+test:
+	make -C libc test
+	

tests/Test.h

@@ -0,0 +1,39 @@
+#ifndef __TEST_H_
+#define __TEST_H_
+#include <stdbool.h>
+
+int printf(const char*, ...);
+
+#define DEFINE_TEST(name) bool test_##name()
+#define START_TEST(name) printf("testing whether %s works... ", #name)
+#define START_TEST_CASE(name) printf("testing %s...\n", #name)
+
+#define TEST_SUCCESS()                                                                                                 \
+    do {                                                                                                               \
+        printf("yes!\n");                                                                                              \
+        return true;                                                                                                   \
+    } while (0)
+
+#define TEST_FAIL(expr)                                                                                                \
+    do {                                                                                                               \
+        printf("no (%s)\n", #expr);                                                                                    \
+        return false;                                                                                                  \
+    } while (0)
+
+#define EXPECT(expr)                                                                                                   \
+    do {                                                                                                               \
+        if (!(expr)) { TEST_FAIL(expr); }                                                                              \
+    } while (0)
+
+#define EXPECT_EQ(a, b) EXPECT((a) == (b))
+
+#define EXPECT_NOT_EQ(a, b) EXPECT((a) != (b))
+
+#define EXPECT_NOT_CRASHED() TEST_SUCCESS()
+
+#define RUN_TEST(name)                                                                                                 \
+    do {                                                                                                               \
+        if (!test_##name()) return 1;                                                                                  \
+    } while (0)
+
+#endif

tests/libc/Makefile

@@ -0,0 +1,15 @@
+TESTDIR := $(LUNA_ROOT)/tests/libc
+DESTDIR := $(LUNA_ROOT)/initrd/bin
+
+build:
+	@mkdir -p $(TESTDIR)/bin
+	$(LUNA_ROOT)/tools/sync-libc.sh
+	$(CC) $(TESTDIR)/string.c $(TESTDIR)/Test.c -I$(LUNA_ROOT)/tests -o $(TESTDIR)/bin/test-libc -Wall -Wextra -Wno-stringop-overread -Werror
+
+install:
+	$(LUNA_ROOT)/tools/clean.sh
+	@mkdir -p $(DESTDIR)
+	cp $(TESTDIR)/bin/test-libc $(DESTDIR)/test-libc
+
+test:
+	CFLAGS="-DRUN_TEST_AS_INIT=/bin/test-libc" $(LUNA_ROOT)/tools/run.sh

tests/libc/Test.c

@@ -0,0 +1,11 @@
+#include "Test.h"
+
+DEFINE_TEST(strlen);
+DEFINE_TEST(strnlen);
+
+int main()
+{
+    START_TEST_CASE(string.h);
+    RUN_TEST(strlen);
+    RUN_TEST(strnlen);
+}