apps/CMakeLists.txt

@@ -6,5 +6,5 @@ function(luna_app SOURCE_FILE APP_NAME)
     install(TARGETS ${APP_NAME} DESTINATION ${LUNA_ROOT}/initrd/bin)
 endfunction()
 
-luna_app(init.c init)
+luna_app(app.c app)
 luna_app(hello.c hello)

apps/app.c

@@ -0,0 +1,39 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+
+void bye()
+{
+    printf("byeee!\n");
+}
+
+int main()
+{
+    atexit(bye);
+    printf("Welcome to %s from userspace (pid %d)!\n", "Luna", getpid());
+
+    FILE* f = fopen("/etc/motd", "r");
+    if (!f)
+    {
+        perror("fopen");
+        return 1;
+    }
+
+    char buffer[512];
+    size_t nread = fread(buffer, 1, sizeof(buffer), f);
+    buffer[nread] = 0;
+
+    printf("/etc/motd says: %s", buffer);
+
+    fclose(f);
+
+    time_t now = time(NULL);
+    printf("date: %s", ctime(&now));
+
+    // FIXME: Add libc wrapper.
+    syscall(SYS_exec, "/bin/hello");
+}

apps/init.c

@@ -1,38 +0,0 @@
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/stat.h>
-#include <sys/sysmacros.h>
-#include <unistd.h>
-
-#define xmknod(path, mode, maj, min)                                                                                   \
-    if (mknod(path, mode, makedev(maj, min)) < 0) exit(255);
-
-// Too early for console logs (/dev/console is created here!), so we have to resort to exiting with a weird exit code in
-// case of failure.
-static void populate_devfs()
-{
-    if (mkdir("/dev", 0755) < 0 && errno != EEXIST) exit(255);
-
-    xmknod("/dev/console", 0666, 1, 0);
-    xmknod("/dev/null", 0666, 2, 0);
-}
-
-int main()
-{
-    if (getpid() != 1)
-    {
-        printf("error: init not running as PID 1.\n");
-        return 1;
-    }
-
-    populate_devfs();
-
-    // Before this point, we don't even have an stdout and stderr. Set it up now so that child processes (and us) can
-    // print stuff.
-    stdout = fopen("/dev/console", "w");
-    stderr = fopen("/dev/console", "w");
-
-    fprintf(stderr, "init is running as PID %d\n", getpid());
-}

kernel/src/fs/devices/ConsoleDevice.cpp

@@ -14,6 +14,6 @@ Result<usize> ConsoleDevice::read(u8*, usize, usize) const
 
 Result<usize> ConsoleDevice::write(const u8* buf, usize, usize length)
 {
-    TextConsole::write((const char*)buf, length);
+    TextConsole::print((const char*)buf);
     return length;
 }

kernel/src/main.cpp

@@ -66,9 +66,9 @@ static void init_vfs()
 
 static Result<void> try_init_userspace()
 {
-    auto init = TRY(VFS::resolve_path("/bin/init"));
+    auto app = TRY(VFS::resolve_path("/bin/app"));
 
-    TRY(Scheduler::new_userspace_thread(init));
+    TRY(Scheduler::new_userspace_thread(app));
 
     return {};
 }

kernel/src/video/TextConsole.cpp

@@ -172,12 +172,6 @@ namespace TextConsole
         return {};
     }
 
-    Result<void> write(const char* str, usize len)
-    {
-        while (len--) TRY(putchar(*str++));
-        return {};
-    }
-
     void wprint(const wchar_t* str)
     {
         while (*str) putwchar(*str++);

kernel/src/video/TextConsole.h

@@ -14,7 +14,6 @@ namespace TextConsole
     u32 background();
     void move_to(u32 x, u32 y);
     Result<void> print(const char* str);
-    Result<void> write(const char* str, usize len);
     void wprint(const wchar_t* str);
     Result<void> println(const char* str);
     void wprintln(const wchar_t* str);

libc/CMakeLists.txt

@@ -12,7 +12,6 @@ set(SOURCES
     src/atexit.cpp
     src/ctype.cpp
     src/time.cpp
-    src/init.cpp
     src/sys/stat.cpp
     src/sys/mman.cpp
 )

libc/include/stdio.h

@@ -16,9 +16,7 @@ typedef struct
 
 #define EOF -1
 
-extern FILE* stdout;
 extern FILE* stderr;
-#define stdout stdout
 #define stderr stderr
 
 #ifdef __cplusplus
@@ -31,9 +29,6 @@ extern "C"
     /* Open a file and binds a stream to it. */
     FILE* fopen(const char* path, const char* mode);
 
-    /* Bind a stream to a file descriptor. */
-    FILE* fdopen(int fd, const char* mode);
-
     /* Close a file and frees up its stream. */
     int fclose(FILE* stream);
 
@@ -67,28 +62,13 @@ extern "C"
     /* Return whether the end-of-file indicator was set in stream. */
     int feof(FILE* stream);
 
-    /* Write a character to stream. */
-    int fputc(int c, FILE* stream);
-
-    /* Write a character to stream. */
-    int putc(int c, FILE* stream);
-
-    /* Write a character to standard output. */
-    int putchar(int c);
-
-    /* Write a string to stream. */
-    int fputs(const char* str, FILE* stream);
-
     /* Clear the error and end-of-file indicators in stream. */
     void clearerr(FILE* stream);
 
     void setbuf(FILE*, char*);
 
-    /* Write formatted output to a file. */
-    int fprintf(FILE* stream, const char* format, ...);
-
-    /* Write formatted output to a file. */
-    int vfprintf(FILE* stream, const char* format, va_list ap);
+    int fprintf(FILE*, const char*, ...);
+    int vfprintf(FILE*, const char*, va_list);
 
     /* Write formatted output into a buffer. */
     int sprintf(char* buf, const char* format, ...);
@@ -102,15 +82,15 @@ extern "C"
     /* Write up to max bytes of formatted output into a buffer. */
     int vsnprintf(char*, size_t, const char*, va_list);
 
-    /* Write formatted output to standard output. */
-    int vprintf(const char*, va_list ap);
-
     /* Write formatted output to standard output. */
     int printf(const char*, ...);
 
     /* Write a string followed by a newline to standard output. */
     int puts(const char* s);
 
+    /* Output a message to the console. */
+    int console_write(const char* msg, size_t size);
+
     /* Write an error message to standard error. */
     void perror(const char* s);
 

libc/include/unistd.h

@@ -10,9 +10,6 @@
 #include <stdint.h>
 #include <sys/types.h>
 
-#define STDOUT_FILENO 0
-#define STDERR_FILENO 1
-
 #ifdef __cplusplus
 extern "C"
 {

libc/src/arch/x86_64/crt0.S

@@ -2,7 +2,6 @@
 
 .global _start
 .extern exit
-.extern libc_init
 _start:
 	# Set up end of the stack frame linked list.
 	movq $0, %rbp
@@ -10,8 +9,6 @@ _start:
 	pushq %rbp # rbp=0
 	movq %rsp, %rbp
 
-	call libc_init
-
 	# Run the global constructors.
 	call _init
 

libc/src/init.cpp

@@ -1,11 +0,0 @@
-#include <stdio.h>
-#include <unistd.h>
-
-extern "C"
-{
-    void libc_init()
-    {
-        stdout = fdopen(STDOUT_FILENO, "w");
-        stderr = fdopen(STDERR_FILENO, "w");
-    }
-}

libc/src/stdio.cpp

@@ -9,7 +9,6 @@
 #include <unistd.h>
 
 FILE* stderr = nullptr;
-FILE* stdout = nullptr;
 
 static int fopen_parse_mode(const char* mode)
 {
@@ -30,19 +29,25 @@ static int fopen_parse_mode(const char* mode)
 
 extern "C"
 {
+    int console_write(const char* str, size_t size)
+    {
+        long rc = syscall(SYS_console_write, str, size);
+        __errno_return(rc, int);
+    }
+
     FILE* fopen(const char* path, const char* mode)
     {
         int flags;
 
         if ((flags = fopen_parse_mode(mode)) < 0) return nullptr;
 
-        FILE* f = (FILE*)malloc(sizeof(FILE));
-        if (!f) { return nullptr; }
-
         int fd = open(path, flags, 0666);
-        if (fd < 0)
+        if (fd < 0) return nullptr;
+
+        FILE* f = (FILE*)malloc(sizeof(FILE));
+        if (!f)
         {
-            free(f);
+            close(fd);
             return nullptr;
         }
 
@@ -52,25 +57,6 @@ extern "C"
         return f;
     }
 
-    FILE* fdopen(int fd, const char* mode)
-    {
-        int flags;
-
-        if ((flags = fopen_parse_mode(mode)) < 0) return nullptr;
-
-        // FIXME: We do verify that fd is valid, but not that the mode is compatible.
-        long rc = lseek(fd, 0, SEEK_CUR);
-        if (rc < 0) return nullptr;
-
-        FILE* f = (FILE*)malloc(sizeof(FILE));
-        if (!f) { return nullptr; }
-
-        f->_fd = fd;
-        clearerr(f);
-
-        return f;
-    }
-
     int fclose(FILE* stream)
     {
         if (close(stream->_fd) < 0) return EOF;
@@ -162,30 +148,6 @@ extern "C"
         return stream->_eof;
     }
 
-    int fputc(int c, FILE* stream)
-    {
-        u8 value = (u8)c;
-        ssize_t rc = write(stream->_fd, &value, 1);
-        if (rc <= 0) return EOF;
-        return c;
-    }
-
-    int putc(int c, FILE* stream)
-    {
-        return fputc(c, stream);
-    }
-
-    int putchar(int c)
-    {
-        return fputc(c, stdout);
-    }
-
-    int fputs(const char* str, FILE* stream)
-    {
-        ssize_t rc = write(stream->_fd, str, strlen(str));
-        return (rc < 0) ? -1 : 0;
-    }
-
     void clearerr(FILE* stream)
     {
         stream->_eof = stream->_err = 0;
@@ -225,46 +187,19 @@ extern "C"
         return rc;
     }
 
-    int vfprintf(FILE* stream, const char* format, va_list ap)
-    {
-        usize rc = cstyle_format(
-                       format,
-                       [](char c, void* f) -> Result<void> {
-                           int rc = fputc(c, (FILE*)f);
-                           if (rc == EOF) return err(errno);
-                           return {};
-                       },
-                       stream, ap)
-                       .value_or(-1);
-
-        if (rc == (usize)-1) return -1;
-
-        return (int)rc;
-    }
-
-    int fprintf(FILE* stream, const char* format, ...)
-    {
-        va_list ap;
-        va_start(ap, format);
-
-        int rc = vfprintf(stream, format, ap);
-
-        va_end(ap);
-
-        return rc;
-    }
-
-    int vprintf(const char* format, va_list ap)
-    {
-        return vfprintf(stdout, format, ap);
-    }
-
     int printf(const char* format, ...)
     {
         va_list ap;
         va_start(ap, format);
 
-        int rc = vfprintf(stdout, format, ap);
+        int rc = (int)cstyle_format(
+                     format,
+                     [](char c, void*) -> Result<void> {
+                         console_write(&c, 1);
+                         return {};
+                     },
+                     nullptr, ap)
+                     .value();
 
         va_end(ap);
 
@@ -273,22 +208,30 @@ extern "C"
 
     int puts(const char* s)
     {
-        if (fputs(s, stdout) < 0) return -1;
-        if (putchar('\n') == EOF) return -1;
+        if (console_write(s, strlen(s)) < 0) return -1;
+        if (console_write("\n", 1) < 0) return -1;
 
         return 0;
     }
 
     void perror(const char* s)
     {
+        // FIXME: Output to stderr when available.
         int err = errno;
-        if (s && *s) fprintf(stderr, "%s: ", s);
-        fprintf(stderr, "%s\n", strerror(err));
+        if (s && *s) printf("%s: ", s);
+        printf("%s\n", strerror(err));
     }
 }
 
 void debug_log_impl(const char* format, va_list ap)
 {
-    vfprintf(stderr, format, ap);
-    fputc('\n', stderr);
+    cstyle_format(
+        format,
+        [](char c, void*) -> Result<void> {
+            console_write(&c, 1);
+            return {};
+        },
+        nullptr, ap)
+        .value();
+    console_write("\n", 1);
 }