Kernel, libc: Add ioctl()

Right now, only the framebuffer supports this system call, to query its dimensions.

kernel/include/fs/FileDescriptor.h

@@ -34,6 +34,8 @@ struct Descriptor
 
     uintptr_t mmap(uintptr_t addr, size_t size, int prot, off_t offset);
 
+    long ioctl(int cmd, uintptr_t arg);
+
     void open(VFS::Node* node, bool can_read, bool can_write, bool able_to_block, bool close_on_exec);
 
     int seek(long offset);

kernel/include/fs/VFS.h

@@ -24,6 +24,7 @@ namespace VFS
     typedef int (*node_block)(Node*);
     typedef Node* (*node_readdir)(Node*, long);
     typedef uintptr_t (*node_mmap)(Node*, uintptr_t, size_t, int, off_t);
+    typedef long (*node_ioctl)(Node*, int, uintptr_t);
 
     struct Node
     {
@@ -47,6 +48,7 @@ namespace VFS
         node_write write_func;
         node_block block_func;
         node_mmap mmap_func;
+        node_ioctl ioctl_func;
         Node* link;
     };
 

kernel/include/fs/devices/Framebuffer.h

@@ -8,4 +8,6 @@ namespace FramebufferDevice
     ssize_t write(VFS::Node* node, size_t offset, size_t size, const char* buffer);
 
     uintptr_t mmap(VFS::Node* node, uintptr_t addr, size_t size, int prot, off_t offset);
+
+    long ioctl(VFS::Node* node, int cmd, uintptr_t arg);
 }

kernel/include/sys/Syscall.h

@@ -30,6 +30,7 @@
 #define SYS_setuid 24
 #define SYS_setgid 25
 #define SYS_umask 26
+#define SYS_ioctl 27
 
 struct stat;
 struct pstat;
@@ -68,3 +69,4 @@ void sys_dup2(Context* context, int fd, int fd2);
 void sys_setuid(Context* context, int new_uid, int new_euid);
 void sys_setgid(Context* context, int new_gid, int new_egid);
 void sys_umask(Context* context, mode_t cmask);
+void sys_ioctl(Context* context, int fd, int request, uintptr_t arg);

kernel/src/fs/FileDescriptor.cpp

@@ -45,6 +45,12 @@ uintptr_t Descriptor::mmap(uintptr_t addr, size_t size, int prot, off_t offset)
     return m_node->mmap_func(m_node, addr, size, prot, offset);
 }
 
+long Descriptor::ioctl(int cmd, uintptr_t arg)
+{
+    if(!m_node->ioctl_func) return MAP_FAIL(ENOTSUP);
+    return m_node->ioctl_func(m_node, cmd, arg);
+}
+
 int Descriptor::seek(long offset)
 {
     if (m_node->type == VFS_FILE && (uint64_t)offset > m_node->length)

kernel/src/fs/devices/Framebuffer.cpp

@@ -20,6 +20,7 @@ VFS::Node* FramebufferDevice::create_new(const char* devname)
     VFS::Node* dev = new VFS::Node;
     dev->write_func = FramebufferDevice::write;
     dev->mmap_func = FramebufferDevice::mmap;
+    dev->ioctl_func = FramebufferDevice::ioctl;
     dev->inode = 0;
     dev->length = 0;
     dev->type = VFS_DEVICE;
@@ -57,3 +58,17 @@ ssize_t FramebufferDevice::write(VFS::Node* node, size_t offset, size_t size, co
     memcpy(fb + offset, buffer, size);
     return (ssize_t)size;
 }
+
+#define FB_GET_WIDTH 0
+#define FB_GET_HEIGHT 1
+
+long FramebufferDevice::ioctl(VFS::Node* node, int cmd, uintptr_t)
+{
+    if (!node) return -1;
+    switch(cmd)
+    {
+        case FB_GET_WIDTH: return (long)bootboot.fb_width;
+        case FB_GET_HEIGHT: return (long)bootboot.fb_height;
+        default: return -EINVAL;
+    }
+}

kernel/src/sys/Syscall.cpp

@@ -40,6 +40,7 @@ void Syscall::entry(Context* context)
     case SYS_setuid: sys_setuid(context, (int)context->rdi, (int)context->rsi); break;
     case SYS_setgid: sys_setgid(context, (int)context->rdi, (int)context->rsi); break;
     case SYS_umask: sys_umask(context, (mode_t)context->rdi); break;
+    case SYS_ioctl: sys_ioctl(context, (int)context->rdi, (int)context->rsi, (uintptr_t)context->rdx); break;
     default: context->rax = -ENOSYS; break;
     }
     VMM::exit_syscall_context();

kernel/src/sys/stdio.cpp

@@ -358,12 +358,7 @@ void sys_dup2(Context* context, int fd, int fd2)
         context->rax = -err;
         return;
     }
-    if (!file1->is_open())
-    {
-        context->rax = -EBADF;
-        return;
-    }
-    Descriptor* file2 = Scheduler::current_task()->descriptor_from_fd(fd2, err);
+    Descriptor* file2 = Scheduler::current_task()->descriptor_from_fd(fd2, err); // FIXME: This will return EBADF if fd2 is not open, but we want to replace it with fd1 if it is not open.
     if (!file2)
     {
         context->rax = -err;
@@ -381,3 +376,16 @@ void sys_umask(Context* context, mode_t cmask)
     context->rax = current_task->umask;
     current_task->umask = cmask;
 }
+
+void sys_ioctl(Context* context, int fd, int cmd, uintptr_t arg)
+{
+    int err;
+    Descriptor* file = Scheduler::current_task()->descriptor_from_fd(fd, err);
+    if (!file)
+    {
+        context->rax = -err;
+        return;
+    }
+    kinfoln("ioctl(): fd %d, cmd %d, arg %lu", fd, cmd, arg);
+    context->rax = file->ioctl(cmd, arg);
+}

libs/libc/include/sys/ioctl.h

@@ -0,0 +1,23 @@
+#ifndef _SYS_IOCTL_H
+#define _SYS_IOCTL_H
+
+#include <sys/types.h>
+
+/* Get the width of a framebuffer device. */
+#define FB_GET_WIDTH 0
+/* Get the height of a framebuffer device. */
+#define FB_GET_HEIGHT 1
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Perform an arbitrary operation on an open file descriptor. Many operations are device-specific. */
+    int ioctl(int fd, int cmd, ...);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/include/sys/syscall.h

@@ -28,5 +28,6 @@
 #define SYS_setuid 24
 #define SYS_setgid 25
 #define SYS_umask 26
+#define SYS_ioctl 27
 
 #endif

libs/libc/src/sys/ioctl.cpp

@@ -0,0 +1,17 @@
+#include <luna/syscall.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+extern "C"
+{
+    int ioctl(int fd, int cmd, ...)
+    {
+        va_list ap;
+        va_start(ap, cmd);
+        long result = __lc_fast_syscall3(SYS_ioctl, fd, cmd, va_arg(ap, uintptr_t));
+        va_end(ap);
+        return (int)result;
+    }
+}

libs/libc/src/syscall.cpp

@@ -41,6 +41,7 @@ extern "C" long syscall(long number, ...)
     case SYS_seek:
     case SYS_write:
     case SYS_read:
+    case SYS_ioctl:
     case SYS_mprotect:
     case SYS_waitpid: {
         arg arg0 = va_arg(ap, arg);