added some useless shell commands

kernel/drivers/vga/vga.c

@@ -79,13 +79,15 @@ void vga_putchar(char c) {
 	}
 }
 
-uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf) {
+uint32_t vga_seek(vfs_node_t* node, uint32_t offset, int whence) {
 	terminal_row = offset / VGA_WIDTH;
 	terminal_column = offset % VGA_WIDTH;
+	return 0;
+}
 
+uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf) {
 	for (uint32_t i = 0; i < size; i++) {
 		vga_putchar((char)buf[i]);
 	}
-
 	return size;
 }

kernel/drivers/vga/vga.h

@@ -7,5 +7,6 @@ void vga_init();
 void vga_putchar(char c);
 
 uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf);
+uint32_t vga_seek(vfs_node_t* node, uint32_t offset, int whence);
 
 #endif

kernel/kbd.c

@@ -79,6 +79,8 @@ void kbd_wait() {
     }
 }
 
-char kbd_read() {
-    return kbd_pop();
+uint32_t kbd_read(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    if (!kbd_ready()) return -1;
+    buffer[0] = kbd_pop();
+    return 1;
 }

kernel/kbd.h

@@ -1,6 +1,9 @@
 #pragma once 
 
-char kbd_read();
+#include <stdint.h>
+#include <vfs.h>
+
+uint32_t kbd_read(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer);
 void kbd_push(char c);
 int kbd_ready();
 void kbd_wait();

kernel/kmain.c

@@ -6,6 +6,7 @@
 #include "vfs.h"
 #include "elf.h"
 #include "gdt.h"
+#include "kbd.h"
 
 #include <lib/print.h>
 #include <lib/stream.h>
@@ -135,6 +136,10 @@ void kmain(uint32_t magic, multiboot_info* mbi)  {
 
   vfs_node_t* vga_dev = devfs->create(devfs, "tvga");
   vga_dev->write = vga_write;
+  vga_dev->seek = vga_seek;
+
+  vfs_node_t* kbd_dev = devfs->create(devfs, "kbd");
+  kbd_dev->read = kbd_read;
 
   vfs_node_t* dev = vfs_find("/dev");
   if (dev) {

kernel/syscall.c

@@ -196,6 +196,15 @@ static int32_t sys_dup2(int src, int dst) {
     return dst;
 }
 
+static int32_t sys_lseek(int fd, size_t offset, int whence) {
+    if (fd < 0) return 0;
+    process_t* task = current_task();
+    file_t* file = task->fd_table[fd];
+    if (!file) return 0;
+    file->node->seek(file->node, offset, whence);
+    return 1;
+}
+
 void syscall(registers_t* regs) {
     int32_t ret;
     switch(regs->eax) {
@@ -209,6 +218,7 @@ void syscall(registers_t* regs) {
         case 21: ret = sys_fork(regs); break;
         case 22: ret = sys_exec(regs, (const char*)regs->ebx); break;
         case 23: ret = sys_dup2(regs->ebx, regs->ecx); break;
+        case 24: ret = sys_lseek(regs->ebx, regs->ecx, regs->edx); break;
         default: ret = -1;
     }
     regs->eax = ret;

kernel/vfs.h

@@ -14,6 +14,7 @@ struct vfs_node;
 
 typedef uint32_t (*read_type_t)(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer);
 typedef uint32_t (*write_type_t)(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer);
+typedef uint32_t (*seek_type_t)(struct vfs_node* node, uint32_t offset, int whence);
 typedef struct vfs_node* (*finddir_type_t)(struct vfs_node* node, const char* name);
 typedef struct vfs_node* (*mkdir_type_t)(struct vfs_node* node, const char* name);
 typedef struct vfs_node* (*create_type_t)(struct vfs_node* node, const char* name);
@@ -31,6 +32,7 @@ typedef struct vfs_node {
     finddir_type_t find; 
     mkdir_type_t mkdir;
     create_type_t create;
+    seek_type_t seek;
 
     struct vfs_node* mnt;
     void* data;