modified some syscall code in rlibc, fs stuff

compile_commands.json

@@ -1,4 +1,21 @@
 [
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/initrd.c.o",
+      "kernel/initrd.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/initrd.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/initrd.c.o"
+  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -26,12 +43,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/kmain.c.o",
+      "obj/kernel/gdt.c.o",
-      "kernel/kmain.c"
+      "kernel/gdt.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/kmain.c",
+    "file": "/home/slinky/source/RockOS/kernel/gdt.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/kmain.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.c.o"
   },
   {
     "arguments": [
@@ -50,40 +67,6 @@
     "file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic.c",
     "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic.c.o"
   },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/vga/vga.c.o",
-      "kernel/drivers/vga/vga.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/vga/vga.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/vga/vga.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/ide/ide.c.o",
-      "kernel/drivers/ide/ide.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/ide/ide.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/ide/ide.c.o"
-  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -128,12 +111,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/gdt.c.o",
+      "obj/kernel/drivers/ide/ide.c.o",
-      "kernel/gdt.c"
+      "kernel/drivers/ide/ide.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/gdt.c",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/ide/ide.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/ide/ide.c.o"
   },
   {
     "arguments": [
@@ -145,12 +128,29 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/memory/mm.c.o",
+      "obj/kernel/drivers/vga/vga.c.o",
-      "kernel/memory/mm.c"
+      "kernel/drivers/vga/vga.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/memory/mm.c",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/vga/vga.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/vga/vga.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/scheduler.c.o",
+      "kernel/scheduler.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/scheduler.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/scheduler.c.o"
   },
   {
     "arguments": [
@@ -196,46 +196,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/lib/stream.c.o",
+      "obj/kernel/kmain.c.o",
-      "kernel/lib/stream.c"
+      "kernel/kmain.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/stream.c",
+    "file": "/home/slinky/source/RockOS/kernel/kmain.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/stream.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/kmain.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/lib/memory.c.o",
-      "kernel/lib/memory.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/memory.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/memory.c.o"
-  },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/lib/print.c.o",
-      "kernel/lib/print.c"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/lib/print.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/lib/print.c.o"
   },
   {
     "arguments": [
@@ -264,12 +230,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/scheduler.c.o",
+      "obj/kernel/lib/stream.c.o",
-      "kernel/scheduler.c"
+      "kernel/lib/stream.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/scheduler.c",
+    "file": "/home/slinky/source/RockOS/kernel/lib/stream.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/scheduler.c.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/stream.c.o"
   },
   {
     "arguments": [
@@ -281,12 +247,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/syscall.S.o",
+      "obj/kernel/lib/print.c.o",
-      "kernel/syscall.S"
+      "kernel/lib/print.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/syscall.S",
+    "file": "/home/slinky/source/RockOS/kernel/lib/print.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/syscall.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/print.c.o"
   },
   {
     "arguments": [
@@ -298,12 +264,46 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/common.S.o",
+      "obj/kernel/lib/memory.c.o",
-      "kernel/common.S"
+      "kernel/lib/memory.c"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/common.S",
+    "file": "/home/slinky/source/RockOS/kernel/lib/memory.c",
-    "output": "/home/slinky/source/RockOS/obj/kernel/common.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/lib/memory.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/vfs.c.o",
+      "kernel/vfs.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/vfs.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/vfs.c.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/memory/mm.c.o",
+      "kernel/memory/mm.c"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/memory/mm.c",
+    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.c.o"
   },
   {
     "arguments": [
@@ -322,23 +322,6 @@
     "file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic.S",
     "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic.S.o"
   },
-  {
-    "arguments": [
-      "/home/slinky/opt/cross/bin/i686-elf-gcc",
-      "-c",
-      "-ffreestanding",
-      "-O2",
-      "-Wall",
-      "-Wextra",
-      "-Ikernel",
-      "-o",
-      "obj/kernel/drivers/pit/pit.S.o",
-      "kernel/drivers/pit/pit.S"
-    ],
-    "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/drivers/pit/pit.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pit/pit.S.o"
-  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -366,12 +349,46 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/memory/mm_stubs.S.o",
+      "obj/kernel/drivers/pit/pit.S.o",
-      "kernel/memory/mm_stubs.S"
+      "kernel/drivers/pit/pit.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/memory/mm_stubs.S",
+    "file": "/home/slinky/source/RockOS/kernel/drivers/pit/pit.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm_stubs.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/drivers/pit/pit.S.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/syscall.S.o",
+      "kernel/syscall.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/syscall.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/syscall.S.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/interrupts.S.o",
+      "kernel/interrupts.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/interrupts.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/interrupts.S.o"
   },
   {
     "arguments": [
@@ -390,6 +407,23 @@
     "file": "/home/slinky/source/RockOS/kernel/boot/boot.S",
     "output": "/home/slinky/source/RockOS/obj/kernel/boot/boot.S.o"
   },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-c",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-Ikernel",
+      "-o",
+      "obj/kernel/common.S.o",
+      "kernel/common.S"
+    ],
+    "directory": "/home/slinky/source/RockOS",
+    "file": "/home/slinky/source/RockOS/kernel/common.S",
+    "output": "/home/slinky/source/RockOS/obj/kernel/common.S.o"
+  },
   {
     "arguments": [
       "/home/slinky/opt/cross/bin/i686-elf-gcc",
@@ -417,12 +451,12 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/gdt.S.o",
+      "obj/kernel/memory/mm_stubs.S.o",
-      "kernel/gdt.S"
+      "kernel/memory/mm_stubs.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/gdt.S",
+    "file": "/home/slinky/source/RockOS/kernel/memory/mm_stubs.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/memory/mm_stubs.S.o"
   },
   {
     "arguments": [
@@ -434,11 +468,11 @@
       "-Wextra",
       "-Ikernel",
       "-o",
-      "obj/kernel/interrupts.S.o",
+      "obj/kernel/gdt.S.o",
-      "kernel/interrupts.S"
+      "kernel/gdt.S"
     ],
     "directory": "/home/slinky/source/RockOS",
-    "file": "/home/slinky/source/RockOS/kernel/interrupts.S",
+    "file": "/home/slinky/source/RockOS/kernel/gdt.S",
-    "output": "/home/slinky/source/RockOS/obj/kernel/interrupts.S.o"
+    "output": "/home/slinky/source/RockOS/obj/kernel/gdt.S.o"
   }
 ]

grub.cfg

@@ -1,3 +1,4 @@
 menuentry "RockOS" {
-	multiboot /boot/rockos
+	multiboot /boot/rockos/
+	module /boot/initrd.img
 }

kernel/initrd.c

@@ -0,0 +1,34 @@
+#include "initrd.h"
+
+#include <stdint.h>
+
+#include <lib/print.h>
+#include <lib/memory.h>
+
+void parse_cpio(void *initrd_start) {
+    cpio_header_t *head = (cpio_header_t *)initrd_start;
+
+    while (strncmp(head->c_magic, "070701", 6) == 0) {
+        // If we hit the trailer, we are done
+        char *filename = (char *)(head + 1); 
+        if (strncmp(filename, "TRAILER!!!", 10) == 0) {
+            break; 
+        }
+
+        uint32_t filesize = parse_hex(head->c_filesize);
+        uint32_t namesize = parse_hex(head->c_namesize);
+        
+        kprintf("found file of size %d\n", filesize);
+
+        // Calculate where the data begins (accounting for 4-byte padding)
+        uint32_t header_plus_name = 110 + namesize;
+        header_plus_name = (header_plus_name + 3) & ~3; // Align to 4 bytes
+        
+        char *file_data = (char *)head + header_plus_name;
+
+        uint32_t total_record_size = header_plus_name + filesize;
+        total_record_size = (total_record_size + 3) & ~3; // Align to 4 bytes
+        
+        head = (cpio_header_t *)((char *)head + total_record_size);
+    }
+}

kernel/initrd.h

@@ -0,0 +1,36 @@
+#ifndef KINITRD_H
+#define KINITRD_H
+
+#include <stdint.h>
+
+typedef struct {
+    char c_magic[6];
+    char c_ino[8];
+    char c_mode[8];
+    char c_uid[8];
+    char c_gid[8];
+    char c_nlink[8];
+    char c_mtime[8];
+    char c_filesize[8];
+    char c_devmajor[8];
+    char c_devminor[8];
+    char c_rdevmajor[8];
+    char c_rdevminor[8];
+    char c_namesize[8];
+    char c_check[8];
+} cpio_header_t;
+
+static inline uint32_t parse_hex(const char *s) {
+    uint32_t val = 0;
+    for (int i = 0; i < 8; i++) {
+        val <<= 4;
+        if (s[i] >= '0' && s[i] <= '9')      val += (s[i] - '0');
+        else if (s[i] >= 'A' && s[i] <= 'F') val += (s[i] - 'A' + 10);
+        else if (s[i] >= 'a' && s[i] <= 'f') val += (s[i] - 'a' + 10);
+    }
+    return val;
+}
+
+void parse_cpio(void *initrd_start);
+
+#endif

kernel/kmain.c

@@ -3,6 +3,7 @@
 #include "gdt.h"
 #include "scheduler.h"
 #include "common.h"
+#include "initrd.h"
 
 #include <lib/print.h>
 #include <lib/stream.h>
@@ -23,15 +24,32 @@
 extern char __kernel_start;
 extern char __kernel_end;
 
-void first_task() {
+void parse_multiboot_modules(uint32_t mbi_vaddr) {
-  kprintf("task started\n");
+  // find where grub put the boot module containing initrd
-  int i = 5;
+  multiboot_info* mbi = (multiboot_info*)mbi_vaddr;
-  while (i--) {
+
-    sleep(1000);
+  uint32_t mod_count = mbi->mods_count;
-    kprintf("task awake [%d]\n", i);
+  multiboot_module_t* mod = (multiboot_module_t*)((uint32_t)mbi->mods_addr + 0xC0000000);
+
+  kprintf("found %d mods starting @ [v]0x%x\n", mod_count, (uint32_t)mod);
+
+  for (uint32_t i = 0; i < mod_count; i++) {
+    uint32_t start = mod[i].mod_start;
+    uint32_t end = mod[i].mod_end;
+    uint32_t cmdline = mod[i].cmdline;
+
+    multiboot_module_info_table[i].mod_start = start + 0xC0000000;
+    multiboot_module_info_table[i].mod_end = end + 0xC0000000;
+    multiboot_module_info_table[i].cmdline = cmdline + 0xC0000000;
   }
-  kprintf("exiting\n");
+}
-  exit();
+
+void load_initrd() {
+  multiboot_module_t* initrd_module = &multiboot_module_info_table[0];
+  kprintf("initrd found @ [v] 0x%x\n", initrd_module->mod_start);
+  kprintf("reading initrd\n");
+
+  parse_cpio((void*)initrd_module->mod_start);
 }
 
 void kmain(uint32_t magic, multiboot_info* mbi)  {
@@ -53,16 +71,13 @@ void kmain(uint32_t magic, multiboot_info* mbi)  {
   
   init_page_tables();
 
+  parse_multiboot_modules((uint32_t)mbi);
+
+  load_initrd();
+
   kprintf("basic initializations complete\n");
 
   disable_interrupts(); // just paranoid... do it again
   init_scheduler();
   enable_interrupts();
-
-  create_task((uint32_t)first_task, fetch_cr3());
-
-  while(1) {
-    sleep(5000);
-    kprintf("kernel awake\n");
-  }
 }

kernel/lib/memory.c

@@ -38,6 +38,26 @@ int strlen(const char* str) {
     return len;
 }
 
+int strncmp(const char *s1, const char *s2, size_t n) {
+    // If n is 0, we don't compare anything and strings are "equal"
+    while (n > 0) {
+        // If characters don't match, or we hit the null-terminator of s1
+        if (*s1 != *s2) {
+            return *(unsigned char *)s1 - *(unsigned char *)s2;
+        }
+        
+        // If we reached the end of the strings simultaneously
+        if (*s1 == '\0') {
+            break;
+        }
+        
+        s1++;
+        s2++;
+        n--;
+    }
+    return 0;
+}
+
 static void* kernel_heap_start = (void*)KHEAP_START;
 static void* kernel_heap_end = (void*)KHEAP_START;
 alloc_header_t* blk_list = NULL;

kernel/lib/memory.h

@@ -8,6 +8,7 @@ void memcpy(const void* src, void* dst, size_t sz);
 void memset(const uint8_t* dst, uint8_t val, size_t sz);
 
 int strcmp(const char *s1, const char *s2);
+int strncmp(const char *s1, const char *s2, size_t n);
 int strlen(const char* str);
 
 void kgrow(size_t pages);

kernel/memory/mm.c

@@ -109,7 +109,7 @@ void* p_alloc_frame() {
     return 0;
 }
 
-static void p_free_frame(void* addr) {
+void p_free_frame(void* addr) {
     mark_free((uint32_t)addr);
 }
 

kernel/multiboot.c

@@ -0,0 +1,3 @@
+#include "multiboot.h"
+
+multiboot_module_t multiboot_module_info_table[32];

kernel/multiboot.h

@@ -31,6 +31,8 @@ typedef struct {
     uint32_t mod_end;   // Physical end address of user.elf
     uint32_t cmdline;   // Pointer to a string (e.g., "/boot/user.elf")
     uint32_t pad;
-} __attribute__((packed)) multiboot_module_entry;
+} __attribute__((packed)) multiboot_module_t;
+
+extern multiboot_module_t multiboot_module_info_table[32];
 
 #endif

kernel/process.h

@@ -17,6 +17,7 @@ typedef struct {
     process_state_t state;
     uint32_t sleep;
     void* next;
+    uint32_t heap_end;
 } __attribute__((packed)) process_t;
 
 #endif 

kernel/scheduler.c

@@ -137,6 +137,13 @@ int create_task(uint32_t entry_point, uint32_t cr3) {
     return 1;
 }
 
+process_t* current_task() {
+    lock_scheduler();
+    process_t* rtn = &process_table[current_process];
+    unlock_scheduler();
+    return rtn;
+}
+
 void sleep(uint32_t ms) {
     if (ms == 0) return;
     lock_scheduler();

kernel/scheduler.h

@@ -1,11 +1,13 @@
 #ifndef KSCHEDULER_H
 #define KSCHEDULER_H
 
+#include "process.h"
 #include <stdint.h>
 
 void init_scheduler();
 
 int create_task(uint32_t entry_point, uint32_t cr3);
+process_t* current_task();
 
 void sleep(uint32_t ms);
 void yield();

kernel/syscall.c

@@ -1,7 +1,12 @@
 #include <stdint.h>
+#include <stddef.h>
 
+#include "memory/mm.h"
+#include "process.h"
 #include "scheduler.h"
 
+#include <drivers/vga/vga.h>
+
 typedef struct registers {
     uint32_t gs, fs, es, ds;                           // Pushed manually
     uint32_t edi, esi, ebp, esp, ebx, edx, ecx, eax;   // Pushed by pusha
@@ -9,35 +14,81 @@ typedef struct registers {
     uint32_t eip, cs, eflags, useresp, ss;             // Pushed automatically by CPU
 } registers_t;
 
-int32_t sys_exit();
-int32_t sys_read();
-int32_t sys_write();
-int32_t sys_open();
-int32_t sys_close();
-int32_t sys_brk();
 
-int32_t syscall(registers_t* regs) {
+static int32_t sys_exit(int status) {
-    switch(regs->eax) {
-        case 1: return sys_exit();
-        case 3: return sys_read();
-        case 4: return sys_write();
-        case 5: return sys_open();
-        case 6: return sys_close();
-        case 12: return sys_brk();
-        default:
-            return -1;
-    }
-}
-
-int32_t sys_exit() {
     exit();
     return 0;
 }
 
-int32_t sys_read() {
+static int32_t sys_write(int fd, const void* buf, size_t count) {
-    return 0;
+    if (fd == 1 || fd == 2) { // stdout or stderr
+        const char* cbuf = (const char*)buf;
+        for (size_t i = 0; i < count; i++) {
+            vga_putchar(cbuf[i]); 
+        }
+        return count;
+    }
+    return -1;
 }
 
-int32_t sys_write() {
+static int32_t sys_read(int fd, void* buf, size_t count) {
-    return 0;
+    if (fd == 0) { // stdin
+        char* cbuf = (char*)buf;
+        size_t bytes_read = 0;
+        while (bytes_read < count) {
+            char c = 'r';
+            cbuf[bytes_read++] = c;
+            if (c == '\n') break;
+        }
+        return bytes_read;
+    }
+    return -1; 
+}
+
+static int32_t sys_open(const char* filename, int flags) {
+    return -1; 
+}
+
+static int32_t sys_close(int fd) {
+    return -1;
+}
+
+static int32_t sys_brk(uint32_t new_break) {
+    process_t* current = current_task();
+
+    if (new_break == 0) {
+        return current->heap_end;
+    }
+
+    if (new_break < current->heap_end) {
+        current->heap_end = new_break;
+        return current->heap_end;
+    }
+
+    uint32_t page_start = (current->heap_end + 4095) & ~4095;
+    uint32_t page_end   = (new_break + 4095) & ~4095;
+
+    for (uint32_t addr = page_start; addr < page_end; addr += 4096) {
+        // 1. Allocate a physical frame using your PMM (Physical Memory Manager)
+        void* phys = p_alloc_frame();
+        
+        // 2. Map it into the current page directory using your VMM (Virtual Memory Manager)
+        map_page(addr, (uint32_t)phys, PAGE_PRESENT | PAGE_WRITABLE | PAGE_USER);
+    }
+
+    current->heap_end = new_break;
+    return current->heap_end;
+}
+
+int32_t syscall(registers_t* regs) {
+    switch(regs->eax) {
+        case 1: return sys_exit(regs->ebx);
+        case 3: return sys_read(regs->ebx, (void*)regs->ecx, regs->edx);
+        case 4: return sys_write(regs->ebx, (const void*)regs->ecx, regs->edx);
+        case 5: return sys_open((const char*)regs->ebx, regs->ecx);
+        case 6: return sys_close(regs->ebx);
+        case 12: return sys_brk(regs->ebx);
+        default:
+            return -1;
+    }
 }

kernel/vfs.c

@@ -0,0 +1,12 @@
+#include "vfs.h"
+#include "lib/memory.h"
+#include <string.h>
+
+vfs_node_t* root = NULL;
+
+void vfs_create_root() {
+    root = kalloc(sizeof(vfs_node_t));
+    memset((uint8_t*)root->name, 0, 128);
+    memcpy("root", root->name, 4);
+    root->flags |= VFS_DIRECTORY;
+}

kernel/vfs.h

@@ -0,0 +1,30 @@
+#ifndef KVFS_H
+#define KVFS_H
+
+#include <stdint.h>
+
+#define VFS_FILE      0x01
+#define VFS_DIRECTORY 0x02
+
+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 struct vfs_node* (*finddir_type_t)(struct vfs_node* node, const char* name);
+
+typedef struct vfs_node {
+    char name[128];
+    uint32_t flags;       // File, directory, device, etc.
+    uint32_t size;        // Size of file in bytes
+    uint32_t inode;       // Unique identifier managed by the specific filesystem
+    
+    read_type_t read;
+    write_type_t write;
+    finddir_type_t finddir; 
+
+    struct vfs_node* mount;
+} vfs_node_t;
+
+void vfs_create_root();
+
+#endif