modified some syscall code in rlibc, fs stuff

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) {
-    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() {
+static int32_t sys_exit(int status) {
     exit();
     return 0;
 }
 
-int32_t sys_read() {
-    return 0;
+static int32_t sys_write(int fd, const void* buf, size_t count) {
+    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() {
-    return 0;
+static int32_t sys_read(int fd, void* buf, size_t count) {
+    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;
+    }
 }