starting to work on pty drivers, fork(), and scheduler redesign

programs/vga_text_term/compile_commands.json

@@ -0,0 +1,36 @@
+[
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-I../../rocklibc/include",
+      "-c",
+      "-o",
+      "crt0.o",
+      "crt0.S"
+    ],
+    "directory": "/home/slinky/source/RockOS/programs/vga_text_term",
+    "file": "/home/slinky/source/RockOS/programs/vga_text_term/crt0.S",
+    "output": "/home/slinky/source/RockOS/programs/vga_text_term/crt0.o"
+  },
+  {
+    "arguments": [
+      "/home/slinky/opt/cross/bin/i686-elf-gcc",
+      "-ffreestanding",
+      "-O2",
+      "-Wall",
+      "-Wextra",
+      "-I../../rocklibc/include",
+      "-c",
+      "-o",
+      "main.o",
+      "main.c"
+    ],
+    "directory": "/home/slinky/source/RockOS/programs/vga_text_term",
+    "file": "/home/slinky/source/RockOS/programs/vga_text_term/main.c",
+    "output": "/home/slinky/source/RockOS/programs/vga_text_term/main.o"
+  }
+]

programs/vga_text_term/crt0.S

@@ -0,0 +1,21 @@
+.global _start
+.extern exit
+.section .text
+_start: 
+    xor %ebp, %ebp
+
+    mov (%esp), %eax
+    lea 4(%esp), %ebx
+    lea 8(%esp,%eax,4), %ecx
+
+    and $-16, %esp
+
+    push %ecx
+    push %ebx
+    push %eax
+
+    call main
+
+    push %eax
+    call exit
+

programs/vga_text_term/linker.ld

@@ -0,0 +1,31 @@
+ENTRY(_start)
+
+SECTIONS
+{
+    . = 0x40000000;
+
+    .text ALIGN(4K) :
+    {
+        /* Force the crt0.o entry code to be placed FIRST in memory */
+        KEEP(*crt0.o(.text))
+        *(.text .text.*)
+    }
+
+    .rodata ALIGN(4K) :
+    {
+        *(.rodata .rodata.*)
+    }
+
+    .data ALIGN(4K) :
+    {
+        *(.data .data.*)
+    }
+
+    .bss ALIGN(4K) :
+    {
+        _bss_start = .;
+        *(.bss .bss.*)
+        *(COMMON)
+        _bss_end = .;
+    }
+}

programs/vga_text_term/main.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+    return 0;
+}

programs/vga_text_term/makefile

@@ -0,0 +1,23 @@
+CC = i686-elf-gcc
+LD = i686-elf-ld
+
+CFLAGS = -ffreestanding -O2 -Wall -Wextra -I../../rocklibc/include
+LDFLAGS = -m elf_i386 -nostdlib
+
+TARGET = vga_text_term.elf
+
+all: $(TARGET)
+
+crt0.o: crt0.S
+	$(CC) $(CFLAGS) -c crt0.S -o crt0.o
+
+main.o: main.c
+	$(CC) $(CFLAGS) -c main.c -o main.o
+
+$(TARGET): crt0.o main.o ../lib/rlibc.a
+	$(LD) $(LDFLAGS) -T linker.ld crt0.o main.o ../lib/rlibc.a -o $(TARGET)
+
+clean:
+	rm -f *.o $(TARGET)
+
+.PHONY: all clean test

programs/vga_text_term/syscall.c

@@ -0,0 +1,104 @@
+#include <stdint.h>
+#include <stddef.h>
+
+#include "memory/mm.h"
+#include "process.h"
+#include "scheduler.h"
+#include "kbd.h"
+
+#include <drivers/vga/vga.h>
+
+#include <lib/print.h>
+
+
+static int32_t sys_exit(int status) {
+    process_t* task = current_task();
+    task->state = STATE_DEAD;
+    kprintf("Process %d exited with status %d\n", task->pid, status);
+    exit();
+    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;
+}
+
+static int32_t sys_read(int fd, void* buf, size_t count) {
+    if (fd == 0) {
+        char* cbuf = (char*)buf;
+        size_t bytes_read = 0;
+
+        while (bytes_read < count) {
+            kbd_wait();
+            
+            if (kbd_ready()) {
+                char c = kbd_read();
+                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;
+}
+
+typedef struct registers {
+    uint32_t gs, fs, es, ds;                           // Pushed manually
+    uint32_t edi, esi, ebp, esp, ebx, edx, ecx, eax;   // Pushed by pusha
+    uint32_t int_no, err_code;                         // Pushed manually
+    uint32_t eip, cs, eflags, useresp, ss;             // Pushed automatically by CPU
+} registers_t;
+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;
+    }
+}