syscalls: start implementing some basic syscalls

Makefile

@@ -3,7 +3,7 @@ OBJS = bin/boot.o bin/kernel.o bin/idt.o bin/isr.o bin/screen.o \
        bin/utils.o bin/string.o bin/stdio.o bin/disk.o bin/pic.o bin/pit.o \
        bin/keyboard.o bin/paging.o bin/page_alloc.o bin/page_tables.o \
        bin/fat.o bin/task.o bin/switch.o bin/sys_exit.o bin/gdt.o bin/isr-asm.o \
-	   bin/kheap.o bin/liballoc.o bin/exec_from_file.o
+	   bin/kheap.o bin/liballoc.o bin/exec_from_file.o bin/syscalls.o
 
 # Define the compiler and assembler
 #CC = i686-elf-gcc -D__is_katauos
@@ -137,6 +137,9 @@ bin/liballoc.o: src/mm/liballoc.c
 bin/exec_from_file.o: src/tasking/exec_from_file.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
+bin/syscalls.o: src/tasking/syscalls.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
 clean:
 	rm -rf bin/
 	rm -f $(OUTPUT)

include/stdio.h

@@ -1,11 +1,15 @@
 #ifndef STDIO_H
 #define STDIO_H
 
+#include <stddef.h>
+#include <stdbool.h>
+
 //TODO: these should be contained in newlib i guess
 //but until i implement it let it be here yo
 #define EOF (-1)
 #define INT_MAX 2147483647
 
+bool print(const char* data, size_t length);
 int printf(const char* __restrict, ...);
 int putchar(int);
 int puts(const char*);

include/syscalls.h

@@ -0,0 +1,7 @@
+#ifndef SYSCALLS_H
+#define SYSCALLS_H
+#include "../include/task.h"
+
+void handle_syscall(TrapFrame *tf);
+
+#endif

include/task.h

@@ -2,6 +2,7 @@
 #define TASK_H
 
 #include <stdint.h>
+#include "../include/fat.h"
 
 // Сегменты для ядра и пользователя
 #define SEG_KCODE 0x08  // Сегмент кода ядра
@@ -14,6 +15,8 @@
 // Флаги процессора
 #define FL_IF 0x202  // Разрешить прерывания
 
+#define MAX_OPEN_FILES 32
+
 typedef enum TaskState
 {
     Ready,
@@ -58,8 +61,12 @@ typedef struct Process
     TrapFrame* tf;             // Trap frame (только для ring 3)
     uint32_t   ring;           // Уровень привилегий (0 или 3)
     struct Process* next;      // Следующий процесс
+
+    file_t* file_descriptors[MAX_OPEN_FILES];
 } Process;
 
+extern Process* current;
+
 Process* task_create(uint32_t func, uint32_t user_esp, uint32_t ring, uint32_t* pagedir);
 void     scheduler_init();
 void     schedule();

src/tasking/exec_from_file.c

@@ -68,7 +68,7 @@ void exec_from_file(const char* filename)
 
     uint8_t* file;
 
-    int result = read_file("/ebalo/testfile", &file);
+    int result = read_file("/ebalo/aaa", &file);
     debug_log("result: %X\n", result);
     debug_log("buffer: %s\n", file);
 

src/tasking/syscalls.c

@@ -0,0 +1,86 @@
+#include "../include/syscalls.h"
+#include <stddef.h>
+#include "../include/stdio.h"
+
+#define STDIN_FILENO 0
+#define STDOUT_FILENO 1
+#define STDERR_FILENO 2
+
+#define EBADF 9
+typedef unsigned short umode_t
+
+int sys_write(TrapFrame *tf)
+{
+    if(tf->ebx < 3)
+    {
+        //stdin, stdout or stderr
+        if(tf->ebx == STDOUT_FILENO)
+        {
+            print((char*)tf->ecx, tf->edx);
+            tf->ecx++;
+        }
+    }
+    else
+    {
+        if(current->file_descriptors[tf->ebx] == NULL)
+        {
+            return -EBADF;
+        }
+        return fat_fwrite(current->file_descriptors[tf->ebx], (void*)tf->ecx, tf->edx);
+    }
+}
+
+int sys_open(TrapFrame *tf)
+{
+    const char* filename = tf->ebx;
+    int flags = tf->ecx;
+    umode_t mode = tf->edx;
+
+    int fd = -1;
+
+    for(int i = 3; i < MAX_OPEN_FILES; i++)
+    {
+        if(current->file_descriptors[i] == NULL)
+        {
+            fat_fopen(current->file_descriptors[i], filename, (char)mode);
+            fd = i;
+        }
+    }
+
+    return fd;
+}
+
+int sys_close(TrapFrame *tf)
+{
+    int fd = tf->ebx;
+    if(current->file_descriptors[fd] != NULL)
+    {
+        return fat_fclose(current->file_descriptors[fd]);
+    }
+    return -1;
+}
+
+void handle_syscall(TrapFrame *tf)
+{
+    
+    debug_log("EAX: %X ", tf->eax);
+    debug_log("EBX: %X ", tf->ebx);
+    debug_log("ECX: %s ", tf->ecx);
+    debug_log("EDX: %X\n", tf->edx);
+    
+    if(tf->eax == 4)//write
+    {
+        int r = sys_write(tf);
+        tf->eax = r;
+    }
+    if(tf->eax == 5)//open
+    {
+        int r = sys_open(tf);
+        tf->eax = r;
+    }
+    if(tf->eax == 6)//close
+    {
+        int r = sys_close(tf);
+        tf->eax = r;
+    }
+}

src/tasking/task.c

@@ -18,7 +18,6 @@ uint32_t task_count;
 extern void trapret(void);
 extern void switchProcess(Process* next);
 extern Process* queue;
-extern Process* current;
 extern uint32_t pid_counter;
 extern uint32_t task_count;
 
@@ -148,11 +147,3 @@ void scheduler_init()
 
     task_create((uint32_t)idle, 0, 0, kernel_tasks_pagedir);
 }
-
-void handle_syscall(TrapFrame *tf)
-{
-    debug_log("EAX: %X ", tf->eax);
-    debug_log("EBX: %X ", tf->ebx);
-    debug_log("ECX: %s ", tf->ecx);
-    debug_log("EDX: %X\n", tf->edx);
-}

src/utils/stdio.c

@@ -69,7 +69,7 @@ void intToString(int value, char *buffer, char format) {
     buffer[i] = '\0';
 }
 
-static bool print(const char* data, size_t length) {
+bool print(const char* data, size_t length) {
 	const unsigned char* bytes = (const unsigned char*) data;
 	for (size_t i = 0; i < length; i++)
 		if (putchar(bytes[i]) == EOF)