add lab answers

labcodes_answer/lab5_result/kern/syscall/syscall.c

@@ -0,0 +1,101 @@
+#include <unistd.h>
+#include <proc.h>
+#include <syscall.h>
+#include <trap.h>
+#include <stdio.h>
+#include <pmm.h>
+#include <assert.h>
+
+static int
+sys_exit(uint32_t arg[]) {
+    int error_code = (int)arg[0];
+    return do_exit(error_code);
+}
+
+static int
+sys_fork(uint32_t arg[]) {
+    struct trapframe *tf = current->tf;
+    uintptr_t stack = tf->tf_esp;
+    return do_fork(0, stack, tf);
+}
+
+static int
+sys_wait(uint32_t arg[]) {
+    int pid = (int)arg[0];
+    int *store = (int *)arg[1];
+    return do_wait(pid, store);
+}
+
+static int
+sys_exec(uint32_t arg[]) {
+    const char *name = (const char *)arg[0];
+    size_t len = (size_t)arg[1];
+    unsigned char *binary = (unsigned char *)arg[2];
+    size_t size = (size_t)arg[3];
+    return do_execve(name, len, binary, size);
+}
+
+static int
+sys_yield(uint32_t arg[]) {
+    return do_yield();
+}
+
+static int
+sys_kill(uint32_t arg[]) {
+    int pid = (int)arg[0];
+    return do_kill(pid);
+}
+
+static int
+sys_getpid(uint32_t arg[]) {
+    return current->pid;
+}
+
+static int
+sys_putc(uint32_t arg[]) {
+    int c = (int)arg[0];
+    cputchar(c);
+    return 0;
+}
+
+static int
+sys_pgdir(uint32_t arg[]) {
+    print_pgdir();
+    return 0;
+}
+
+static int (*syscalls[])(uint32_t arg[]) = {
+    [SYS_exit]              sys_exit,
+    [SYS_fork]              sys_fork,
+    [SYS_wait]              sys_wait,
+    [SYS_exec]              sys_exec,
+    [SYS_yield]             sys_yield,
+    [SYS_kill]              sys_kill,
+    [SYS_getpid]            sys_getpid,
+    [SYS_putc]              sys_putc,
+    [SYS_pgdir]             sys_pgdir,
+};
+
+#define NUM_SYSCALLS        ((sizeof(syscalls)) / (sizeof(syscalls[0])))
+
+void
+syscall(void) {
+    struct trapframe *tf = current->tf;
+    uint32_t arg[5];
+    int num = tf->tf_regs.reg_eax;
+    if (num >= 0 && num < NUM_SYSCALLS) {
+        if (syscalls[num] != NULL) {
+            arg[0] = tf->tf_regs.reg_edx;
+            arg[1] = tf->tf_regs.reg_ecx;
+            arg[2] = tf->tf_regs.reg_ebx;
+            arg[3] = tf->tf_regs.reg_edi;
+            arg[4] = tf->tf_regs.reg_esi;
+            tf->tf_regs.reg_eax = syscalls[num](arg);
+            return ;
+        }
+    }
+    print_trapframe(tf);
+    panic("undefined syscall %d, pid = %d, name = %s.\n",
+            num, current->pid, current->name);
+}
+

labcodes_answer/lab5_result/kern/syscall/syscall.h

@@ -0,0 +1,7 @@
+#ifndef __KERN_SYSCALL_SYSCALL_H__
+#define __KERN_SYSCALL_SYSCALL_H__
+
+void syscall(void);
+
+#endif /* !__KERN_SYSCALL_SYSCALL_H__ */
+