147 lines
3.0 KiB
C
147 lines
3.0 KiB
C
#include <assert.h>
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#include <kern/fs.h>
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#include <kern/process.h>
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#include <kern/syscall.h>
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#include <kern/time.h>
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static ssize_t sys_get_ticks(void);
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static ssize_t sys_get_pid(void);
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static ssize_t sys_read(void);
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static ssize_t sys_write(void);
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static ssize_t sys_exec(void);
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static ssize_t sys_fork(void);
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static ssize_t sys_wait(void);
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static ssize_t sys_exit(void);
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static ssize_t sys_fork_ack(void);
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ssize_t (*syscall_table[])(void) = {
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[_NR_get_ticks] sys_get_ticks,
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[_NR_get_pid] sys_get_pid,
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[_NR_read] sys_read,
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[_NR_write] sys_write,
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[_NR_exec] sys_exec,
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[_NR_fork] sys_fork,
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[_NR_wait] sys_wait,
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[_NR_exit] sys_exit,
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[_NR_fork_ack] sys_fork_ack,
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};
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/*
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* 获取系统调用参数
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* 系统调用最多会使用6个参数
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* 0 1 2 3 4 5
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* ebx ecx edx esi edi ebp
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*/
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static u32
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get_arg(int order)
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{
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switch (order) {
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case 0:
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return p_proc_ready->pcb.user_regs.ebx;
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case 1:
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return p_proc_ready->pcb.user_regs.ecx;
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case 2:
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return p_proc_ready->pcb.user_regs.edx;
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case 3:
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return p_proc_ready->pcb.user_regs.esi;
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case 4:
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return p_proc_ready->pcb.user_regs.edi;
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case 5:
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return p_proc_ready->pcb.user_regs.ebp;
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default:
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panic("invalid order! order: %d", order);
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}
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}
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/*
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* ssize_t get_ticks(void)
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* 获取当前的时间戳
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*/
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static ssize_t
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sys_get_ticks(void)
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{
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return do_get_ticks();
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}
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/*
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* int get_pid(void)
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* 获取当前进程的进程号
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*/
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static ssize_t
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sys_get_pid(void)
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{
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return do_get_pid();
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}
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/*
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* ssize_t read(int fd, void *buf, size_t count)
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* 目前在这个实验中这个系统调用的作用是从键盘中得到输入
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* 写入用户进程中以buf为开头的长度为count字节的缓冲区，返回值为写入的字节数
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*/
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static ssize_t
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sys_read(void)
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{
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return do_read(get_arg(0), (void *)get_arg(1), get_arg(2));
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}
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/*
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* ssize_t write(int fd, const void *buf, size_t count)
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* 目前在这个实验中这个系统调用的作用是往终端输出字符
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* 输出用户进程中以buf为开头的长度为count字节的缓冲区，返回值为写出去的字节数
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*/
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static ssize_t
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sys_write(void)
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{
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return do_write(get_arg(0), (const void *)get_arg(1), get_arg(2));
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}
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/*
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* ssize_t exec(const char *pathname)
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* 在进程中启动另一个程序执行的方法，加载为pathname对应的ELF文件
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*/
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static ssize_t
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sys_exec(void)
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{
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return do_exec((const void *)get_arg(0));
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}
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/*
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* ssize_t fork(void)
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* 复制一个一模一样的进程
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*/
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static ssize_t
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sys_fork(void)
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{
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return do_fork();
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}
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/*
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* ssize_t wait(int *wstatus)
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* 等待子进程exit，回收子进程资源，wstatus接收子进程的返回码
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*/
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static ssize_t
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sys_wait(void)
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{
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return do_wait((int *)get_arg(0));
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}
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/*
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* ssize_t exit(int status)
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* 进程退出的方法，将status作为返回码传递给父进程
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*/
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static ssize_t
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sys_exit(void)
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{
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return do_exit(get_arg(0));
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}
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/*
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* ssize_t fork_ack(void)
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* forkbomb.c所用，用于检测成功fork的次数
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* 内部实现被封装不公开
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*/
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static ssize_t
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sys_fork_ack(void)
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{
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return do_fork_ack();
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} |