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shell lab实验因为要执行多个测试文本，故写了一个执行带脚本test.sh，执行从make test01到16，方便测试，仅供参考
tset.sh内容如下
#! /bin/bash
for loop in 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16
do
echo $loop
echo ''
str=$(make test$loop)
# len=${#str}
echo "$str"
# echo $(make test$loop)
echo '----------------------------------------'
done
exit 0
?tes.c内容如下
/*
* tsh - A tiny shell program with job control
*
* <Put your name and login ID here>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
/* Misc manifest constants */
#define MAXLINE 1024 /* max line size */
#define MAXARGS 128 /* max args on a command line */
#define MAXJOBS 16 /* max jobs at any point in time */
#define MAXJID 1<<16 /* max job ID */
/* Job states */
#define UNDEF 0 /* undefined */
#define FG 1 /* running in foreground */
#define BG 2 /* running in background */
#define ST 3 /* stopped */
/*
* Jobs states: FG (foreground), BG (background), ST (stopped)
* Job state transitions and enabling actions:
* FG -> ST : ctrl-z
* ST -> FG : fg command
* ST -> BG : bg command
* BG -> FG : fg command
* At most 1 job can be in the FG state.
*/
/* Global variables */
extern char **environ; /* defined in libc */
char prompt[] = "tsh> "; /* command line prompt (DO NOT CHANGE) */
int verbose = 0; /* if true, print additional output */
int nextjid = 1; /* next job ID to allocate */
char sbuf[MAXLINE]; /* for composing sprintf messages */
struct job_t { /* The job struct */
pid_t pid; /* job PID */
int jid; /* job ID [1, 2, ...] */
int state; /* UNDEF, BG, FG, or ST */
char cmdline[MAXLINE]; /* command line */
};
struct job_t jobs[MAXJOBS]; /* The job list */
/* End global variables */
/* Function prototypes */
/* Here are the functions that you will implement */
void eval(char *cmdline);
int builtin_cmd(char **argv);
void do_bgfg(char **argv);
void waitfg(pid_t pid);
void sigchld_handler(int sig);
void sigtstp_handler(int sig);
void sigint_handler(int sig);
/* Here are helper routines that we've provided for you */
int parseline(const char *cmdline, char **argv);
void sigquit_handler(int sig);
void clearjob(struct job_t *job);
void initjobs(struct job_t *jobs);
int maxjid(struct job_t *jobs);
int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline);
int deletejob(struct job_t *jobs, pid_t pid);
pid_t fgpid(struct job_t *jobs);
struct job_t *getjobpid(struct job_t *jobs, pid_t pid);
struct job_t *getjobjid(struct job_t *jobs, int jid);
int pid2jid(pid_t pid);
void listjobs(struct job_t *jobs);
void usage(void);
void unix_error(char *msg);
void app_error(char *msg);
typedef void handler_t(int);
handler_t *Signal(int signum, handler_t *handler);
/*
* main - The shell's main routine
*/
int main(int argc, char **argv)
{
char c;
char cmdline[MAXLINE];
int emit_prompt = 1; /* emit prompt (default) */
/* Redirect stderr to stdout (so that driver will get all output
* on the pipe connected to stdout) */
dup2(1, 2);
/* Parse the command line */
while ((c = getopt(argc, argv, "hvp")) != EOF) {
switch (c) {
case 'h': /* print help message */
usage();
break;
case 'v': /* emit additional diagnostic info */
verbose = 1;
break;
case 'p': /* don't print a prompt */
emit_prompt = 0; /* handy for automatic testing */
break;
default:
usage();
}
}
/* Install the signal handlers */
/* These are the ones you will need to implement */
Signal(SIGINT, sigint_handler); /* ctrl-c */
Signal(SIGTSTP, sigtstp_handler); /* ctrl-z */
Signal(SIGCHLD, sigchld_handler); /* Terminated or stopped child */
/* This one provides a clean way to kill the shell */
Signal(SIGQUIT, sigquit_handler);
/* Initialize the job list */
initjobs(jobs);
/* Execute the shell's read/eval loop */
while (1) {
/* Read command line */
if (emit_prompt) {
printf("%s", prompt);
fflush(stdout);
}
if ((fgets(cmdline, MAXLINE, stdin) == NULL) && ferror(stdin))
app_error("fgets error");
if (feof(stdin)) { /* End of file (ctrl-d) */
fflush(stdout);
exit(0);
}
/* Evaluate the command line */
eval(cmdline);
fflush(stdout);
fflush(stdout);
}
exit(0); /* control never reaches here */
}
/*
* eval - Evaluate the command line that the user has just typed in
*
* If the user has requested a built-in command (quit, jobs, bg or fg)
* then execute it immediately. Otherwise, fork a child process and
* run the job in the context of the child. If the job is running in
* the foreground, wait for it to terminate and then return. Note:
* each child process must have a unique process group ID so that our
* background children don't receive SIGINT (SIGTSTP) from the kernel
* when we type ctrl-c (ctrl-z) at the keyboard.
*/
void eval(char *cmdline)
{
char *argv[MAXARGS];
char buf[MAXLINE];
int bg;
int state;
pid_t pid;
sigset_t mask_all, mask_one, prev;
strcpy(buf, cmdline);
bg = parseline(buf, argv);
// 没有参数就退出
// 其实可以加一个判断参数数量是否正确的语句，比较完整
if (argv[0] == NULL)
return ;
// 如果不是内置的命令，则执行
if(!builtin_cmd(argv))
{
// 在函数内部加阻塞列表，不然之后可能会出现不痛不痒的bug
sigfillset(&mask_all);
sigemptyset(&mask_one);
sigaddset(&mask_one, SIGCHLD);
// 为了避免父进程运行到addjob之前子进程就退出了，所以
// 在fork子进程前阻塞sigchld信号，addjob后解除
sigprocmask(SIG_BLOCK, &mask_one, &prev);
if ((pid = fork()) == 0)
{
// 子进程继承了父进程的阻塞向量，也要解除阻塞，
// 避免收不到它本身的子进程的信号
sigprocmask(SIG_SETMASK, &prev, NULL);
// 改进程组与自己pid一样
if (setpgid(0, 0) < 0)
{
perror("SETPGID ERROR");
exit(0);
}
// 正常运行execve函数会替换内存，不会返回/退出，所以必须要加exit，
// 否则会一直运行下去，子进程会开始运行父进程的代码
if (execve(argv[0], argv, environ) < 0)
{
printf("%s: Command not found\n", argv[0]);
exit(0);
}
}
else
{
state = bg ? BG : FG;
// 依然是加塞，阻塞所有信号
sigprocmask(SIG_BLOCK, &mask_all, NULL);
addjob(jobs, pid, state, cmdline);
sigprocmask(SIG_SETMASK, &prev, NULL);
}
// 后台则打印，前台则等待子进程结束
if (!bg)
waitfg(pid);
else
printf("[%d] (%d) %s",pid2jid(pid), pid, cmdline);
// 后面又想了想，打印后台的时候其实走的是全局变量，也应该加塞才对，
// 应该是所有的用到全局变量的都应该加塞，但是懒，不改了，知道就行
}
return;
}
/*
* parseline - Parse the command line and build the argv array.
*
* Characters enclosed in single quotes are treated as a single
* argument. Return true if the user has requested a BG job, false if
* the user has requested a FG job.
*/
int parseline(const char *cmdline, char **argv)
{
static char array[MAXLINE]; /* holds local copy of command line */
char *buf = array; /* ptr that traverses command line */
char *delim; /* points to first space delimiter */
int argc; /* number of args */
int bg; /* background job? */
strcpy(buf, cmdline);
buf[strlen(buf)-1] = ' '; /* replace trailing '\n' with space */
while (*buf && (*buf == ' ')) /* ignore leading spaces */
buf++;
/* Build the argv list */
argc = 0;
if (*buf == '\'') {
buf++;
delim = strchr(buf, '\'');
}
else {
delim = strchr(buf, ' ');
}
while (delim) {
argv[argc++] = buf;
*delim = '\0';
buf = delim + 1;
while (*buf && (*buf == ' ')) /* ignore spaces */
buf++;
if (*buf == '\'') {
buf++;
delim = strchr(buf, '\'');
}
else {
delim = strchr(buf, ' ');
}
}
argv[argc] = NULL;
if (argc == 0) /* ignore blank line */
return 1;
/* should the job run in the background? */
if ((bg = (*argv[argc-1] == '&')) != 0) {
argv[--argc] = NULL;
}
return bg;
}
/*
* builtin_cmd - If the user has typed a built-in command then execute
* it immediately.
*/
int builtin_cmd(char **argv)
{
// 判断是不是内置函数，不是就返回，注意内置命令有要继续操作的一定
// 要返回1，不是内置函数就是0
if (!strcmp(argv[0], "quit"))
exit(0);
else if (!strcmp(argv[0], "jobs"))
{
listjobs(jobs);
return 1;
}
else if (!strcmp(argv[0], "bg") || !strcmp(argv[0], "fg"))
{
do_bgfg(argv);
return 1;
}
// 对单独的&不处理
else if (!strcmp(argv[0], "&"))
{
return 1;
}
return 0; /* not a builtin command */
}
/*
* do_bgfg - Execute the builtin bg and fg commands
*/
void do_bgfg(char **argv)
{
// 没有参数，其实应该也加上判断参数个数的语句才比较完整
if (argv[1] == NULL)
{
printf("%s command requires PID or %%jobid argument\n", argv[0]);
return;
}
struct job_t* job;
int id;
// bg %5 和bg 5不一样,一个是对一个作业操作，另一个是对进程操作，
// 而作业代表了一个进程组。
// 要根据tshref的样例输出看有多少种情况
// 读到jid
if (sscanf(argv[1], "%%%d", &id) > 0)
{
job = getjobjid(jobs, id);
if (job == NULL)
{
printf("%%%d: No such job\n", id);
return ;
}
}
// 读到pid
else if (sscanf(argv[1], "%d", &id) > 0)
{
job = getjobpid(jobs, id);
if (job == NULL)
{
printf("(%d): No such process\n", id);
return ;
}
}
// 格式错误
else
{
printf("%s: argument must be a PID or %%jobid\n", argv[0]);
return;
}
// 因为子进程单独成组，所以kill很方便
if(!strcmp(argv[0], "bg"))
{
// 进程组是负数pid，发送信号并更改状态
kill(-(job->pid), SIGCONT);
job->state = BG;
printf("[%d] (%d) %s",job->jid, job->pid, job->cmdline);
}
else
{
// 如果fg后台进程，那么将它的状态转为前台进程，然后等待它终止
kill(-(job->pid), SIGCONT);
job->state = FG;
waitfg(job->pid);
}
return;
}
/*
* waitfg - Block until process pid is no longer the foreground process
*/
void waitfg(pid_t pid)
{
// 进程回收不需要做，只要等待前台进程就行
sigset_t mask_temp;
sigemptyset(&mask_temp);
// 设定不阻塞任何信号
// 其实可以直接sleep显式等待信号
while (fgpid(jobs) > 0)
sigsuspend(&mask_temp);
return;
}
/*****************
* Signal handlers
*****************/
/*
* sigchld_handler - The kernel sends a SIGCHLD to the shell whenever
* a child job terminates (becomes a zombie), or stops because it
* received a SIGSTOP or SIGTSTP signal. The handler reaps all
* available zombie children, but doesn't wait for any other
* currently running children to terminate.
*/
void sigchld_handler(int sig)
{
int olderrno = errno; // 保存旧errno
pid_t pid;
int status;
sigset_t mask_all, prev;
sigfillset(&mask_all); // 设置全阻塞
while((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0)
{
// WNOHANG | WUNTRACED 是立即返回
// 用WIFEXITED(status)，WIFSIGNALED(status)，WIFSTOPPED(status)等来补获终止或者
// 被停止的子进程的退出状态。
if (WIFEXITED(status)) // 正常退出 delete
{
sigprocmask(SIG_BLOCK, &mask_all, &prev);
deletejob(jobs, pid);
sigprocmask(SIG_SETMASK, &prev, NULL);
}
else if (WIFSIGNALED(status)) // 信号退出 delete
{
struct job_t* job = getjobpid(jobs, pid);
sigprocmask(SIG_BLOCK, &mask_all, &prev);
printf("Job [%d] (%d) terminated by signal %d\n", job->jid, job->pid, WTERMSIG(status));
deletejob(jobs, pid);
sigprocmask(SIG_SETMASK, &prev, NULL);
}
else // 停止 只修改状态就行
{
struct job_t* job = getjobpid(jobs, pid);
sigprocmask(SIG_BLOCK, &mask_all, &prev);
printf("Job [%d] (%d) stopped by signal %d\n", job->jid, job->pid, WSTOPSIG(status));
job->state= ST;
sigprocmask(SIG_SETMASK, &prev, NULL);
}
}
errno = olderrno; // 恢复
return;
}
/*
* sigint_handler - The kernel sends a SIGINT to the shell whenver the
* user types ctrl-c at the keyboard. Catch it and send it along
* to the foreground job.
*/
void sigint_handler(int sig)
{
// 向子进程发送信号即可
int olderrno = errno;
pid_t pid = fgpid(jobs);
if (pid != 0)
kill(-pid, sig);
errno = olderrno;
return;
}
/*
* sigtstp_handler - The kernel sends a SIGTSTP to the shell whenever
* the user types ctrl-z at the keyboard. Catch it and suspend the
* foreground job by sending it a SIGTSTP.
*/
void sigtstp_handler(int sig)
{
// 向子进程发送信号即可
int olderrno = errno;
pid_t pid = fgpid(jobs);
if (pid != 0)
kill(-pid, sig);
errno = olderrno;
return;
}
/*********************
* End signal handlers
*********************/
/***********************************************
* Helper routines that manipulate the job list
**********************************************/
/* clearjob - Clear the entries in a job struct */
void clearjob(struct job_t *job) {
job->pid = 0;
job->jid = 0;
job->state = UNDEF;
job->cmdline[0] = '\0';
}
/* initjobs - Initialize the job list */
void initjobs(struct job_t *jobs) {
int i;
for (i = 0; i < MAXJOBS; i++)
clearjob(&jobs[i]);
}
/* maxjid - Returns largest allocated job ID */
int maxjid(struct job_t *jobs)
{
int i, max=0;
for (i = 0; i < MAXJOBS; i++)
if (jobs[i].jid > max)
max = jobs[i].jid;
return max;
}
/* addjob - Add a job to the job list */
int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline)
{
int i;
if (pid < 1)
return 0;
for (i = 0; i < MAXJOBS; i++) {
if (jobs[i].pid == 0) {
jobs[i].pid = pid;
jobs[i].state = state;
jobs[i].jid = nextjid++;
if (nextjid > MAXJOBS)
nextjid = 1;
strcpy(jobs[i].cmdline, cmdline);
if(verbose){
printf("Added job [%d] %d %s\n", jobs[i].jid, jobs[i].pid, jobs[i].cmdline);
}
return 1;
}
}
printf("Tried to create too many jobs\n");
return 0;
}
/* deletejob - Delete a job whose PID=pid from the job list */
int deletejob(struct job_t *jobs, pid_t pid)
{
int i;
if (pid < 1)
return 0;
for (i = 0; i < MAXJOBS; i++) {
if (jobs[i].pid == pid) {
clearjob(&jobs[i]);
nextjid = maxjid(jobs)+1;
return 1;
}
}
return 0;
}
/* fgpid - Return PID of current foreground job, 0 if no such job */
pid_t fgpid(struct job_t *jobs) {
int i;
for (i = 0; i < MAXJOBS; i++)
if (jobs[i].state == FG)
return jobs[i].pid;
return 0;
}
/* getjobpid - Find a job (by PID) on the job list */
struct job_t *getjobpid(struct job_t *jobs, pid_t pid) {
int i;
if (pid < 1)
return NULL;
for (i = 0; i < MAXJOBS; i++)
if (jobs[i].pid == pid)
return &jobs[i];
return NULL;
}
/* getjobjid - Find a job (by JID) on the job list */
struct job_t *getjobjid(struct job_t *jobs, int jid)
{
int i;
if (jid < 1)
return NULL;
for (i = 0; i < MAXJOBS; i++)
if (jobs[i].jid == jid)
return &jobs[i];
return NULL;
}
/* pid2jid - Map process ID to job ID */
int pid2jid(pid_t pid)
{
int i;
if (pid < 1)
return 0;
for (i = 0; i < MAXJOBS; i++)
if (jobs[i].pid == pid) {
return jobs[i].jid;
}
return 0;
}
/* listjobs - Print the job list */
void listjobs(struct job_t *jobs)
{
int i;
for (i = 0; i < MAXJOBS; i++) {
if (jobs[i].pid != 0) {
printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid);
switch (jobs[i].state) {
case BG:
printf("Running ");
break;
case FG:
printf("Foreground ");
break;
case ST:
printf("Stopped ");
break;
default:
printf("listjobs: Internal error: job[%d].state=%d ",
i, jobs[i].state);
}
printf("%s", jobs[i].cmdline);
}
}
}
/******************************
* end job list helper routines
******************************/
/***********************
* Other helper routines
***********************/
/*
* usage - print a help message
*/
void usage(void)
{
printf("Usage: shell [-hvp]\n");
printf(" -h print this message\n");
printf(" -v print additional diagnostic information\n");
printf(" -p do not emit a command prompt\n");
exit(1);
}
/*
* unix_error - unix-style error routine
*/
void unix_error(char *msg)
{
fprintf(stdout, "%s: %s\n", msg, strerror(errno));
exit(1);
}
/*
* app_error - application-style error routine
*/
void app_error(char *msg)
{
fprintf(stdout, "%s\n", msg);
exit(1);
}
/*
* Signal - wrapper for the sigaction function
*/
handler_t *Signal(int signum, handler_t *handler)
{
struct sigaction action, old_action;
action.sa_handler = handler;
sigemptyset(&action.sa_mask); /* block sigs of type being handled */
action.sa_flags = SA_RESTART; /* restart syscalls if possible */
if (sigaction(signum, &action, &old_action) < 0)
unix_error("Signal error");
return (old_action.sa_handler);
}
/*
* sigquit_handler - The driver program can gracefully terminate the
* child shell by sending it a SIGQUIT signal.
*/
void sigquit_handler(int sig)
{
printf("Terminating after receipt of SIGQUIT signal\n");
exit(1);
}
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