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Shell Lab: trace09-10

This commit is contained in:
cyp0633 2022-05-25 20:33:10 +08:00
parent ab00d9b9ce
commit df26291a85
Signed by: cyp0633
GPG Key ID: E1BC508A994A5138
1 changed files with 59 additions and 1 deletions
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60
shlab/tsh.c
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@ -281,7 +281,12 @@ int builtin_cmd(char **argv)
listjobs(jobs);
return 1; // this IS a builtin command, return 1 to notify
}
return 0; /* not a builtin command */
if (strcmp(argv[0], "bg") == 0 || strcmp(argv[0], "fg") == 0) // judge bg & fg
{
do_bgfg(argv);
return 1;
}
return 0; /* not a builtin command */
}
/*
@ -289,6 +294,59 @@ int builtin_cmd(char **argv)
*/
void do_bgfg(char **argv)
{
char *id = argv[1], *end; // JID or PID
struct job_t *job;
int numid;
// extract job or process
if (id == NULL) // not specified
{
printf("%s command requires PID or %%jobid argument\n", argv[0]);
return;
}
if (id[0] == '%') // this is a job
{
id++; // point to the number position
numid = strtol(id, &end, 10); // convert id char[] to integer
if (*end != '\0') // contains non-digit numbers
{
printf("%s: argument must be a PID or %%jobid\n", argv[0]);
return;
}
job = getjobjid(jobs, numid); // try to get job
if (job == NULL)
{
printf("%%%d: No such job\n", numid);
return;
}
}
else // this is a process
{
numid = strtol(id, &end, 10);
if (*end != '\0')
{
printf("%s: argument must be a PID or %%jobid\n", argv[0]);
return;
}
job = getjobpid(jobs, numid); // try to get proc
if (job == NULL)
{
printf("(%d): No such process\n", atoi(id));
return;
}
}
// send signal
kill(-(job->pid), SIGCONT);
// process according to bg/fg
if (strcmp(argv[0], "fg") == 0) // foreground
{
job->state = FG;
waitfg(job->pid);
}
else // background
{
job->state = BG;
printf("[%d] (%d) %s", job->jid, job->pid, job->cmdline);
}
return;
}