60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
|
#include <errno.h>
|
||
|
|
#include <signal.h>
|
||
|
|
#include <sys/wait.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
int system(const char *cmdstring) {
|
||
|
|
pid_t pid;
|
||
|
|
int status;
|
||
|
|
struct sigaction ignore, saveintr, savequit;
|
||
|
|
sigset_t chldmask, savemask;
|
||
|
|
|
||
|
|
if (cmdstring == NULL)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
ignore.sa_handler = SIG_IGN;
|
||
|
|
sigemptyset(&ignore.sa_mask);
|
||
|
|
ignore.sa_flags = 0;
|
||
|
|
if (sigaction(SIGINT, &ignore, &saveintr) < 0)
|
||
|
|
return -1;
|
||
|
|
if (sigaction(SIGQUIT, &ignore, &savequit) < 0)
|
||
|
|
return -1;
|
||
|
|
sigemptyset(&chldmask);
|
||
|
|
sigaddset(&chldmask, SIGCHLD);
|
||
|
|
if (sigprocmask(SIG_BLOCK, &chldmask, &savemask) < 0)
|
||
|
|
return -1;
|
||
|
|
|
||
|
|
if((pid = fork()) < 0) {
|
||
|
|
status = -1;
|
||
|
|
}
|
||
|
|
else if (pid == 0) {
|
||
|
|
sigaction(SIGINT, &saveintr, NULL);
|
||
|
|
sigaction(SIGQUIT, &savequit, NULL);
|
||
|
|
execl("/bin/sh", "sh", "-c", cmdstring, (char *)0);
|
||
|
|
_exit(127);
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
while (waitpid(pid, &status, 0) < 0)
|
||
|
|
if (errno != EINTR) {
|
||
|
|
return -1;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if(sigaction(SIGINT, &saveintr, NULL) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if(sigaction(SIGQUIT, &savequit, NULL) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
if(sigprocmask(SIG_SETMASK, &savemask, NULL) < 0) {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return status;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(void) {
|
||
|
|
return system("ls .");
|
||
|
|
}
|