1 #include "libc.h"
2 #include <errno.h>
3 #include <signal.h>
4 #include <spawn.h>
5 #include <stdlib.h>
6 #include <sys/wait.h>
7 #include <unistd.h>
8
system(const char * cmd)9 int system(const char* cmd) {
10 pid_t pid;
11 sigset_t old, reset;
12 struct sigaction sa = {.sa_handler = SIG_IGN}, oldint, oldquit;
13 int status = 0x7f00, ret;
14 posix_spawnattr_t attr;
15
16 if (!cmd)
17 return 1;
18
19 sigaction(SIGINT, &sa, &oldint);
20 sigaction(SIGQUIT, &sa, &oldquit);
21 sigaddset(&sa.sa_mask, SIGCHLD);
22 sigprocmask(SIG_BLOCK, &sa.sa_mask, &old);
23
24 sigemptyset(&reset);
25 if (oldint.sa_handler != SIG_IGN)
26 sigaddset(&reset, SIGINT);
27 if (oldquit.sa_handler != SIG_IGN)
28 sigaddset(&reset, SIGQUIT);
29 posix_spawnattr_init(&attr);
30 posix_spawnattr_setsigmask(&attr, &old);
31 posix_spawnattr_setsigdefault(&attr, &reset);
32 posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK);
33 ret = posix_spawn(&pid, "/bin/sh", 0, &attr, (char* []){(char*)"sh", (char*)"-c", (char*)cmd, 0}, __environ);
34 posix_spawnattr_destroy(&attr);
35
36 if (!ret)
37 while (waitpid(pid, &status, 0) < 0 && errno == EINTR)
38 ;
39 sigaction(SIGINT, &oldint, NULL);
40 sigaction(SIGQUIT, &oldquit, NULL);
41 sigprocmask(SIG_SETMASK, &old, NULL);
42
43 if (ret)
44 errno = ret;
45 return status;
46 }
47