cosmopolitan/libc/stdio/system.c
2021-03-05 06:09:12 -08:00

77 lines
3.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/sigbits.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/paths.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/ok.h"
#include "libc/sysv/consts/sig.h"
/**
* Launches program with system command interpreter.
*
* @param cmdline is an interpreted Turing-complete command
* @return -1 if child process couldn't be created, otherwise a wait
* status that can be accessed using macros like WEXITSTATUS(s)
*/
int system(const char *cmdline) {
int pid, wstatus;
sigset_t chldmask, savemask;
struct sigaction ignore, saveint, savequit;
if (!cmdline) {
if (IsWindows()) return 1;
if (access(_PATH_BSHELL, X_OK) == 0) return 1;
return 0;
}
ignore.sa_flags = 0;
ignore.sa_handler = SIG_IGN;
sigemptyset(&ignore.sa_mask);
sigaction(SIGINT, &ignore, &saveint);
sigaction(SIGQUIT, &ignore, &savequit);
sigemptyset(&chldmask);
sigaddset(&chldmask, SIGCHLD);
sigprocmask(SIG_BLOCK, &chldmask, &savemask);
if (!(pid = fork())) {
sigaction(SIGINT, &saveint, NULL);
sigaction(SIGQUIT, &savequit, NULL);
sigprocmask(SIG_SETMASK, &savemask, NULL);
systemexec(cmdline);
_exit(127);
} else if (pid != -1) {
while (wait4(pid, &wstatus, 0, NULL) == -1) {
if (errno != EINTR) {
wstatus = -1;
break;
}
}
} else {
wstatus = -1;
}
sigaction(SIGINT, &saveint, NULL);
sigaction(SIGQUIT, &savequit, NULL);
sigprocmask(SIG_SETMASK, &savemask, NULL);
return wstatus;
}