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Add posix_spawn (#114)

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Justine Tunney 2021-03-07 20:14:07 -08:00
parent 5f088cec23
commit 5ce83b08c8
10 changed files with 521 additions and 22 deletions
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117
libc/stdio/spawn.c Normal file
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@ -0,0 +1,117 @@
/*-*- 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 2021 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/calls/calls.h"
#include "libc/calls/scheduler.h"
#include "libc/calls/sigbits.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/errno.h"
#include "libc/fmt/fmt.h"
#include "libc/stdio/spawn.h"
#include "libc/stdio/spawna.internal.h"
#include "libc/str/str.h"
/**
* Spawns process the POSIX way.
*
* @param pid is non-NULL and will be set to child pid in parent
* @param path of executable that is not PATH searched
* @return 0 on success or error number on failure
*/
int posix_spawn(int *pid, const char *path,
const posix_spawn_file_actions_t *file_actions,
const posix_spawnattr_t *attrp, char *const argv[],
char *const envp[]) {
unsigned mode;
sigset_t allsigs;
struct sigaction dfl;
char *p, *q, opath[PATH_MAX];
int s, fd, newfd, oflag, tempfd;
if (!(*pid = vfork())) {
if (attrp) {
if (attrp->posix_attr_flags & POSIX_SPAWN_SETPGROUP) {
if (setpgid(0, attrp->posix_attr_pgroup)) _exit(127);
}
if (attrp->posix_attr_flags & POSIX_SPAWN_SETSIGMASK) {
sigprocmask(SIG_SETMASK, &attrp->posix_attr_sigmask, NULL);
}
if (attrp->posix_attr_flags & POSIX_SPAWN_RESETIDS) {
setuid(getuid());
setgid(getgid());
}
if (attrp->posix_attr_flags & POSIX_SPAWN_SETSIGDEF) {
dfl.sa_handler = SIG_DFL;
dfl.sa_flags = 0;
sigfillset(&allsigs);
for (s = 0; sigismember(&allsigs, s); s++) {
if (sigismember(&attrp->posix_attr_sigdefault, s)) {
if (sigaction(s, &dfl, NULL) == -1) _exit(127);
}
}
}
}
if (file_actions) {
p = *file_actions;
while (*p != '\0') {
if (!strncmp(p, "close(", 6)) {
if (sscanf(p + 6, "%d)", &fd) != 1) _exit(127);
if (close(fd) == -1) _exit(127);
} else if (!strncmp(p, "dup2(", 5)) {
if (sscanf(p + 5, "%d,%d)", &fd, &newfd) != 2) _exit(127);
if (dup2(fd, newfd) == -1) _exit(127);
} else if (!strncmp(p, "open(", 5)) {
if (sscanf(p + 5, "%d,", &fd) != 1) _exit(127);
p = strchr(p, ',') + 1;
q = strchr(p, '*');
if (!q || q - p + 1 > PATH_MAX) _exit(127);
strncpy(opath, p, q - p);
opath[q - p] = '\0';
if (sscanf(q + 1, "%o,%o)", &oflag, &mode) != 2) _exit(127);
if (close(fd) == -1 && errno != EBADF) _exit(127);
tempfd = open(opath, oflag, mode);
if (tempfd == -1) _exit(127);
if (tempfd != fd) {
if (dup2(tempfd, fd) == -1) _exit(127);
if (close(tempfd) == -1) _exit(127);
}
} else {
_exit(127);
}
p = strchr(p, ')') + 1;
}
}
if (attrp) {
if (attrp->posix_attr_flags & POSIX_SPAWN_SETSCHEDULER) {
if (sched_setscheduler(0, attrp->posix_attr_schedpolicy,
&attrp->posix_attr_schedparam) == -1) {
_exit(127);
}
}
if (attrp->posix_attr_flags & POSIX_SPAWN_SETSCHEDPARAM) {
if (sched_setparam(0, &attrp->posix_attr_schedparam) == -1) {
_exit(127);
}
}
}
execve(path, argv, envp);
_exit(127);
} else {
if (*pid == -1) return errno;
return 0;
}
}