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/*-*- 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/errno.h"
#include "libc/paths.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/internal.h"
#include "libc/stdio/stdio.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
/**
* Spawns subprocess and returns pipe stream.
* @see pclose()
*/
FILE *popen(const char *cmdline, const char *mode) {
FILE *f;
int dir, flags, pipefds[2];
flags = fopenflags(mode);
if ((flags & O_ACCMODE) == O_RDONLY) {
dir = 0;
} else if ((flags & O_ACCMODE) == O_WRONLY) {
dir = 1;
} else {
errno = EINVAL;
return NULL;
}
if (pipe(pipefds) == -1) return NULL;
fcntl(pipefds[dir], F_SETFD, FD_CLOEXEC);
if (!(f = fdopen(pipefds[dir], mode))) abort();
if ((f->pid = vfork()) == -1) abort();
if (!f->pid) {
dup2(pipefds[!dir], !dir);
systemexec(cmdline);
_exit(127);
}
close(pipefds[!dir]);
return f;
}
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