NetBSD/lib/libc/gen/popen.c

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/* $NetBSD: popen.c,v 1.25 2000/01/22 22:19:11 mycroft Exp $ */
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/*
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* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
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*
* This code is derived from software written by Ken Arnold and
* published in UNIX Review, Vol. 6, No. 8.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
#if 0
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static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
#else
__RCSID("$NetBSD: popen.c,v 1.25 2000/01/22 22:19:11 mycroft Exp $");
#endif
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#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
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#include <sys/param.h>
#include <sys/wait.h>
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#include <sys/socket.h>
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#include <assert.h>
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#include <errno.h>
#include <paths.h>
#include <signal.h>
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
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#ifdef __weak_alias
__weak_alias(popen,_popen)
__weak_alias(pclose,_pclose)
#endif
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static struct pid {
struct pid *next;
FILE *fp;
pid_t pid;
} *pidlist;
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FILE *
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popen(command, type)
const char *command, *type;
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{
struct pid *cur, *old;
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FILE *iop;
int pdes[2], pid, twoway, serrno;
_DIAGASSERT(command != NULL);
_DIAGASSERT(type != NULL);
#ifdef __GNUC__
/* This outrageous construct just to shut up a GCC warning. */
(void) &cur; (void) &twoway; (void) &type;
#endif
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if (strchr(type, '+')) {
twoway = 1;
type = "r+";
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if (socketpair(AF_LOCAL, SOCK_STREAM, 0, pdes) < 0)
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return (NULL);
} else {
twoway = 0;
if ((*type != 'r' && *type != 'w') || type[1] ||
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(pipe(pdes) < 0)) {
errno = EINVAL;
return (NULL);
}
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}
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if ((cur = malloc(sizeof(struct pid))) == NULL) {
(void)close(pdes[0]);
(void)close(pdes[1]);
errno = ENOMEM;
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return (NULL);
}
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switch (pid = vfork()) {
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case -1: /* Error. */
serrno = errno;
free(cur);
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(void)close(pdes[0]);
(void)close(pdes[1]);
errno = serrno;
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return (NULL);
/* NOTREACHED */
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case 0: /* Child. */
/* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
from previous popen() calls that remain open in the
parent process are closed in the new child process. */
for (old = pidlist; old; old = old->next)
close(fileno(old->fp)); /* don't allow a flush */
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if (*type == 'r') {
(void)close(pdes[0]);
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if (pdes[1] != STDOUT_FILENO) {
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(void)dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
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}
if (twoway)
(void)dup2(STDOUT_FILENO, STDIN_FILENO);
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} else {
(void)close(pdes[1]);
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if (pdes[0] != STDIN_FILENO) {
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(void)dup2(pdes[0], STDIN_FILENO);
(void)close(pdes[0]);
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}
}
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execl(_PATH_BSHELL, "sh", "-c", command, NULL);
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_exit(127);
/* NOTREACHED */
}
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/* Parent; assume fdopen can't fail. */
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if (*type == 'r') {
iop = fdopen(pdes[0], type);
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(void)close(pdes[1]);
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} else {
iop = fdopen(pdes[1], type);
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(void)close(pdes[0]);
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}
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/* Link into list of file descriptors. */
cur->fp = iop;
cur->pid = pid;
cur->next = pidlist;
pidlist = cur;
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return (iop);
}
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/*
* pclose --
* Pclose returns -1 if stream is not associated with a `popened' command,
* if already `pclosed', or waitpid returns an error.
*/
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int
pclose(iop)
FILE *iop;
{
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struct pid *cur, *last;
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int pstat;
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pid_t pid;
_DIAGASSERT(iop != NULL);
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/* Find the appropriate file pointer. */
for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
if (cur->fp == iop)
break;
if (cur == NULL)
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return (-1);
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(void)fclose(iop);
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do {
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pid = waitpid(cur->pid, &pstat, 0);
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} while (pid == -1 && errno == EINTR);
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/* Remove the entry from the linked list. */
if (last == NULL)
pidlist = cur->next;
else
last->next = cur->next;
free(cur);
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return (pid == -1 ? -1 : pstat);
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}