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/* $NetBSD: popen.c,v 1.32 2012/06/25 22:32:43 abs Exp $ */
/*
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* 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. 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>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
#else
__RCSID("$NetBSD: popen.c,v 1.32 2012/06/25 22:32:43 abs Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/param.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <assert.h>
#include <errno.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "env.h"
#include "reentrant.h"
#ifdef __weak_alias
__weak_alias(popen,_popen)
__weak_alias(pclose,_pclose)
#endif
static struct pid {
struct pid *next;
FILE *fp;
#ifdef _REENTRANT
int fd;
#endif
pid_t pid;
} *pidlist;
#ifdef _REENTRANT
static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
#endif
FILE *
popen(const char *command, const char *type)
{
struct pid *cur, *old;
FILE *iop;
const char * volatile xtype = type;
int pdes[2], pid, serrno;
volatile int twoway;
int flags;
_DIAGASSERT(command != NULL);
_DIAGASSERT(xtype != NULL);
flags = strchr(xtype, 'e') ? O_CLOEXEC : 0;
if (strchr(xtype, '+')) {
int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
twoway = 1;
xtype = "r+";
if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
return NULL;
} else {
twoway = 0;
xtype = strrchr(xtype, 'r') ? "r" : "w";
if (pipe2(pdes, flags) == -1)
return NULL;
}
if ((cur = malloc(sizeof(struct pid))) == NULL) {
(void)close(pdes[0]);
(void)close(pdes[1]);
errno = ENOMEM;
return (NULL);
}
(void)rwlock_rdlock(&pidlist_lock);
(void)__readlockenv();
switch (pid = vfork()) {
case -1: /* Error. */
serrno = errno;
(void)__unlockenv();
(void)rwlock_unlock(&pidlist_lock);
free(cur);
(void)close(pdes[0]);
(void)close(pdes[1]);
errno = serrno;
return (NULL);
/* NOTREACHED */
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)
#ifdef _REENTRANT
close(old->fd); /* don't allow a flush */
#else
close(fileno(old->fp)); /* don't allow a flush */
#endif
if (*xtype == 'r') {
(void)close(pdes[0]);
if (pdes[1] != STDOUT_FILENO) {
(void)dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
}
if (twoway)
(void)dup2(STDOUT_FILENO, STDIN_FILENO);
} else {
(void)close(pdes[1]);
if (pdes[0] != STDIN_FILENO) {
(void)dup2(pdes[0], STDIN_FILENO);
(void)close(pdes[0]);
}
}
execl(_PATH_BSHELL, "sh", "-c", command, NULL);
_exit(127);
/* NOTREACHED */
}
(void)__unlockenv();
/* Parent; assume fdopen can't fail. */
if (*xtype == 'r') {
iop = fdopen(pdes[0], xtype);
#ifdef _REENTRANT
cur->fd = pdes[0];
#endif
(void)close(pdes[1]);
} else {
iop = fdopen(pdes[1], xtype);
#ifdef _REENTRANT
cur->fd = pdes[1];
#endif
(void)close(pdes[0]);
}
/* Link into list of file descriptors. */
cur->fp = iop;
cur->pid = pid;
cur->next = pidlist;
pidlist = cur;
(void)rwlock_unlock(&pidlist_lock);
return (iop);
}
/*
* pclose --
* Pclose returns -1 if stream is not associated with a `popened' command,
* if already `pclosed', or waitpid returns an error.
*/
int
pclose(FILE *iop)
{
struct pid *cur, *last;
int pstat;
pid_t pid;
_DIAGASSERT(iop != NULL);
rwlock_wrlock(&pidlist_lock);
/* Find the appropriate file pointer. */
for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
if (cur->fp == iop)
break;
if (cur == NULL) {
(void)rwlock_unlock(&pidlist_lock);
return (-1);
}
(void)fclose(iop);
/* Remove the entry from the linked list. */
if (last == NULL)
pidlist = cur->next;
else
last->next = cur->next;
(void)rwlock_unlock(&pidlist_lock);
do {
pid = waitpid(cur->pid, &pstat, 0);
} while (pid == -1 && errno == EINTR);
free(cur);
return (pid == -1 ? -1 : pstat);
}
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