3945141fa2
Move fdopen() up near other resource allocation like malloc(); do proper deallocation on failure later on in the function. Submitted by: Ramachandra Topannavar <rtopannavar@panasas.com> Reviewed by: jilles Approved by: jhb (mentor) MFC after: 2 weeks Sponsored by: Panasas, Inc. Differential Revision: https://reviews.freebsd.org/D4126 M lib/libc/gen/popen.c
230 lines
6.0 KiB
C
230 lines
6.0 KiB
C
/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software written by Ken Arnold and
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* published in UNIX Review, Vol. 6, No. 8.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <paths.h>
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#include <pthread.h>
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#include "un-namespace.h"
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#include "libc_private.h"
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extern char **environ;
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struct pid {
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SLIST_ENTRY(pid) next;
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FILE *fp;
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pid_t pid;
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};
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static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
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static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
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#define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
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#define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex)
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FILE *
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popen(const char *command, const char *type)
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{
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struct pid *cur;
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FILE *iop;
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int pdes[2], pid, twoway, cloexec;
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int pdes_unused_in_parent;
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char *argv[4];
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struct pid *p;
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cloexec = strchr(type, 'e') != NULL;
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/*
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* Lite2 introduced two-way popen() pipes using _socketpair().
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* FreeBSD's pipe() is bidirectional, so we use that.
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*/
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if (strchr(type, '+')) {
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twoway = 1;
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type = "r+";
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} else {
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twoway = 0;
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if ((*type != 'r' && *type != 'w') ||
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(type[1] && (type[1] != 'e' || type[2])))
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return (NULL);
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}
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if (pipe2(pdes, O_CLOEXEC) < 0)
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return (NULL);
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if ((cur = malloc(sizeof(struct pid))) == NULL) {
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(void)_close(pdes[0]);
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(void)_close(pdes[1]);
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return (NULL);
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}
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if (*type == 'r') {
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iop = fdopen(pdes[0], type);
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pdes_unused_in_parent = pdes[1];
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} else {
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iop = fdopen(pdes[1], type);
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pdes_unused_in_parent = pdes[0];
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}
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if (iop == NULL) {
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(void)_close(pdes[0]);
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(void)_close(pdes[1]);
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free(cur);
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return (NULL);
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}
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argv[0] = "sh";
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argv[1] = "-c";
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argv[2] = (char *)command;
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argv[3] = NULL;
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THREAD_LOCK();
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switch (pid = vfork()) {
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case -1: /* Error. */
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THREAD_UNLOCK();
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/*
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* The _close() closes the unused end of pdes[], while
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* the fclose() closes the used end of pdes[], *and* cleans
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* up iop.
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*/
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(void)_close(pdes_unused_in_parent);
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free(cur);
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(void)fclose(iop);
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return (NULL);
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/* NOTREACHED */
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case 0: /* Child. */
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if (*type == 'r') {
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/*
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* The _dup2() to STDIN_FILENO is repeated to avoid
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* writing to pdes[1], which might corrupt the
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* parent's copy. This isn't good enough in
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* general, since the _exit() is no return, so
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* the compiler is free to corrupt all the local
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* variables.
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*/
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if (pdes[1] != STDOUT_FILENO) {
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(void)_dup2(pdes[1], STDOUT_FILENO);
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if (twoway)
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(void)_dup2(STDOUT_FILENO, STDIN_FILENO);
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} else if (twoway && (pdes[1] != STDIN_FILENO)) {
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(void)_dup2(pdes[1], STDIN_FILENO);
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(void)_fcntl(pdes[1], F_SETFD, 0);
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} else
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(void)_fcntl(pdes[1], F_SETFD, 0);
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} else {
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if (pdes[0] != STDIN_FILENO) {
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(void)_dup2(pdes[0], STDIN_FILENO);
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} else
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(void)_fcntl(pdes[0], F_SETFD, 0);
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}
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SLIST_FOREACH(p, &pidlist, next)
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(void)_close(fileno(p->fp));
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_execve(_PATH_BSHELL, argv, environ);
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_exit(127);
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/* NOTREACHED */
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}
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THREAD_UNLOCK();
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/* Parent. */
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(void)_close(pdes_unused_in_parent);
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/* Link into list of file descriptors. */
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cur->fp = iop;
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cur->pid = pid;
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THREAD_LOCK();
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SLIST_INSERT_HEAD(&pidlist, cur, next);
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THREAD_UNLOCK();
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/*
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* To guard against undesired fd passing with concurrent calls,
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* only clear the close-on-exec flag after linking the file into
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* the list which will cause an explicit close.
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*/
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if (!cloexec)
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(void)_fcntl(*type == 'r' ? pdes[0] : pdes[1], F_SETFD, 0);
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return (iop);
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}
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/*
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* pclose --
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* Pclose returns -1 if stream is not associated with a `popened' command,
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* if already `pclosed', or waitpid returns an error.
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*/
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int
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pclose(FILE *iop)
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{
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struct pid *cur, *last = NULL;
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int pstat;
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pid_t pid;
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/*
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* Find the appropriate file pointer and remove it from the list.
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*/
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THREAD_LOCK();
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SLIST_FOREACH(cur, &pidlist, next) {
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if (cur->fp == iop)
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break;
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last = cur;
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}
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if (cur == NULL) {
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THREAD_UNLOCK();
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return (-1);
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}
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if (last == NULL)
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SLIST_REMOVE_HEAD(&pidlist, next);
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else
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SLIST_REMOVE_AFTER(last, next);
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THREAD_UNLOCK();
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(void)fclose(iop);
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do {
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pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
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} while (pid == -1 && errno == EINTR);
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free(cur);
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return (pid == -1 ? -1 : pstat);
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}
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