/* Copyright (C) 2004 Manuel Novoa III
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/* Copyright (C) 2004 Manuel Novoa III
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*
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*
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* This library is free software; you can redistribute it and/or
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* version 2 of the License, or (at your option) any later version.
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*
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*
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* This library is distributed in the hope that it will be useful,
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* Library General Public License for more details.
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*
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*
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* You should have received a copy of the GNU Library General Public
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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*/
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/* Jan 1, 2004
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/* Jan 1, 2004
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*
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*
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* Rewrite popen for SUSv3 compliance.
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* Rewrite popen for SUSv3 compliance.
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* Added a list of popen()'d to store pids and use waitpid() in pclose().
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* Added a list of popen()'d to store pids and use waitpid() in pclose().
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* Loop on waitpid() failure due to EINTR as required.
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* Loop on waitpid() failure due to EINTR as required.
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* Close parent's popen()'d FILEs in the {v}fork()'d child.
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* Close parent's popen()'d FILEs in the {v}fork()'d child.
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* Fix failure exit code for failed execve().
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* Fix failure exit code for failed execve().
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*/
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*/
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#include <stdio.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <errno.h>
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#include <unistd.h>
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#include <unistd.h>
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#include <sys/wait.h>
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#include <sys/wait.h>
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/* uClinux-2.0 has vfork, but Linux 2.0 doesn't */
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/* uClinux-2.0 has vfork, but Linux 2.0 doesn't */
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#include <sys/syscall.h>
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#include <sys/syscall.h>
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#if ! defined __NR_vfork
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#if ! defined __NR_vfork
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# define vfork fork
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# define vfork fork
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# define VFORK_LOCK ((void) 0)
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# define VFORK_LOCK ((void) 0)
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# define VFORK_UNLOCK ((void) 0)
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# define VFORK_UNLOCK ((void) 0)
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#endif
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#endif
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#ifdef __UCLIBC_HAS_THREADS__
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#ifdef __UCLIBC_HAS_THREADS__
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#include <pthread.h>
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#include <pthread.h>
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static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
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static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
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# define LOCK __pthread_mutex_lock(&mylock)
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# define LOCK __pthread_mutex_lock(&mylock)
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# define UNLOCK __pthread_mutex_unlock(&mylock);
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# define UNLOCK __pthread_mutex_unlock(&mylock);
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#else
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#else
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# define LOCK ((void) 0)
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# define LOCK ((void) 0)
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# define UNLOCK ((void) 0)
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# define UNLOCK ((void) 0)
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#endif
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#endif
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#ifndef VFORK_LOCK
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#ifndef VFORK_LOCK
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# define VFORK_LOCK LOCK
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# define VFORK_LOCK LOCK
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# define VFORK_UNLOCK UNLOCK
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# define VFORK_UNLOCK UNLOCK
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#endif
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#endif
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/* Temporarily support old stdio code. */
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/* Temporarily support old stdio code. */
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#ifndef __MASK_READING
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#ifndef __MASK_READING
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#define __filedes filedes
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#define __filedes filedes
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#endif
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#endif
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struct popen_list_item {
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struct popen_list_item {
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struct popen_list_item *next;
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struct popen_list_item *next;
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FILE *f;
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FILE *f;
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pid_t pid;
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pid_t pid;
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};
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};
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static struct popen_list_item *popen_list /* = NULL (bss initialized) */;
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static struct popen_list_item *popen_list /* = NULL (bss initialized) */;
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FILE *popen(const char *command, const char *modes)
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FILE *popen(const char *command, const char *modes)
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{
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{
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FILE *fp;
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FILE *fp;
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struct popen_list_item *pi;
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struct popen_list_item *pi;
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struct popen_list_item *po;
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struct popen_list_item *po;
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int pipe_fd[2];
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int pipe_fd[2];
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int parent_fd;
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int parent_fd;
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int child_fd;
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int child_fd;
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int child_writing; /* Doubles as the desired child fildes. */
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int child_writing; /* Doubles as the desired child fildes. */
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pid_t pid;
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pid_t pid;
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child_writing = 0; /* Assume child is writing. */
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child_writing = 0; /* Assume child is writing. */
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if (modes[0] != 'w') { /* Parent not writing... */
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if (modes[0] != 'w') { /* Parent not writing... */
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++child_writing; /* so child must be writing. */
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++child_writing; /* so child must be writing. */
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if (modes[0] != 'r') { /* Oops! Parent not reading either! */
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if (modes[0] != 'r') { /* Oops! Parent not reading either! */
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__set_errno(EINVAL);
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__set_errno(EINVAL);
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goto RET_NULL;
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goto RET_NULL;
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}
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}
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}
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}
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if (!(pi = malloc(sizeof(struct popen_list_item)))) {
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if (!(pi = malloc(sizeof(struct popen_list_item)))) {
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goto RET_NULL;
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goto RET_NULL;
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}
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}
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if (pipe(pipe_fd)) {
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if (pipe(pipe_fd)) {
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goto FREE_PI;
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goto FREE_PI;
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}
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}
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child_fd = pipe_fd[child_writing];
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child_fd = pipe_fd[child_writing];
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parent_fd = pipe_fd[1-child_writing];
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parent_fd = pipe_fd[1-child_writing];
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if (!(fp = fdopen(parent_fd, modes))) {
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if (!(fp = fdopen(parent_fd, modes))) {
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close(parent_fd);
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close(parent_fd);
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close(child_fd);
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close(child_fd);
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goto FREE_PI;
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goto FREE_PI;
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}
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}
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VFORK_LOCK;
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VFORK_LOCK;
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if ((pid = vfork()) == 0) { /* Child of vfork... */
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if ((pid = vfork()) == 0) { /* Child of vfork... */
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close(parent_fd);
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close(parent_fd);
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if (child_fd != child_writing) {
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if (child_fd != child_writing) {
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dup2(child_fd, child_writing);
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dup2(child_fd, child_writing);
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close(child_fd);
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close(child_fd);
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}
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}
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/* SUSv3 requires that any previously popen()'d streams in the
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/* SUSv3 requires that any previously popen()'d streams in the
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* parent shall be closed in the child. */
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* parent shall be closed in the child. */
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for (po = popen_list ; po ; po = po->next) {
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for (po = popen_list ; po ; po = po->next) {
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close(po->f->__filedes);
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close(po->f->__filedes);
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}
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}
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execl("/bin/sh", "sh", "-c", command, (char *)0);
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execl("/bin/sh", "sh", "-c", command, (char *)0);
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/* SUSv3 mandates an exit code of 127 for the child if the
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/* SUSv3 mandates an exit code of 127 for the child if the
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* command interpreter can not be invoked. */
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* command interpreter can not be invoked. */
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_exit(127);
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_exit(127);
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}
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}
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VFORK_UNLOCK;
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VFORK_UNLOCK;
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/* We need to close the child filedes whether vfork failed or
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/* We need to close the child filedes whether vfork failed or
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* it succeeded and we're in the parent. */
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* it succeeded and we're in the parent. */
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close(child_fd);
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close(child_fd);
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if (pid > 0) { /* Parent of vfork... */
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if (pid > 0) { /* Parent of vfork... */
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pi->pid = pid;
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pi->pid = pid;
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pi->f = fp;
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pi->f = fp;
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LOCK;
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LOCK;
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pi->next = popen_list;
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pi->next = popen_list;
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popen_list = pi;
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popen_list = pi;
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UNLOCK;
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UNLOCK;
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return fp;
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return fp;
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}
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}
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/* If we get here, vfork failed. */
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/* If we get here, vfork failed. */
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fclose(fp); /* Will close parent_fd. */
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fclose(fp); /* Will close parent_fd. */
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FREE_PI:
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FREE_PI:
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free(pi);
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free(pi);
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RET_NULL:
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RET_NULL:
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return NULL;
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return NULL;
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}
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}
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int pclose(FILE *stream)
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int pclose(FILE *stream)
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{
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{
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struct popen_list_item *p;
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struct popen_list_item *p;
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int stat;
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int stat;
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pid_t pid;
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pid_t pid;
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/* First, find the list entry corresponding to stream and remove it
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/* First, find the list entry corresponding to stream and remove it
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* from the list. Set p to the list item (NULL if not found). */
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* from the list. Set p to the list item (NULL if not found). */
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LOCK;
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LOCK;
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if ((p = popen_list) != NULL) {
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if ((p = popen_list) != NULL) {
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if (p->f == stream) {
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if (p->f == stream) {
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popen_list = p->next;
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popen_list = p->next;
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} else {
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} else {
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struct popen_list_item *t;
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struct popen_list_item *t;
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do {
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do {
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t = p;
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t = p;
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if (!(p = t->next)) {
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if (!(p = t->next)) {
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__set_errno(EINVAL); /* Not required by SUSv3. */
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__set_errno(EINVAL); /* Not required by SUSv3. */
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break;
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break;
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}
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}
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if (p->f == stream) {
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if (p->f == stream) {
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t->next = p->next;
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t->next = p->next;
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break;
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break;
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}
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}
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} while (1);
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} while (1);
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}
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}
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}
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}
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UNLOCK;
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UNLOCK;
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if (p) {
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if (p) {
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pid = p->pid; /* Save the pid we need */
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pid = p->pid; /* Save the pid we need */
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free(p); /* and free the list item. */
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free(p); /* and free the list item. */
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fclose(stream); /* The SUSv3 example code ignores the return. */
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fclose(stream); /* The SUSv3 example code ignores the return. */
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/* SUSv3 specificly requires that pclose not return before the child
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/* SUSv3 specificly requires that pclose not return before the child
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* terminates, in order to disallow pclose from returning on EINTR. */
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* terminates, in order to disallow pclose from returning on EINTR. */
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do {
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do {
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if (waitpid(pid, &stat, 0) >= 0) {
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if (waitpid(pid, &stat, 0) >= 0) {
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return stat;
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return stat;
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}
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}
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if (errno != EINTR) {
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if (errno != EINTR) {
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break;
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break;
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}
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}
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} while (1);
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} while (1);
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}
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}
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return -1;
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return -1;
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}
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}
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