Initial Contribution
This commit is contained in:
The Android Open Source Project
167
libc/unistd/popen.c
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167
libc/unistd/popen.c
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/* $OpenBSD: popen.c,v 1.17 2005/08/08 08:05:34 espie Exp $ */
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/*
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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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* 3. 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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#include <sys/param.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 <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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static struct pid {
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struct pid *next;
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FILE *fp;
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pid_t pid;
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} *pidlist;
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FILE *
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popen(const char *program, const char *type)
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{
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struct pid * volatile cur;
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FILE *iop;
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int pdes[2];
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pid_t pid;
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if ((*type != 'r' && *type != 'w') || type[1] != '\0') {
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errno = EINVAL;
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return (NULL);
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}
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if ((cur = malloc(sizeof(struct pid))) == NULL)
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return (NULL);
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if (pipe(pdes) < 0) {
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free(cur);
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return (NULL);
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}
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switch (pid = vfork()) {
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case -1: /* Error. */
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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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/* NOTREACHED */
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case 0: /* Child. */
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{
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struct pid *pcur;
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/*
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* because vfork() instead of fork(), must leak FILE *,
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* but luckily we are terminally headed for an execl()
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*/
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for (pcur = pidlist; pcur; pcur = pcur->next)
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close(fileno(pcur->fp));
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if (*type == 'r') {
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int tpdes1 = pdes[1];
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(void) close(pdes[0]);
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/*
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* We must NOT modify pdes, due to the
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* semantics of vfork.
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*/
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if (tpdes1 != STDOUT_FILENO) {
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(void)dup2(tpdes1, STDOUT_FILENO);
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(void)close(tpdes1);
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tpdes1 = STDOUT_FILENO;
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}
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} else {
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(void)close(pdes[1]);
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if (pdes[0] != STDIN_FILENO) {
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(void)dup2(pdes[0], STDIN_FILENO);
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(void)close(pdes[0]);
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}
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}
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execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL);
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_exit(127);
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/* NOTREACHED */
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}
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}
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/* Parent; assume fdopen can't fail. */
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if (*type == 'r') {
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iop = fdopen(pdes[0], type);
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(void)close(pdes[1]);
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} else {
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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. */
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cur->fp = iop;
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cur->pid = pid;
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cur->next = pidlist;
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pidlist = cur;
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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;
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int pstat;
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pid_t pid;
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/* Find the appropriate file pointer. */
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for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
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if (cur->fp == iop)
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break;
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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. */
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if (last == NULL)
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pidlist = cur->next;
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else
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last->next = cur->next;
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free(cur);
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return (pid == -1 ? -1 : pstat);
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}
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