popen.c revision 23734
11573Srgrimes/* 21573Srgrimes * Copyright (c) 1988, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software written by Ken Arnold and 61573Srgrimes * published in UNIX Review, Vol. 6, No. 8. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 3. All advertising materials mentioning features or use of this software 171573Srgrimes * must display the following acknowledgement: 181573Srgrimes * This product includes software developed by the University of 191573Srgrimes * California, Berkeley and its contributors. 201573Srgrimes * 4. Neither the name of the University nor the names of its contributors 211573Srgrimes * may be used to endorse or promote products derived from this software 221573Srgrimes * without specific prior written permission. 231573Srgrimes * 241573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341573Srgrimes * SUCH DAMAGE. 351573Srgrimes */ 361573Srgrimes 371573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 3823668Speterstatic char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95"; 391573Srgrimes#endif /* LIBC_SCCS and not lint */ 401573Srgrimes 411573Srgrimes#include <sys/param.h> 421573Srgrimes#include <sys/wait.h> 431573Srgrimes 441573Srgrimes#include <signal.h> 451573Srgrimes#include <errno.h> 461573Srgrimes#include <unistd.h> 471573Srgrimes#include <stdio.h> 481573Srgrimes#include <stdlib.h> 491573Srgrimes#include <string.h> 501573Srgrimes#include <paths.h> 511573Srgrimes 521573Srgrimesstatic struct pid { 531573Srgrimes struct pid *next; 541573Srgrimes FILE *fp; 551573Srgrimes pid_t pid; 568870Srgrimes} *pidlist; 578870Srgrimes 581573SrgrimesFILE * 5923668Speterpopen(command, type) 6023668Speter const char *command, *type; 611573Srgrimes{ 621573Srgrimes struct pid *cur; 631573Srgrimes FILE *iop; 6423668Speter int pdes[2], pid, twoway; 651573Srgrimes 6623668Speter /* 6723668Speter * Lite2 introduced two-way popen() pipes using socketpair(). 6823668Speter * FreeBSD's pipe() is bidirectional, so we use that. 6923668Speter */ 7023668Speter if (strchr(type, '+')) { 7123668Speter twoway = 1; 7223668Speter type = "r+"; 7323668Speter } else { 7423668Speter twoway = 0; 7523734Sbde if ((*type != 'r' && *type != 'w') || type[1]) 7623668Speter return (NULL); 7723668Speter } 7823668Speter if (pipe(pdes) < 0) 791573Srgrimes return (NULL); 801573Srgrimes 8123734Sbde if ((cur = malloc(sizeof(struct pid))) == NULL) { 8223734Sbde (void)close(pdes[0]); 8323734Sbde (void)close(pdes[1]); 841573Srgrimes return (NULL); 8523734Sbde } 861573Srgrimes 871573Srgrimes switch (pid = vfork()) { 881573Srgrimes case -1: /* Error. */ 891573Srgrimes (void)close(pdes[0]); 901573Srgrimes (void)close(pdes[1]); 919272Shsu free(cur); 921573Srgrimes return (NULL); 931573Srgrimes /* NOTREACHED */ 941573Srgrimes case 0: /* Child. */ 951573Srgrimes if (*type == 'r') { 961573Srgrimes if (pdes[1] != STDOUT_FILENO) { 971573Srgrimes (void)dup2(pdes[1], STDOUT_FILENO); 981573Srgrimes (void)close(pdes[1]); 9923668Speter pdes[1] = STDOUT_FILENO; 1001573Srgrimes } 1011573Srgrimes (void) close(pdes[0]); 10223668Speter if (twoway && (pdes[1] != STDIN_FILENO)) 10323668Speter (void)dup2(pdes[1], STDIN_FILENO); 1041573Srgrimes } else { 1051573Srgrimes if (pdes[0] != STDIN_FILENO) { 1061573Srgrimes (void)dup2(pdes[0], STDIN_FILENO); 1071573Srgrimes (void)close(pdes[0]); 1081573Srgrimes } 1091573Srgrimes (void)close(pdes[1]); 1101573Srgrimes } 11123668Speter execl(_PATH_BSHELL, "sh", "-c", command, NULL); 1121573Srgrimes _exit(127); 1131573Srgrimes /* NOTREACHED */ 1141573Srgrimes } 1151573Srgrimes 1161573Srgrimes /* Parent; assume fdopen can't fail. */ 1171573Srgrimes if (*type == 'r') { 1181573Srgrimes iop = fdopen(pdes[0], type); 1191573Srgrimes (void)close(pdes[1]); 1201573Srgrimes } else { 1211573Srgrimes iop = fdopen(pdes[1], type); 1221573Srgrimes (void)close(pdes[0]); 1231573Srgrimes } 1241573Srgrimes 1251573Srgrimes /* Link into list of file descriptors. */ 1261573Srgrimes cur->fp = iop; 1271573Srgrimes cur->pid = pid; 1281573Srgrimes cur->next = pidlist; 1291573Srgrimes pidlist = cur; 1301573Srgrimes 1311573Srgrimes return (iop); 1321573Srgrimes} 1331573Srgrimes 1341573Srgrimes/* 1351573Srgrimes * pclose -- 1361573Srgrimes * Pclose returns -1 if stream is not associated with a `popened' command, 1371573Srgrimes * if already `pclosed', or waitpid returns an error. 1381573Srgrimes */ 1391573Srgrimesint 1401573Srgrimespclose(iop) 1411573Srgrimes FILE *iop; 1421573Srgrimes{ 1431573Srgrimes register struct pid *cur, *last; 1441573Srgrimes int omask; 14523668Speter int pstat; 1461573Srgrimes pid_t pid; 1471573Srgrimes 1481573Srgrimes /* Find the appropriate file pointer. */ 1491573Srgrimes for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 1501573Srgrimes if (cur->fp == iop) 1511573Srgrimes break; 1521573Srgrimes if (cur == NULL) 1531573Srgrimes return (-1); 1541573Srgrimes 15523668Speter (void)fclose(iop); 15623668Speter 1571573Srgrimes do { 15823668Speter pid = waitpid(cur->pid, &pstat, 0); 1591573Srgrimes } while (pid == -1 && errno == EINTR); 1601573Srgrimes 1611573Srgrimes /* Remove the entry from the linked list. */ 1621573Srgrimes if (last == NULL) 1631573Srgrimes pidlist = cur->next; 1641573Srgrimes else 1651573Srgrimes last->next = cur->next; 1661573Srgrimes free(cur); 1678870Srgrimes 16823668Speter return (pid == -1 ? -1 : pstat); 1691573Srgrimes} 170