125 lines
2.5 KiB
C
Executable File
125 lines
2.5 KiB
C
Executable File
/* Copyright (c) 1988 AT&T */
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/* All Rights Reserved */
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/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */
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/* The copyright notice above does not evidence any */
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/* actual or intended publication of such source code. */
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#ident "@(#)popen.c 1.19 95/04/06 SMI" /* SVr4.0 1.29 */
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/*LINTLIBRARY*/
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#pragma weak pclose = _pclose
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#pragma weak popen = _popen
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#include "synonyms.h"
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#include "shlib.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include <thread.h>
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#include <synch.h>
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#include <mtlib.h>
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#define tst(a, b) (*mode == 'r'? (b) : (a))
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#define RDR 0
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#define WTR 1
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#define BIN_SH "/bin/sh"
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#define BIN_KSH "/bin/ksh"
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#define SH "sh"
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#define KSH "ksh"
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#define SHFLG "-c"
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extern int __xpg4; /* defined in _xpg4.c; 0 if not xpg4-compiled program */
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static int *popen_pid;
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#ifdef _REENTRANT
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static mutex_t popen_lock = DEFAULTMUTEX;
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#endif _REENTRANT
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FILE *
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popen(cmd, mode)
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const char *cmd, *mode;
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{
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int p[2];
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register int *poptr;
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register int myside, yourside, pid;
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if (popen_pid == NULL) {
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_mutex_lock(&popen_lock);
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if (popen_pid == NULL) {
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if ((popen_pid = (int *)calloc(256, sizeof (int)))
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== NULL) {
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_mutex_unlock(&popen_lock);
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return (NULL);
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}
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}
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_mutex_unlock(&popen_lock);
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}
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if (pipe(p) < 0)
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return (NULL);
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myside = tst(p[WTR], p[RDR]);
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yourside = tst(p[RDR], p[WTR]);
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if ((pid = vfork()) == 0) {
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/* myside and yourside reverse roles in child */
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int stdio;
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/* close all pipes from other popen's */
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for (poptr = popen_pid; poptr < popen_pid+256; poptr++) {
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if (*poptr)
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close(poptr - popen_pid);
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}
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stdio = tst(0, 1);
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(void) close(myside);
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if (yourside != stdio) {
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(void) close(stdio);
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(void) fcntl(yourside, F_DUPFD, stdio);
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(void) close(yourside);
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}
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if (__xpg4 == 0) { /* not XPG4 */
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if (access(BIN_SH, X_OK))
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_exit(127);
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(void) execl(BIN_SH, SH, SHFLG, cmd, (char *)0);
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} else {
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if (access(BIN_KSH, X_OK)) /* XPG4 Requirement */
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_exit(127);
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(void) execl(BIN_KSH, KSH, SHFLG, cmd, (char *)0);
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}
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_exit(1);
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}
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if (pid == -1)
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return (NULL);
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popen_pid[myside] = pid;
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(void) close(yourside);
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return (fdopen(myside, mode));
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}
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int
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pclose(ptr)
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FILE *ptr;
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{
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register int f;
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int status;
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if (!popen_pid)
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return (-1);
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f = fileno(ptr);
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(void) fclose(ptr);
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while (waitpid(popen_pid[f], &status, 0) < 0) {
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/* If waitpid fails with EINTR, restart the waitpid call */
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if (errno != EINTR) {
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status = -1;
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break;
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}
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}
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/* mark this pipe closed */
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popen_pid[f] = 0;
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return (status);
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}
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