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popen.c revision 1.4 
      1 /*
      2  * Copyright (c) 1988, 1993, 1994
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * This code is derived from software written by Ken Arnold and
      6  * published in UNIX Review, Vol. 6, No. 8.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  *
     36  */
     37 
     38 #ifndef lint
     39 static char sccsid[] = "@(#)popen.c	8.3 (Berkeley) 4/6/94";
     40 static char rcsid[] = "$Id: popen.c,v 1.4 1995/03/21 21:47:19 mycroft Exp $";
     41 #endif /* not lint */
     42 
     43 #include <sys/types.h>
     44 #include <sys/wait.h>
     45 
     46 #include <errno.h>
     47 #include <glob.h>
     48 #include <signal.h>
     49 #include <stdio.h>
     50 #include <stdlib.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 
     54 #include "extern.h"
     55 
     56 /*
     57  * Special version of popen which avoids call to shell.  This ensures noone
     58  * may create a pipe to a hidden program as a side effect of a list or dir
     59  * command.
     60  */
     61 static int *pids;
     62 static int fds;
     63 
     64 FILE *
     65 ftpd_popen(program, type)
     66 	char *program, *type;
     67 {
     68 	char *cp;
     69 	FILE *iop;
     70 	int argc, gargc, pdes[2], pid;
     71 	char **pop, *argv[100], *gargv[1000];
     72 
     73 	if (*type != 'r' && *type != 'w' || type[1])
     74 		return (NULL);
     75 
     76 	if (!pids) {
     77 		if ((fds = getdtablesize()) <= 0)
     78 			return (NULL);
     79 		if ((pids = (int *)malloc((u_int)(fds * sizeof(int)))) == NULL)
     80 			return (NULL);
     81 		memset(pids, 0, fds * sizeof(int));
     82 	}
     83 	if (pipe(pdes) < 0)
     84 		return (NULL);
     85 
     86 	/* break up string into pieces */
     87 	for (argc = 0, cp = program;; cp = NULL)
     88 		if (!(argv[argc++] = strtok(cp, " \t\n")))
     89 			break;
     90 
     91 	/* glob each piece */
     92 	gargv[0] = argv[0];
     93 	for (gargc = argc = 1; argv[argc]; argc++) {
     94 		glob_t gl;
     95 		int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE;
     96 
     97 		memset(&gl, 0, sizeof(gl));
     98 		if (glob(argv[argc], flags, NULL, &gl))
     99 			gargv[gargc++] = strdup(argv[argc]);
    100 		else
    101 			for (pop = gl.gl_pathv; *pop; pop++)
    102 				gargv[gargc++] = strdup(*pop);
    103 		globfree(&gl);
    104 	}
    105 	gargv[gargc] = NULL;
    106 
    107 	iop = NULL;
    108 	switch(pid = vfork()) {
    109 	case -1:			/* error */
    110 		(void)close(pdes[0]);
    111 		(void)close(pdes[1]);
    112 		goto pfree;
    113 		/* NOTREACHED */
    114 	case 0:				/* child */
    115 		if (*type == 'r') {
    116 			if (pdes[1] != STDOUT_FILENO) {
    117 				dup2(pdes[1], STDOUT_FILENO);
    118 				(void)close(pdes[1]);
    119 			}
    120 			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
    121 			(void)close(pdes[0]);
    122 		} else {
    123 			if (pdes[0] != STDIN_FILENO) {
    124 				dup2(pdes[0], STDIN_FILENO);
    125 				(void)close(pdes[0]);
    126 			}
    127 			(void)close(pdes[1]);
    128 		}
    129 		execv(gargv[0], gargv);
    130 		_exit(1);
    131 	}
    132 	/* parent; assume fdopen can't fail...  */
    133 	if (*type == 'r') {
    134 		iop = fdopen(pdes[0], type);
    135 		(void)close(pdes[1]);
    136 	} else {
    137 		iop = fdopen(pdes[1], type);
    138 		(void)close(pdes[0]);
    139 	}
    140 	pids[fileno(iop)] = pid;
    141 
    142 pfree:	for (argc = 1; gargv[argc] != NULL; argc++)
    143 		free(gargv[argc]);
    144 
    145 	return (iop);
    146 }
    147 
    148 int
    149 ftpd_pclose(iop)
    150 	FILE *iop;
    151 {
    152 	int fdes, omask, status;
    153 	pid_t pid;
    154 	sigset_t sigset, osigset;
    155 
    156 	/*
    157 	 * pclose returns -1 if stream is not associated with a
    158 	 * `popened' command, or, if already `pclosed'.
    159 	 */
    160 	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
    161 		return (-1);
    162 	(void)fclose(iop);
    163 	sigemptyset(&sigset);
    164 	sigaddset(&sigset, SIGINT);
    165 	sigaddset(&sigset, SIGQUIT);
    166 	sigaddset(&sigset, SIGHUP);
    167 	sigprocmask(SIG_BLOCK, &sigset, &osigset);
    168 	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
    169 		continue;
    170 	sigprocmask(SIG_SETMASK, &osigset, NULL);
    171 	pids[fdes] = 0;
    172 	if (pid < 0)
    173 		return (pid);
    174 	if (WIFEXITED(status))
    175 		return (WEXITSTATUS(status));
    176 	return (1);
    177 }
    178