popen.c   [plain text]

/*
 * Copyright (c) 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software written by Ken Arnold and
 * published in UNIX Review, Vol. 6, No. 8.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#ifndef lint
static char sccsid[] = "@(#)popen.c	5.9 (Berkeley) 2/25/91";
#endif /* not lint */

#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ftpd_var.h"

/*
 * Special version of popen which avoids call to shell.  This insures noone
 * may create a pipe to a hidden program as a side effect of a list or dir
 * command.
 */
static int *pids;
static int fds;

#define MAX_ARGV	100
#define MAX_GARGV	1000

FILE *
ftpd_popen(program, type)
	char *program, *type;
{
	register char *cp;
	FILE *volatile iop;
	int argc, gargc, pdes[2], pid;
	char **pop, *argv[MAX_ARGV], *gargv[MAX_GARGV], *vv[2];
	extern char **ftpglob(), **copyblk();
	extern void blkfree(char **);

	if ((*type != 'r' && *type != 'w') || type[1])
		return(NULL);

	if (!pids) {
		if ((fds = getdtablesize()) <= 0)
			return(NULL);
		if ((pids = (int *)malloc((u_int)(fds * sizeof(int)))) == NULL)
			return(NULL);
		memset((char *)pids, 0, fds * sizeof(int));
	}
	if (pipe(pdes) < 0)
		return(NULL);

	/* break up string into pieces */
	for (argc = 0, cp = program; argc < MAX_ARGV - 1; cp = NULL)
		if (!(argv[argc++] = strtok(cp, " \t\n")))
			break;
	argv[MAX_ARGV-1] = NULL;
	for (argc = 0; argv[argc]; argc++)
		argv[argc] = strdup(argv[argc]);

	/* glob each piece */
	gargv[0] = argv[0];
	for (gargc = argc = 1; argv[argc]; argc++) {
		if (!(pop = ftpglob(argv[argc]))) {	/* globbing failed */
			vv[0] = argv[argc];
			vv[1] = NULL;
			pop = copyblk(vv);
		}
		argv[argc] = (char *)pop;		/* save to free later */
		while (*pop && gargc < MAX_GARGV)
			gargv[gargc++] = *pop++;
	}
	gargv[gargc] = NULL;

	iop = NULL;
	switch(pid = fork()) {
	case -1:			/* error */
		(void)close(pdes[0]);
		(void)close(pdes[1]);
		goto pfree;
		/* NOTREACHED */
	case 0:				/* child */
		if (*type == 'r') {
			if (pdes[1] != 1) {
				dup2(pdes[1], 1);
				dup2(pdes[1], 2);	/* stderr, too! */
				(void)close(pdes[1]);
			}
			(void)close(pdes[0]);
		} else {
			if (pdes[0] != 0) {
				dup2(pdes[0], 0);
				(void)close(pdes[0]);
			}
			(void)close(pdes[1]);
		}
		execv(gargv[0], gargv);
		_exit(1);
	}
	/* parent; assume fdopen can't fail...  */
	if (*type == 'r') {
		iop = fdopen(pdes[0], type);
		(void)close(pdes[1]);
	} else {
		iop = fdopen(pdes[1], type);
		(void)close(pdes[0]);
	}
	pids[fileno(iop)] = pid;

pfree:	for (argc = 1; argv[argc] != NULL; argc++) {
		blkfree((char **)argv[argc]);
		free((char *)argv[argc]);
	}
	return(iop);
}

int
ftpd_pclose(iop)
	FILE *iop;
{
	register int fdes;
#ifdef USE_SIGPROCMASK
	sigset_t old, new;
#else
	int omask;
#endif
#ifdef WAIT_USES_INT
	int stat_loc;
#else
	union wait stat_loc;
#endif
	int pid;

	/*
	 * pclose returns -1 if stream is not associated with a
	 * `popened' command, or, if already `pclosed'.
	 */
	if (pids == 0 || pids[fdes = fileno(iop)] == 0)
		return(-1);
	(void)fclose(iop);
#ifdef USE_SIGPROCMASK
	sigemptyset(&old);
	sigemptyset(&new);
	sigaddset(&new,SIGINT);
	sigaddset(&new,SIGQUIT);
	sigaddset(&new,SIGHUP);
	sigprocmask(SIG_BLOCK, &new, &old);
	while ((pid = wait((int *)&stat_loc)) != pids[fdes] && pid != -1);
	sigprocmask(SIG_SETMASK, &old, NULL);
#else
	omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
	while ((pid = wait((int *)&stat_loc)) != pids[fdes] && pid != -1);
	sigsetmask(omask);
#endif
	pids[fdes] = 0;
#ifdef WAIT_USES_INT
	return(pid == -1 ? -1 : stat_loc);
#else
	return(pid == -1 ? -1 : stat_loc.w_status);
#endif
}