text: /*	$OpenBSD: popen.c,v 1.24 2010/03/08 19:34:44 kettenis Exp $	*/
  /*	$NetBSD: popen.c,v 1.5 1995/04/11 02:45:00 cgd Exp $	*/
  
  /*
   * Copyright (c) 1988, 1993, 1994
   *	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. 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.
   *
   */
  
  #include <sys/types.h>
  #include <sys/wait.h>
  
  #include <errno.h>
  #include <glob.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <unistd.h>
  
  #include <netinet/in.h>
  
  #include "monitor.h"
  #include "extern.h"
  
  /*
   * Special version of popen which avoids call to shell.  This ensures noone
   * may create a pipe to a hidden program as a side effect of a list or dir
   * command.
   */
  static pid_t *pids;
  static int fds;
  
  #define MAX_ARGV	100
  #define MAX_GARGV	1000
  
  FILE *
  ftpd_popen(char *program, char *type)
  {
  	char *cp;
  	FILE *iop;
  	int argc, gargc, pdes[2];
  	pid_t pid;
  	char **pop, *argv[MAX_ARGV], *gargv[MAX_GARGV];
  
  	if ((*type != 'r' && *type != 'w') || type[1])
  		return (NULL);
  
  	if (!pids) {
  		if ((fds = getdtablesize()) <= 0)
  			return (NULL);
  		if ((pids = calloc(fds, sizeof(pid_t))) == NULL)
  			return (NULL);
  	}
  	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;
  
  	/* glob each piece */
  	gargv[0] = argv[0];
  	for (gargc = argc = 1; argv[argc]; argc++) {
  		glob_t gl;
  
  		memset(&gl, 0, sizeof(gl));
  		if (glob(argv[argc],
  		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
  		    NULL, &gl)) {
  			if (gargc < MAX_GARGV-1) {
  				gargv[gargc++] = strdup(argv[argc]);
  				if (gargv[gargc -1] == NULL)
  					fatal ("Out of memory.");
  			}
  
  		} else if (gl.gl_pathc > 0) {
  			for (pop = gl.gl_pathv; *pop && gargc < MAX_GARGV-1; pop++) {
  				gargv[gargc++] = strdup(*pop);
  				if (gargv[gargc - 1] == NULL)
  					fatal ("Out of memory.");
  			}
  		}
  		globfree(&gl);
  	}
  	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] != STDOUT_FILENO) {
  				dup2(pdes[1], STDOUT_FILENO);
  				(void)close(pdes[1]);
  			}
  			dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
  			(void)close(pdes[0]);
  		} else {
  			if (pdes[0] != STDIN_FILENO) {
  				dup2(pdes[0], STDIN_FILENO);
  				(void)close(pdes[0]);
  			}
  			(void)close(pdes[1]);
  		}
  		closelog();
  
  		if (strcmp(gargv[0], "/bin/ls") == 0) {
  			extern int optreset;
  			extern int ls_main(int, char **);
  
  			/* reset getopt for ls_main */
  			optreset = optind = 1;
  			exit(ls_main(gargc, gargv));
  		}
  
  		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; gargv[argc] != NULL; argc++)
  		free(gargv[argc]);
  
  	return (iop);
  }
  
  int
  ftpd_pclose(FILE *iop)
  {
  	int fdes, status;
  	pid_t pid;
  	sigset_t sigset, osigset;
  
  	/*
  	 * 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);
  	sigemptyset(&sigset);
  	sigaddset(&sigset, SIGINT);
  	sigaddset(&sigset, SIGQUIT);
  	sigaddset(&sigset, SIGHUP);
  	sigprocmask(SIG_BLOCK, &sigset, &osigset);
  	while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
  		continue;
  	sigprocmask(SIG_SETMASK, &osigset, NULL);
  	pids[fdes] = 0;
  	if (pid < 0)
  		return (-1);
  	if (WIFEXITED(status))
  		return (WEXITSTATUS(status));
  	return (1);
  }
  