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ttyaction.c revision 1.18 
      1 /*	$NetBSD: ttyaction.c,v 1.18 2005/08/27 17:06:29 elad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1996 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Gordon W. Ross.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * For each matching "tty" and "action" run the "command."
     41  * See fnmatch() for matching the tty name.
     42  */
     43 
     44 #include <sys/cdefs.h>
     45 #if defined(LIBC_SCCS) && !defined(lint)
     46 __RCSID("$NetBSD: ttyaction.c,v 1.18 2005/08/27 17:06:29 elad Exp $");
     47 #endif /* LIBC_SCCS and not lint */
     48 
     49 #include <sys/types.h>
     50 #include <sys/wait.h>
     51 
     52 #include <assert.h>
     53 #include <err.h>
     54 #include <errno.h>
     55 #include <fcntl.h>
     56 #include <fnmatch.h>
     57 #include <paths.h>
     58 #include <stdio.h>
     59 #include <stdlib.h>
     60 #include <string.h>
     61 #include <unistd.h>
     62 
     63 #include "util.h"
     64 
     65 #ifndef _PATH_TTYACTION
     66 #define _PATH_TTYACTION "/etc/ttyaction"
     67 #endif
     68 
     69 static const char *actfile = _PATH_TTYACTION;
     70 static const char *pathenv = "PATH=" _PATH_STDPATH;
     71 
     72 int
     73 ttyaction(const char *tty, const char *act, const char *user)
     74 {
     75 	FILE *fp;
     76 	char *p1, *p2;
     77 	const char *argv[4];
     78 	const char *envp[8];
     79 	char *lastp;
     80 	char line[1024];
     81 	char env_tty[64];
     82 	char env_act[64];
     83 	char env_user[256];
     84 	int error, linenum, status;
     85 	pid_t pid;
     86 
     87 	_DIAGASSERT(tty != NULL);
     88 	_DIAGASSERT(act != NULL);
     89 	_DIAGASSERT(user != NULL);
     90 
     91 	fp = fopen(actfile, "r");
     92 	if (fp == NULL)
     93 		return 0;
     94 
     95 	/* Skip the "/dev/" part of the first arg. */
     96 	if (!strncmp(tty, "/dev/", (size_t)5))
     97 		tty += 5;
     98 
     99 	/* Args will be: "sh -c ..." */
    100 	argv[0] = _PATH_BSHELL;
    101 	argv[1] = "-c";
    102 	argv[2] = NULL;	/* see below */
    103 	argv[3] = NULL;
    104 
    105 	/*
    106 	 * Environment needs: TTY, ACT, USER
    107 	 */
    108 	snprintf(env_tty, sizeof(env_tty), "TTY=%s", tty);
    109 	snprintf(env_act, sizeof(env_act), "ACT=%s", act);
    110 	snprintf(env_user, sizeof(env_user), "USER=%s", user);
    111 	envp[0] = pathenv;
    112 	envp[1] = env_tty;
    113 	envp[2] = env_act;
    114 	envp[3] = env_user;
    115 	envp[4] = NULL;
    116 
    117 	linenum = 0;
    118 	status = 0;
    119 	while (fgets(line, (int)sizeof(line), fp)) {
    120 		linenum++;
    121 
    122 		/* Allow comment lines. */
    123 		if (line[0] == '#')
    124 			continue;
    125 
    126 		p1 = strtok_r(line, " \t", &lastp);
    127 		p2 = strtok_r(NULL, " \t", &lastp);
    128 		/* This arg goes to end of line. */
    129 		argv[2] = strtok_r(NULL, "\n", &lastp);
    130 		if (!p1 || !p2 || !argv[2]) {
    131 			warnx("%s: line %d format error", actfile, linenum);
    132 			continue;
    133 		}
    134 		if (fnmatch(p1, tty, 0) || fnmatch(p2, act, 0))
    135 			continue;
    136 		/* OK, this is a match.  Run the command. */
    137 		pid = fork();
    138 		if (pid == -1) {
    139 			warnx("fork failed: %s", strerror(errno));
    140 			continue;
    141 		}
    142 		if (pid == 0) {
    143 			/* This is the child. */
    144 			error = execve(argv[0],
    145 			    (char *const *)__UNCONST(argv),
    146 			    (char *const *)__UNCONST(envp));
    147 			/* If we get here, it is an error. */
    148 			warnx("%s: line %d: exec failed: %s",
    149 				  actfile, linenum, strerror(errno));
    150 			_exit(1);
    151 		}
    152 		/* This is the parent. */
    153 		error = waitpid(pid, &status, 0);
    154 		if (error == -1) {
    155 			warnx("%s: line %d: wait failed: %s",
    156 				  actfile, linenum, strerror(errno));
    157 			continue;
    158 		}
    159 		if (WTERMSIG(status)) {
    160 			warnx("%s: line %d: child died with signal %d",
    161 				  actfile, linenum, WTERMSIG(status));
    162 			continue;
    163 		}
    164 	}
    165 	fclose(fp);
    166 	return status;
    167 }
    168