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      1 /*	$NetBSD: ttyaction.c,v 1.19 2008/04/28 20:23:03 martin 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * For each matching "tty" and "action" run the "command."
     34  * See fnmatch() for matching the tty name.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 #if defined(LIBC_SCCS) && !defined(lint)
     39 __RCSID("$NetBSD: ttyaction.c,v 1.19 2008/04/28 20:23:03 martin Exp $");
     40 #endif /* LIBC_SCCS and not lint */
     41 
     42 #include <sys/types.h>
     43 #include <sys/wait.h>
     44 
     45 #include <assert.h>
     46 #include <err.h>
     47 #include <errno.h>
     48 #include <fcntl.h>
     49 #include <fnmatch.h>
     50 #include <paths.h>
     51 #include <stdio.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 #include <unistd.h>
     55 
     56 #include "util.h"
     57 
     58 #ifndef _PATH_TTYACTION
     59 #define _PATH_TTYACTION "/etc/ttyaction"
     60 #endif
     61 
     62 static const char *actfile = _PATH_TTYACTION;
     63 static const char *pathenv = "PATH=" _PATH_STDPATH;
     64 
     65 int
     66 ttyaction(const char *tty, const char *act, const char *user)
     67 {
     68 	FILE *fp;
     69 	char *p1, *p2;
     70 	const char *argv[4];
     71 	const char *envp[8];
     72 	char *lastp;
     73 	char line[1024];
     74 	char env_tty[64];
     75 	char env_act[64];
     76 	char env_user[256];
     77 	int error, linenum, status;
     78 	pid_t pid;
     79 
     80 	_DIAGASSERT(tty != NULL);
     81 	_DIAGASSERT(act != NULL);
     82 	_DIAGASSERT(user != NULL);
     83 
     84 	fp = fopen(actfile, "r");
     85 	if (fp == NULL)
     86 		return 0;
     87 
     88 	/* Skip the "/dev/" part of the first arg. */
     89 	if (!strncmp(tty, "/dev/", (size_t)5))
     90 		tty += 5;
     91 
     92 	/* Args will be: "sh -c ..." */
     93 	argv[0] = _PATH_BSHELL;
     94 	argv[1] = "-c";
     95 	argv[2] = NULL;	/* see below */
     96 	argv[3] = NULL;
     97 
     98 	/*
     99 	 * Environment needs: TTY, ACT, USER
    100 	 */
    101 	snprintf(env_tty, sizeof(env_tty), "TTY=%s", tty);
    102 	snprintf(env_act, sizeof(env_act), "ACT=%s", act);
    103 	snprintf(env_user, sizeof(env_user), "USER=%s", user);
    104 	envp[0] = pathenv;
    105 	envp[1] = env_tty;
    106 	envp[2] = env_act;
    107 	envp[3] = env_user;
    108 	envp[4] = NULL;
    109 
    110 	linenum = 0;
    111 	status = 0;
    112 	while (fgets(line, (int)sizeof(line), fp)) {
    113 		linenum++;
    114 
    115 		/* Allow comment lines. */
    116 		if (line[0] == '#')
    117 			continue;
    118 
    119 		p1 = strtok_r(line, " \t", &lastp);
    120 		p2 = strtok_r(NULL, " \t", &lastp);
    121 		/* This arg goes to end of line. */
    122 		argv[2] = strtok_r(NULL, "\n", &lastp);
    123 		if (!p1 || !p2 || !argv[2]) {
    124 			warnx("%s: line %d format error", actfile, linenum);
    125 			continue;
    126 		}
    127 		if (fnmatch(p1, tty, 0) || fnmatch(p2, act, 0))
    128 			continue;
    129 		/* OK, this is a match.  Run the command. */
    130 		pid = fork();
    131 		if (pid == -1) {
    132 			warnx("fork failed: %s", strerror(errno));
    133 			continue;
    134 		}
    135 		if (pid == 0) {
    136 			/* This is the child. */
    137 			error = execve(argv[0],
    138 			    (char *const *)__UNCONST(argv),
    139 			    (char *const *)__UNCONST(envp));
    140 			/* If we get here, it is an error. */
    141 			warnx("%s: line %d: exec failed: %s",
    142 				  actfile, linenum, strerror(errno));
    143 			_exit(1);
    144 		}
    145 		/* This is the parent. */
    146 		error = waitpid(pid, &status, 0);
    147 		if (error == -1) {
    148 			warnx("%s: line %d: wait failed: %s",
    149 				  actfile, linenum, strerror(errno));
    150 			continue;
    151 		}
    152 		if (WTERMSIG(status)) {
    153 			warnx("%s: line %d: child died with signal %d",
    154 				  actfile, linenum, WTERMSIG(status));
    155 			continue;
    156 		}
    157 	}
    158 	fclose(fp);
    159 	return status;
    160 }
    161