lib/libutil/ttyaction.c

   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 }