/*      $NetBSD: ttyaction.c,v 1.19 2008/04/28 20:23:03 martin Exp $    */

/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Gordon W. Ross.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

/*
* For each matching "tty" and "action" run the "command."
* See fnmatch() for matching the tty name.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: ttyaction.c,v 1.19 2008/04/28 20:23:03 martin Exp $");
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/wait.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "util.h"

#ifndef _PATH_TTYACTION
#define _PATH_TTYACTION "/etc/ttyaction"
#endif

static const char *actfile = _PATH_TTYACTION;
static const char *pathenv = "PATH=" _PATH_STDPATH;

int
ttyaction(const char *tty, const char *act, const char *user)
{
       FILE *fp;
       char *p1, *p2;
       const char *argv[4];
       const char *envp[8];
       char *lastp;
       char line[1024];
       char env_tty[64];
       char env_act[64];
       char env_user[256];
       int error, linenum, status;
       pid_t pid;

       _DIAGASSERT(tty != NULL);
       _DIAGASSERT(act != NULL);
       _DIAGASSERT(user != NULL);

       fp = fopen(actfile, "r");
       if (fp == NULL)
               return 0;

       /* Skip the "/dev/" part of the first arg. */
       if (!strncmp(tty, "/dev/", (size_t)5))
               tty += 5;

       /* Args will be: "sh -c ..." */
       argv[0] = _PATH_BSHELL;
       argv[1] = "-c";
       argv[2] = NULL; /* see below */
       argv[3] = NULL;

       /*
        * Environment needs: TTY, ACT, USER
        */
       snprintf(env_tty, sizeof(env_tty), "TTY=%s", tty);
       snprintf(env_act, sizeof(env_act), "ACT=%s", act);
       snprintf(env_user, sizeof(env_user), "USER=%s", user);
       envp[0] = pathenv;
       envp[1] = env_tty;
       envp[2] = env_act;
       envp[3] = env_user;
       envp[4] = NULL;

       linenum = 0;
       status = 0;
       while (fgets(line, (int)sizeof(line), fp)) {
               linenum++;

               /* Allow comment lines. */
               if (line[0] == '#')
                       continue;

               p1 = strtok_r(line, " \t", &lastp);
               p2 = strtok_r(NULL, " \t", &lastp);
               /* This arg goes to end of line. */
               argv[2] = strtok_r(NULL, "\n", &lastp);
               if (!p1 || !p2 || !argv[2]) {
                       warnx("%s: line %d format error", actfile, linenum);
                       continue;
               }
               if (fnmatch(p1, tty, 0) || fnmatch(p2, act, 0))
                       continue;
               /* OK, this is a match.  Run the command. */
               pid = fork();
               if (pid == -1) {
                       warnx("fork failed: %s", strerror(errno));
                       continue;
               }
               if (pid == 0) {
                       /* This is the child. */
                       error = execve(argv[0],
                           (char *const *)__UNCONST(argv),
                           (char *const *)__UNCONST(envp));
                       /* If we get here, it is an error. */
                       warnx("%s: line %d: exec failed: %s",
                                 actfile, linenum, strerror(errno));
                       _exit(1);
               }
               /* This is the parent. */
               error = waitpid(pid, &status, 0);
               if (error == -1) {
                       warnx("%s: line %d: wait failed: %s",
                                 actfile, linenum, strerror(errno));
                       continue;
               }
               if (WTERMSIG(status)) {
                       warnx("%s: line %d: child died with signal %d",
                                 actfile, linenum, WTERMSIG(status));
                       continue;
               }
       }
       fclose(fp);
       return status;
}