usr.bin/nohup/nohup.c

   1 /*      $NetBSD: nohup.c,v 1.13 2008/07/21 14:19:24 lukem Exp $ */
   2
   3 /*
   4  * Copyright (c) 1989 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __COPYRIGHT("@(#) Copyright (c) 1989\
  35  The Regents of the University of California.  All rights reserved.");
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)nohup.c     5.4 (Berkeley) 6/1/90";
  41 #endif
  42 __RCSID("$NetBSD: nohup.c,v 1.13 2008/07/21 14:19:24 lukem Exp $");
  43 #endif /* not lint */
  44
  45 #include <sys/param.h>
  46 #include <sys/file.h>
  47 #include <sys/stat.h>
  48 #include <fcntl.h>
  49 #include <unistd.h>
  50 #include <signal.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <errno.h>
  55
  56 static void dofile __P((void));
  57 static void usage __P((void));
  58 int main __P((int, char **));
  59
  60 /* nohup shall exit with one of the following values:
  61    126 - The utility was found but could not be invoked.
  62    127 - An error occurred in the nohup utility, or the utility could
  63          not be found. */
  64 #define EXIT_NOEXEC     126
  65 #define EXIT_NOTFOUND   127
  66 #define EXIT_MISC       127
  67
  68 int
  69 main(argc, argv)
  70         int argc;
  71         char **argv;
  72 {
  73         int exit_status;
  74
  75         while (getopt(argc, argv, "") != -1) {
  76                 usage();
  77         }
  78         argc -= optind;
  79         argv += optind;
  80
  81         if (argc < 1)
  82                 usage();
  83
  84         if (isatty(STDOUT_FILENO))
  85                 dofile();
  86         if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
  87                 /* may have just closed stderr */
  88                 (void)fprintf(stdin, "nohup: %s\n", strerror(errno));
  89                 exit(EXIT_MISC);
  90         }
  91
  92         /* The nohup utility shall take the standard action for all signals
  93            except that SIGHUP shall be ignored. */
  94         (void)signal(SIGHUP, SIG_IGN);
  95
  96         execvp(argv[0], &argv[0]);
  97         exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
  98         (void)fprintf(stderr, "nohup: %s: %s\n", argv[0], strerror(errno));
  99         exit(exit_status);
 100 }
 101
 102 static void
 103 dofile()
 104 {
 105         int fd;
 106         char path[MAXPATHLEN];
 107         const char *p;
 108
 109         /* If the standard output is a terminal, all output written to
 110            its standard output shall be appended to the end of the file
 111            nohup.out in the current directory.  If nohup.out cannot be
 112            created or opened for appending, the output shall be appended
 113            to the end of the file nohup.out in the directory specified
 114            by the HOME environment variable.
 115
 116            If a file is created, the file's permission bits shall be
 117            set to S_IRUSR | S_IWUSR. */
 118 #define FILENAME        "nohup.out"
 119         p = FILENAME;
 120         if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 121                 goto dupit;
 122         if ((p = getenv("HOME")) != NULL) {
 123                 (void)strlcpy(path, p, sizeof(path));
 124                 (void)strlcat(path, "/", sizeof(path));
 125                 (void)strlcat(path, FILENAME, sizeof(path));
 126                 if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 127                         goto dupit;
 128         }
 129         (void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
 130         exit(EXIT_MISC);
 131
 132 dupit:  (void)lseek(fd, 0L, SEEK_END);
 133         if (dup2(fd, STDOUT_FILENO) == -1) {
 134                 (void)fprintf(stderr, "nohup: %s\n", strerror(errno));
 135                 exit(EXIT_MISC);
 136         }
 137         (void)fprintf(stderr, "sending output to %s\n", p);
 138 }
 139
 140 static void
 141 usage()
 142 {
 143         (void)fprintf(stderr, "usage: nohup utility [argument ...]\n");
 144         exit(EXIT_MISC);
 145 }