usr.bin/nohup/nohup.c

   1 /*      $NetBSD: nohup.c,v 1.15 2011/09/06 18:24:15 joerg 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 1.15 2011/09/06 18:24:15 joerg 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(void);
  57 __dead static void usage(void);
  58
  59 /* nohup shall exit with one of the following values:
  60    126 - The utility was found but could not be invoked.
  61    127 - An error occurred in the nohup utility, or the utility could
  62          not be found. */
  63 #define EXIT_NOEXEC     126
  64 #define EXIT_NOTFOUND   127
  65 #define EXIT_MISC       127
  66
  67 int
  68 main(int argc, char **argv)
  69 {
  70         int exit_status;
  71
  72         while (getopt(argc, argv, "") != -1) {
  73                 usage();
  74         }
  75         argc -= optind;
  76         argv += optind;
  77
  78         if (argc < 1)
  79                 usage();
  80
  81         if (isatty(STDOUT_FILENO))
  82                 dofile();
  83         if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
  84                 /* may have just closed stderr */
  85                 (void)fprintf(stdin, "nohup: %s\n", strerror(errno));
  86                 exit(EXIT_MISC);
  87         }
  88
  89         /* The nohup utility shall take the standard action for all signals
  90            except that SIGHUP shall be ignored. */
  91         (void)signal(SIGHUP, SIG_IGN);
  92
  93         execvp(argv[0], &argv[0]);
  94         exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
  95         (void)fprintf(stderr, "nohup: %s: %s\n", argv[0], strerror(errno));
  96         exit(exit_status);
  97 }
  98
  99 static void
 100 dofile(void)
 101 {
 102         int fd;
 103         char path[MAXPATHLEN];
 104         const char *p;
 105
 106         /* If the standard output is a terminal, all output written to
 107            its standard output shall be appended to the end of the file
 108            nohup.out in the current directory.  If nohup.out cannot be
 109            created or opened for appending, the output shall be appended
 110            to the end of the file nohup.out in the directory specified
 111            by the HOME environment variable.
 112
 113            If a file is created, the file's permission bits shall be
 114            set to S_IRUSR | S_IWUSR. */
 115 #define FILENAME        "nohup.out"
 116         p = FILENAME;
 117         if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 118                 goto dupit;
 119         if ((p = getenv("HOME")) != NULL) {
 120                 (void)strlcpy(path, p, sizeof(path));
 121                 (void)strlcat(path, "/", sizeof(path));
 122                 (void)strlcat(path, FILENAME, sizeof(path));
 123                 if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 124                         goto dupit;
 125         }
 126         (void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
 127         exit(EXIT_MISC);
 128
 129 dupit:  (void)lseek(fd, 0L, SEEK_END);
 130         if (dup2(fd, STDOUT_FILENO) == -1) {
 131                 (void)fprintf(stderr, "nohup: %s\n", strerror(errno));
 132                 exit(EXIT_MISC);
 133         }
 134         (void)fprintf(stderr, "sending output to %s\n", p);
 135 }
 136
 137 static void
 138 usage(void)
 139 {
 140         (void)fprintf(stderr, "usage: nohup utility [argument ...]\n");
 141         exit(EXIT_MISC);
 142 }