nohup/nohup.c

   1 /*      $NetBSD: nohup.c,v 1.8 1997/12/23 18:21:34 ross 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. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 #ifndef lint
  38 __COPYRIGHT(
  39     "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
  40  All rights reserved.\n");
  41 #endif /* not lint */
  42
  43 #ifndef lint
  44 #if 0
  45 static char sccsid[] = "@(#)nohup.c     5.4 (Berkeley) 6/1/90";
  46 #endif
  47 __RCSID("$NetBSD: nohup.c,v 1.8 1997/12/23 18:21:34 ross Exp $");
  48 #endif /* not lint */
  49
  50 #include <sys/param.h>
  51 #include <sys/file.h>
  52 #include <sys/stat.h>
  53 #include <fcntl.h>
  54 #include <unistd.h>
  55 #include <signal.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <errno.h>
  60
  61 static void dofile __P((void));
  62 static void usage __P((void));
  63 int main __P((int, char **));
  64
  65 /* nohup shall exit with one of the following values:
  66    126 - The utility was found but could not be invoked.
  67    127 - An error occured in the nohup utility, or the utility could
  68          not be found. */
  69 #define EXIT_NOEXEC     126
  70 #define EXIT_NOTFOUND   127
  71 #define EXIT_MISC       127
  72
  73 int
  74 main(argc, argv)
  75         int argc;
  76         char **argv;
  77 {
  78         int exit_status;
  79
  80         if (argc < 2)
  81                 usage();
  82
  83         if (isatty(STDOUT_FILENO))
  84                 dofile();
  85         if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
  86                 /* may have just closed stderr */
  87                 (void)fprintf(stdin, "nohup: %s\n", strerror(errno));
  88                 exit(EXIT_MISC);
  89         }
  90
  91         /* The nohup utility shall take the standard action for all signals
  92            except that SIGHUP shall be ignored. */
  93         (void)signal(SIGHUP, SIG_IGN);
  94
  95         execvp(argv[1], &argv[1]);
  96         exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
  97         (void)fprintf(stderr, "nohup: %s: %s\n", argv[1], strerror(errno));
  98         exit(exit_status);
  99 }
 100
 101 static void
 102 dofile()
 103 {
 104         int fd;
 105         char *p, path[MAXPATHLEN];
 106
 107         /* If the standard output is a terminal, all output written to
 108            its standard output shall be appended to the end of the file
 109            nohup.out in the current directory.  If nohup.out cannot be
 110            created or opened for appending, the output shall be appended
 111            to the end of the file nohup.out in the directory specified
 112            by the HOME environment variable.
 113
 114            If a file is created, the file's permission bits shall be
 115            set to S_IRUSR | S_IWUSR. */
 116 #define FILENAME        "nohup.out"
 117         p = FILENAME;
 118         if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 119                 goto dupit;
 120         if ((p = getenv("HOME")) != NULL) {
 121                 (void)strcpy(path, p);
 122                 (void)strcat(path, "/");
 123                 (void)strcat(path, FILENAME);
 124                 if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
 125                         goto dupit;
 126         }
 127         (void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
 128         exit(EXIT_MISC);
 129
 130 dupit:  (void)lseek(fd, 0L, SEEK_END);
 131         if (dup2(fd, STDOUT_FILENO) == -1) {
 132                 (void)fprintf(stderr, "nohup: %s\n", strerror(errno));
 133                 exit(EXIT_MISC);
 134         }
 135         (void)fprintf(stderr, "sending output to %s\n", p);
 136 }
 137
 138 static void
 139 usage()
 140 {
 141         (void)fprintf(stderr, "usage: nohup command\n");
 142         exit(EXIT_MISC);
 143 }