nohup/nohup.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Portions copyright (c) 2007 Apple Inc.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #if 0
  32 #ifndef lint
  33 static const char copyright[] =
  34 "@(#) Copyright (c) 1989, 1993\n\
  35         The Regents of the University of California.  All rights reserved.\n";
  36 #endif /* not lint */
  37
  38 #ifndef lint
  39 static char sccsid[] = "@(#)nohup.c     8.1 (Berkeley) 6/6/93";
  40 #endif /* not lint */
  41 #endif
  42 #include <sys/cdefs.h>
  43 #ifndef __APPLE__
  44 __FBSDID("$FreeBSD: src/usr.bin/nohup/nohup.c,v 1.10 2003/05/03 19:44:46 obrien Exp $");
  45 #endif
  46
  47 #include <sys/param.h>
  48 #include <sys/stat.h>
  49
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <fcntl.h>
  53 #include <signal.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58
  59 #ifdef __APPLE__
  60 #include <TargetConditionals.h>
  61 #include <vproc.h>
  62 #include <vproc_priv.h>
  63 #endif
  64
  65 static void dofile(void);
  66 static void usage(void);
  67
  68 #define FILENAME        "nohup.out"
  69 /*
  70  * POSIX mandates that we exit with:
  71  * 126 - If the utility was found, but failed to execute.
  72  * 127 - If any other error occurred.
  73  */
  74 #define EXIT_NOEXEC     126
  75 #define EXIT_NOTFOUND   127
  76 #define EXIT_MISC       127
  77
  78 int
  79 main(int argc, char *argv[])
  80 {
  81         int exit_status;
  82
  83         while (getopt(argc, argv, "") != -1)
  84                 usage();
  85         argc -= optind;
  86         argv += optind;
  87         if (argc < 1)
  88                 usage();
  89
  90         if (isatty(STDOUT_FILENO))
  91                 dofile();
  92         if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
  93                 /* may have just closed stderr */
  94                 err(EXIT_MISC, "%s", argv[0]);
  95
  96         (void)signal(SIGHUP, SIG_IGN);
  97
  98 #if defined(__APPLE__) && !TARGET_OS_EMBEDDED
  99         if (_vprocmgr_detach_from_console(0) != NULL)
 100                 err(EXIT_MISC, "can't detach from console");
 101 #endif
 102         execvp(*argv, argv);
 103         exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
 104         err(exit_status, "%s", argv[0]);
 105 }
 106
 107 static void
 108 dofile(void)
 109 {
 110         int fd;
 111         char path[MAXPATHLEN];
 112         const char *p;
 113
 114         /*
 115          * POSIX mandates if the standard output is a terminal, the standard
 116          * output is appended to nohup.out in the working directory.  Failing
 117          * that, it will be appended to nohup.out in the directory obtained
 118          * from the HOME environment variable.  If file creation is required,
 119          * the mode_t is set to S_IRUSR | S_IWUSR.
 120          */
 121         p = FILENAME;
 122         fd = open(p, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
 123         if (fd != -1)
 124                 goto dupit;
 125         if ((p = getenv("HOME")) != NULL && *p != '\0' &&
 126             (size_t)snprintf(path, sizeof(path), "%s/%s", p, FILENAME) <
 127             sizeof(path)) {
 128                 fd = open(p = path, O_RDWR | O_CREAT | O_APPEND,
 129                     S_IRUSR | S_IWUSR);
 130                 if (fd != -1)
 131                         goto dupit;
 132         }
 133         errx(EXIT_MISC, "can't open a nohup.out file");
 134
 135 dupit:
 136 #ifdef __APPLE__
 137         (void)lseek(fd, 0L, SEEK_END);
 138 #endif
 139         if (dup2(fd, STDOUT_FILENO) == -1)
 140                 err(EXIT_MISC, NULL);
 141         (void)fprintf(stderr, "appending output to %s\n", p);
 142 }
 143
 144 static void
 145 usage(void)
 146 {
 147         (void)fprintf(stderr, "usage: nohup [--] utility [arguments]\n");
 148         exit(EXIT_MISC);
 149 }