shell_cmds/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 #include <libiosexec.h>
  66
  67 static void dofile(void);
  68 static void usage(void);
  69
  70 #define FILENAME        "nohup.out"
  71 /*
  72  * POSIX mandates that we exit with:
  73  * 126 - If the utility was found, but failed to execute.
  74  * 127 - If any other error occurred.
  75  */
  76 #define EXIT_NOEXEC     126
  77 #define EXIT_NOTFOUND   127
  78 #define EXIT_MISC       127
  79
  80 int
  81 main(int argc, char *argv[])
  82 {
  83         int exit_status;
  84
  85         while (getopt(argc, argv, "") != -1)
  86                 usage();
  87         argc -= optind;
  88         argv += optind;
  89         if (argc < 1)
  90                 usage();
  91
  92         if (isatty(STDOUT_FILENO))
  93                 dofile();
  94         if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
  95                 /* may have just closed stderr */
  96                 err(EXIT_MISC, "%s", argv[0]);
  97
  98         (void)signal(SIGHUP, SIG_IGN);
  99
 100 #if defined(__APPLE__) && !(TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
 101         if (_vprocmgr_detach_from_console(0) != NULL)
 102                 err(EXIT_MISC, "can't detach from console");
 103 #endif
 104         execvp(*argv, argv);
 105         exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
 106         err(exit_status, "%s", argv[0]);
 107 }
 108
 109 static void
 110 dofile(void)
 111 {
 112         int fd;
 113         char path[MAXPATHLEN];
 114         const char *p;
 115
 116         /*
 117          * POSIX mandates if the standard output is a terminal, the standard
 118          * output is appended to nohup.out in the working directory.  Failing
 119          * that, it will be appended to nohup.out in the directory obtained
 120          * from the HOME environment variable.  If file creation is required,
 121          * the mode_t is set to S_IRUSR | S_IWUSR.
 122          */
 123         p = FILENAME;
 124         fd = open(p, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
 125         if (fd != -1)
 126                 goto dupit;
 127         if ((p = getenv("HOME")) != NULL && *p != '\0' &&
 128             (size_t)snprintf(path, sizeof(path), "%s/%s", p, FILENAME) <
 129             sizeof(path)) {
 130                 fd = open(p = path, O_RDWR | O_CREAT | O_APPEND,
 131                     S_IRUSR | S_IWUSR);
 132                 if (fd != -1)
 133                         goto dupit;
 134         }
 135         errx(EXIT_MISC, "can't open a nohup.out file");
 136
 137 dupit:
 138 #ifdef __APPLE__
 139         (void)lseek(fd, 0L, SEEK_END);
 140 #endif
 141         if (dup2(fd, STDOUT_FILENO) == -1)
 142                 err(EXIT_MISC, NULL);
 143         (void)fprintf(stderr, "appending output to %s\n", p);
 144 }
 145
 146 static void
 147 usage(void)
 148 {
 149         (void)fprintf(stderr, "usage: nohup [--] utility [arguments]\n");
 150         exit(EXIT_MISC);
 151 }