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nohup.c revision 1.6 
      1 /*	$NetBSD: nohup.c,v 1.6 1995/08/31 23:35:25 jtc 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 #ifndef lint
     37 char copyright[] =
     38 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
     39  All rights reserved.\n";
     40 #endif /* not lint */
     41 
     42 #ifndef lint
     43 #if 0
     44 static char sccsid[] = "@(#)nohup.c	5.4 (Berkeley) 6/1/90";
     45 #endif
     46 static char rcsid[] = "$NetBSD: nohup.c,v 1.6 1995/08/31 23:35:25 jtc Exp $";
     47 #endif /* not lint */
     48 
     49 #include <sys/param.h>
     50 #include <sys/file.h>
     51 #include <sys/stat.h>
     52 #include <fcntl.h>
     53 #include <unistd.h>
     54 #include <signal.h>
     55 #include <stdio.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <errno.h>
     59 
     60 static void dofile();
     61 static void usage();
     62 
     63 /* nohup shall exit with one of the following values:
     64    126 - The utility was found but could not be invoked.
     65    127 - An error occured in the nohup utility, or the utility could
     66          not be found. */
     67 #define EXIT_NOEXEC	126
     68 #define EXIT_NOTFOUND	127
     69 #define EXIT_MISC	127
     70 
     71 int
     72 main(argc, argv)
     73 	int argc;
     74 	char **argv;
     75 {
     76 	int exit_status;
     77 
     78 	if (argc < 2)
     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[1], &argv[1]);
     94 	exit_status = (errno = ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
     95 	(void)fprintf(stderr, "nohup: %s: %s\n", argv[1], strerror(errno));
     96 	exit(exit_status);
     97 }
     98 
     99 static void
    100 dofile()
    101 {
    102 	int fd;
    103 	char *p, path[MAXPATHLEN];
    104 
    105 	/* If the standard output is a terminal, all output written to
    106 	   its standard output shall be appended to the end of the file
    107 	   nohup.out in the current directory.  If nohup.out cannot be
    108 	   created or opened for appending, the output shall be appended
    109 	   to the end of the file nohup.out in the directory specified
    110 	   by the HOME environment variable.
    111 
    112 	   If a file is created, the file's permission bits shall be
    113 	   set to S_IRUSR | S_IWUSR. */
    114 #define	FILENAME	"nohup.out"
    115 	p = FILENAME;
    116 	if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
    117 		goto dupit;
    118 	if ((p = getenv("HOME")) != NULL) {
    119 		(void)strcpy(path, p);
    120 		(void)strcat(path, "/");
    121 		(void)strcat(path, FILENAME);
    122 		if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
    123 			goto dupit;
    124 	}
    125 	(void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
    126 	exit(EXIT_MISC);
    127 
    128 dupit:	(void)lseek(fd, 0L, SEEK_END);
    129 	if (dup2(fd, STDOUT_FILENO) == -1) {
    130 		(void)fprintf(stderr, "nohup: %s\n", strerror(errno));
    131 		exit(EXIT_MISC);
    132 	}
    133 	(void)fprintf(stderr, "sending output to %s\n", p);
    134 }
    135 
    136 static void
    137 usage()
    138 {
    139 	(void)fprintf(stderr, "usage: nohup command\n");
    140 	exit(EXIT_MISC);
    141 }
    142