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nohup.c revision 1.1 
      1 /*
      2  * Copyright (c) 1989 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 char copyright[] =
     36 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 static char sccsid[] = "@(#)nohup.c	5.4 (Berkeley) 6/1/90";
     42 #endif /* not lint */
     43 
     44 #include <sys/param.h>
     45 #include <sys/signal.h>
     46 #include <sys/file.h>
     47 #include <unistd.h>
     48 #include <stdio.h>
     49 
     50 extern int errno;
     51 
     52 main(argc, argv)
     53 	int argc;
     54 	char **argv;
     55 {
     56 	char *strerror();
     57 
     58 	if (argc < 2)
     59 		usage();
     60 
     61 	if (isatty(STDOUT_FILENO))
     62 		dofile();
     63 	if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
     64 		/* may have just closed stderr */
     65 		(void)fprintf(stdin, "nohup: %s\n", strerror(errno));
     66 		exit(1);
     67 	}
     68 
     69 	(void)signal(SIGHUP, SIG_IGN);
     70 	(void)signal(SIGQUIT, SIG_IGN);
     71 
     72 	execvp(argv[1], &argv[1]);
     73 	(void)fprintf(stderr,
     74 	    "nohup: %s: %s\n", argv[1], strerror(errno));
     75 	exit(1);
     76 }
     77 
     78 dofile()
     79 {
     80 	int fd;
     81 	char *p, path[MAXPATHLEN];
     82 	off_t lseek();
     83 	char *getenv(), *strcpy(), *strcat(), *strerror();
     84 
     85 #define	FILENAME	"nohup.out"
     86 	p = FILENAME;
     87 	if ((fd = open(p, O_RDWR|O_CREAT, 0600)) >= 0)
     88 		goto dupit;
     89 	if (p = getenv("HOME")) {
     90 		(void)strcpy(path, p);
     91 		(void)strcat(path, "/");
     92 		(void)strcat(path, FILENAME);
     93 		if ((fd = open(p = path, O_RDWR|O_CREAT, 0600)) >= 0)
     94 			goto dupit;
     95 	}
     96 	(void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
     97 	exit(1);
     98 
     99 dupit:	(void)lseek(fd, 0L, SEEK_END);
    100 	if (dup2(fd, STDOUT_FILENO) == -1) {
    101 		(void)fprintf(stderr, "nohup: %s\n", strerror(errno));
    102 		exit(1);
    103 	}
    104 	(void)fprintf(stderr, "sending output to %s\n", p);
    105 }
    106 
    107 usage()
    108 {
    109 	(void)fprintf(stderr, "usage: nohup command\n");
    110 	exit(1);
    111 }
    112