1 /* $OpenBSD: nohup.c,v 1.16 2015/11/09 16:52:32 deraadt Exp $ */ 2 /* $NetBSD: nohup.c,v 1.6 1995/08/31 23:35:25 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 1989 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/file.h> 34 #include <sys/stat.h> 35 #include <fcntl.h> 36 #include <unistd.h> 37 #include <signal.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <errno.h> 42 #include <limits.h> 43 #include <err.h> 44 45 static void dofile(void); 46 __dead static void usage(void); 47 48 /* 49 * nohup shall exit with one of the following values: 50 * 126 - The utility was found but could not be invoked. 51 * 127 - An error occurred in the nohup utility, or the utility could 52 * not be found. 53 */ 54 #define EXIT_NOEXEC 126 55 #define EXIT_NOTFOUND 127 56 #define EXIT_MISC 127 57 58 /* 59 * If the standard output is a terminal, all output written to 60 * its standard output shall be appended to the end of the file 61 * nohup.out in the current directory. If nohup.out cannot be 62 * created or opened for appending, the output shall be appended 63 * to the end of the file nohup.out in the directory specified 64 * by the HOME environment variable. 65 * 66 * If a file is created, the file's permission bits shall be 67 * set to S_IRUSR | S_IWUSR. 68 */ 69 #define FILENAME "nohup.out" 70 71 int 72 main(int argc, char *argv[]) 73 { 74 int exit_status; 75 76 if (pledge("stdio rpath wpath cpath exec", NULL) == -1) 77 err(1, "pledge"); 78 79 if (argc < 2) 80 usage(); 81 82 if (isatty(STDOUT_FILENO)) 83 dofile(); 84 85 if (pledge("stdio exec", NULL) == -1) 86 err(1, "pledge"); 87 88 if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) { 89 /* may have just closed stderr */ 90 (void)fprintf(stdin, "nohup: %s\n", strerror(errno)); 91 exit(EXIT_MISC); 92 } 93 94 /* 95 * The nohup utility shall take the standard action for all signals 96 * except that SIGHUP shall be ignored. 97 */ 98 (void)signal(SIGHUP, SIG_IGN); 99 100 execvp(argv[1], &argv[1]); 101 exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC; 102 err(exit_status, "%s", argv[1]); 103 } 104 105 static void 106 dofile(void) 107 { 108 int fd; 109 const char *p; 110 char path[PATH_MAX]; 111 112 p = FILENAME; 113 if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0) 114 goto dupit; 115 if ((p = getenv("HOME")) != NULL && *p != '\0' && 116 (strlen(p) + strlen(FILENAME) + 1) < sizeof(path)) { 117 (void)strlcpy(path, p, sizeof(path)); 118 (void)strlcat(path, "/", sizeof(path)); 119 (void)strlcat(path, FILENAME, sizeof(path)); 120 if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0) 121 goto dupit; 122 } 123 errx(EXIT_MISC, "can't open a nohup.out file"); 124 125 dupit: 126 (void)lseek(fd, (off_t)0, SEEK_END); 127 if (dup2(fd, STDOUT_FILENO) == -1) 128 err(EXIT_MISC, NULL); 129 (void)fprintf(stderr, "sending output to %s\n", p); 130 } 131 132 __dead static void 133 usage(void) 134 { 135 (void)fprintf(stderr, "usage: nohup utility [arg ...]\n"); 136 exit(EXIT_MISC); 137 } 138