1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/param.h> 33 #include <sys/stat.h> 34 35 #include <err.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <signal.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 static void dofile(void); 45 static void usage(void) __dead2; 46 47 #define FILENAME "nohup.out" 48 /* 49 * POSIX mandates that we exit with: 50 * 126 - If the utility was found, but failed to execute. 51 * 127 - If any other error occurred. 52 */ 53 #define EXIT_NOEXEC 126 54 #define EXIT_NOTFOUND 127 55 #define EXIT_MISC 127 56 57 int 58 main(int argc, char *argv[]) 59 { 60 int exit_status; 61 62 while (getopt(argc, argv, "") != -1) 63 usage(); 64 argc -= optind; 65 argv += optind; 66 if (argc < 1) 67 usage(); 68 69 if (isatty(STDOUT_FILENO)) 70 dofile(); 71 if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) 72 /* may have just closed stderr */ 73 err(EXIT_MISC, "%s", argv[0]); 74 75 (void)signal(SIGHUP, SIG_IGN); 76 77 execvp(*argv, argv); 78 exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC; 79 err(exit_status, "%s", argv[0]); 80 } 81 82 static void 83 dofile(void) 84 { 85 int fd; 86 char path[MAXPATHLEN]; 87 const char *p; 88 89 /* 90 * POSIX mandates if the standard output is a terminal, the standard 91 * output is appended to nohup.out in the working directory. Failing 92 * that, it will be appended to nohup.out in the directory obtained 93 * from the HOME environment variable. If file creation is required, 94 * the mode_t is set to S_IRUSR | S_IWUSR. 95 */ 96 p = FILENAME; 97 fd = open(p, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR); 98 if (fd != -1) 99 goto dupit; 100 if ((p = getenv("HOME")) != NULL && *p != '\0' && 101 (size_t)snprintf(path, sizeof(path), "%s/%s", p, FILENAME) < 102 sizeof(path)) { 103 fd = open(p = path, O_RDWR | O_CREAT | O_APPEND, 104 S_IRUSR | S_IWUSR); 105 if (fd != -1) 106 goto dupit; 107 } 108 errx(EXIT_MISC, "can't open a nohup.out file"); 109 110 dupit: 111 if (dup2(fd, STDOUT_FILENO) == -1) 112 err(EXIT_MISC, NULL); 113 (void)fprintf(stderr, "appending output to %s\n", p); 114 } 115 116 static void 117 usage(void) 118 { 119 (void)fprintf(stderr, "usage: nohup [--] utility [arguments]\n"); 120 exit(EXIT_MISC); 121 } 122