1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #include "lint.h" 28 #include "file64.h" 29 #include "mtlib.h" 30 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <unistd.h> 34 #include <fcntl.h> 35 36 #include "stdiom.h" 37 38 /* 39 * Use fork/setsid/fork to go into background and permanently remove 40 * controlling terminal. 41 */ 42 int 43 daemon(int nochdir, int noclose) 44 { 45 int retv, fd; 46 47 /* 48 * By the first fork+setsid, we disconnect from our current controlling 49 * terminal and become a session group leader. 50 */ 51 retv = fork(); 52 if (retv == -1) 53 return (-1); 54 if (retv != 0) 55 _exit(EXIT_SUCCESS); 56 if (setsid() == -1) 57 return (-1); 58 /* 59 * By forking again without calling setsid again, we make certain 60 * that we are not the session group leader and can never reacquire 61 * a controlling terminal. 62 */ 63 retv = fork(); 64 if (retv == -1) 65 return (-1); 66 if (retv != 0) 67 _exit(EXIT_SUCCESS); 68 69 if (nochdir == 0) 70 (void) chdir("/"); 71 72 if (noclose == 0) { 73 /* 74 * Missing the PRIV_FILE_READ privilege may be one of the 75 * reasons that prevent the opening of /dev/null to succeed. 76 */ 77 if ((fd = open("/dev/null", O_RDWR)) == -1) 78 return (-1); 79 80 /* 81 * Also, if any of the descriptor redirects fails we should 82 * return with error to signal to the caller that his request 83 * cannot be fulfilled properly. It is up to the caller to 84 * do the cleanup. 85 */ 86 if ((fd != STDIN_FILENO) && (dup2(fd, STDIN_FILENO) < 0)) { 87 (void) close(fd); 88 return (-1); 89 } 90 if ((fd != STDOUT_FILENO) && (dup2(fd, STDOUT_FILENO) < 0)) { 91 (void) close(fd); 92 return (-1); 93 } 94 if ((fd != STDERR_FILENO) && (dup2(fd, STDERR_FILENO) < 0)) { 95 (void) close(fd); 96 return (-1); 97 } 98 99 if (fd > STDERR_FILENO) 100 (void) close(fd); 101 } 102 return (0); 103 } 104