1 /* $NetBSD: detach.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2015 5 * Cryptonector LLC. 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. Cryptonector LLC may not be used to endorse or promote products 16 * derived from this software without specific prior written 17 * 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 <config.h> 33 #include <errno.h> 34 #include <fcntl.h> 35 #ifdef WIN32 36 #include <io.h> 37 #include <stdlib.h> 38 #else 39 #include <unistd.h> 40 #endif 41 #include <krb5/roken.h> 42 43 #ifdef WIN32 44 #define dup2 _dup2 45 #endif 46 47 static int pipefds[2] = {-1, -1}; 48 49 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL 50 roken_detach_prep(int argc, char **argv, char *special_arg) 51 { 52 pid_t child; 53 char buf[1]; 54 ssize_t bytes; 55 int status; 56 57 pipefds[0] = -1; 58 pipefds[1] = -1; 59 60 #ifdef WIN32 61 if (_pipe(pipefds, 4, O_BINARY) == -1) 62 err(1, "failed to setup to detach daemon (_pipe failed)"); 63 #else 64 if (pipe(pipefds) == -1) 65 err(1, "failed to setup to detach daemon (pipe failed)"); 66 #endif 67 68 #ifndef WIN32 69 fflush(stdout); 70 child = fork(); 71 #else 72 { 73 intptr_t child_handle; 74 int write_side; 75 size_t i; 76 char *fildes; 77 char **new_argv; 78 79 new_argv = calloc(argc + 2, sizeof(*new_argv)); 80 if (new_argv == NULL) 81 err(1, "Out of memory"); 82 83 write_side = _dup(pipefds[1]); /* The new fd will be inherited */ 84 if (write_side == -1) 85 err(1, "Out of memory"); 86 87 if (asprintf(&fildes, "%d", write_side) == -1 || 88 fildes == NULL) 89 err(1, "failed to setup to detach daemon (_dup failed)"); 90 91 new_argv[0] = argv[0]; 92 new_argv[1] = special_arg; 93 new_argv[2] = fildes; 94 for (i = 1; argv[i] != NULL; i++) 95 new_argv[i + 1] = argv[i]; 96 new_argv[argc + 2] = NULL; 97 98 _flushall(); 99 child_handle = spawnvp(_P_NOWAIT, argv[0], new_argv); 100 if (child_handle == -1) 101 child = (pid_t)-1; 102 else 103 child = GetProcessId((HANDLE)child_handle); 104 } 105 #endif 106 if (child == (pid_t)-1) 107 err(1, "failed to setup to fork daemon (fork failed)"); 108 109 #ifndef WIN32 110 if (child == 0) { 111 int fd; 112 113 (void) close(pipefds[0]); 114 pipefds[0] = -1; 115 /* 116 * Keep stdout/stderr for now so output and errors prior to 117 * detach_finish() can be seen by the user. 118 */ 119 fd = open(_PATH_DEVNULL, O_RDWR, 0); 120 if (fd == -1) 121 err(1, "failed to open /dev/null"); 122 (void) dup2(fd, STDIN_FILENO); 123 if (fd > STDERR_FILENO) 124 (void) close(fd); 125 return; 126 } 127 #endif 128 129 (void) close(pipefds[1]); 130 pipefds[1] = -1; 131 do { 132 bytes = read(pipefds[0], buf, sizeof(buf)); 133 } while (bytes == -1 && errno == EINTR); 134 (void) close(pipefds[0]); 135 pipefds[0] = -1; 136 if (bytes == -1) { 137 /* 138 * No need to wait for the process. We've killed it. If it 139 * doesn't want to exit, we'd have to wait potentially forever, 140 * but we want to indicate failure to the user as soon as 141 * possible. A wait with timeout would end the same way 142 * (attempting to kill the process). 143 */ 144 err(1, "failed to setup daemon child (read from child pipe)"); 145 } 146 if (bytes == 0) { 147 warnx("daemon child preparation failed, waiting for child"); 148 status = wait_for_process(child); 149 if (SE_IS_ERROR(status) || SE_PROCSTATUS(status) != 0) 150 errx(SE_PROCSTATUS(status), 151 "daemon child preparation failed (child exited)"); 152 } 153 _exit(0); 154 } 155 156 #ifdef WIN32 157 #ifdef dup2 158 #undef dup2 159 #endif 160 #define dup2 _dup2 161 #endif 162 163 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL 164 roken_detach_finish(const char *dir, int daemon_child_fd) 165 { 166 char buf[1] = ""; 167 ssize_t bytes; 168 int fd; 169 170 rk_pidfile(NULL); 171 if (pipefds[1] == -1 && daemon_child_fd != -1) 172 pipefds[1] = daemon_child_fd; 173 if (pipefds[0] != -1) 174 (void) close(pipefds[0]); 175 if (pipefds[1] == -1) 176 return; 177 178 #ifdef HAVE_SETSID 179 if (setsid() == -1) 180 err(1, "failed to detach from tty"); 181 #endif 182 183 #ifndef WIN32 184 /* 185 * Hopefully we've written any pidfiles by now, if they had to be in 186 * the current directory... 187 * 188 * The daemons do re-open logs and so on, therefore this chdir() 189 * call needs to be optional for testing. 190 */ 191 if (dir != NULL && chdir(dir) == -1) 192 err(1, "failed to chdir to /"); 193 #endif 194 195 do { 196 bytes = write(pipefds[1], buf, sizeof(buf)); 197 } while (bytes == -1 && errno == EINTR); 198 if (bytes == -1) 199 err(1, "failed to signal parent while detaching"); 200 (void) close(pipefds[1]); 201 if (bytes != sizeof(buf)) 202 errx(1, "failed to signal parent while detaching"); 203 204 fd = open(_PATH_DEVNULL, O_RDWR, 0); 205 if (fd == -1) 206 err(1, "failed to open /dev/null"); 207 /* 208 * Maybe we should check that our output got written, if redirected 209 * to a file. File utils normally do this. 210 */ 211 (void) dup2(fd, STDOUT_FILENO); 212 (void) dup2(fd, STDERR_FILENO); 213 if (fd > 2) 214 (void) close(fd); 215 } 216