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- /*
- dropin.c -- a set of drop-in replacements for libc functions
- Copyright (C) 2000-2005 Ivo Timmermans,
- 2000-2016 Guus Sliepen <guus@tinc-vpn.org>
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
- #include "system.h"
- #include "xalloc.h"
- #ifndef HAVE_DAEMON
- /*
- Replacement for the daemon() function.
- The daemon() function is for programs wishing to detach themselves
- from the controlling terminal and run in the background as system
- daemons.
- Unless the argument nochdir is non-zero, daemon() changes the
- current working directory to the root (``/'').
- Unless the argument noclose is non-zero, daemon() will redirect
- standard input, standard output and standard error to /dev/null.
- */
- int daemon(int nochdir, int noclose) {
- #ifdef HAVE_FORK
- pid_t pid;
- int fd;
- pid = fork();
- /* Check if forking failed */
- if(pid < 0) {
- perror("fork");
- exit(-1);
- }
- /* If we are the parent, terminate */
- if(pid) {
- exit(0);
- }
- /* Detach by becoming the new process group leader */
- if(setsid() < 0) {
- perror("setsid");
- return -1;
- }
- /* Change working directory to the root (to avoid keeping mount
- points busy) */
- if(!nochdir) {
- chdir("/");
- }
- /* Redirect stdin/out/err to /dev/null */
- if(!noclose) {
- fd = open("/dev/null", O_RDWR);
- if(fd < 0) {
- perror("opening /dev/null");
- return -1;
- } else {
- dup2(fd, 0);
- dup2(fd, 1);
- dup2(fd, 2);
- }
- }
- return 0;
- #else
- return -1;
- #endif
- }
- #endif
- #ifndef HAVE_ASPRINTF
- int asprintf(char **buf, const char *fmt, ...) {
- int result;
- va_list ap;
- va_start(ap, fmt);
- result = vasprintf(buf, fmt, ap);
- va_end(ap);
- return result;
- }
- int vasprintf(char **buf, const char *fmt, va_list ap) {
- int status;
- va_list aq;
- int len;
- len = 4096;
- *buf = xmalloc(len);
- va_copy(aq, ap);
- status = vsnprintf(*buf, len, fmt, aq);
- buf[len - 1] = 0;
- va_end(aq);
- if(status >= 0) {
- *buf = xrealloc(*buf, status + 1);
- }
- if(status > len - 1) {
- len = status;
- va_copy(aq, ap);
- status = vsnprintf(*buf, len, fmt, aq);
- va_end(aq);
- }
- return status;
- }
- #endif
- #ifndef HAVE_GETTIMEOFDAY
- int gettimeofday(struct timeval *tv, void *tz) {
- tv->tv_sec = time(NULL);
- tv->tv_usec = 0;
- return 0;
- }
- #endif
- #ifndef HAVE_USLEEP
- int usleep(long long usec) {
- struct timeval tv = {usec / 1000000, (usec / 1000) % 1000};
- select(0, NULL, NULL, NULL, &tv);
- return 0;
- }
- #endif
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