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