Import Upstream version 1.0.23

src/dropin.c

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+/*
+    dropin.c -- a set of drop-in replacements for libc functions
+    Copyright (C) 2000-2005 Ivo Timmermans,
+                  2000-2011 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_GET_CURRENT_DIR_NAME
+/*
+  Replacement for the GNU get_current_dir_name function:
+
+  get_current_dir_name will malloc(3) an array big enough to hold the
+  current directory name.  If the environment variable PWD is set, and
+  its value is correct, then that value will be returned.
+*/
+char *get_current_dir_name(void) {
+	size_t size;
+	char *buf;
+	char *r;
+
+	/* Start with 100 bytes.  If this turns out to be insufficient to
+	   contain the working directory, double the size.  */
+	size = 100;
+	buf = xmalloc(size);
+
+	errno = 0;					/* Success */
+	r = getcwd(buf, size);
+
+	/* getcwd returns NULL and sets errno to ERANGE if the bufferspace
+	   is insufficient to contain the entire working directory.  */
+	while(r == NULL && errno == ERANGE) {
+		free(buf);
+		size <<= 1;				/* double the size */
+		buf = xmalloc(size);
+		r = getcwd(buf, size);
+	}
+
+	return buf;
+}
+#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);
+	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