common.c - platform/external/dhcpcd - Git at Google

 /*
  * dhcpcd - DHCP client daemon
  * Copyright (c) 2006-2012 Roy Marples <roy@marples.name>
  * All rights reserved

  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 /* Needed define to get at getline for glibc and FreeBSD */
 #ifndef _GNU_SOURCE
 #  define _GNU_SOURCE
 #endif

 #include <sys/cdefs.h>

 #ifdef __APPLE__
 #  include <mach/mach_time.h>
 #  include <mach/kern_return.h>
 #endif

 #include <sys/param.h>
 #include <sys/time.h>

 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
 #ifdef BSD
 #  include <paths.h>
 #endif
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <syslog.h>
 #include <time.h>
 #include <unistd.h>

 #include "common.h"

 #ifndef _PATH_DEVNULL
 #  define _PATH_DEVNULL "/dev/null"
 #endif

 int clock_monotonic;
 static char *lbuf;
 static size_t lbuf_len;
 #ifdef DEBUG_MEMORY
 static char lbuf_set;
 #endif

 #ifdef DEBUG_MEMORY
 static void
 free_lbuf(void)
 {
 	free(lbuf);
 	lbuf = NULL;
 }
 #endif

 /* Handy routine to read very long lines in text files.
  * This means we read the whole line and avoid any nasty buffer overflows.
  * We strip leading space and avoid comment lines, making the code that calls
  * us smaller.
  * As we don't use threads, this API is clean too. */
 char *
 get_line(FILE * __restrict fp)
 {
 	char *p;
 	ssize_t bytes;

 #ifdef DEBUG_MEMORY
 	if (lbuf_set == 0) {
 		atexit(free_lbuf);
 		lbuf_set = 1;
 	}
 #endif

 	do {
 		bytes = getline(&lbuf, &lbuf_len, fp);
 		if (bytes == -1)
 			return NULL;
 		for (p = lbuf; *p == ' ' || *p == '\t'; p++)
 			;
 	} while (*p == '\0' || *p == '\n' || *p == '#' || *p == ';');
 	if (lbuf[--bytes] == '\n')
 		lbuf[bytes] = '\0';
 	return p;
 }

 int
 set_cloexec(int fd)
 {
 	int flags;

 	if ((flags = fcntl(fd, F_GETFD, 0)) == -1 ||
 	    fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
 	{
 		syslog(LOG_ERR, "fcntl: %m");
 		return -1;
 	}
 	return 0;
 }

 int
 set_nonblock(int fd)
 {
 	int flags;

 	if ((flags = fcntl(fd, F_GETFL, 0)) == -1 ||
 	    fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
 	{
 		syslog(LOG_ERR, "fcntl: %m");
 		return -1;
 	}
 	return 0;
 }

 /* Handy function to get the time.
  * We only care about time advancements, not the actual time itself
  * Which is why we use CLOCK_MONOTONIC, but it is not available on all
  * platforms.
  */
 #define NO_MONOTONIC "host does not support a monotonic clock - timing can skew"
 int
 get_monotonic(struct timeval *tp)
 {
 	static int posix_clock_set = 0;
 #if defined(_POSIX_MONOTONIC_CLOCK) && defined(CLOCK_MONOTONIC)
 	struct timespec ts;
 	static clockid_t posix_clock;

 	if (!posix_clock_set) {
 		if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
 			posix_clock = CLOCK_MONOTONIC;
 			clock_monotonic = posix_clock_set = 1;
 		}
 	}

 	if (clock_monotonic) {
 		if (clock_gettime(posix_clock, &ts) == 0) {
 			tp->tv_sec = ts.tv_sec;
 			tp->tv_usec = ts.tv_nsec / 1000;
 			return 0;
 		}
 	}
 #elif defined(__APPLE__)
 #define NSEC_PER_SEC 1000000000
 	/* We can use mach kernel functions here.
 	 * This is crap though - why can't they implement clock_gettime?*/
 	static struct mach_timebase_info info = { 0, 0 };
 	static double factor = 0.0;
 	uint64_t nano;
 	long rem;

 	if (!posix_clock_set) {
 		if (mach_timebase_info(&info) == KERN_SUCCESS) {
 			factor = (double)info.numer / (double)info.denom;
 			clock_monotonic = posix_clock_set = 1;
 		}
 	}
 	if (clock_monotonic) {
 		nano = mach_absolute_time();
 		if ((info.denom != 1 || info.numer != 1) && factor != 0.0)
 			nano *= factor;
 		tp->tv_sec = nano / NSEC_PER_SEC;
 		rem = nano % NSEC_PER_SEC;
 		if (rem < 0) {
 			tp->tv_sec--;
 			rem += NSEC_PER_SEC;
 		}
 		tp->tv_usec = rem / 1000;
 		return 0;
 	}
 #endif

 	/* Something above failed, so fall back to gettimeofday */
 	if (!posix_clock_set) {
 		syslog(LOG_WARNING, NO_MONOTONIC);
 		posix_clock_set = 1;
 	}
 	return gettimeofday(tp, NULL);
 }

 ssize_t
 setvar(char ***e, const char *prefix, const char *var, const char *value)
 {
 	size_t len = strlen(var) + strlen(value) + 3;

 	if (prefix)
 		len += strlen(prefix) + 1;
 	**e = xmalloc(len);
 	if (prefix)
 		snprintf(**e, len, "%s_%s=%s", prefix, var, value);
 	else
 		snprintf(**e, len, "%s=%s", var, value);
 	(*e)++;
 	return len;
 }

 ssize_t
 setvard(char ***e, const char *prefix, const char *var, int value)
 {
 	char buffer[32];

 	snprintf(buffer, sizeof(buffer), "%d", value);
 	return setvar(e, prefix, var, buffer);
 }


 time_t
 uptime(void)
 {
 	struct timeval tv;

 	if (get_monotonic(&tv) == -1)
 		return -1;
 	return tv.tv_sec;
 }

 int
 writepid(int fd, pid_t pid)
 {
 	char spid[16];
 	ssize_t len;

 	if (ftruncate(fd, (off_t)0) == -1)
 		return -1;
 	snprintf(spid, sizeof(spid), "%u\n", pid);
 	len = pwrite(fd, spid, strlen(spid), (off_t)0);
 	if (len != (ssize_t)strlen(spid))
 		return -1;
 	return 0;
 }

 void *
 xmalloc(size_t s)
 {
 	void *value = malloc(s);

 	if (value != NULL)
 		return value;
 	syslog(LOG_ERR, "memory exhausted (xalloc %zu bytes)", s);
 	exit (EXIT_FAILURE);
 	/* NOTREACHED */
 }

 void *
 xzalloc(size_t s)
 {
 	void *value = xmalloc(s);

 	memset(value, 0, s);
 	return value;
 }

 void *
 xrealloc(void *ptr, size_t s)
 {
 	void *value = realloc(ptr, s);

 	if (value != NULL)
 		return value;
 	syslog(LOG_ERR, "memory exhausted (xrealloc %zu bytes)", s);
 	exit(EXIT_FAILURE);
 	/* NOTREACHED */
 }

 char *
 xstrdup(const char *str)
 {
 	char *value;

 	if (str == NULL)
 		return NULL;

 	if ((value = strdup(str)) != NULL)
 		return value;

 	syslog(LOG_ERR, "memory exhausted (xstrdup)");
 	exit(EXIT_FAILURE);
 	/* NOTREACHED */
 }
	/*
	* dhcpcd - DHCP client daemon
	* Copyright (c) 2006-2012 Roy Marples <roy@marples.name>
	* All rights reserved

	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	/* Needed define to get at getline for glibc and FreeBSD */
	#ifndef _GNU_SOURCE
	# define _GNU_SOURCE
	#endif

	#include <sys/cdefs.h>

	#ifdef __APPLE__
	# include <mach/mach_time.h>
	# include <mach/kern_return.h>
	#endif

	#include <sys/param.h>
	#include <sys/time.h>

	#include <errno.h>
	#include <fcntl.h>
	#include <limits.h>
	#ifdef BSD
	# include <paths.h>
	#endif
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <syslog.h>
	#include <time.h>
	#include <unistd.h>

	#include "common.h"

	#ifndef _PATH_DEVNULL
	# define _PATH_DEVNULL "/dev/null"
	#endif

	int clock_monotonic;
	static char *lbuf;
	static size_t lbuf_len;
	#ifdef DEBUG_MEMORY
	static char lbuf_set;
	#endif

	#ifdef DEBUG_MEMORY
	static void
	free_lbuf(void)
	{
	free(lbuf);
	lbuf = NULL;
	}
	#endif

	/* Handy routine to read very long lines in text files.
	* This means we read the whole line and avoid any nasty buffer overflows.
	* We strip leading space and avoid comment lines, making the code that calls
	* us smaller.
	* As we don't use threads, this API is clean too. */
	char *
	get_line(FILE * __restrict fp)
	{
	char *p;
	ssize_t bytes;

	#ifdef DEBUG_MEMORY
	if (lbuf_set == 0) {
	atexit(free_lbuf);
	lbuf_set = 1;
	}
	#endif

	do {
	bytes = getline(&lbuf, &lbuf_len, fp);
	if (bytes == -1)
	return NULL;
	for (p = lbuf; p == ' ' \|\| p == '\t'; p++)
	;
	} while (p == '\0' \|\| p == '\n' \|\| p == '#' \|\| p == ';');
	if (lbuf[--bytes] == '\n')
	lbuf[bytes] = '\0';
	return p;
	}

	int
	set_cloexec(int fd)
	{
	int flags;

	if ((flags = fcntl(fd, F_GETFD, 0)) == -1 \|\|
	fcntl(fd, F_SETFD, flags \| FD_CLOEXEC) == -1)
	{
	syslog(LOG_ERR, "fcntl: %m");
	return -1;
	}
	return 0;
	}

	int
	set_nonblock(int fd)
	{
	int flags;

	if ((flags = fcntl(fd, F_GETFL, 0)) == -1 \|\|
	fcntl(fd, F_SETFL, flags \| O_NONBLOCK) == -1)
	{
	syslog(LOG_ERR, "fcntl: %m");
	return -1;
	}
	return 0;
	}

	/* Handy function to get the time.
	* We only care about time advancements, not the actual time itself
	* Which is why we use CLOCK_MONOTONIC, but it is not available on all
	* platforms.
	*/
	#define NO_MONOTONIC "host does not support a monotonic clock - timing can skew"
	int
	get_monotonic(struct timeval *tp)
	{
	static int posix_clock_set = 0;
	#if defined(_POSIX_MONOTONIC_CLOCK) && defined(CLOCK_MONOTONIC)
	struct timespec ts;
	static clockid_t posix_clock;

	if (!posix_clock_set) {
	if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
	posix_clock = CLOCK_MONOTONIC;
	clock_monotonic = posix_clock_set = 1;
	}
	}

	if (clock_monotonic) {
	if (clock_gettime(posix_clock, &ts) == 0) {
	tp->tv_sec = ts.tv_sec;
	tp->tv_usec = ts.tv_nsec / 1000;
	return 0;
	}
	}
	#elif defined(__APPLE__)
	#define NSEC_PER_SEC 1000000000
	/* We can use mach kernel functions here.
	* This is crap though - why can't they implement clock_gettime?*/
	static struct mach_timebase_info info = { 0, 0 };
	static double factor = 0.0;
	uint64_t nano;
	long rem;

	if (!posix_clock_set) {
	if (mach_timebase_info(&info) == KERN_SUCCESS) {
	factor = (double)info.numer / (double)info.denom;
	clock_monotonic = posix_clock_set = 1;
	}
	}
	if (clock_monotonic) {
	nano = mach_absolute_time();
	if ((info.denom != 1 \|\| info.numer != 1) && factor != 0.0)
	nano *= factor;
	tp->tv_sec = nano / NSEC_PER_SEC;
	rem = nano % NSEC_PER_SEC;
	if (rem < 0) {
	tp->tv_sec--;
	rem += NSEC_PER_SEC;
	}
	tp->tv_usec = rem / 1000;
	return 0;
	}
	#endif

	/* Something above failed, so fall back to gettimeofday */
	if (!posix_clock_set) {
	syslog(LOG_WARNING, NO_MONOTONIC);
	posix_clock_set = 1;
	}
	return gettimeofday(tp, NULL);
	}

	ssize_t
	setvar(char **e, const char prefix, const char var, const char value)
	{
	size_t len = strlen(var) + strlen(value) + 3;

	if (prefix)
	len += strlen(prefix) + 1;
	**e = xmalloc(len);
	if (prefix)
	snprintf(**e, len, "%s_%s=%s", prefix, var, value);
	else
	snprintf(**e, len, "%s=%s", var, value);
	(*e)++;
	return len;
	}

	ssize_t
	setvard(char **e, const char prefix, const char *var, int value)
	{
	char buffer[32];

	snprintf(buffer, sizeof(buffer), "%d", value);
	return setvar(e, prefix, var, buffer);
	}


	time_t
	uptime(void)
	{
	struct timeval tv;

	if (get_monotonic(&tv) == -1)
	return -1;
	return tv.tv_sec;
	}

	int
	writepid(int fd, pid_t pid)
	{
	char spid[16];
	ssize_t len;

	if (ftruncate(fd, (off_t)0) == -1)
	return -1;
	snprintf(spid, sizeof(spid), "%u\n", pid);
	len = pwrite(fd, spid, strlen(spid), (off_t)0);
	if (len != (ssize_t)strlen(spid))
	return -1;
	return 0;
	}

	void *
	xmalloc(size_t s)
	{
	void *value = malloc(s);

	if (value != NULL)
	return value;
	syslog(LOG_ERR, "memory exhausted (xalloc %zu bytes)", s);
	exit (EXIT_FAILURE);
	/* NOTREACHED */
	}

	void *
	xzalloc(size_t s)
	{
	void *value = xmalloc(s);

	memset(value, 0, s);
	return value;
	}

	void *
	xrealloc(void *ptr, size_t s)
	{
	void *value = realloc(ptr, s);

	if (value != NULL)
	return value;
	syslog(LOG_ERR, "memory exhausted (xrealloc %zu bytes)", s);
	exit(EXIT_FAILURE);
	/* NOTREACHED */
	}

	char *
	xstrdup(const char *str)
	{
	char *value;

	if (str == NULL)
	return NULL;

	if ((value = strdup(str)) != NULL)
	return value;

	syslog(LOG_ERR, "memory exhausted (xstrdup)");
	exit(EXIT_FAILURE);
	/* NOTREACHED */
	}