localtime.c

Asterisk-1.4.4最新内核源代码

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[e-mail]>
 *
 * Most of this code is in the public domain, so clarified as of
 * June 5, 1996 by Arthur David Olson ([e-mail]).
 *
 * All modifications to this code to abstract timezones away from
 * the environment are by Tilghman Lesher, <[e-mail]>, with
 * the copyright assigned to Digium.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * Multi-timezone Localtime code
 * 
 * \author Leap second handling Bradley White ([e-mail]).
 * \author POSIX-style TZ environment variable handling from Guy Harris ([e-mail]).
 *
 */

/*
 * Asterisk defines
 *
 * Don't mess with these unless you're really sure you know what you're doing.
 */
#ifndef _THREAD_SAFE
#define _THREAD_SAFE
#endif
#define TZ_STRLEN_MAX	255
/* #define DEBUG */

/*LINTLIBRARY*/

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef DEBUG
#include <stdio.h>
#endif

#include "private.h"
#include "tzfile.h"

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 51256 $")

#include "asterisk/lock.h"
#include "asterisk/localtime.h"
#include "asterisk/strings.h"

#ifndef lint
#ifndef NOID
static const char elsieid[] = "@(#)localtime.c	7.57";
#endif /* !defined NOID */
#endif /* !defined lint */



/*
** SunOS 4.1.1 headers lack O_BINARY.
*/

#ifdef O_BINARY
#define OPEN_MODE	(O_RDONLY | O_BINARY)
#endif /* defined O_BINARY */
#ifndef O_BINARY
#define OPEN_MODE	O_RDONLY
#endif /* !defined O_BINARY */

#ifdef SOLARIS
#undef TM_ZONE
#undef TM_GMTOFF 
#endif

#ifdef TM_ZONE
#ifndef WILDABBR
/*! \note
 * Someone might make incorrect use of a time zone abbreviation:
 *	1.	They might reference tzname[0] before calling ast_tzset (explicitly
 *		or implicitly).
 *	2.	They might reference tzname[1] before calling ast_tzset (explicitly
 *		or implicitly).
 *	3.	They might reference tzname[1] after setting to a time zone
 *		in which Daylight Saving Time is never observed.
 *	4.	They might reference tzname[0] after setting to a time zone
 *		in which Standard Time is never observed.
 *	5.	They might reference tm.TM_ZONE after calling offtime.
 * What's best to do in the above cases is open to debate;
 * for now, we just set things up so that in any of the five cases
 * WILDABBR is used.  Another possibility:  initialize tzname[0] to the
 * string "tzname[0] used before set", and similarly for the other cases.
 * And another:  initialize tzname[0] to "ERA", with an explanation in the
 * manual page of what this "time zone abbreviation" means (doing this so
 * that tzname[0] has the "normal" length of three characters).
 */
#define WILDABBR	"   "
#endif /* !defined WILDABBR */

static char		wildabbr[] = "WILDABBR";
#endif /* TM_ZONE */

/*! \brief FreeBSD defines 'zone' in 'struct tm' as non-const, so don't declare this
   string as const. */
static char		gmt[] = "GMT";

/*!< \brief time type information */
struct ttinfo {
	long		tt_gmtoff;	/*!< GMT offset in seconds */
	int		tt_isdst;	/*!< used to set tm_isdst */
	int		tt_abbrind;	/*!< abbreviation list index */
	int		tt_ttisstd;	/*!< TRUE if transition is std time */
	int		tt_ttisgmt;	/*!< TRUE if transition is GMT */
};

/*! \brief leap second information */
struct lsinfo {
	time_t		ls_trans;	/*!< transition time */
	long		ls_corr;	/*!< correction to apply */
};

#define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))

#ifdef TZNAME_MAX
#define MY_TZNAME_MAX	TZNAME_MAX
#endif /* defined TZNAME_MAX */
#ifndef TZNAME_MAX
#define MY_TZNAME_MAX	255
#endif /* !defined TZNAME_MAX */

struct state {
	char	name[TZ_STRLEN_MAX + 1];
	int		leapcnt;
	int		timecnt;
	int		typecnt;
	int		charcnt;
	time_t		ats[TZ_MAX_TIMES];
	unsigned char	types[TZ_MAX_TIMES];
	struct ttinfo	ttis[TZ_MAX_TYPES];
	char		chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
				(2 * (MY_TZNAME_MAX + 1)))];
	struct lsinfo	lsis[TZ_MAX_LEAPS];
	struct state	*next;
};

struct rule {
	int		r_type;		/*!< type of rule--see below */
	int		r_day;		/*!< day number of rule */
	int		r_week;		/*!< week number of rule */
	int		r_mon;		/*!< month number of rule */
	long		r_time;		/*!< transition time of rule */
};

#define JULIAN_DAY		0	/*!< Jn - Julian day */
#define DAY_OF_YEAR		1	/*!< n - day of year */
#define MONTH_NTH_DAY_OF_WEEK	2	/*!< Mm.n.d - month, week, day of week */

/*
** Prototypes for static functions.
*/

static long		detzcode P((const char * codep));
static const char *	getnum P((const char * strp, int * nump, int min,
				int max));
static const char *	getsecs P((const char * strp, long * secsp));
static const char *	getoffset P((const char * strp, long * offsetp));
static const char *	getrule P((const char * strp, struct rule * rulep));
static void		gmtload P((struct state * sp));
static void		gmtsub P((const time_t * timep, long offset,
				struct tm * tmp, const char * zone));
static void		localsub P((const time_t * timep, long offset,
				struct tm * tmp, const char * zone));
static int		increment_overflow P((int * number, int delta));
static int		normalize_overflow P((int * tensptr, int * unitsptr,
				int base));
static time_t		time1 P((struct tm * tmp,
				void(*funcp) P((const time_t *,
				long, struct tm *, const char*)),
				long offset, const char * zone));
static time_t		time2 P((struct tm *tmp,
				void(*funcp) P((const time_t *,
				long, struct tm*, const char*)),
				long offset, int * okayp, const char * zone));
static void		timesub P((const time_t * timep, long offset,
				const struct state * sp, struct tm * tmp));
static int		tmcomp P((const struct tm * atmp,
				const struct tm * btmp));
static time_t		transtime P((time_t janfirst, int year,
				const struct rule * rulep, long offset));
static int		tzload P((const char * name, struct state * sp));
static int		tzparse P((const char * name, struct state * sp,
				int lastditch));

static struct state *	lclptr      = NULL;
static struct state *	last_lclptr = NULL;
static struct state *	gmtptr      = NULL;

#ifndef TZ_STRLEN_MAX
#define TZ_STRLEN_MAX 255
#endif /* !defined TZ_STRLEN_MAX */

static int		gmt_is_set;
#ifdef	_THREAD_SAFE
AST_MUTEX_DEFINE_STATIC(lcl_mutex);
AST_MUTEX_DEFINE_STATIC(tzset_mutex);
AST_MUTEX_DEFINE_STATIC(tzsetwall_mutex);
AST_MUTEX_DEFINE_STATIC(gmt_mutex);
#endif

/*
** Section 4.12.3 of X3.159-1989 requires that
**	Except for the strftime function, these functions [asctime,
**	ctime, gmtime, localtime] return values in one of two static
**	objects: a broken-down time structure and an array of char.
** Thanks to Paul Eggert ([e-mail]) for noting this.
*/

static long detzcode(const char * const	codep)
{
	register long	result;
	register int	i;

	result = (codep[0] & 0x80) ? ~0L : 0L;
	for (i = 0; i < 4; ++i)
		result = (result << 8) | (codep[i] & 0xff);
	return result;
}

static int tzload(register const char *name, register struct state *const	sp)
{
	register const char *	p;
	register int		i;
	register int		fid;

#ifdef DEBUG
	fprintf(stderr,"tzload called with name=%s, sp=%d\n", name, sp);
#endif
	if (name == NULL && (name = TZDEFAULT) == NULL)
		return -1;
	{
		register int	doaccess;
		struct stat	stab;
		/*
		** Section 4.9.1 of the C standard says that
		** "FILENAME_MAX expands to an integral constant expression
		** that is the size needed for an array of char large enough
		** to hold the longest file name string that the implementation
		** guarantees can be opened."
		*/
		char		fullname[FILENAME_MAX + 1] = "";

		if (name[0] == ':')
			++name;
		doaccess = name[0] == '/';
		if (!doaccess) {
			if ((p = TZDIR) == NULL)
				return -1;
			if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
				return -1;
			(void) strncpy(fullname, p, sizeof(fullname) - 1);
			(void) strncat(fullname, "/", sizeof(fullname) - strlen(fullname) - 1);
			(void) strncat(fullname, name, sizeof(fullname) - strlen(fullname) - 1);
			/*
			** Set doaccess if '.' (as in "../") shows up in name.
			*/
			if (strchr(name, '.') != NULL)
				doaccess = TRUE;
			name = fullname;
		}
		if (doaccess && access(name, R_OK) != 0)
		     	return -1;
		if ((fid = open(name, OPEN_MODE)) == -1)
			return -1;
		if ((fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
			close(fid);
			return -1;
		}
	}
	{
		struct tzhead *	tzhp;
		char		buf[sizeof *sp + sizeof *tzhp];
		int		ttisstdcnt;
		int		ttisgmtcnt;

		i = read(fid, buf, sizeof buf);
		if (close(fid) != 0)
			return -1;
		p = buf;
		p += (sizeof tzhp->tzh_magic) + (sizeof tzhp->tzh_reserved);
		ttisstdcnt = (int) detzcode(p);
		p += 4;
		ttisgmtcnt = (int) detzcode(p);
		p += 4;
		sp->leapcnt = (int) detzcode(p);
		p += 4;
		sp->timecnt = (int) detzcode(p);
		p += 4;
		sp->typecnt = (int) detzcode(p);
		p += 4;
		sp->charcnt = (int) detzcode(p);
		p += 4;
		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
				return -1;
		if (i - (p - buf) < sp->timecnt * 4 +	/* ats */
			sp->timecnt +			/* types */
			sp->typecnt * (4 + 2) +		/* ttinfos */
			sp->charcnt +			/* chars */
			sp->leapcnt * (4 + 4) +		/* lsinfos */
			ttisstdcnt +			/* ttisstds */
			ttisgmtcnt)			/* ttisgmts */
				return -1;
		for (i = 0; i < sp->timecnt; ++i) {
			sp->ats[i] = detzcode(p);
			p += 4;
		}
		for (i = 0; i < sp->timecnt; ++i) {
			sp->types[i] = (unsigned char) *p++;
			if (sp->types[i] >= sp->typecnt)
				return -1;
		}
		for (i = 0; i < sp->typecnt; ++i) {
			register struct ttinfo *	ttisp;

			ttisp = &sp->ttis[i];
			ttisp->tt_gmtoff = detzcode(p);
			p += 4;
			ttisp->tt_isdst = (unsigned char) *p++;
			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
				return -1;
			ttisp->tt_abbrind = (unsigned char) *p++;
			if (ttisp->tt_abbrind < 0 ||
				ttisp->tt_abbrind > sp->charcnt)
					return -1;
		}
		for (i = 0; i < sp->charcnt; ++i)
			sp->chars[i] = *p++;
		sp->chars[i] = '\0';	/* ensure '\0' at end */
		for (i = 0; i < sp->leapcnt; ++i) {
			register struct lsinfo *	lsisp;

			lsisp = &sp->lsis[i];
			lsisp->ls_trans = detzcode(p);
			p += 4;
			lsisp->ls_corr = detzcode(p);
			p += 4;
		}
		for (i = 0; i < sp->typecnt; ++i) {
			register struct ttinfo *	ttisp;

			ttisp = &sp->ttis[i];
			if (ttisstdcnt == 0)
				ttisp->tt_ttisstd = FALSE;
			else {
				ttisp->tt_ttisstd = *p++;
				if (ttisp->tt_ttisstd != TRUE &&
					ttisp->tt_ttisstd != FALSE)
						return -1;
			}
		}
		for (i = 0; i < sp->typecnt; ++i) {
			register struct ttinfo *	ttisp;

			ttisp = &sp->ttis[i];
			if (ttisgmtcnt == 0)
				ttisp->tt_ttisgmt = FALSE;
			else {
				ttisp->tt_ttisgmt = *p++;
				if (ttisp->tt_ttisgmt != TRUE &&
					ttisp->tt_ttisgmt != FALSE)
						return -1;
			}
		}
	}
	return 0;
}

static const int	mon_lengths[2][MONSPERYEAR] = {
	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};

static const int	year_lengths[2] = {
	DAYSPERNYEAR, DAYSPERLYEAR
};

/*! \brief
 * Given a pointer into a time zone string, extract a number from that string.
 * \return Check that the number is within a specified range; if it is not, return
 * NULL.
 * Otherwise, return a pointer to the first character not part of the number.
*/

static const char *getnum(register const char *strp, int * const nump, const int min, const int max)
{
	register char	c;
	register int	num;

	if (strp == NULL || !is_digit(c = *strp))
		return NULL;
	num = 0;
	do {
		num = num * 10 + (c - '0');
		if (num > max)
			return NULL;	/* illegal value */
		c = *++strp;
	} while (is_digit(c));
	if (num < min)
		return NULL;		/* illegal value */
	*nump = num;
	return strp;
}

/*! \brief
 * Given a pointer into a time zone string, extract a number of seconds,
 * in hh[:mm[:ss]] form, from the string.
 * \return If any error occurs, return NULL.
 * Otherwise, return a pointer to the first character not part of the number
 * of seconds.
*/

static const char *getsecs(register const char *strp, long * const secsp)
{
	int	num;

	/*
	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
	** "M10.4.6/26", which does not conform to Posix,
	** but which specifies the equivalent of
	** ``02:00 on the first Sunday on or after 23 Oct''.
	*/
	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
	if (strp == NULL)
		return NULL;
	*secsp = num * (long) SECSPERHOUR;
	if (*strp == ':') {
		++strp;
		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
		if (strp == NULL)
			return NULL;
		*secsp += num * SECSPERMIN;
		if (*strp == ':') {
			++strp;
			/* `SECSPERMIN' allows for leap seconds.  */
			strp = getnum(strp, &num, 0, SECSPERMIN);
			if (strp == NULL)
				return NULL;
			*secsp += num;
		}
	}
	return strp;
}

/*! \brief
 * Given a pointer into a time zone string, extract an offset, in
 * [+-]hh[:mm[:ss]] form, from the string.
 * \return If any error occurs, return NULL.
 * Otherwise, return a pointer to the first character not part of the time.
*/

static const char * getoffset(register const char *strp, long * const offsetp)
{
	register int	neg = 0;

	if (*strp == '-') {
		neg = 1;
		++strp;
	} else if (*strp == '+')
		++strp;
	strp = getsecs(strp, offsetp);
	if (strp == NULL)
		return NULL;		/* illegal time */
	if (neg)
		*offsetp = -*offsetp;
	return strp;
}

/*! \brief
 * Given a pointer into a time zone string, extract a rule in the form
 * date[/time].  See POSIX section 8 for the format of "date" and "time".
 * \return If a valid rule is not found, return NULL.
 * Otherwise, return a pointer to the first character not part of the rule.
*/

static const char *getrule(const char *strp, register struct rule * const rulep)