update to 8.1.25RC1

add internal UTC if tzdata is missing

1 files changed, 746 insertions, 0 deletions

diff --git a/php-8.1.0-systzdata-v24.patch b/php-8.1.0-systzdata-v24.patch
new file mode 100644
index 0000000..ca6e634
--- /dev/null
+++ b/php-8.1.0-systzdata-v24.patch
@@ -0,0 +1,746 @@
+# License: MIT
+# http://opensource.org/licenses/MIT
+
+Add support for use of the system timezone database, rather
+than embedding a copy.  Discussed upstream but was not desired.
+
+History:
+f24: add internal UTC if tzdata is missing
+r23: fix possible buffer overflow
+r22: retrieve tzdata version from /usr/share/zoneinfo/tzdata.zi
+r21: adapt for timelib 2021.03 (in 8.1.0)
+r20: adapt for timelib 2020.03 (in 8.0.10RC1)
+r19: adapt for timelib 2020.02 (in 8.0.0beta2)
+r18: adapt for autotool change in 7.3.3RC1
+r17: adapt for timelib 2018.01 (in 7.3.2RC1)
+r16: adapt for timelib 2017.06 (in 7.2.3RC1)
+r15: adapt for timelib 2017.05beta7 (in 7.2.0RC1)
+r14: improve check for valid tz file
+r13: adapt for upstream changes to use PHP allocator
+r12: adapt for upstream changes for new zic
+r11: use canonical names to avoid more case sensitivity issues
+     round lat/long from zone.tab towards zero per builtin db
+r10: make timezone case insensitive
+r9: fix another compile error without --with-system-tzdata configured (Michael Heimpold)
+r8: fix compile error without --with-system-tzdata configured
+r7: improve check for valid timezone id to exclude directories
+r6: fix fd leak in r5, fix country code/BC flag use in
+    timezone_identifiers_list() using system db,
+    fix use of PECL timezonedb to override system db,
+r5: reverts addition of "System/Localtime" fake tzname.
+    updated for 5.3.0, parses zone.tab to pick up mapping between
+    timezone name, country code and long/lat coords
+r4: added "System/Localtime" tzname which uses /etc/localtime
+r3: fix a crash if /usr/share/zoneinfo doesn't exist (Raphael Geissert)
+r2: add filesystem trawl to set up name alias index
+r1: initial revision
+
+
+diff --git a/ext/date/config0.m4 b/ext/date/config0.m4
+index 6b803bf33e..53c3cdb3f4 100644
+--- a/ext/date/config0.m4
++++ b/ext/date/config0.m4
+@@ -4,6 +4,19 @@ AC_CHECK_HEADERS([io.h])
+ dnl Check for strtoll, atoll
+ AC_CHECK_FUNCS(strtoll atoll)
+ 
++PHP_ARG_WITH(system-tzdata, for use of system timezone data,
++[  --with-system-tzdata[=DIR]      to specify use of system timezone data],
++no, no)
++
++if test "$PHP_SYSTEM_TZDATA" != "no"; then
++   AC_DEFINE(HAVE_SYSTEM_TZDATA, 1, [Define if system timezone data is used])
++
++   if test "$PHP_SYSTEM_TZDATA" != "yes"; then
++      AC_DEFINE_UNQUOTED(HAVE_SYSTEM_TZDATA_PREFIX, "$PHP_SYSTEM_TZDATA",
++                         [Define for location of system timezone data])
++   fi
++fi
++
+ PHP_DATE_CFLAGS="-Wno-implicit-fallthrough -I@ext_builddir@/lib -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1 -DHAVE_TIMELIB_CONFIG_H=1"
+ timelib_sources="lib/astro.c lib/dow.c lib/parse_date.c lib/parse_tz.c lib/parse_posix.c
+                  lib/timelib.c lib/tm2unixtime.c lib/unixtime2tm.c lib/parse_iso_intervals.c lib/interval.c"
+diff --git a/ext/date/lib/parse_tz.c b/ext/date/lib/parse_tz.c
+index c7f93580d7..ec196a98b6 100644
+--- a/ext/date/lib/parse_tz.c
++++ b/ext/date/lib/parse_tz.c
+@@ -26,9 +26,33 @@
+ #include "timelib.h"
+ #include "timelib_private.h"
+ 
++#ifdef HAVE_SYSTEM_TZDATA
++#include <sys/mman.h>
++#include <sys/stat.h>
++#include <limits.h>
++#include <fcntl.h>
++#include <unistd.h>
++
++#include "php_scandir.h"
++
++static const unsigned char internal_utc[] = {
++        0x54, 0x5a, 0x69, 0x66, 0x32, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
++        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
++        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00,
++        0x00, 0x00, 0x55, 0x54, 0x43, 0x00, 0x54, 0x5a, 0x69, 0x66, 0x32, 0x00, 0x00, 0x00, 0x00, 0x00,
++        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
++        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00,
++        0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0x54, 0x43, 0x00, 0x0a, 0x55, 0x54, 0x43,
++        0x30, 0x0a
++};
++
++#else
+ #define TIMELIB_SUPPORTS_V2DATA
+ #define TIMELIB_SUPPORT_SLIM_FILE
+ #include "timezonedb.h"
++#endif
++
++#include <ctype.h>
+ 
+ #if (defined(__APPLE__) || defined(__APPLE_CC__)) && (defined(__BIG_ENDIAN__) || defined(__LITTLE_ENDIAN__))
+ # if defined(__LITTLE_ENDIAN__)
+@@ -95,6 +119,11 @@ static int read_php_preamble(const unsigned char **tzf, timelib_tzinfo *tz)
+ {
+ 	uint32_t version;
+ 
++	if (memcmp(*tzf, "TZif", 4) == 0) {
++		*tzf += 20;
++		return 0;
++	}
++
+ 	/* read ID */
+ 	version = (*tzf)[3] - '0';
+ 	*tzf += 4;
+@@ -577,7 +606,475 @@ void timelib_dump_tzinfo(timelib_tzinfo *tz)
+ 	}
+ }
+ 
+-static int seek_to_tz_position(const unsigned char **tzf, const char *timezone, const timelib_tzdb *tzdb)
++#ifdef HAVE_SYSTEM_TZDATA
++
++#ifdef HAVE_SYSTEM_TZDATA_PREFIX
++#define ZONEINFO_PREFIX HAVE_SYSTEM_TZDATA_PREFIX
++#else
++#define ZONEINFO_PREFIX "/usr/share/zoneinfo"
++#endif
++
++/* System timezone database pointer. */
++static const timelib_tzdb *timezonedb_system;
++
++/* Hash table entry for the cache of the zone.tab mapping table. */
++struct location_info {
++        char code[2];
++        double latitude, longitude;
++        char name[64];
++        char *comment;
++        struct location_info *next;
++};
++
++/* Cache of zone.tab. */
++static struct location_info **system_location_table;
++
++/* Size of the zone.tab hash table; a random-ish prime big enough to
++ * prevent too many collisions. */
++#define LOCINFO_HASH_SIZE (1021)
++
++/* Compute a case insensitive hash of str */
++static uint32_t tz_hash(const char *str)
++{
++    const unsigned char *p = (const unsigned char *)str;
++    uint32_t hash = 5381;
++    int c;
++
++    while ((c = tolower(*p++)) != '\0') {
++        hash = (hash << 5) ^ hash ^ c;
++    }
++
++    return hash % LOCINFO_HASH_SIZE;
++}
++
++/* Parse an ISO-6709 date as used in zone.tab. Returns end of the
++ * parsed string on success, or NULL on parse error.  On success,
++ * writes the parsed number to *result. */
++static char *parse_iso6709(char *p, double *result)
++{
++    double v, sign;
++    char *pend;
++    size_t len;
++
++    if (*p == '+')
++        sign = 1.0;
++    else if (*p == '-')
++        sign = -1.0;
++    else
++        return NULL;
++
++    p++;
++    for (pend = p; *pend >= '0' && *pend <= '9'; pend++)
++        ;;
++
++    /* Annoying encoding used by zone.tab has no decimal point, so use
++     * the length to determine the format:
++     * 
++     * 4 = DDMM
++     * 5 = DDDMM
++     * 6 = DDMMSS
++     * 7 = DDDMMSS
++     */
++    len = pend - p;
++    if (len < 4 || len > 7) {
++        return NULL;
++    }
++
++    /* p => [D]DD */
++    v = (p[0] - '0') * 10.0 + (p[1] - '0');
++    p += 2;
++    if (len == 5 || len == 7)
++        v = v * 10.0 + (*p++ - '0');
++    /* p => MM[SS] */
++    v += (10.0 * (p[0] - '0')
++          + p[1] - '0') / 60.0;
++    p += 2;
++    /* p => [SS] */
++    if (len > 5) {
++        v += (10.0 * (p[0] - '0')
++              + p[1] - '0') / 3600.0;
++        p += 2;
++    }
++
++    /* Round to five decimal place, not because it's a good idea,
++     * but, because the builtin data uses rounded data, so, match
++     * that. */
++    *result = trunc(v * sign * 100000.0) / 100000.0;
++
++    return p;
++}
++
++/* This function parses the zone.tab file to build up the mapping of
++ * timezone to country code and geographic location, and returns a
++ * hash table.  The hash table is indexed by the function:
++ *
++ *   tz_hash(timezone-name)
++ */
++static struct location_info **create_location_table(void)
++{
++    struct location_info **li, *i;
++    char zone_tab[PATH_MAX];
++    char line[512];
++    FILE *fp;
++
++    strncpy(zone_tab, ZONEINFO_PREFIX "/zone.tab", sizeof zone_tab);
++
++    fp = fopen(zone_tab, "r");
++    if (!fp) {
++        return NULL;
++    }
++
++    li = calloc(LOCINFO_HASH_SIZE, sizeof *li);
++
++    while (fgets(line, sizeof line, fp)) {
++        char *p = line, *code, *name, *comment;
++        uint32_t hash;
++        double latitude, longitude;
++
++        while (isspace(*p))
++            p++;
++
++        if (*p == '#' || *p == '\0' || *p == '\n')
++            continue;
++        
++        if (!isalpha(p[0]) || !isalpha(p[1]) || p[2] != '\t')
++            continue;
++        
++        /* code => AA */
++        code = p;
++        p[2] = 0;
++        p += 3;
++
++        /* coords => [+-][D]DDMM[SS][+-][D]DDMM[SS] */
++        p = parse_iso6709(p, &latitude);
++        if (!p) {
++            continue;
++        }
++        p = parse_iso6709(p, &longitude);
++        if (!p) {
++            continue;
++        }
++
++        if (!p || *p != '\t') {
++            continue;
++        }
++
++        /* name = string */
++        name = ++p;
++        while (*p != '\t' && *p && *p != '\n')
++            p++;
++
++        *p++ = '\0';
++
++        /* comment = string */
++        comment = p;
++        while (*p != '\t' && *p && *p != '\n')
++            p++;
++
++        if (*p == '\n' || *p == '\t')
++            *p = '\0';
++        
++        hash = tz_hash(name);
++        i = malloc(sizeof *i);
++        memcpy(i->code, code, 2);
++        strncpy(i->name, name, sizeof i->name);
++        i->comment = strdup(comment);
++        i->longitude = longitude;
++        i->latitude = latitude;
++        i->next = li[hash];
++        li[hash] = i;
++        /* printf("%s [%u, %f, %f]\n", name, hash, latitude, longitude); */
++    }
++
++    fclose(fp);
++
++    return li;
++}
++
++/* Return location info from hash table, using given timezone name.
++ * Returns NULL if the name could not be found. */
++const struct location_info *find_zone_info(struct location_info **li, 
++                                           const char *name)
++{
++    uint32_t hash = tz_hash(name);
++    const struct location_info *l;
++
++    if (!li) {
++        return NULL;
++    }
++
++    for (l = li[hash]; l; l = l->next) {
++        if (timelib_strcasecmp(l->name, name) == 0)
++            return l;
++    }
++
++    return NULL;
++}    
++
++/* Filter out some non-tzdata files and the posix/right databases, if
++ * present. */
++static int index_filter(const struct dirent *ent)
++{
++	return strcmp(ent->d_name, ".") != 0
++		&& strcmp(ent->d_name, "..") != 0
++		&& strcmp(ent->d_name, "posix") != 0
++		&& strcmp(ent->d_name, "posixrules") != 0
++		&& strcmp(ent->d_name, "right") != 0
++		&& strstr(ent->d_name, ".list") == NULL
++		&& strstr(ent->d_name, ".tab") == NULL;
++}
++
++static int sysdbcmp(const void *first, const void *second)
++{
++        const timelib_tzdb_index_entry *alpha = first, *beta = second;
++
++        return timelib_strcasecmp(alpha->id, beta->id);
++}
++
++/* Retrieve tzdata version. */
++static void retrieve_zone_version(timelib_tzdb *db)
++{
++    static char buf[30];
++    char path[PATH_MAX];
++    FILE *fp;
++
++    strncpy(path, ZONEINFO_PREFIX "/tzdata.zi", sizeof(path));
++
++    fp = fopen(path, "r");
++    if (fp) {
++		if (fgets(buf, sizeof(buf), fp)) {
++			if (!memcmp(buf, "# version ", 10) &&
++				isdigit(buf[10]) &&
++				isdigit(buf[11]) &&
++				isdigit(buf[12]) &&
++				isdigit(buf[13]) &&
++				islower(buf[14])) {
++				if (buf[14] >= 't') {        /* 2022t = 2022.20 */
++					buf[17] = 0;
++					buf[16] = buf[14] - 't' + '0';
++					buf[15] = '2';
++				} else if (buf[14] >= 'j') { /* 2022j = 2022.10 */
++					buf[17] = 0;
++					buf[16] = buf[14] - 'j' + '0';
++					buf[15] = '1';
++				} else {                     /* 2022a = 2022.1  */
++					buf[16] = 0;
++					buf[15] = buf[14] - 'a' + '1';
++				}
++				buf[14] = '.';
++				db->version = buf+10;
++			}
++		}
++		fclose(fp);
++    }
++}
++
++
++/* Create the zone identifier index by trawling the filesystem. */
++static void create_zone_index(timelib_tzdb *db)
++{
++	size_t dirstack_size,  dirstack_top;
++	size_t index_size, index_next;
++	timelib_tzdb_index_entry *db_index;
++	char **dirstack;
++
++	/* LIFO stack to hold directory entries to scan; each slot is a
++	 * directory name relative to the zoneinfo prefix. */
++	dirstack_size = 32;
++	dirstack = malloc(dirstack_size * sizeof *dirstack);
++	dirstack_top = 1;
++	dirstack[0] = strdup("");
++	
++	/* Index array. */
++	index_size = 64;
++	db_index = malloc(index_size * sizeof *db_index);
++	index_next = 0;
++
++	do {
++		struct dirent **ents;
++		char name[PATH_MAX], *top;
++		int count;
++
++		/* Pop the top stack entry, and iterate through its contents. */
++		top = dirstack[--dirstack_top];
++		snprintf(name, sizeof name, ZONEINFO_PREFIX "/%s", top);
++
++		count = php_scandir(name, &ents, index_filter, php_alphasort);
++
++		while (count > 0) {
++			struct stat st;
++			const char *leaf = ents[count - 1]->d_name;
++
++			snprintf(name, sizeof name, ZONEINFO_PREFIX "/%s/%s", 
++				 top, leaf);
++			
++			if (strlen(name) && stat(name, &st) == 0) {
++				/* Name, relative to the zoneinfo prefix. */
++				const char *root = top;
++
++				if (root[0] == '/') root++;
++
++				snprintf(name, sizeof name, "%s%s%s", root, 
++					 *root ? "/": "", leaf);
++
++				if (S_ISDIR(st.st_mode)) {
++					if (dirstack_top == dirstack_size) {
++						dirstack_size *= 2;
++						dirstack = realloc(dirstack, 
++								   dirstack_size * sizeof *dirstack);
++					}
++					dirstack[dirstack_top++] = strdup(name);
++				}
++				else {
++					if (index_next == index_size) {
++						index_size *= 2;
++						db_index = realloc(db_index,
++								   index_size * sizeof *db_index);
++					}
++
++					db_index[index_next++].id = strdup(name);
++				}
++			}
++
++			free(ents[--count]);
++		}
++		
++		if (count != -1) free(ents);
++		free(top);
++	} while (dirstack_top);
++
++        qsort(db_index, index_next, sizeof *db_index, sysdbcmp);
++
++	if (!index_next) {
++		db_index[index_next++].id = strdup("UTC");
++	}
++	db->index = db_index;
++	db->index_size = index_next;
++
++	free(dirstack);
++}
++
++#define FAKE_HEADER "1234\0??\1??"
++#define FAKE_UTC_POS (7 - 4)
++
++/* Create a fake data segment for database 'sysdb'. */
++static void fake_data_segment(timelib_tzdb *sysdb,
++                              struct location_info **info)
++{
++        size_t n;
++        char *data, *p;
++        
++        data = malloc(3 * sysdb->index_size + sizeof(FAKE_HEADER) - 1);
++
++        p = mempcpy(data, FAKE_HEADER, sizeof(FAKE_HEADER) - 1);
++
++        for (n = 0; n < sysdb->index_size; n++) {
++                const struct location_info *li;
++                timelib_tzdb_index_entry *ent;
++
++                ent = (timelib_tzdb_index_entry *)&sysdb->index[n];
++
++                /* Lookup the timezone name in the hash table. */
++                if (strcmp(ent->id, "UTC") == 0) {
++                        ent->pos = FAKE_UTC_POS;
++                        continue;
++                }
++
++                li = find_zone_info(info, ent->id);
++                if (li) {
++                        /* If found, append the BC byte and the
++                         * country code; set the position for this
++                         * section of timezone data.  */
++                        ent->pos = (p - data) - 4;
++                        *p++ = '\1';
++                        *p++ = li->code[0];
++                        *p++ = li->code[1];
++                }
++                else {
++                        /* If not found, the timezone data can
++                         * point at the header. */
++                        ent->pos = 0;
++                }
++        }
++        
++        sysdb->data = (unsigned char *)data;
++}
++
++/* Returns true if the passed-in stat structure describes a
++ * probably-valid timezone file. */
++static int is_valid_tzfile(const struct stat *st, int fd)
++{
++	if (fd) {
++		char buf[20];
++		if (read(fd, buf, 20)!=20) {
++			return 0;
++		}
++		lseek(fd, SEEK_SET, 0);
++		if (memcmp(buf, "TZif", 4)) {
++			return 0;
++		}
++	}
++	return S_ISREG(st->st_mode) && st->st_size > 20;
++}
++
++/* To allow timezone names to be used case-insensitively, find the
++ * canonical name for this timezone, if possible. */
++static const char *canonical_tzname(const char *timezone)
++{
++    if (timezonedb_system) {
++        timelib_tzdb_index_entry *ent, lookup;
++
++        lookup.id = (char *)timezone;
++
++        ent = bsearch(&lookup, timezonedb_system->index,
++                      timezonedb_system->index_size, sizeof lookup,
++                      sysdbcmp);
++        if (ent) {
++            return ent->id;
++        }
++    }
++
++    return timezone;
++}
++
++/* Return the mmap()ed tzfile if found, else NULL.  On success, the
++ * length of the mapped data is placed in *length. */
++static char *map_tzfile(const char *timezone, size_t *length)
++{
++	char fname[PATH_MAX];
++	struct stat st;
++	char *p;
++	int fd;
++	
++	if (timezone[0] == '\0' || strstr(timezone, "..") != NULL) {
++		return NULL;
++	}
++
++	snprintf(fname, sizeof fname, ZONEINFO_PREFIX "/%s", canonical_tzname(timezone));
++
++	fd = open(fname, O_RDONLY);
++	if (fd == -1) {
++		if (strcmp(timezone, "UTC")) {
++			return NULL;
++		} else {
++			*length = sizeof(internal_utc);
++			return internal_utc;
++		}
++	} else if (fstat(fd, &st) != 0 || !is_valid_tzfile(&st, fd)) {
++		close(fd);
++		return NULL;
++	}
++
++	*length = st.st_size;
++	p = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
++	close(fd);
++	
++	return p != MAP_FAILED ? p : NULL;
++}
++
++#endif
++
++static int inmem_seek_to_tz_position(const unsigned char **tzf, const char *timezone, const timelib_tzdb *tzdb)
+ {
+ 	int left = 0, right = tzdb->index_size - 1;
+ 
+@@ -603,9 +1100,49 @@ static int seek_to_tz_position(const unsigned char **tzf, const char *timezone,
+ 	return 0;
+ }
+ 
++static int seek_to_tz_position(const unsigned char **tzf, const char *timezone,
++			       char **map, size_t *maplen,
++			       const timelib_tzdb *tzdb)
++{
++#ifdef HAVE_SYSTEM_TZDATA
++	if (tzdb == timezonedb_system) {
++		char *orig;
++
++		orig = map_tzfile(timezone, maplen);
++		if (orig == NULL) {
++			return 0;
++		}
++
++		(*tzf) = (unsigned char *)orig;
++		*map = orig;
++        return 1;
++	}
++	else
++#endif
++	{
++		return inmem_seek_to_tz_position(tzf, timezone, tzdb);
++	}
++}
++
+ const timelib_tzdb *timelib_builtin_db(void)
+ {
++#ifdef HAVE_SYSTEM_TZDATA
++	if (timezonedb_system == NULL) {
++		timelib_tzdb *tmp = malloc(sizeof *tmp);
++
++		tmp->version = "0";
++		tmp->data = NULL;
++		create_zone_index(tmp);
++		retrieve_zone_version(tmp);
++		system_location_table = create_location_table();
++		fake_data_segment(tmp, system_location_table);
++		timezonedb_system = tmp;
++	}
++
++	return timezonedb_system;
++#else
+ 	return &timezonedb_builtin;
++#endif
+ }
+ 
+ const timelib_tzdb_index_entry *timelib_timezone_identifiers_list(const timelib_tzdb *tzdb, int *count)
+@@ -617,7 +1154,32 @@ const timelib_tzdb_index_entry *timelib_timezone_identifiers_list(const timelib_
+ int timelib_timezone_id_is_valid(const char *timezone, const timelib_tzdb *tzdb)
+ {
+ 	const unsigned char *tzf;
+-	return (seek_to_tz_position(&tzf, timezone, tzdb));
++
++#ifdef HAVE_SYSTEM_TZDATA
++	if (tzdb == timezonedb_system) {
++		char fname[PATH_MAX];
++		struct stat st;
++
++		if (timezone[0] == '\0' || strstr(timezone, "..") != NULL) {
++			return 0;
++		}
++		if (!strcmp(timezone, "UTC")) {
++			return 1;
++		}
++		if (system_location_table) {
++			if (find_zone_info(system_location_table, timezone) != NULL) {
++				/* found in cache */
++				return 1;
++			}
++		}
++
++		snprintf(fname, sizeof fname, ZONEINFO_PREFIX "/%s", canonical_tzname(timezone));
++
++		return stat(fname, &st) == 0 && is_valid_tzfile(&st, 0);
++	}
++#endif
++
++	return (inmem_seek_to_tz_position(&tzf, timezone, tzdb));
+ }
+ 
+ static int skip_64bit_preamble(const unsigned char **tzf, timelib_tzinfo *tz)
+@@ -662,6 +1224,8 @@ static timelib_tzinfo* timelib_tzinfo_ctor(const char *name)
+ timelib_tzinfo *timelib_parse_tzfile(const char *timezone, const timelib_tzdb *tzdb, int *error_code)
+ {
+ 	const unsigned char *tzf;
++	char *memmap = NULL;
++	size_t maplen;
+ 	timelib_tzinfo *tmp;
+ 	int version;
+ 	int transitions_result, types_result;
+@@ -669,7 +1233,7 @@ timelib_tzinfo *timelib_parse_tzfile(const char *timezone, const timelib_tzdb *t
+ 
+ 	*error_code = TIMELIB_ERROR_NO_ERROR;
+ 
+-	if (seek_to_tz_position(&tzf, timezone, tzdb)) {
++	if (seek_to_tz_position(&tzf, timezone, &memmap, &maplen, tzdb)) {
+ 		tmp = timelib_tzinfo_ctor(timezone);
+ 
+ 		version = read_preamble(&tzf, tmp, &type);
+@@ -712,11 +1276,38 @@ timelib_tzinfo *timelib_parse_tzfile(const char *timezone, const timelib_tzdb *t
+ 			return NULL;
+ 		}
+ 
++#ifdef HAVE_SYSTEM_TZDATA
++		if (memmap) {
++			const struct location_info *li;
++
++			/* TZif-style - grok the location info from the system database,
++			 * if possible. */
++
++			if ((li = find_zone_info(system_location_table, timezone)) != NULL) {
++				tmp->location.comments = timelib_strdup(li->comment);
++				strncpy(tmp->location.country_code, li->code, 2);
++				tmp->location.longitude = li->longitude;
++				tmp->location.latitude = li->latitude;
++				tmp->bc = 1;
++			}
++			else {
++				set_default_location_and_comments(&tzf, tmp);
++			}
++
++			/* Now done with the mmap segment - discard it. */
++			if (memmap != internal_utc) {
++				munmap(memmap, maplen);
++			}
++		} else {
++#endif
+ 		if (type == TIMELIB_TZINFO_PHP) {
+ 			read_location(&tzf, tmp);
+ 		} else {
+ 			set_default_location_and_comments(&tzf, tmp);
+ 		}
++#ifdef HAVE_SYSTEM_TZDATA
++		}
++#endif
+ 	} else {
+ 		*error_code = TIMELIB_ERROR_NO_SUCH_TIMEZONE;
+ 		tmp = NULL;
+diff --git a/ext/date/php_date.c b/ext/date/php_date.c
+index 48c82bf7ec..443299c089 100644
+--- a/ext/date/php_date.c
++++ b/ext/date/php_date.c
+@@ -490,7 +490,11 @@ PHP_MINFO_FUNCTION(date)
+ 	php_info_print_table_row(2, "date/time support", "enabled");
+ 	php_info_print_table_row(2, "timelib version", TIMELIB_ASCII_VERSION);
+ 	php_info_print_table_row(2, "\"Olson\" Timezone Database Version", tzdb->version);
++#ifdef HAVE_SYSTEM_TZDATA
++	php_info_print_table_row(2, "Timezone Database", "system");
++#else
+ 	php_info_print_table_row(2, "Timezone Database", php_date_global_timezone_db_enabled ? "external" : "internal");
++#endif
+ 	php_info_print_table_row(2, "Default timezone", guess_timezone(tzdb));
+ 	php_info_print_table_end();
+