640b76b7dc
2004-08-11 Ulrich Drepper <drepper@redhat.com> * time/tzset.c (tzset_internal): Add new parameter which is nonzero if called through tzset. Use TZDEFAULT name including name comparison if the new parameter is zero. This means implicit tzset calls will not cause files to be opened and read by tzfile.c all the time. 2004-08-11 Jakub Jelinek <jakub@redhat.com> * time/tzfile.c (__tzfile_read): Free transitions only if it will not be reused.
594 lines
16 KiB
C
594 lines
16 KiB
C
/* Copyright (C) 1991-1993,1995-2001,2003,2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdio_ext.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#define NOID
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#include <timezone/tzfile.h>
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int __use_tzfile;
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static dev_t tzfile_dev;
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static ino64_t tzfile_ino;
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struct ttinfo
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{
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long int offset; /* Seconds east of GMT. */
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unsigned char isdst; /* Used to set tm_isdst. */
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unsigned char idx; /* Index into `zone_names'. */
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unsigned char isstd; /* Transition times are in standard time. */
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unsigned char isgmt; /* Transition times are in GMT. */
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};
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struct leap
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{
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time_t transition; /* Time the transition takes effect. */
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long int change; /* Seconds of correction to apply. */
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};
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static struct ttinfo *find_transition (time_t timer) internal_function;
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static void compute_tzname_max (size_t) internal_function;
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static size_t num_transitions;
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libc_freeres_ptr (static time_t *transitions);
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static unsigned char *type_idxs;
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static size_t num_types;
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static struct ttinfo *types;
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static char *zone_names;
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static long int rule_stdoff;
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static long int rule_dstoff;
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static size_t num_leaps;
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static struct leap *leaps;
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#include <endian.h>
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#include <byteswap.h>
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/* Decode the four bytes at PTR as a signed integer in network byte order. */
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static inline int
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__attribute ((always_inline))
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decode (const void *ptr)
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{
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if ((BYTE_ORDER == BIG_ENDIAN) && sizeof (int) == 4)
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return *(const int *) ptr;
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else if (BYTE_ORDER == LITTLE_ENDIAN && sizeof (int) == 4)
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return bswap_32 (*(const int *) ptr);
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else
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{
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const unsigned char *p = ptr;
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int result = *p & (1 << (CHAR_BIT - 1)) ? ~0 : 0;
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result = (result << 8) | *p++;
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result = (result << 8) | *p++;
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result = (result << 8) | *p++;
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result = (result << 8) | *p++;
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return result;
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}
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}
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void
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__tzfile_read (const char *file, size_t extra, char **extrap)
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{
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static const char default_tzdir[] = TZDIR;
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size_t num_isstd, num_isgmt;
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register FILE *f;
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struct tzhead tzhead;
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size_t chars;
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register size_t i;
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size_t total_size;
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size_t types_idx;
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size_t leaps_idx;
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int was_using_tzfile = __use_tzfile;
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__use_tzfile = 0;
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if (file == NULL)
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/* No user specification; use the site-wide default. */
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file = TZDEFAULT;
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else if (*file == '\0')
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/* User specified the empty string; use UTC with no leap seconds. */
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goto ret_free_transitions;
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else
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{
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/* We must not allow to read an arbitrary file in a setuid
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program. So we fail for any file which is not in the
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directory hierachy starting at TZDIR
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and which is not the system wide default TZDEFAULT. */
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if (__libc_enable_secure
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&& ((*file == '/'
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&& memcmp (file, TZDEFAULT, sizeof TZDEFAULT)
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&& memcmp (file, default_tzdir, sizeof (default_tzdir) - 1))
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|| strstr (file, "../") != NULL))
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/* This test is certainly a bit too restrictive but it should
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catch all critical cases. */
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goto ret_free_transitions;
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}
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if (*file != '/')
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{
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const char *tzdir;
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unsigned int len, tzdir_len;
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char *new, *tmp;
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tzdir = getenv ("TZDIR");
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if (tzdir == NULL || *tzdir == '\0')
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{
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tzdir = default_tzdir;
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tzdir_len = sizeof (default_tzdir) - 1;
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}
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else
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tzdir_len = strlen (tzdir);
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len = strlen (file) + 1;
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new = (char *) __alloca (tzdir_len + 1 + len);
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tmp = __mempcpy (new, tzdir, tzdir_len);
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*tmp++ = '/';
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memcpy (tmp, file, len);
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file = new;
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}
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/* Note the file is opened with cancellation in the I/O functions
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disabled. */
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f = fopen (file, "rc");
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if (f == NULL)
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goto ret_free_transitions;
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/* Get information about the file. */
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struct stat64 st;
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if (fstat64 (fileno (f), &st) != 0)
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{
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fclose (f);
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goto ret_free_transitions;
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}
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if (was_using_tzfile && tzfile_ino == st.st_ino && tzfile_dev == st.st_dev)
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{
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/* It's the same file. No further work needed. */
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fclose (f);
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__use_tzfile = 1;
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return;
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}
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free ((void *) transitions);
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transitions = NULL;
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/* Remember the inode and device number. */
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tzfile_dev = st.st_dev;
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tzfile_ino = st.st_ino;
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/* No threads reading this stream. */
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__fsetlocking (f, FSETLOCKING_BYCALLER);
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if (__builtin_expect (fread_unlocked ((void *) &tzhead, sizeof (tzhead),
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1, f) != 1, 0))
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goto lose;
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num_transitions = (size_t) decode (tzhead.tzh_timecnt);
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num_types = (size_t) decode (tzhead.tzh_typecnt);
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chars = (size_t) decode (tzhead.tzh_charcnt);
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num_leaps = (size_t) decode (tzhead.tzh_leapcnt);
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num_isstd = (size_t) decode (tzhead.tzh_ttisstdcnt);
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num_isgmt = (size_t) decode (tzhead.tzh_ttisgmtcnt);
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total_size = num_transitions * (sizeof (time_t) + 1);
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total_size = ((total_size + __alignof__ (struct ttinfo) - 1)
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& ~(__alignof__ (struct ttinfo) - 1));
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types_idx = total_size;
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total_size += num_types * sizeof (struct ttinfo) + chars;
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total_size = ((total_size + __alignof__ (struct leap) - 1)
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& ~(__alignof__ (struct leap) - 1));
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leaps_idx = total_size;
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total_size += num_leaps * sizeof (struct leap);
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/* This is for the extra memory required by the caller. */
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total_size += extra;
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transitions = (time_t *) malloc (total_size);
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if (transitions == NULL)
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goto lose;
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type_idxs = (unsigned char *) transitions + (num_transitions
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* sizeof (time_t));
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types = (struct ttinfo *) ((char *) transitions + types_idx);
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zone_names = (char *) types + num_types * sizeof (struct ttinfo);
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leaps = (struct leap *) ((char *) transitions + leaps_idx);
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if (extra > 0)
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*extrap = (char *) &leaps[num_leaps];
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if (sizeof (time_t) < 4)
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abort ();
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if (sizeof (time_t) == 4)
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{
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if (__builtin_expect (fread_unlocked (transitions, 1,
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(4 + 1) * num_transitions, f)
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!= (4 + 1) * num_transitions, 0))
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goto lose;
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}
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else
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{
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if (__builtin_expect (fread_unlocked (transitions, 4, num_transitions, f)
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!= num_transitions, 0)
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|| __builtin_expect (fread_unlocked (type_idxs, 1, num_transitions,
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f) != num_transitions, 0))
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goto lose;
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}
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/* Check for bogus indices in the data file, so we can hereafter
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safely use type_idxs[T] as indices into `types' and never crash. */
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for (i = 0; i < num_transitions; ++i)
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if (__builtin_expect (type_idxs[i] >= num_types, 0))
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goto lose;
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if (BYTE_ORDER != BIG_ENDIAN || sizeof (time_t) != 4)
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{
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/* Decode the transition times, stored as 4-byte integers in
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network (big-endian) byte order. We work from the end of
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the array so as not to clobber the next element to be
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processed when sizeof (time_t) > 4. */
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i = num_transitions;
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while (i-- > 0)
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transitions[i] = decode ((char *) transitions + i * 4);
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}
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for (i = 0; i < num_types; ++i)
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{
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unsigned char x[4];
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int c;
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if (__builtin_expect (fread_unlocked (x, 1, sizeof (x), f) != sizeof (x),
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0))
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goto lose;
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c = getc_unlocked (f);
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if (__builtin_expect ((unsigned int) c > 1u, 0))
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goto lose;
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types[i].isdst = c;
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c = getc_unlocked (f);
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if (__builtin_expect ((size_t) c > chars, 0))
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/* Bogus index in data file. */
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goto lose;
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types[i].idx = c;
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types[i].offset = (long int) decode (x);
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}
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if (__builtin_expect (fread_unlocked (zone_names, 1, chars, f) != chars, 0))
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goto lose;
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for (i = 0; i < num_leaps; ++i)
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{
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unsigned char x[4];
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if (__builtin_expect (fread_unlocked (x, 1, sizeof (x), f) != sizeof (x),
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0))
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goto lose;
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leaps[i].transition = (time_t) decode (x);
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if (__builtin_expect (fread_unlocked (x, 1, sizeof (x), f) != sizeof (x),
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0))
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goto lose;
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leaps[i].change = (long int) decode (x);
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}
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for (i = 0; i < num_isstd; ++i)
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{
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int c = getc_unlocked (f);
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if (__builtin_expect (c == EOF, 0))
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goto lose;
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types[i].isstd = c != 0;
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}
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while (i < num_types)
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types[i++].isstd = 0;
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for (i = 0; i < num_isgmt; ++i)
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{
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int c = getc_unlocked (f);
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if (__builtin_expect (c == EOF, 0))
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goto lose;
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types[i].isgmt = c != 0;
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}
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while (i < num_types)
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types[i++].isgmt = 0;
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fclose (f);
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/* First "register" all timezone names. */
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for (i = 0; i < num_types; ++i)
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(void) __tzstring (&zone_names[types[i].idx]);
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/* Find the standard and daylight time offsets used by the rule file.
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We choose the offsets in the types of each flavor that are
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transitioned to earliest in time. */
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__tzname[0] = NULL;
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__tzname[1] = NULL;
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for (i = num_transitions; i > 0; )
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{
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int type = type_idxs[--i];
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int dst = types[type].isdst;
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if (__tzname[dst] == NULL)
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{
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int idx = types[type].idx;
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__tzname[dst] = __tzstring (&zone_names[idx]);
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if (__tzname[1 - dst] != NULL)
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break;
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}
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}
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if (__tzname[0] == NULL)
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{
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/* This should only happen if there are no transition rules.
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In this case there should be only one single type. */
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assert (num_types == 1);
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__tzname[0] = __tzstring (zone_names);
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}
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if (__tzname[1] == NULL)
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__tzname[1] = __tzname[0];
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compute_tzname_max (chars);
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if (num_transitions == 0)
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/* Use the first rule (which should also be the only one). */
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rule_stdoff = rule_dstoff = types[0].offset;
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else
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{
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int stdoff_set = 0, dstoff_set = 0;
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rule_stdoff = rule_dstoff = 0;
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i = num_transitions - 1;
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do
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{
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if (!stdoff_set && !types[type_idxs[i]].isdst)
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{
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stdoff_set = 1;
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rule_stdoff = types[type_idxs[i]].offset;
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}
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else if (!dstoff_set && types[type_idxs[i]].isdst)
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{
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dstoff_set = 1;
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rule_dstoff = types[type_idxs[i]].offset;
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}
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if (stdoff_set && dstoff_set)
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break;
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}
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while (i-- > 0);
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if (!dstoff_set)
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rule_dstoff = rule_stdoff;
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}
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__daylight = rule_stdoff != rule_dstoff;
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__timezone = -rule_stdoff;
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__use_tzfile = 1;
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return;
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lose:
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fclose (f);
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ret_free_transitions:
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free ((void *) transitions);
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transitions = NULL;
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}
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/* The user specified a hand-made timezone, but not its DST rules.
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We will use the names and offsets from the user, and the rules
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from the TZDEFRULES file. */
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void
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__tzfile_default (const char *std, const char *dst,
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long int stdoff, long int dstoff)
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{
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size_t stdlen = strlen (std) + 1;
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size_t dstlen = strlen (dst) + 1;
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size_t i;
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int isdst;
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char *cp;
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__tzfile_read (TZDEFRULES, stdlen + dstlen, &cp);
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if (!__use_tzfile)
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return;
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if (num_types < 2)
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{
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__use_tzfile = 0;
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return;
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}
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/* Ignore the zone names read from the file and use the given ones
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instead. */
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__mempcpy (__mempcpy (cp, std, stdlen), dst, dstlen);
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zone_names = cp;
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/* Now there are only two zones, regardless of what the file contained. */
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num_types = 2;
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/* Now correct the transition times for the user-specified standard and
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daylight offsets from GMT. */
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isdst = 0;
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for (i = 0; i < num_transitions; ++i)
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{
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struct ttinfo *trans_type = &types[type_idxs[i]];
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/* We will use only types 0 (standard) and 1 (daylight).
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Fix up this transition to point to whichever matches
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the flavor of its original type. */
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type_idxs[i] = trans_type->isdst;
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if (trans_type->isgmt)
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/* The transition time is in GMT. No correction to apply. */ ;
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else if (isdst && !trans_type->isstd)
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/* The type says this transition is in "local wall clock time", and
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wall clock time as of the previous transition was DST. Correct
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for the difference between the rule's DST offset and the user's
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DST offset. */
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transitions[i] += dstoff - rule_dstoff;
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else
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/* This transition is in "local wall clock time", and wall clock
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time as of this iteration is non-DST. Correct for the
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difference between the rule's standard offset and the user's
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standard offset. */
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transitions[i] += stdoff - rule_stdoff;
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/* The DST state of "local wall clock time" for the next iteration is
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as specified by this transition. */
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isdst = trans_type->isdst;
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}
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/* Now that we adjusted the transitions to the requested offsets,
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reset the rule_stdoff and rule_dstoff values appropriately. They
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are used elsewhere. */
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rule_stdoff = stdoff;
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rule_dstoff = dstoff;
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/* Reset types 0 and 1 to describe the user's settings. */
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types[0].idx = 0;
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types[0].offset = stdoff;
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types[0].isdst = 0;
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types[1].idx = stdlen;
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types[1].offset = dstoff;
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types[1].isdst = 1;
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/* Reset the zone names to point to the user's names. */
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__tzname[0] = (char *) std;
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__tzname[1] = (char *) dst;
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/* Set the timezone. */
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__timezone = -types[0].offset;
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compute_tzname_max (stdlen + dstlen);
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}
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static struct ttinfo *
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internal_function
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find_transition (time_t timer)
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{
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size_t i;
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if (num_transitions == 0 || timer < transitions[0])
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{
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/* TIMER is before any transition (or there are no transitions).
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Choose the first non-DST type
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(or the first if they're all DST types). */
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i = 0;
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while (i < num_types && types[i].isdst)
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++i;
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if (i == num_types)
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i = 0;
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}
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else
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{
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/* Find the first transition after TIMER, and
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then pick the type of the transition before it. */
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for (i = 1; i < num_transitions; ++i)
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if (timer < transitions[i])
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break;
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i = type_idxs[i - 1];
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}
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return &types[i];
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}
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void
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__tzfile_compute (time_t timer, int use_localtime,
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||
long int *leap_correct, int *leap_hit,
|
||
struct tm *tp)
|
||
{
|
||
register size_t i;
|
||
|
||
if (use_localtime)
|
||
{
|
||
struct ttinfo *info = find_transition (timer);
|
||
__daylight = rule_stdoff != rule_dstoff;
|
||
__timezone = -rule_stdoff;
|
||
__tzname[0] = NULL;
|
||
__tzname[1] = NULL;
|
||
for (i = num_transitions; i > 0; )
|
||
{
|
||
int type = type_idxs[--i];
|
||
int dst = types[type].isdst;
|
||
int idx = types[type].idx;
|
||
|
||
if (__tzname[dst] == NULL)
|
||
{
|
||
__tzname[dst] = __tzstring (&zone_names[idx]);
|
||
|
||
if (__tzname[1 - dst] != NULL)
|
||
break;
|
||
}
|
||
}
|
||
if (__tzname[0] == NULL)
|
||
{
|
||
/* This should only happen if there are no transition rules.
|
||
In this case there should be only one single type. */
|
||
assert (num_types == 1);
|
||
__tzname[0] = __tzstring (zone_names);
|
||
}
|
||
if (__tzname[1] == NULL)
|
||
/* There is no daylight saving time. */
|
||
__tzname[1] = __tzname[0];
|
||
tp->tm_isdst = info->isdst;
|
||
tp->tm_zone = __tzstring (&zone_names[info->idx]);
|
||
tp->tm_gmtoff = info->offset;
|
||
}
|
||
|
||
*leap_correct = 0L;
|
||
*leap_hit = 0;
|
||
|
||
/* Find the last leap second correction transition time before TIMER. */
|
||
i = num_leaps;
|
||
do
|
||
if (i-- == 0)
|
||
return;
|
||
while (timer < leaps[i].transition);
|
||
|
||
/* Apply its correction. */
|
||
*leap_correct = leaps[i].change;
|
||
|
||
if (timer == leaps[i].transition && /* Exactly at the transition time. */
|
||
((i == 0 && leaps[i].change > 0) ||
|
||
leaps[i].change > leaps[i - 1].change))
|
||
{
|
||
*leap_hit = 1;
|
||
while (i > 0
|
||
&& leaps[i].transition == leaps[i - 1].transition + 1
|
||
&& leaps[i].change == leaps[i - 1].change + 1)
|
||
{
|
||
++*leap_hit;
|
||
--i;
|
||
}
|
||
}
|
||
}
|
||
|
||
static void
|
||
internal_function
|
||
compute_tzname_max (size_t chars)
|
||
{
|
||
const char *p;
|
||
|
||
p = zone_names;
|
||
do
|
||
{
|
||
const char *start = p;
|
||
while (*p != '\0')
|
||
++p;
|
||
if ((size_t) (p - start) > __tzname_cur_max)
|
||
__tzname_cur_max = p - start;
|
||
}
|
||
while (++p < &zone_names[chars]);
|
||
}
|