Adding upstream version 9.1.upstream/9.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 317 insertions, 0 deletions

diff --git a/lib/time_rz.c b/lib/time_rz.c
new file mode 100644
index 0000000..1a91d37
--- /dev/null
+++ b/lib/time_rz.c
@@ -0,0 +1,317 @@
+/* Time zone functions such as tzalloc and localtime_rz
+
+   Copyright 2015-2022 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation, either version 3 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert.  */
+
+/* Although this module is not thread-safe, any races should be fairly
+   rare and reasonably benign.  For complete thread-safety, use a C
+   library with a working timezone_t type, so that this module is not
+   needed.  */
+
+#include <config.h>
+
+#include <time.h>
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "flexmember.h"
+#include "idx.h"
+#include "time-internal.h"
+
+/* The approximate size to use for small allocation requests.  This is
+   the largest "small" request for the GNU C library malloc.  */
+enum { DEFAULT_MXFAST = 64 * sizeof (size_t) / 4 };
+
+/* Minimum size of the ABBRS member of struct tm_zone.  ABBRS is larger
+   only in the unlikely case where an abbreviation longer than this is
+   used.  */
+enum { ABBR_SIZE_MIN = DEFAULT_MXFAST - offsetof (struct tm_zone, abbrs) };
+
+/* Magic cookie timezone_t value, for local time.  It differs from
+   NULL and from all other timezone_t values.  Only the address
+   matters; the pointer is never dereferenced.  */
+static timezone_t const local_tz = (timezone_t) 1;
+
+/* Copy to ABBRS the abbreviation at ABBR with size ABBR_SIZE (this
+   includes its trailing null byte).  Append an extra null byte to
+   mark the end of ABBRS.  */
+static void
+extend_abbrs (char *abbrs, char const *abbr, size_t abbr_size)
+{
+  memcpy (abbrs, abbr, abbr_size);
+  abbrs[abbr_size] = '\0';
+}
+
+/* Return a newly allocated time zone for NAME, or NULL on failure.
+   A null NAME stands for wall clock time (which is like unset TZ).  */
+timezone_t
+tzalloc (char const *name)
+{
+  size_t name_size = name ? strlen (name) + 1 : 0;
+  size_t abbr_size = name_size < ABBR_SIZE_MIN ? ABBR_SIZE_MIN : name_size + 1;
+  timezone_t tz = malloc (FLEXSIZEOF (struct tm_zone, abbrs, abbr_size));
+  if (tz)
+    {
+      tz->next = NULL;
+#if HAVE_TZNAME && !HAVE_STRUCT_TM_TM_ZONE
+      tz->tzname_copy[0] = tz->tzname_copy[1] = NULL;
+#endif
+      tz->tz_is_set = !!name;
+      tz->abbrs[0] = '\0';
+      if (name)
+        extend_abbrs (tz->abbrs, name, name_size);
+    }
+  return tz;
+}
+
+/* Save into TZ any nontrivial time zone abbreviation used by TM, and
+   update *TM (if HAVE_STRUCT_TM_TM_ZONE) or *TZ (if
+   !HAVE_STRUCT_TM_TM_ZONE && HAVE_TZNAME) if they use the abbreviation.
+   Return true if successful, false (setting errno) otherwise.  */
+static bool
+save_abbr (timezone_t tz, struct tm *tm)
+{
+#if HAVE_STRUCT_TM_TM_ZONE || HAVE_TZNAME
+  char const *zone = NULL;
+  char *zone_copy = (char *) "";
+
+# if HAVE_TZNAME
+  int tzname_index = -1;
+# endif
+
+# if HAVE_STRUCT_TM_TM_ZONE
+  zone = tm->tm_zone;
+# endif
+
+# if HAVE_TZNAME
+  if (! (zone && *zone) && 0 <= tm->tm_isdst)
+    {
+      tzname_index = tm->tm_isdst != 0;
+      zone = tzname[tzname_index];
+    }
+# endif
+
+  /* No need to replace null zones, or zones within the struct tm.  */
+  if (!zone || ((char *) tm <= zone && zone < (char *) (tm + 1)))
+    return true;
+
+  if (*zone)
+    {
+      zone_copy = tz->abbrs;
+
+      while (strcmp (zone_copy, zone) != 0)
+        {
+          if (! (*zone_copy || (zone_copy == tz->abbrs && tz->tz_is_set)))
+            {
+              idx_t zone_size = strlen (zone) + 1;
+              if (zone_size < tz->abbrs + ABBR_SIZE_MIN - zone_copy)
+                extend_abbrs (zone_copy, zone, zone_size);
+              else
+                {
+                  tz = tz->next = tzalloc (zone);
+                  if (!tz)
+                    return false;
+                  tz->tz_is_set = 0;
+                  zone_copy = tz->abbrs;
+                }
+              break;
+            }
+
+          zone_copy += strlen (zone_copy) + 1;
+          if (!*zone_copy && tz->next)
+            {
+              tz = tz->next;
+              zone_copy = tz->abbrs;
+            }
+        }
+    }
+
+  /* Replace the zone name so that its lifetime matches that of TZ.  */
+# if HAVE_STRUCT_TM_TM_ZONE
+  tm->tm_zone = zone_copy;
+# else
+  if (0 <= tzname_index)
+    tz->tzname_copy[tzname_index] = zone_copy;
+# endif
+#endif
+
+  return true;
+}
+
+/* Free a time zone.  */
+void
+tzfree (timezone_t tz)
+{
+  if (tz != local_tz)
+    while (tz)
+      {
+        timezone_t next = tz->next;
+        free (tz);
+        tz = next;
+      }
+}
+
+/* Get and set the TZ environment variable.  These functions can be
+   overridden by programs like Emacs that manage their own environment.  */
+
+#ifndef getenv_TZ
+static char *
+getenv_TZ (void)
+{
+  return getenv ("TZ");
+}
+#endif
+
+#ifndef setenv_TZ
+static int
+setenv_TZ (char const *tz)
+{
+  return tz ? setenv ("TZ", tz, 1) : unsetenv ("TZ");
+}
+#endif
+
+/* Change the environment to match the specified timezone_t value.
+   Return true if successful, false (setting errno) otherwise.  */
+static bool
+change_env (timezone_t tz)
+{
+  if (setenv_TZ (tz->tz_is_set ? tz->abbrs : NULL) != 0)
+    return false;
+  tzset ();
+  return true;
+}
+
+/* Temporarily set the time zone to TZ, which must not be null.
+   Return LOCAL_TZ if the time zone setting is already correct.
+   Otherwise return a newly allocated time zone representing the old
+   setting, or NULL (setting errno) on failure.  */
+static timezone_t
+set_tz (timezone_t tz)
+{
+  char *env_tz = getenv_TZ ();
+  if (env_tz
+      ? tz->tz_is_set && strcmp (tz->abbrs, env_tz) == 0
+      : !tz->tz_is_set)
+    return local_tz;
+  else
+    {
+      timezone_t old_tz = tzalloc (env_tz);
+      if (!old_tz)
+        return old_tz;
+      if (! change_env (tz))
+        {
+          int saved_errno = errno;
+          tzfree (old_tz);
+          errno = saved_errno;
+          return NULL;
+        }
+      return old_tz;
+    }
+}
+
+/* Restore an old setting returned by set_tz.  It must not be null.
+   Return true (preserving errno) if successful, false (setting errno)
+   otherwise.  */
+static bool
+revert_tz (timezone_t tz)
+{
+  if (tz == local_tz)
+    return true;
+  else
+    {
+      int saved_errno = errno;
+      bool ok = change_env (tz);
+      if (!ok)
+        saved_errno = errno;
+      tzfree (tz);
+      errno = saved_errno;
+      return ok;
+    }
+}
+
+/* Use time zone TZ to compute localtime_r (T, TM).  */
+struct tm *
+localtime_rz (timezone_t tz, time_t const *t, struct tm *tm)
+{
+#ifdef HAVE_LOCALTIME_INFLOOP_BUG
+  /* The -67768038400665599 comes from:
+     https://lists.gnu.org/r/bug-gnulib/2017-07/msg00142.html
+     On affected platforms the greatest POSIX-compatible time_t value
+     that could return nonnull is 67768036191766798 (when
+     TZ="XXX24:59:59" it resolves to the year 2**31 - 1 + 1900, on
+     12-31 at 23:59:59), so test for that too while we're in the
+     neighborhood.  */
+  if (! (-67768038400665599 <= *t && *t <= 67768036191766798))
+    {
+      errno = EOVERFLOW;
+      return NULL;
+    }
+#endif
+
+  if (!tz)
+    return gmtime_r (t, tm);
+  else
+    {
+      timezone_t old_tz = set_tz (tz);
+      if (old_tz)
+        {
+          bool abbr_saved = localtime_r (t, tm) && save_abbr (tz, tm);
+          if (revert_tz (old_tz) && abbr_saved)
+            return tm;
+        }
+      return NULL;
+    }
+}
+
+/* Use time zone TZ to compute mktime (TM).  */
+time_t
+mktime_z (timezone_t tz, struct tm *tm)
+{
+  if (!tz)
+    return timegm (tm);
+  else
+    {
+      timezone_t old_tz = set_tz (tz);
+      if (old_tz)
+        {
+          struct tm tm_1;
+          tm_1.tm_sec = tm->tm_sec;
+          tm_1.tm_min = tm->tm_min;
+          tm_1.tm_hour = tm->tm_hour;
+          tm_1.tm_mday = tm->tm_mday;
+          tm_1.tm_mon = tm->tm_mon;
+          tm_1.tm_year = tm->tm_year;
+          tm_1.tm_yday = -1;
+          tm_1.tm_isdst = tm->tm_isdst;
+          time_t t = mktime (&tm_1);
+          bool ok = 0 <= tm_1.tm_yday;
+#if HAVE_STRUCT_TM_TM_ZONE || HAVE_TZNAME
+          ok = ok && save_abbr (tz, &tm_1);
+#endif
+          if (revert_tz (old_tz) && ok)
+            {
+              *tm = tm_1;
+              return t;
+            }
+        }
+      return -1;
+    }
+}