Adding upstream version 2.2.40.upstream/2.2.40upstream

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

1 files changed, 1064 insertions, 0 deletions

diff --git a/common/gettime.c b/common/gettime.c
new file mode 100644
index 0000000..3fe30ce
--- /dev/null
+++ b/common/gettime.c
@@ -0,0 +1,1064 @@
+/* gettime.c - Wrapper for time functions
+ * Copyright (C) 1998, 2002, 2007, 2011 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - 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.
+ *
+ * or
+ *
+ *   - the GNU General Public License as published by the Free
+ *     Software Foundation; either version 2 of the License, or (at
+ *     your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <time.h>
+#include <ctype.h>
+#ifdef HAVE_LOCALE_H
+#include <locale.h>
+#endif
+#ifdef HAVE_LANGINFO_H
+#include <langinfo.h>
+#endif
+
+#include "util.h"
+#include "i18n.h"
+#include "gettime.h"
+
+#ifdef HAVE_UNSIGNED_TIME_T
+# define IS_INVALID_TIME_T(a) ((a) == (time_t)(-1))
+#else
+  /* Error or 32 bit time_t and value after 2038-01-19.  */
+# define IS_INVALID_TIME_T(a) ((a) < 0)
+#endif
+
+
+static unsigned long timewarp;
+static enum { NORMAL = 0, FROZEN, FUTURE, PAST } timemode;
+
+/* Correction used to map to real Julian days. */
+#define JD_DIFF 1721060L
+
+
+/* Wrapper for the time(3).  We use this here so we can fake the time
+   for tests */
+time_t
+gnupg_get_time ()
+{
+  time_t current = time (NULL);
+  if (current == (time_t)(-1))
+    log_fatal ("time() failed\n");
+
+  if (timemode == NORMAL)
+    return current;
+  else if (timemode == FROZEN)
+    return timewarp;
+  else if (timemode == FUTURE)
+    return current + timewarp;
+  else
+    return current - timewarp;
+}
+
+
+/* Wrapper around gmtime_r.
+
+   On systems without gmtime_r this implementation works within gnupg
+   because we use only one thread a time.  FIXME: An independent
+   library may use gmtime in one of its own thread (or via
+   npth_enter/npth_leave) - in this case we run into a problem.  The
+   solution would be to use a mutex here.  */
+struct tm *
+gnupg_gmtime (const time_t *timep, struct tm *result)
+{
+#ifdef HAVE_GMTIME_R
+  return gmtime_r (timep, result);
+#else
+  struct tm *tp;
+
+  tp = gmtime (timep);
+  if (tp)
+    memcpy (result, tp, sizeof *result);
+  return tp;
+#endif
+}
+
+
+/* Return the current time (possibly faked) in ISO format. */
+void
+gnupg_get_isotime (gnupg_isotime_t timebuf)
+{
+  time_t atime = gnupg_get_time ();
+  struct tm *tp;
+  struct tm tmbuf;
+
+  tp = gnupg_gmtime (&atime, &tmbuf);
+  if (!tp)
+    *timebuf = 0;
+  else
+    snprintf (timebuf, 16, "%04d%02d%02dT%02d%02d%02d",
+              1900 + tp->tm_year, tp->tm_mon+1, tp->tm_mday,
+              tp->tm_hour, tp->tm_min, tp->tm_sec);
+}
+
+
+/* Set the time to NEWTIME so that gnupg_get_time returns a time
+   starting with this one.  With FREEZE set to 1 the returned time
+   will never change.  Just for completeness, a value of (time_t)-1
+   for NEWTIME gets you back to reality.  Note that this is obviously
+   not thread-safe but this is not required. */
+void
+gnupg_set_time (time_t newtime, int freeze)
+{
+  time_t current = time (NULL);
+
+  if ( newtime == (time_t)-1 || current == newtime)
+    {
+      timemode = NORMAL;
+      timewarp = 0;
+    }
+  else if (freeze)
+    {
+      timemode = FROZEN;
+      timewarp = newtime == (time_t)-1 ? current : newtime;
+    }
+  else if (newtime > current)
+    {
+      timemode = FUTURE;
+      timewarp = newtime - current;
+    }
+  else
+    {
+      timemode = PAST;
+      timewarp = current - newtime;
+    }
+}
+
+/* Returns true when we are in timewarp mode */
+int
+gnupg_faked_time_p (void)
+{
+  return timemode;
+}
+
+
+/* This function is used by gpg because OpenPGP defines the timestamp
+   as an unsigned 32 bit value. */
+u32
+make_timestamp (void)
+{
+  time_t t = gnupg_get_time ();
+  return (u32)t;
+}
+
+
+
+/****************
+ * Scan a date string and return a timestamp.
+ * The only supported format is "yyyy-mm-dd"
+ * Returns 0 for an invalid date.
+ */
+u32
+scan_isodatestr( const char *string )
+{
+    int year, month, day;
+    struct tm tmbuf;
+    time_t stamp;
+    int i;
+
+    if( strlen(string) != 10 || string[4] != '-' || string[7] != '-' )
+	return 0;
+    for( i=0; i < 4; i++ )
+	if( !digitp (string+i) )
+	    return 0;
+    if( !digitp (string+5) || !digitp(string+6) )
+	return 0;
+    if( !digitp(string+8) || !digitp(string+9) )
+	return 0;
+    year = atoi(string);
+    month = atoi(string+5);
+    day = atoi(string+8);
+    /* some basic checks */
+    if( year < 1970 || month < 1 || month > 12 || day < 1 || day > 31 )
+	return 0;
+    memset( &tmbuf, 0, sizeof tmbuf );
+    tmbuf.tm_mday = day;
+    tmbuf.tm_mon = month-1;
+    tmbuf.tm_year = year - 1900;
+    tmbuf.tm_isdst = -1;
+    stamp = mktime( &tmbuf );
+    if( stamp == (time_t)-1 )
+	return 0;
+    return stamp;
+}
+
+
+int
+isotime_p (const char *string)
+{
+  const char *s;
+  int i;
+
+  if (!*string)
+    return 0;
+  for (s=string, i=0; i < 8; i++, s++)
+    if (!digitp (s))
+      return 0;
+  if (*s != 'T')
+      return 0;
+  for (s++, i=9; i < 15; i++, s++)
+    if (!digitp (s))
+      return 0;
+  if (*s == 'Z')
+    s++;
+  if ( !(!*s || (isascii (*s) && isspace(*s)) || *s == ':' || *s == ','))
+    return 0;  /* Wrong delimiter.  */
+
+  return 1;
+}
+
+
+/* Scan a string and return true if the string represents the human
+   readable format of an ISO time.  This format is:
+      yyyy-mm-dd[ hh[:mm[:ss]]]
+   Scanning stops at the second space or at a comma.  If DATE_ONLY is
+   true the time part is not expected and the scanning stops at the
+   first space or at a comma. */
+int
+isotime_human_p (const char *string, int date_only)
+{
+  const char *s;
+  int i;
+
+  if (!*string)
+    return 0;
+  for (s=string, i=0; i < 4; i++, s++)
+    if (!digitp (s))
+      return 0;
+  if (*s != '-')
+    return 0;
+  s++;
+  if (!digitp (s) || !digitp (s+1) || s[2] != '-')
+    return 0;
+  i = atoi_2 (s);
+  if (i < 1 || i > 12)
+    return 0;
+  s += 3;
+  if (!digitp (s) || !digitp (s+1))
+    return 0;
+  i = atoi_2 (s);
+  if (i < 1 || i > 31)
+    return 0;
+  s += 2;
+  if (!*s || *s == ',')
+    return 1; /* Okay; only date given.  */
+  if (!spacep (s))
+    return 0;
+  if (date_only)
+    return 1; /* Okay; only date was requested.  */
+  s++;
+  if (spacep (s))
+    return 1; /* Okay, second space stops scanning.  */
+  if (!digitp (s) || !digitp (s+1))
+    return 0;
+  i = atoi_2 (s);
+  if (i < 0 || i > 23)
+    return 0;
+  s += 2;
+  if (!*s || *s == ',')
+    return 1; /* Okay; only date and hour given.  */
+  if (*s != ':')
+    return 0;
+  s++;
+  if (!digitp (s) || !digitp (s+1))
+    return 0;
+  i = atoi_2 (s);
+  if (i < 0 || i > 59)
+    return 0;
+  s += 2;
+  if (!*s || *s == ',')
+    return 1; /* Okay; only date, hour and minute given.  */
+  if (*s != ':')
+    return 0;
+  s++;
+  if (!digitp (s) || !digitp (s+1))
+    return 0;
+  i = atoi_2 (s);
+  if (i < 0 || i > 60)
+    return 0;
+  s += 2;
+  if (!*s || *s == ',' || spacep (s))
+    return 1; /* Okay; date, hour and minute and second given.  */
+
+  return 0; /* Unexpected delimiter.  */
+}
+
+/* Convert a standard isotime or a human readable variant into an
+   isotime structure.  The allowed formats are those described by
+   isotime_p and isotime_human_p.  The function returns 0 on failure
+   or the length of the scanned string on success.  */
+size_t
+string2isotime (gnupg_isotime_t atime, const char *string)
+{
+  gnupg_isotime_t dummyatime;
+
+  if (!atime)
+    atime = dummyatime;
+
+  atime[0] = 0;
+  if (isotime_p (string))
+    {
+      memcpy (atime, string, 15);
+      atime[15] = 0;
+      return 15;
+    }
+  if (!isotime_human_p (string, 0))
+    return 0;
+  atime[0] = string[0];
+  atime[1] = string[1];
+  atime[2] = string[2];
+  atime[3] = string[3];
+  atime[4] = string[5];
+  atime[5] = string[6];
+  atime[6] = string[8];
+  atime[7] = string[9];
+  atime[8] = 'T';
+  memset (atime+9, '0', 6);
+  atime[15] = 0;
+  if (!spacep (string+10))
+    return 10;
+  if (spacep (string+11))
+    return 11; /* As per def, second space stops scanning.  */
+  atime[9] = string[11];
+  atime[10] = string[12];
+  if (string[13] != ':')
+    return 13;
+  atime[11] = string[14];
+  atime[12] = string[15];
+  if (string[16] != ':')
+    return 16;
+  atime[13] = string[17];
+  atime[14] = string[18];
+  return 19;
+}
+
+
+/* Scan an ISO timestamp and return an Epoch based timestamp.  The
+   only supported format is "yyyymmddThhmmss[Z]" delimited by white
+   space, nul, a colon or a comma.  Returns (time_t)(-1) for an
+   invalid string.  */
+time_t
+isotime2epoch (const char *string)
+{
+  int year, month, day, hour, minu, sec;
+  struct tm tmbuf;
+
+  if (!isotime_p (string))
+    return (time_t)(-1);
+
+  year  = atoi_4 (string);
+  month = atoi_2 (string + 4);
+  day   = atoi_2 (string + 6);
+  hour  = atoi_2 (string + 9);
+  minu  = atoi_2 (string + 11);
+  sec   = atoi_2 (string + 13);
+
+  /* Basic checks.  */
+  if (year < 1970 || month < 1 || month > 12 || day < 1 || day > 31
+      || hour > 23 || minu > 59 || sec > 61 )
+    return (time_t)(-1);
+
+  memset (&tmbuf, 0, sizeof tmbuf);
+  tmbuf.tm_sec  = sec;
+  tmbuf.tm_min  = minu;
+  tmbuf.tm_hour = hour;
+  tmbuf.tm_mday = day;
+  tmbuf.tm_mon  = month-1;
+  tmbuf.tm_year = year - 1900;
+  tmbuf.tm_isdst = -1;
+  return timegm (&tmbuf);
+}
+
+
+/* Convert an Epoch time to an iso time stamp. */
+void
+epoch2isotime (gnupg_isotime_t timebuf, time_t atime)
+{
+  if (atime == (time_t)(-1))
+    *timebuf = 0;
+  else
+    {
+      struct tm *tp;
+#ifdef HAVE_GMTIME_R
+      struct tm tmbuf;
+
+      tp = gmtime_r (&atime, &tmbuf);
+#else
+      tp = gmtime (&atime);
+#endif
+      snprintf (timebuf, 16, "%04d%02d%02dT%02d%02d%02d",
+                1900 + tp->tm_year, tp->tm_mon+1, tp->tm_mday,
+                tp->tm_hour, tp->tm_min, tp->tm_sec);
+    }
+}
+
+
+/* Parse a short ISO date string (YYYY-MM-DD) into a TM structure.
+   Returns 0 on success.  */
+int
+isodate_human_to_tm (const char *string, struct tm *t)
+{
+  int year, month, day;
+
+  if (!isotime_human_p (string, 1))
+    return -1;
+
+  year  = atoi_4 (string);
+  month = atoi_2 (string + 5);
+  day   = atoi_2 (string + 8);
+
+  /* Basic checks.  */
+  if (year < 1970 || month < 1 || month > 12 || day < 1 || day > 31)
+    return -1;
+
+  memset (t, 0, sizeof *t);
+  t->tm_sec  = 0;
+  t->tm_min  = 0;
+  t->tm_hour = 0;
+  t->tm_mday = day;
+  t->tm_mon  = month-1;
+  t->tm_year = year - 1900;
+  t->tm_isdst = -1;
+  return 0;
+}
+
+
+/* This function is a copy of gpgme/src/conversion.c:_gpgme_timegm.
+   If you change it, then update the other one too.  */
+#ifdef HAVE_W32_SYSTEM
+static time_t
+_win32_timegm (struct tm *tm)
+{
+  /* This one is thread safe.  */
+  SYSTEMTIME st;
+  FILETIME ft;
+  unsigned long long cnsecs;
+
+  st.wYear   = tm->tm_year + 1900;
+  st.wMonth  = tm->tm_mon  + 1;
+  st.wDay    = tm->tm_mday;
+  st.wHour   = tm->tm_hour;
+  st.wMinute = tm->tm_min;
+  st.wSecond = tm->tm_sec;
+  st.wMilliseconds = 0; /* Not available.  */
+  st.wDayOfWeek = 0;    /* Ignored.  */
+
+  /* System time is UTC thus the conversion is pretty easy.  */
+  if (!SystemTimeToFileTime (&st, &ft))
+    {
+      gpg_err_set_errno (EINVAL);
+      return (time_t)(-1);
+    }
+
+  cnsecs = (((unsigned long long)ft.dwHighDateTime << 32)
+	    | ft.dwLowDateTime);
+  cnsecs -= 116444736000000000ULL; /* The filetime epoch is 1601-01-01.  */
+  return (time_t)(cnsecs / 10000000ULL);
+}
+#endif
+
+
+/* Parse the string TIMESTAMP into a time_t.  The string may either be
+   seconds since Epoch or in the ISO 8601 format like
+   "20390815T143012".  Returns 0 for an empty string or seconds since
+   Epoch. Leading spaces are skipped. If ENDP is not NULL, it will
+   point to the next non-parsed character in TIMESTRING.
+
+   This function is a copy of
+   gpgme/src/conversion.c:_gpgme_parse_timestamp.  If you change it,
+   then update the other one too.  */
+time_t
+parse_timestamp (const char *timestamp, char **endp)
+{
+  /* Need to skip leading spaces, because that is what strtoul does
+     but not our ISO 8601 checking code. */
+  while (*timestamp && *timestamp== ' ')
+    timestamp++;
+  if (!*timestamp)
+    return 0;
+
+  if (strlen (timestamp) >= 15 && timestamp[8] == 'T')
+    {
+      struct tm buf;
+      int year;
+
+      year = atoi_4 (timestamp);
+      if (year < 1900)
+        return (time_t)(-1);
+
+      if (endp)
+        *endp = (char*)(timestamp + 15);
+
+      /* Fixme: We would better use a configure test to see whether
+         mktime can handle dates beyond 2038. */
+      if (sizeof (time_t) <= 4 && year >= 2038)
+        return (time_t)2145914603; /* 2037-12-31 23:23:23 */
+
+      memset (&buf, 0, sizeof buf);
+      buf.tm_year = year - 1900;
+      buf.tm_mon = atoi_2 (timestamp+4) - 1;
+      buf.tm_mday = atoi_2 (timestamp+6);
+      buf.tm_hour = atoi_2 (timestamp+9);
+      buf.tm_min = atoi_2 (timestamp+11);
+      buf.tm_sec = atoi_2 (timestamp+13);
+
+#ifdef HAVE_W32_SYSTEM
+      return _win32_timegm (&buf);
+#else
+#ifdef HAVE_TIMEGM
+      return timegm (&buf);
+#else
+      {
+        time_t tim;
+
+        putenv ("TZ=UTC");
+        tim = mktime (&buf);
+#ifdef __GNUC__
+#warning fixme: we must somehow reset TZ here.  It is not threadsafe anyway.
+#endif
+        return tim;
+      }
+#endif /* !HAVE_TIMEGM */
+#endif /* !HAVE_W32_SYSTEM */
+    }
+  else
+    return (time_t)strtoul (timestamp, endp, 10);
+}
+
+
+
+u32
+add_days_to_timestamp( u32 stamp, u16 days )
+{
+    return stamp + days*86400L;
+}
+
+
+/****************
+ * Return a string with a time value in the form: x Y, n D, n H
+ */
+
+const char *
+strtimevalue( u32 value )
+{
+    static char buffer[30];
+    unsigned int years, days, hours, minutes;
+
+    value /= 60;
+    minutes = value % 60;
+    value /= 60;
+    hours = value % 24;
+    value /= 24;
+    days = value % 365;
+    value /= 365;
+    years = value;
+
+    sprintf(buffer,"%uy%ud%uh%um", years, days, hours, minutes );
+    if( years )
+	return buffer;
+    if( days )
+	return strchr( buffer, 'y' ) + 1;
+    return strchr( buffer, 'd' ) + 1;
+}
+
+
+
+/* Return a malloced string with the time elapsed between NOW and
+   SINCE.  May return NULL on error. */
+char *
+elapsed_time_string (time_t since, time_t now)
+{
+  char *result;
+  double diff;
+  unsigned long value;
+  unsigned int days, hours, minutes, seconds;
+
+  if (!now)
+    now = gnupg_get_time ();
+
+  diff = difftime (now, since);
+  if (diff < 0)
+    return xtrystrdup ("time-warp");
+
+  seconds = (unsigned long)diff % 60;
+  value = (unsigned long)(diff / 60);
+  minutes = value % 60;
+  value /= 60;
+  hours = value % 24;
+  value /= 24;
+  days = value % 365;
+
+  if (days)
+    result = xtryasprintf ("%ud%uh%um%us", days, hours, minutes, seconds);
+  else if (hours)
+    result = xtryasprintf ("%uh%um%us", hours, minutes, seconds);
+  else if (minutes)
+    result = xtryasprintf ("%um%us", minutes, seconds);
+  else
+    result = xtryasprintf ("%us", seconds);
+
+  return result;
+}
+
+
+/*
+ * Note: this function returns GMT
+ */
+const char *
+strtimestamp (u32 stamp)
+{
+  static char buffer[11+5];
+  struct tm *tp;
+  time_t atime = stamp;
+
+  if (IS_INVALID_TIME_T (atime))
+    {
+      strcpy (buffer, "????" "-??" "-??");
+    }
+  else
+    {
+      tp = gmtime( &atime );
+      snprintf (buffer, sizeof buffer, "%04d-%02d-%02d",
+                1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday );
+    }
+  return buffer;
+}
+
+
+/*
+ * Note: this function returns GMT
+ */
+const char *
+isotimestamp (u32 stamp)
+{
+  static char buffer[25+5];
+  struct tm *tp;
+  time_t atime = stamp;
+
+  if (IS_INVALID_TIME_T (atime))
+    {
+      strcpy (buffer, "????" "-??" "-??" " " "??" ":" "??" ":" "??");
+    }
+  else
+    {
+      tp = gmtime ( &atime );
+      snprintf (buffer, sizeof buffer, "%04d-%02d-%02d %02d:%02d:%02d",
+                1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday,
+                tp->tm_hour, tp->tm_min, tp->tm_sec);
+    }
+  return buffer;
+}
+
+
+/* Windows version of strftime returning the string as utf-8.  */
+#ifdef HAVE_W32_SYSTEM
+
+#define strftime(a,b,c,d)  w32_strftime ((a),(b),(c),(d))
+
+static size_t
+w32_strftime (char *s, size_t max, const char *format, const struct tm *tm)
+{
+  wchar_t *wformatbuf = NULL;
+  const wchar_t *wformat = L"%c %Z";
+  wchar_t wbuf[200];
+  size_t n;
+  char *buf;
+
+  if (strcmp (format, "%c %Z"))
+    {
+      log_debug ("  comverted\n");
+      wformatbuf = utf8_to_wchar (format);
+      if (wformatbuf)
+        wformat = wformatbuf;
+    }
+
+  n = wcsftime (wbuf, sizeof wbuf, wformat, tm);
+  xfree (wformatbuf);
+  if (!n)
+    {
+      /* Most likely the buffer is too short - try ISO format instead.  */
+      n = wcsftime (wbuf, sizeof wbuf, L"%Y-%m-%d %H:%M:%S", tm);
+      if (!n)
+        wcscpy (wbuf, L"[????" "-??" "-??]");
+    }
+  buf = wchar_to_utf8 (wbuf);
+  mem2str (s, buf? buf : "[????" "-??" "-??]", max);
+  xfree (buf);
+  return strlen (s) + 1;
+}
+#endif /*HAVE_W32_SYSTEM*/
+
+
+
+/****************
+ * Note: this function returns local time
+ */
+const char *
+asctimestamp (u32 stamp)
+{
+  static char buffer[80];
+#if defined (HAVE_STRFTIME) && defined (HAVE_NL_LANGINFO)
+  static char fmt[80];
+#endif
+  struct tm *tp;
+  time_t atime = stamp;
+
+  if (IS_INVALID_TIME_T (atime))
+    {
+      strcpy (buffer, "????" "-??" "-??");
+      return buffer;
+    }
+  tp = localtime( &atime );
+#ifdef HAVE_STRFTIME
+# if defined(HAVE_NL_LANGINFO)
+  mem2str( fmt, nl_langinfo(D_T_FMT), DIM(fmt)-3 );
+  if (!strstr( fmt, "%Z" ))
+    strcat( fmt, " %Z");
+  /* NOTE: gcc -Wformat-noliteral will complain here.  I have found no
+     way to suppress this warning.  */
+  strftime (buffer, DIM(buffer)-1, fmt, tp);
+# elif defined(HAVE_W32CE_SYSTEM)
+  /* tzset is not available but %Z nevertheless prints a default
+     nonsense timezone ("WILDABBR").  Thus we don't print the time
+     zone at all.  */
+  strftime (buffer, DIM(buffer)-1, "%c", tp);
+# else
+#  if HAVE_W32_SYSTEM
+  {
+    static int done;
+
+    if (!done)
+      {
+        /* The locale names as used by Windows are in the form
+         * "German_Germany.1252" or "German_Austria.1252" with
+         * alternate names similar to Unix, e.g. "de-DE".  However
+         * that is the theory.  On current Windows and Mingw the
+         * alternate names do not work.  We would need a table to map
+         * them from the short names as provided by gpgrt to the long
+         * names and append some code page.  For now we use "" and
+         * take the locale from the user's system settings.  Thus the
+         * standard Unix envvars don't work for time and may mismatch
+         * with the string translations.  The new UCRT available since
+         * 2018 has a lot of additional support but that will for sure
+         * break other things.  We should move to ISO strings to get
+         * rid of such problems.  */
+        setlocale (LC_TIME, "");
+        done = 1;
+        /* log_debug ("LC_ALL  now '%s'\n", setlocale (LC_ALL, NULL)); */
+        /* log_debug ("LC_TIME now '%s'\n", setlocale (LC_TIME, NULL)); */
+      }
+  }
+#  endif
+   /* FIXME: we should check whether the locale appends a " %Z" These
+    * locales from glibc don't put the " %Z": fi_FI hr_HR ja_JP lt_LT
+    * lv_LV POSIX ru_RU ru_SU sv_FI sv_SE zh_CN.  */
+  strftime (buffer, DIM(buffer)-1, "%c %Z", tp);
+# endif
+  buffer[DIM(buffer)-1] = 0;
+#else
+  mem2str( buffer, asctime(tp), DIM(buffer) );
+#endif
+  return buffer;
+}
+
+
+/* Return the timestamp STAMP in RFC-2822 format.  This is always done
+ * in the C locale.  We return the gmtime to avoid computing the
+ * timezone. The caller must release the returned string.
+ *
+ * Example: "Mon, 27 Jun 2016 1:42:00 +0000".
+ */
+char *
+rfctimestamp (u32 stamp)
+{
+  time_t atime = stamp;
+  struct tm tmbuf, *tp;
+
+
+  if (IS_INVALID_TIME_T (atime))
+    {
+      gpg_err_set_errno (EINVAL);
+      return NULL;
+    }
+
+  tp = gnupg_gmtime (&atime, &tmbuf);
+  if (!tp)
+    return NULL;
+  return xtryasprintf ("%.3s, %02d %.3s %04d %02d:%02d:%02d +0000",
+                       &"SunMonTueWedThuFriSat"[(tp->tm_wday%7)*3],
+                       tp->tm_mday,
+                       &"JanFebMarAprMayJunJulAugSepOctNovDec"
+                       [(tp->tm_mon%12)*3],
+                       tp->tm_year + 1900,
+                       tp->tm_hour,
+                       tp->tm_min,
+                       tp->tm_sec);
+}
+
+
+static int
+days_per_year (int y)
+{
+  int s ;
+
+  s = !(y % 4);
+  if ( !(y % 100))
+    if ((y%400))
+      s = 0;
+  return s ? 366 : 365;
+}
+
+static int
+days_per_month (int y, int m)
+{
+  int s;
+
+  switch(m)
+    {
+    case 1: case 3: case 5: case 7: case 8: case 10: case 12:
+      return 31 ;
+    case 2:
+      s = !(y % 4);
+      if (!(y % 100))
+        if ((y % 400))
+          s = 0;
+      return s? 29 : 28 ;
+    case 4: case 6: case 9: case 11:
+      return 30;
+    }
+  BUG();
+}
+
+
+/* Convert YEAR, MONTH and DAY into the Julian date.  We assume that
+   it is already noon.  We do not support dates before 1582-10-15. */
+static unsigned long
+date2jd (int year, int month, int day)
+{
+  unsigned long jd;
+
+  jd = 365L * year + 31 * (month-1) + day + JD_DIFF;
+  if (month < 3)
+    year-- ;
+  else
+    jd -= (4 * month + 23) / 10;
+
+  jd += year / 4 - ((year / 100 + 1) *3) / 4;
+
+  return jd ;
+}
+
+/* Convert a Julian date back to YEAR, MONTH and DAY.  Return day of
+   the year or 0 on error.  This function uses some more or less
+   arbitrary limits, most important is that days before 1582 are not
+   supported. */
+static int
+jd2date (unsigned long jd, int *year, int *month, int *day)
+{
+  int y, m, d;
+  long delta;
+
+  if (!jd)
+    return 0 ;
+  if (jd < 1721425 || jd > 2843085)
+    return 0;
+
+  y = (jd - JD_DIFF) / 366;
+  d = m = 1;
+
+  while ((delta = jd - date2jd (y, m, d)) > days_per_year (y))
+    y++;
+
+  m = (delta / 31) + 1;
+  while( (delta = jd - date2jd (y, m, d)) > days_per_month (y,m))
+    if (++m > 12)
+      {
+        m = 1;
+        y++;
+      }
+
+  d = delta + 1 ;
+  if (d > days_per_month (y, m))
+    {
+      d = 1;
+      m++;
+    }
+  if (m > 12)
+    {
+      m = 1;
+      y++;
+    }
+
+  if (year)
+    *year = y;
+  if (month)
+    *month = m;
+  if (day)
+    *day = d ;
+
+  return (jd - date2jd (y, 1, 1)) + 1;
+}
+
+
+/* Check that the 15 bytes in ATIME represent a valid ISO time.  Note
+   that this function does not expect a string but a plain 15 byte
+   isotime buffer. */
+gpg_error_t
+check_isotime (const gnupg_isotime_t atime)
+{
+  int i;
+  const char *s;
+
+  if (!*atime)
+    return gpg_error (GPG_ERR_NO_VALUE);
+
+  for (s=atime, i=0; i < 8; i++, s++)
+    if (!digitp (s))
+      return gpg_error (GPG_ERR_INV_TIME);
+  if (*s != 'T')
+      return gpg_error (GPG_ERR_INV_TIME);
+  for (s++, i=9; i < 15; i++, s++)
+    if (!digitp (s))
+      return gpg_error (GPG_ERR_INV_TIME);
+  return 0;
+}
+
+
+/* Dump the ISO time T to the log stream without a LF.  */
+void
+dump_isotime (const gnupg_isotime_t t)
+{
+  if (!t || !*t)
+    log_printf ("%s", _("[none]"));
+  else
+    log_printf ("%.4s-%.2s-%.2s %.2s:%.2s:%s",
+                t, t+4, t+6, t+9, t+11, t+13);
+}
+
+
+/* Copy one ISO date to another, this is inline so that we can do a
+   minimal sanity check.  A null date (empty string) is allowed.  */
+void
+gnupg_copy_time (gnupg_isotime_t d, const gnupg_isotime_t s)
+{
+  if (*s)
+    {
+      if ((strlen (s) != 15 || s[8] != 'T'))
+        BUG();
+      memcpy (d, s, 15);
+      d[15] = 0;
+    }
+  else
+    *d = 0;
+}
+
+
+/* Add SECONDS to ATIME.  SECONDS may not be negative and is limited
+   to about the equivalent of 62 years which should be more then
+   enough for our purposes. */
+gpg_error_t
+add_seconds_to_isotime (gnupg_isotime_t atime, int nseconds)
+{
+  gpg_error_t err;
+  int year, month, day, hour, minute, sec, ndays;
+  unsigned long jd;
+
+  err = check_isotime (atime);
+  if (err)
+    return err;
+
+  if (nseconds < 0 || nseconds >= (0x7fffffff - 61) )
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  year  = atoi_4 (atime+0);
+  month = atoi_2 (atime+4);
+  day   = atoi_2 (atime+6);
+  hour  = atoi_2 (atime+9);
+  minute= atoi_2 (atime+11);
+  sec   = atoi_2 (atime+13);
+
+  if (year <= 1582) /* The julian date functions don't support this. */
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  sec    += nseconds;
+  minute += sec/60;
+  sec    %= 60;
+  hour   += minute/60;
+  minute %= 60;
+  ndays  = hour/24;
+  hour   %= 24;
+
+  jd = date2jd (year, month, day) + ndays;
+  jd2date (jd, &year, &month, &day);
+
+  if (year > 9999 || month > 12 || day > 31
+      || year < 0 || month < 1 || day < 1)
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  snprintf (atime, 16, "%04d%02d%02dT%02d%02d%02d",
+            year, month, day, hour, minute, sec);
+  return 0;
+}
+
+
+gpg_error_t
+add_days_to_isotime (gnupg_isotime_t atime, int ndays)
+{
+  gpg_error_t err;
+  int year, month, day, hour, minute, sec;
+  unsigned long jd;
+
+  err = check_isotime (atime);
+  if (err)
+    return err;
+
+  if (ndays < 0 || ndays >= 9999*366 )
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  year  = atoi_4 (atime+0);
+  month = atoi_2 (atime+4);
+  day   = atoi_2 (atime+6);
+  hour  = atoi_2 (atime+9);
+  minute= atoi_2 (atime+11);
+  sec   = atoi_2 (atime+13);
+
+  if (year <= 1582) /* The julian date functions don't support this. */
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  jd = date2jd (year, month, day) + ndays;
+  jd2date (jd, &year, &month, &day);
+
+  if (year > 9999 || month > 12 || day > 31
+      || year < 0 || month < 1 || day < 1)
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+  snprintf (atime, 16, "%04d%02d%02dT%02d%02d%02d",
+            year, month, day, hour, minute, sec);
+  return 0;
+}