gnupg/common/gettime.c

994 lines
23 KiB
C

/* 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_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 = current;
}
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 || (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" 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;
}
/****************
* Note: this function returns local time
*/
const char *
asctimestamp (u32 stamp)
{
static char buffer[50];
#if defined (HAVE_STRFTIME) && defined (HAVE_NL_LANGINFO)
static char fmt[50];
#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
/* 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;
}