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<!-- INDEX BEGIN -->
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<p><a name="__index__"></a></p>
<ul>
<li><a href="#name">NAME</a></li>
<li><a href="#synopsis">SYNOPSIS</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<li><a href="#notes">NOTES</a></li>
<li><a href="#bugs">BUGS</a></li>
<li><a href="#return_values">RETURN VALUES</a></li>
<li><a href="#examples">EXAMPLES</a></li>
<li><a href="#history">HISTORY</a></li>
<li><a href="#copyright">COPYRIGHT</a></li>
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<p>
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<hr />
<h1><a name="name">NAME</a></h1>
<p>ASN1_TIME_set, ASN1_UTCTIME_set, ASN1_GENERALIZEDTIME_set,
ASN1_TIME_adj, ASN1_UTCTIME_adj, ASN1_GENERALIZEDTIME_adj,
ASN1_TIME_check, ASN1_UTCTIME_check, ASN1_GENERALIZEDTIME_check,
ASN1_TIME_set_string, ASN1_UTCTIME_set_string, ASN1_GENERALIZEDTIME_set_string,
ASN1_TIME_set_string_X509,
ASN1_TIME_normalize,
ASN1_TIME_to_tm,
ASN1_TIME_print, ASN1_UTCTIME_print, ASN1_GENERALIZEDTIME_print,
ASN1_TIME_diff,
ASN1_TIME_cmp_time_t, ASN1_UTCTIME_cmp_time_t,
ASN1_TIME_compare,
ASN1_TIME_to_generalizedtime - ASN.1 Time functions</p>
<p>
</p>
<hr />
<h1><a name="synopsis">SYNOPSIS</a></h1>
<pre>
ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t);
ASN1_UTCTIME *ASN1_UTCTIME_set(ASN1_UTCTIME *s, time_t t);
ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_set(ASN1_GENERALIZEDTIME *s,
time_t t);</pre>
<pre>
ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t, int offset_day,
long offset_sec);
ASN1_UTCTIME *ASN1_UTCTIME_adj(ASN1_UTCTIME *s, time_t t,
int offset_day, long offset_sec);
ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_adj(ASN1_GENERALIZEDTIME *s,
time_t t, int offset_day,
long offset_sec);</pre>
<pre>
int ASN1_TIME_set_string(ASN1_TIME *s, const char *str);
int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str);
int ASN1_UTCTIME_set_string(ASN1_UTCTIME *s, const char *str);
int ASN1_GENERALIZEDTIME_set_string(ASN1_GENERALIZEDTIME *s,
const char *str);</pre>
<pre>
int ASN1_TIME_normalize(ASN1_TIME *s);</pre>
<pre>
int ASN1_TIME_check(const ASN1_TIME *t);
int ASN1_UTCTIME_check(const ASN1_UTCTIME *t);
int ASN1_GENERALIZEDTIME_check(const ASN1_GENERALIZEDTIME *t);</pre>
<pre>
int ASN1_TIME_print(BIO *b, const ASN1_TIME *s);
int ASN1_UTCTIME_print(BIO *b, const ASN1_UTCTIME *s);
int ASN1_GENERALIZEDTIME_print(BIO *b, const ASN1_GENERALIZEDTIME *s);</pre>
<pre>
int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm);
int ASN1_TIME_diff(int *pday, int *psec, const ASN1_TIME *from,
const ASN1_TIME *to);</pre>
<pre>
int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t);
int ASN1_UTCTIME_cmp_time_t(const ASN1_UTCTIME *s, time_t t);</pre>
<pre>
int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b);</pre>
<pre>
ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(ASN1_TIME *t,
ASN1_GENERALIZEDTIME **out);</pre>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>The ASN1_TIME_set(), ASN1_UTCTIME_set() and ASN1_GENERALIZEDTIME_set()
functions set the structure <strong>s</strong> to the time represented by the time_t
value <strong>t</strong>. If <strong>s</strong> is NULL a new time structure is allocated and returned.</p>
<p>The ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_adj()
functions set the time structure <strong>s</strong> to the time represented
by the time <strong>offset_day</strong> and <strong>offset_sec</strong> after the time_t value <strong>t</strong>.
The values of <strong>offset_day</strong> or <strong>offset_sec</strong> can be negative to set a
time before <strong>t</strong>. The <strong>offset_sec</strong> value can also exceed the number of
seconds in a day. If <strong>s</strong> is NULL a new structure is allocated
and returned.</p>
<p>The ASN1_TIME_set_string(), ASN1_UTCTIME_set_string() and
ASN1_GENERALIZEDTIME_set_string() functions set the time structure <strong>s</strong>
to the time represented by string <strong>str</strong> which must be in appropriate ASN.1
time format (for example YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ). If <strong>s</strong> is NULL
this function performs a format check on <strong>str</strong> only. The string <strong>str</strong>
is copied into <strong>s</strong>.</p>
<p>ASN1_TIME_set_string_X509() sets ASN1_TIME structure <strong>s</strong> to the time
represented by string <strong>str</strong> which must be in appropriate time format
that <a href="http://www.ietf.org/rfc/rfc5280.txt" class="rfc">RFC 5280</a> requires, which means it only allows YYMMDDHHMMSSZ and
YYYYMMDDHHMMSSZ (leap second is rejected), all other ASN.1 time format
are not allowed. If <strong>s</strong> is NULL this function performs a format check
on <strong>str</strong> only.</p>
<p>The ASN1_TIME_normalize() function converts an ASN1_GENERALIZEDTIME or
ASN1_UTCTIME into a time value that can be used in a certificate. It
should be used after the ASN1_TIME_set_string() functions and before
ASN1_TIME_print() functions to get consistent (i.e. GMT) results.</p>
<p>The ASN1_TIME_check(), ASN1_UTCTIME_check() and ASN1_GENERALIZEDTIME_check()
functions check the syntax of the time structure <strong>s</strong>.</p>
<p>The ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print()
functions print the time structure <strong>s</strong> to BIO <strong>b</strong> in human readable
format. It will be of the format MMM DD HH:MM:SS YYYY [GMT], for example
"Feb 3 00:55:52 2015 GMT" it does not include a newline. If the time
structure has invalid format it prints out "Bad time value" and returns
an error. The output for generalized time may include a fractional part
following the second.</p>
<p>ASN1_TIME_to_tm() converts the time <strong>s</strong> to the standard <strong>tm</strong> structure.
If <strong>s</strong> is NULL, then the current time is converted. The output time is GMT.
The <strong>tm_sec</strong>, <strong>tm_min</strong>, <strong>tm_hour</strong>, <strong>tm_mday</strong>, <strong>tm_wday</strong>, <strong>tm_yday</strong>,
<strong>tm_mon</strong> and <strong>tm_year</strong> fields of <strong>tm</strong> structure are set to proper values,
whereas all other fields are set to 0. If <strong>tm</strong> is NULL this function performs
a format check on <strong>s</strong> only. If <strong>s</strong> is in Generalized format with fractional
seconds, e.g. YYYYMMDDHHMMSS.SSSZ, the fractional seconds will be lost while
converting <strong>s</strong> to <strong>tm</strong> structure.</p>
<p>ASN1_TIME_diff() sets <strong>*pday</strong> and <strong>*psec</strong> to the time difference between
<strong>from</strong> and <strong>to</strong>. If <strong>to</strong> represents a time later than <strong>from</strong> then
one or both (depending on the time difference) of <strong>*pday</strong> and <strong>*psec</strong>
will be positive. If <strong>to</strong> represents a time earlier than <strong>from</strong> then
one or both of <strong>*pday</strong> and <strong>*psec</strong> will be negative. If <strong>to</strong> and <strong>from</strong>
represent the same time then <strong>*pday</strong> and <strong>*psec</strong> will both be zero.
If both <strong>*pday</strong> and <strong>*psec</strong> are nonzero they will always have the same
sign. The value of <strong>*psec</strong> will always be less than the number of seconds
in a day. If <strong>from</strong> or <strong>to</strong> is NULL the current time is used.</p>
<p>The ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() functions compare
the two times represented by the time structure <strong>s</strong> and the time_t <strong>t</strong>.</p>
<p>The ASN1_TIME_compare() function compares the two times represented by the
time structures <strong>a</strong> and <strong>b</strong>.</p>
<p>The ASN1_TIME_to_generalizedtime() function converts an ASN1_TIME to an
ASN1_GENERALIZEDTIME, regardless of year. If either <strong>out</strong> or
<strong>*out</strong> are NULL, then a new object is allocated and must be freed after use.</p>
<p>
</p>
<hr />
<h1><a name="notes">NOTES</a></h1>
<p>The ASN1_TIME structure corresponds to the ASN.1 structure <strong>Time</strong>
defined in <a href="http://www.ietf.org/rfc/rfc5280.txt" class="rfc">RFC5280</a> et al. The time setting functions obey the rules outlined
in <a href="http://www.ietf.org/rfc/rfc5280.txt" class="rfc">RFC5280</a>: if the date can be represented by UTCTime it is used, else
GeneralizedTime is used.</p>
<p>The ASN1_TIME, ASN1_UTCTIME and ASN1_GENERALIZEDTIME structures are represented
as an ASN1_STRING internally and can be freed up using ASN1_STRING_free().</p>
<p>The ASN1_TIME structure can represent years from 0000 to 9999 but no attempt
is made to correct ancient calendar changes (for example from Julian to
Gregorian calendars).</p>
<p>ASN1_UTCTIME is limited to a year range of 1950 through 2049.</p>
<p>Some applications add offset times directly to a time_t value and pass the
results to ASN1_TIME_set() (or equivalent). This can cause problems as the
time_t value can overflow on some systems resulting in unexpected results.
New applications should use ASN1_TIME_adj() instead and pass the offset value
in the <strong>offset_sec</strong> and <strong>offset_day</strong> parameters instead of directly
manipulating a time_t value.</p>
<p>ASN1_TIME_adj() may change the type from ASN1_GENERALIZEDTIME to ASN1_UTCTIME,
or vice versa, based on the resulting year. The ASN1_GENERALIZEDTIME_adj() and
ASN1_UTCTIME_adj() functions will not modify the type of the return structure.</p>
<p>It is recommended that functions starting with ASN1_TIME be used instead of
those starting with ASN1_UTCTIME or ASN1_GENERALIZEDTIME. The functions
starting with ASN1_UTCTIME and ASN1_GENERALIZEDTIME act only on that specific
time format. The functions starting with ASN1_TIME will operate on either
format.</p>
<p>
</p>
<hr />
<h1><a name="bugs">BUGS</a></h1>
<p>ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print()
do not print out the timezone: it either prints out "GMT" or nothing. But all
certificates complying with <a href="http://www.ietf.org/rfc/rfc5280.txt" class="rfc">RFC5280</a> et al use GMT anyway.</p>
<p>Use the ASN1_TIME_normalize() function to normalize the time value before
printing to get GMT results.</p>
<p>
</p>
<hr />
<h1><a name="return_values">RETURN VALUES</a></h1>
<p>ASN1_TIME_set(), ASN1_UTCTIME_set(), ASN1_GENERALIZEDTIME_set(), ASN1_TIME_adj(),
ASN1_UTCTIME_adj and ASN1_GENERALIZEDTIME_set return a pointer to a time structure
or NULL if an error occurred.</p>
<p>ASN1_TIME_set_string(), ASN1_UTCTIME_set_string(), ASN1_GENERALIZEDTIME_set_string()
ASN1_TIME_set_string_X509() return 1 if the time value is successfully set and 0 otherwise.</p>
<p>ASN1_TIME_normalize() returns 1 on success, and 0 on error.</p>
<p>ASN1_TIME_check(), ASN1_UTCTIME_check and ASN1_GENERALIZEDTIME_check() return 1
if the structure is syntactically correct and 0 otherwise.</p>
<p>ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() return 1
if the time is successfully printed out and 0 if an error occurred (I/O error or
invalid time format).</p>
<p>ASN1_TIME_to_tm() returns 1 if the time is successfully parsed and 0 if an
error occurred (invalid time format).</p>
<p>ASN1_TIME_diff() returns 1 for success and 0 for failure. It can fail if the
passed-in time structure has invalid syntax, for example.</p>
<p>ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() return -1 if <strong>s</strong> is
before <strong>t</strong>, 0 if <strong>s</strong> equals <strong>t</strong>, or 1 if <strong>s</strong> is after <strong>t</strong>. -2 is returned
on error.</p>
<p>ASN1_TIME_compare() returns -1 if <strong>a</strong> is before <strong>b</strong>, 0 if <strong>a</strong> equals <strong>b</strong>, or 1 if <strong>a</strong> is after <strong>b</strong>. -2 is returned on error.</p>
<p>ASN1_TIME_to_generalizedtime() returns a pointer to
the appropriate time structure on success or NULL if an error occurred.</p>
<p>
</p>
<hr />
<h1><a name="examples">EXAMPLES</a></h1>
<p>Set a time structure to one hour after the current time and print it out:</p>
<pre>
#include <time.h>
#include <openssl/asn1.h></pre>
<pre>
ASN1_TIME *tm;
time_t t;
BIO *b;</pre>
<pre>
t = time(NULL);
tm = ASN1_TIME_adj(NULL, t, 0, 60 * 60);
b = BIO_new_fp(stdout, BIO_NOCLOSE);
ASN1_TIME_print(b, tm);
ASN1_STRING_free(tm);
BIO_free(b);</pre>
<p>Determine if one time is later or sooner than the current time:</p>
<pre>
int day, sec;</pre>
<pre>
if (!ASN1_TIME_diff(&day, &sec, NULL, to))
/* Invalid time format */</pre>
<pre>
if (day > 0 || sec > 0)
printf("Later\n");
else if (day < 0 || sec < 0)
printf("Sooner\n");
else
printf("Same\n");</pre>
<p>
</p>
<hr />
<h1><a name="history">HISTORY</a></h1>
<p>The ASN1_TIME_to_tm() function was added in OpenSSL 1.1.1.
The ASN1_TIME_set_string_X509() function was added in OpenSSL 1.1.1.
The ASN1_TIME_normalize() function was added in OpenSSL 1.1.1.
The ASN1_TIME_cmp_time_t() function was added in OpenSSL 1.1.1.
The ASN1_TIME_compare() function was added in OpenSSL 1.1.1.</p>
<p>
</p>
<hr />
<h1><a name="copyright">COPYRIGHT</a></h1>
<p>Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.</p>
<p>Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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