5 ASN1_TIME_set, ASN1_UTCTIME_set, ASN1_GENERALIZEDTIME_set,
6 ASN1_TIME_adj, ASN1_UTCTIME_adj, ASN1_GENERALIZEDTIME_adj,
7 ASN1_TIME_check, ASN1_UTCTIME_check, ASN1_GENERALIZEDTIME_check,
8 ASN1_TIME_set_string, ASN1_UTCTIME_set_string, ASN1_GENERALIZEDTIME_set_string,
9 ASN1_TIME_set_string_X509,
12 ASN1_TIME_print, ASN1_UTCTIME_print, ASN1_GENERALIZEDTIME_print,
14 ASN1_TIME_cmp_time_t, ASN1_UTCTIME_cmp_time_t,
16 ASN1_TIME_to_generalizedtime - ASN.1 Time functions
20 ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t);
21 ASN1_UTCTIME *ASN1_UTCTIME_set(ASN1_UTCTIME *s, time_t t);
22 ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_set(ASN1_GENERALIZEDTIME *s,
25 ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t, int offset_day,
27 ASN1_UTCTIME *ASN1_UTCTIME_adj(ASN1_UTCTIME *s, time_t t,
28 int offset_day, long offset_sec);
29 ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_adj(ASN1_GENERALIZEDTIME *s,
30 time_t t, int offset_day,
33 int ASN1_TIME_set_string(ASN1_TIME *s, const char *str);
34 int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str);
35 int ASN1_UTCTIME_set_string(ASN1_UTCTIME *s, const char *str);
36 int ASN1_GENERALIZEDTIME_set_string(ASN1_GENERALIZEDTIME *s,
39 int ASN1_TIME_normalize(ASN1_TIME *s);
41 int ASN1_TIME_check(const ASN1_TIME *t);
42 int ASN1_UTCTIME_check(const ASN1_UTCTIME *t);
43 int ASN1_GENERALIZEDTIME_check(const ASN1_GENERALIZEDTIME *t);
45 int ASN1_TIME_print(BIO *b, const ASN1_TIME *s);
46 int ASN1_UTCTIME_print(BIO *b, const ASN1_UTCTIME *s);
47 int ASN1_GENERALIZEDTIME_print(BIO *b, const ASN1_GENERALIZEDTIME *s);
49 int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm);
50 int ASN1_TIME_diff(int *pday, int *psec, const ASN1_TIME *from,
53 int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t);
54 int ASN1_UTCTIME_cmp_time_t(const ASN1_UTCTIME *s, time_t t);
56 int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b);
58 ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(ASN1_TIME *t,
59 ASN1_GENERALIZEDTIME **out);
63 The ASN1_TIME_set(), ASN1_UTCTIME_set() and ASN1_GENERALIZEDTIME_set()
64 functions set the structure I<s> to the time represented by the time_t
65 value I<t>. If I<s> is NULL a new time structure is allocated and returned.
67 The ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_adj()
68 functions set the time structure I<s> to the time represented
69 by the time I<offset_day> and I<offset_sec> after the time_t value I<t>.
70 The values of I<offset_day> or I<offset_sec> can be negative to set a
71 time before I<t>. The I<offset_sec> value can also exceed the number of
72 seconds in a day. If I<s> is NULL a new structure is allocated
75 The ASN1_TIME_set_string(), ASN1_UTCTIME_set_string() and
76 ASN1_GENERALIZEDTIME_set_string() functions set the time structure I<s>
77 to the time represented by string I<str> which must be in appropriate ASN.1
78 time format (for example YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ). If I<s> is NULL
79 this function performs a format check on I<str> only. The string I<str>
82 ASN1_TIME_set_string_X509() sets B<ASN1_TIME> structure I<s> to the time
83 represented by string I<str> which must be in appropriate time format
84 that RFC 5280 requires, which means it only allows YYMMDDHHMMSSZ and
85 YYYYMMDDHHMMSSZ (leap second is rejected), all other ASN.1 time format
86 are not allowed. If I<s> is NULL this function performs a format check
89 The ASN1_TIME_normalize() function converts an B<ASN1_GENERALIZEDTIME> or
90 B<ASN1_UTCTIME> into a time value that can be used in a certificate. It
91 should be used after the ASN1_TIME_set_string() functions and before
92 ASN1_TIME_print() functions to get consistent (i.e. GMT) results.
94 The ASN1_TIME_check(), ASN1_UTCTIME_check() and ASN1_GENERALIZEDTIME_check()
95 functions check the syntax of the time structure I<s>.
97 The ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print()
98 functions print the time structure I<s> to BIO I<b> in human readable
99 format. It will be of the format MMM DD HH:MM:SS YYYY [GMT], for example
100 "Feb 3 00:55:52 2015 GMT" it does not include a newline. If the time
101 structure has invalid format it prints out "Bad time value" and returns
102 an error. The output for generalized time may include a fractional part
103 following the second.
105 ASN1_TIME_to_tm() converts the time I<s> to the standard I<tm> structure.
106 If I<s> is NULL, then the current time is converted. The output time is GMT.
107 The I<tm_sec>, I<tm_min>, I<tm_hour>, I<tm_mday>, I<tm_wday>, I<tm_yday>,
108 I<tm_mon> and I<tm_year> fields of I<tm> structure are set to proper values,
109 whereas all other fields are set to 0. If I<tm> is NULL this function performs
110 a format check on I<s> only. If I<s> is in Generalized format with fractional
111 seconds, e.g. YYYYMMDDHHMMSS.SSSZ, the fractional seconds will be lost while
112 converting I<s> to I<tm> structure.
114 ASN1_TIME_diff() sets I<*pday> and I<*psec> to the time difference between
115 I<from> and I<to>. If I<to> represents a time later than I<from> then
116 one or both (depending on the time difference) of I<*pday> and I<*psec>
117 will be positive. If I<to> represents a time earlier than I<from> then
118 one or both of I<*pday> and I<*psec> will be negative. If I<to> and I<from>
119 represent the same time then I<*pday> and I<*psec> will both be zero.
120 If both I<*pday> and I<*psec> are nonzero they will always have the same
121 sign. The value of I<*psec> will always be less than the number of seconds
122 in a day. If I<from> or I<to> is NULL the current time is used.
124 The ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() functions compare
125 the two times represented by the time structure I<s> and the time_t I<t>.
127 The ASN1_TIME_compare() function compares the two times represented by the
128 time structures I<a> and I<b>.
130 The ASN1_TIME_to_generalizedtime() function converts an B<ASN1_TIME> to an
131 B<ASN1_GENERALIZEDTIME>, regardless of year. If either I<out> or
132 I<*out> are NULL, then a new object is allocated and must be freed after use.
136 The B<ASN1_TIME> structure corresponds to the ASN.1 structure B<Time>
137 defined in RFC5280 et al. The time setting functions obey the rules outlined
138 in RFC5280: if the date can be represented by UTCTime it is used, else
139 GeneralizedTime is used.
141 The B<ASN1_TIME>, B<ASN1_UTCTIME> and B<ASN1_GENERALIZEDTIME> structures are
142 represented as an B<ASN1_STRING> internally and can be freed up using
145 The B<ASN1_TIME> structure can represent years from 0000 to 9999 but no attempt
146 is made to correct ancient calendar changes (for example from Julian to
147 Gregorian calendars).
149 B<ASN1_UTCTIME> is limited to a year range of 1950 through 2049.
151 Some applications add offset times directly to a time_t value and pass the
152 results to ASN1_TIME_set() (or equivalent). This can cause problems as the
153 time_t value can overflow on some systems resulting in unexpected results.
154 New applications should use ASN1_TIME_adj() instead and pass the offset value
155 in the I<offset_sec> and I<offset_day> parameters instead of directly
156 manipulating a time_t value.
158 ASN1_TIME_adj() may change the type from B<ASN1_GENERALIZEDTIME> to
159 B<ASN1_UTCTIME>, or vice versa, based on the resulting year.
160 ASN1_GENERALIZEDTIME_adj() and ASN1_UTCTIME_adj() will not modify the type
161 of the return structure.
163 It is recommended that functions starting with B<ASN1_TIME> be used instead of
164 those starting with B<ASN1_UTCTIME> or B<ASN1_GENERALIZEDTIME>. The functions
165 starting with B<ASN1_UTCTIME> and B<ASN1_GENERALIZEDTIME> act only on that
166 specific time format. The functions starting with B<ASN1_TIME> will operate on
171 ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print()
172 do not print out the timezone: it either prints out "GMT" or nothing. But all
173 certificates complying with RFC5280 et al use GMT anyway.
175 Use the ASN1_TIME_normalize() function to normalize the time value before
176 printing to get GMT results.
180 ASN1_TIME_set(), ASN1_UTCTIME_set(), ASN1_GENERALIZEDTIME_set(),
181 ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_set() return
182 a pointer to a time structure or NULL if an error occurred.
184 ASN1_TIME_set_string(), ASN1_UTCTIME_set_string(),
185 ASN1_GENERALIZEDTIME_set_string() and ASN1_TIME_set_string_X509() return
186 1 if the time value is successfully set and 0 otherwise.
188 ASN1_TIME_normalize() returns 1 on success, and 0 on error.
190 ASN1_TIME_check(), ASN1_UTCTIME_check and ASN1_GENERALIZEDTIME_check() return 1
191 if the structure is syntactically correct and 0 otherwise.
193 ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() return
194 1 if the time is successfully printed out and 0 if an error occurred (I/O error
195 or invalid time format).
197 ASN1_TIME_to_tm() returns 1 if the time is successfully parsed and 0 if an
198 error occurred (invalid time format).
200 ASN1_TIME_diff() returns 1 for success and 0 for failure. It can fail if the
201 passed-in time structure has invalid syntax, for example.
203 ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() return -1 if I<s> is
204 before I<t>, 0 if I<s> equals I<t>, or 1 if I<s> is after I<t>. -2 is returned
207 ASN1_TIME_compare() returns -1 if I<a> is before I<b>, 0 if I<a> equals I<b>,
208 or 1 if I<a> is after I<b>. -2 is returned on error.
210 ASN1_TIME_to_generalizedtime() returns a pointer to the appropriate time
211 structure on success or NULL if an error occurred.
215 Set a time structure to one hour after the current time and print it out:
218 #include <openssl/asn1.h>
225 tm = ASN1_TIME_adj(NULL, t, 0, 60 * 60);
226 b = BIO_new_fp(stdout, BIO_NOCLOSE);
227 ASN1_TIME_print(b, tm);
228 ASN1_STRING_free(tm);
231 Determine if one time is later or sooner than the current time:
235 if (!ASN1_TIME_diff(&day, &sec, NULL, to))
236 /* Invalid time format */
238 if (day > 0 || sec > 0)
240 else if (day < 0 || sec < 0)
247 The ASN1_TIME_to_tm() function was added in OpenSSL 1.1.1.
248 The ASN1_TIME_set_string_X509() function was added in OpenSSL 1.1.1.
249 The ASN1_TIME_normalize() function was added in OpenSSL 1.1.1.
250 The ASN1_TIME_cmp_time_t() function was added in OpenSSL 1.1.1.
251 The ASN1_TIME_compare() function was added in OpenSSL 1.1.1.
255 Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
257 Licensed under the Apache License 2.0 (the "License"). You may not use
258 this file except in compliance with the License. You can obtain a copy
259 in the file LICENSE in the source distribution or at
260 L<https://www.openssl.org/source/license.html>.