1ASN1_TIME_SET(3ossl)                OpenSSL               ASN1_TIME_SET(3ossl)
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NAME

6       ASN1_TIME_set, ASN1_UTCTIME_set, ASN1_GENERALIZEDTIME_set,
7       ASN1_TIME_adj, ASN1_UTCTIME_adj, ASN1_GENERALIZEDTIME_adj,
8       ASN1_TIME_check, ASN1_UTCTIME_check, ASN1_GENERALIZEDTIME_check,
9       ASN1_TIME_set_string, ASN1_UTCTIME_set_string,
10       ASN1_GENERALIZEDTIME_set_string, ASN1_TIME_set_string_X509,
11       ASN1_TIME_normalize, ASN1_TIME_to_tm, ASN1_TIME_print,
12       ASN1_TIME_print_ex, ASN1_UTCTIME_print, ASN1_GENERALIZEDTIME_print,
13       ASN1_TIME_diff, ASN1_TIME_cmp_time_t, ASN1_UTCTIME_cmp_time_t,
14       ASN1_TIME_compare, ASN1_TIME_to_generalizedtime, ASN1_TIME_dup,
15       ASN1_UTCTIME_dup, ASN1_GENERALIZEDTIME_dup - ASN.1 Time functions
16

SYNOPSIS

18        ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t);
19        ASN1_UTCTIME *ASN1_UTCTIME_set(ASN1_UTCTIME *s, time_t t);
20        ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_set(ASN1_GENERALIZEDTIME *s,
21                                                       time_t t);
22
23        ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t, int offset_day,
24                                 long offset_sec);
25        ASN1_UTCTIME *ASN1_UTCTIME_adj(ASN1_UTCTIME *s, time_t t,
26                                       int offset_day, long offset_sec);
27        ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_adj(ASN1_GENERALIZEDTIME *s,
28                                                       time_t t, int offset_day,
29                                                       long offset_sec);
30
31        int ASN1_TIME_set_string(ASN1_TIME *s, const char *str);
32        int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str);
33        int ASN1_UTCTIME_set_string(ASN1_UTCTIME *s, const char *str);
34        int ASN1_GENERALIZEDTIME_set_string(ASN1_GENERALIZEDTIME *s,
35                                            const char *str);
36
37        int ASN1_TIME_normalize(ASN1_TIME *s);
38
39        int ASN1_TIME_check(const ASN1_TIME *t);
40        int ASN1_UTCTIME_check(const ASN1_UTCTIME *t);
41        int ASN1_GENERALIZEDTIME_check(const ASN1_GENERALIZEDTIME *t);
42
43        int ASN1_TIME_print(BIO *b, const ASN1_TIME *s);
44        int ASN1_TIME_print_ex(BIO *bp, const ASN1_TIME *tm, unsigned long flags);
45        int ASN1_UTCTIME_print(BIO *b, const ASN1_UTCTIME *s);
46        int ASN1_GENERALIZEDTIME_print(BIO *b, const ASN1_GENERALIZEDTIME *s);
47
48        int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm);
49        int ASN1_TIME_diff(int *pday, int *psec, const ASN1_TIME *from,
50                           const ASN1_TIME *to);
51
52        int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t);
53        int ASN1_UTCTIME_cmp_time_t(const ASN1_UTCTIME *s, time_t t);
54
55        int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b);
56
57        ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(ASN1_TIME *t,
58                                                           ASN1_GENERALIZEDTIME **out);
59
60        ASN1_TIME *ASN1_TIME_dup(const ASN1_TIME *t);
61        ASN1_UTCTIME *ASN1_UTCTIME_dup(const ASN1_UTCTIME *t);
62        ASN1_GENERALIZEDTIME *ASN1_GENERALIZEDTIME_dup(const ASN1_GENERALIZEDTIME *t);
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DESCRIPTION

65       The ASN1_TIME_set(), ASN1_UTCTIME_set() and ASN1_GENERALIZEDTIME_set()
66       functions set the structure s to the time represented by the time_t
67       value t. If s is NULL a new time structure is allocated and returned.
68
69       The ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_adj()
70       functions set the time structure s to the time represented by the time
71       offset_day and offset_sec after the time_t value t.  The values of
72       offset_day or offset_sec can be negative to set a time before t. The
73       offset_sec value can also exceed the number of seconds in a day. If s
74       is NULL a new structure is allocated and returned.
75
76       The ASN1_TIME_set_string(), ASN1_UTCTIME_set_string() and
77       ASN1_GENERALIZEDTIME_set_string() functions set the time structure s to
78       the time represented by string str which must be in appropriate ASN.1
79       time format (for example YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ). If s is
80       NULL this function performs a format check on str only. The string str
81       is copied into s.
82
83       ASN1_TIME_set_string_X509() sets ASN1_TIME structure s to the time
84       represented by string str which must be in appropriate time format that
85       RFC 5280 requires, which means it only allows YYMMDDHHMMSSZ and
86       YYYYMMDDHHMMSSZ (leap second is rejected), all other ASN.1 time format
87       are not allowed. If s is NULL this function performs a format check on
88       str only.
89
90       The ASN1_TIME_normalize() function converts an ASN1_GENERALIZEDTIME or
91       ASN1_UTCTIME into a time value that can be used in a certificate. It
92       should be used after the ASN1_TIME_set_string() functions and before
93       ASN1_TIME_print() functions to get consistent (i.e. GMT) results.
94
95       The ASN1_TIME_check(), ASN1_UTCTIME_check() and
96       ASN1_GENERALIZEDTIME_check() functions check the syntax of the time
97       structure s.
98
99       The ASN1_TIME_print(), ASN1_UTCTIME_print() and
100       ASN1_GENERALIZEDTIME_print() functions print the time structure s to
101       BIO b in human readable format. It will be of the format MMM DD
102       HH:MM:SS YYYY [GMT], for example "Feb  3 00:55:52 2015 GMT", which does
103       not include a newline.  If the time structure has invalid format it
104       prints out "Bad time value" and returns an error. The output for
105       generalized time may include a fractional part following the second.
106
107       ASN1_TIME_print_ex() provides flags to specify the output format of the
108       datetime. This can be either ASN1_DTFLGS_RFC822 or ASN1_DTFLGS_ISO8601.
109
110       ASN1_TIME_to_tm() converts the time s to the standard tm structure.  If
111       s is NULL, then the current time is converted. The output time is GMT.
112       The tm_sec, tm_min, tm_hour, tm_mday, tm_wday, tm_yday, tm_mon and
113       tm_year fields of tm structure are set to proper values, whereas all
114       other fields are set to 0. If tm is NULL this function performs a
115       format check on s only. If s is in Generalized format with fractional
116       seconds, e.g. YYYYMMDDHHMMSS.SSSZ, the fractional seconds will be lost
117       while converting s to tm structure.
118
119       ASN1_TIME_diff() sets *pday and *psec to the time difference between
120       from and to. If to represents a time later than from then one or both
121       (depending on the time difference) of *pday and *psec will be positive.
122       If to represents a time earlier than from then one or both of *pday and
123       *psec will be negative. If to and from represent the same time then
124       *pday and *psec will both be zero.  If both *pday and *psec are nonzero
125       they will always have the same sign. The value of *psec will always be
126       less than the number of seconds in a day. If from or to is NULL the
127       current time is used.
128
129       The ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() functions
130       compare the two times represented by the time structure s and the
131       time_t t.
132
133       The ASN1_TIME_compare() function compares the two times represented by
134       the time structures a and b.
135
136       The ASN1_TIME_to_generalizedtime() function converts an ASN1_TIME to an
137       ASN1_GENERALIZEDTIME, regardless of year. If either out or *out are
138       NULL, then a new object is allocated and must be freed after use.
139
140       The ASN1_TIME_dup(), ASN1_UTCTIME_dup() and ASN1_GENERALIZEDTIME_dup()
141       functions duplicate the time structure t and return the duplicated
142       result correspondingly.
143

NOTES

145       The ASN1_TIME structure corresponds to the ASN.1 structure Time defined
146       in RFC5280 et al. The time setting functions obey the rules outlined in
147       RFC5280: if the date can be represented by UTCTime it is used, else
148       GeneralizedTime is used.
149
150       The ASN1_TIME, ASN1_UTCTIME and ASN1_GENERALIZEDTIME structures are
151       represented as an ASN1_STRING internally and can be freed up using
152       ASN1_STRING_free().
153
154       The ASN1_TIME structure can represent years from 0000 to 9999 but no
155       attempt is made to correct ancient calendar changes (for example from
156       Julian to Gregorian calendars).
157
158       ASN1_UTCTIME is limited to a year range of 1950 through 2049.
159
160       Some applications add offset times directly to a time_t value and pass
161       the results to ASN1_TIME_set() (or equivalent). This can cause problems
162       as the time_t value can overflow on some systems resulting in
163       unexpected results.  New applications should use ASN1_TIME_adj()
164       instead and pass the offset value in the offset_sec and offset_day
165       parameters instead of directly manipulating a time_t value.
166
167       ASN1_TIME_adj() may change the type from ASN1_GENERALIZEDTIME to
168       ASN1_UTCTIME, or vice versa, based on the resulting year.
169       ASN1_GENERALIZEDTIME_adj() and ASN1_UTCTIME_adj() will not modify the
170       type of the return structure.
171
172       It is recommended that functions starting with ASN1_TIME be used
173       instead of those starting with ASN1_UTCTIME or ASN1_GENERALIZEDTIME.
174       The functions starting with ASN1_UTCTIME and ASN1_GENERALIZEDTIME act
175       only on that specific time format. The functions starting with
176       ASN1_TIME will operate on either format.
177

BUGS

179       ASN1_TIME_print(), ASN1_UTCTIME_print() and
180       ASN1_GENERALIZEDTIME_print() do not print out the timezone: it either
181       prints out "GMT" or nothing. But all certificates complying with
182       RFC5280 et al use GMT anyway.
183
184       ASN1_TIME_print(), ASN1_TIME_print_ex(), ASN1_UTCTIME_print() and
185       ASN1_GENERALIZEDTIME_print() do not distinguish if they fail because of
186       an I/O error or invalid time format.
187
188       Use the ASN1_TIME_normalize() function to normalize the time value
189       before printing to get GMT results.
190

RETURN VALUES

192       ASN1_TIME_set(), ASN1_UTCTIME_set(), ASN1_GENERALIZEDTIME_set(),
193       ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_set()
194       return a pointer to a time structure or NULL if an error occurred.
195
196       ASN1_TIME_set_string(), ASN1_UTCTIME_set_string(),
197       ASN1_GENERALIZEDTIME_set_string() and ASN1_TIME_set_string_X509()
198       return 1 if the time value is successfully set and 0 otherwise.
199
200       ASN1_TIME_normalize() returns 1 on success, and 0 on error.
201
202       ASN1_TIME_check(), ASN1_UTCTIME_check and ASN1_GENERALIZEDTIME_check()
203       return 1 if the structure is syntactically correct and 0 otherwise.
204
205       ASN1_TIME_print(), ASN1_UTCTIME_print() and
206       ASN1_GENERALIZEDTIME_print() return 1 if the time is successfully
207       printed out and 0 if an I/O error occurred an error occurred (I/O error
208       or invalid time format).
209
210       ASN1_TIME_to_tm() returns 1 if the time is successfully parsed and 0 if
211       an error occurred (invalid time format).
212
213       ASN1_TIME_diff() returns 1 for success and 0 for failure. It can fail
214       if the passed-in time structure has invalid syntax, for example.
215
216       ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() return -1 if s is
217       before t, 0 if s equals t, or 1 if s is after t. -2 is returned on
218       error.
219
220       ASN1_TIME_compare() returns -1 if a is before b, 0 if a equals b, or 1
221       if a is after b. -2 is returned on error.
222
223       ASN1_TIME_to_generalizedtime() returns a pointer to the appropriate
224       time structure on success or NULL if an error occurred.
225
226       ASN1_TIME_dup(), ASN1_UTCTIME_dup() and ASN1_GENERALIZEDTIME_dup()
227       return a pointer to a time structure or NULL if an error occurred.
228

EXAMPLES

230       Set a time structure to one hour after the current time and print it
231       out:
232
233        #include <time.h>
234        #include <openssl/asn1.h>
235
236        ASN1_TIME *tm;
237        time_t t;
238        BIO *b;
239
240        t = time(NULL);
241        tm = ASN1_TIME_adj(NULL, t, 0, 60 * 60);
242        b = BIO_new_fp(stdout, BIO_NOCLOSE);
243        ASN1_TIME_print(b, tm);
244        ASN1_STRING_free(tm);
245        BIO_free(b);
246
247       Determine if one time is later or sooner than the current time:
248
249        int day, sec;
250
251        if (!ASN1_TIME_diff(&day, &sec, NULL, to))
252            /* Invalid time format */
253
254        if (day > 0 || sec > 0)
255            printf("Later\n");
256        else if (day < 0 || sec < 0)
257            printf("Sooner\n");
258        else
259            printf("Same\n");
260

HISTORY

262       The ASN1_TIME_to_tm() function was added in OpenSSL 1.1.1.  The
263       ASN1_TIME_set_string_X509() function was added in OpenSSL 1.1.1.  The
264       ASN1_TIME_normalize() function was added in OpenSSL 1.1.1.  The
265       ASN1_TIME_cmp_time_t() function was added in OpenSSL 1.1.1.  The
266       ASN1_TIME_compare() function was added in OpenSSL 1.1.1.
267
269       Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.
270
271       Licensed under the Apache License 2.0 (the "License").  You may not use
272       this file except in compliance with the License.  You can obtain a copy
273       in the file LICENSE in the source distribution or at
274       <https://www.openssl.org/source/license.html>.
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2783.0.5                             2022-07-05              ASN1_TIME_SET(3ossl)
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