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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
commit | 5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch) | |
tree | 2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /src/global/mail_date.c | |
parent | Initial commit. (diff) | |
download | postfix-upstream/3.5.24.tar.xz postfix-upstream/3.5.24.zip |
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/global/mail_date.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/global/mail_date.c b/src/global/mail_date.c new file mode 100644 index 0000000..55d8907 --- /dev/null +++ b/src/global/mail_date.c @@ -0,0 +1,141 @@ +/*++ +/* NAME +/* mail_date 3 +/* SUMMARY +/* return formatted time +/* SYNOPSIS +/* #include <mail_date.h> +/* +/* const char *mail_date(when) +/* time_t when; +/* DESCRIPTION +/* mail_date() converts the time specified in \fIwhen\fR to the +/* form: "Mon, 9 Dec 1996 05:38:26 -0500 (EST)" and returns +/* a pointer to the result. The result is overwritten upon +/* each call. +/* DIAGNOSTICS +/* Panic: the offset from UTC is more than a whole day. Fatal +/* error: out of memory. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <time.h> +#include <stdlib.h> + +/* Utility library. */ + +#include <msg.h> +#include <vstring.h> + +/* Global library. */ + +#include "mail_date.h" + + /* + * Application-specific. + */ +#define DAY_MIN (24 * HOUR_MIN) /* minutes in a day */ +#define HOUR_MIN 60 /* minutes in an hour */ +#define MIN_SEC 60 /* seconds in a minute */ + +/* mail_date - return formatted time */ + +const char *mail_date(time_t when) +{ + static VSTRING *vp; + struct tm *lt; + struct tm gmt; + int gmtoff; + + /* + * As if strftime() isn't expensive enough, we're dynamically adjusting + * the size for the result, so we won't be surprised by long names etc. + */ + if (vp == 0) + vp = vstring_alloc(100); + else + VSTRING_RESET(vp); + + /* + * POSIX does not require that struct tm has a tm_gmtoff field, so we + * must compute the time offset from UTC by hand. + * + * Starting with the difference in hours/minutes between 24-hour clocks, + * adjust for differences in years, in yeardays, and in (leap) seconds. + * + * Assume 0..23 hours in a day, 0..59 minutes in an hour. The library spec + * has changed: we can no longer assume that there are 0..59 seconds in a + * minute. + */ + gmt = *gmtime(&when); + lt = localtime(&when); + gmtoff = (lt->tm_hour - gmt.tm_hour) * HOUR_MIN + lt->tm_min - gmt.tm_min; + if (lt->tm_year < gmt.tm_year) + gmtoff -= DAY_MIN; + else if (lt->tm_year > gmt.tm_year) + gmtoff += DAY_MIN; + else if (lt->tm_yday < gmt.tm_yday) + gmtoff -= DAY_MIN; + else if (lt->tm_yday > gmt.tm_yday) + gmtoff += DAY_MIN; + if (lt->tm_sec <= gmt.tm_sec - MIN_SEC) + gmtoff -= 1; + else if (lt->tm_sec >= gmt.tm_sec + MIN_SEC) + gmtoff += 1; + + /* + * First, format the date and wall-clock time. XXX The %e format (day of + * month, leading zero replaced by blank) isn't in my POSIX book, but + * many vendors seem to support it. + */ +#ifdef MISSING_STRFTIME_E +#define STRFTIME_FMT "%a, %d %b %Y %H:%M:%S " +#else +#define STRFTIME_FMT "%a, %e %b %Y %H:%M:%S " +#endif + + while (strftime(vstring_end(vp), vstring_avail(vp), STRFTIME_FMT, lt) == 0) + VSTRING_SPACE(vp, 100); + VSTRING_SKIP(vp); + + /* + * Then, add the UTC offset. + */ + if (gmtoff < -DAY_MIN || gmtoff > DAY_MIN) + msg_panic("UTC time offset %d is larger than one day", gmtoff); + vstring_sprintf_append(vp, "%+03d%02d", (int) (gmtoff / HOUR_MIN), + (int) (abs(gmtoff) % HOUR_MIN)); + + /* + * Finally, add the time zone name. + */ + while (strftime(vstring_end(vp), vstring_avail(vp), " (%Z)", lt) == 0) + VSTRING_SPACE(vp, vstring_avail(vp) + 100); + VSTRING_SKIP(vp); + + return (vstring_str(vp)); +} + +#ifdef TEST + +#include <vstream.h> + +int main(void) +{ + vstream_printf("%s\n", mail_date(time((time_t *) 0))); + vstream_fflush(VSTREAM_OUT); + return (0); +} + +#endif |