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date,touch: allow timezone offsets in dates

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Allow ISO 8601 style dates to include a timezone offset.  Like
the '@' format these dates aren't relative to the user's current
timezone and shouldn't be subject to DST adjustment.

- The implementation uses the strptime() '%z' format specifier.
  This an extension which may not be available so the use of
  timezones is a configuration option.

- The 'touch' applet has been updated to respect whether DST
  adjustment is required, matching 'date'.

function                                             old     new   delta
parse_datestr                                        624     730    +106
static.fmt_str                                       106     136     +30
touch_main                                           388     392      +4
date_main                                            818     819      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 141/0)             Total: 141 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2021-09-16 10:26:14 +01:00 committed by Denys Vlasenko
parent 83e20cb81c
commit 9fe1548bbf
6 changed files with 83 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
coreutils/date.c
View File

@ -266,6 +266,7 @@ int date_main(int argc UNUSED_PARAM, char **argv)
/* If date string is given, update tm_time, and maybe set date */
if (date_str != NULL) {
int check_dst = 1;
/* Zero out fields - take her back to midnight! */
tm_time.tm_sec = 0;
tm_time.tm_min = 0;
@ -276,12 +277,12 @@ int date_main(int argc UNUSED_PARAM, char **argv)
if (strptime(date_str, fmt_str2dt, &tm_time) == NULL)
bb_error_msg_and_die(bb_msg_invalid_date, date_str);
} else {
parse_datestr(date_str, &tm_time);
check_dst = parse_datestr(date_str, &tm_time);
}
/* Correct any day of week and day of year etc. fields */
/* Be sure to recheck dst (but not if date is time_t format) */
if (date_str[0] != '@')
/* Be sure to recheck dst (but not if date is UTC) */
if (check_dst)
tm_time.tm_isdst = -1;
ts.tv_sec = validate_tm_time(date_str, &tm_time);
ts.tv_nsec = 0;

6
coreutils/touch.c
View File

@ -140,15 +140,17 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
if (opts & (OPT_d|OPT_t)) {
struct tm tm_time;
time_t t;
int check_dst;
//memset(&tm_time, 0, sizeof(tm_time));
/* Better than memset: makes "HH:MM" dates meaningful */
time(&t);
localtime_r(&t, &tm_time);
parse_datestr(date_str, &tm_time);
check_dst = parse_datestr(date_str, &tm_time);
/* Correct any day of week and day of year etc. fields */
tm_time.tm_isdst = -1; /* Be sure to recheck dst */
if (check_dst)
tm_time.tm_isdst = -1; /* recheck dst unless date is UTC */
t = validate_tm_time(date_str, &tm_time);
timebuf[1].tv_sec = timebuf[0].tv_sec = t;

2
include/libbb.h
View File

@ -690,7 +690,7 @@ struct BUG_too_small {
};
void parse_datestr(const char *date_str, struct tm *ptm) FAST_FUNC;
int parse_datestr(const char *date_str, struct tm *ptm) FAST_FUNC;
time_t validate_tm_time(const char *date_str, struct tm *ptm) FAST_FUNC;
char *strftime_HHMMSS(char *buf, unsigned len, time_t *tp) FAST_FUNC;
char *strftime_YYYYMMDDHHMMSS(char *buf, unsigned len, time_t *tp) FAST_FUNC;

11
libbb/Config.src
View File

@ -395,3 +395,14 @@ config FEATURE_HWIB
default y
help
Support for printing infiniband addresses in network applets.
config FEATURE_TIMEZONE
bool "Allow timezone in dates"
default y
depends on DESKTOP
help
Permit the use of timezones when parsing user-provided data
strings, e.g. '1996-04-09 12:45:00 -0500'.
This requires support for the '%z' extension to strptime() which
may not be available in all implementations.

35
libbb/time.c
View File

@ -8,7 +8,9 @@
*/
#include "libbb.h"
void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
/* Returns 0 if the time structure contains an absolute UTC time which
* should not be subject to DST adjustment by the caller. */
int FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
{
char end = '\0';
#if ENABLE_DESKTOP
@ -27,6 +29,10 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
"%b %d %T %Y" "\0" /* month_name d HH:MM:SS YYYY */
"%Y-%m-%d %R" "\0" /* yyyy-mm-dd HH:MM */
"%Y-%m-%d %T" "\0" /* yyyy-mm-dd HH:MM:SS */
#if ENABLE_FEATURE_TIMEZONE
"%Y-%m-%d %R %z" "\0" /* yyyy-mm-dd HH:MM TZ */
"%Y-%m-%d %T %z" "\0" /* yyyy-mm-dd HH:MM:SS TZ */
#endif
"%Y-%m-%d %H" "\0" /* yyyy-mm-dd HH */
"%Y-%m-%d" "\0" /* yyyy-mm-dd */
/* extra NUL */;
@ -38,8 +44,28 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
fmt = fmt_str;
while (*fmt) {
endp = strptime(date_str, fmt, ptm);
if (endp && *endp == '\0')
return;
if (endp && *endp == '\0') {
#if ENABLE_FEATURE_TIMEZONE
if (strchr(fmt, 'z')) {
time_t t;
struct tm *utm;
/* we have timezone offset: obtain Unix time_t */
ptm->tm_sec -= ptm->tm_gmtoff;
ptm->tm_isdst = 0;
t = timegm(ptm);
if (t == (time_t)-1)
break;
/* convert Unix time_t to struct tm in user's locale */
utm = localtime(&t);
if (!utm)
break;
*ptm = *utm;
return 0;
}
#endif
return 1;
}
*ptm = save;
while (*++fmt)
continue;
@ -124,7 +150,7 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
struct tm *lt = localtime(&t);
if (lt) {
*ptm = *lt;
return;
return 0;
}
}
end = '1';
@ -241,6 +267,7 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
if (end != '\0') {
bb_error_msg_and_die(bb_msg_invalid_date, date_str);
}
return 1;
}
time_t FAST_FUNC validate_tm_time(const char *date_str, struct tm *ptm)

32
testsuite/date/date-timezone Normal file
View File

@ -0,0 +1,32 @@
# FEATURE: CONFIG_FEATURE_TIMEZONE
# 'Z' is UTC
dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5Z')
dt=$(echo "$dt" | cut -b1-19)
test x"$dt" = x"Sat Jan 2 03:04:05"
# '+0600' is six hours ahead of UTC
dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5 +0600')
dt=$(echo "$dt" | cut -b1-19)
test x"$dt" = x"Fri Jan 1 21:04:05"
# '-0600' is six hours behind UTC
dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5 -0600')
dt=$(echo "$dt" | cut -b1-19)
test x"$dt" = x"Sat Jan 2 09:04:05"
# before dst is switched on
dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-03-28 00:59:59 +0000')
test x"$dt" = x"Sun Mar 28 00:59:59 GMT 2021"
# after dst is switched on
dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-03-28 01:00:01 +0000')
test x"$dt" = x"Sun Mar 28 02:00:01 BST 2021"
# before dst is switched off
dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-10-31 00:00:01 +0000')
test x"$dt" = x"Sun Oct 31 01:00:01 BST 2021"
# after dst is switched off: back to 01:00:01 but with different TZ
dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-10-31 01:00:01 +0000')
test x"$dt" = x"Sun Oct 31 01:00:01 GMT 2021"