hwclock: improve --help (-l is a compatible shortcut for --localtime)

function                                             old     new   delta
packed_usage                                       33605   33568     -37

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2020-12-16 20:55:30 +01:00
parent 9e262f13c2
commit d3c36882dc

View File

@ -153,14 +153,12 @@ static void set_kernel_tz(const struct timezone *tz)
* then system time is wrong - it is offset by timezone.
* --systz option corrects system time if RTC is in local time,
* and (always) sets in-kernel timezone.
*
* This is an alternate option to --hctosys that does not read the
* hardware clock.
* (Unlike --hctosys, it does not read the RTC).
*
* util-linux's code has this comment:
* RTC | settimeofday calls
* ------|-------------------------------------------------
* Local | 1) warps system time*, sets PCIL* and kernel tz
* Local | 1st) warps system time*, sets PCIL* and kernel tz
* UTC | 1st) locks warp_clock 2nd) sets kernel tz
* * only on first call after boot
* (PCIL is "persistent_clock_is_local" kernel internal flag,
@ -177,6 +175,9 @@ static void set_kernel_timezone_and_clock(int utc, const struct timeval *hctosys
set_kernel_tz(&tz);
/* Set kernel's timezone offset based on userspace one */
//It's tempting to call tzset() and use libc global "timezone" variable
//...but it does NOT include DST shift (IOW: it's WRONG, usually by one hour,
//if DST is in effect!) Thus this ridiculous dance:
cur = time(NULL);
broken = localtime(&cur);
tz.tz_minuteswest = -broken->tm_gmtoff / 60;
@ -321,30 +322,58 @@ static void from_sys_clock(const char **pp_rtcname, int utc)
close(rtc);
}
// hwclock from util-linux 2.36.1
// hwclock [function] [option...]
//Functions:
// -r, --show display the RTC time
// --get display drift corrected RTC time
// --set set the RTC according to --date
// -s, --hctosys set the system time from the RTC
// -w, --systohc set the RTC from the system time
// --systz send timescale configurations to the kernel
// -a, --adjust adjust the RTC to account for systematic drift
// --predict predict the drifted RTC time according to --date
//Options:
// -u, --utc the RTC timescale is UTC
// -l, --localtime the RTC timescale is Local
// -f, --rtc <file> use an alternate file to /dev/rtc0
// --directisa use the ISA bus instead of /dev/rtc0 access
// --date <time> date/time input for --set and --predict
// --delay <sec> delay used when set new RTC time
// --update-drift update the RTC drift factor
// --noadjfile do not use /etc/adjtime
// --adjfile <file> use an alternate file to /etc/adjtime
// --test dry run; implies --verbose
// -v, --verbose display more details
//usage:#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
//usage:# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
//usage:#else
//usage:# define ADJTIME_PATH "/etc/adjtime"
//usage:#endif
//usage:#define hwclock_trivial_usage
//usage: IF_LONG_OPTS(
//usage: "[-swu] [--systz] [--localtime] [-f FILE]"
//usage: "[-swul] [--systz] [-f DEV]"
//usage: )
//usage: IF_NOT_LONG_OPTS(
//usage: "[-swtlu] [-f FILE]"
//usage: "[-swult] [-f DEV]"
//usage: )
//usage:#define hwclock_full_usage "\n\n"
//usage: "Show or set hardware clock (RTC)\n"
///////: "\n -r Show hardware clock time"
///////: "\n -r Show RTC time"
///////-r is default, don't bother showing it in help
//usage: "\n -s Set system time from hardware clock"
//usage: "\n -w Set hardware clock from system time"
//usage: "\n -s Set system time from RTC"
//usage: "\n -w Set RTC from system time"
//usage: IF_LONG_OPTS(
//usage: "\n --systz Set in-kernel timezone, correct system time"
//usage: "\n if RTC is kept in local time"
//usage: )
//usage: "\n if hardware clock is in local time"
//usage: "\n -u Assume hardware clock is kept in UTC"
//usage: IF_LONG_OPTS(
//usage: "\n --localtime Assume hardware clock is kept in local time"
//usage: )
//usage: "\n -f FILE Use specified device (e.g. /dev/rtc2)"
//usage: "\n -f DEV Use specified device (e.g. /dev/rtc2)"
//usage: "\n -u Assume RTC is kept in UTC"
//usage: "\n -l Assume RTC is kept in local time"
//usage: "\n (if neither is given, read from "ADJTIME_PATH")"
//TODO: get rid of incompatible -t and -l aliases to --systz and --localtime
//TODO: get rid of incompatible -t alias to --systz?
#define HWCLOCK_OPT_LOCALTIME 0x01
#define HWCLOCK_OPT_UTC 0x02
@ -362,7 +391,7 @@ int hwclock_main(int argc UNUSED_PARAM, char **argv)
int utc;
#if ENABLE_LONG_OPTS
static const char hwclock_longopts[] ALIGN1 =
"localtime\0" No_argument "l" /* short opt is non-standard */
"localtime\0" No_argument "l"
"utc\0" No_argument "u"
"show\0" No_argument "r"
"hctosys\0" No_argument "s"
@ -372,12 +401,14 @@ int hwclock_main(int argc UNUSED_PARAM, char **argv)
;
#endif
opt = getopt32long(argv,
"^lurswtf:" "\0" "r--wst:w--rst:s--wrt:t--rsw:l--u:u--l",
"^""lurswtf:v" /* -v is accepted and ignored */
"\0"
"r--wst:w--rst:s--wrt:t--rsw:l--u:u--l",
hwclock_longopts,
&rtcname
);
/* If -u or -l wasn't given check if we are using utc */
/* If -u or -l wasn't given, check if we are using utc */
if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME))
utc = (opt & HWCLOCK_OPT_UTC);
else