d3c36882d
Denys Vlasenko
2020-12-16
Subject
hwclock: improve --help (-l is a compatible shortcut for --localtime)
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util-linux/hwclock.c+50 -19
| @@ -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 | |