hwclock: fix musl breakage of settimeofday(tz)
function old new delta
set_kernel_timezone_and_clock - 119 +119
set_kernel_tz - 28 +28
hwclock_main 480 301 -179
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 0/1 up/down: 147/-179) Total: -32 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/hwclock.c b/util-linux/hwclock.c
index 791525f..44cb479 100644
--- a/util-linux/hwclock.c
+++ b/util-linux/hwclock.c
@@ -36,6 +36,19 @@
#include <sys/utsname.h>
#include "rtc_.h"
+
+//musl has no __MUSL__ or similar define to check for,
+//but its <sys/types.h> has these lines:
+// #define __NEED_fsblkcnt_t
+// #define __NEED_fsfilcnt_t
+#if defined(__linux__) && defined(__NEED_fsblkcnt_t) && defined(__NEED_fsfilcnt_t)
+# define LIBC_IS_MUSL 1
+# include <sys/syscall.h>
+#else
+# define LIBC_IS_MUSL 0
+#endif
+
+
/* diff code is disabled: it's not sys/hw clock diff, it's some useless
* "time between hwclock was started and we saw CMOS tick" quantity.
* It's useless since hwclock is started at a random moment,
@@ -116,26 +129,73 @@
#endif
}
+static void set_kernel_tz(const struct timezone *tz)
+{
+#if LIBC_IS_MUSL
+ /* musl libc does not pass tz argument to syscall
+ * because "it's deprecated by POSIX, therefore it's fine
+ * if we gratuitously break stuff" :(
+ */
+#if !defined(SYS_settimeofday) && defined(SYS_settimeofday_time32)
+# define SYS_settimeofday SYS_settimeofday_time32
+#endif
+ int ret = syscall(SYS_settimeofday, NULL, tz);
+#else
+ int ret = settimeofday(NULL, tz);
+#endif
+ if (ret)
+ bb_simple_perror_msg_and_die("settimeofday");
+}
+
+/*
+ * At system boot, kernel may set system time from RTC,
+ * but it knows nothing about timezones. If RTC is in local time,
+ * 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.
+ *
+ * util-linux's code has this comment:
+ * RTC | settimeofday calls
+ * ------|-------------------------------------------------
+ * Local | 1) 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,
+ * it makes kernel save RTC in local time, not UTC.)
+ */
+static void set_kernel_timezone_and_clock(int utc, const struct timeval *hctosys)
+{
+ time_t cur;
+ struct tm *broken;
+ struct timezone tz = { 0 };
+
+ /* if --utc, prevent kernel's warp_clock() with a dummy call */
+ if (utc)
+ set_kernel_tz(&tz);
+
+ /* Set kernel's timezone offset based on userspace one */
+ cur = time(NULL);
+ broken = localtime(&cur);
+ tz.tz_minuteswest = -broken->tm_gmtoff / 60;
+ /*tz.tz_dsttime = 0; already is */
+ set_kernel_tz(&tz); /* MIGHT warp_clock() if 1st call since boot */
+
+ if (hctosys) { /* it's --hctosys: set time too */
+ if (settimeofday(hctosys, NULL))
+ bb_simple_perror_msg_and_die("settimeofday");
+ }
+}
+
static void to_sys_clock(const char **pp_rtcname, int utc)
{
struct timeval tv;
- struct timezone tz;
-
- tz.tz_minuteswest = timezone / 60;
- /* ^^^ used to also subtract 60*daylight, but it's wrong:
- * daylight!=0 means "this timezone has some DST
- * during the year", not "DST is in effect now".
- */
- tz.tz_dsttime = 0;
-
- /* glibc v2.31+ returns an error if both args are non-NULL */
- if (settimeofday(NULL, &tz))
- bb_simple_perror_msg_and_die("settimeofday");
tv.tv_sec = read_rtc(pp_rtcname, NULL, utc);
tv.tv_usec = 0;
- if (settimeofday(&tv, NULL))
- bb_simple_perror_msg_and_die("settimeofday");
+ return set_kernel_timezone_and_clock(utc, &tv);
}
static void from_sys_clock(const char **pp_rtcname, int utc)
@@ -261,39 +321,6 @@
close(rtc);
}
-/*
- * At system boot, kernel may set system time from RTC,
- * but it knows nothing about timezones. If RTC is in local time,
- * then system time is wrong - it is offset by timezone.
- * This 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.
- */
-static void set_system_clock_timezone(int utc)
-{
- struct timeval tv;
- struct tm *broken;
- struct timezone tz;
-
- gettimeofday(&tv, NULL);
- broken = localtime(&tv.tv_sec);
- tz.tz_minuteswest = timezone / 60;
- if (broken->tm_isdst > 0)
- tz.tz_minuteswest -= 60;
- tz.tz_dsttime = 0;
- gettimeofday(&tv, NULL);
- if (!utc)
- tv.tv_sec += tz.tz_minuteswest * 60;
-
- /* glibc v2.31+ returns an error if both args are non-NULL */
- if (settimeofday(NULL, &tz))
- bb_simple_perror_msg_and_die("settimeofday");
- if (settimeofday(&tv, NULL))
- bb_simple_perror_msg_and_die("settimeofday");
-}
-
//usage:#define hwclock_trivial_usage
//usage: IF_LONG_OPTS(
//usage: "[-swu] [--systz] [--localtime] [-f FILE]"
@@ -333,7 +360,6 @@
const char *rtcname = NULL;
unsigned opt;
int utc;
-
#if ENABLE_LONG_OPTS
static const char hwclock_longopts[] ALIGN1 =
"localtime\0" No_argument "l" /* short opt is non-standard */
@@ -345,10 +371,6 @@
"rtc\0" Required_argument "f"
;
#endif
-
- /* Initialize "timezone" (libc global variable) */
- tzset();
-
opt = getopt32long(argv,
"^lurswtf:" "\0" "r--wst:w--rst:s--wrt:t--rsw:l--u:u--l",
hwclock_longopts,
@@ -366,7 +388,7 @@
else if (opt & HWCLOCK_OPT_SYSTOHC)
from_sys_clock(&rtcname, utc);
else if (opt & HWCLOCK_OPT_SYSTZ)
- set_system_clock_timezone(utc);
+ set_kernel_timezone_and_clock(utc, NULL);
else
/* default HWCLOCK_OPT_SHOW */
show_clock(&rtcname, utc);