busybox/libbb/rtc.c

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/*
* Common RTC functions
2008-12-07 06:22:58 +05:30
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "rtc_.h"
int FAST_FUNC rtc_adjtime_is_utc(void)
{
int utc = 0;
FILE *f = fopen_for_read(ADJTIME_PATH);
if (f) {
char buffer[128];
while (fgets(buffer, sizeof(buffer), f)) {
libbb: introduce and use is_prefixed_with() function old new delta is_prefixed_with - 18 +18 complete_username 78 77 -1 man_main 737 735 -2 fsck_device 429 427 -2 unpack_ar_archive 80 76 -4 strip_unsafe_prefix 105 101 -4 singlemount 1054 1050 -4 rtc_adjtime_is_utc 90 86 -4 resolve_mount_spec 88 84 -4 parse_one_line 1029 1025 -4 parse_conf 1460 1456 -4 may_wakeup 83 79 -4 loadkmap_main 219 215 -4 get_irqs_from_stat 103 99 -4 get_header_cpio 913 909 -4 findfs_main 79 75 -4 fbsplash_main 1230 1226 -4 load_crontab 776 771 -5 expand_vars_to_list 1151 1146 -5 date_main 881 876 -5 skip_dev_pfx 30 24 -6 make_device 2199 2193 -6 complete_cmd_dir_file 773 767 -6 run_applet_and_exit 715 708 -7 uudecode_main 321 313 -8 pwdx_main 197 189 -8 execute 568 560 -8 i2cdetect_main 1186 1176 -10 procps_scan 1242 1230 -12 procps_read_smaps 1017 1005 -12 process_module 746 734 -12 patch_main 1903 1891 -12 nfsmount 3572 3560 -12 stack_machine 126 112 -14 process_timer_stats 449 435 -14 match_fstype 111 97 -14 do_ipaddr 1344 1330 -14 open_list_and_close 359 343 -16 get_header_tar 1795 1779 -16 prepend_new_eth_table 340 323 -17 fsck_main 1811 1794 -17 find_iface_state 56 38 -18 dnsd_main 1321 1303 -18 base_device 179 158 -21 find_keyword 104 82 -22 handle_incoming_and_exit 2785 2762 -23 parse_and_put_prompt 774 746 -28 modinfo 347 317 -30 find_action 204 171 -33 update_passwd 1470 1436 -34 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/49 up/down: 18/-540) Total: -522 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2015-03-12 22:18:34 +05:30
if (is_prefixed_with(buffer, "UTC")) {
utc = 1;
break;
}
}
fclose(f);
}
return utc;
}
/* rtc opens are exclusive.
* Try to run two "hwclock -w" at the same time to see it.
* Users wouldn't expect that to fail merely because /dev/rtc
* was momentarily busy, let's try a bit harder on errno == EBUSY.
*/
static int open_loop_on_busy(const char *name, int flags)
{
int rtc;
/*
* Tested with two parallel "hwclock -w" loops.
* With try = 10, no failures with 2x1000000 loop iterations.
*/
int try = 1000 / 20;
again:
errno = 0;
rtc = open(name, flags);
if (errno == EBUSY) {
usleep(20 * 1000);
if (--try != 0)
goto again;
/* EBUSY. Last try, exit on error instead of returning -1 */
return xopen(name, flags);
}
return rtc;
}
/* Never fails */
int FAST_FUNC rtc_xopen(const char **default_rtc, int flags)
{
int rtc;
const char *name =
"/dev/rtc""\0"
"/dev/rtc0""\0"
"/dev/misc/rtc""\0";
if (!*default_rtc)
goto try_name;
name = ""; /*else: we have rtc name, don't try other names */
for (;;) {
rtc = open_loop_on_busy(*default_rtc, flags);
if (rtc >= 0)
return rtc;
if (!name[0])
return xopen(*default_rtc, flags);
try_name:
*default_rtc = name;
name += strlen(name) + 1;
}
}
void FAST_FUNC rtc_read_tm(struct tm *ptm, int fd)
{
memset(ptm, 0, sizeof(*ptm));
xioctl(fd, RTC_RD_TIME, ptm);
ptm->tm_isdst = -1; /* "not known" */
}
time_t FAST_FUNC rtc_tm2time(struct tm *ptm, int utc)
{
char *oldtz = oldtz; /* for compiler */
time_t t;
if (utc) {
oldtz = getenv("TZ");
putenv((char*)"TZ=UTC0");
tzset();
}
t = mktime(ptm);
if (utc) {
unsetenv("TZ");
if (oldtz)
putenv(oldtz - 3);
tzset();
}
return t;
}