blob: c31f84817e6ffd593fd3ed103d04cb8c31d34f75
1 | /* |
2 | * Common RTC functions |
3 | * |
4 | * Licensed under GPLv2, see file LICENSE in this source tree. |
5 | */ |
6 | |
7 | #include "libbb.h" |
8 | #include "rtc_.h" |
9 | |
10 | #if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS |
11 | # define ADJTIME_PATH "/var/lib/hwclock/adjtime" |
12 | #else |
13 | # define ADJTIME_PATH "/etc/adjtime" |
14 | #endif |
15 | |
16 | int FAST_FUNC rtc_adjtime_is_utc(void) |
17 | { |
18 | int utc = 0; |
19 | FILE *f = fopen_for_read(ADJTIME_PATH); |
20 | |
21 | if (f) { |
22 | char buffer[128]; |
23 | |
24 | while (fgets(buffer, sizeof(buffer), f)) { |
25 | if (strncmp(buffer, "UTC", 3) == 0) { |
26 | utc = 1; |
27 | break; |
28 | } |
29 | } |
30 | fclose(f); |
31 | } |
32 | |
33 | return utc; |
34 | } |
35 | |
36 | int FAST_FUNC rtc_xopen(const char **default_rtc, int flags) |
37 | { |
38 | int rtc; |
39 | |
40 | if (!*default_rtc) { |
41 | *default_rtc = "/dev/rtc"; |
42 | rtc = open(*default_rtc, flags); |
43 | if (rtc >= 0) |
44 | return rtc; |
45 | *default_rtc = "/dev/rtc0"; |
46 | rtc = open(*default_rtc, flags); |
47 | if (rtc >= 0) |
48 | return rtc; |
49 | *default_rtc = "/dev/misc/rtc"; |
50 | } |
51 | |
52 | return xopen(*default_rtc, flags); |
53 | } |
54 | |
55 | void FAST_FUNC rtc_read_tm(struct tm *ptm, int fd) |
56 | { |
57 | memset(ptm, 0, sizeof(*ptm)); |
58 | xioctl(fd, RTC_RD_TIME, ptm); |
59 | ptm->tm_isdst = -1; /* "not known" */ |
60 | } |
61 | |
62 | time_t FAST_FUNC rtc_tm2time(struct tm *ptm, int utc) |
63 | { |
64 | char *oldtz = NULL; |
65 | time_t t; |
66 | |
67 | if (utc) { |
68 | oldtz = getenv("TZ"); |
69 | putenv((char*)"TZ=UTC0"); |
70 | tzset(); |
71 | } |
72 | |
73 | t = mktime(ptm); |
74 | |
75 | if (utc) { |
76 | unsetenv("TZ"); |
77 | if (oldtz) |
78 | putenv(oldtz - 3); |
79 | tzset(); |
80 | } |
81 | |
82 | return t; |
83 | } |
84 |