split some rtc funcs out of hwclock and into an rtc header/lib so that the new rtcwake applet as well as hwclock can utilize the same code

2 files changed, 88 insertions, 0 deletions

diff --git a/libbb/Kbuild b/libbb/Kbuild
index c4aac95bb..2fb1b2420 100644
--- a/libbb/Kbuild
+++ b/libbb/Kbuild
@@ -115,6 +115,8 @@ lib-$(CONFIG_LOGIN) += correct_password.o
 lib-$(CONFIG_DF) += find_mount_point.o
 lib-$(CONFIG_MKFS_MINIX) += find_mount_point.o
 lib-$(CONFIG_SELINUX) += selinux_common.o
+lib-$(CONFIG_HWCLOCK) += rtc.o
+lib-$(CONFIG_RTCWAKE) += rtc.o
 
 # We shouldn't build xregcomp.c if we don't need it - this ensures we don't
 # require regex.h to be in the include dir even if we don't need it thereby
diff --git a/libbb/rtc.c b/libbb/rtc.c
new file mode 100644
index 000000000..4cbf32206
--- /dev/null
+++ b/libbb/rtc.c
@@ -0,0 +1,86 @@
+/*
+ * Common RTC functions
+ */
+
+#include "libbb.h"
+#include "rtc_.h"
+
+#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
+# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
+#else
+# define ADJTIME_PATH "/etc/adjtime"
+#endif
+
+int rtc_adjtime_is_utc(void)
+{
+        int utc = 0;
+        FILE *f = fopen(ADJTIME_PATH, "r");
+
+        if (f) {
+                RESERVE_CONFIG_BUFFER(buffer, 128);
+
+                while (fgets(buffer, sizeof(buffer), f)) {
+                        int len = strlen(buffer);
+
+                        while (len && isspace(buffer[len - 1]))
+                                len--;
+
+                        buffer[len] = 0;
+
+                        if (strncmp(buffer, "UTC", 3) == 0) {
+                                utc = 1;
+                                break;
+                        }
+                }
+                fclose(f);
+
+                RELEASE_CONFIG_BUFFER(buffer);
+        }
+
+        return utc;
+}
+
+int rtc_xopen(const char *default_rtc, int flags)
+{
+        int rtc;
+
+        if (!default_rtc) {
+                rtc = open("/dev/rtc", flags);
+                if (rtc >= 0)
+                        return rtc;
+                rtc = open("/dev/rtc0", flags);
+                if (rtc >= 0)
+                        return rtc;
+                default_rtc = "/dev/misc/rtc";
+        }
+
+        return xopen(default_rtc, flags);
+}
+
+time_t rtc_read_time(int fd, int utc)
+{
+        struct tm tm;
+        char *oldtz = 0;
+        time_t t = 0;
+
+        memset(&tm, 0, sizeof(struct tm));
+        xioctl(fd, RTC_RD_TIME, &tm);
+        tm.tm_isdst = -1; /* not known */
+
+        if (utc) {
+                oldtz = getenv("TZ");
+                putenv((char*)"TZ=UTC0");
+                tzset();
+        }
+
+        t = mktime(&tm);
+
+        if (utc) {
+                unsetenv("TZ");
+                if (oldtz)
+                        putenv(oldtz - 3);
+                tzset();
+        }
+
+        return t;
+}