UTIL: convert GeneralizedTime to unix time

New utility function *sss_utc_to_time_t* to convert GeneralizedTime to
unix time.

Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

4 files changed, 58 insertions, 0 deletions

diff --git a/src/util/util.c b/src/util/util.c
index 613c559bb..cfd26a58b 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -18,6 +18,7 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include "config.h"
 #include <ctype.h>
 #include <netdb.h>
 #include <poll.h>
@@ -26,6 +27,7 @@
 #include <arpa/inet.h>
 #include <talloc.h>
 #include <dhash.h>
+#include <time.h>
 
 #include "util/util.h"
 #include "util/sss_utf8.h"
@@ -904,3 +906,54 @@ errno_t sss_fd_nonblocking(int fd)
 
     return EOK;
 }
+
+/* Convert GeneralizedTime (http://en.wikipedia.org/wiki/GeneralizedTime)
+ * to unix time (seconds since epoch). Use UTC time zone.
+ */
+errno_t sss_utc_to_time_t(const char *str, const char *format, time_t *_unix_time)
+{
+    char *end;
+    struct tm tm;
+    size_t len;
+    time_t ut;
+
+    if (str == NULL) {
+        return EINVAL;
+    }
+
+    len = strlen(str);
+    if (str[len-1] != 'Z') {
+        DEBUG(SSSDBG_TRACE_INTERNAL,
+              "%s does not seem to be in UTZ time zone.\n", str);
+        return ERR_TIMESPEC_NOT_SUPPORTED;
+    }
+
+    memset(&tm, 0, sizeof(tm));
+
+    end = strptime(str, format, &tm);
+    /* not all characters from format were matched */
+    if (end == NULL) {
+        DEBUG(SSSDBG_TRACE_INTERNAL,
+              "String [%s] failed to match format [%s].\n", str, format);
+        return EINVAL;
+    }
+
+    /* str is 'longer' than format */
+    if (*end != '\0') {
+        DEBUG(SSSDBG_TRACE_INTERNAL,
+              "String [%s] is longer than format [%s].\n", str, format);
+        return EINVAL;
+    }
+
+    ut = mktime(&tm);
+    if (ut == -1) {
+        DEBUG(SSSDBG_TRACE_INTERNAL,
+              "mktime failed to convert [%s].\n", str);
+        return EINVAL;
+    }
+
+    tzset();
+    ut -= timezone;
+    *_unix_time = ut;
+    return EOK;
+}
diff --git a/src/util/util.h b/src/util/util.h
index 22d6ef0a4..829cf567a 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -648,4 +648,7 @@ int set_seuser(const char *login_name, const char *seuser_name,
                const char *mlsrange);
 int del_seuser(const char *login_name);
 
+/* convert time from generalized form to unix time */
+errno_t sss_utc_to_time_t(const char *str, const char *format, time_t *unix_time);
+
 #endif /* __SSSD_UTIL_H__ */
diff --git a/src/util/util_errors.c b/src/util/util_errors.c
index 16d16fc77..bfae5cd18 100644
--- a/src/util/util_errors.c
+++ b/src/util/util_errors.c
@@ -65,6 +65,7 @@ struct err_string error_to_str[] = {
     { "LDAP search returned a referral" }, /* ERR_REFERRAL */
     { "Error setting SELinux user context" }, /* ERR_SELINUX_CONTEXT */
     { "Username format not allowed by re_expression" }, /* ERR_REGEX_NOMATCH */
+    { "Time specification not supported" }, /* ERR_TIMESPEC_NOT_SUPPORTED */
 };
 
 
diff --git a/src/util/util_errors.h b/src/util/util_errors.h
index 97e210e31..069d4b78a 100644
--- a/src/util/util_errors.h
+++ b/src/util/util_errors.h
@@ -90,6 +90,7 @@ enum sssd_errors {
     ERR_REFERRAL,
     ERR_SELINUX_CONTEXT,
     ERR_REGEX_NOMATCH,
+    ERR_TIMESPEC_NOT_SUPPORTED,
     ERR_LAST            /* ALWAYS LAST */
 };