Make timestamp generation never fail.

If, for whatever reason, quering current time fails
then the whole log message is dropped.

This PR assures the log message is not lost and
the output is done with the default timestamp.

Signed-off-by: Jindrich Novy <[email protected]>

src/ctr_logging.c

@@ -87,7 +87,7 @@ static bool get_line_len(ptrdiff_t *line_len, const char *buf, ssize_t buflen);
 static ssize_t writev_buffer_append_segment(int fd, writev_buffer_t *buf, const void *data, ssize_t len);
 static ssize_t writev_buffer_append_segment_no_flush(writev_buffer_t *buf, const void *data, ssize_t len);
 static ssize_t writev_buffer_flush(int fd, writev_buffer_t *buf);
-static int set_k8s_timestamp(char *buf, ssize_t buflen, const char *pipename);
+static void set_k8s_timestamp(char *buf, ssize_t buflen, const char *pipename);
 static void reopen_k8s_file(void);
 
 
@@ -356,9 +356,7 @@ static int write_k8s_log(stdpipe_t pipe, const char *buf, ssize_t buflen)
 	 * fast.
 	 */
 	char tsbuf[TSBUFLEN];
-	if (set_k8s_timestamp(tsbuf, sizeof tsbuf, stdpipe_name(pipe)))
-		/* TODO: We should handle failures much more cleanly than this. */
-		return -1;
+	set_k8s_timestamp(tsbuf, sizeof tsbuf, stdpipe_name(pipe));
 
 	ptrdiff_t line_len = 0;
 	while (buflen > 0) {
@@ -542,46 +540,57 @@ static const char *stdpipe_name(stdpipe_t pipe)
 	}
 }
 
-
-static int set_k8s_timestamp(char *buf, ssize_t buflen, const char *pipename)
+/* Generate timestamp string to buf. */
+static void set_k8s_timestamp(char *buf, ssize_t buflen, const char *pipename)
 {
 	static int tzset_called = 0;
-	int err = -1;
 
-	struct timespec ts;
+	/* Initialize timestamp variables with sensible defaults. */
+	struct timespec ts = {0};
+	struct tm current_tm = {0};
+	char off_sign = '+';
+	int off = 0;
+
+	/* Attempt to get the current time. */
 	if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
-		/* If CLOCK_REALTIME is not supported, we set nano seconds to 0 */
-		if (errno == EINVAL) {
-			ts.tv_nsec = 0;
-		} else {
-			return err;
+		if (errno != EINVAL) {
+			ts.tv_nsec = 0; /* If other errors, fallback to nanoseconds = 0. */
 		}
 	}
 
+	/* Ensure tzset is called only once. */
 	if (!tzset_called) {
 		tzset();
 		tzset_called = 1;
 	}
 
-	struct tm current_tm;
-	if (localtime_r(&ts.tv_sec, &current_tm) == NULL)
-		return err;
-
+	/* Get the local time or fallback to defaults. */
+	if (localtime_r(&ts.tv_sec, &current_tm) == NULL) {
+		current_tm.tm_year = 70; /* 1970 (default epoch year) */
+		current_tm.tm_mon = 0;	 /* January */
+		current_tm.tm_mday = 1;	 /* 1st day of the month */
+		current_tm.tm_hour = 0;	 /* midnight */
+		current_tm.tm_min = 0;
+		current_tm.tm_sec = 0;
+		current_tm.tm_gmtoff = 0; /* UTC offset */
+	}
 
-	char off_sign = '+';
-	int off = (int)current_tm.tm_gmtoff;
-	if (current_tm.tm_gmtoff < 0) {
+	/* Calculate timezone offset. */
+	off = (int)current_tm.tm_gmtoff;
+	if (off < 0) {
 		off_sign = '-';
 		off = -off;
 	}
 
+	/* Format the timestamp into the buffer. */
 	int len = snprintf(buf, buflen, "%d-%02d-%02dT%02d:%02d:%02d.%09ld%c%02d:%02d %s ", current_tm.tm_year + 1900,
 			   current_tm.tm_mon + 1, current_tm.tm_mday, current_tm.tm_hour, current_tm.tm_min, current_tm.tm_sec, ts.tv_nsec,
 			   off_sign, off / 3600, (off % 3600) / 60, pipename);
 
-	if (len < buflen)
-		err = 0;
-	return err;
+	/* Ensure null termination if snprintf output exceeds buffer length. */
+	if (len >= buflen && buflen > 0) {
+		buf[buflen - 1] = '\0';
+	}
 }
 
 /* Force closing any open FD. */