clock-util: be more tolerant in parsing /etc/adjtime

martinpitt · martinpitt · commit 35f7216f9680 · 2016-02-26T12:33:41.000+01:00
As we default to "hardware clock is in UTC" if /etc/adjtime is not present, it also makes sense to have that default if /etc/adjtime contains only one or two lines. Drop the "gibberish" test case, as this was just EIO because of not containing three lines, which is already contained in other tests. clock_is_localtime() never actually validated the format of the first two lines, and there is little point in doing that. This addresses the reading half of issue systemd#2638.
diff --git a/src/basic/clock-util.c b/src/basic/clock-util.c
@@ -91,14 +91,16 @@ int clock_is_localtime(const char* adjtime_path) {
                         fgets(line, sizeof(line), f) &&
                         fgets(line, sizeof(line), f);
                 if (!b)
-                        return -EIO;
+                        /* less than three lines -> default to UTC */
+                        return 0;
 
                 truncate_nl(line);
                 return streq(line, "LOCAL");
 
         } else if (errno != ENOENT)
                 return -errno;
 
+        /* adjtime not present -> default to UTC */
         return 0;
 }
 
diff --git a/src/test/test-clock.c b/src/test/test-clock.c
@@ -41,10 +41,14 @@ static void test_clock_is_localtime(void) {
                 /* no final EOL */
                 {"0.0 0 0\n0\nUTC", 0},
                 {"0.0 0 0\n0\nLOCAL", 1},
+                /* empty value -> defaults to UTC */
+                {"0.0 0 0\n0\n", 0},
                 /* unknown value -> defaults to UTC */
                 {"0.0 0 0\n0\nFOO\n", 0},
-                /* gibberish */
-                {"br0ken", -EIO},
+                /* no third line */
+                {"0.0 0 0", 0},
+                {"0.0 0 0\n", 0},
+                {"0.0 0 0\n0", 0},
         };
 
         /* without an adjtime file we default to UTC */
@@ -75,11 +79,9 @@ static void test_clock_is_localtime_system(void) {
 
         if (access("/etc/adjtime", F_OK) == 0) {
                 log_info("/etc/adjtime exists, clock_is_localtime() == %i", r);
-                /* we cannot assert much if /etc/adjtime exists, just that we
-                 * expect either an answer, or an EIO if the local file really
-                 * is badly malformed. I. e. we don't expect any other error
-                 * code or crash. */
-                assert(r == 0 || r == 1 || r == -EIO);
+                /* if /etc/adjtime exists we expect some answer, no error or
+                 * crash */
+                assert(r == 0 || r == 1);
         } else
                 /* default is UTC if there is no /etc/adjtime */
                 assert(r == 0);
