kunit: fix bug of extra newline characters in debugfs logs

Fix bug of the extra newline characters in debugfs logs. When a
line is added to debugfs with a newline character at the end,
an extra line appears in the debugfs log.

This is due to a discrepancy between how the lines are printed and how they
are added to the logs. Remove this discrepancy by checking if a newline
character is present before adding a newline character. This should closely
match the printk behavior.

Add kunit_log_newline_test to provide test coverage for this issue.  (Also,
move kunit_log_test above suite definition to remove the unnecessary
declaration prior to the suite definition)

As an example, say we add these two lines to the log:

kunit_log(..., "KTAP version 1\n");
kunit_log(..., "1..1");

The debugfs log before this fix:

 KTAP version 1

 1..1

The debugfs log after this fix:

 KTAP version 1
 1..1

Signed-off-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 0668d29..9721584 100644 (file)
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -420,7 +420,7 @@ void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...);
 #define kunit_log(lvl, test_or_suite, fmt, ...)                                \
        do {                                                            \
                printk(lvl fmt, ##__VA_ARGS__);                         \
-               kunit_log_append((test_or_suite)->log,  fmt "\n",       \
+               kunit_log_append((test_or_suite)->log,  fmt,            \
                                 ##__VA_ARGS__);                        \
        } while (0)
 

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
index 4df0335..b63595d 100644 (file)
--- a/lib/kunit/kunit-test.c
+++ b/lib/kunit/kunit-test.c
@@ -443,18 +443,6 @@ static struct kunit_suite kunit_resource_test_suite = {
        .test_cases = kunit_resource_test_cases,
 };
 
-static void kunit_log_test(struct kunit *test);
-
-static struct kunit_case kunit_log_test_cases[] = {
-       KUNIT_CASE(kunit_log_test),
-       {}
-};
-
-static struct kunit_suite kunit_log_test_suite = {
-       .name = "kunit-log-test",
-       .test_cases = kunit_log_test_cases,
-};
-
 static void kunit_log_test(struct kunit *test)
 {
        struct kunit_suite suite;
@@ -481,6 +469,29 @@ static void kunit_log_test(struct kunit *test)
 #endif
 }
 
+static void kunit_log_newline_test(struct kunit *test)
+{
+       kunit_info(test, "Add newline\n");
+       if (test->log) {
+               KUNIT_ASSERT_NOT_NULL_MSG(test, strstr(test->log, "Add newline\n"),
+                       "Missing log line, full log:\n%s", test->log);
+               KUNIT_EXPECT_NULL(test, strstr(test->log, "Add newline\n\n"));
+       } else {
+               kunit_skip(test, "only useful when debugfs is enabled");
+       }
+}
+
+static struct kunit_case kunit_log_test_cases[] = {
+       KUNIT_CASE(kunit_log_test),
+       KUNIT_CASE(kunit_log_newline_test),
+       {}
+};
+
+static struct kunit_suite kunit_log_test_suite = {
+       .name = "kunit-log-test",
+       .test_cases = kunit_log_test_cases,
+};
+
 static void kunit_status_set_failure_test(struct kunit *test)
 {
        struct kunit fake;

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 811fcc3..e2910b2 100644 (file)
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -108,6 +108,22 @@ static void kunit_print_test_stats(struct kunit *test,
                  stats.total);
 }
 
+/**
+ * kunit_log_newline() - Add newline to the end of log if one is not
+ * already present.
+ * @log: The log to add the newline to.
+ */
+static void kunit_log_newline(char *log)
+{
+       int log_len, len_left;
+
+       log_len = strlen(log);
+       len_left = KUNIT_LOG_SIZE - log_len - 1;
+
+       if (log_len > 0 && log[log_len - 1] != '\n')
+               strncat(log, "\n", len_left);
+}
+
 /*
  * Append formatted message to log, size of which is limited to
  * KUNIT_LOG_SIZE bytes (including null terminating byte).
@@ -135,6 +151,8 @@ void kunit_log_append(char *log, const char *fmt, ...)
        vsnprintf(log + log_len, min(len, len_left), fmt, args);
        va_end(args);
 
+       /* Add newline to end of log if not already present. */
+       kunit_log_newline(log);
 }
 EXPORT_SYMBOL_GPL(kunit_log_append);