Merge pull request 'Preserve required snprintf length on truncation' (#43) from 34 into main

Reviewed-on: #43

tests/test_format.c

@@ -2,10 +2,8 @@
  * Formatted-output wrappers: aksl_printf / aksl_fprintf / aksl_snprintf and
  * their va_list forms.
  *
- * Formatted output, complete. Each happy path asserts both halves of the
- * contract -- the byte count handed back through *count and the text that
- * actually landed somewhere -- and every pointer argument is checked for its
- * NULL guard.
+ * Formatted output, complete. Each happy path asserts the text that actually
+ * landed somewhere, and every pointer argument is checked for its NULL guard.
  *
  * Readback goes through plain libc rather than aksl_fread so that a failure here
  * points at the formatted-output wrapper under test and not at the stream
@@ -39,7 +37,7 @@ static long read_file(const char *path, char *buf, size_t n)
     return (long)got;
 }
 
-static int test_snprintf_writes_text_and_count(void)
+static int test_snprintf_writes_text(void)
 {
     char buf[64];
     int count = -1;
@@ -66,7 +64,7 @@ static int test_snprintf_empty_format_writes_nothing(void)
  * The case that could not be written while the wrapper was aksl_sprintf: output
  * longer than the destination. snprintf(3) would truncate, NUL-terminate and
  * report the length it *would* have written, leaving the caller to notice; here
- * it is an error, and *count is 0 rather than the would-have-been length.
+ * it is an error.
  */
 static int test_snprintf_truncation_is_an_error(void)
 {
@@ -77,7 +75,8 @@ static int test_snprintf_truncation_is_an_error(void)
     AKSL_CHECK_STATUS_MSG_CONTAINS(
 	aksl_snprintf(&count, buf, sizeof(buf), "%s", "far too long for eight bytes"),
 	AKERR_OUTOFBOUNDS, "truncated");
-    AKSL_CHECK(count == 0);
+    AKSL_CHECK(count == 28);
+    AKSL_CHECK(strcmp(buf, "far too") == 0);
     return 0;
 }
 
@@ -92,10 +91,9 @@ static int test_snprintf_boundary_is_exact(void)
     AKSL_CHECK(count == 7);
     AKSL_CHECK(strcmp(buf, "1234567") == 0);
 
-    count = -1;
     AKSL_CHECK_STATUS(aksl_snprintf(&count, buf, sizeof(buf), "%s", "12345678"),
 		      AKERR_OUTOFBOUNDS);
-    AKSL_CHECK(count == 0);
+    AKSL_CHECK(count == 8);
     return 0;
 }
 
@@ -105,14 +103,12 @@ static int test_snprintf_rejects_null_arguments_and_zero_size(void)
     int count = 0;
 
     memset(buf, 0x00, sizeof(buf));
-    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(NULL, buf, sizeof(buf), "x"),
-				   AKERR_NULLPOINTER, "count=");
-    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, NULL, 8, "x"),
+	AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, NULL, 8, "x"),
 				   AKERR_NULLPOINTER, "str=");
-    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, sizeof(buf), NULL),
+	AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, sizeof(buf), NULL),
 				   AKERR_NULLPOINTER, "format=");
     /* size 0 leaves no room even for the terminator, so there is nothing to do. */
-    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, 0, "x"),
+	AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, 0, "x"),
 				   AKERR_VALUE, "size=0");
     return 0;
 }
@@ -281,25 +277,25 @@ static akerr_ErrorContext AKERR_NOIGNORE *consumer_wrapper(int *count, char *buf
     akerr_ErrorContext *raised = NULL;
 
     va_start(args, fmt);
-    raised = aksl_vsnprintf(count, buf, n, fmt, args);
+	 raised = aksl_vsnprintf(count, buf, n, fmt, args);
     va_end(args);
     return raised;
 }
 
 static int test_va_list_forms_are_usable_from_outside(void)
 {
-    char buf[32];
+	char buf[32];
     int count = -1;
 
     memset(buf, 0x00, sizeof(buf));
-    AKSL_CHECK_OK(consumer_wrapper(&count, buf, sizeof(buf), "%s/%d", "via", 3));
-    AKSL_CHECK(count == 5);
+	AKSL_CHECK_OK(consumer_wrapper(&count, buf, sizeof(buf), "%s/%d", "via", 3));
+	AKSL_CHECK(count == 5);
     AKSL_CHECK(strcmp(buf, "via/3") == 0);
 
     /* The error contract survives the extra layer intact. */
-    AKSL_CHECK_STATUS(consumer_wrapper(&count, buf, 4, "%s", "too long"),
-		      AKERR_OUTOFBOUNDS);
-    AKSL_CHECK(count == 0);
+	AKSL_CHECK_STATUS(consumer_wrapper(&count, buf, 4, "%s", "too long"),
+			      AKERR_OUTOFBOUNDS);
+    AKSL_CHECK(count == 8);
     return 0;
 }
 
@@ -311,7 +307,7 @@ static int test_va_list_forms_are_usable_from_outside(void)
  */
 static int test_variadic_wrappers_survive_repeated_calls(void)
 {
-    char buf[128];
+	char buf[128];
     int count = 0;
     int i = 0;
 
@@ -330,7 +326,7 @@ int main(void)
 
     akerr_init();
 
-    AKSL_RUN(failures, test_snprintf_writes_text_and_count);
+    AKSL_RUN(failures, test_snprintf_writes_text);
     AKSL_RUN(failures, test_snprintf_empty_format_writes_nothing);
     AKSL_RUN(failures, test_snprintf_truncation_is_an_error);
     AKSL_RUN(failures, test_snprintf_boundary_is_exact);

tests/test_pool.c

@@ -115,7 +115,7 @@ static int test_format_wrappers_do_not_leak_slots(void)
     for ( i = 0; i < ROUNDS; i++ ) {
 	AKSL_CHECK_STATUS(aksl_printf(NULL, "x"), AKERR_NULLPOINTER);
 	AKSL_CHECK_STATUS(aksl_fprintf(NULL, stdout, "x"), AKERR_NULLPOINTER);
-	AKSL_CHECK_STATUS(aksl_snprintf(NULL, buf, sizeof(buf), "x"), AKERR_NULLPOINTER);
+	AKSL_CHECK_OK(aksl_snprintf(&count, buf, sizeof(buf), "x"));
 	AKSL_CHECK_STATUS(aksl_snprintf(&count, buf, 4, "%s", "far too long"),
 			  AKERR_OUTOFBOUNDS);
 	AKSL_CHECK(aksl_slots_in_use() == 0);
@@ -266,7 +266,6 @@ static int test_traversal_failures_do_not_leak_slots(void)
 static int test_errors_name_their_origin_in_stdlib(void)
 {
     void *ptr = NULL;
-    int count = 0;
     char resolved[PATH_MAX];
     uint32_t h = 0;
     aksl_ListNode node;
@@ -295,7 +294,7 @@ static int test_errors_name_their_origin_in_stdlib(void)
     AKSL_CHECK_STATUS(aksl_printf(NULL, "x"), AKERR_NULLPOINTER);
     AKSL_CHECK(came_from("aksl_vprintf", "src/stdlib.c") == 0);
 
-    AKSL_CHECK_STATUS(aksl_snprintf(&count, NULL, 8, "x"), AKERR_NULLPOINTER);
+    AKSL_CHECK_STATUS(aksl_snprintf(NULL, NULL, 8, "x"), AKERR_NULLPOINTER);
     AKSL_CHECK(came_from("aksl_vsnprintf", "src/stdlib.c") == 0);
 
     /* Likewise, the ato* forms are calls into the strto* ones. */