dynamic_debug: tighten up error checking on debug queries

Issue error when a match-spec is given multiple times in a rule. Previous code kept last one, but was silent about it. Docs imply only one is allowed by saying match-specs are ANDed together, given that module M cannot match both A and B. Also error when last_line < 1st_line. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

dynamic_debug: tighten up error checking on debug queries
Issue error when a match-spec is given multiple times in a rule. Previous code kept last one, but was silent about it. Docs imply only one is allowed by saying match-specs are ANDed together, given that module M cannot match both A and B. Also error when last_line < 1st_line. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jim Cromie · Greg Kroah-Hartman
1 parent 5ca7d2a6c5
Showing 1 changed file with 33 additions and 6 deletions Side-by-side Diff
lib/dynamic_debug.c
@@ -276,6 +276,19 @@
 	return str;
 }
  
+static int check_set(const char **dest, char *src, char *name)
+{
+	int rc = 0;
+
+	if (*dest) {
+		rc = -EINVAL;
+		pr_err("match-spec:%s val:%s overridden by %s",
+			name, *dest, src);
+	}
+	*dest = src;
+	return rc;
+}
+
 /*
  * Parse words[] as a ddebug query specification, which is a series
  * of (keyword, value) pairs chosen from these possibilities:
  
@@ -287,11 +300,15 @@
  * format <escaped-string-to-find-in-format>
  * line <lineno>
  * line <first-lineno>-<last-lineno> // where either may be empty
+ *
+ * Only 1 of each type is allowed.
+ * Returns 0 on success, <0 on error.
  */
 static int ddebug_parse_query(char *words[], int nwords,
 			       struct ddebug_query *query)
 {
 	unsigned int i;
+	int rc;
  
 	/* check we have an even number of words */
 	if (nwords % 2 != 0)
  
  
  
  
  
  
  
@@ -300,24 +317,32 @@
  
 	for (i = 0 ; i < nwords ; i += 2) {
 		if (!strcmp(words[i], "func"))
-			query->function = words[i+1];
+			rc = check_set(&query->function, words[i+1], "func");
 		else if (!strcmp(words[i], "file"))
-			query->filename = words[i+1];
+			rc = check_set(&query->filename, words[i+1], "file");
 		else if (!strcmp(words[i], "module"))
-			query->module = words[i+1];
+			rc = check_set(&query->module, words[i+1], "module");
 		else if (!strcmp(words[i], "format"))
-			query->format = unescape(words[i+1]);
+			rc = check_set(&query->format, unescape(words[i+1]),
+				"format");
 		else if (!strcmp(words[i], "line")) {
 			char *first = words[i+1];
 			char *last = strchr(first, '-');
+			if (query->first_lineno || query->last_lineno) {
+				pr_err("match-spec:line given 2 times\n");
+				return -EINVAL;
+			}
 			if (last)
 				*last++ = '\0';
 			if (parse_lineno(first, &query->first_lineno) < 0)
 				return -EINVAL;
-			if (last != NULL) {
+			if (last) {
 				/* range <first>-<last> */
-				if (parse_lineno(last, &query->last_lineno) < 0)
+				if (parse_lineno(last, &query->last_lineno)
+				    < query->first_lineno) {
+					pr_err("last-line < 1st-line\n");
 					return -EINVAL;
+				}
 			} else {
 				query->last_lineno = query->first_lineno;
 			}
@@ -325,6 +350,8 @@
 			pr_err("unknown keyword \"%s\"\n", words[i]);
 			return -EINVAL;
 		}
+		if (rc)
+			return rc;
 	}
  
 	if (verbose)
...	...	@@ -276,6 +276,19 @@
276	276	return str;
277	277	}
278	278
	279	+static int check_set(const char *dest, char src, char *name)
	280	+{
	281	+ int rc = 0;
	282	+
	283	+ if (*dest) {
	284	+ rc = -EINVAL;
	285	+ pr_err("match-spec:%s val:%s overridden by %s",
	286	+ name, *dest, src);
	287	+ }
	288	+ *dest = src;
	289	+ return rc;
	290	+}
	291	+
279	292	/*
280	293	* Parse words[] as a ddebug query specification, which is a series
281	294	* of (keyword, value) pairs chosen from these possibilities:
282	295
...	...	@@ -287,11 +300,15 @@
287	300	* format <escaped-string-to-find-in-format>
288	301	* line <lineno>
289	302	* line <first-lineno>-<last-lineno> // where either may be empty
	303	+ *
	304	+ * Only 1 of each type is allowed.
	305	+ * Returns 0 on success, <0 on error.
290	306	*/
291	307	static int ddebug_parse_query(char *words[], int nwords,
292	308	struct ddebug_query *query)
293	309	{
294	310	unsigned int i;
	311	+ int rc;
295	312
296	313	/* check we have an even number of words */
297	314	if (nwords % 2 != 0)
298	315
299	316
300	317
301	318
302	319
303	320
304	321
...	...	@@ -300,24 +317,32 @@
300	317
301	318	for (i = 0 ; i < nwords ; i += 2) {
302	319	if (!strcmp(words[i], "func"))
303		- query->function = words[i+1];
	320	+ rc = check_set(&query->function, words[i+1], "func");
304	321	else if (!strcmp(words[i], "file"))
305		- query->filename = words[i+1];
	322	+ rc = check_set(&query->filename, words[i+1], "file");
306	323	else if (!strcmp(words[i], "module"))
307		- query->module = words[i+1];
	324	+ rc = check_set(&query->module, words[i+1], "module");
308	325	else if (!strcmp(words[i], "format"))
309		- query->format = unescape(words[i+1]);
	326	+ rc = check_set(&query->format, unescape(words[i+1]),
	327	+ "format");
310	328	else if (!strcmp(words[i], "line")) {
311	329	char *first = words[i+1];
312	330	char *last = strchr(first, '-');
	331	+ if (query->first_lineno \|\| query->last_lineno) {
	332	+ pr_err("match-spec:line given 2 times\n");
	333	+ return -EINVAL;
	334	+ }
313	335	if (last)
314	336	*last++ = '\0';
315	337	if (parse_lineno(first, &query->first_lineno) < 0)
316	338	return -EINVAL;
317		- if (last != NULL) {
	339	+ if (last) {
318	340	/* range <first>-<last> */
319		- if (parse_lineno(last, &query->last_lineno) < 0)
	341	+ if (parse_lineno(last, &query->last_lineno)
	342	+ < query->first_lineno) {
	343	+ pr_err("last-line < 1st-line\n");
320	344	return -EINVAL;
	345	+ }
321	346	} else {
322	347	query->last_lineno = query->first_lineno;
323	348	}
...	...	@@ -325,6 +350,8 @@
325	350	pr_err("unknown keyword \"%s\"\n", words[i]);
326	351	return -EINVAL;
327	352	}
	353	+ if (rc)
	354	+ return rc;
328	355	}
329	356
330	357	if (verbose)