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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Clark Williams <williams@redhat.com>,
	Karim Yaghmour <karim.yaghmour@opersys.com>,
	Brendan Gregg <bgregg@netflix.com>,
	Joel Fernandes <joelaf@google.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-rt-users@vger.kernel.org
Subject: [RFC][PATCH 07/10] tracing: Have zero size length in filter logic be full string
Date: Fri, 11 May 2018 15:49:34 -0400	[thread overview]
Message-ID: <20180511195341.034688188@goodmis.org> (raw)
In-Reply-To: <20180511194927.190877137@goodmis.org>

[-- Attachment #1: 0007-tracing-Have-zero-size-length-in-filter-logic-be-ful.patch --]
[-- Type: text/plain, Size: 1996 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

As strings in trace events may not have a nul terminating character, the
filter string compares use the defined string length for the field for the
compares.

The trace_marker records data slightly different than do normal events. It's
size is zero, meaning that the string is the rest of the array, and that the
string also ends with '\0'.

If the size is zero, assume that the string is nul terminated and read the
string in question as is.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_filter.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 7d306b74230f..675392b9edd2 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -750,31 +750,32 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
  *
  * Note:
  * - @str might not be NULL-terminated if it's of type DYN_STRING
- *   or STATIC_STRING
+ *   or STATIC_STRING, unless @len is zero.
  */
 
 static int regex_match_full(char *str, struct regex *r, int len)
 {
-	if (strncmp(str, r->pattern, len) == 0)
-		return 1;
-	return 0;
+	/* len means str is dynamic and ends with '\0' */
+	if (!len)
+		return strcmp(str, r->pattern) == 0;
+
+	return strncmp(str, r->pattern, len) == 0;
 }
 
 static int regex_match_front(char *str, struct regex *r, int len)
 {
-	if (len < r->len)
+	if (len && len < r->len)
 		return 0;
 
-	if (strncmp(str, r->pattern, r->len) == 0)
-		return 1;
-	return 0;
+	return strncmp(str, r->pattern, len) == 0;
 }
 
 static int regex_match_middle(char *str, struct regex *r, int len)
 {
-	if (strnstr(str, r->pattern, len))
-		return 1;
-	return 0;
+	if (!len)
+		return strstr(str, r->pattern) != NULL;
+
+	return strnstr(str, r->pattern, len) != NULL;
 }
 
 static int regex_match_end(char *str, struct regex *r, int len)
-- 
2.17.0

  parent reply	other threads:[~2018-05-11 19:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-11 19:49 [RFC][PATCH 00/10] tracing: Add triggers to trace_marker writes Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 01/10] tracing: Do not reference event data in post call triggers Steven Rostedt
2018-05-12 12:04   ` Masami Hiramatsu
2018-05-11 19:49 ` [RFC][PATCH 02/10] tracing: Add __find_event_file() to find event files without restrictions Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 03/10] tracing: Have event_trace_init() called by trace_init_tracefs() Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 04/10] tracing: Add brackets in ftrace event dynamic arrays Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 05/10] tracing: Do not show filter file for ftrace internal events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 06/10] tracing: Add trigger file for trace_markers tracefs/ftrace/print Steven Rostedt
2018-05-14  3:13   ` Namhyung Kim
2018-05-14 15:04     ` Steven Rostedt
2018-05-16  7:49       ` Namhyung Kim
2018-05-16 10:37         ` Steven Rostedt
2018-05-11 19:49 ` Steven Rostedt [this message]
2018-05-12 12:40   ` [RFC][PATCH 07/10] tracing: Have zero size length in filter logic be full string Masami Hiramatsu
2018-05-12 17:27     ` Steven Rostedt
2018-05-12 18:32   ` Yann Ylavic
2018-05-14  2:23     ` Namhyung Kim
2018-05-14 14:12     ` Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 08/10] tracing: Prevent further users of zero size static arrays in trace events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 09/10] tracing: Allow histogram triggers to access ftrace internal events Steven Rostedt
2018-05-11 19:49 ` [RFC][PATCH 10/10] tracing: Document trace_marker triggers Steven Rostedt

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