aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorFrederic Weisbecker <fweisbec@gmail.com>2009-05-03 03:03:57 +0200
committerIngo Molnar <mingo@elte.hu>2009-05-07 10:05:57 +0200
commit5928c3cc0ffcb6894bbab6be591b7ae1786b2d87 (patch)
tree75503a660dafe84dcd434912c5a0bdf97cad3c8a
parente8808c1019b048a43686dbd25c188a035842c2e2 (diff)
tracing/filters: support for operator reserved characters in strings
When we set a filter for an event, such as: echo "name == my_lock_name" > \ /debug/tracing/events/lockdep/lock_acquired/filter then the following order of token type is parsed: - space - operator - parentheses - operand Because the operators and parentheses have a higher precedence than the operand characters, which is normal, then we can't use any string containing such special characters: ()=<>!&| To get this support and also avoid ambiguous intepretation from the parser or the human, we can do it using double quotes so that we keep the usual languages habits. Then after this patch you can still declare string condition like before: echo name == myname But if you want to compare against a string containing an operator character, you can use double quotes: echo 'name == "&myname"' Don't forget to include the whole expression into single quotes or the double ones will be eaten by echo. [ Impact: support strings with special characters for tracing filters ] Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
-rw-r--r--kernel/trace/trace_events_filter.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 01c76eb3e16..8c62e5bdff0 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -851,10 +851,19 @@ static void postfix_clear(struct filter_parse_state *ps)
static int filter_parse(struct filter_parse_state *ps)
{
+ int in_string = 0;
int op, top_op;
char ch;
while ((ch = infix_next(ps))) {
+ if (ch == '"') {
+ in_string ^= 1;
+ continue;
+ }
+
+ if (in_string)
+ goto parse_operand;
+
if (isspace(ch))
continue;
@@ -908,6 +917,7 @@ static int filter_parse(struct filter_parse_state *ps)
}
continue;
}
+parse_operand:
if (append_operand_char(ps, ch)) {
parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
return -EINVAL;