tools lib traceevent: Use asprintf when possible

It makes the code clearer and less error prone.

clearer:
- less code
- the code is now using the same format to create strings dynamically

less error prone:
- no magic number +2 +9 +5 to compute the size
- no copy&paste of the strings to compute the size and to concatenate

The function `asprintf` is not POSIX standard but the program
was already using it. Later it can be decided to use only POSIX
functions, then we can easly replace all the `asprintf(3)` with a local
implementation of that function.

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Federico Vaga <federico.vaga@vaga.pv.it>
Link: http://lkml.kernel.org/r/20170802221558.9684-2-federico.vaga@vaga.pv.it
Link: http://lkml.kernel.org/r/20180112004822.686281649@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 315df0a70265..2410afdcbcfe 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -287,12 +287,10 @@ find_event(struct pevent *pevent, struct event_list **events,
 		sys_name = NULL;
 	}
 
-	reg = malloc(strlen(event_name) + 3);
-	if (reg == NULL)
+	ret = asprintf(&reg, "^%s$", event_name);
+	if (ret < 0)
 		return PEVENT_ERRNO__MEM_ALLOC_FAILED;
 
-	sprintf(reg, "^%s$", event_name);
-
 	ret = regcomp(&ereg, reg, REG_ICASE|REG_NOSUB);
 	free(reg);
 
@@ -300,13 +298,12 @@ find_event(struct pevent *pevent, struct event_list **events,
 		return PEVENT_ERRNO__INVALID_EVENT_NAME;
 
 	if (sys_name) {
-		reg = malloc(strlen(sys_name) + 3);
-		if (reg == NULL) {
+		ret = asprintf(&reg, "^%s$", sys_name);
+		if (ret < 0) {
 			regfree(&ereg);
 			return PEVENT_ERRNO__MEM_ALLOC_FAILED;
 		}
 
-		sprintf(reg, "^%s$", sys_name);
 		ret = regcomp(&sreg, reg, REG_ICASE|REG_NOSUB);
 		free(reg);
 		if (ret) {