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Subject[PATCH 07/20] tools lib traceevent: Introduce extend_token()
Date
From: Namhyung Kim <namhyung.kim@lge.com>

The __read_token() function has some duplicated code to handle
internal buffer overflow. Factor them out to new extend_token().

According to the man pages of realloc/free(3), they can handle NULL
pointer input so that it can be ended up to compact the code. Also
handle error path correctly.

Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1333940074-19052-4-git-send-email-namhyung.kim@lge.com
[rostedt@goodmis.org: added some extra whitespace]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/lib/traceevent/event-parse.c | 50 +++++++++++++++++-------------------
1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 7815b8d..768fab5 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -781,6 +781,25 @@ int pevent_peek_char(void)
return __peek_char();
}

+static int extend_token(char **tok, char *buf, int size)
+{
+ char *newtok = realloc(*tok, size);
+
+ if (!newtok) {
+ free(*tok);
+ *tok = NULL;
+ return -1;
+ }
+
+ if (!*tok)
+ strcpy(newtok, buf);
+ else
+ strcat(newtok, buf);
+ *tok = newtok;
+
+ return 0;
+}
+
static enum event_type force_token(const char *str, char **tok);

static enum event_type __read_token(char **tok)
@@ -865,17 +884,10 @@ static enum event_type __read_token(char **tok)
do {
if (i == (BUFSIZ - 1)) {
buf[i] = 0;
- if (*tok) {
- *tok = realloc(*tok, tok_size + BUFSIZ);
- if (!*tok)
- return EVENT_NONE;
- strcat(*tok, buf);
- } else
- *tok = strdup(buf);
+ tok_size += BUFSIZ;

- if (!*tok)
+ if (extend_token(tok, buf, tok_size) < 0)
return EVENT_NONE;
- tok_size += BUFSIZ;
i = 0;
}
last_ch = ch;
@@ -914,17 +926,10 @@ static enum event_type __read_token(char **tok)
while (get_type(__peek_char()) == type) {
if (i == (BUFSIZ - 1)) {
buf[i] = 0;
- if (*tok) {
- *tok = realloc(*tok, tok_size + BUFSIZ);
- if (!*tok)
- return EVENT_NONE;
- strcat(*tok, buf);
- } else
- *tok = strdup(buf);
+ tok_size += BUFSIZ;

- if (!*tok)
+ if (extend_token(tok, buf, tok_size) < 0)
return EVENT_NONE;
- tok_size += BUFSIZ;
i = 0;
}
ch = __read_char();
@@ -933,14 +938,7 @@ static enum event_type __read_token(char **tok)

out:
buf[i] = 0;
- if (*tok) {
- *tok = realloc(*tok, tok_size + i);
- if (!*tok)
- return EVENT_NONE;
- strcat(*tok, buf);
- } else
- *tok = strdup(buf);
- if (!*tok)
+ if (extend_token(tok, buf, tok_size + i + 1) < 0)
return EVENT_NONE;

if (type == EVENT_ITEM) {
--
1.7.9.2.358.g22243


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