tools lib traceevent: Introduce extend_token()

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>

1 files changed, 24 insertions, 26 deletions

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 7815b8d2eab..768fab5fbcb 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) {