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>

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 7815b8d2eabdba4933aca1e911960715d209fe01..768fab5fbcb70a88c2c7caaa1cd00bfe984e6ac4 100644 (file)
--- 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) {