Add work around for event output bug in older kernels

Older kernels have a bug that prints out the macro name instead of
what it should represent. This breaks parsing the data from userspace.
This especially affects the mac80211 trace events.

This adds a work around in the tool to handle the bug when executed
on older kernels.

See Linux kernel commit 811cb50baf63461ce0bdb234927046131fc7fa8b
for details.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

1 files changed, 48 insertions, 1 deletions

diff --git a/parse-events.c b/parse-events.c
index fe683c9..df6ad6e 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -463,6 +463,26 @@ static enum event_type get_type(int ch)
         return EVENT_OP;
 }
 
+static void __push_char(char c)
+{
+        if (input_buf_ptr <= 0)
+                die("too much pushback");
+        input_buf[--input_buf_ptr] = c;
+}
+
+static void __push_str(char *s)
+{
+        char *e = s;
+
+        while (*e++)
+                /* nothing */;
+        e--;
+        while (s != e) {
+                e--;
+                __push_char(*e);
+        }
+}
+
 static int __read_char(void)
 {
         if (input_buf_ptr >= input_buf_siz)
@@ -622,6 +642,33 @@ static enum event_type __read_token(char **tok)
         if (!*tok)
                 return EVENT_NONE;
 
+        if (type == EVENT_ITEM) {
+                /*
+                 * Older versions of the kernel has a bug that
+                 * creates invalid symbols and will break the mac80211
+                 * parsing. This is a work around to that bug.
+                 *
+                 * See Linux kernel commit:
+                 *  811cb50baf63461ce0bdb234927046131fc7fa8b
+                 */
+                if (strcmp(*tok, "LOCAL_PR_FMT") == 0) {
+                        free(*tok);
+                        *tok = NULL;
+                        __push_str("\"\%s\" ");
+                        return __read_token(tok);
+                } else if (strcmp(*tok, "STA_PR_FMT") == 0) {
+                        free(*tok);
+                        *tok = NULL;
+                        __push_str("\" sta:%pM\" ");
+                        return __read_token(tok);
+                } else if (strcmp(*tok, "VIF_PR_FMT") == 0) {
+                        free(*tok);
+                        *tok = NULL;
+                        __push_str("\" vif:%p(%d)\" ");
+                        return __read_token(tok);
+                }
+        }
+
         return type;
 }
 
@@ -2015,7 +2062,7 @@ static int event_read_print(struct event *event)
         if (type == EVENT_NONE)
                 return 0;
 
-        /* Handle concatination of print lines */
+        /* Handle concatenation of print lines */
         if (type == EVENT_DQUOTE) {
                 char *cat;