tracing/user_events: Fix non-spaced field matching

[linux-2.6-block.git] / kernel / trace / trace_events_user.c

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 70d428c394b68dee53cc26a08c101945ef8587cd..82b191f33a28fe29d95bd04b13d23505ee96e708 100644 (file)
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1989,6 +1989,80 @@ static int user_event_set_tp_name(struct user_event *user)
        return 0;
 }
 
+/*
+ * Counts how many ';' without a trailing space are in the args.
+ */
+static int count_semis_no_space(char *args)
+{
+       int count = 0;
+
+       while ((args = strchr(args, ';'))) {
+               args++;
+
+               if (!isspace(*args))
+                       count++;
+       }
+
+       return count;
+}
+
+/*
+ * Copies the arguments while ensuring all ';' have a trailing space.
+ */
+static char *insert_space_after_semis(char *args, int count)
+{
+       char *fixed, *pos;
+       int len;
+
+       len = strlen(args) + count;
+       fixed = kmalloc(len + 1, GFP_KERNEL);
+
+       if (!fixed)
+               return NULL;
+
+       pos = fixed;
+
+       /* Insert a space after ';' if there is no trailing space. */
+       while (*args) {
+               *pos = *args++;
+
+               if (*pos++ == ';' && !isspace(*args))
+                       *pos++ = ' ';
+       }
+
+       *pos = '\0';
+
+       return fixed;
+}
+
+static char **user_event_argv_split(char *args, int *argc)
+{
+       char **split;
+       char *fixed;
+       int count;
+
+       /* Count how many ';' without a trailing space */
+       count = count_semis_no_space(args);
+
+       /* No fixup is required */
+       if (!count)
+               return argv_split(GFP_KERNEL, args, argc);
+
+       /* We must fixup 'field;field' to 'field; field' */
+       fixed = insert_space_after_semis(args, count);
+
+       if (!fixed)
+               return NULL;
+
+       /* We do a normal split afterwards */
+       split = argv_split(GFP_KERNEL, fixed, argc);
+
+       /* We can free since argv_split makes a copy */
+       kfree(fixed);
+
+       return split;
+}
+
 /*
  * Parses the event name, arguments and flags then registers if successful.
  * The name buffer lifetime is owned by this method for success cases only.
@@ -2012,7 +2086,7 @@ static int user_event_parse(struct user_event_group *group, char *name,
                return -EPERM;
 
        if (args) {
-               argv = argv_split(GFP_KERNEL, args, &argc);
+               argv = user_event_argv_split(args, &argc);
 
                if (!argv)
                        return -ENOMEM;