2 files changed, 157 insertions, 25 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 86bcff94791a..8d0db6018fe4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -702,20 +702,29 @@ struct event_subsystem {
 };
 
 struct filter_pred;
+struct regex;
 
 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
                                  int val1, int val2);
 
+typedef int (*regex_match_func)(char *str, struct regex *r, int len);
+
+struct regex {
+        char                    pattern[MAX_FILTER_STR_VAL];
+        int                     len;
+        int                     field_len;
+        regex_match_func        match;
+};
+
 struct filter_pred {
-        filter_pred_fn_t fn;
-        u64 val;
-        char str_val[MAX_FILTER_STR_VAL];
-        int str_len;
-        char *field_name;
-        int offset;
-        int not;
-        int op;
-        int pop_n;
+        filter_pred_fn_t        fn;
+        u64                     val;
+        struct regex            regex;
+        char                    *field_name;
+        int                     offset;
+        int                     not;
+        int                     op;
+        int                     pop_n;
 };
 
 extern void print_event_filter(struct ftrace_event_call *call,
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 189663d82aa7..d3c94c139567 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -195,9 +195,9 @@ static int filter_pred_string(struct filter_pred *pred, void *event,
         char *addr = (char *)(event + pred->offset);
         int cmp, match;
 
-        cmp = strncmp(addr, pred->str_val, pred->str_len);
+        cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
 
-        match = (!cmp) ^ pred->not;
+        match = cmp ^ pred->not;
 
         return match;
 }
@@ -209,9 +209,9 @@ static int filter_pred_pchar(struct filter_pred *pred, void *event,
         char **addr = (char **)(event + pred->offset);
         int cmp, match;
 
-        cmp = strncmp(*addr, pred->str_val, pred->str_len);
+        cmp = pred->regex.match(*addr, &pred->regex, pred->regex.field_len);
 
-        match = (!cmp) ^ pred->not;
+        match = cmp ^ pred->not;
 
         return match;
 }
@@ -235,9 +235,9 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event,
         char *addr = (char *)(event + str_loc);
         int cmp, match;
 
-        cmp = strncmp(addr, pred->str_val, str_len);
+        cmp = pred->regex.match(addr, &pred->regex, str_len);
 
-        match = (!cmp) ^ pred->not;
+        match = cmp ^ pred->not;
 
         return match;
 }
@@ -248,6 +248,126 @@ static int filter_pred_none(struct filter_pred *pred, void *event,
         return 0;
 }
 
+/* Basic regex callbacks */
+static int regex_match_full(char *str, struct regex *r, int len)
+{
+        if (strncmp(str, r->pattern, len) == 0)
+                return 1;
+        return 0;
+}
+
+static int regex_match_front(char *str, struct regex *r, int len)
+{
+        if (strncmp(str, r->pattern, len) == 0)
+                return 1;
+        return 0;
+}
+
+static int regex_match_middle(char *str, struct regex *r, int len)
+{
+        if (strstr(str, r->pattern))
+                return 1;
+        return 0;
+}
+
+static int regex_match_end(char *str, struct regex *r, int len)
+{
+        char *ptr = strstr(str, r->pattern);
+
+        if (ptr && (ptr[r->len] == 0))
+                return 1;
+        return 0;
+}
+
+enum regex_type {
+        MATCH_FULL,
+        MATCH_FRONT_ONLY,
+        MATCH_MIDDLE_ONLY,
+        MATCH_END_ONLY,
+};
+
+/*
+ * Pass in a buffer containing a regex and this function will
+ * set search to point to the search part of the buffer and
+ * return the type of search it is (see enum above).
+ * This does modify buff.
+ *
+ * Returns enum type.
+ *  search returns the pointer to use for comparison.
+ *  not returns 1 if buff started with a '!'
+ *     0 otherwise.
+ */
+static enum regex_type
+filter_parse_regex(char *buff, int len, char **search, int *not)
+{
+        int type = MATCH_FULL;
+        int i;
+
+        if (buff[0] == '!') {
+                *not = 1;
+                buff++;
+                len--;
+        } else
+                *not = 0;
+
+        *search = buff;
+
+        for (i = 0; i < len; i++) {
+                if (buff[i] == '*') {
+                        if (!i) {
+                                *search = buff + 1;
+                                type = MATCH_END_ONLY;
+                        } else {
+                                if (type == MATCH_END_ONLY)
+                                        type = MATCH_MIDDLE_ONLY;
+                                else
+                                        type = MATCH_FRONT_ONLY;
+                                buff[i] = 0;
+                                break;
+                        }
+                }
+        }
+
+        return type;
+}
+
+static int filter_build_regex(struct filter_pred *pred)
+{
+        struct regex *r = &pred->regex;
+        char *search, *dup;
+        enum regex_type type;
+        int not;
+
+        type = filter_parse_regex(r->pattern, r->len, &search, &not);
+        dup = kstrdup(search, GFP_KERNEL);
+        if (!dup)
+                return -ENOMEM;
+
+        strcpy(r->pattern, dup);
+        kfree(dup);
+
+        r->len = strlen(r->pattern);
+
+        switch (type) {
+        case MATCH_FULL:
+                r->match = regex_match_full;
+                break;
+        case MATCH_FRONT_ONLY:
+                r->match = regex_match_front;
+                break;
+        case MATCH_MIDDLE_ONLY:
+                r->match = regex_match_middle;
+                break;
+        case MATCH_END_ONLY:
+                r->match = regex_match_end;
+                break;
+        }
+
+        pred->not ^= not;
+
+        return 0;
+}
+
 /* return 1 if event matches, 0 otherwise (discard) */
 int filter_match_preds(struct ftrace_event_call *call, void *rec)
 {
@@ -394,7 +514,7 @@ static void filter_clear_pred(struct filter_pred *pred)
 {
         kfree(pred->field_name);
         pred->field_name = NULL;
-        pred->str_len = 0;
+        pred->regex.len = 0;
 }
 
 static int filter_set_pred(struct filter_pred *dest,
@@ -658,21 +778,24 @@ static int filter_add_pred(struct filter_parse_state *ps,
         }
 
         if (is_string_field(field)) {
-                pred->str_len = field->size;
+                ret = filter_build_regex(pred);
+                if (ret)
+                        return ret;
 
-                if (field->filter_type == FILTER_STATIC_STRING)
+                if (field->filter_type == FILTER_STATIC_STRING) {
                         fn = filter_pred_string;
-                else if (field->filter_type == FILTER_DYN_STRING)
-                        fn = filter_pred_strloc;
+                        pred->regex.field_len = field->size;
+                } else if (field->filter_type == FILTER_DYN_STRING)
+                                fn = filter_pred_strloc;
                 else {
                         fn = filter_pred_pchar;
-                        pred->str_len = strlen(pred->str_val);
+                        pred->regex.field_len = strlen(pred->regex.pattern);
                 }
         } else {
                 if (field->is_signed)
-                        ret = strict_strtoll(pred->str_val, 0, &val);
+                        ret = strict_strtoll(pred->regex.pattern, 0, &val);
                 else
-                        ret = strict_strtoull(pred->str_val, 0, &val);
+                        ret = strict_strtoull(pred->regex.pattern, 0, &val);
                 if (ret) {
                         parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
                         return -EINVAL;
@@ -1042,8 +1165,8 @@ static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
                 return NULL;
         }
 
-        strcpy(pred->str_val, operand2);
-        pred->str_len = strlen(operand2);
+        strcpy(pred->regex.pattern, operand2);
+        pred->regex.len = strlen(pred->regex.pattern);
 
         pred->op = op;