From: "Du, Changbin" <changbin...@gmail.com>

This patch add wildcard '*'(matches zero or more characters) and '?'
(matches one character) support when qurying debug flags.

Now we can open debug messages using keywords. eg:
1. open debug logs in all usb drivers
    echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
2.  open debug logs for usb xhci code
    echo "file *xhci* +p" > <debugfs>/dynamic_debug/control

Signed-off-by: Du, Changbin <changbin...@gmail.com>
---
changes since v2:
    remove the goto statements.
    code style issue.
---
 lib/dynamic_debug.c | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 5 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index c37aeac..b166d19 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -127,6 +127,43 @@ static void vpr_info_dq(const struct ddebug_query *query, 
const char *msg)
                 query->first_lineno, query->last_lineno);
 }
 
+/* check if the string matches given pattern which includes wildcards */
+static bool match_pattern(const char *pattern, const char *string)
+{
+       const char *s = string,
+                  *p = pattern;
+       bool star = 0;
+
+       while (*s) {
+               switch (*p) {
+               case '?':
+                       ++s, ++p;
+                       break;
+               case '*':
+                       star = true;
+                       string = s;
+                       if (!*++p)
+                               return true;
+                       pattern = p;;
+                       break;
+               default:
+                       if (*s != *p) {
+                               if (!star)
+                                       return false;
+                               string++;
+                               s = string;
+                               p = pattern;
+                               break;
+                       }
+                       ++s, ++p;
+               }
+       }
+
+       if (*p == '*')
+               ++p;
+       return !*p;
+}
+
 /*
  * Search the tables for _ddebug's which match the given `query' and
  * apply the `flags' and `mask' to them.  Returns number of matching
@@ -147,7 +184,7 @@ static int ddebug_change(const struct ddebug_query *query,
        list_for_each_entry(dt, &ddebug_tables, link) {
 
                /* match against the module name */
-               if (query->module && strcmp(query->module, dt->mod_name))
+               if (query->module && !match_pattern(query->module, 
dt->mod_name))
                        continue;
 
                for (i = 0; i < dt->num_ddebugs; i++) {
@@ -155,14 +192,16 @@ static int ddebug_change(const struct ddebug_query *query,
 
                        /* match against the source filename */
                        if (query->filename &&
-                           strcmp(query->filename, dp->filename) &&
-                           strcmp(query->filename, kbasename(dp->filename)) &&
-                           strcmp(query->filename, trim_prefix(dp->filename)))
+                           !match_pattern(query->filename, dp->filename) &&
+                           !match_pattern(query->filename,
+                                          kbasename(dp->filename)) &&
+                           !match_pattern(query->filename,
+                                          trim_prefix(dp->filename)))
                                continue;
 
                        /* match against the function */
                        if (query->function &&
-                           strcmp(query->function, dp->function))
+                           !match_pattern(query->function, dp->function))
                                continue;
 
                        /* match against the format */
-- 
1.8.1.2

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