libata: glob_match for ata_device_blacklist (v2)

Replace rudimentry pattern matching with more capable shell-style globbing.
This will enable shrinking ata_device_blacklist[] table in subsequent patches,
and helps with future editions to the table, such as matching only the end
of a firmware revision string etc..

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 57 insertions, 21 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index ddf8e486278..f8c72a1867f 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4326,29 +4326,65 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
         { }
 };
 
-static int strn_pattern_cmp(const char *patt, const char *name, int wildchar)
+/**
+ *      glob_match - match a text string against a glob-style pattern
+ *      @text: the string to be examined
+ *      @pattern: the glob-style pattern to be matched against
+ *
+ *      Either/both of text and pattern can be empty strings.
+ *
+ *      Match text against a glob-style pattern, with wildcards and simple sets:
+ *
+ *              ?       matches any single character.
+ *              *       matches any run of characters.
+ *              [xyz]   matches a single character from the set: x, y, or z.
+ *
+ *      Note: hyphenated ranges [0-9] are _not_ supported here.
+ *      The special characters ?, [, or *, can be matched using a set, eg. [*]
+ *
+ *      Example patterns:  "SD1?",  "SD1[012345]",  "*R0",  SD*1?[012]*xx"
+ *
+ *      This function uses one level of recursion per '*' in pattern.
+ *      Since it calls _nothing_ else, and has _no_ explicit local variables,
+ *      this will not cause stack problems for any reasonable use here.
+ *
+ *      RETURNS:
+ *      0 on match, 1 otherwise.
+ */
+static int glob_match (const char *text, const char *pattern)
 {
-        const char *p;
-        int len;
-
-        /*
-         * check for trailing wildcard: *\0
-         */
-        p = strchr(patt, wildchar);
-        if (p && ((*(p + 1)) == 0))
-                len = p - patt;
-        else {
-                len = strlen(name);
-                if (!len) {
-                        if (!*patt)
-                                return 0;
-                        return -1;
+        do {
+                /* Match single character or a '?' wildcard */
+                if (*text == *pattern || *pattern == '?') {
+                        if (!*pattern++)
+                                return 0;  /* End of both strings: match */
+                } else {
+                        /* Match single char against a '[' bracketed ']' pattern set */
+                        if (!*text || *pattern != '[')
+                                break;  /* Not a pattern set */
+                        while (*++pattern && *pattern != ']' && *text != *pattern);
+                        if (!*pattern || *pattern == ']')
+                                return 1;  /* No match */
+                        while (*pattern && *pattern++ != ']');
+                }
+        } while (*++text && *pattern);
+
+        /* Match any run of chars against a '*' wildcard */
+        if (*pattern == '*') {
+                if (!*++pattern)
+                        return 0;  /* Match: avoid recursion at end of pattern */
+                /* Loop to handle additional pattern chars after the wildcard */
+                while (*text) {
+                        if (glob_match(text, pattern) == 0)
+                                return 0;  /* Remainder matched */
+                        ++text;  /* Absorb (match) this char and try again */
                 }
         }
-
-        return strncmp(patt, name, len);
+        if (!*text && !*pattern)
+                return 0;  /* End of both strings: match */
+        return 1;  /* No match */
 }
-
+ 
 static unsigned long ata_dev_blacklisted(const struct ata_device *dev)
 {
         unsigned char model_num[ATA_ID_PROD_LEN + 1];
@@ -4359,10 +4395,10 @@ static unsigned long ata_dev_blacklisted(const struct ata_device *dev)
         ata_id_c_string(dev->id, model_rev, ATA_ID_FW_REV, sizeof(model_rev));
 
         while (ad->model_num) {
-                if (!strn_pattern_cmp(ad->model_num, model_num, '*')) {
+                if (!glob_match(model_num, ad->model_num)) {
                         if (ad->model_rev == NULL)
                                 return ad->horkage;
-                        if (!strn_pattern_cmp(ad->model_rev, model_rev, '*'))
+                        if (!glob_match(model_rev, ad->model_rev))
                                 return ad->horkage;
                 }
                 ad++;