linux-kernel - [PATCH 3.16 204/294] modpost: expand pattern matching to support substring matches

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Message-ID: <lsq.1510009382.399037100@decadent.org.uk>
Date:   Mon, 06 Nov 2017 23:03:02 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Rusty Russell" <rusty@...tcorp.com.au>,
        "Paul Gortmaker" <paul.gortmaker@...driver.com>,
        "Arnd Bergmann" <arnd@...db.de>
Subject: [PATCH 3.16 204/294] modpost: expand pattern matching to support
 substring matches

3.16.50-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Paul Gortmaker <paul.gortmaker@...driver.com>

commit 09c20c032b0f753969ae778d9783d946f054d7fe upstream.

Currently the match() function supports a leading * to match any
prefix and a trailing * to match any suffix.  However there currently
is not a combination of both that can be used to target matches of
whole families of functions that share a common substring.

Here we expand the *foo and foo* match to also support *foo* with
the goal of targeting compiler generated symbol names that contain
strings like ".constprop." and ".isra."

Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 scripts/mod/modpost.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -798,6 +798,7 @@ static int number_prefix(const char *sym
  *   where the '1' can be any number including several digits.
  *   The $ syntax is for sections where ld append a dot number
  *   to make section name unique.
+ * "*foo*" will match a string that contains "foo"
  */
 static int match(const char *sym, const char * const pat[])
 {
@@ -806,8 +807,17 @@ static int match(const char *sym, const
 		p = *pat++;
 		const char *endp = p + strlen(p) - 1;
 
+		/* "*foo*" */
+		if (*p == '*' && *endp == '*') {
+			char *here, *bare = strndup(p + 1, strlen(p) - 2);
+
+			here = strstr(sym, bare);
+			free(bare);
+			if (here != NULL)
+				return 1;
+		}
 		/* "*foo" */
-		if (*p == '*') {
+		else if (*p == '*') {
 			if (strrcmp(sym, p + 1) == 0)
 				return 1;
 		}