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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Subject: [RFC][PATCH 2/7] implement memmem()
Date: Thu,  5 Feb 2015 19:56:35 +0000	[thread overview]
Message-ID: <1423166200-1800-2-git-send-email-viro@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20150205194914.GR29656@ZenIV.linux.org.uk>

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 include/linux/string.h |  1 +
 lib/string.c           | 34 ++++++++++++++++++++++------------
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index 2e22a2e..87f9fba 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -75,6 +75,7 @@ extern char * strstr(const char *, const char *);
 #endif
 #ifndef __HAVE_ARCH_STRNSTR
 extern char * strnstr(const char *, const char *, size_t);
+extern void * memmem(const void *, size_t, const void *, size_t);
 #endif
 #ifndef __HAVE_ARCH_STRLEN
 extern __kernel_size_t strlen(const char *);
diff --git a/lib/string.c b/lib/string.c
index 1006330..2035dbe 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -740,27 +740,37 @@ EXPORT_SYMBOL(strstr);
 #endif
 
 #ifndef __HAVE_ARCH_STRNSTR
+
 /**
- * strnstr - Find the first substring in a length-limited string
+ * memmem - Find the first length-limited substring in a length-limited string
  * @s1: The string to be searched
+ * @len1: the maximum number of characters to search
  * @s2: The string to search for
- * @len: the maximum number of characters to search
+ * @len2: the length of the string being searched
  */
-char *strnstr(const char *s1, const char *s2, size_t len)
+void *memmem(const void *s1, size_t len1, const void *s2, size_t len2)
 {
-	size_t l2;
-
-	l2 = strlen(s2);
-	if (!l2)
-		return (char *)s1;
-	while (len >= l2) {
-		len--;
-		if (!memcmp(s1, s2, l2))
-			return (char *)s1;
+	if (!len2)
+		return (void *)s1;
+	while (len1 >= len2) {
+		len1--;
+		if (!memcmp(s1, s2, len2))
+			return (void *)s1;
 		s1++;
 	}
 	return NULL;
 }
+EXPORT_SYMBOL(memmem);
+/**
+ * strnstr - Find the first substring in a length-limited string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ * @len: the maximum number of characters to search
+ */
+char *strnstr(const char *s1, const char *s2, size_t len)
+{
+	return memmem(s1, len, s2, strlen(s2));
+}
 EXPORT_SYMBOL(strnstr);
 #endif
 
-- 
2.1.4


  parent reply	other threads:[~2015-02-05 19:56 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-05 19:49 [RFC][PATCHES] constifying ftrace globs Al Viro
2015-02-05 19:56 ` [RFC][PATCH 1/7] trace: fix the glob match in __unregister_ftrace_function_probe() Al Viro
2015-02-05 20:43   ` Steven Rostedt
2015-02-05 22:30     ` Al Viro
2015-02-05 22:52       ` Steven Rostedt
2015-02-05 19:56 ` Al Viro [this message]
2015-02-05 19:56 ` [RFC][PATCH 3/7] trace_events_filter.c: switch to memcmp() and memmem() for matching Al Viro
2015-02-05 19:56 ` [RFC][PATCH 4/7] ftrace: switch matching to memcmp() and memmem() Al Viro
2015-02-05 19:56 ` [RFC][PATCH 5/7] trace: make filter_parse_regex() provide the length of substring to compare with Al Viro
2015-02-05 21:29   ` Steven Rostedt
2015-02-05 21:44     ` Al Viro
2015-02-05 22:07       ` Steven Rostedt
2015-02-05 22:46         ` Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 1/7] trace: fix the glob match in __unregister_ftrace_function_probe() Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 2/7] implement memmem() Al Viro
2015-02-06 16:19             ` Steven Rostedt
2015-02-06 22:30             ` Rasmus Villemoes
2015-02-06 22:55               ` Steven Rostedt
2015-02-06 23:14                 ` Rasmus Villemoes
2015-02-06  4:00           ` [RFC][PATCH v2 3/7] trace_events_filter.c: switch to memcmp() and memmem() for matching Al Viro
2015-02-06 16:24             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 4/7] ftrace: switch matching to memcmp() and memmem() Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 5/7] trace: make filter_parse_regex() provide the length of substring to compare with Al Viro
2015-02-06 18:55             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 6/7] trace: constify filter_parse_regex(), match_records(), ftrace_match() and ftrace_match_record() Al Viro
2015-02-06 18:56             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 7/7] trace: constify glob arguments all way up to ftrace_function_set_regexp() Al Viro
2015-02-05 19:56 ` [RFC][PATCH 6/7] trace: constify filter_parse_regex(), match_records(), ftrace_match() and ftrace_match_record() Al Viro
2015-02-05 21:31   ` Steven Rostedt
2015-02-05 19:56 ` [RFC][PATCH 7/7] trace: constify glob arguments all way up to ftrace_function_set_regexp() Al Viro
2020-01-24 23:45 ` [RFC][PATCHES] constifying ftrace globs Steven Rostedt

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