From: Li Zefan <lizf@cn.fujitsu.com>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Wenji Huang <wenji.huang@oracle.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 4/7] lib: Introduce strnstr()
Date: Mon, 14 Dec 2009 11:58:10 +0800 [thread overview]
Message-ID: <4B25B7D2.8090505@cn.fujitsu.com> (raw)
In-Reply-To: <4B25B797.1040201@cn.fujitsu.com>
It differs strstr() in that it limits the length to be searched
in the first string.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
include/linux/string.h | 5 ++++-
lib/string.c | 27 ++++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/include/linux/string.h b/include/linux/string.h
index b850886..fa6a5ba 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -64,7 +64,10 @@ extern char * strrchr(const char *,int);
#endif
extern char * __must_check strstrip(char *);
#ifndef __HAVE_ARCH_STRSTR
-extern char * strstr(const char *,const char *);
+extern char * strstr(const char *, const char *);
+#endif
+#ifndef __HAVE_ARCH_STRNSTR
+extern char * strnstr(const char *, const char *, 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 e96421a..a5fff51 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -656,7 +656,7 @@ EXPORT_SYMBOL(memscan);
*/
char *strstr(const char *s1, const char *s2)
{
- int l1, l2;
+ size_t l1, l2;
l2 = strlen(s2);
if (!l2)
@@ -673,6 +673,31 @@ char *strstr(const char *s1, const char *s2)
EXPORT_SYMBOL(strstr);
#endif
+#ifndef __HAVE_ARCH_STRNSTR
+/**
+ * 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)
+{
+ size_t l1 = len, l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ while (l1 >= l2) {
+ l1--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(strnstr);
+#endif
+
#ifndef __HAVE_ARCH_MEMCHR
/**
* memchr - Find a character in an area of memory.
--
1.6.3
next prev parent reply other threads:[~2009-12-14 3:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-14 3:57 [PATCH 0/7] tracing: Fix bugs in string filters Li Zefan
2009-12-14 3:57 ` [PATCH 1/7] ftrace: Fix MATCH_END_ONLY function filter Li Zefan
2009-12-14 3:57 ` [PATCH 2/7] tracing/filters: Fix MATCH_FRONT_ONLY filter matching Li Zefan
2009-12-14 3:57 ` [PATCH 3/7] tracing/filters: Fix MATCH_END_ONLY " Li Zefan
2009-12-14 3:58 ` Li Zefan [this message]
2009-12-14 3:58 ` [PATCH 5/7] tracing/filters: Fix MATCH_MIDDLE_ONLY " Li Zefan
2009-12-14 3:58 ` [PATCH 6/7] tracing/filters: Fix MATCH_END_ONLY filter matching for PTR_STRING Li Zefan
2009-12-14 3:59 ` [PATCH 7/7] tracing/filters: Add comment for match callbacks Li Zefan
2009-12-14 12:39 ` [PATCH 0/7] tracing: Fix bugs in string filters Frederic Weisbecker
2009-12-21 1:28 ` Li Zefan
2010-01-14 2:52 [PATCH 0/7][RESEND] " Li Zefan
2010-01-14 2:53 ` [PATCH 4/7] lib: Introduce strnstr() Li Zefan
2010-01-16 11:12 ` Alex Riesen
2010-01-18 14:53 ` Steven Rostedt
2010-01-18 15:56 ` Alex Riesen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4B25B7D2.8090505@cn.fujitsu.com \
--to=lizf@cn.fujitsu.com \
--cc=fweisbec@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rostedt@goodmis.org \
--cc=wenji.huang@oracle.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).