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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	yrl.pp-manager.tt@hitachi.com, Oleg Nesterov <oleg@redhat.com>,
	Akinobu Mita <akinobu.mita@gmail.com>,
	David Howells <dhowells@redhat.com>,
	Ingo Molnar <mingo@redhat.com>,
	Tom Zanussi <tom.zanussi@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH 3/5] lib/string: Add a generic wildcard string matching function
Date: Thu, 16 May 2013 20:48:55 +0900	[thread overview]
Message-ID: <20130516114855.13508.34529.stgit@mhiramat-M0-7522> (raw)
In-Reply-To: <20130516114839.13508.92844.stgit@mhiramat-M0-7522>

Add strglobmatch() for generic wildcard string matching.
This code is originally from perf-tools. For porting in
the kernel, the limitation of the number of wildcards is
introduced, because of the limitation of the stack.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
---
 include/linux/string.h |    8 ++++
 lib/string.c           |   91 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index ac889c5..fcb1506 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -122,6 +122,14 @@ extern void argv_free(char **argv);
 extern bool sysfs_streq(const char *s1, const char *s2);
 extern int strtobool(const char *s, bool *res);
 
+/*
+ * Maximum number of wildcards in a glob pattern
+ * This limits the number of wildcards in a glob pattern, because
+ * more wildcards consume more kernel stack.
+ */
+#define MAX_GLOB_WILDCARDS	10
+extern bool strglobmatch(const char *glob, const char *str);
+
 #ifdef CONFIG_BINARY_PRINTF
 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
diff --git a/lib/string.c b/lib/string.c
index e5878de..640fb10 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -824,3 +824,94 @@ void *memchr_inv(const void *start, int c, size_t bytes)
 	return check_bytes8(start, value, bytes % 8);
 }
 EXPORT_SYMBOL(memchr_inv);
+
+/* Character class matching */
+static bool __match_charclass(const char *pat, char c, const char **npat)
+{
+	bool complement = false, ret = true;
+
+	if (*pat == '!') {
+		complement = true;
+		pat++;
+	}
+	if (*pat++ == c)	/* First character is special */
+		goto end;
+
+	while (*pat && *pat != ']') {	/* Matching */
+		if (*pat == '-' && *(pat + 1) != ']') {	/* Range */
+			if (*(pat - 1) <= c && c <= *(pat + 1))
+				goto end;
+			if (*(pat - 1) > *(pat + 1))
+				goto error;
+			pat += 2;
+		} else if (*pat++ == c)
+			goto end;
+	}
+	if (!*pat)
+		goto error;
+	ret = false;
+
+end:
+	while (*pat && *pat != ']')	/* Searching closing */
+		pat++;
+	if (!*pat)
+		goto error;
+	*npat = pat + 1;
+	return complement ? !ret : ret;
+
+error:
+	return false;
+}
+
+/* Glob pattern(wildcard and char-class) matching */
+static bool __match_glob(const char *pat, const char *str, int nest)
+{
+	if (nest > MAX_GLOB_WILDCARDS)
+		return false;
+
+	while (*str && *pat && *pat != '*') {
+		if (*pat == '?') {	/* Matches any single character */
+			str++;
+			pat++;
+			continue;
+		} else if (*pat == '[')	/* Character classes/Ranges */
+			if (__match_charclass(pat + 1, *str, &pat)) {
+				str++;
+				continue;
+			} else
+				return false;
+		else if (*pat == '\\') /* Escaped char match as normal char */
+			pat++;
+		if (*str++ != *pat++)
+			return false;
+	}
+	/* Check wild card */
+	if (*pat == '*') {
+		while (*pat == '*')
+			pat++;
+		if (!*pat)	/* Tail wild card matches all */
+			return true;
+		while (*str)
+			if (__match_glob(pat, str++, nest + 1))
+				return true;
+	}
+	return !*str && !*pat;
+}
+
+/**
+ * strglobmatch - glob expression pattern matching
+ * @pat: the pattern string to match
+ * @str: the target string to match
+ *
+ * This returns true if the @str matches @pat. @pat can includes wildcards
+ * ('*','?') and character classes ([CHARS], complementation and ranges are
+ * also supported). Also, this supports escape character ('\') to use special
+ * characters as normal character.
+ *
+ * Note: if @pat syntax is broken, this always returns false.
+ */
+bool strglobmatch(const char *pat, const char *str)
+{
+	return __match_glob(pat, str, 0);
+}
+EXPORT_SYMBOL(strglobmatch);


  parent reply	other threads:[~2013-05-16 11:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-16 11:48 [PATCH 0/5] Add glob pattern matching support on trigger and kprobe-event Masami Hiramatsu
2013-05-16 11:48 ` [PATCH 1/5] [BUGFIX] tracing: Returns -EBUSY when event_enable_func fails to get module Masami Hiramatsu
2013-05-16 14:58   ` Steven Rostedt
2013-05-16 11:48 ` [PATCH 2/5] perf: Reorder parameters of strglobmatch Masami Hiramatsu
2013-05-16 14:55   ` Steven Rostedt
2013-05-17  2:21     ` Masami Hiramatsu
2013-05-21  9:19       ` Arnaldo Carvalho de Melo
2013-05-21  9:49         ` Masami Hiramatsu
2013-05-16 11:48 ` Masami Hiramatsu [this message]
2013-05-16 11:48 ` [PATCH 4/5] tracing/kprobes: Allow user to delete kprobe events by wild cards Masami Hiramatsu
2013-05-16 11:49 ` [PATCH 5/5] tracing: Support enable/disable multiple events trigger " Masami Hiramatsu

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