[PATCH 2/2] utilities: kernelscan: remove use of pcre, use regex instead

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Using pcre does not offer any extra benefit over regex and
requires an extra library dependency.  Remove pcre and replace
with regex.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/utilities/Makefile.am  |  1 -
 src/utilities/kernelscan.c | 34 +++++++++++++++-------------------
 2 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/src/utilities/Makefile.am b/src/utilities/Makefile.am
index 3160a35..9a47980 100644
--- a/src/utilities/Makefile.am
+++ b/src/utilities/Makefile.am
@@ -4,5 +4,4 @@ AM_CPPFLAGS = -Wall -Werror -Wextra -DDATAROOTDIR=\"$(datarootdir)\" \
 
 bin_PROGRAMS = kernelscan
 kernelscan_SOURCES = kernelscan.c
-kernelscan_LDFLAGS = -lpcre
 
diff --git a/src/utilities/kernelscan.c b/src/utilities/kernelscan.c
index 9dca440..10b51d6 100644
--- a/src/utilities/kernelscan.c
+++ b/src/utilities/kernelscan.c
@@ -23,9 +23,10 @@
 #include <string.h>
 #include <ctype.h>
 #include <unistd.h>
-
-#include <pcre.h>
+#include <sys/types.h>
+#include <regex.h>
 #include <json.h>
+
 #include "config.h"
 
 #define PARSER_OK		0
@@ -49,8 +50,8 @@ typedef enum {
 typedef struct {
         char *pattern;		/* pattern that we compare to kernel messages */
 	compare_mode cm;	/* 'r' regex or 's' string comparison */
-        pcre *re;		/* regex from pattern */
-        pcre_extra *extra;
+        regex_t compiled;	/* regex from pattern */
+	bool compiled_ok;	/* regex compiled OK */
 } klog_pattern;
 
 /*
@@ -270,9 +271,7 @@ static klog_pattern *klog_load(const char *table)
 
 	/* Now fetch json objects and compile regex */
 	for (i = 0; i < n; i++) {
-		const char *error;
 		const char *str;
-		int erroffset;
 		json_object *obj;
 #if JSON_HAS_GET_EX
 		json_object *obj_str;
@@ -320,15 +319,14 @@ static klog_pattern *klog_load(const char *table)
 
 		/* Pre-compile regular expressions to make things run a bit faster */
 		if (patterns[i].cm == COMPARE_REGEX) {
-			if ((patterns[i].re = pcre_compile(patterns[i].pattern, 0, &error, &erroffset, NULL)) == NULL) {
-				fprintf(stderr, "Regex %s failed to compile: %s.\n", patterns[i].pattern, error);
-				patterns[i].re = NULL;
+			int rc;
+
+			rc = regcomp(&patterns[i].compiled, patterns[i].pattern, REG_EXTENDED);
+			if (rc) {
+				fprintf(stderr, "Regex %s failed to compile: %d.\n", patterns[i].pattern, rc);
+				patterns[i].compiled_ok = false;
 			} else {
-				patterns[i].extra = pcre_study(patterns[i].re, 0, &error);
-				if (error != NULL) {
-					fprintf(stderr, "Regex %s failed to optimize: %s.\n", patterns[i].pattern, error);
-					patterns[i].re = NULL;
-				}
+				patterns[i].compiled_ok = true;
 			}
 		}
 	}
@@ -352,10 +350,9 @@ static bool klog_find(char *str, klog_pattern *patterns)
 				return true;
 			}
 		} else if (patterns[i].cm == COMPARE_REGEX) {
-			int vector[1];
-			if (pcre_exec(patterns[i].re, patterns[i].extra, str, strlen(str), 0, 0, vector, 1) == 0) {
+			if (patterns[i].compiled_ok &&
+			    (!regexec(&patterns[i].compiled, str, 0, NULL, 0)))
 				return true;
-			}
 		}
 	}
 
@@ -370,8 +367,7 @@ static void klog_free(klog_pattern *patterns)
 	int i;
 
 	for (i = 0; patterns[i].pattern; i++) {
-		pcre_free(patterns[i].re);
-		pcre_free(patterns[i].extra);
+		regfree(&patterns[i].compiled);
 		free(patterns[i].pattern);
 	}
 	free(patterns);
-- 
2.6.2