From: Frédéric Marchal <fmarchal@users.sourceforge.net>
Date: Sat, 10 Mar 2012 11:01:25 +0000 (+0100)
Subject: Accept subpatterns in the host alias
X-Git-Tag: v2.3.3-pre1~18
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a16cb22a92d21fa6a7008f83453e404d20caf608;p=thirdparty%2Fsarg.git

Accept subpatterns in the host alias

Both the sed (\1) and perl ($1) subpatterns are accepted. Only 9
subpatterns are taken into account.
---

diff --git a/sarg.conf b/sarg.conf
index c3b44a1..30a0e45 100644
--- a/sarg.conf
+++ b/sarg.conf
@@ -753,6 +753,9 @@
 #      IPv6 addresses.
 #      Regular expressions can also be used if sarg was compiled with libpcre.
 #      A regular expression is formated as re:/regexp/ alias
+#      The regexp is a perl regular expression (see man perlre).
+#      Subpatterns are allowed in the alias. Sarg recognizes sed (\1) or perl ($1)
+#      subpatterns. Only 9 subpatterns are allowed in the replacement string.
 #
 #      Example:
 #      *.gstatic.com
@@ -763,4 +766,5 @@
 #      *.mail.live.com
 #      65.52.00.00/14 *.mail.live.com
 #      re:/\.dropbox\.com(:443)?/ dropbox
+#      re:/([\w-]+)\.(\w*[a-zA-Z]\w*)(?::\d+)?$/\1.\2
 #hostalias /usr/local/sarg/hostalias
diff --git a/url.c b/url.c
index 668e063..ec5b436 100644
--- a/url.c
+++ b/url.c
@@ -96,6 +96,8 @@ struct hostalias_regex
 	pcre *Re;
 	//! The replacement name.
 	const char *Alias;
+	//! \c True if this regular expression contains at least one subpattern
+	bool SubPartern;
 };
 #endif
 
@@ -455,6 +457,7 @@ static int Alias_StoreRegexp(char *buf)
 	char *Replace;
 	int len;
 	char *tmp;
+	int i;
 	
 	// find the pattern
 	Delimiter=*buf++;
@@ -503,6 +506,14 @@ static int Alias_StoreRegexp(char *buf)
 	tmp[len+1]='\0';
 	new_alias->Alias=tmp;
 	
+	new_alias->SubPartern=false;
+	for (i=1 ; tmp[i] ; i++)
+		// both the sed \1 and the perl $1 replacement operators are accepted
+		if ((tmp[i]=='\\' || tmp[i]=='$') && isdigit(tmp[i+1])) {
+			new_alias->SubPartern=true;
+			break;
+		}
+	
 	// chain it
 	prev_alias=&FirstAliasRe;
 	for (alias=FirstAliasRe ; alias ; alias=alias->Next)
@@ -755,20 +766,64 @@ static const char *alias_url_ipv6(const char *url,unsigned short int *ipv6)
 /*!
 Replace the host name by its alias if it is in our list.
 
-\param url The host name.
+\param url_ptr A pointer to the host name to match. It is replaced
+by a pointer to the alias if a match is found.
 
-\return The pointer to the host name or its alias.
+\return \c True if a match is found or \c false if it failed.
+
+\warning The function is not thread safe as it may return a static
+internal buffer.
 */
-static const char *alias_url_regex(const char *url)
+static bool alias_url_regex(const char **url_ptr)
 {
 	struct hostalias_regex *alias;
+	int nmatches;
+	const char *url;
+	int url_len;
+	int ovector[30];//size must be a multiple of 3
+	static char Replacement[1024];
+	const char *str;
+	int i;
+	int sub;
+	int repl_idx;
 
+	url=*url_ptr;
+	url_len=strlen(url);
 	for (alias=FirstAliasRe ; alias ; alias=alias->Next) {
-		if (pcre_exec(alias->Re,NULL,url,strlen(url),0,0,NULL,0)==0) {
-			return(alias->Alias);
+		nmatches=pcre_exec(alias->Re,NULL,url,url_len,0,0,ovector,sizeof(ovector)/sizeof(ovector[0]));
+		if (nmatches>=0) {
+			if (nmatches==0) nmatches=(int)(sizeof(ovector)/sizeof(ovector[0]))/3*2; //only 2/3 of the vector is used by pcre_exec
+			if (nmatches==1 || !alias->SubPartern) { //no subpattern to replace
+				*url_ptr=alias->Alias;
+			} else {
+				repl_idx=0;
+				str=alias->Alias;
+				for (i=0 ; str[i] ; i++) {
+					// both the sed \1 and the perl $1 replacement operators are accepted
+					if ((str[i]=='\\' || str[i]=='$') && isdigit(str[i+1])) {
+						sub=str[++i]-'0';
+						if (sub>=1 && sub<=nmatches) {
+							/*
+							 * ovector[sub] is the start position of the match.
+							 * ovector[sub+1] is the end position of the match.
+							 */
+							sub<<=1;
+							if (repl_idx+ovector[sub+1]-ovector[sub]>=sizeof(Replacement)-1) break;
+							memcpy(Replacement+repl_idx,url+ovector[sub],ovector[sub+1]-ovector[sub]);
+							repl_idx+=ovector[sub+1]-ovector[sub];
+							continue;
+						}
+					}
+					if (repl_idx>=sizeof(Replacement)-1) break;
+					Replacement[repl_idx++]=str[i];
+				}
+				Replacement[repl_idx]='\0';
+				*url_ptr=Replacement;
+			}
+			return(true);
 		}
 	}
-	return(url);
+	return(false);
 }
 #endif
 
@@ -807,7 +862,6 @@ const char *process_url(char *url,bool full_url)
 	char *str;
 	const char *start;
 	int type;
-	const char *address;
 	unsigned char ipv4[4];
 	unsigned short int ipv6[8];
 	const char *next;
@@ -818,11 +872,10 @@ const char *process_url(char *url,bool full_url)
 		*str='\0';
 #ifdef USE_PCRE
 		if (FirstAliasRe) {
-			address=alias_url_regex(start);
-			if (address!=start) return(address);
+			if (alias_url_regex(&start)) return(start);
 		}
 #endif
-		type=extract_address_mask(start,&address,ipv4,ipv6,NULL,&next);
+		type=extract_address_mask(start,NULL,ipv4,ipv6,NULL,&next);
 		if (type==1) {
 			if (FirstAliasName)
 				start=alias_url_name(start,next);
diff --git a/util.c b/util.c
index 32f076c..1891b75 100644
--- a/util.c
+++ b/util.c
@@ -1857,6 +1857,7 @@ void unlinkdir(const char *dir,int contentonly)
 
   \param buf The buffer to parse.
   \param text A pointer to set to the beginning of the string pattern. No terminating zero is inserted.
+              The pointer may be NULL.
   \param ipv4 A 4 bytes buffer to store the bytes of the IPv4 address.
   \param ipv6 A 8 short integers buffer to store the values of the IPv6 address.
   \param nbits The number of prefix bits for an IP address.
@@ -1948,8 +1949,10 @@ int extract_address_mask(const char *buf,const char **text,unsigned char *ipv4,u
 			addr[addr_len++]=(unsigned short)(value6 & 0xFFFFU);
 	}
 	if (!ip_size) {
-		*text=buf;
-		if (bracket) (*text)--;
+		if (text) {
+			*text=buf;
+			if (bracket) (*text)--;
+		}
 		while ((unsigned char)buf[i]>' ') i++;
 		if (next) *next=buf+i;
 		return(1);