From: Jerome Magnin <jmagnin@haproxy.com>
Date: Sun, 16 Feb 2020 18:20:19 +0000 (+0100)
Subject: MINOR: sample: regsub now supports backreferences
X-Git-Tag: v2.2-dev3~61
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07e1e3c93e;p=thirdparty%2Fhaproxy.git

MINOR: sample: regsub now supports backreferences

Now that the configuration parser is more flexible with samples,
converters and their arguments, we can leverage this to enable
support for backreferences in regsub.
---

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 392742eea3..306d6396a6 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -14161,6 +14161,11 @@ regsub(<regex>,<subst>[,<flags>])
      # copy query string to x-query and drop all leading '?', ';' and '&'
      http-request set-header x-query "%[query,regsub([?;&]*,'')]"
 
+     # capture groups and backreferences
+     # both lines do the same.
+     http-request redirect location %[url,'regsub("(foo|bar)([0-9]+)?","\2\1",i)]'
+     http-request redirect location %[url,regsub(\"(foo|bar)([0-9]+)?\",\"\2\1\",i)]
+
 capture-req(<id>)
   Capture the string entry in the request slot <id> and returns the entry as
   is. If the slot doesn't exist, the capture fails silently.
diff --git a/src/sample.c b/src/sample.c
index ef0f7b00cb..24d21100e0 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -2354,6 +2354,7 @@ static int sample_conv_regsub(const struct arg *arg_p, struct sample *smp, void
 	struct my_regex *reg = arg_p[0].data.reg;
 	regmatch_t pmatch[MAX_MATCH];
 	struct buffer *trash = get_trash_chunk();
+	struct buffer *output;
 	int flag, max;
 	int found;
 
@@ -2386,16 +2387,21 @@ static int sample_conv_regsub(const struct arg *arg_p, struct sample *smp, void
 		if (!found)
 			break;
 
+		output = alloc_trash_chunk();
+		output->data = exp_replace(output->area, output->size, start, arg_p[1].data.str.area, pmatch);
+
 		/* replace the matching part */
-		max = trash->size - trash->data;
+		max = output->size - output->data;
 		if (max) {
-			if (max > arg_p[1].data.str.data)
-				max = arg_p[1].data.str.data;
+			if (max > output->data)
+				max = output->data;
 			memcpy(trash->area + trash->data,
-			       arg_p[1].data.str.area, max);
+			       output->area, max);
 			trash->data += max;
 		}
 
+		free_trash_chunk(output);
+
 		/* stop here if we're done with this string */
 		if (start >= end)
 			break;