[MINOR] proxy: provide function to retrieve backend/server pointers

int get_backend_server(const char *bk_name, const char *sv_name,
                       struct proxy **bk, struct server **sv);

This function scans the list of backends and servers to retrieve the first
backend and the first server with the given names, and sets them in both
parameters. It returns zero if either is not found, or non-zero and sets
the ones it did not found to NULL. If a NULL pointer is passed for the
backend, only the pointer to the server will be updated.

include/proto/proxy.h

@@ -42,6 +42,8 @@ const char *proxy_mode_str(int mode);
 struct proxy *findproxy(const char *name, int mode, int cap);
 struct server *findserver(const struct proxy *px, const char *name);
 int proxy_cfg_ensure_no_http(struct proxy *curproxy);
+int get_backend_server(const char *bk_name, const char *sv_name,
+		       struct proxy **bk, struct server **sv);
 
 /*
  * This function returns a string containing the type of the proxy in a format

src/proxy.c

@@ -76,6 +76,38 @@ const char *proxy_mode_str(int mode) {
 		return "unknown";
 }
 
+/*
+ * This function scans the list of backends and servers to retrieve the first
+ * backend and the first server with the given names, and sets them in both
+ * parameters. It returns zero if either is not found, or non-zero and sets
+ * the ones it did not found to NULL. If a NULL pointer is passed for the
+ * backend, only the pointer to the server will be updated.
+ */
+int get_backend_server(const char *bk_name, const char *sv_name,
+		       struct proxy **bk, struct server **sv)
+{
+	struct proxy *p;
+	struct server *s;
+
+	*sv = NULL;
+
+	for (p = proxy; p; p = p->next)
+		if ((p->cap & PR_CAP_BE) && (strcmp(p->id, bk_name) == 0))
+			break;
+	if (bk)
+		*bk = p;
+	if (!p)
+		return 0;
+
+	for (s = p->srv; s; s = s->next)
+		if (strcmp(s->id, sv_name) == 0)
+			break;
+	*sv = s;
+	if (!s)
+		return 0;
+	return 1;
+}
+
 /* This function parses a "timeout" statement in a proxy section. It returns
  * -1 if there is any error, 1 for a warning, otherwise zero. If it does not
  * return zero, it may write an error message into the <err> buffer, for at