From: Willy Tarreau <w@1wt.eu>
Date: Thu, 2 Sep 2021 17:46:08 +0000 (+0200)
Subject: BUG/MINOR: vars: properly set the argument parsing context in the expression
X-Git-Tag: v2.5-dev6~14
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=54b96d99556a27e15ee77b8b498d011cda2771e9;p=thirdparty%2Fhaproxy.git

BUG/MINOR: vars: properly set the argument parsing context in the expression

When the expression called in "set-var" uses argments that require late
resolution, the context must be set. At the moment, any unknown argument
is misleadingly reported as "ACL":

    frontend f
        bind :8080
        mode http
        http-request set-var(proc.a) be_conn(foo)

   parsing [b1.cfg:4]: unable to find backend 'foo' referenced in arg 1 \
   of ACL keyword 'be_conn' in proxy 'f'.

Once the context is properly set, it now says the truth:

   parsing [b1.cfg:8]: unable to find backend 'foo' referenced in arg 1 \
   of sample fetch keyword 'be_conn' in http-request expression in proxy 'f'.

This may be backported but is not really important. If so, the preceeding
patches "BUG/MINOR: vars: improve accuracy of the rules used to check
expression validity" and "MINOR: sample: add missing ARGC_ entries" must
be backported as well.
---

diff --git a/src/vars.c b/src/vars.c
index 6fa894b9a2..156eb943cb 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -774,35 +774,38 @@ static enum act_parse_ret parse_store(const char **args, int *arg, struct proxy
 
 	kw_name = args[*arg-1];
 
-	rule->arg.vars.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
-	                                        px->conf.args.line, err, &px->conf.args, NULL);
-	if (!rule->arg.vars.expr)
-		return ACT_RET_PRS_ERR;
-
 	switch (rule->from) {
 	case ACT_F_TCP_REQ_SES:
 		flags = SMP_VAL_FE_SES_ACC;
+		px->conf.args.ctx = ARGC_TSE;
 		break;
 	case ACT_F_TCP_REQ_CNT:
 		flags = (px->cap & PR_CAP_FE) ? SMP_VAL_FE_REQ_CNT : SMP_VAL_BE_REQ_CNT;
+		px->conf.args.ctx = ARGC_TRQ;
 		break;
 	case ACT_F_TCP_RES_CNT:
 		flags = (px->cap & PR_CAP_FE) ? SMP_VAL_FE_RES_CNT : SMP_VAL_BE_RES_CNT;
+		px->conf.args.ctx = ARGC_TRS;
 		break;
 	case ACT_F_HTTP_REQ:
 		flags = (px->cap & PR_CAP_FE) ? SMP_VAL_FE_HRQ_HDR : SMP_VAL_BE_HRQ_HDR;
+		px->conf.args.ctx = ARGC_HRQ;
 		break;
 	case ACT_F_HTTP_RES:
 		flags = (px->cap & PR_CAP_BE) ? SMP_VAL_BE_HRS_HDR : SMP_VAL_FE_HRS_HDR;
+		px->conf.args.ctx =  ARGC_HRS;
 		break;
 	case ACT_F_TCP_CHK:
 		flags = SMP_VAL_BE_CHK_RUL;
+		px->conf.args.ctx = ARGC_TCK;
 		break;
 	case ACT_F_CFG_PARSER:
 		flags = SMP_VAL_CFG_PARSER;
+		px->conf.args.ctx = ARGC_CFG;
 		break;
 	case ACT_F_CLI_PARSER:
 		flags = SMP_VAL_CLI_PARSER;
+		px->conf.args.ctx = ARGC_CLI;
 		break;
 	default:
 		memprintf(err,
@@ -810,6 +813,12 @@ static enum act_parse_ret parse_store(const char **args, int *arg, struct proxy
 			  rule->from);
 		return ACT_RET_PRS_ERR;
 	}
+
+	rule->arg.vars.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
+	                                        px->conf.args.line, err, &px->conf.args, NULL);
+	if (!rule->arg.vars.expr)
+		return ACT_RET_PRS_ERR;
+
 	if (!(rule->arg.vars.expr->fetch->val & flags)) {
 		memprintf(err,
 			  "fetch method '%s' extracts information from '%s', none of which is available here",