MINOR: arg: add an argument type for identifier

The ARGT_ID argument type may now be used to set a custom resolve
function in order to help resolve the argument string value. If the
custom resolve function is not set, the behavior is the same as of
type ARGT_STR.

Author: ddosen

include/haproxy/arg-t.h

@@ -46,6 +46,7 @@ enum {
 	ARGT_STOP = 0, /* end of the arg list */
 	ARGT_SINT,     /* signed 64 bit integer. */
 	ARGT_STR,      /* string */
+	ARGT_ID,       /* identifier */
 	ARGT_IPV4,     /* an IPv4 address */
 	ARGT_MSK4,     /* an IPv4 address mask (integer or dotted), stored as ARGT_IPV4 */
 	ARGT_IPV6,     /* an IPv6 address */
@@ -124,6 +125,12 @@ struct arg {
 	unsigned char unresolved; /* argument contains a string in <str> that must be resolved and freed */
 	unsigned char type_flags; /* type-specific extra flags (eg: case sensitivity for regex), ARGF_* */
 	union arg_data data;      /* argument data */
+
+	int (*resolve_ptr)(struct arg *arg, char **err); /* ptr to custom resolve function that can be used
+	                                                  * for the arg of type ARGT_ID; the err must always
+	                                                  * be compatible with free() (i.e. either null or
+	                                                  * the result of a malloc/strdup/memprintf call)
+	                                                  */
 };
 
 /* arg lists are used to store information about arguments that could not be

src/arg.c

@@ -24,6 +24,7 @@ const char *arg_type_names[ARGT_NBTYPES] = {
 	[ARGT_STOP] = "end of arguments",
 	[ARGT_SINT] = "integer",
 	[ARGT_STR]  = "string",
+	[ARGT_ID]   = "identifier",
 	[ARGT_IPV4] = "IPv4 address",
 	[ARGT_MSK4] = "IPv4 mask",
 	[ARGT_IPV6] = "IPv6 address",
@@ -237,6 +238,7 @@ int make_arg_list(const char *in, int len, uint64_t mask, struct arg **argp,
 			arg->type = ARGT_SINT;
 			break;
 
+		case ARGT_ID:
 		case ARGT_FE:
 		case ARGT_BE:
 		case ARGT_TAB:

src/sample.c

@@ -1444,6 +1444,20 @@ int smp_resolve_args(struct proxy *p, char **err)
 		pname = p->id;
 
 		switch (arg->type) {
+		case ARGT_ID:
+			err2 = NULL;
+
+			if (arg->resolve_ptr && !arg->resolve_ptr(arg, &err2)) {
+				memprintf(err, "%sparsing [%s:%d]: error in identifier '%s' in arg %d of %s%s%s%s '%s' %s proxy '%s' : %s.\n",
+					  *err ? *err : "", cur->file, cur->line,
+					 arg->data.str.area,
+					 cur->arg_pos + 1, conv_pre, conv_ctx, conv_pos, ctx, cur->kw, where, p->id, err2);
+				ha_free(&err2);
+				cfgerr++;
+				continue;
+			}
+			break;
+
 		case ARGT_SRV:
 			if (!arg->data.str.data) {
 				memprintf(err, "%sparsing [%s:%d]: missing server name in arg %d of %s%s%s%s '%s' %s proxy '%s'.\n",