iscsi-scstd: Keep portal tokenizer state local

Use a separate strtok_r saveptr for each listen-address, internal-portal
validation and portal-match operation. Preserve delimiters, limits and
buffer ownership. No tokenizer race was reproduced; this change makes
the parser state explicit and local to each operation.

Cppcheck reports strtokCalled at these tokenization sites:
  Non reentrant function 'strtok' called. For threadsafe applications
  it is recommended to use the reentrant replacement function 'strtok_r'.

iscsi-scst/usr/event.c

@@ -1131,7 +1131,7 @@ static int handle_e_set_attr_value(int fd, const struct iscsi_kern_event *event)
 			/* We have been provided with a string, check the contents. */
 			if (strchr(p, ' ')) {
 				char *portals = strdup(p);
-				char *portal;
+				char *portal, *saveptr;
 
 				if (!portals) {
 					log_error("Memory error (internal_portal)");
@@ -1139,7 +1139,7 @@ static int handle_e_set_attr_value(int fd, const struct iscsi_kern_event *event)
 					goto out_free;
 				}
 
-				portal = strtok(portals, " ");
+				portal = strtok_r(portals, " ", &saveptr);
 				while (portal != NULL) {
 					if (!is_addr(portal)) {
 						log_error("Invalid address supplied %s", portal);
@@ -1147,7 +1147,7 @@ static int handle_e_set_attr_value(int fd, const struct iscsi_kern_event *event)
 						res = -EINVAL;
 						goto out_free;
 					}
-					portal = strtok(NULL, " ");
+					portal = strtok_r(NULL, " ", &saveptr);
 				}
 				free(portals);
 			} else {

iscsi-scst/usr/iscsi_scstd.c

@@ -910,7 +910,7 @@ int main(int argc, char **argv)
 			gid = strtoul(optarg, NULL, 0);
 			break;
 		case 'a': {
-			char *server_address, *token;
+			char *server_address, *token, *saveptr;
 			int i = 0;
 
 			server_address = strdup(optarg);
@@ -919,14 +919,14 @@ int main(int argc, char **argv)
 				exit(-1);
 			}
 
-			token = strtok(server_address, " ");
+			token = strtok_r(server_address, " ", &saveptr);
 
 			while ((i < ADDR_MAX) && token) {
 				log_debug(0, "Address to listen: %s\n", token);
 				server_addresses[i] = token;
 
 				i++;
-				token = strtok(NULL, " ");
+				token = strtok_r(NULL, " ", &saveptr);
 			}
 
 			break;

iscsi-scst/usr/iscsid.c

@@ -1029,14 +1029,15 @@ static bool on_internal_portal(struct connection *conn)
 		char *portals = strdup(internal_portal);
 
 		if (portals) {
-			char *portal = strtok(portals, " ");
+			char *saveptr;
+			char *portal = strtok_r(portals, " ", &saveptr);
 
 			while (portal != NULL) {
 				if (!strcmp(portal, conn->target_portal)) {
 					free(portals);
 					return true;
 				}
-				portal = strtok(NULL, " ");
+				portal = strtok_r(NULL, " ", &saveptr);
 			}
 			free(portals);
 		}