ip6: fix memory leak when show ip6 router-advert fails

grout# show ip6 router-advert
error: command failed: Bad message
grout# ^D

==174902==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 328 byte(s) in 1 object(s) allocated from:
    #0 0x7fe0ca6c2250 in calloc (/lib64/libasan.so.8+0xc2250)
    #1 0x7fe0cadef910 in scols_new_table (/lib64/libsmartcols.so.1+0x6910)
    DPDK#2 0x417d0f in ra_show ../modules/ip6/cli/router_advert.c:19
    DPDK#3 0x41e836 in exec_strvec ../cli/exec.c:72
    DPDK#4 0x41e982 in exec_line ../cli/exec.c:106
    DPDK#5 0x41f412 in interact ../cli/interact.c:119
    DPDK#6 0x4216db in main ../cli/main.c:167
    ...
    DPDK#9 0x4017f4 in _start (/root/grout/build/grcli+0x4017f4)

Only allocate the table if the GR_IP6_IFACE_RA_SHOW api call is
successful.

Fixes: 8ed8b9d ("ip6: router advertisement configuration")
Signed-off-by: Robin Jarry <[email protected]>

Author: rjarry

modules/ip6/cli/router_advert.c

@@ -13,10 +13,7 @@
 #include <ecoli.h>
 #include <libsmartcols.h>
 
-#include <errno.h>
-
 static cmd_status_t ra_show(const struct gr_api_client *c, const struct ec_pnode *p) {
-	struct libscols_table *table = scols_new_table();
 	struct gr_ip6_ra_show_resp *resp;
 	struct gr_ip6_ra_show_req req;
 	struct gr_iface iface;
@@ -31,6 +28,7 @@ static cmd_status_t ra_show(const struct gr_api_client *c, const struct ec_pnode
 		return CMD_ERROR;
 	resp = resp_ptr;
 
+	struct libscols_table *table = scols_new_table();
 	scols_table_new_column(table, "IFACE", 0, 0);
 	scols_table_new_column(table, "RA", 0, 0);
 	scols_table_new_column(table, "interval", 0, 0);