net: Move NetClientState.info_str to dynamic allocations

The info_str field of the NetClientState structure is static and has a size
of 256 bytes. This amount is often unclaimed, and the field itself is used
exclusively for HMP "info network".

The patch translates info_str to dynamic memory allocation.

This action is also allows us to painlessly discard usage of this field
for backend devices.

Signed-off-by: Alexey Kirillov <lekiravi@yandex-team.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 5 insertions, 8 deletions

diff --git a/net/tap.c b/net/tap.c
index 8041245ba7..f864f434b2 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -625,8 +625,7 @@ int net_init_bridge(const Netdev *netdev, const char *name,
         stored->helper = g_strdup(helper);
     }
 
-    snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
-             br);
+    s->nc.info_str = g_strdup_printf("helper=%s,br=%s", helper, br);
 
     return 0;
 }
@@ -714,7 +713,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
             g_free(tmp_s);
         }
 
-        snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
+        s->nc.info_str = g_strdup_printf("fd=%d", fd);
     } else if (tap->has_helper) {
         if (!stored->has_helper) {
             stored->has_helper = true;
@@ -727,8 +726,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                                        g_strdup(DEFAULT_BRIDGE_INTERFACE);
         }
 
-        snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
-                 tap->helper);
+        s->nc.info_str = g_strdup_printf("helper=%s", tap->helper);
     } else {
         if (ifname && !stored->has_ifname) {
             stored->has_ifname = true;
@@ -745,9 +743,8 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
             stored->downscript = g_strdup(downscript);
         }
 
-        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
-                 "ifname=%s,script=%s,downscript=%s", ifname, script,
-                 downscript);
+        s->nc.info_str = g_strdup_printf("ifname=%s,script=%s,downscript=%s",
+                                         ifname, script, downscript);
 
         if (strcmp(downscript, "no") != 0) {
             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);