From 831734cce6494032e9233caff4d8442b3a1e7fef Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 25 Nov 2020 11:02:20 +0100 Subject: [PATCH] net: Fix handling of id in netdev_add and netdev_del CLI -netdev accumulates in option group "netdev". Before commit 08712fcb85 "net: Track netdevs in NetClientState rather than QemuOpt", netdev_add added to the option group, and netdev_del removed from it, both HMP and QMP. Thus, every netdev had a corresponding QemuOpts in this option group. Commit 08712fcb85 dropped this for QMP netdev_add and both netdev_del. Now a netdev has a corresponding QemuOpts only when it was created with CLI or HMP. Two issues: * QMP and HMP netdev_del can leave QemuOpts behind, breaking HMP netdev_add. Reproducer: $ qemu-system-x86_64 -S -display none -nodefaults -monitor stdio QEMU 5.1.92 monitor - type 'help' for more information (qemu) netdev_add user,id=net0 (qemu) info network net0: index=0,type=user,net=10.0.2.0,restrict=off (qemu) netdev_del net0 (qemu) info network (qemu) netdev_add user,id=net0 upstream-qemu: Duplicate ID 'net0' for netdev Try "help netdev_add" for more information Fix by restoring the QemuOpts deletion in qmp_netdev_del(), but with a guard, because the QemuOpts need not exist. * QMP netdev_add loses its "no duplicate ID" check. Reproducer: $ qemu-system-x86_64 -S -display none -qmp stdio {"QMP": {"version": {"qemu": {"micro": 92, "minor": 1, "major": 5}, "package": "v5.2.0-rc2-1-g02c1f0142c"}, "capabilities": ["oob"]}} {"execute": "qmp_capabilities"} {"return": {}} {"execute": "netdev_add", "arguments": {"type": "user", "id":"net0"}} {"return": {}} {"execute": "netdev_add", "arguments": {"type": "user", "id":"net0"}} {"return": {}} Fix by adding a duplicate ID check to net_client_init1() to replace the lost one. The check is redundant for callers where QemuOpts still checks, i.e. for CLI and HMP. Reported-by: Andrew Melnichenko Fixes: 08712fcb851034228b61f75bd922863a984a4f60 Cc: qemu-stable@nongnu.org Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Signed-off-by: Jason Wang --- net/net.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/net/net.c b/net/net.c index e1035f21d1..c1cd9c75f6 100644 --- a/net/net.c +++ b/net/net.c @@ -983,6 +983,7 @@ static int (* const net_client_init_fun[NET_CLIENT_DRIVER__MAX])( static int net_client_init1(const Netdev *netdev, bool is_netdev, Error **errp) { NetClientState *peer = NULL; + NetClientState *nc; if (is_netdev) { if (netdev->type == NET_CLIENT_DRIVER_NIC || @@ -1010,6 +1011,12 @@ static int net_client_init1(const Netdev *netdev, bool is_netdev, Error **errp) } } + nc = qemu_find_netdev(netdev->id); + if (nc) { + error_setg(errp, "Duplicate ID '%s'", netdev->id); + return -1; + } + if (net_client_init_fun[netdev->type](netdev, netdev->id, peer, errp) < 0) { /* FIXME drop when all init functions store an Error */ if (errp && !*errp) { @@ -1020,8 +1027,6 @@ static int net_client_init1(const Netdev *netdev, bool is_netdev, Error **errp) } if (is_netdev) { - NetClientState *nc; - nc = qemu_find_netdev(netdev->id); assert(nc); nc->is_netdev = true; @@ -1135,6 +1140,7 @@ void qmp_netdev_add(Netdev *netdev, Error **errp) void qmp_netdev_del(const char *id, Error **errp) { NetClientState *nc; + QemuOpts *opts; nc = qemu_find_netdev(id); if (!nc) { @@ -1149,6 +1155,16 @@ void qmp_netdev_del(const char *id, Error **errp) } qemu_del_net_client(nc); + + /* + * Wart: we need to delete the QemuOpts associated with netdevs + * created via CLI or HMP, to avoid bogus "Duplicate ID" errors in + * HMP netdev_add. + */ + opts = qemu_opts_find(qemu_find_opts("netdev"), id); + if (opts) { + qemu_opts_del(opts); + } } static void netfilter_print_info(Monitor *mon, NetFilterState *nf)