qemu/net
Laurent Vivier 894022e616 net: check if the file descriptor is valid before using it
qemu_set_nonblock() checks that the file descriptor can be used and, if
not, crashes QEMU. An assert() is used for that. The use of assert() is
used to detect programming error and the coredump will allow to debug
the problem.

But in the case of the tap device, this assert() can be triggered by
a misconfiguration by the user. At startup, it's not a real problem, but it
can also happen during the hot-plug of a new device, and here it's a
problem because we can crash a perfectly healthy system.

For instance:
 # ip link add link virbr0 name macvtap0 type macvtap mode bridge
 # ip link set macvtap0 up
 # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1)
 # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP
 (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9
 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0
 (qemu) device_del net0
 (qemu) netdev_del hostnet0
 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9
 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed.
 Aborted (core dumped)

To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the
problem without crashing.

In the same way, we also update the function for vhostfd in net_init_tap_one() and
for fd in net_init_socket() (both descriptors are provided by the user and can
be wrong).

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-15 21:00:13 +08:00
..
can qom: Drop parameter @errp of object_property_add() & friends 2020-05-15 07:07:58 +02:00
announce.c net/announce: Add optional ID 2019-07-02 10:21:06 +08:00
checksum.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
clients.h vhost-vdpa: introduce vhost-vdpa net client 2020-07-07 07:59:51 -04:00
colo-compare.c net/colo-compare.c: Expose compare "max_queue_size" to users 2020-07-15 21:00:13 +08:00
colo-compare.h colo-compare: use notifier to notify packets comparing result 2018-10-19 11:15:03 +08:00
colo.c net/colo-compare.c: Fix deadlock in compare_chr_send 2020-06-18 21:05:52 +08:00
colo.h net/colo-compare.c: Fix deadlock in compare_chr_send 2020-06-18 21:05:52 +08:00
dump.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
eth.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
filter-buffer.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
filter-mirror.c qom: Drop parameter @errp of object_property_add() & friends 2020-05-15 07:07:58 +02:00
filter-replay.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
filter-rewriter.c qom: Drop parameter @errp of object_property_add() & friends 2020-05-15 07:07:58 +02:00
filter.c qom: Put name parameter before value / visitor parameter 2020-07-10 15:18:08 +02:00
hub.c hw/net: Make NetCanReceive() return a boolean 2020-03-31 21:14:35 +08:00
hub.h net: Remove deprecated [hub_id name] tuple of 'hostfwd_add' / 'hostfwd_remove' 2020-03-09 18:44:04 +00:00
l2tpv3.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
Makefile.objs vhost-vdpa: introduce vhost-vdpa net client 2020-07-07 07:59:51 -04:00
net.c qom: Put name parameter before value / visitor parameter 2020-07-10 15:18:08 +02:00
netmap.c Include qemu/main-loop.h less 2019-08-16 13:31:52 +02:00
queue.c misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
slirp.c net: Remove deprecated [hub_id name] tuple of 'hostfwd_add' / 'hostfwd_remove' 2020-03-09 18:44:04 +00:00
socket.c net: check if the file descriptor is valid before using it 2020-07-15 21:00:13 +08:00
tap_int.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
tap-bsd.c Clean up inclusion of sysemu/sysemu.h 2019-08-16 13:31:53 +02:00
tap-linux.c Clean up inclusion of sysemu/sysemu.h 2019-08-16 13:31:53 +02:00
tap-linux.h Clean up decorations and whitespace around header guards 2016-07-12 16:20:46 +02:00
tap-solaris.c net/tap-solaris.c: Include qemu-common.h for TFR macro 2020-07-07 12:38:50 +02:00
tap-stub.c net/tap: Replace tap-haiku.c and tap-aix.c by a generic tap-stub.c 2017-05-23 10:10:38 +08:00
tap-win32.c Clean up inclusion of sysemu/sysemu.h 2019-08-16 13:31:53 +02:00
tap.c net: check if the file descriptor is valid before using it 2020-07-15 21:00:13 +08:00
trace-events colo-compare: Fix memory leak in packet_enqueue() 2020-06-18 21:05:52 +08:00
util.c net: Clean up includes 2016-02-04 17:41:30 +00:00
util.h net: do not depend on slirp internals 2019-01-14 00:44:29 +01:00
vde.c net/vde: print error on vde_open() failure 2018-03-26 14:52:43 +08:00
vhost-user-stub.c vhost-net-user: add stubs for when no virtio-net device is present 2019-02-21 12:28:01 -05:00
vhost-user.c chardev: Use QEMUChrEvent enum in IOEventHandler typedef 2020-01-08 11:15:35 +01:00
vhost-vdpa.c vhost-vdpa: introduce vhost-vdpa net client 2020-07-07 07:59:51 -04:00