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Knut Omang 9cf961bba7 sockets: Handle race condition between binds to the same port
If an offset of ports is specified to the inet_listen_saddr function(),
and two or more processes tries to bind from these ports at the same time,
occasionally more than one process may be able to bind to the same
port. The condition is detected by listen() but too late to avoid a failure.

This function is called by socket_listen() and used
by all socket listening code in QEMU, so all cases where any form of dynamic
port selection is used should be subject to this issue.

Add code to close and re-establish the socket when this
condition is observed, hiding the race condition from the user.

Also clean up some issues with error handling to allow more
accurate reporting of the cause of an error.

This has been developed and tested by means of the
test-listen unit test in the previous commit.
Enable the test for make check now that it passes.

Reviewed-by: Bhavesh Davda <bhavesh.davda@oracle.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Girish Moodalbail <girish.moodalbail@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-10-16 16:55:31 +01:00
accel exec-all: extract tb->tc_* into a separate struct tc_tb 2017-10-10 07:37:10 -07:00
audio buildsys: Move audio libs to per object 2017-09-22 10:20:34 +08:00
backends tpm-backend: Move realloc_buffer() implementation to tpm-tis model 2017-10-13 07:34:33 -04:00
block nbd patches for 2017-10-14 2017-10-16 15:54:42 +01:00
bsd-user cpu: make cpu_generic_init() abort QEMU on error 2017-09-19 09:09:32 -03:00
chardev chardev/baum: fix baum that releases brlapi twice 2017-09-26 09:11:22 +03:00
contrib libvhost-user: Support VHOST_USER_SET_SLAVE_REQ_FD 2017-10-12 16:57:50 +02:00
crypto block: convert qcrypto_block_encrypt|decrypt to take bytes offset 2017-10-06 16:30:47 +02:00
default-configs msf2: Add Smartfusion2 SoC 2017-09-21 16:36:56 +01:00
disas
docs specs: Describe the TPM support in QEMU 2017-10-13 07:34:33 -04:00
dtc@558cd81bdd
fpu
fsdev
gdb-xml
hw tpm: Added support for TPM emulator 2017-10-13 07:34:33 -04:00
include nbd patches for 2017-10-14 2017-10-16 15:54:42 +01:00
io io: add trace events for websockets frame handling 2017-10-04 13:21:53 +01:00
libdecnumber
linux-headers linux-headers: sync against v4.14-rc1 2017-09-29 10:58:31 +02:00
linux-user cpu: make cpu_generic_init() abort QEMU on error 2017-09-19 09:09:32 -03:00
migration dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes 2017-10-06 16:28:58 +02:00
nbd nbd: header constants indenting 2017-10-13 09:27:38 -05:00
net slirp: Add explanation for hostfwd parsing failure 2017-09-24 20:04:09 +02:00
pc-bios s390: set DHCP client architecure id for netboot 2017-09-19 18:21:33 +02:00
po
qapi tpm: Added support for TPM emulator 2017-10-13 07:34:33 -04:00
qga Convert single line fprintf(.../n) to warn_report() 2017-09-19 14:09:34 +02:00
qobject
qom qom/cpu: move cpu_model null check to cpu_class_by_name() 2017-10-09 23:21:52 -03:00
replay migration: pre_save return int 2017-09-27 11:35:59 +01:00
roms
scripts scripts: Remove debug parameter from QEMUMachine 2017-10-11 15:15:17 -03:00
scsi scsi: add persistent reservation manager using qemu-pr-helper 2017-09-22 21:07:27 +02:00
slirp migration: pre_save return int 2017-09-27 11:35:59 +01:00
stubs
target target/arm: Implement SG instruction corner cases 2017-10-12 13:23:14 +01:00
tcg tcg/mips: delete commented out extern keyword. 2017-10-10 09:45:01 -07:00
tests nbd patches for 2017-10-14 2017-10-16 15:54:42 +01:00
trace Convert single line fprintf(.../n) to warn_report() 2017-09-19 14:09:34 +02:00
ui ui: Always remove an old VNC channel watch before adding a new one 2017-10-04 13:21:53 +01:00
util sockets: Handle race condition between binds to the same port 2017-10-16 16:55:31 +01:00
.dir-locals.el
.editorconfig
.exrc
.gdbinit
.gitignore scsi: Ignore executable for in-tree builds 2017-09-29 10:56:56 +02:00
.gitmodules
.mailmap
.shippable.yml
.travis.yml
arch_init.c
balloon.c
block.c commit: Remove overlay_bs 2017-10-06 16:28:58 +02:00
blockdev-nbd.c
blockdev.c
blockjob.c
bootdevice.c
bt-host.c
bt-vhci.c
Changelog
CODING_STYLE
configure tpm: Added support for TPM emulator 2017-10-13 07:34:33 -04:00
COPYING
COPYING.LIB
COPYING.PYTHON
cpus-common.c
cpus.c memory: Get rid of address_space_init_shareable 2017-09-22 01:06:51 +02:00
device_tree.c
device-hotplug.c
disas.c
dma-helpers.c
dump.c exec,dump,i386,ppc,s390x: don't include exec/cpu-all.h explicitly 2017-09-19 18:21:33 +02:00
exec.c util: move qemu_real_host_page_size/mask to osdep.h 2017-10-10 09:45:00 -07:00
gdbstub.c
HACKING
hmp-commands-info.hx hmp-commands-info: Change "@findex FOO" to "@findex info FOO" 2017-10-05 10:08:39 +01:00
hmp-commands.hx
hmp.c tpm: Added support for TPM emulator 2017-10-13 07:34:33 -04:00
hmp.h
ioport.c
iothread.c iothread: delay the context release to finalize 2017-10-03 14:36:19 -04:00
LICENSE
MAINTAINERS MAINTAINERS: use KVM s390x maintainers for kvm-stubs.c and kvm_s390x.h 2017-10-06 10:53:02 +02:00
Makefile build-sys: make vhost-user-scsi depend on libvhost-user.a 2017-10-10 23:31:08 +02:00
Makefile.objs build-sys: make vhost-user-scsi depend on libvhost-user.a 2017-10-10 23:31:08 +02:00
Makefile.target accel/hax: move hax-stub.c to accel/stubs/ 2017-09-19 16:20:49 +02:00
memory_ldst.inc.c
memory_mapping.c
memory.c memory: Share special empty FlatView 2017-09-22 01:06:51 +02:00
module-common.c
monitor.c hmp: Fix unknown command for subtable 2017-10-05 10:01:21 +01:00
numa.c NUMA: Replace MAX_NODES with nb_numa_nodes in for loop 2017-09-19 16:51:33 -03:00
os-posix.c
os-win32.c
qapi-schema.json watchdog: Allow setting action on the fly 2017-10-02 13:09:09 +02:00
qdev-monitor.c
qdict-test-data.txt
qemu-bridge-helper.c
qemu-doc.texi qemu-options: Deprecate -nodefconfig 2017-10-09 23:21:52 -03:00
qemu-ga.texi
qemu-img-cmds.hx qemu-img: add --shrink flag for resize 2017-09-26 15:00:32 +02:00
qemu-img.c qemu-img: add --shrink flag for resize 2017-09-26 15:00:32 +02:00
qemu-img.texi qemu-img: add --shrink flag for resize 2017-09-26 15:00:32 +02:00
qemu-io-cmds.c qemu-io: Drop write permissions before read-only reopen 2017-09-26 14:46:23 +02:00
qemu-io.c qemu-io: Add -C for opening with copy-on-read 2017-10-06 16:28:58 +02:00
qemu-nbd.c
qemu-nbd.texi
qemu-option-trace.texi
qemu-options-wrapper.h
qemu-options.h
qemu-options.hx tpm: Added support for TPM emulator 2017-10-13 07:34:33 -04:00
qemu-seccomp.c
qemu-tech.texi
qemu.nsi
qemu.sasl
qmp.c
qtest.c
README
replication.c
replication.h
rules.mak
thunk.c
tpm.c tpm: Move tpm_cleanup() to right place 2017-10-13 07:34:33 -04:00
trace-events memory: trace FlatView creation and destruction 2017-09-22 01:06:51 +02:00
VERSION
version.rc
vl.c tpm: Move tpm_cleanup() to right place 2017-10-13 07:34:33 -04:00

         QEMU README
         ===========

QEMU is a generic and open source machine & userspace emulator and
virtualizer.

QEMU is capable of emulating a complete machine in software without any
need for hardware virtualization support. By using dynamic translation,
it achieves very good performance. QEMU can also integrate with the Xen
and KVM hypervisors to provide emulated hardware while allowing the
hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
near native performance for CPUs. When QEMU emulates CPUs directly it is
capable of running operating systems made for one machine (e.g. an ARMv7
board) on a different machine (e.g. an x86_64 PC board).

QEMU is also capable of providing userspace API virtualization for Linux
and BSD kernel interfaces. This allows binaries compiled against one
architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
different architecture ABI (e.g. the Linux x86_64 ABI). This does not
involve any hardware emulation, simply CPU and syscall emulation.

QEMU aims to fit into a variety of use cases. It can be invoked directly
by users wishing to have full control over its behaviour and settings.
It also aims to facilitate integration into higher level management
layers, by providing a stable command line interface and monitor API.
It is commonly invoked indirectly via the libvirt library when using
open source applications such as oVirt, OpenStack and virt-manager.

QEMU as a whole is released under the GNU General Public License,
version 2. For full licensing details, consult the LICENSE file.


Building
========

QEMU is multi-platform software intended to be buildable on all modern
Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
of other UNIX targets. The simple steps to build QEMU are:

  mkdir build
  cd build
  ../configure
  make

Additional information can also be found online via the QEMU website:

  http://qemu-project.org/Hosts/Linux
  http://qemu-project.org/Hosts/Mac
  http://qemu-project.org/Hosts/W32


Submitting patches
==================

The QEMU source code is maintained under the GIT version control system.

   git clone git://git.qemu-project.org/qemu.git

When submitting patches, the preferred approach is to use 'git
format-patch' and/or 'git send-email' to format & send the mail to the
qemu-devel@nongnu.org mailing list. All patches submitted must contain
a 'Signed-off-by' line from the author. Patches should follow the
guidelines set out in the HACKING and CODING_STYLE files.

Additional information on submitting patches can be found online via
the QEMU website

  http://qemu-project.org/Contribute/SubmitAPatch
  http://qemu-project.org/Contribute/TrivialPatches


Bug reporting
=============

The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:

  https://bugs.launchpad.net/qemu/

If using QEMU via an operating system vendor pre-built binary package, it
is preferable to report bugs to the vendor's own bug tracker first. If
the bug is also known to affect latest upstream code, it can also be
reported via launchpad.

For additional information on bug reporting consult:

  http://qemu-project.org/Contribute/ReportABug


Contact
=======

The QEMU community can be contacted in a number of ways, with the two
main methods being email and IRC

 - qemu-devel@nongnu.org
   http://lists.nongnu.org/mailman/listinfo/qemu-devel
 - #qemu on irc.oftc.net

Information on additional methods of contacting the community can be
found online via the QEMU website:

  http://qemu-project.org/Contribute/StartHere

-- End