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Eric Blake cf923b783e utils: Improve qemu_strtosz() to have 64 bits of precision
We have multiple clients of qemu_strtosz (qemu-io, the opts visitor,
the keyval visitor), and it gets annoying that edge-case testing is
impacted by implicit rounding to 53 bits of precision due to parsing
with strtod().  As an example posted by Rich Jones:
 $ nbdkit memory $(( 2**63 - 2**30 )) --run \
   'build/qemu-io -f raw "$uri" -c "w -P 3 $(( 2**63 - 2**30 - 512 )) 512" '
 write failed: Input/output error

because 9223372035781033472 got rounded to 0x7fffffffc0000000 which is
out of bounds.

It is also worth noting that our existing parser, by virtue of using
strtod(), accepts decimal AND hex numbers, even though test-cutils
previously lacked any coverage of the latter until the previous patch.
We do have existing clients that expect a hex parse to work (for
example, iotest 33 using qemu-io -c "write -P 0xa 0x200 0x400"), but
strtod() parses "08" as 8 rather than as an invalid octal number, so
we know there are no clients that depend on octal.  Our use of
strtod() also means that "0x1.8k" would actually parse as 1536 (the
fraction is 8/16), rather than 1843 (if the fraction were 8/10); but
as this was not covered in the testsuite, I have no qualms forbidding
hex fractions as invalid, so this patch declares that the use of
fractions is only supported with decimal input, and enhances the
testsuite to document that.

Our previous use of strtod() meant that -1 parsed as a negative; now
that we parse with strtoull(), negative values can wrap around modulo
2^64, so we have to explicitly check whether the user passed in a '-';
and make it consistent to also reject '-0'.  This has the minor effect
of treating negative values as EINVAL (with no change to endptr)
rather than ERANGE (with endptr advanced to what was parsed), visible
in the updated iotest output.

We also had no testsuite coverage of "1.1e0k", which happened to parse
under strtod() but is unlikely to occur in practice; as long as we are
making things more robust, it is easy enough to reject the use of
exponents in a strtod parse.

The fix is done by breaking the parse into an integer prefix (no loss
in precision), rejecting negative values (since we can no longer rely
on strtod() to do that), determining if a decimal or hexadecimal parse
was intended (with the new restriction that a fractional hex parse is
not allowed), and where appropriate, using a floating point fractional
parse (where we also scan to reject use of exponents in the fraction).
The bulk of the patch is then updates to the testsuite to match our
new precision, as well as adding new cases we reject (whether they
were rejected or inadvertently accepted before).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210211204438.1184395-3-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2021-03-08 13:36:12 -06:00
.github .github: point Repo Lockdown bot to GitLab repo 2021-02-09 20:53:56 +00:00
.gitlab-ci.d gitlab: add fine grained job deps for all build jobs 2021-02-19 06:29:05 +01:00
accel accel: kvm: Add aligment assert for kvm_log_clear_one_slot 2021-03-06 11:41:54 +01:00
audio
authz
backends hostmem: Don't report pmem attribute if unsupported 2021-02-18 18:34:47 -05:00
block qemu-config: add error propagation to qemu_config_parse 2021-03-06 11:41:54 +01:00
bsd-user exec: Use cpu_untagged_addr in g2h; split out g2h_untagged 2021-02-16 11:04:53 +00:00
capstone@f8b1b83301
chardev chardev: add nodelay option 2021-03-06 11:41:54 +01:00
contrib contrib: Open brace '{' following struct go on the same line 2021-02-18 08:17:27 +00:00
crypto crypto: Add spaces around operator 2021-01-29 17:07:53 +00:00
default-configs Hexagon build infrastructure 2021-02-18 08:25:06 -08:00
disas Hexagon (disas) disassembler 2021-02-18 07:48:22 -08:00
docs * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
dtc@85e5d83984
dump qapi: More complex uses of QAPI_LIST_APPEND 2021-01-28 08:08:45 +01:00
fpu
fsdev meson: Declare have_virtfs_proxy_helper in main meson.build 2021-01-23 15:55:04 -05:00
gdb-xml target/riscv: Remove built-in GDB XML files for CSRs 2021-01-16 10:57:21 -08:00
hw * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
include * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
io io: error_prepend() in qio_channel_readv_full_all() causes segfault 2021-02-12 07:50:59 -06:00
libdecnumber
linux-headers Update linux headers to 5.11-rc2 2021-01-21 11:19:45 +01:00
linux-user Hexagon (linux-user/hexagon) Linux user emulation 2021-02-18 07:48:22 -08:00
meson@776acd2a80
migration migration: dirty-bitmap: Allow control of bitmap persistence 2021-02-12 15:24:36 -06:00
monitor monitor/qmp: Stop processing requests when shutdown is requested 2021-02-15 15:10:14 +01:00
nbd nbd: server: Report holes for raw images 2021-03-08 13:08:45 -06:00
net Trivial patches 20210129 2021-01-29 10:10:43 +00:00
pc-bios roms/opensbi: Upgrade from v0.8 to v0.9 2021-03-04 09:43:29 -05:00
plugins accel/tcg: allow plugin instrumentation to be disable via cflags 2021-02-18 08:19:23 +00:00
po
python Python: close the log file kept by QEMUMachine before reading it 2021-02-15 21:40:16 -05:00
qapi qapi: Remove QMP events and commands from user-mode builds 2021-03-05 15:40:49 +01:00
qga * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
qobject qobject: braces {} are necessary for all arms of this statement 2021-02-04 13:20:29 +01:00
qom qom: Check for wellformed id in user_creatable_add_type() 2021-03-06 11:41:54 +01:00
replay replay: fix icount request when replaying clock access 2021-02-16 17:15:39 +01:00
roms roms/opensbi: Upgrade from v0.8 to v0.9 2021-03-04 09:43:29 -05:00
scripts qapi: Fix parse errors for removal of null from schema language 2021-03-05 15:40:50 +01:00
scsi scsi: inline sg_io_sense_from_errno() into the callers. 2021-03-06 11:42:56 +01:00
slirp@8f43a99191
softmmu trace: skip qemu_set_log_filename if no "-D" option was passed 2021-03-06 11:42:57 +01:00
storage-daemon qemu-storage-daemon: Enable object-add 2021-02-15 15:10:14 +01:00
stubs replay: fix icount request when replaying clock access 2021-02-16 17:15:39 +01:00
subprojects/libvhost-user build-sys: add libvhost-user missing dependencies 2021-01-23 09:26:41 -05:00
target * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
tcg tcg/tci: Remove TCG_CONST 2021-02-05 10:24:14 -10:00
tests utils: Improve qemu_strtosz() to have 64 bits of precision 2021-03-08 13:36:12 -06:00
tools virtiofs: drop remapped security.capability xattr as needed 2021-03-04 10:26:16 +00:00
trace trace: fix "-trace file=..." 2021-03-06 11:42:57 +01:00
ui ui/console: Pass placeholder surface to displays 2021-03-04 09:35:36 +01:00
util utils: Improve qemu_strtosz() to have 64 bits of precision 2021-03-08 13:36:12 -06:00
.cirrus.yml
.dir-locals.el
.editorconfig
.exrc
.gdbinit
.gitattributes maint: Tell git that *.py files should use python diff hunks 2021-02-15 22:13:34 -05:00
.gitignore Makefile: add GNU global tags support 2021-01-18 10:04:31 +00:00
.gitlab-ci.yml gitlab-ci.yml: Run check-tcg with TCI 2021-02-19 06:29:05 +01:00
.gitmodules gitmodules: use GitLab repos instead of qemu.org 2021-02-09 20:53:56 +00:00
.gitpublish
.mailmap
.patchew.yml
.readthedocs.yml
.travis.yml travis.yml: Limit simultaneous jobs to 3 2021-02-19 06:31:40 +01:00
block.c block: add bdrv_co_delete_file_noerr 2021-02-15 15:10:14 +01:00
blockdev-nbd.c qemu-nbd: Use SOMAXCONN for socket listen() backlog 2021-02-12 07:42:08 -06:00
blockdev.c block: use return status of bdrv_append() 2021-02-12 15:39:44 -06:00
blockjob.c blockjob: Fix crash with IOthread when block commit after snapshot 2021-02-15 15:10:14 +01:00
configure ui/console: message surface tweaks. 2021-03-04 12:58:50 +00:00
COPYING
COPYING.LIB
cpu.c accel/tcg: split TCG-only code from cpu_exec_realizefn 2021-02-05 10:24:14 -10:00
cpus-common.c
disas.c
exec-vary.c
gdbstub.c chardev: add nodelay option 2021-03-06 11:41:54 +01:00
gitdm.config
hmp-commands-info.hx
hmp-commands.hx hmp: remove "change vnc TARGET" command 2021-01-23 15:55:07 -05:00
iothread.c multi-process: define MPQemuMsg format and transmission functions 2021-02-10 09:23:28 +00:00
job-qmp.c qapi: Use QAPI_LIST_APPEND in trivial cases 2021-01-28 08:08:45 +01:00
job.c job: add .cancel handler for the driver 2021-02-12 11:23:19 -06:00
Kconfig
Kconfig.host multi-process: Add config option for multi-process QEMU 2021-02-09 20:53:56 +00:00
LICENSE
MAINTAINERS MAINTAINERS: add Vladimir as co-maintainer of NBD 2021-03-08 13:06:31 -06:00
Makefile build-sys: invoke ninja with -d keepdepfile 2021-03-06 11:42:57 +01:00
memory_ldst.c.inc fuzz: ignore address_space_map is_write flag 2021-02-08 14:43:54 +01:00
meson_options.txt multiprocess: move feature to meson_options.txt 2021-02-25 14:14:32 +01:00
meson.build * fix tracing vs -daemonize (Daniel) 2021-03-08 13:51:41 +00:00
module-common.c
os-posix.c os: deprecate the -enable-fips option and QEMU's FIPS enforcement 2021-01-29 17:07:53 +00:00
os-win32.c
qemu-bridge-helper.c
qemu-edid.c
qemu-img-cmds.hx
qemu-img.c qapi: Use QAPI_LIST_APPEND in trivial cases 2021-01-28 08:08:45 +01:00
qemu-io-cmds.c
qemu-io.c
qemu-keymap.c
qemu-nbd.c qemu-nbd: Permit --shared=0 for unlimited clients 2021-02-12 07:42:08 -06:00
qemu-options-wrapper.h
qemu-options.h
qemu-options.hx chardev: add nodelay option 2021-03-06 11:41:54 +01:00
qemu.nsi nsis: adjust for new MinGW paths 2021-01-23 15:55:05 -05:00
qemu.sasl
README.rst docs: move CODING_STYLE into the developer documentation 2021-02-24 11:05:21 +00:00
replication.c
replication.h
thunk.c
trace-events
VERSION
version.rc

===========
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:


.. code-block:: shell

  mkdir build
  cd build
  ../configure
  make

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

* `<https://qemu.org/Hosts/Linux>`_
* `<https://qemu.org/Hosts/Mac>`_
* `<https://qemu.org/Hosts/W32>`_


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

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

.. code-block:: shell

   git clone https://gitlab.com/qemu-project/qemu.git

When submitting patches, one common 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 `style section
<https://www.qemu.org/docs/master/devel/style.html>` of
the Developers Guide.

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

* `<https://qemu.org/Contribute/SubmitAPatch>`_
* `<https://qemu.org/Contribute/TrivialPatches>`_

The QEMU website is also maintained under source control.

.. code-block:: shell

  git clone https://gitlab.com/qemu-project/qemu-web.git

* `<https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/>`_

A 'git-publish' utility was created to make above process less
cumbersome, and is highly recommended for making regular contributions,
or even just for sending consecutive patch series revisions. It also
requires a working 'git send-email' setup, and by default doesn't
automate everything, so you may want to go through the above steps
manually for once.

For installation instructions, please go to

*  `<https://github.com/stefanha/git-publish>`_

The workflow with 'git-publish' is:

.. code-block:: shell

  $ git checkout master -b my-feature
  $ # work on new commits, add your 'Signed-off-by' lines to each
  $ git publish

Your patch series will be sent and tagged as my-feature-v1 if you need to refer
back to it in the future.

Sending v2:

.. code-block:: shell

  $ git checkout my-feature # same topic branch
  $ # making changes to the commits (using 'git rebase', for example)
  $ git publish

Your patch series will be sent with 'v2' tag in the subject and the git tip
will be tagged as my-feature-v2.

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:

* `<https://qemu.org/Contribute/ReportABug>`_


ChangeLog
=========

For version history and release notes, please visit
`<https://wiki.qemu.org/ChangeLog/>`_ or look at the git history for
more detailed information.


Contact
=======

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

* `<mailto:qemu-devel@nongnu.org>`_
* `<https://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:

* `<https://qemu.org/Contribute/StartHere>`_