Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200424084338.26803-4-armbru@redhat.com>

Call visit_check_list().  Missed in commit a4a1c70d "qapi: Make
input visitors detect unvisited list tails".

Drop an irrelevant error_propagate() while there.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200424084338.26803-3-armbru@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200424084338.26803-2-armbru@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415083048.14339-6-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

qdict_iter() has just three uses and no test coverage.  Replace by
qdict_first(), qdict_next() for more concise code and less type
punning.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415083048.14339-5-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

qlist_iter() has just three uses outside tests/.  Replace by
QLIST_FOREACH_ENTRY() for more concise code and less type punning.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415083048.14339-4-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415083048.14339-3-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
[Coding style in moved code tidied up]

QLIST_FOREACH_ENTRY() traverses a tail queue manually.  Use
QTAILQ_FIRST() and QTAILQ_NEXT() instead.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415083048.14339-2-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Miscellaneous patches for 2020-04-29

# gpg: Signature made Wed 29 Apr 2020 07:42:52 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-misc-2020-04-29: (32 commits)
  qemu-option: pass NULL rather than 0 to the id of qemu_opts_set()
  libqos: Give get_machine_allocator() internal linkage
  fuzz: Simplify how we compute available machines and types
  Makefile: Drop unused, broken target recurse-fuzz
  smbus: Fix spd_data_generate() for number of banks > 2
  bamboo, sam460ex: Tidy up error message for unsupported RAM size
  smbus: Fix spd_data_generate() error API violation
  sam460ex: Suppress useless warning on -m 32 and -m 64
  qga: Fix qmp_guest_suspend_{disk, ram}() error handling
  qga: Fix qmp_guest_get_memory_blocks() error handling
  tests/test-logging: Fix test for -dfilter 0..0xffffffffffffffff
  migration/colo: Fix qmp_xen_colo_do_checkpoint() error handling
  io: Fix qio_channel_socket_close() error handling
  xen/pt: Fix flawed conversion to realize()
  virtio-net: Fix duplex=... and speed=... error handling
  bochs-display: Fix vgamem=SIZE error handling
  fdc: Fix fallback=auto error handling
  arm/virt: Fix virt_machine_device_plug_cb() error API violation
  cpus: Proper range-checking for -icount shift=N
  cpus: Fix configure_icount() error API violation
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The second argument 'id' is a pointer. Pass NULL rather than 0.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Message-Id: <20200427005704.2475782-1-masahiroy@kernel.org>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200424071142.3525-4-armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

apply_to_qlist(), apply_to_node() work with QObjects.  This is
designed for use by tests/qtest/qos-test.c, which gets the data in
that form via QMP.  Goes back to commit fc281c80 "tests: qgraph API
for the qtest driver framework".

Commit 275ab39d "fuzz: add support for qos-assisted fuzz targets"
added another user: qtest/fuzz/qos_fuzz.c.  To get the data as
QObjects, it uses qmp_marshal_query_machines() and
qmp_marshal_qom_list_types().

All this code is rather cumbersome.  Switch to working with generated
QAPI types instead:

* Replace apply_to_qlist() & friends by machines_apply_to_node() and
  types_apply_to_node().

* Have qos_fuzz.c use qmp_query_machines() and qmp_qom_list_types()
  instead.

* Have qos_test.c convert from QObject to the QAPI types.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200424071142.3525-3-armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NAlexander Bulekov <alxndr@bu.edu>

Target recurse-fuzz depends on pc-bios/optionrom/fuzz, which can't be
made.  It's not used anywhere.  Added in commit c621dc3e, looks
like cargo cult.  Delete.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200424071142.3525-2-armbru@redhat.com>
Reviewed-by: NAlexander Bulekov <alxndr@bu.edu>

spd_data_generate() splits @ram_size bytes into @nbanks RAM banks of
1 << sz_log2 MiB each, like this:

    size = ram_size >> 20; /* work in terms of megabytes */
    [...]
    nbanks = 1;
    while (sz_log2 > max_log2 && nbanks < 8) {
        sz_log2--;
        nbanks++;
    }

Each iteration halves the size of a bank, and increments the number of
banks.  Wrong: it should double the number of banks.

The bug goes back all the way to commit b296b664 "smbus: Add a
helper to generate SPD EEPROM data".

It can't bite because spd_data_generate()'s current users pass only
@ram_size that result in *zero* iterations:

    machine     RAM size    #banks  type    bank size
    fulong2e     256 MiB         1   DDR      256 MiB
    sam460ex    2048 MiB         1   DDR2    2048 MiB
                1024 MiB         1   DDR2    1024 MiB
                 512 MiB         1   DDR2     512 MiB
                 256 MiB         1   DDR2     256 MiB
                 128 MiB         1   SDR      128 MiB
                  64 MiB         1   SDR       64 MiB
                  32 MiB         1   SDR       32 MiB

Apply the obvious, minimal fix.  I admit I'm tempted to rip out the
unused (and obviously untested) feature instead, because YAGNI.

Note that this is not the final result, as spd_data_generate() next
increases #banks from 1 to 2 if possible.  This is done "to avoid a
bug in MIPS Malta firmware".  We don't even use this function with
machine type malta.  *Shrug*
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422134815.1584-5-armbru@redhat.com>

Improve

    $ ppc-softmmu/qemu-system-ppc -M sam460ex -m 4096
    qemu-system-ppc: Max 1 banks of 2048 ,1024 ,512 ,256 ,128 ,64 ,32 MB DIMM/bank supported
    qemu-system-ppc: Possible valid RAM size: 2048

to

    qemu-system-ppc: at most 1 bank of 2048, 1024, 512, 256, 128, 64, 32 MiB each supported
    Possible valid RAM size: 1024 MiB
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422134815.1584-4-armbru@redhat.com>
Reviewed-by: NBALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

spd_data_generate() can pass @errp to error_setg() more than once when
it adjusts both memory size and type.  Harmless, because no caller
passes anything that needs adjusting.  Until the previous commit,
sam460ex passed types that needed adjusting, but not sizes.

spd_data_generate()'s contract is rather awkward:

    If everything's fine, return non-null and don't set an error.

    Else, if memory size or type need adjusting, return non-null and
    set an error describing the adjustment.

    Else, return null and set an error reporting why no data can be
    generated.

Its callers treat the error as a warning even when null is returned.
They don't create the "smbus-eeprom" device then.  Suspicious.

Since the previous commit, only "everything's fine" can actually
happen.  Drop the unused code and simplify the callers.  This gets rid
of the error API violation.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422134815.1584-3-armbru@redhat.com>

Requesting 32 or 64 MiB of RAM with the sam460ex machine type produces
a useless warning:

    qemu-system-ppc: warning: Memory size is too small for SDRAM type, adjusting type

This is because sam460ex_init() asks spd_data_generate() for DDR2,
which is impossible, so spd_data_generate() corrects it to DDR.

The warning goes back to commit 08fd9917 "sam460ex: Clean up SPD
EEPROM creation".

Make sam460ex_init() pass the correct SDRAM type to get rid of the
warning.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422134815.1584-2-armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second

qmp_guest_suspend_disk() and qmp_guest_suspend_ram() pass @local_err
first to check_suspend_mode(), then to acquire_privilege(), then to
execute_async().  Continuing after errors here can only end in tears.
For instance, we risk tripping error_setv()'s assertion.

Fixes: aa59637e
Fixes: f54603b6
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-15-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

qmp_guest_get_memory_blocks() passes &local_err to
transfer_memory_block() in a loop.  If this fails in more than one
iteration, it can trip error_setv()'s assertion.

Fix it to break the loop.

Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-14-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Fixes: 58e19e6eSigned-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-13-armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

qmp_xen_colo_do_checkpoint() passes @errp first to
replication_do_checkpoint_all(), and then to
colo_notify_filters_event().  If both fail, this will trip the
assertion in error_setv().

Similar code in secondary_vm_do_failover() calls
colo_notify_filters_event() only after replication_do_checkpoint_all()
succeeded.  Do the same here.

Fixes: 0e8818f0
Cc: Zhang Chen <chen.zhang@intel.com>
Cc: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NZhang Chen <chen.zhang@intel.com>
Message-Id: <20200422130719.28225-12-armbru@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

qio_channel_socket_close() passes @errp first to
socket_listen_cleanup(), and then, if closesocket() fails, to
error_setg_errno().  If socket_listen_cleanup() failed, this will trip
the assertion in error_setv().

Fix by ignoring a second error.

Fixes: 73564c40
Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200422130719.28225-11-armbru@redhat.com>

The conversion of xen_pt_initfn() to xen_pt_realize() blindly replaced
XEN_PT_ERR() by error_setg().  Several error conditions that did not
fail xen_pt_initfn() now fail xen_pt_realize().  Unsurprisingly, the
cleanup on these errors looks highly suspicious.

Revert the inappropriate replacements.

Fixes: 5a11d0f7
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Paul Durrant <paul@xen.org>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPaul Durrant <paul@xen.org>
Message-Id: <20200422130719.28225-10-armbru@redhat.com>

virtio_net_device_realize() rejects invalid duplex and speed values.
The error handling is broken:

    $ ../qemu/bld-sani/x86_64-softmmu/qemu-system-x86_64 -S -display none -monitor stdio
    QEMU 4.2.93 monitor - type 'help' for more information
    (qemu) device_add virtio-net,duplex=x
    Error: 'duplex' must be 'half' or 'full'
    (qemu) c
    =================================================================
    ==15654==ERROR: AddressSanitizer: heap-use-after-free on address 0x62e000014590 at pc 0x560b75c8dc13 bp 0x7fffdf1a6950 sp 0x7fffdf1a6940
    READ of size 8 at 0x62e000014590 thread T0
	#0 0x560b75c8dc12 in object_dynamic_cast_assert /work/armbru/qemu/qom/object.c:826
	#1 0x560b74c38ac0 in virtio_vmstate_change /work/armbru/qemu/hw/virtio/virtio.c:3210
	#2 0x560b74d9765e in vm_state_notify /work/armbru/qemu/softmmu/vl.c:1271
	#3 0x560b7494ba72 in vm_prepare_start /work/armbru/qemu/cpus.c:2156
	#4 0x560b7494bacd in vm_start /work/armbru/qemu/cpus.c:2162
	#5 0x560b75a7d890 in qmp_cont /work/armbru/qemu/monitor/qmp-cmds.c:160
	#6 0x560b75a8d70a in hmp_cont /work/armbru/qemu/monitor/hmp-cmds.c:1043
	#7 0x560b75a799f2 in handle_hmp_command /work/armbru/qemu/monitor/hmp.c:1082
    [...]

    0x62e000014590 is located 33168 bytes inside of 42288-byte region [0x62e00000c400,0x62e000016930)
    freed by thread T1 here:
	#0 0x7feadd39491f in __interceptor_free (/lib64/libasan.so.5+0x10d91f)
	#1 0x7feadcebcd7c in g_free (/lib64/libglib-2.0.so.0+0x55d7c)
	#2 0x560b75c8fd40 in object_unref /work/armbru/qemu/qom/object.c:1128
	#3 0x560b7498a625 in memory_region_unref /work/armbru/qemu/memory.c:1762
	#4 0x560b74999fa4 in do_address_space_destroy /work/armbru/qemu/memory.c:2788
	#5 0x560b762362fc in call_rcu_thread /work/armbru/qemu/util/rcu.c:283
	#6 0x560b761c8884 in qemu_thread_start /work/armbru/qemu/util/qemu-thread-posix.c:519
	#7 0x7fead9be34bf in start_thread (/lib64/libpthread.so.0+0x84bf)

    previously allocated by thread T0 here:
	#0 0x7feadd394d18 in __interceptor_malloc (/lib64/libasan.so.5+0x10dd18)
	#1 0x7feadcebcc88 in g_malloc (/lib64/libglib-2.0.so.0+0x55c88)
	#2 0x560b75c8cf8a in object_new /work/armbru/qemu/qom/object.c:699
	#3 0x560b75010ad9 in qdev_device_add /work/armbru/qemu/qdev-monitor.c:654
	#4 0x560b750120c2 in qmp_device_add /work/armbru/qemu/qdev-monitor.c:805
	#5 0x560b75012c1b in hmp_device_add /work/armbru/qemu/qdev-monitor.c:905
    [...]
    ==15654==ABORTING

Cause: virtio_net_device_realize() neglects to bail out after setting
the error.  Fix that.

Fixes: 9473939e
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200422130719.28225-9-armbru@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

bochs_display_realize() rejects out-of-range vgamem.  The error
handling is broken:

    $ qemu-system-x86_64 -S -display none -monitor stdio
    QEMU 4.2.93 monitor - type 'help' for more information
    (qemu) device_add bochs-display,vgamem=1
    Error: bochs-display: video memory too small
    (qemu) device_add bochs-display,vgamem=1
    RAMBlock "0000:00:04.0/bochs-display-vram" already registered, abort!
    Aborted (core dumped)

Cause: bochs_display_realize() neglects to bail out after setting the
error.  Fix that.

Fixes: 765c9429
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200422130719.28225-8-armbru@redhat.com>
Reviewed-by: NGerd Hoffmann <kraxel@redhat.com>

fdctrl_realize_common() rejects fallback=auto.  Used by devices
"isa-fdc", "sysbus-fdc", "SUNW,fdtwo".  The error handling is broken:

    $ qemu-system-x86_64 -nodefaults -device isa-fdc,fallback=auto,driveA=fd0 -drive if=none,id=fd0
    **
    ERROR:/work/armbru/qemu/hw/block/fdc.c:434:pick_drive_type: assertion failed: (drv->drive != FLOPPY_DRIVE_TYPE_AUTO)
    Aborted (core dumped)

Cause: fdctrl_realize_common() neglects to bail out after setting the
error.  Fix that.

Fixes: a73275dd
Cc: John Snow <jsnow@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200422130719.28225-7-armbru@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

virt_machine_device_plug_cb() passes @errp to
cryptodev_builtin_sym_close_session() in a loop.  Harmless, because
cryptodev_builtin_sym_close_session() can't actually fail.  Fix by
dropping its Error ** parameter.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm@nongnu.org
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200422130719.28225-6-armbru@redhat.com>

timers_state.icount_time_shift must be in [0,63] to avoid undefined
behavior when shifting by it, e.g. in cpu_icount_to_ns().
icount_adjust() clamps it to [0,MAX_ICOUNT_SHIFT], with
MAX_ICOUNT_SHIFT = 10.  configure_icount() doesn't.  Fix that.

Fixes: a8bfac37
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-5-armbru@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

configure_icount() is wrong that way.  Harmless, because its @errp is
always &error_abort or &error_fatal.

Just as wrong (and just as harmless): when it fails, it can still
update global state.

Fix all that.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-4-armbru@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

check_cache_dropped() calls error_setg() in a loop.  It fails to break
the loop in one instance.  If a subsequent iteration error_setg()s
again, it trips error_setv()'s assertion.

Fix it to break the loop.

Fixes: 31be8a2a
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200422130719.28225-3-armbru@redhat.com>

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

cryptodev_builtin_cleanup() passes @errp to
cryptodev_builtin_sym_close_session() in a loop.  Harmless, because
cryptodev_builtin_sym_close_session() can't actually fail.  Fix it
anyway.

Cc: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200422130719.28225-2-armbru@redhat.com>

qemu-img create, convert, amend, and measure use accumulate_options()
to merge multiple -o options.  This is broken for -o "":

    $ qemu-img create -f qcow2 -o backing_file=a -o "" -o backing_fmt=raw,size=1M new.qcow2
    qemu-img: warning: Could not verify backing image. This may become an error in future versions.
    Could not open 'a,backing_fmt=raw': No such file or directory
    Formatting 'new.qcow2', fmt=qcow2 size=1048576 backing_file=a,,backing_fmt=raw cluster_size=65536 lazy_refcounts=off refcount_bits=16
    $ qemu-img info new.qcow2
    image: new.qcow2
    file format: qcow2
    virtual size: 1 MiB (1048576 bytes)
    disk size: 196 KiB
    cluster_size: 65536
--> backing file: a,backing_fmt=raw
    Format specific information:
        compat: 1.1
        lazy refcounts: false
        refcount bits: 16
        corrupt: false

Merging these three -o the obvious way is wrong, because it results in
an unwanted ',' escape:

    backing_file=a,,backing_fmt=raw,size=1M
                  ~~

We could silently drop -o "", but Kevin asked me to reject it instead.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415074927.19897-10-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

is_valid_option_list()'s purpose is ensuring qemu-img.c's can safely
join multiple parameter strings separated by ',' like this:

        g_strdup_printf("%s,%s", params1, params2);

How it does that is anything but obvious.  A close reading of the code
reveals that it fails exactly when its argument starts with ',' or
ends with an odd number of ','.  Makes sense, actually, because when
the argument starts with ',', a separating ',' preceding it would get
escaped, and when it ends with an odd number of ',', a separating ','
following it would get escaped.

Move it to qemu-img.c and rewrite it the obvious way.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200415074927.19897-9-armbru@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-Id: <20200415074927.19897-8-armbru@redhat.com>

When opts_parse() sets @invalidp to true, qemu_opts_parse_noisily()
uses has_help_option() to decide whether to print help.  This parses
the input string a second time.

Easy to avoid: replace @invalidp by @help_wanted.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20200415074927.19897-7-armbru@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-Id: <20200415074927.19897-6-armbru@redhat.com>

has_help_option() uses its own parser.  It's inconsistent with
qemu_opts_parse(), as demonstrated by test-qemu-opts case
/qemu-opts/has_help_option.  Fix by reusing the common parser.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200415074927.19897-5-armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-Id: <20200415074927.19897-4-armbru@redhat.com>

The next commits will put it to use.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-Id: <20200415074927.19897-3-armbru@redhat.com>