Include qemu-common.h exactly where needed

No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Me

Include qemu-common.h exactly where needed

No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]

show more ...

Include qemu/module.h where needed, drop it from qemu-common.h

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-4-armbru@redhat.com>
[Rebased with conflicts res

Include qemu/module.h where needed, drop it from qemu-common.h

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-4-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
hw/usb/dev-hub.c hw/misc/exynos4210_rng.c hw/misc/bcm2835_rng.c
hw/misc/aspeed_scu.c hw/display/virtio-vga.c hw/arm/stm32f205_soc.c;
ui/cocoa.m fixed up]

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block: Add BlockBackend.ctx

This adds a new parameter to blk_new() which requires its callers to
declare from which AioContext this BlockBackend is going to be used (or
the locks of which AioContext

block: Add BlockBackend.ctx

This adds a new parameter to blk_new() which requires its callers to
declare from which AioContext this BlockBackend is going to be used (or
the locks of which AioContext need to be taken anyway).

The given context is only stored and kept up to date when changing
AioContexts. Actually applying the stored AioContext to the root node
is saved for another commit.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: rebase: Reuse in-chain BlockDriverState

If a chain was detected, don't open a new BlockBackend from the target
backing file which will create a new BlockDriverState. Instead, create
an emp

qemu-img: rebase: Reuse in-chain BlockDriverState

If a chain was detected, don't open a new BlockBackend from the target
backing file which will create a new BlockDriverState. Instead, create
an empty BlockBackend and attach the already open BlockDriverState.

Permissions for blk_new() were copied from blk_new_open() when
flags = 0.

Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Signed-off-by: Sagi Amit <sagi.amit@oracle.com>
Co-developed-by: Sagi Amit <sagi.amit@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Message-id: 20190523163337.4497-4-shmuel.eiderman@oracle.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

show more ...

qemu-img: rebase: Reduce reads on in-chain rebase

In the following case:

(base) A <- B <- C (tip)

when running:

qemu-img rebase -b A C

QEMU would read all sectors not allocated in the file b

qemu-img: rebase: Reduce reads on in-chain rebase

In the following case:

(base) A <- B <- C (tip)

when running:

qemu-img rebase -b A C

QEMU would read all sectors not allocated in the file being rebased (C)
and compare them to the new base image (A), regardless of whether they
were changed or even allocated anywhere along the chain between the new
base and the top image (B). This causes many unneeded reads when
rebasing an image which represents a small diff of a large disk, as it
would read most of the disk's sectors.

Instead, use bdrv_is_allocated_above() to reduce the number of
unnecessary reads.

Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Message-id: 20190523163337.4497-3-shmuel.eiderman@oracle.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

show more ...

qemu-img: rebase: Reuse parent BlockDriverState

In safe mode we open the entire chain, including the parent backing
file of the rebased file.
Do not open a new BlockBackend for the parent backing fi

qemu-img: rebase: Reuse parent BlockDriverState

In safe mode we open the entire chain, including the parent backing
file of the rebased file.
Do not open a new BlockBackend for the parent backing file, which
saves opening the rest of the chain twice, which for long chains
saves many "pricy" bdrv_open() calls.

Permissions for blk_new() were copied from blk_new_open() when
flags = 0.

Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Signed-off-by: Sagi Amit <sagi.amit@oracle.com>
Co-developed-by: Sagi Amit <sagi.amit@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Message-id: 20190523163337.4497-2-shmuel.eiderman@oracle.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

show more ...

qemu-img: Use zero writes after source backing EOF

Past the end of the source backing file, we memset() buf_old to zero, so
it is clearly easy to use blk_pwrite_zeroes() instead of blk_pwrite()
then

qemu-img: Use zero writes after source backing EOF

Past the end of the source backing file, we memset() buf_old to zero, so
it is clearly easy to use blk_pwrite_zeroes() instead of blk_pwrite()
then.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: Allow rebase with no input base

Currently, without -u, you cannot add a backing file to an image when it
currently has none:

$ qemu-img rebase -b base.qcow2 foo.qcow2
qemu-img: Could not

qemu-img: Allow rebase with no input base

Currently, without -u, you cannot add a backing file to an image when it
currently has none:

$ qemu-img rebase -b base.qcow2 foo.qcow2
qemu-img: Could not open old backing file '': The 'file' block driver
requires a file name

It is really simple to allow this, though (effectively by setting
old_backing_size to 0), so this patch does just that.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: Use IEC binary prefixes for size constants

Using IEC binary prefixes in order to make the code more readable.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin

qemu-img: Use IEC binary prefixes for size constants

Using IEC binary prefixes in order to make the code more readable.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: use buffer-based io

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redh

qemu-img: use buffer-based io

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: Make create hint at protocol options

qemu-img create allows giving just a format and "-o help" to get a list
of the options supported by that format. Users may not realize that the
protoc

qemu-img: Make create hint at protocol options

qemu-img create allows giving just a format and "-o help" to get a list
of the options supported by that format. Users may not realize that the
protocol level may offer even more options, which they only get to see
by specifying a filename.

This patch adds a note to hint at that fact.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

block/qapi: Clean up how we print to monitor or stdout

bdrv_snapshot_dump(), bdrv_image_info_specific_dump(),
bdrv_image_info_dump() and their helpers take an fprintf()-like
callback and a FILE * to

block/qapi: Clean up how we print to monitor or stdout

bdrv_snapshot_dump(), bdrv_image_info_specific_dump(),
bdrv_image_info_dump() and their helpers take an fprintf()-like
callback and a FILE * to pass to it.

hmp.c passes monitor_printf() cast to fprintf_function and the current
monitor cast to FILE *.

qemu-img.c and qemu-io-cmds.c pass fprintf and stdout.

The type-punning is technically undefined behaviour, but works in
practice. Clean up: drop the callback, and call qemu_printf()
instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190417191805.28198-8-armbru@redhat.com>

show more ...

qemu-img: Use error_vreport() in error_exit()

error_exit() uses low-level error_printf() to report errors.
Modernize it to use error_vreport().

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mrei

qemu-img: Use error_vreport() in error_exit()

error_exit() uses low-level error_printf() to report errors.
Modernize it to use error_vreport().

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190417190641.26814-2-armbru@redhat.com>

show more ...

log: Make glib logging go through QEMU

This commit adds a error_init() helper which calls
g_log_set_default_handler() so that glib logs (g_log, g_warning, ...)
are handled similarly to other QEMU lo

log: Make glib logging go through QEMU

This commit adds a error_init() helper which calls
g_log_set_default_handler() so that glib logs (g_log, g_warning, ...)
are handled similarly to other QEMU logs. This means they will get a
timestamp if timestamps are enabled, and they will go through the
HMP monitor if one is configured.

This commit also adds a call to error_init() to the binaries
installed by QEMU. Since error_init() also calls error_set_progname(),
this means that *-linux-user, *-bsd-user and qemu-pr-helper messages
output with error_report, info_report, ... will slightly change: they
will be prefixed by the binary name.

glib debug messages are enabled through G_MESSAGES_DEBUG similarly to
the glib default log handler.

At the moment, this change will mostly impact SPICE logging if your
spice version is >= 0.14.1. With older spice versions, this is not going
to work as expected, but will not have any ill effect, so this call is
not conditional on the SPICE version.

Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20190131164614.19209-3-cfergeau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

show more ...

qemu-img: Enable BDRV_REQ_MAY_UNMAP in convert

With Kevin's "block: Fix slow pre-zeroing in qemu-img convert"[1]
(commit c9fdcf202f, 'qemu-img: Use BDRV_REQ_NO_FALLBACK for
pre-zeroing') we skip the

qemu-img: Enable BDRV_REQ_MAY_UNMAP in convert

With Kevin's "block: Fix slow pre-zeroing in qemu-img convert"[1]
(commit c9fdcf202f, 'qemu-img: Use BDRV_REQ_NO_FALLBACK for
pre-zeroing') we skip the pre zero step called like this:

blk_make_zero(s->target, BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK)

And we write zeroes later using:

blk_co_pwrite_zeroes(s->target,
sector_num << BDRV_SECTOR_BITS,
n << BDRV_SECTOR_BITS, 0);

Since we use flags=0, this is translated to NBD_CMD_WRITE_ZEROES with
NBD_CMD_FLAG_NO_HOLE flag, which cause the NBD server to allocated space
instead of punching a hole.

Here is an example failure:

$ dd if=/dev/urandom of=src.img bs=1M count=5
$ truncate -s 50m src.img
$ truncate -s 50m dst.img
$ nbdkit -f -v -e '' -U nbd.sock file file=dst.img

$ ./qemu-img convert -n src.img nbd:unix:nbd.sock

We can see in nbdkit log that it received the NBD_CMD_FLAG_NO_HOLE
(may_trim=0):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=0
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=0
nbdkit: file[1]: debug: flush

And the image became fully allocated:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 50M

With this change we see that nbdkit did not receive the
NBD_CMD_FLAG_NO_HOLE (may_trim=1):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=1
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=1
nbdkit: file[1]: debug: flush

And the file is sparse as expected:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 5.0M

[1] http://lists.nongnu.org/archive/html/qemu-block/2019-03/msg00761.html

Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: Gracefully shutdown when map can't finish

Trying 'qemu-img map -f raw nbd://localhost:10809' causes the
NBD server to output a scary message:

qemu-nbd: Disconnect client, due to: Failed t

qemu-img: Gracefully shutdown when map can't finish

Trying 'qemu-img map -f raw nbd://localhost:10809' causes the
NBD server to output a scary message:

qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end-of-file before all bytes were read

This is because the NBD client, being remote, has no way to expose a
human-readable map (the --output=json data is fine, however). But
because we exit(1) right after the message, causing the client to
bypass all block cleanup, the server sees the abrupt exit and warns,
whereas it would be silent had the client had a chance to send
NBD_CMD_DISC. Other protocols may have similar cleanup issues, where
failure to blk_unref() could cause unintended effects.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190326184043.7544-1-eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: Report bdrv_block_status failures

If bdrv_block_status_above() fails, we are aborting the convert
process but failing to print an error message. Broken in commit
690c7301 (v2.4) when rewr

qemu-img: Report bdrv_block_status failures

If bdrv_block_status_above() fails, we are aborting the convert
process but failing to print an error message. Broken in commit
690c7301 (v2.4) when rewriting convert's logic.

Discovered when teaching nbdkit to support NBD_CMD_BLOCK_STATUS, and
accidentally violating the protocol by returning more than one extent
in spite of qemu asking for NBD_CMD_FLAG_REQ_ONE. The qemu NBD code
should probably handle the server's non-compliance more gracefully
than failing with EINVAL, but qemu-img shouldn't be silently
squelching any block status failures. It doesn't help that qemu 3.1
masks the qemu-img bug with extra noise that the nbd code is dumping
to stderr (that noise was cleaned up in d8b4bad8).

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190323212639.579-2-eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

show more ...

qemu-img: Use BDRV_REQ_NO_FALLBACK for pre-zeroing

If qemu-img convert sees that the target image isn't zero-initialised
yet, it tries to do an efficient zero write for the whole image first
to save

qemu-img: Use BDRV_REQ_NO_FALLBACK for pre-zeroing

If qemu-img convert sees that the target image isn't zero-initialised
yet, it tries to do an efficient zero write for the whole image first
to save the overhead of repeated explicit zero writes during the
conversion. Obviously, this provides only an advantage if the
pre-zeroing is actually efficient. Otherwise, we can end up writing
zeroes slowly while zeroing out the whole image, and then overwrite the
same blocks again with real data, potentially doubling the written data.

Pass BDRV_REQ_NO_FALLBACK to blk_make_zero() to avoid this case. If we
can't efficiently zero out, we'll instead write explicit zeroes only if
there is no data to be written to a block.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>

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block: iterate_format with account of whitelisting

bdrv_iterate_format (which is currently only used for printing out the
formats supported by the block layer) doesn't take format whitelisting
into

block: iterate_format with account of whitelisting

bdrv_iterate_format (which is currently only used for printing out the
formats supported by the block layer) doesn't take format whitelisting
into account.

This creates a problem for tests: they enumerate supported formats to
decide which tests to enable, but then discover that QEMU doesn't let
them actually use some of those formats.

To avoid that, exclude formats that are not whitelisted from
enumeration, if whitelisting is in use. Since we have separate
whitelists for r/w and r/o, take this a parameter to
bdrv_iterate_format, and print two lists of supported formats (r/w and
r/o) in main qemu.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

block: bdrv_get_full_backing_filename_from_...'s ret. val.

Make bdrv_get_full_backing_filename_from_filename() return an allocated
string instead of placing the result in a caller-provided buffer.

block: bdrv_get_full_backing_filename_from_...'s ret. val.

Make bdrv_get_full_backing_filename_from_filename() return an allocated
string instead of placing the result in a caller-provided buffer.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-11-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

show more ...

block: Use bdrv_refresh_filename() to pull

Before this patch, bdrv_refresh_filename() is used in a pushing manner:
Whenever the BDS graph is modified, the parents of the modified edges
are supposed

block: Use bdrv_refresh_filename() to pull

Before this patch, bdrv_refresh_filename() is used in a pushing manner:
Whenever the BDS graph is modified, the parents of the modified edges
are supposed to be updated (recursively upwards). However, that is
nonviable, considering that we want child changes not to concern
parents.

Also, in the long run we want a pull model anyway: Here, we would have a
bdrv_filename() function which returns a BDS's filename, freshly
constructed.

This patch is an intermediate step. It adds bdrv_refresh_filename()
calls before every place a BDS.filename value is used. The only
exceptions are protocol drivers that use their own filename, which
clearly would not profit from refreshing that filename before.

Also, bdrv_get_encrypted_filename() is removed along the way (as a user
of BDS.filename), since it is completely unused.

In turn, all of the calls to bdrv_refresh_filename() before this patch
are removed, because we no longer have to call this function on graph
changes.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190201192935.18394-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

show more ...

qemu-img: fix error reporting for -object

Error reporting for user_creatable_add_opts_foreach was changed so that
it no longer called 'error_report_err' in:

commit 7e1e0c11127bde81cff260fc6859690

qemu-img: fix error reporting for -object

Error reporting for user_creatable_add_opts_foreach was changed so that
it no longer called 'error_report_err' in:

commit 7e1e0c11127bde81cff260fc6859690435c509d6
Author: Markus Armbruster <armbru@redhat.com>
Date: Wed Oct 17 10:26:43 2018 +0200

qom: Clean up error reporting in user_creatable_add_opts_foreach()

Some callers were updated to pass in "&error_fatal" but all the ones in
qemu-img were left passing NULL. As a result all errors went to
/dev/null instead of being reported to the user.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

block/snapshot: remove bdrv_snapshot_delete_by_id_or_name

After the previous patch, the only instance of this function left
is inside qemu-img.c.

qemu-img is using it inside the 'img_snapshot' func

block/snapshot: remove bdrv_snapshot_delete_by_id_or_name

After the previous patch, the only instance of this function left
is inside qemu-img.c.

qemu-img is using it inside the 'img_snapshot' function to delete
snapshots in the SNAPSHOT_DELETE case, based on a "snapshot_name"
string that refers to the tag, not ID, of the QEMUSnapshotInfo struct.
This can be verified by checking the SNAPSHOT_CREATE case that
comes shortly before SNAPSHOT_DELETE. In that case, the same
"snapshot_name" variable is being strcpy to the 'name' field
of the QEMUSnapshotInfo struct sn:

pstrcpy(sn.name, sizeof(sn.name), snapshot_name);

Based on that, it is unlikely that "snapshot_name" might contain
an "id" in SNAPSHOT_DELETE.

This patch changes SNAPSHOT_DELETE to use snapshot_find() and
snapshot_delete() instead of bdrv_snapshot_delete_by_id_or_name.
After that, there is no instances left of bdrv_snapshot_delete_by_id_or_name
in the code, so it is safe to remove it entirely.

Suggested-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

qemu-img: use qemu_iovec_init_buf

Use new qemu_iovec_init_buf() instead of
qemu_iovec_init_external( ... , 1), which simplifies the code.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@vir

qemu-img: use qemu_iovec_init_buf

Use new qemu_iovec_init_buf() instead of
qemu_iovec_init_external( ... , 1), which simplifies the code.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190218140926.333779-13-vsementsov@virtuozzo.com
Message-Id: <20190218140926.333779-13-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

qemu-io: Add generic function for reinitializing optind.

On FreeBSD 11.2:

$ nbdkit memory size=1M --run './qemu-io -f raw -c "aio_write 0 512" $nbd'
Parsing error: non-numeric argument, or extr

qemu-io: Add generic function for reinitializing optind.

On FreeBSD 11.2:

$ nbdkit memory size=1M --run './qemu-io -f raw -c "aio_write 0 512" $nbd'
Parsing error: non-numeric argument, or extraneous/unrecognized suffix -- aio_write

After main option parsing, we reinitialize optind so we can parse each
command. However reinitializing optind to 0 does not work on FreeBSD.
What happens when you do this is optind remains 0 after the option
parsing loop, and the result is we try to parse argv[optind] ==
argv[0] == "aio_write" as if it was the first parameter.

The FreeBSD manual page says:

In order to use getopt() to evaluate multiple sets of arguments, or to
evaluate a single set of arguments multiple times, the variable optreset
must be set to 1 before the second and each additional set of calls to
getopt(), and the variable optind must be reinitialized.

(From the rest of the man page it is clear that optind must be
reinitialized to 1).

The glibc man page says:

A program that scans multiple argument vectors, or rescans the same
vector more than once, and wants to make use of GNU extensions such as
'+' and '-' at the start of optstring, or changes the value of
POSIXLY_CORRECT between scans, must reinitialize getopt() by resetting
optind to 0, rather than the traditional value of 1. (Resetting to 0
forces the invocation of an internal initialization routine that
rechecks POSIXLY_CORRECT and checks for GNU extensions in optstring.)

This commit introduces an OS-portability function called
qemu_reset_optind which provides a way of resetting optind that works
on FreeBSD and platforms that use optreset, while keeping it the same
as now on other platforms.

Note that the qemu codebase sets optind in many other places, but in
those other places it's setting a local variable and not using getopt.
This change is only needed in places where we are using getopt and the
associated global variable optind.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20190118101114.11759-2-rjones@redhat.com
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

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