Commit Graph

55 Commits

Author SHA1 Message Date
Markus Armbruster
10b7c5dd0d qga: Fix memory allocation pasto
qmp_guest_file_seek() allocates memory for a GuestFileRead object
instead of the GuestFileSeek object it actually uses.  Harmless,
because the GuestFileRead is slightly larger.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2014-02-23 13:13:52 -06:00
Michal Privoznik
2c958923bc qga: Don't require 'time' argument in guest-set-time command
As the description to the guest-set-time states, the command is
there to ease time synchronization after resume. If guest was
suspended for longer period of time, its system time can go off
so badly, that even NTP refuses to set it. That's why the command
was invented: to give users chance to set the time (not
necessarily 100% correct). However, there's is no real need for
us to require users to pass an arbitrary time. Especially if we
can read the correct value from RTC (boiling down to reading
host's time). Hence this commit enables logic:

guest-set-time() == guest-set-time($now_from_rtc)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2014-02-23 13:11:56 -06:00
Markus Armbruster
84d18f065f Use error_is_set() only when necessary
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out.  Unnecessarily hard for
optimizers, static checkers, and human readers.  Dumb it down to
obvious.

Gets rid of several dozen Coverity false positives.

Note that the obvious form is already used in many places.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-02-17 11:57:23 -05:00
Stefan Weil
d607a52364 qga: Fix compiler warnings (missing format attribute, wrong format strings)
gcc 4.8.2 reports this warning when extra warnings are enabled (-Wextra):

  CC    qga/commands.o
qga/commands.c: In function ‘slog’:
qga/commands.c:28:5: error:
 function might be possible candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
     ^

gcc 4.8.2 reports this warning when slog is declared with the
gnu_printf format attribute:

qga/commands-posix.c: In function ‘qmp_guest_file_open’:
qga/commands-posix.c:404:5: warning:
 format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int64_t’ [-Wformat=]
     slog("guest-file-open, handle: %d", handle);
     ^

On 32 bit hosts there are three more warnings which are also fixed here.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-11-21 17:39:25 +01:00
whitearchey
485e741cd1 qga: Fix shutdown command of guest agent to work with SysV
For now guest agent uses following command to shutdown system:
shutdown -P +0 "blabla"
but this syntax works only with shutdown command from systemd or upstart,
because SysV shutdown requires -h switch.

Following patch changes the command so it works with systemd, upstart and SysV

With upstart/systemd qga use one of thee commands, depending on 'mode' parameter:
  shutdown -P +0 "..."
  shutdown -H +0 "..."
  shutdown -r +0 "..."
SysV equivalents for these are:
  shutdown -h -P +0 "..."
  shutdown -h -H +0 "..."
  shutdown -h -r +0 "..."
and these retain their meaning with upstart/systemd.

According to FreeBSD manpages, shutdown does not accept -P and -H options. Commands should be:
  shutdown -p +0 "..."
  shutdown -h +0 "..."
  shutdown -r +0 "..."

shutdown in Solaris does not accept any of -hHpPr and does not accept time in "+0" format

Signed-off-by: Michael Avdienko <whitearchey@gmail.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-11-16 14:04:45 +04:00
Tomoki Sekiyama
e5d9adbdab qemu-ga: execute fsfreeze-freeze in reverse order of mounts
Currently, fsfreeze-freeze may cause deadlock if a guest has loopback mounts
of image files in its disk; e.g.:

    # mount | grep ^/
    /dev/vda1 / type ext4 (rw,noatime,seclabel,data=ordered)
    /tmp/disk.img on /mnt type ext4 (rw,relatime,seclabel)

To avoid the deadlock, this freezes filesystems in reverse order of mounts.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
*fix up commit msg
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-10-10 14:52:37 -05:00
Laszlo Ersek
2b72001806 qga: unlink just created guest-file if fchmod() or fdopen() fails on it
We shouldn't allow guest filesystem pollution on error paths.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-05-13 09:45:49 -05:00
Laszlo Ersek
8fe6bbca71 qga: distinguish binary modes in "guest_file_open_modes" map
In Windows guests this may make a difference.

Since the original patch (commit c689b4f1) sought to be pedantic and to
consider theoretical corner cases of portability, we should fix it up
where it failed to come through in that pursuit.

Suggested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-05-13 09:45:49 -05:00
Laszlo Ersek
c689b4f1ba qga: set umask 0077 when daemonizing (CVE-2013-2007)
The qemu guest agent creates a bunch of files with insecure permissions
when started in daemon mode. For example:

  -rw-rw-rw- 1 root root /var/log/qemu-ga.log
  -rw-rw-rw- 1 root root /var/run/qga.state
  -rw-rw-rw- 1 root root /var/log/qga-fsfreeze-hook.log

In addition, at least all files created with the "guest-file-open" QMP
command, and all files created with shell output redirection (or
otherwise) by utilities invoked by the fsfreeze hook script are affected.

For now mask all file mode bits for "group" and "others" in
become_daemon().

Temporarily, for compatibility reasons, stick with the 0666 file-mode in
case of files newly created by the "guest-file-open" QMP call. Do so
without changing the umask temporarily.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-07 06:46:26 -05:00
Peter Maydell
085d813407 Fix typos and misspellings
Fix various typos and misspellings. The bulk of these were found with
codespell.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-22 13:25:07 +01:00
Laszlo Ersek
cbb65fc27f qga: implement qmp_guest_set_vcpus() for Linux with sysfs
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-03-11 18:58:30 -05:00
Laszlo Ersek
d2baff6253 qga: implement qmp_guest_get_vcpus() for Linux with sysfs
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-03-11 18:58:25 -05:00
Laszlo Ersek
70e133a708 qga: introduce guest-get-vcpus / guest-set-vcpus with stubs
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-03-11 18:57:49 -05:00
Lei Li
a1bca57f75 qga: add guest-set-time command
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

*added stub for w32

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-03-11 18:53:47 -05:00
Lei Li
6912e6a94c qga: add guest-get-time command
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

*added stub for w32

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-03-11 18:53:47 -05:00
Michael Roth
39097daf15 qemu-ga: use key-value store to avoid recycling fd handles after restart
Hosts hold on to handles provided by guest-file-open for periods that can
span beyond the life of the qemu-ga process that issued them. Since these
are issued starting from 0 on every restart, we run the risk of issuing
duplicate handles after restarts/reboots.

As a result, users with a stale copy of these handles may end up
reading/writing corrupted data due to their existing handles effectively
being re-assigned to an unexpected file or offset.

We unfortunately do not issue handles as strings, but as integers, so a
solution such as using UUIDs can't be implemented without introducing a
new interface.

As a workaround, we fix this by implementing a persistent key-value store
that will be used to track the value of the last handle that was issued
across restarts/reboots to avoid issuing duplicates.

The store is automatically written to the same directory we currently
set via --statedir to track fsfreeze state, and so should be applicable
for stable releases where this flag is supported.

A follow-up can use this same store for handling fsfreeze state, but
that change is cosmetic and left out for now.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Cc: qemu-stable@nongnu.org

* fixed guest_file_handle_add() return value from uint64_t to int64_t
2013-03-11 18:53:47 -05:00
Markus Armbruster
10a2158f52 qemu-ga: Plug leaks on qmp_guest_network_get_interfaces() error paths
Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-28 13:46:54 -06:00
Markus Armbruster
6f6867493c qemu-ga: Plug memory leak in guest_fsfreeze_cleanup()
Neglects to free errors allocated by qmp_guest_fsfreeze_thaw().
Spotted by Coverity.

While there, drop the test whether return value is negative (it's
never true), and improve logging.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-28 13:46:18 -06:00
Stefan Weil
e4ada48242 Replace non-portable asprintf by g_strdup_printf
g_strdup_printf already handles OOM errors, so some error handling in
QEMU code can be removed.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-01-19 10:24:43 +00:00
Tomoki Sekiyama
ec0f694c11 qemu-ga: execute hook to quiesce the guest on fsfreeze-freeze/thaw
To use the online disk snapshot for online-backup, application-level
consistency of the snapshot image is required. However, currently the
guest agent can provide only filesystem-level consistency, and the
snapshot may contain dirty data, for example, incomplete transactions.
This patch provides the opportunity to quiesce applications before
snapshot is taken.

If --fsfreeze-hook option is specified, the hook is executed with
"freeze" argument before the filesystem is frozen by fsfreeze-freeze
command. As for fsfreeze-thaw command, the hook is executed with "thaw"
argument after the filesystem is thawed.

This patch depends on patchset to improve error reporting by Luiz Capitulino:
  http://lists.gnu.org/archive/html/qemu-devel/2012-11/msg03016.html

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>

*clarified usage in help output

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:12 -06:00
Luiz Capitulino
7b3760879b qemu-ga: guest_suspend(): improve error reporting
Most errors are QERR_UNDEFINED_ERROR today.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:12 -06:00
Luiz Capitulino
6b26e837a4 qemu-ga: bios_supports_mode(): improve error reporting
Most errors are QERR_UNDEFINED_ERROR today.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:12 -06:00
Luiz Capitulino
878a0ae0ab qemu-ga: qmp_guest_network_get_interfaces(): get rid of snprintf() + error_set()
Convert them to error_setg_errno().

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
071673b090 qemu-ga: qmp_guest_fstrim(): get rid of sprintf() + error_set()
Convert them to error_setg_errno().

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
617fbbc132 qemu-ga: qmp_guest_fsfreeze_*(): get rid of sprintf() + error_set()
Convert them to error_setg_errno().

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
261551d1cc qemu-ga: build_fs_mount_list(): take an Error argument
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
d220a6dfea qemu-ga: qmp_guest_shutdown(): improve error reporting
Most errors are QERR_UNDEFINED_ERROR. Also, adds ga_wait_child() as
a future commit will use it too.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
db3edb6655 qemu-ga: qmp_guest_file_*: improve error reporting
Use error_setg_errno() when possible with an improved error description.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:11 -06:00
Luiz Capitulino
3ac4b7c51e qemu-ga: qmp_guest_file_close(): fix fclose() error check
fclose() returns EOF on error.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:10 -06:00
Luiz Capitulino
a9de6d01df qemu-ga: guest_file_handle_find(): take an Error argument
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

*Fixed missing space character in error message

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-01-08 16:38:10 -06:00
Paolo Bonzini
1de7afc984 misc: move include files to include/qemu/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:32:39 +01:00
Paolo Bonzini
7b1b5d1913 qapi: move include files to include/qobject/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:31 +01:00
Aurelien Jarno
048d3612a5 Merge branch 'trivial-patches' of git://github.com/stefanha/qemu
* 'trivial-patches' of git://github.com/stefanha/qemu:
  versatilepb: Use symbolic indices for ARM PIC
  qdev: kill bogus comment
  qemu-barrier: Fix compiler version check for future gcc versions
  hw: Add missing 'static' attribute for QEMUMachine
  cleanup useless return sentence
  qemu-sockets: Fix compiler warning (regression for MinGW)
  vnc: Fix spelling (hellmen -> hellman) in comment
  slirp: Fix spelling in comment (enought -> enough, insure -> ensure)
  tcg/arm: Use tcg_out_mov_reg rather than inline equivalent code
  cpu: Add missing 'static' attribute to qemu_global_mutex
  configure: Support empty target list (--target-list=)
  hw: Fix return value check for bdrv_read, bdrv_write
2012-10-06 18:54:14 +02:00
Amos Kong
4d5b97da35 cleanup useless return sentence
This patch cleans up return sentences in the end of void functions.

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
2012-10-05 15:10:21 +02:00
Jim Meyering
1ab516ed9b qemu-ga: prefer pstrcpy: consistently NUL-terminate ifreq.ifr_name
NUL-termination of the .ifr_name field is not required, but is fine
(and preferable to using strncpy and leaving the reader to wonder),
since the first thing the linux kernel does is to clear the last byte.
Besides, using pstrcpy here makes this setting of ifr_name consistent
with the other code (e.g., net/tap-linux.c) that does the same thing.

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-10-05 07:58:37 -05:00
Paolo Bonzini
eab5fd5989 qemu-ga: add guest-fstrim command
FITRIM is a mounted filesystem feature to discard (or "trim") blocks which
are not in use by the filesystem. This is useful for solid-state drives
(SSDs) and thinly-provisioned storage.  Provide access to the feature
from the host so that filesystems can be trimmed periodically or before
migration.

Here is an example using scsi_debug:

    # modprobe scsi_debug lbpu=1 lbpws=1
    # sg_vpd -p0xb2 /dev/sdb
    Logical block provisioning VPD page (SBC):
      Unmap command supported (LBPU): 1
      Write same (16) with unmap bit supported (LBWS): 1
      Write same (10) with unmap bit supported (LBWS10): 0
    # mke2fs /dev/sdb
    # cat /sys/bus/pseudo/drivers/scsi_debug/map
    1-616,16257-16383
    # mount /dev/sdb /run/media/pbonzini/test
    # dd if=/dev/zero of=/run/media/pbonzini/test/file
    # cat map
    1-616,645-1588,1599-4026,4029-16383
    # rm /run/media/pbonzini/test/file
    # ./qemu-ga /dev/fd/0
    {"execute":"guest-fstrim"}
    {"return": {}}
    # cat map
    1-612

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-06-21 17:59:27 -05:00
Paolo Bonzini
af02203fbe qemu-ga: make names more generic for mount list functions
We will use these functions and types for more than FSFREEZE, so rename them.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-06-21 17:59:18 -05:00
Michael Roth
9e2fa418fb qemu-ga: avoid blocking on atime update when reading /etc/mtab
Currently we re-read/re-process /etc/mtab to get an updated list of
mounts when guest-fsfreeze-thaw is called. This can cause an atime
update on /etc/mtab, which will block if we're in a frozen state.

Instead, use /proc's version of mtab, which may not be up-to-date with
options passed via -o remount, but is compatible for our use cases since
we only care about the filesystem type.

Reported-by: Matsuda, Daiki <matsudadik@intellilink.co.jp>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-29 21:00:42 -05:00
Andreas Färber
eecae14724 qemu-ga: Fix use of environ on Darwin
Use _NSGetEnviron() helper to access the environment.

Signed-off-by: Andreas Färber <andreas.faerber@web.de>
Cc: Charlie Somerville <charlie@charliesomerville.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-29 21:00:40 -05:00
Luiz Capitulino
2c02cbf6e9 qemu-ga: Fix missing environ declaration
Commit 3674838cd0 uses the environ global
variable, but is relying on environ to be declared somewhere else.

This worked for me because on F16 environ is declared in <unistd.h>, but
that doesn't happen in OpenBSD for example, causing a build failure.

This commit fixes the build error by declaring environ if it hasn't
being declared yet.

Also fixes a build warning due to a missing <sys/wait.h> include.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-24 13:06:33 -05:00
Luiz Capitulino
3674838cd0 qemu-ga: guest-shutdown: use only async-signal-safe functions
POSIX mandates[1] that a child process of a multi-thread program uses
only async-signal-safe functions before exec(). We consider qemu-ga
to be multi-thread, because it uses glib.

However, qmp_guest_shutdown() uses functions that are not
async-signal-safe. Fix it the following way:

- fclose() -> reopen_fd_to_null()
- execl() -> execle()
- exit() -> _exit()
- drop slog() usage (which is not safe)

  [1] http://pubs.opengroup.org/onlinepubs/009695399/functions/fork.html

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
d5dd3498eb qemu-ga: guest-shutdown: become synchronous
Last commit dropped qemu-ga's SIGCHLD handler, used to automatically
reap terminated children processes. This introduced a bug to
qmp_guest_shutdown(): it will generate zombies.

This problem probably doesn't matter in the success case, as the VM
will shutdown anyway, but let's do the right thing and reap the
created process. This ultimately means that guest-shutdown is now a
synchronous command.

An interesting side effect is that guest-shutdown is now able to
report an error to the client if shutting down fails.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
dc8764f061 qemu-ga: guest-suspend: make the API synchronous
Currently, qemu-ga has a SIGCHLD handler that automatically reaps terminated
children processes. The idea is to avoid having qemu-ga commands blocked
waiting for children to terminate.

That approach has two problems:

 1. qemu-ga is unable to detect errors in the child, meaning that qemu-ga
    returns success even if the child fails to perform its task

 2. if a command does depend on the child exit status, the command has to
    play tricks to bypass the automatic reaper

Case 2 impacts the guest-suspend-* API, because it has to execute an external
program to check for suspend support. Today, to bypass the automatic reaper,
suspend code has to double fork and pass exit status information through a
pipe. Besides being complex, this is prone to race condition bugs. Indeed,
the current code does have such bugs.

Making the guest-suspend-* API synchronous (ie. by dropping the SIGCHLD
handler and calling waitpid() from commands) is a much simpler approach,
which fixes current race conditions bugs and enables commands to detect
errors in the child.

This commit does just that. There's a side effect though, guest-shutdown
will generate zombies if shutting down fails. This will be fixed by the
next commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
04b4e75f33 qemu-ga: make reopen_fd_to_null() public
The next commit wants to use it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Jim Meyering
a31f053129 fix some common typos
These were identified using: http://github.com/lyda/misspell-check
and run like this to create a bourne shell script using GNU sed's
-i option:

git ls-files|grep -vF .bin | misspellings -f - |grep -v '^ERROR:' |perl \
-pe 's/^(.*?)\[(\d+)\]: (\w+) -> "(.*?)"$/sed -i '\''${2}s!$3!$4!'\'' $1/'

Manually eliding the FP, "rela->real" and resolving "addres" to
address (not "adders") we get this:

  sed -i '450s!thru!through!' Changelog
  sed -i '260s!neccessary!necessary!' coroutine-sigaltstack.c
  sed -i '54s!miniscule!minuscule!' disas.c
  sed -i '1094s!thru!through!' hw/usb/hcd-ehci.c
  sed -i '1095s!thru!through!' hw/usb/hcd-ehci.c
  sed -i '21s!unecessary!unnecessary!' qapi-schema-guest.json
  sed -i '307s!explictly!explicitly!' qemu-ga.c
  sed -i '490s!preceeding!preceding!' qga/commands-posix.c
  sed -i '792s!addres!address!' qga/commands-posix.c
  sed -i '6s!beeing!being!' tests/tcg/test-mmap.c

Also, manually fix "arithmentic", spotted by Peter Maydell:

  sed -i 's!arithmentic!arithmetic!' coroutine-sigaltstack.c

Signed-off-by: Jim Meyering <meyering@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2012-05-14 07:27:24 +02:00
Michael Roth
f22d85e9e6 qemu-ga: add a whitelist for fsfreeze-safe commands
Currently we rely on fsfreeze/thaw commands disabling/enabling logging
then having other commands check whether logging is disabled to avoid
executing if they aren't safe for running while a filesystem is frozen.

Instead, have an explicit whitelist of fsfreeze-safe commands, and
consolidate logging and command enablement/disablement into a pair
of helper functions: ga_set_frozen()/ga_unset_frozen()

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-04-30 08:42:10 -05:00
Michael Roth
9e8aded432 qemu-ga: improve recovery options for fsfreeze
guest-fsfreeze-thaw relies on state information obtained from
guest-fsfreeze-freeze to determine what filesystems to unfreeze.
This is unreliable due to the fact that that state does not account
for FIFREEZE being issued by other processes, or previous instances
of qemu-ga. This means in certain situations we cannot thaw
filesystems even with a responsive qemu-ga instance at our disposal.

This patch allows guest-fsfreeze-thaw to be issued unconditionally.
It also adds some additional logic to allow us to thaw filesystems
regardless of how many times the filesystem's "frozen" refcount has
been incremented by any guest processes.

Also, guest-fsfreeze-freeze now operates atomically: on success all
freezable filesystems are frozen, and on error all filesystems are
thawed. The ambiguous "GUEST_FSFREEZE_STATUS_ERROR" state is no
longer entered.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-04-30 08:41:40 -05:00
Michael Roth
d35d4cb517 qemu-ga: generate missing stubs for fsfreeze
When linux-specific commands (including guest-fsfreeze-*) were consolidated
under defined(__linux__), we forgot to account for the case where
defined(__linux__) && !defined(FIFREEZE). As a result stubs are no longer
being generated on linux hosts that don't have FIFREEZE support. Fix
this.

Tested-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2012-04-19 10:42:59 -05:00
Michael Roth
e72c3f2ed9 qemu-ga: fix bsd build, and re-org linux-specific implementations 2012-03-25 14:34:20 -05:00
Michael Roth
3cf0bed836 qemu-ga: add guest-sync-delimited
guest-sync leaves it as an exercise to the user as to how to reliably
obtain the response to guest-sync if the client had previously read in a
partial response (due qemu-ga previously being restarted mid-"sentence"
due to reboot, forced restart, etc).

qemu-ga handles this situation on its end by having a client precede
their guest-sync request with a 0xFF byte (invalid UTF-8), which
qemu-ga/QEMU JSON parsers will treat as a flush event. Thus we can
reliably flush the qemu-ga parser state in preparation for receiving
the guest-sync request.

guest-sync-delimited provides the same functionality for a client: when
a guest-sync-delimited is issued, qemu-ga will precede it's response
with a 0xFF byte that the client can use as an indicator to flush its
buffer/parser state in preparation for reliably receiving the
guest-sync-delimited response.

It is also useful as an optimization for clients, since, after issuing a
guest-sync-delimited, clients can safely discard all stale data read
from the channel until the 0xFF is found.

More information available on the wiki:

http://wiki.qemu.org/Features/QAPI/GuestAgent#QEMU_Guest_Agent_Protocol

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-03-12 15:09:23 -05:00