Commit Graph

1263 Commits

Author SHA1 Message Date
John Ferlan
277aaeeebf vircommand: Remove unnecessary sa_assert
Changes from commit '3178df9a' removed the need for the sa_assert(infd).
2013-02-16 07:44:35 -05:00
Eric Blake
d1333dd0fb storage: don't follow backing chain symlinks too eagerly
If you have a qcow2 file /path1/to/file pointed to by symlink
/path2/symlink, and pass qemu /path2/symlink, then qemu treats
a relative backing file in the qcow2 metadata as being relative
to /path2, not /path1/to.  Yes, this means that it is possible
to create a qcow2 file where the choice of WHICH directory and
symlink you access its contents from will then determine WHICH
backing file (if any) you actually find; the results can be
rather screwy, but we have to match what qemu does.

Libvirt and qemu default to creating absolute backing file
names, so most users don't hit this.  But at least VDSM uses
symlinks and relative backing names alongside the
--reuse-external flags to libvirt snapshot operations, with the
result that libvirt was failing to follow the intended chain of
backing files, and then backing files were not granted the
necessary sVirt permissions to be opened by qemu.

See https://bugzilla.redhat.com/show_bug.cgi?id=903248 for
more gory details.  This fixes a regression introduced in
commit 8250783.

I tested this patch by creating the following chain:

ls /home/eblake/Downloads/Fedora.iso # raw file for base
cd /var/lib/libvirt/images
qemu-img create -f qcow2 \
  -obacking_file=/home/eblake/Downloads/Fedora.iso,backing_fmt=raw one
mkdir sub
cd sub
ln -s ../one onelink
qemu-img create -f qcow2 \
  -obacking_file=../sub/onelink,backing_fmt=qcow2 two
mv two ..
ln -s ../two twolink
qemu-img create -f qcow2 \
  -obacking_file=../sub/twolink,backing_fmt=qcow2 three
mv three ..
ln -s ../three threelink

then pointing my domain at /var/lib/libvirt/images/sub/threelink.
Prior to this patch, I got complaints about missing backing
files; afterwards, I was able to verify that the backing chain
(and hence DAC and SELinux relabels) of the entire chain worked.

* src/util/virstoragefile.h (_virStorageFileMetadata): Add
directory member.
* src/util/virstoragefile.c (absolutePathFromBaseFile): Drop,
replaced by...
(virFindBackingFile): ...better function.
(virStorageFileGetMetadataInternal): Add an argument.
(virStorageFileGetMetadataFromFD, virStorageFileChainLookup)
(virStorageFileGetMetadata): Update callers.
2013-02-15 16:07:01 -07:00
Eric Blake
2485f92153 storage: refactor metadata lookup
Prior to this patch, we had the callchains:
external users
  \-> virStorageFileGetMetadataFromFD
      \-> virStorageFileGetMetadataFromBuf
virStorageFileGetMetadataRecurse
  \-> virStorageFileGetMetadataFromFD
      \-> virStorageFileGetMetadataFromBuf

However, a future patch wants to add an additional parameter to
the bottom of the chain, for use by virStorageFileGetMetadataRecurse,
without affecting existing external callers.  Since there is only a
single caller of the internal function, we can repurpose it to fit
our needs, with this patch giving us:

external users
  \-> virStorageFileGetMetadataFromFD
      \-> virStorageFileGetMetadataInternal
virStorageFileGetMetadataRecurse /
  \-> virStorageFileGetMetadataInternal

* src/util/virstoragefile.c (virStorageFileGetMetadataFromFD):
Move most of the guts...
(virStorageFileGetMetadataFromBuf): ...here, and rename...
(virStorageFileGetMetadataInternal): ...to this.
(virStorageFileGetMetadataRecurse): Use internal helper.
2013-02-15 16:07:00 -07:00
Eric Blake
b7df4f92d6 storage: prepare for refactoring
virStorageFileGetMetadataFromFD is the only caller of
virStorageFileGetMetadataFromBuf; and it doesn't care about the
difference between a return of 0 (total success) or 1
(metadata was inconsistent, but pointer was populated as best
as possible); only about a return of -1 (could not read metadata
or out of memory).  Changing the return type, and normalizing
the variable names used, will make merging the functions easier
in the next commit.

* src/util/virstoragefile.c (virStorageFileGetMetadataFromBuf):
Change return value, and rename some variables.
(virStorageFileGetMetadataFromFD): Rename some variables.
2013-02-15 16:07:00 -07:00
Eric Blake
5e4946d4d9 storage: rearrange functions
No semantic change; done so the next patch doesn't need a forward
declaration of a static function.

* src/util/virstoragefile.c (virStorageFileProbeFormatFromBuf):
Hoist earlier.
2013-02-15 16:07:00 -07:00
Eric Blake
660db5bf72 build: fix mingw build
Commits 2025356 and ba72cb12 introduced typos.

* src/util/virpci.c (virPCIIsVirtualFunction) [!__linux__]: Fix
function name.
* src/util/virutil.c (virGetDeviceID): Fix attribute spelling.
2013-02-15 15:05:25 -07:00
Eric Blake
ec2cc0f860 build: fix vircommand build on mingw
CC       libvirt_util_la-vircommand.lo
../../src/util/vircommand.c:2358:1: error: 'virCommandHandshakeChild' defined but not used [-Werror=unused-function]

The function is only implemented inside #ifndef WIN32.

* src/util/vircommand.c (virCommandHandshakeChild): Hoist earlier,
so that win32 build doesn't hit an unused forward declaration.
2013-02-15 13:16:46 -07:00
Laine Stump
7a2e845a86 util: maintain caps when running command with uid != 0
virCommand was previously calling virSetUIDGID() to change the uid and
gid of the child process, then separately calling
virSetCapabilities(). This did not work if the desired uid was != 0,
since a setuid to anything other than 0 normally clears all
capabilities bits.

The solution is to use the new virSetUIDGIDWithCaps(), sending it the
uid, gid, and capabilities bits. This will get the new process setup
properly.

Since the static functions virSetCapabilities() and
virClearCapabilities are no longer called, they have been removed.

NOTE: When combined with "filecap $path-to-qemu sys_rawio", this patch
will make CAP_SYS_RAWIO (which is required for passthrough of generic
scsi commands to a guest - see commits e8daeeb, 177db08, 397e6a7, and
74e0349) be retained by qemu when necessary. Apparently that
capability has been broken for non-root qemu ever since it was
originally added.
2013-02-13 16:11:16 -05:00
Laine Stump
e11451f42e util: virSetUIDGIDWithCaps - change uid while keeping caps
Normally when a process' uid is changed to non-0, all the capabilities
bits are cleared, even those explicitly set with calls to
capng_update()/capng_apply() made immediately before setuid. And
*after* the process' uid has been changed, it no longer has the
necessary privileges to add capabilities back to the process.

In order to set a non-0 uid while still maintaining any capabilities
bits, it is necessary to either call capng_change_id() (which
unfortunately doesn't currently call initgroups to setup auxiliary
group membership), or to perform the small amount of calisthenics
contained in the new utility function virSetUIDGIDWithCaps().

Another very important difference between the capabilities
setting/clearing in virSetUIDGIDWithCaps() and virCommand's
virSetCapabilities() (which it will replace in the next patch) is that
the new function properly clears the capabilities bounding set, so it
will not be possible for a child process to set any new
capabilities.

A short description of what is done by virSetUIDGIDWithCaps():

1) clear all capabilities then set all those desired by the caller (in
capBits) plus CAP_SETGID, CAP_SETUID, and CAP_SETPCAP (which is needed
to change the capabilities bounding set).

2) call prctl(), telling it that we want to maintain current
capabilities across an upcoming setuid().

3) switch to the new uid/gid

4) again call prctl(), telling it we will no longer want capabilities
maintained if this process does another setuid().

5) clear the capabilities that we added to allow us to
setuid/setgid/change the bounding set (unless they were also requested
by the caller via the virCommand API).

Because the modification/maintaining of capabilities is intermingled
with setting the uid, this is necessarily done in a single function,
rather than having two independent functions.

Note that, due to the way that effective capabilities are computed (at
time of execve) for a process that has uid != 0, the *file*
capabilities of the binary being executed must also have the desired
capabilities bit(s) set (see "man 7 capabilities"). This can be done
with the "filecap" command. (e.g. "filecap /usr/bin/qemu-kvm sys_rawio").
2013-02-13 16:11:16 -05:00
Laine Stump
c0e3e685cd util: drop capabilities immediately after changing uid/gid of child
This is an interim measure to make sure everything still works in this
order. The next step will be to perform capabilities drop and
setuid/gid as a single operation (which is the only way to keep any
capabilities when switching to a non-root uid).
2013-02-13 16:11:16 -05:00
Laine Stump
6c3f3d0d89 util: add security label setting to virCommand
virCommand gets two new APIs: virCommandSetSELinuxLabel() and
virCommandSetAppArmorProfile(), which both save a copy of a
null-terminated string in the virCommand. During virCommandRun, if the
string is non-NULL and we've been compiled with AppArmor and/or
SELinux security driver support, the appropriate security library
function is called for the child process, using the string that was
previously set. In the case of SELinux, setexeccon_raw() is called,
and for AppArmor, aa_change_profile() is called.

This functionality has been added so that users of virCommand can use
the upcoming virSecurityManagerSetChildProcessLabel() prior to running
a child process, rather than needing to setup a hook function to be
called (and in turn call virSecurityManagerSetProcessLabel()) *during*
the setup of the child process.
2013-02-13 16:11:15 -05:00
Laine Stump
f506a4c115 util: make virSetUIDGID a NOP only when uid or gid is -1
Rather than treating uid:gid of 0:0 as a NOP, we blindly pass that
through to the lower layers. However, we *do* check for a requested
value of "-1" to mean "don't change this setting". setregid() and
setreuid() already interpret -1 as a NOP, so this is just an
optimization, but we are also calling getpwuid_r and initgroups, and
it's unclear what the former would do with a uid of -1.
2013-02-13 16:11:15 -05:00
Laine Stump
417182b072 util: add virCommandSetUID and virCommandSetGID
If a uid and/or gid is specified for a command, it will be set just
after the user-supplied post-fork "hook" function is called.

The intent is that this can replace user hook functions that set
uid/gid. This moves the setting of uid/gid and dropping of
capabilities closer to each other, which is important since the two
should really be done at the same time (libcapng provides a single
function that does both, which we will be unable to use, but want to
mimic as closely as possible).
2013-02-13 16:11:15 -05:00
Laine Stump
ad5cb11be6 util: refactor virCommandHook into virExec and virCommandHandshakeChild 2013-02-13 16:11:15 -05:00
Laine Stump
5f2ce53984 util: eliminate extra args from virExec
All args except "cmd" in the call to virExec are now redundant, since
they can all be found in cmd, so remove the args and reference the
data directly in cmd. One exception to this is that "infd" was being
modified within virExec, and modifying the original in cmd caused make
check failures, so cmd->infd is copied to a local, and the local is
used during virExec().
2013-02-13 16:11:15 -05:00
Laine Stump
b6decc57b1 util: eliminate generic hook from virExecWithHook
virExecWithHook is only called from one place, so it always has the
same "hook" function (virHookCommand), and the data sent to that
function is always a virCommandPtr, so eliminate the function and
generic data from the arglist, and replace it with "virCommandPtr
cmd". The call to (hook)(data) is replaced with
"virHookCommand(cmd)". Finally, virExecWithHook is renamed to virExec.

Indentation has been updated only for code that will remain after the
next patch, which will remove all other args to virExec (since they
are now redundant, as they're all members of virCommandPtr).
2013-02-13 16:11:15 -05:00
Michal Privoznik
3178df9afa virCommand: Don't misuse the eventloop for async IO
Currently, if a command wants to do asynchronous IO, a callback
is registered in the libvirtd eventloop to handle writes and
reads. However, there's a race in virCommandWait. The eventloop
may already be executing the callback, while virCommandWait is
mangling internal state of virCommand. To deal with it, we need
to either introduce locking or spawn a separate thread where we
poll() on stdio from child. The former, however, requires to
unlock all mutexes held, as the event loop may execute other
callbacks which tries to lock one of the mutexes, deadlock and
thus never wake us up. So it's safer to spawn a separate thread.
2013-02-13 09:54:19 +01:00
Eric Blake
731ad69240 util: use new virendian.h macros
This makes code easier to read, by avoiding lines longer than
80 columns and removing the repetition from the callers.

* src/util/virstoragefile.c (qedGetHeaderUL, qedGetHeaderULL):
Delete in favor of more generic macros.
(qcow2GetBackingStoreFormat, qcowXGetBackingStore)
(qedGetBackingStore, virStorageFileMatchesVersion)
(virStorageFileGetMetadataInternal): Use new macros.
* src/cpu/cpu_x86.c (x86VendorLoad): Likewise.
2013-02-12 09:00:17 -07:00
Eric Blake
c6f1060ca7 util: add virendian.h macros
We have several cases where we need to read endian-dependent
data regardless of host endianness; rather than open-coding
these call sites, it will be nicer to funnel things through
a macro.

The virendian.h file can be expanded to add writer functions,
and/or 16-bit access patterns, if needed.  Also, if we need
to turn things into a function to avoid multiple evaluations
of buf, that can be done later.  But for now, a macro worked.

* src/util/virendian.h: New file.
* src/Makefile.am (UTIL_SOURCES): Ship it.
* tests/virendiantest.c: New test.
* tests/Makefile.am (test_programs, virendiantest_SOURCES): Run
the test.
* .gitignore: Ignore built file.
2013-02-12 09:00:15 -07:00
Natanael Copa
f3531a040c util: refactor iptables command construction into multiple steps
Instead of creating an iptables command in one shot, do it in steps
so we can add conditional options like physdev and protocol.

This removes code duplication while keeping existing behaviour.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Eric Blake <eblake@redhat.com>
2013-02-08 14:19:30 -07:00
Michal Privoznik
0d36f228a4 virCondDestroy: Lose attribute RETURN_CHECK
We are wrapping it in ignore_value() anyway.
2013-02-08 09:12:11 +01:00
Michal Privoznik
4ca6f5089f Drop useless virFileWrapperFdCatchError
We are requesting for stderr catching for all cases in
virFileWrapperFdNew(). There is no need to have a separate
function just to report an error, esp. when we can do it in
virFileWrapperFdClose().
2013-02-08 09:11:51 +01:00
Eric Blake
98fc0137f1 bitmap: add way to find next clear bit
We had an easy way to iterate set bits, but not for iterating
cleared bits.

* src/util/virbitmap.h (virBitmapNextClearBit): New prototype.
* src/util/virbitmap.c (virBitmapNextClearBit): Implement it.
* src/libvirt_private.syms (bitmap.h): Export it.
* tests/virbitmaptest.c (test4): Test it.
2013-02-05 16:23:14 -07:00
Daniel P. Berrange
0f9ef55814 Convert virPCIDeviceList and virUSBDeviceList into virObjectLockable
To allow modifications to the lists to be synchronized, convert
virPCIDeviceList and virUSBDeviceList into virObjectLockable
classes. The locking, however, will not be self-contained. The
users of these classes will have to call virObjectLock/Unlock
in the critical regions.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2013-02-05 19:22:26 +00:00
Daniel P. Berrange
77c3015f9c Rename all USB device functions to have a standard name prefix
Rename all the usbDeviceXXX and usbXXXDevice APIs to have a
fixed virUSBDevice name prefix
2013-02-05 19:22:25 +00:00
Daniel P. Berrange
202535601c Rename all PCI device functions to have a standard name prefix
Rename all the pciDeviceXXX and pciXXXDevice APIs to have a
fixed virPCIDevice name prefix
2013-02-05 19:22:25 +00:00
Michal Privoznik
1f25194ad1 virFileWrapperFd: Switch to new virCommandDoAsyncIO
Commit 34e8f63a32 introduced support for catching errors from
libvirt iohelper. However, at those times there wasn't such fancy
API as virCommandDoAsyncIO(), so everything has to be implemented
on our own. But since we do have the API now, we can use it and
drop our implementation then.
2013-02-05 15:45:21 +01:00
Michal Privoznik
68fb755002 virCommand: Introduce virCommandDoAsyncIO
Currently, if we want to feed stdin, or catch stdout or stderr of a
virCommand we have to use virCommandRun(). When using virCommandRunAsync()
we have to register FD handles by hand. This may lead to code duplication.
Hence, introduce an internal API, which does this automatically within
virCommandRunAsync(). The intended usage looks like this:

    virCommandPtr cmd = virCommandNew*(...);
    char *buf = NULL;

    ...

    virCommandSetOutputBuffer(cmd, &buf);
    virCommandDoAsyncIO(cmd);

    if (virCommandRunAsync(cmd, NULL) < 0)
        goto cleanup;

    ...

    if (virCommandWait(cmd, NULL) < 0)
        goto cleanup;

    /* @buf now contains @cmd's stdout */
    VIR_DEBUG("STDOUT: %s", NULLSTR(buf));

    ...

cleanup:
    VIR_FREE(buf);
    virCommandFree(cmd);

Note, that both stdout and stderr buffers may change until virCommandWait()
returns.
2013-02-05 15:45:21 +01:00
Martin Kletzander
027bf2ea37 Add basic support for VDI images
QEMU is fully capable of handling VDI images and we just refuse to
work with them.  As qemu-img knows and supports this, there should be
no problem with this addition.

This is of course, just basic functionality, without searching for any
backing files, etc.
2013-02-04 23:47:42 +01:00
Martin Kletzander
a0f98229ba Support shifted magic in storage files
Some files have the magic shifted to some offset other than 0, so we
have to support that.  I also cleaned up some lines to be more
readable and added missing magic for iso file format.
2013-02-04 23:46:46 +01:00
Eric Blake
b2aa03b3f7 docs: don't ignore virEvent API
Commit 6094ad7b (0.9.3 release) promoted several functions from
internal to public, but forgot to fix the documentation generator
to provide details about those functions.

For an example of what this fixes, look at:
file:///path/to/libvirt/docs/html/libvirt-libvirt.html#virEventAddHandle
before and after the patch.

* docs/apibuild.py (ignored_functions): Don't ignore functions
that were turned into official API.
* src/util/virevent.c: Fix comments to pass through parser.
2013-02-01 16:01:45 -07:00
John Ferlan
46b1d8cf7a Enforce return check on virAsprintf() calls
Way back when I started making changes for Coverity messages my first set
were to a bunch of CHECKED_RETURN errors.  In particular virAsprintf() had
a few callers that Coverity noted didn't check their return (although some
did check if the buffer being printed to was NULL or not).

It was suggested at the time as a further patch an ATTRIBUTE_RETURN_CHECK
should be added to virAsprintf(), see:

https://www.redhat.com/archives/libvir-list/2013-January/msg00120.html

This patch does that and fixes a few more instances not found by Coverity
that failed the check.
2013-01-30 14:42:22 -07:00
Jiri Denemark
6405713f2a util: Fix mask for 172.16.0.0 private address range
https://bugzilla.redhat.com/show_bug.cgi?id=905708

Only the first 12 bits should be set in the mask for this range. All
addresses between 172.16.0.0 and 172.31.255.255 are private.
2013-01-30 12:01:01 +01:00
Doug Goldstein
1c23ba286f virlog: remove old code comment
Setting the log output prefix to 0 is not supported and in fact results
in the following message:
warning : virLogParseOutputs:1021 : Ignoring invalid log output setting.
2013-01-29 21:29:53 -06:00
John Ferlan
96e8565de6 util: Need to add virCommandFree() 2013-01-24 12:37:30 +01:00
Peter Krempa
4004977fbf util: Fix docs for virBitmapParse
This patch changes the name of the @sep argument to @terminator and
clarifies it's usage. This patch also explicitly documents that
whitespace can't be used as @terminator as it is skipped multiple times
in the implementation.
2013-01-23 16:21:10 +01:00
Eric Blake
682c79c4f5 build: allow virObject to have no parent
When building with static analysis enabled, we turn on attribute
nonnull checking.  However, this caused the build to fail with:

../../src/util/virobject.c: In function 'virObjectOnceInit':
../../src/util/virobject.c:55:40: error: null argument where non-null required (argument 1) [-Werror=nonnull]

Creation of the virObject class is the one instance where the
parent class is allowed to be NULL.  Making things conditional
will let us keep static analysis checking for all other .c file
callers, without breaking the build on this one exception.

* src/util/virobject.c: Define witness.
* src/util/virobject.h (virClassNew): Use it to force most callers
to pass non-null parameter.
2013-01-22 13:45:38 -07:00
John Ferlan
c9a85af319 viralloc: Adjust definition of VIR_FREE() for Coverity
The Coverity static analyzer was generating many false positives for the
unary operation inside the VIR_FREE() definition as it was trying to evaluate
the else portion of the "?:" even though the if portion was (1).

Signed-off-by: Eric Blake <eblake@redhat.com>
2013-01-22 10:19:43 -07:00
John Ferlan
50adf8271d virfile: Need to initialize 'looppath'
It was possible to call VIR_FREE in cleanup prior to initialization.
2013-01-22 17:29:25 +01:00
John Ferlan
ac5cb26a32 virnetdev: Need to initialize 'pciConfigAddr'
It was possible to call VIR_FREE in cleanup prior to initialization
2013-01-22 17:29:25 +01:00
John Ferlan
e786b57889 util: Need to check child JSON allocation before use 2013-01-22 14:34:12 +01:00
Michal Privoznik
074b6d45b0 safe{read,write}: Document usage with nonblocking FD
Currently, whenever somebody calls saferead() on nonblocking FD
(safewrite() is totally interchangeable for purpose of this message)
he might get wrong return value. For instance, in the first iteration
some data is read. The number of bytes read is stored into local
variable 'nread'. However, in next iterations we can get -1 from
read() with errno == EAGAIN, in which case the -1 is returned despite
fact some data has already been read. So the caller gets confused.
Bare read() should be used for nonblocking FD.
2013-01-21 20:18:28 +01:00
Jiri Denemark
de78bf604c Introduce virTypedParamsClear public API
The function is just a renamed public version of former
virTypedParameterArrayClear.
2013-01-18 15:04:00 +01:00
Jiri Denemark
54dd75fd97 Add virTypedParams* APIs
Working with virTypedParameters in clients written in C is ugly and
requires all clients to duplicate the same code. This set of APIs makes
this code for manipulating with virTypedParameters integral part of
libvirt so that all clients may benefit from it.
2013-01-18 15:03:58 +01:00
Eric Blake
f403bdc189 build: fix build on BSD
A build on FreeBSD failed with:
util/virportallocator.c:108: error: storage size of 'addr' isn't known
util/virportallocator.c:123: error: 'INADDR_ANY' undeclared (first use in this function)

It turns out that while POSIX allows sockaddr_in to leak in through
<arpa/inet.h> (the way Linux does it), it is not mandatory, and
conforming applications are required to get it through <netinet/in.h>.

* src/util/virportallocator.c: Include header for struct
sockaddr_in.
* tests/virportallocatortest.c: Likewise.
2013-01-17 16:39:10 -07:00
John Ferlan
0cff3554f3 virobject: Remove the bogus ! from call to virObjectInitialize() 2013-01-17 23:46:36 +01:00
Daniel P. Berrange
55599102b4 Followup fix for integer wraparound in port allocator
Change iterator variable datatype to int
2013-01-17 19:15:57 +00:00
Daniel P. Berrange
da5a8aee2b Avoid integer wrap on remotePortMax in QEMU driver
The QEMU driver default max port is 65535, but it then increments
this by 1 to 65536. This maps to 0 in an unsigned short :-( This
was apparently done so that for() loops could use "< max" instead
of "<= max". Remove this insanity and just make the loop do the
right thing.
2013-01-17 13:52:33 +00:00
Hu Tao
ad9e110cae include virterror_internal.h in threads.h
required by VIR_ONCE_GLOBAL_INIT using virSetError.
2013-01-16 17:30:22 -07:00
Hu Tao
dfa88e6455 include util.h in cgroup.h
required by VIR_ENUM_DECL.
2013-01-16 17:23:58 -07:00