Previous patch of this series proposed a fix to virDirCreate, so that parent
process reports an error if child process failed its task.
However our logic still permits the child to exit with negative errno followed
by a check of the status on the parent side using WEXITSTATUS which, being
POSIX compliant, takes the lower 8 bits of the exit code and returns is to
the caller. However, by taking 8 bits from a negative exit code
(two's complement) the status value we read and append to stream is
'2^8 - abs(original exit code)' which doesn't quite reflect the real cause when
compared to the meaning of errno values.

Only set directory permissions at pool build time, if:

- User explicitly requested a mode via the XML
- The directory needs to be created
- We need to do the crazy NFS root-squash workaround

This allows qemu:///session to call build on an existing directory
like /tmp.

The only two virDirCreate callers already use it

I screwed this up in the previous (post 1.2.16) commits

Currently we try to chown any directory passed to virDirCreate,
even if the user didn't request any explicit owner/group via the
pool/vol XML.

This causes issues with qemu:///session: try to build a pool of
a root owned directory like /tmp, and it fails trying to chown the
directory to the session user. Instead it should just leave things
as they are, unless the user requests changing permissions via
the pool XML.

Similarly this is annoying if creating a storage pool via system
libvirtd of an existing directory in user $HOME, it's now owned
by root.

The virDirCreate function is pretty convoluted, since it needs to
fork off in certain specific cases. Try to document that, to make
it clear where exactly we are changing behavior.

The current code attempts to handle this, but it only catches mkdir
failing with EEXIST. However if say trying to build /tmp for an
unprivileged qemu:///session, mkdir will fail with EPERM.

Rather than catch any errors, just don't attempt mkdir if the directory
already exists.

rfc3986 states that the separator in URI path is a single slash.
Multiple slashes may potentially lead to different resources and thus we
should not remove them.

Not all files we want to find using virFileFindResource{,Full} are
generated when libvirt is built, some of them (such as RNG schemas) are
distributed with sources. The current API was not able to find source
files if libvirt was built in VPATH.

Both RNG schemas and cpu_map.xml are distributed in source tarball.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Rather than have a dummy waitpid loop and return of the failure status
from recvfd, adjust the logic to save the recvfd error & fd and then
in priority order:

- if waitpid failed, use that errno value
- waitpid succeeded, but if the child exited abnormally, report failure
(use EACCES to report as return failure, since either EACCES or EPERM is
what caused us to fall into the fork+setuid path)
- waitpid succeeded, but if the child reported non-zero status, report
failure (use the errno value that the child encoded into exit status)
- waitpid succeeded, but if recvfd failed, report recvfd_errno
- waitpid and recvfd succeeded, use the fd

NOTE: Original logic to retry the open and force owner mode was
"documented" as only being attempted if we had already tried opening
with the fork+setuid, but checked flags vs. VIR_FILE_OPEN_NOFORK which
is counter to how we would get to that point. So that code was removed.

Some code paths have special logic depending on the page size
reported by sysconf, which in turn affects the test results.
We must mock this so tests always have a consistent page size.

A gnulib change (commit id 'beae0bdc') causes ENOTCONN to be returned
from recvfd which causes us to fall into the throwaway waitpid() call
and return ENOTCONN to the caller, this then gets displayed during
a 'virsh save' when using a root squashed NFS environment that's trying
to save the file as something other than root:root.

This patch will add the additional check for ENOTCONN to force the code
into the waitpid loop looking for the actual status from the _exit()'d
child fork.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Remove the resize flag and use the same code path for all callers.
This flag was added by commit 18f03166 to allow virStorageFileResize
use 'safezero' while preserving the behavior.

Explicitly return -2 when a fallback to a different method should
be done, to make the code path more obvious.

Fail immediately when ftruncate fails in the mmap method,
as we did before commit 18f03166.

* src/util/virfile.c (safezero_mmap): Fix missing semicolon.
Signed-off-by: NEric Blake <eblake@redhat.com>

When any of the functions modified in commit 214c687b took false branch,
the function itself used none of its parameters resulting in "unused
parameter" error.  Rewriting these functions to the stubs we use
elsewhere should fix the problem.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Currently virStorageFileResize() function uses build conditionals to
choose either the posix_fallocate() or syscall(SYS_fallocate) with no
fallback in order to preallocate the space in the newly resized file.

Since the safezero code has a similar set of conditionals modify the
resize and safezero code in order to allow the resize logic to make use
of safezero to unify the look/feel of the code paths.

Add a new boolean (resize) to safezero() to make the optional decision
whether to try syscall(SYS_fallocate) if the posix_fallocate fails because
HAVE_POSIX_FALLOCATE is not defined (eg, return -1 and errno == 0).

Create a local safezero_sys_fallocate in order to handle the resize
code paths that support that.  If not present, the set errno = ENOSYS
in order to allow the caller to handle the failure scenarios.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Currently build conditionals decide which of two safezero() functions
should be built - either the posix_fallocate() or mmap() with a fallback
to a slower safewrite() algorithm in order to preallocate space in a raw file.

This patch will refactor safezero to utilize static functions for either
posix_fallocate or mmap/safewrite. The build conditional still exist, but
are only for shorter sections of code.

The posix_fallocate path will make use of the ret/errno setting to contain
the logic for safezero to decide whether it needs to fallback to other
algorithms. A return of -1 with errno not changed will indicate the conditional
is not present; otherwise, a return of -1 with errno change indicates the
call was made and it failed (no functional difference to current algorithm).

The mmap/safewrite option changes only slightly to handle the ftruncate
failure for mmap. That is, previously if the ftruncate failed, there was
no fallback to the slow safewrite option.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

C guarantees that static variables are zero-initialized.  Some older
compilers (and also gcc -fno-zero-initialized-in-bss) create larger
binaries if you explicitly zero-initialize a static variable.

* src/libvirt.c: Fix initialization.
* src/util/viralloc.c: Likewise.
* src/util/virdbus.c: Likewise.
* src/util/virevent.c: Likewise.
* src/util/virfile.c (safezero): Likewise.
* src/util/virlog.c: Likewise.
* src/util/virnetlink.c: Likewise.
* src/util/virthread.h (VIR_ONCE_GLOBAL_INIT): Likewise.
* src/util/virprocess.c (virProcessGetStartTime): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

and tweak the code to avoid using it.

With the virGetGroupList() change in place - Coverity further complains
that if we fail to virFork(), the groups will be leaked - which aha seems
to be the case. Adjust the logic to save off the -errno, free the groups,
and then return the value we saved
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Adjust the parentheses in/for the waitpid loops; otherwise, Coverity
points out:

(1) Event assignment:   Assigning: "waitret" = "waitpid(pid, &status, 0) == -1"
(2) Event between:      At condition "waitret == -1", the value of "waitret"
                        must be between 0 and 1.
(3) Event dead_error_condition:     The condition "waitret == -1" cannot
                        be true.
(4) Event dead_error_begin:     Execution cannot reach this statement:
                        "ret = -*__errno_location();".
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Our style overwhelmingly uses hanging braces (the open brace
hangs at the end of the compound condition, rather than on
its own line), with the primary exception of the top level function
body.  Fix the few remaining outliers, before adding a syntax
check in a later patch.

* src/interface/interface_backend_netcf.c (netcfStateReload)
(netcfInterfaceClose, netcf_to_vir_err): Correct use of { in
compound statement.
* src/conf/domain_conf.c (virDomainHostdevDefFormatSubsys)
(virDomainHostdevDefFormatCaps): Likewise.
* src/network/bridge_driver.c (networkAllocateActualDevice):
Likewise.
* src/util/virfile.c (virBuildPathInternal): Likewise.
* src/util/virnetdev.c (virNetDevGetVirtualFunctions): Likewise.
* src/util/virnetdevmacvlan.c
(virNetDevMacVLanVPortProfileCallback): Likewise.
* src/util/virtypedparam.c (virTypedParameterAssign): Likewise.
* src/util/virutil.c (virGetWin32DirectoryRoot)
(virFileWaitForDevices): Likewise.
* src/vbox/vbox_common.c (vboxDumpNetwork): Likewise.
* tests/seclabeltest.c (main): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Otherwise we fail like

  libvirt version: 1.2.7, package: 6 (root 2014-08-08-16:09:22 bogon)
  virAuditOpen:62 : Unable to initialize audit layer: Protocol not supported
  virFileGetDefaultHugepageSize:2958 : internal error: Unable to parse /proc/meminfo
  virStateInitialize:749 : Initialization of QEMU state driver failed: internal error: Unable to parse /proc/meminfo
  daemonRunStateInit:922 : Driver state initialization failed

if the data can't be determined.

Reference: http://bugs.debian.org/757609

Since commit be0782e1 we are parsing /proc/meminfo to find out the
default huge page size. However, if the host we are running at does
not support any huge pages (e.g. CONFIG_HUGETLB_PAGE is turned off),
we will not successfully parse the meminfo file and hence the whole
qemu driver init process fails. Moreover, the default huge page size
is needed if and only if there's at least one hugetlbfs mount point.
So the fix consists of moving the virFileGetDefaultHugepageSize
function call after the first hugetlbfs mount point is found.

With this fix, we fail to start with one or more hugetlbfs mounts and
malformed meminfo file, but that's expected (how can one mount
hugetlbfs without kernel supporting huge pages?). Workaround in that
case is to umount all the hugetlbfs mounts.
Reported-by: NJim Fehlig <jfehlig@suse.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

This should iterate over mount tab and search for hugetlbfs among with
looking for the default value of huge pages.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Just like virFileReadAll, but returns -errno instead
of reporting errors. Useful for ignoring some errors.

In "src/util/" there are many enumeration (enum) declarations.
Sometimes, it's better using a typedef for variable types,
function types and other usages. Other enumeration will be
changed to typedef's in the future.
Signed-off-by: NJulio Faracco <jcfaracco@gmail.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Now that all clients have been adjusted, ensure that no future
misuse of readdir is introduced into the code base.

* cfg.mk (sc_prohibit_readdir): New rule.
* src/util/virfile.c (virDirRead): Exempt the wrapper.
Signed-off-by: NEric Blake <eblake@redhat.com>

In making the conversion to the new API, I fixed a couple bugs:
virSCSIDeviceGetSgName would leak memory if a directory
unexpectedly contained multiple entries;
virNetDevTapGetRealDeviceName could report a spurious error
from a stale errno inherited before starting the readdir search.

The decision on whether to store the result of virDirRead into
a variable is based on whether the end of the loop falls through
to cleanup code automatically.  In some cases, we have loops that
are documented to return NULL on failure, and which raise an
error on most failure paths but not in the case where the directory
was unexpectedly empty; it may be worth a followup patch to
explicitly report an error if readdir was successful but the
directory was empty, so that a NULL return always has an error set.

* src/util/vircgroup.c (virCgroupRemoveRecursively): Use new
interface.
(virCgroupKillRecursiveInternal, virCgroupSetOwner): Report
readdir failures.
* src/util/virfile.c (virFileLoopDeviceOpenSearch)
(virFileNBDDeviceFindUnused, virFileDeleteTree): Use new
interface.
* src/util/virnetdevtap.c (virNetDevTapGetRealDeviceName):
Properly check readdir errors.
* src/util/virpci.c (virPCIDeviceIterDevices)
(virPCIDeviceFileIterate, virPCIGetNetName): Report readdir
failures.
(virPCIDeviceAddressIOMMUGroupIterate): Use new interface.
* src/util/virscsi.c (virSCSIDeviceGetSgName): Report readdir
failures, and avoid memory leak.
(virSCSIDeviceGetDevName): Report readdir failures.
* src/util/virusb.c (virUSBDeviceSearch): Report readdir
failures.
* src/util/virutil.c (virGetFCHostNameByWWN)
(virFindFCHostCapableVport): Report readdir failures.
Signed-off-by: NEric Blake <eblake@redhat.com>

Introduce a wrapper for readdir. This helps us make sure that we always
set errno before calling readdir and it will make sure errors are
properly logged.
Signed-off-by: NNatanael Copa <ncopa@alpinelinux.org>
Signed-off-by: NEric Blake <eblake@redhat.com>

Instead of hardcoding LIBEXECDIR as the location of the libvirt_iohelper
binary, use virFileFindResource to optionally find it in the current
build directory.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add virFileFindResource which will try to locate files
in the local build tree if the calling binary (eg libvirtd or
test suite) is being run from the build tree. The corresponding
virFileActivateDirOverride should be called at startup passing
in argv[0]. This will be examined for evidence of libtool magic
binary prefix / sub-directory in order to activate the override.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Fix minor typos in source comments
Signed-off-by: NEric Blake <eblake@redhat.com>

When checking if two filenames point to the same inode (whether
by hardlink or symlink), sometimes one of the names might be
relative.  This convenience function makes it easier to check.

* src/util/virfile.h (virFileRelLinkPointsTo): New prototype.
* src/util/virfile.c (virFileRelLinkPointsTo): New function.
* src/libvirt_private.syms (virfile.h): Export it.
* src/xen/xm_internal.c (xenXMDomainGetAutostart): Use it.
Signed-off-by: NEric Blake <eblake@redhat.com>

The only remaining reason that virt-login-shell was trying to
link against virstoragefile was because of a call to
virStorageFileFormatTypeToString when spawning a qemu-nbd
process - but setuid processes shouldn't be spawning qemu-nbd.

* src/util/virfile.c (virFileLoopDeviceAssociate)
(virFileNBDDeviceAssociate): Cripple in setuid builds.
* src/Makefile.am (libvirt_setuid_rpc_client_la_SOURCES):
Drop virstoragefile from the list.
Signed-off-by: NEric Blake <eblake@redhat.com>

The code in virstoragefile.c is getting more complex as I
consolidate backing chain handling code.  But for the setuid
virt-login-shell, we don't need to crawl backing chains.  It's
easier to audit things for setuid security if there are fewer
files involved, so this patch moves the one function that
virFileOpen() was actually relying on to also live in virfile.c.

* src/util/virstoragefile.c (virStorageFileIsSharedFS)
(virStorageFileIsSharedFSType): Move...
* src/util/virfile.c (virFileIsSharedFS, virFileIsSharedFSType):
...to here, and rename.
(virFileOpenAs): Update caller.
* src/security/security_selinux.c
(virSecuritySELinuxSetFileconHelper)
(virSecuritySELinuxSetSecurityAllLabel)
(virSecuritySELinuxRestoreSecurityImageLabelInt): Likewise.
* src/security/security_dac.c
(virSecurityDACRestoreSecurityImageLabelInt): Likewise.
* src/qemu/qemu_driver.c (qemuOpenFileAs): Likewise.
* src/qemu/qemu_migration.c (qemuMigrationIsSafe): Likewise.
* src/util/virstoragefile.h: Adjust declarations.
* src/util/virfile.h: Likewise.
* src/libvirt_private.syms (virfile.h, virstoragefile.h): Move
symbols as appropriate.
Signed-off-by: NEric Blake <eblake@redhat.com>

Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Our current pidfile acquire APis (virPidFileAcquire) simply return -1 upon
failure to acquire a lock. This patch adds a parameter 'bool waitForLock'
which instructs the APIs if we want to make it block and wait for the lock
or not.

The old semantics of virFork() violates the priciple of good
usability: it requires the caller to check the pid argument
after use, *even when virFork returned -1*, in order to properly
abort a child process that failed setup done immediately after
fork() - that is, the caller must call _exit() in the child.
While uses in virfile.c did this correctly, uses in 'virsh
lxc-enter-namespace' and 'virt-login-shell' would happily return
from the calling function in both the child and the parent,
leading to very confusing results. [Thankfully, I found the
problem by inspection, and can't actually trigger the double
return on error without an LD_PRELOAD library.]

It is much better if the semantics of virFork are impossible
to abuse.  Looking at virFork(), the parent could only ever
return -1 with a non-negative pid if it misused pthread_sigmask,
but this never happens.  Up until this patch series, the child
could return -1 with non-negative pid if it fails to set up
signals correctly, but we recently fixed that to make the child
call _exit() at that point instead of forcing the caller to do
it.  Thus, the return value and contents of the pid argument are
now redundant (a -1 return now happens only for failure to fork,
a child 0 return only happens for a successful 0 pid, and a
parent 0 return only happens for a successful non-zero pid),
so we might as well return the pid directly rather than an
integer of whether it succeeded or failed; this is also good
from the interface design perspective as users are already
familiar with fork() semantics.

One last change in this patch: before returning the pid directly,
I found cases where using virProcessWait unconditionally on a
cleanup path of a virFork's -1 pid return would be nicer if there
were a way to avoid it overwriting an earlier message.  While
such paths are a bit harder to come by with my change to a direct
pid return, I decided to keep the virProcessWait change in this
patch.

* src/util/vircommand.h (virFork): Change signature.
* src/util/vircommand.c (virFork): Guarantee that child will only
return on success, to simplify callers.  Return pid rather than
status, now that the situations are always the same.
(virExec): Adjust caller, also avoid open-coding process death.
* src/util/virprocess.c (virProcessWait): Tweak semantics when pid
is -1.
(virProcessRunInMountNamespace): Adjust caller.
* src/util/virfile.c (virFileAccessibleAs, virFileOpenForked)
(virDirCreate): Likewise.
* tools/virt-login-shell.c (main): Likewise.
* tools/virsh-domain.c (cmdLxcEnterNamespace): Likewise.
* tests/commandtest.c (test23): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>