In an NFS root-squashed environment the 'vol-delete' command will fail to
'unlink' the target volume since it was created under a different uid:gid.

This code continues the concepts introduced in virFileOpenForked and
virDirCreate[NoFork] with respect to running the unlink command under
the uid/gid of the child. Unlike the other two, don't retry on EACCES
(that's why we're here doing this now).

(cherry picked from commit 35847860)

The only two virDirCreate callers already use it

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.

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>

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>

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>

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>

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 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>

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.

Add a helper function which takes a file path and ensures
that all directory components leading up to the file exist.
IOW, it strips the filename part of the path and passes
the result to virFileMakePath.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Move the code for lxcContainerGetSubtree into the virfile
module creating 2 new functions

  int virFileGetMountSubtree(const char *mtabpath,
                             const char *prefix,
                             char ***mountsret,
                             size_t *nmountsret);
  int virFileGetMountReverseSubtree(const char *mtabpath,
                                    const char *prefix,
                                    char ***mountsret,
                                    size_t *nmountsret);

Add a new virfiletest.c test case to validate the new code.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Our backing file chain code was not very robust to an ill-timed
EINTR, which could lead to a short read causing us to randomly
treat metadata differently than usual.  But the existing
virFileReadLimFD forces an error if we don't read the entire
file, even though we only care about the header of the file.
So add a new virFile function that does what we want.

* src/util/virfile.h (virFileReadHeaderFD): New prototype.
* src/util/virfile.c (virFileReadHeaderFD): New function.
* src/libvirt_private.syms (virfile.h): Export it.
* src/util/virstoragefile.c (virStorageFileGetMetadataInternal)
(virStorageFileProbeFormatFromFD): Use it.
Signed-off-by: NEric Blake <eblake@redhat.com>

Add a function for efficiently checking if a path is a filesystem
mount point.

NB will not work for bind mounts, only true filesystem mounts.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

We can't use GNULIB's fprintf-posix due to licensing
incompatibilities. We do already have a portable
formatting via virAsprintf() which we got from GNULIB
though. We can use to create a virFilePrintf() function.

But really gnulib could just provide a 'fprintf'
module, that depended on just its 'asprintf' module.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add a virFileNBDDeviceAssociate method, which given a filename
will setup a NBD device, using qemu-nbd as the server.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

These all existed before virfile.c was created, and for some reason
weren't moved.

This is mostly straightfoward, although the syntax rule prohibiting
write() had to be changed to have an exception for virfile.c instead
of virutil.c.

This movement pointed out that there is a function called
virBuildPath(), and another almost identical function called
virFileBuildPath(). They really should be a single function, which
I'll take care of as soon as I figure out what the arglist should look
like.

Introduce a method virFileDeleteTree for recursively deleting
an entire directory tree
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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().

Currently, we use iohelper when saving/restoring a domain.
However, if there's some kind of error (like I/O) it is not
propagated to libvirt. Since it is not qemu who is doing
the actual write() it will not get error. The iohelper does.
Therefore we should check for iohelper errors as it makes
libvirt more user friendly.

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c

While it is not currently used elsewhere in libvirt, the code
for finding a free loop device & associating a file with it
is not LXC specific. Move it into the viffile.{c,h} file where
potentially shared code is more commonly kept.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The ignore_value macro is used across libvirt. This patch includes it in
the internal header and cleans all other includes.

When libvirtd forks off a new child, the child then calls virLogReset(),
which ends up closing file descriptors used as log outputs. However, we
recently started logging closed file descriptors, which means we need to
lock logging mutex which was already locked by virLogReset(). We don't
really want to log anything when we are in the process of closing log
outputs.

EBADF errors are logged as warnings as they normally indicate a double
close bug. This patch also provides VIR_MASS_CLOSE helper to be user in
the only case of mass close after fork when EBADF should rather be
ignored.

When libvirtd is started, we create "libvirt/qemu" directories under
hugetlbfs mount point. Only the "qemu" subdirectory is chowned to qemu
user and "libvirt" remains owned by root. If umask was too restrictive
when libvirtd started, qemu user may lose access to "qemu"
subdirectory. Let's explicitly grant search permissions to "libvirt"
directory for all users.

* src/util/virfile.h: the virFileWrapperFdFlags being defined as
  a globa variable instead of a type ended up generating a duplicate
  symbol error.
* AUTHORS: added Lincoln Myers

virFileDirectFd was used for accessing files opened with O_DIRECT using
libvirt_iohelper. We will want to use the helper for accessing files
regardless on O_DIRECT and thus virFileDirectFd was generalized and
renamed to virFileWrapperFd.

Add a virFileTouch API which ensures that a file will always
exist, even if zero length

* src/util/virfile.c, src/util/virfile.h,
  src/libvirt_private.syms: Introduce virFileTouch

When saving config files we just overwrite old content of the file. In
case something fails during that process (e.g. disk gets full) we lose
both old and new content. This patch makes the process more robust by
writing the new content into a separate file and only if that succeeds
the original file is atomically replaced with the new one.

Add some simple wrappers around the fcntl() discretionary file
locking capability.

* src/util/util.c, src/util/util.h, src/libvirt_private.syms: Add
  virFileLock and virFileUnlock APIs

O_DIRECT has stringent requirements.  Rather than make lots of changes
at each site that wants to use O_DIRECT, it is easier to offload
the work through a helper process that mirrors the I/O between a
pipe and the actual direct fd, so that the other end of the pipe
no longer has to worry about constraints.

Plus, if the kernel ever gains better posix_fadvise support, then we
only have to touch a single file to let all callers benefit from a
more efficient way to avoid file system caching.

* src/util/virfile.h (virFileDirectFdFlag, virFileDirectFdNew)
(virFileDirectFdClose, virFileDirectFdFree): New prototypes.
* src/util/virdirect.c: Implement new wrapper object.
* src/libvirt_private.syms (virfile.h): Export new symbols.
* cfg.mk (useless_free_options): Add to list.
* po/POTFILES.in: Add new translations.

In preparation for a future patch adding new virFile APIs.

* src/util/files.h, src/util/files.c: Move...
* src/util/virfile.h, src/util/virfile.c: ...here, and rename
functions to virFile prefix.  Macro names are intentionally
left alone.
* *.c: All '#include "files.h"' uses changed.
* src/Makefile.am (UTIL_SOURCES): Reflect rename.
* cfg.mk (exclude_file_name_regexp--sc_prohibit_close): Likewise.
* src/libvirt_private.syms: Likewise.
* docs/hacking.html.in: Likewise.
* HACKING: Regenerate.

* cfg.mk (sc_copyright_format): Add to rule.
* src/util/files.h: Fix offenders.
* src/util/files.c: Likewise.

Remove the <stdbool.h> header from all source files / headers
and just put it into internal.h

* src/internal.h: Add <stdbool.h>

commit f1fe9671 was supposed to make sure we use files.h
macros to avoid double close, but it didn't work.

Meanwhile, virCommand is vastly superior to system(), fork(),
and popen() (also to virExec, but we haven't completed that
conversion), so enforce that, too.

* cfg.mk (sc_prohibit_close): Fix typo that excluded close, and
add pclose.
(sc_prohibit_fork_wrappers): New rule, for fork, system, and popen.
* .x-sc_prohibit_close: More exemptions.
* .x-sc_prohibit_fork_wrappers: New file.
* Makefile.am (syntax_check_exceptions): Ship new file.
* src/datatypes.c (virReleaseConnect): Tweak comment to avoid
false positive.
* src/util/files.h (VIR_CLOSE): Likewise.

Similarly to deprecating close(), I am now deprecating fclose() and
introduce VIR_FORCE_FCLOSE() and VIR_FCLOSE(). Also, fdopen() is replaced with
VIR_FDOPEN().

Most of the files are opened in read-only mode, so usage of
VIR_FORCE_CLOSE() seemed appropriate. Others that are opened in write
mode already had the fclose()<  0 check and I converted those to
VIR_FCLOSE()<  0.

I did not find occurrences of possible double-closed files on the way.