This patch fixes a couple of complaints from valgrind when tickling libvirtd with SIGHUP.
The first two files contain fixes for memory leaks. The 3rd one initializes an uninitialized variable. The 4th one is another memory leak.
virDiskNameToIndex has a list of disk name prefixes that it uses in the
process of finding the disk's index. This list is missing "ubd" which
is the disk prefix used for UML domains.
Signed-off-by: Soren Hansen <soren@linux2go.dk>
virDirCreate also previously returned 0 on success and errno on
failure. This makes it fit the recommended convention of returning 0
on success, -errno (ie a negative number) on failure.
virFileOperation previously returned 0 on success, or the value of
errno on failure. Although there are other functions in libvirt that
use this convention, the preferred (and more common) convention is to
return 0 on success and -errno (or simply -1 in some cases) on
failure. This way the check for failure is always (ret < 0).
* src/util/util.c - change virFileOperation and virFileOperationNoFork to
return -errno on failure.
* src/storage/storage_backend.c, src/qemu/qemu_driver.c
- change the hook functions passed to virFileOperation to return
-errno on failure.
Any error message raised after the process has forked needs
to be followed by virDispatchError, otherwise we have no chance of
ever seeing it. This was selectively done for hook functions in the past,
but really applies to all post-fork errors.
We've been running into a lot of situations where
virGetHostname() is returning "localhost", where a plain
gethostname() would have returned the correct thing. This
is because virGetHostname() is *always* trying to canonicalize
the name returned from gethostname(), even when it doesn't
have to.
This patch changes virGetHostname so that if the value returned
from gethostname() is already FQDN or localhost, it returns
that string directly. If the value returned from gethostname()
is a shortened hostname, then we try to canonicalize it. If
that succeeds, we returned the canonicalized hostname. If
that fails, and/or returns "localhost", then we just return
the original string we got from gethostname() and hope for
the best.
Note that after this patch it is up to clients to check whether
"localhost" is an allowed return value. The only place
where it's currently not is in qemu migration.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
Spurious / in a pool target path makes life difficult for apps using the
GetVolByPath, and doing other path based comparisons with pools. This
has caused a few issues for virt-manager users:
https://bugzilla.redhat.com/show_bug.cgi?id=494005https://bugzilla.redhat.com/show_bug.cgi?id=593565
Add a new util API which removes spurious /, virFileSanitizePath. Sanitize
target paths when parsing pool XML, and for paths passed to GetVolByPath.
v2: Leading // must be preserved, properly sanitize path=/, sanitize
away /./ -> /
v3: Properly handle starting ./ and ending /.
v4: Drop all '.' handling, just sanitize / for now.
virFileResolveLink was returning a positive value on error,
thus confusing callers that assumed failure was < 0. The
confusion is further evidenced by callers that would have
ended up calling virReportSystemError with a negative value
instead of a valid errno.
Fixes Red Hat BZ #591363.
* src/util/util.c (virFileResolveLink): Live up to documentation.
* src/qemu/qemu_security_dac.c
(qemuSecurityDACRestoreSecurityFileLabel): Adjust callers.
* src/security/security_selinux.c
(SELinuxRestoreSecurityFileLabel): Likewise.
* src/storage/storage_backend_disk.c
(virStorageBackendDiskDeleteVol): Likewise.
Gnulib can guarantee that pthread.h exists, but for now, it is a dummy
header with no support for most pthread_* functions. Modify our
use of pthread to use function checks, rather than header checks,
to determine how much pthread support is present.
* bootstrap.conf (gnulib_modules): Add pthread.
* configure.ac: Drop all pthread.h checks. Optimize function
checks. Add check for pthread functions.
* src/Makefile.am (libvirt_lxc_LDADD): Ensure proper link.
* src/remote/remote_driver.c (remoteIOEventLoop): Depend on
pthread_sigmask, now that gnulib guarantees pthread.h.
* src/util/util.c (virFork): Likewise.
* src/util/threads.c (threads-pthread.c): Depend on
pthread_mutexattr_init, as a witness of full pthread support.
* src/util/threads.h (threads-pthread.h): Likewise.
Detected by clang. POSIX requires that the second argument to
va_start be the name of the last variable; and in some implementations,
passing *path instead of path would dereference bogus memory instead
of pulling arguments off the stack.
* src/util/util.c (virBuildPathInternal): Use correct argument to
va_start.
Add an empty body for virCondWaitUntil and move virPipeReadUntilEOF
out of the '#ifndef WIN32' block, because it compiles fine with MinGW
in combination with gnulib.
Necessary on cygwin, where uid_t and gid_t are 4-byte long rather
than int, causing gcc -Wformat warnings.
* src/util/util.c (virFileOperationNoFork, virDirCreateNoFork)
(virFileOperation, virDirCreate, virGetUserEnt): Cast uid_t and
gid_t before passing to printf.
* .gitignore: Ignore Windows executables.
virParseVersionString uses virStrToLong_ui instead of sscanf.
This also fixes a bug in the UML driver, that always returned 0
as version number.
Introduce STRSKIP to check if a string has a certain prefix and
to skip this prefix.
used to read the data from virExec stdout/err file descriptors
* src/util/util.c src/util/util.h: not static anymore and export it
* src/libvirt_private.syms: allow access internally
Even if gnulib can provide stubs, it won't help that much. So just
replace affected util functions (virFileOperation and virDirCreate)
with stubs on Windows. Both functions aren't used on libvirt's
client side, so this is fine for MinGW builds.
to saferead_lim, which interprets it as a size_t.
* src/util/util.c (virFileReadLimFD): Do not malfunction when
maxlen < -1. Return -1,EINVAL in that case. Handle maxlen==0
in the same manner.
Various safezero() implementations used either -1, errno or -errno
return values. This patch fixes them all to return -1 and set errno
appropriately.
There was also a bug in size parameter passed to safewrite() which could
result in an attempt to write gigabytes out of a megabyte buffer.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
It turns out it is also useful to be able to perform other operations
on a file created while running as a different uid (eg, write things
to that file), and possibly to do this to a file that already
exists. This patch adds an optional hook function to the renamed (for
more accuracy of purpose) virFileOperation; the hook will be called
after the file has been opened (possibly created) and gid/mode
checked/set, before closing it.
As with the other operations on the file, if the VIR_FILE_OP_AS_UID
flag is set, this hook function will be called in the context of a
child process forked from the process that called virFileOperation.
The implication here is that, while all data in memory is available to
this hook function, any modification to that data will not be seen by
the caller - the only indication in memory of what happened in the
hook will be the return value (which the hook should set to 0 on
success, or one of the standard errno values on failure).
Another piece of making the function more flexible was to add an
"openflags" argument. This arg should contain exactly the flags to be
passed to open(2), eg O_RDWR | O_EXCL, etc.
In the process of adding the hook to virFileOperation, I also realized
that the bits to fix up file owner/group/mode settings after creation
were being done in the parent process, which could fail, so I moved
them to the child process where they should be.
* src/util/util.[ch]: rename and rework virFileCreate-->virFileOperation,
and redo flags in virDirCreate
* storage/storage_backend.c, storage/storage_backend_fs.c: update the
calls to virFileOperation/virDirCreate to reflect changes in the API,
but don't yet take advantage of the hook.
If the hostname as returned by "gethostname" resolves
to "localhost" (as it does with the broken Fedora-12
installer), then live migration will fail because the
source will try to migrate to itself. Detect this
situation up-front and abort the live migration before
we do any real work.
* src/util/util.h src/util/util.c: add a new virGetHostnameLocalhost
with an optional localhost check, and rewire virGetHostname() to use
it
* src/libvirt_private.syms: expose the new function
* src/qemu/qemu_driver.c: use it in qemudDomainMigratePrepare2()
For __virExec() this is a semantic NOP except for when fork()
fails. __virExec() would previously forget to restore the signal mask
in this case; virFork() corrects this behavior.
virFileCreate() and virDirCreate() gain the code to reset the logging
and properly deal with the signal handling race condition.
This also removes a log message that had a typo ("cannot fork o create
file '%s'") - this error is now logged in a more generic manner in
virFork() (more generic, but really just as informative, since the
fact that it's forking to create a file is immaterial to the fact that
it simply can't fork)
* src/util/util.c: use the generic virFork() in the 3 functions
virFork() contains bookkeeping that must be done any time a process
forks. Currently this includes:
1) Call virLogLock() prior to fork() and virLogUnlock() just after,
to avoid a deadlock if some other thread happens to hold that lock
during the fork.
2) Reset the logging hooks and send all child process log messages to
stderr.
3) Block all signals prior to fork(), then either a) reset the signal
mask for the parent process, or b) clear the signal mask for the
child process.
Note that the signal mask handling in __virExec erroneously fails to
restore the signal mask when fork() fails. virFork() fixes this
problem.
Other than this, it attempts to behave as closely to fork() as
possible (including preserving errno for the caller), with a couple
exceptions:
1) The return value is 0 (success) or -1 (failure), while the pid is
returned via the pid_t* argument. Like fork(), if pid < 0 there is
no child process, otherwise both the child and the parent will
return to the caller, and both should look at the return value,
which will indicate if some of the extra processing outlined above
encountered an error.
2) If virFork() returns with pid < 0 or with a return value < 0
indicating an error condition, the error has already been
reported. You can log an additional message if you like, but it
isn't necessary, and may be awkwardly extraneous.
Note that virFork()'s child process will *never* call _exit() - if a
child process is created, it will return to the caller.
* util.c util.h: add virFork() function, based on what is currently
done in __virExec().
Similar fix as previous one but for fork() usage when creating
a file or directory
* src/util/util.c: virLogLock() and virLogUnlock() around fork()
in virFileCreate() and virDirCreateSimple()
Ad pointed out by Dan Berrange:
So if some thread in libvirtd is currently executing a logging call,
while another thread calls virExec(), that other thread no longer
exists in the child, but its lock is never released. So when the
child then does virLogReset() it deadlocks.
The only way I see to address this, is for the parent process to call
virLogLock(), immediately before fork(), and then virLogUnlock()
afterwards in both parent & child. This will ensure that no other
thread
can be holding the lock across fork().
* src/util/logging.[ch] src/libvirt_private.syms: export virLogLock() and
virLogUnlock()
* src/util/util.c: lock just before forking and unlock just after - in
both parent and child.
* src/util/util.c (virGetUserID, virGetGroupID): In the unlikely event
that sysconf(_SC_GETPW_R_SIZE_MAX) fails, don't use -1 as the size in
the subsequent allocation.
On RHEL-5 the qemu-kvm binary is located in /usr/libexec.
To reduce confusion for people trying to run upstream libvirt
on RHEL-5 machines, make the qemu driver look in /usr/libexec
for the qemu-kvm binary.
To make this work, I modified virFindFileInPath to handle an
absolute path correctly. I also ran into an issue where
NULL was sometimes being passed for the file parameter
to virFindFileInPath; it didn't crash prior to this patch
since it was building paths like /usr/bin/(null). This
is non-standard behavior, though, so I added a NULL
check at the beginning.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
* src/util/util.c (virGetUserEnt): In the unlikely event that
sysconf(_SC_GETPW_R_SIZE_MAX) fails, don't use -1 as the size in
the subsequent allocation.
virFileMakePath is a recursive function that was creates a buffer
PATH_MAX bytes long for each recursion (one recursion for each element
in the path). This changes it to have no buffers on the stack, and to
allocate just one buffer total, no matter how many elements are in the
path. Because the modified algorithm requires a char* to be passed in
rather than const char *, it is now 2 functions - a toplevel API
function that remains identical in function, and a 2nd helper function
called for the recursions, which 1) doesn't allocate anything, and 2)
takes a char* arg, so it can modify the contents.
* src/util/util.c: rewrite virFileMakePath
These functions create a new file or directory with the given
uid/gid. If the flag VIR_FILE_CREATE_AS_UID is given, they do this by
forking a new process, calling setuid/setgid in the new process, and
then creating the file. This is better than simply calling open then
fchown, because in the latter case, a root-squashing nfs server would
create the new file as user nobody, then refuse to allow fchown.
If VIR_FILE_CREATE_AS_UID is not specified, the simpler tactic of
creating the file/dir, then chowning is is used. This gives better
results in cases where the parent directory isn't on a root-squashing
NFS server, but doesn't give permission for the specified uid/gid to
create files. (Note that if the fork/setuid method fails to create the
file due to access privileges, the parent process will make a second
attempt using this simpler method.)
If the bit VIR_FILE_CREATE_ALLOW_EXIST is set in the flags, an
existing file/directory will not cause an error; in this case, the
function will simply set the permissions of the file/directory to
those requested. If VIR_FILE_CREATE_ALLOW_EXIST is not specified, an
existing file/directory is considered (and reported as) an error.
Return from both of these functions is 0 on success, or the value of
errno if there was a failure.
* src/util/util.[ch]: add the 2 new util functions
