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storage: Move virStorageFileGetMetadata to the storage driver 

My future work will modify the metadata crawler function to use the
storage driver file APIs to access the files instead of accessing them
directly so that we will be able to request the metadata for remote
files too. To avoid linking the storage driver to every helper file
using the utils code, the backing chain traversal function needs to be
moved to the storage driver source.

Additionally the virt-aa-helper and virstoragetest programs need to be
linked with the storage driver as a result of this change.
This commit is contained in:
Peter Krempa 2014-04-24 12:14:01 +02:00
parent 4cb2505557
commit 713cc3b0a7
11 changed files with 259 additions and 239 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
cfg.mk
View File

@ -774,7 +774,7 @@ sc_prohibit_cross_inclusion:
access/ | conf/) safe="($$dir|conf|util)";; \
locking/) safe="($$dir|util|conf|rpc)";; \
cpu/| network/| node_device/| rpc/| security/| storage/) \
safe="($$dir|util|conf)";; \
safe="($$dir|util|conf|storage)";; \
xenapi/ | xenxs/ ) safe="($$dir|util|conf|xen)";; \
*) safe="($$dir|$(mid_dirs)|util)";; \
esac; \

2
src/Makefile.am
View File

@ -2587,8 +2587,10 @@ virt_aa_helper_LDFLAGS = \
$(PIE_LDFLAGS) \
$(NULL)
virt_aa_helper_LDADD = \
libvirt.la \
libvirt_conf.la \
libvirt_util.la \
libvirt_driver_storage_impl.la \
../gnulib/lib/libgnu.la
if WITH_DTRACE_PROBES
virt_aa_helper_LDADD += libvirt_probes.lo

2
src/libvirt_private.syms
View File

@ -1863,9 +1863,9 @@ virStorageFileFeatureTypeToString;
virStorageFileFormatTypeFromString;
virStorageFileFormatTypeToString;
virStorageFileGetLVMKey;
virStorageFileGetMetadata;
virStorageFileGetMetadataFromBuf;
virStorageFileGetMetadataFromFD;
virStorageFileGetMetadataFromFDInternal;
virStorageFileGetSCSIKey;
virStorageFileIsClusterFS;
virStorageFileParseChainIndex;

2
src/qemu/qemu_domain.c
View File

@ -40,6 +40,8 @@
#include "virstoragefile.h"
#include "virstring.h"
#include "storage/storage_driver.h"
#include <sys/time.h>
#include <fcntl.h>

2
src/security/virt-aa-helper.c
View File

@ -55,6 +55,8 @@
#include "virrandom.h"
#include "virstring.h"
#include "storage/storage_driver.h"
#define VIR_FROM_THIS VIR_FROM_SECURITY
static char *progname;

233
src/storage/storage_driver.c
View File

@ -49,6 +49,7 @@
#include "configmake.h"
#include "virstring.h"
#include "viraccessapicheck.h"
#include "dirname.h"
#define VIR_FROM_THIS VIR_FROM_STORAGE
@ -3041,3 +3042,235 @@ virStorageFileAccess(virStorageSourcePtr src,
return src->drv->backend->storageFileAccess(src, mode);
}
/**
* Given a starting point START (a directory containing the original
* file, if the original file was opened via a relative path; ignored
* if NAME is absolute), determine the location of the backing file
* NAME (possibly relative), and compute the relative DIRECTORY
* (optional) and CANONICAL (mandatory) location of the backing file.
* Return 0 on success, negative on error.
*/
static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(4)
virFindBackingFile(const char *start, const char *path,
char **directory, char **canonical)
{
/* FIXME - when we eventually allow non-raw network devices, we
* must ensure that we handle backing files the same way as qemu.
* For a qcow2 top file of gluster://server/vol/img, qemu treats
* the relative backing file 'rel' as meaning
* 'gluster://server/vol/rel', while the backing file '/abs' is
* used as a local file. But we cannot canonicalize network
* devices via canonicalize_file_name(), because they are not part
* of the local file system. */
char *combined = NULL;
int ret = -1;
if (*path == '/') {
/* Safe to cast away const */
combined = (char *)path;
} else if (virAsprintf(&combined, "%s/%s", start, path) < 0) {
goto cleanup;
}
if (directory && !(*directory = mdir_name(combined))) {
virReportOOMError();
goto cleanup;
}
if (virFileAccessibleAs(combined, F_OK, geteuid(), getegid()) < 0) {
virReportSystemError(errno,
_("Cannot access backing file '%s'"),
combined);
goto cleanup;
}
if (!(*canonical = canonicalize_file_name(combined))) {
virReportSystemError(errno,
_("Can't canonicalize path '%s'"), path);
goto cleanup;
}
ret = 0;
cleanup:
if (combined != path)
VIR_FREE(combined);
return ret;
}
/* Recursive workhorse for virStorageFileGetMetadata. */
static int
virStorageFileGetMetadataRecurse(virStorageSourcePtr src,
const char *canonPath,
uid_t uid, gid_t gid,
bool allow_probe,
virHashTablePtr cycle)
{
int fd;
int ret = -1;
virStorageSourcePtr backingStore = NULL;
int backingFormat;
VIR_DEBUG("path=%s canonPath=%s dir=%s format=%d uid=%d gid=%d probe=%d",
src->path, canonPath, NULLSTR(src->relDir), src->format,
(int)uid, (int)gid, allow_probe);
if (virHashLookup(cycle, canonPath)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("backing store for %s is self-referential"),
src->path);
return -1;
}
if (virHashAddEntry(cycle, canonPath, (void *)1) < 0)
return -1;
if (virStorageSourceGetActualType(src) != VIR_STORAGE_TYPE_NETWORK) {
if ((fd = virFileOpenAs(src->path, O_RDONLY, 0, uid, gid, 0)) < 0) {
virReportSystemError(-fd, _("Failed to open file '%s'"),
src->path);
return -1;
}
if (virStorageFileGetMetadataFromFDInternal(src, fd,
&backingFormat) < 0) {
VIR_FORCE_CLOSE(fd);
return -1;
}
if (VIR_CLOSE(fd) < 0)
VIR_WARN("could not close file %s", src->path);
} else {
/* TODO: currently we call this only for local storage */
return 0;
}
/* check whether we need to go deeper */
if (!src->backingStoreRaw)
return 0;
if (VIR_ALLOC(backingStore) < 0)
return -1;
if (VIR_STRDUP(backingStore->relPath, src->backingStoreRaw) < 0)
goto cleanup;
if (virStorageIsFile(src->backingStoreRaw)) {
backingStore->type = VIR_STORAGE_TYPE_FILE;
if (virFindBackingFile(src->relDir,
src->backingStoreRaw,
&backingStore->relDir,
&backingStore->path) < 0) {
/* the backing file is (currently) unavailable, treat this
* file as standalone:
* backingStoreRaw is kept to mark broken image chains */
VIR_WARN("Backing file '%s' of image '%s' is missing.",
src->backingStoreRaw, src->path);
ret = 0;
goto cleanup;
}
} else {
/* TODO: To satisfy the test case, copy the network URI as path. This
* will be removed later. */
backingStore->type = VIR_STORAGE_TYPE_NETWORK;
if (VIR_STRDUP(backingStore->path, src->backingStoreRaw) < 0)
goto cleanup;
}
if (backingFormat == VIR_STORAGE_FILE_AUTO && !allow_probe)
backingStore->format = VIR_STORAGE_FILE_RAW;
else if (backingFormat == VIR_STORAGE_FILE_AUTO_SAFE)
backingStore->format = VIR_STORAGE_FILE_AUTO;
else
backingStore->format = backingFormat;
if (virStorageFileGetMetadataRecurse(backingStore,
backingStore->path,
uid, gid, allow_probe,
cycle) < 0) {
/* if we fail somewhere midway, just accept and return a
* broken chain */
ret = 0;
goto cleanup;
}
src->backingStore = backingStore;
backingStore = NULL;
ret = 0;
cleanup:
virStorageSourceFree(backingStore);
return ret;
}
/**
* virStorageFileGetMetadata:
*
* Extract metadata about the storage volume with the specified
* image format. If image format is VIR_STORAGE_FILE_AUTO, it
* will probe to automatically identify the format. Recurses through
* the entire chain.
*
* Open files using UID and GID (or pass -1 for the current user/group).
* Treat any backing files without explicit type as raw, unless ALLOW_PROBE.
*
* Callers are advised never to use VIR_STORAGE_FILE_AUTO as a
* format, since a malicious guest can turn a raw file into any
* other non-raw format at will.
*
* Caller MUST free result after use via virStorageSourceFree.
*/
int
virStorageFileGetMetadata(virStorageSourcePtr src,
uid_t uid, gid_t gid,
bool allow_probe)
{
VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d",
src->path, src->format, (int)uid, (int)gid, allow_probe);
virHashTablePtr cycle = NULL;
char *canonPath = NULL;
int ret = -1;
if (!(cycle = virHashCreate(5, NULL)))
return -1;
if (virStorageSourceGetActualType(src) != VIR_STORAGE_TYPE_NETWORK) {
if (!(canonPath = canonicalize_file_name(src->path))) {
virReportSystemError(errno, _("unable to resolve '%s'"),
src->path);
goto cleanup;
}
if (!src->relPath &&
VIR_STRDUP(src->relPath, src->path) < 0)
goto cleanup;
if (!src->relDir &&
!(src->relDir = mdir_name(src->path))) {
virReportOOMError();
goto cleanup;
}
} else {
/* TODO: currently unimplemented for non-local storage */
ret = 0;
goto cleanup;
}
if (src->format <= VIR_STORAGE_FILE_NONE)
src->format = allow_probe ? VIR_STORAGE_FILE_AUTO : VIR_STORAGE_FILE_RAW;
ret = virStorageFileGetMetadataRecurse(src, canonPath, uid, gid,
allow_probe, cycle);
cleanup:
VIR_FREE(canonPath);
virHashFree(cycle);
return ret;
}

5
src/storage/storage_driver.h
View File

@ -44,6 +44,11 @@ ssize_t virStorageFileReadHeader(virStorageSourcePtr src,
const char *virStorageFileGetUniqueIdentifier(virStorageSourcePtr src);
int virStorageFileAccess(virStorageSourcePtr src, int mode);
int virStorageFileGetMetadata(virStorageSourcePtr src,
uid_t uid, gid_t gid,
bool allow_probe)
ATTRIBUTE_NONNULL(1);
int storageRegister(void);
#endif /* __VIR_STORAGE_DRIVER_H__ */

233
src/util/virstoragefile.c
View File

@ -28,7 +28,6 @@
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include "dirname.h"
#include "viralloc.h"
#include "virerror.h"
#include "virlog.h"
@ -565,62 +564,6 @@ qedGetBackingStore(char **res,
return BACKING_STORE_OK;
}
/**
* Given a starting point START (a directory containing the original
* file, if the original file was opened via a relative path; ignored
* if NAME is absolute), determine the location of the backing file
* NAME (possibly relative), and compute the relative DIRECTORY
* (optional) and CANONICAL (mandatory) location of the backing file.
* Return 0 on success, negative on error.
*/
static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(4)
virFindBackingFile(const char *start, const char *path,
char **directory, char **canonical)
{
/* FIXME - when we eventually allow non-raw network devices, we
* must ensure that we handle backing files the same way as qemu.
* For a qcow2 top file of gluster://server/vol/img, qemu treats
* the relative backing file 'rel' as meaning
* 'gluster://server/vol/rel', while the backing file '/abs' is
* used as a local file. But we cannot canonicalize network
* devices via canonicalize_file_name(), because they are not part
* of the local file system. */
char *combined = NULL;
int ret = -1;
if (*path == '/') {
/* Safe to cast away const */
combined = (char *)path;
} else if (virAsprintf(&combined, "%s/%s", start, path) < 0) {
goto cleanup;
}
if (directory && !(*directory = mdir_name(combined))) {
virReportOOMError();
goto cleanup;
}
if (virFileAccessibleAs(combined, F_OK, geteuid(), getegid()) < 0) {
virReportSystemError(errno,
_("Cannot access backing file '%s'"),
combined);
goto cleanup;
}
if (!(*canonical = canonicalize_file_name(combined))) {
virReportSystemError(errno,
_("Can't canonicalize path '%s'"), path);
goto cleanup;
}
ret = 0;
cleanup:
if (combined != path)
VIR_FREE(combined);
return ret;
}
static bool
virStorageFileMatchesMagic(int format,
@ -1012,7 +955,7 @@ virStorageFileGetMetadataFromBuf(const char *path,
/* Internal version that also supports a containing directory name. */
static int
int
virStorageFileGetMetadataFromFDInternal(virStorageSourcePtr meta,
int fd,
int *backingFormat)
@ -1111,180 +1054,6 @@ virStorageFileGetMetadataFromFD(const char *path,
}
/* Recursive workhorse for virStorageFileGetMetadata. */
static int
virStorageFileGetMetadataRecurse(virStorageSourcePtr src,
const char *canonPath,
uid_t uid, gid_t gid,
bool allow_probe,
virHashTablePtr cycle)
{
int fd;
int ret = -1;
virStorageSourcePtr backingStore = NULL;
int backingFormat;
VIR_DEBUG("path=%s canonPath=%s dir=%s format=%d uid=%d gid=%d probe=%d",
src->path, canonPath, NULLSTR(src->relDir), src->format,
(int)uid, (int)gid, allow_probe);
if (virHashLookup(cycle, canonPath)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("backing store for %s is self-referential"),
src->path);
return -1;
}
if (virHashAddEntry(cycle, canonPath, (void *)1) < 0)
return -1;
if (virStorageSourceGetActualType(src) != VIR_STORAGE_TYPE_NETWORK) {
if ((fd = virFileOpenAs(src->path, O_RDONLY, 0, uid, gid, 0)) < 0) {
virReportSystemError(-fd, _("Failed to open file '%s'"),
src->path);
return -1;
}
if (virStorageFileGetMetadataFromFDInternal(src, fd,
&backingFormat) < 0) {
VIR_FORCE_CLOSE(fd);
return -1;
}
if (VIR_CLOSE(fd) < 0)
VIR_WARN("could not close file %s", src->path);
} else {
/* TODO: currently we call this only for local storage */
return 0;
}
/* check whether we need to go deeper */
if (!src->backingStoreRaw)
return 0;
if (VIR_ALLOC(backingStore) < 0)
return -1;
if (VIR_STRDUP(backingStore->relPath, src->backingStoreRaw) < 0)
goto cleanup;
if (virStorageIsFile(src->backingStoreRaw)) {
backingStore->type = VIR_STORAGE_TYPE_FILE;
if (virFindBackingFile(src->relDir,
src->backingStoreRaw,
&backingStore->relDir,
&backingStore->path) < 0) {
/* the backing file is (currently) unavailable, treat this
* file as standalone:
* backingStoreRaw is kept to mark broken image chains */
VIR_WARN("Backing file '%s' of image '%s' is missing.",
src->backingStoreRaw, src->path);
ret = 0;
goto cleanup;
}
} else {
/* TODO: To satisfy the test case, copy the network URI as path. This
* will be removed later. */
backingStore->type = VIR_STORAGE_TYPE_NETWORK;
if (VIR_STRDUP(backingStore->path, src->backingStoreRaw) < 0)
goto cleanup;
}
if (backingFormat == VIR_STORAGE_FILE_AUTO && !allow_probe)
backingStore->format = VIR_STORAGE_FILE_RAW;
else if (backingFormat == VIR_STORAGE_FILE_AUTO_SAFE)
backingStore->format = VIR_STORAGE_FILE_AUTO;
else
backingStore->format = backingFormat;
if (virStorageFileGetMetadataRecurse(backingStore,
backingStore->path,
uid, gid, allow_probe,
cycle) < 0) {
/* if we fail somewhere midway, just accept and return a
* broken chain */
ret = 0;
goto cleanup;
}
src->backingStore = backingStore;
backingStore = NULL;
ret = 0;
cleanup:
virStorageSourceFree(backingStore);
return ret;
}
/**
* virStorageFileGetMetadata:
*
* Extract metadata about the storage volume with the specified
* image format. If image format is VIR_STORAGE_FILE_AUTO, it
* will probe to automatically identify the format. Recurses through
* the entire chain.
*
* Open files using UID and GID (or pass -1 for the current user/group).
* Treat any backing files without explicit type as raw, unless ALLOW_PROBE.
*
* Callers are advised never to use VIR_STORAGE_FILE_AUTO as a
* format, since a malicious guest can turn a raw file into any
* other non-raw format at will.
*
* Caller MUST free result after use via virStorageSourceFree.
*/
int
virStorageFileGetMetadata(virStorageSourcePtr src,
uid_t uid, gid_t gid,
bool allow_probe)
{
VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d",
src->path, src->format, (int)uid, (int)gid, allow_probe);
virHashTablePtr cycle = NULL;
char *canonPath = NULL;
int ret = -1;
if (!(cycle = virHashCreate(5, NULL)))
return -1;
if (virStorageSourceGetActualType(src) != VIR_STORAGE_TYPE_NETWORK) {
if (!(canonPath = canonicalize_file_name(src->path))) {
virReportSystemError(errno, _("unable to resolve '%s'"),
src->path);
goto cleanup;
}
if (!src->relPath &&
VIR_STRDUP(src->relPath, src->path) < 0)
goto cleanup;
if (!src->relDir &&
!(src->relDir = mdir_name(src->path))) {
virReportOOMError();
goto cleanup;
}
} else {
/* TODO: currently unimplemented for non-local storage */
ret = 0;
goto cleanup;
}
if (src->format <= VIR_STORAGE_FILE_NONE)
src->format = allow_probe ? VIR_STORAGE_FILE_AUTO : VIR_STORAGE_FILE_RAW;
ret = virStorageFileGetMetadataRecurse(src, canonPath, uid, gid,
allow_probe, cycle);
cleanup:
VIR_FREE(canonPath);
virHashFree(cycle);
return ret;
}
/**
* virStorageFileChainCheckBroken
*

7
src/util/virstoragefile.h
View File

@ -265,10 +265,9 @@ struct _virStorageSource {
int virStorageFileProbeFormat(const char *path, uid_t uid, gid_t gid);
int virStorageFileGetMetadata(virStorageSourcePtr src,
uid_t uid, gid_t gid,
bool allow_probe)
ATTRIBUTE_NONNULL(1);
int virStorageFileGetMetadataFromFDInternal(virStorageSourcePtr meta,
int fd,
int *backingFormat);
virStorageSourcePtr virStorageFileGetMetadataFromFD(const char *path,
int fd,
int format,

8
tests/Makefile.am
View File

@ -869,7 +869,13 @@ virstringtest_LDADD = $(LDADDS)
virstoragetest_SOURCES = \
virstoragetest.c testutils.h testutils.c
virstoragetest_LDADD = $(LDADDS)
virstoragetest_LDADD = $(LDADDS) \
../src/libvirt.la \
../src/libvirt_conf.la \
../src/libvirt_util.la \
../src/libvirt_driver_storage_impl.la \
../gnulib/lib/libgnu.la \
$(NULL)
viridentitytest_SOURCES = \
viridentitytest.c testutils.h testutils.c

2
tests/virstoragetest.c
View File

@ -31,6 +31,8 @@
#include "virstring.h"
#include "dirname.h"
#include "storage/storage_driver.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("tests.storagetest");