External/libvirt
1
0
Fork 0
mirror of https://gitlab.com/libvirt/libvirt.git synced 2024-11-02 11:21:12 +00:00
Code Issues Packages Projects Releases Wiki Activity
a1fe02f0e9
libvirt/src/util/virstoragefile.c
Ján Tomko 6e46477c23 Fix size probing for VDI images 
Commit 027bf2ea used the wrong offset: the text field at the start
of the header has 64 bytes, not 68. [1]

Bug: https://bugzilla.redhat.com/show_bug.cgi?id=921452

[1] https://forums.virtualbox.org/viewtopic.php?p=29267#p29267
2013-03-14 15:12:06 +01:00

1365 lines
40 KiB
C
Raw Blame History

/*
* virstoragefile.c: file utility functions for FS storage backend
*
* Copyright (C) 2007-2013 Red Hat, Inc.
* Copyright (C) 2007-2008 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include "virstoragefile.h"
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#ifdef __linux__
# if HAVE_LINUX_MAGIC_H
# include <linux/magic.h>
# endif
# include <sys/statfs.h>
#endif
#include "dirname.h"
#include "viralloc.h"
#include "virerror.h"
#include "virlog.h"
#include "virfile.h"
#include "c-ctype.h"
#include "vircommand.h"
#include "virhash.h"
#include "virendian.h"
#define VIR_FROM_THIS VIR_FROM_STORAGE
VIR_ENUM_IMPL(virStorageFileFormat,
VIR_STORAGE_FILE_LAST,
"none",
"raw", "dir", "bochs",
"cloop", "cow", "dmg", "iso",
"qcow", "qcow2", "qed", "vmdk", "vpc",
"fat", "vhd", "vdi")
enum lv_endian {
LV_LITTLE_ENDIAN = 1, /* 1234 */
LV_BIG_ENDIAN /* 4321 */
};
enum {
BACKING_STORE_OK,
BACKING_STORE_INVALID,
BACKING_STORE_ERROR,
};
/* Either 'magic' or 'extension' *must* be provided */
struct FileTypeInfo {
int magicOffset; /* Byte offset of the magic */
const char *magic; /* Optional string of file magic
* to check at head of file */
const char *extension; /* Optional file extension to check */
enum lv_endian endian; /* Endianness of file format */
int versionOffset; /* Byte offset from start of file
* where we find version number,
* -1 to skip version test */
int versionNumber; /* Version number to validate */
int sizeOffset; /* Byte offset from start of file
* where we find capacity info,
* -1 to use st_size as capacity */
int sizeBytes; /* Number of bytes for size field */
int sizeMultiplier; /* A scaling factor if size is not in bytes */
/* Store a COW base image path (possibly relative),
* or NULL if there is no COW base image, to RES;
* return BACKING_STORE_* */
int qcowCryptOffset; /* Byte offset from start of file
* where to find encryption mode,
* -1 if encryption is not used */
int (*getBackingStore)(char **res, int *format,
const unsigned char *buf, size_t buf_size);
};
static int cowGetBackingStore(char **, int *,
const unsigned char *, size_t);
static int qcow1GetBackingStore(char **, int *,
const unsigned char *, size_t);
static int qcow2GetBackingStore(char **, int *,
const unsigned char *, size_t);
static int vmdk4GetBackingStore(char **, int *,
const unsigned char *, size_t);
static int
qedGetBackingStore(char **, int *, const unsigned char *, size_t);
#define QCOWX_HDR_VERSION (4)
#define QCOWX_HDR_BACKING_FILE_OFFSET (QCOWX_HDR_VERSION+4)
#define QCOWX_HDR_BACKING_FILE_SIZE (QCOWX_HDR_BACKING_FILE_OFFSET+8)
#define QCOWX_HDR_IMAGE_SIZE (QCOWX_HDR_BACKING_FILE_SIZE+4+4)
#define QCOW1_HDR_CRYPT (QCOWX_HDR_IMAGE_SIZE+8+1+1)
#define QCOW2_HDR_CRYPT (QCOWX_HDR_IMAGE_SIZE+8)
#define QCOW1_HDR_TOTAL_SIZE (QCOW1_HDR_CRYPT+4+8)
#define QCOW2_HDR_TOTAL_SIZE (QCOW2_HDR_CRYPT+4+4+8+8+4+4+8)
#define QCOW2_HDR_EXTENSION_END 0
#define QCOW2_HDR_EXTENSION_BACKING_FORMAT 0xE2792ACA
#define QED_HDR_FEATURES_OFFSET (4+4+4+4)
#define QED_HDR_IMAGE_SIZE (QED_HDR_FEATURES_OFFSET+8+8+8+8)
#define QED_HDR_BACKING_FILE_OFFSET (QED_HDR_IMAGE_SIZE+8)
#define QED_HDR_BACKING_FILE_SIZE (QED_HDR_BACKING_FILE_OFFSET+4)
#define QED_F_BACKING_FILE 0x01
#define QED_F_BACKING_FORMAT_NO_PROBE 0x04
/* VMDK needs at least 20*512 B to find backing store,
* ISO has 5 Byte magic on offset 32769,
* other formats need less */
#define STORAGE_MAX_HEAD 32769+5
static struct FileTypeInfo const fileTypeInfo[] = {
[VIR_STORAGE_FILE_NONE] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
-1, 0, 0, 0, 0, 0, NULL },
[VIR_STORAGE_FILE_RAW] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
-1, 0, 0, 0, 0, 0, NULL },
[VIR_STORAGE_FILE_DIR] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
-1, 0, 0, 0, 0, 0, NULL },
[VIR_STORAGE_FILE_BOCHS] = {
/*"Bochs Virtual HD Image", */ /* Untested */
0, NULL, NULL,
LV_LITTLE_ENDIAN, 64, 0x20000,
32+16+16+4+4+4+4+4, 8, 1, -1, NULL
},
[VIR_STORAGE_FILE_CLOOP] = {
/* #!/bin/sh
#V2.0 Format
modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1
*/ /* Untested */
0, NULL, NULL,
LV_LITTLE_ENDIAN, -1, 0,
-1, 0, 0, -1, NULL
},
[VIR_STORAGE_FILE_COW] = {
0, "OOOM", NULL,
LV_BIG_ENDIAN, 4, 2,
4+4+1024+4, 8, 1, -1, cowGetBackingStore
},
[VIR_STORAGE_FILE_DMG] = {
/* XXX QEMU says there's no magic for dmg,
* /usr/share/misc/magic lists double magic (both offsets
* would have to match) but then disables that check. */
0, NULL, ".dmg",
0, -1, 0,
-1, 0, 0, -1, NULL
},
[VIR_STORAGE_FILE_ISO] = {
32769, "CD001", ".iso",
LV_LITTLE_ENDIAN, -2, 0,
-1, 0, 0, -1, NULL
},
[VIR_STORAGE_FILE_QCOW] = {
0, "QFI", NULL,
LV_BIG_ENDIAN, 4, 1,
QCOWX_HDR_IMAGE_SIZE, 8, 1, QCOW1_HDR_CRYPT, qcow1GetBackingStore,
},
[VIR_STORAGE_FILE_QCOW2] = {
0, "QFI", NULL,
LV_BIG_ENDIAN, 4, 2,
QCOWX_HDR_IMAGE_SIZE, 8, 1, QCOW2_HDR_CRYPT, qcow2GetBackingStore,
},
[VIR_STORAGE_FILE_QED] = {
/* http://wiki.qemu.org/Features/QED */
0, "QED", NULL,
LV_LITTLE_ENDIAN, -2, -1,
QED_HDR_IMAGE_SIZE, 8, 1, -1, qedGetBackingStore,
},
[VIR_STORAGE_FILE_VMDK] = {
0, "KDMV", NULL,
LV_LITTLE_ENDIAN, 4, 1,
4+4+4, 8, 512, -1, vmdk4GetBackingStore
},
[VIR_STORAGE_FILE_VPC] = {
0, "conectix", NULL,
LV_BIG_ENDIAN, 12, 0x10000,
8 + 4 + 4 + 8 + 4 + 4 + 2 + 2 + 4, 8, 1, -1, NULL
},
/* TODO: add getBackingStore function */
[VIR_STORAGE_FILE_VDI] = {
64, "\x7f\x10\xda\xbe", ".vdi",
LV_LITTLE_ENDIAN, 68, 0x00010001,
64 + 5 * 4 + 256 + 7 * 4, 8, 1, -1, NULL},
/* Not direct file formats, but used for various drivers */
[VIR_STORAGE_FILE_FAT] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
-1, 0, 0, 0, 0, 0, NULL },
[VIR_STORAGE_FILE_VHD] = { 0, NULL, NULL, LV_LITTLE_ENDIAN,
-1, 0, 0, 0, 0, 0, NULL },
};
verify(ARRAY_CARDINALITY(fileTypeInfo) == VIR_STORAGE_FILE_LAST);
static int
cowGetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size)
{
#define COW_FILENAME_MAXLEN 1024
*res = NULL;
*format = VIR_STORAGE_FILE_AUTO;
if (buf_size < 4+4+ COW_FILENAME_MAXLEN)
return BACKING_STORE_INVALID;
if (buf[4+4] == '\0') { /* cow_header_v2.backing_file[0] */
*format = VIR_STORAGE_FILE_NONE;
return BACKING_STORE_OK;
}
*res = strndup((const char*)buf + 4+4, COW_FILENAME_MAXLEN);
if (*res == NULL) {
virReportOOMError();
return BACKING_STORE_ERROR;
}
return BACKING_STORE_OK;
}
static int
qcow2GetBackingStoreFormat(int *format,
const unsigned char *buf,
size_t buf_size,
size_t extension_start,
size_t extension_end)
{
size_t offset = extension_start;
/*
* The extensions take format of
*
* int32: magic
* int32: length
* byte[length]: payload
*
* Unknown extensions can be ignored by skipping
* over "length" bytes in the data stream.
*/
while (offset < (buf_size-8) &&
offset < (extension_end-8)) {
unsigned int magic = virReadBufInt32BE(buf + offset);
unsigned int len = virReadBufInt32BE(buf + offset + 4);
offset += 8;
if ((offset + len) < offset)
break;
if ((offset + len) > buf_size)
break;
switch (magic) {
case QCOW2_HDR_EXTENSION_END:
goto done;
case QCOW2_HDR_EXTENSION_BACKING_FORMAT:
if (buf[offset+len] != '\0')
break;
*format = virStorageFileFormatTypeFromString(
((const char *)buf)+offset);
if (*format <= VIR_STORAGE_FILE_NONE)
return -1;
}
offset += len;
}
done:
return 0;
}
static int
qcowXGetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size,
bool isQCow2)
{
unsigned long long offset;
unsigned int size;
*res = NULL;
if (format)
*format = VIR_STORAGE_FILE_AUTO;
if (buf_size < QCOWX_HDR_BACKING_FILE_OFFSET+8+4)
return BACKING_STORE_INVALID;
offset = virReadBufInt64BE(buf + QCOWX_HDR_BACKING_FILE_OFFSET);
if (offset > buf_size)
return BACKING_STORE_INVALID;
size = virReadBufInt32BE(buf + QCOWX_HDR_BACKING_FILE_SIZE);
if (size == 0) {
if (format)
*format = VIR_STORAGE_FILE_NONE;
return BACKING_STORE_OK;
}
if (offset + size > buf_size || offset + size < offset)
return BACKING_STORE_INVALID;
if (size + 1 == 0)
return BACKING_STORE_INVALID;
if (VIR_ALLOC_N(*res, size + 1) < 0) {
virReportOOMError();
return BACKING_STORE_ERROR;
}
memcpy(*res, buf + offset, size);
(*res)[size] = '\0';
/*
* Traditionally QCow2 files had a layout of
*
* [header]
* [backingStoreName]
*
* Although the backingStoreName typically followed
* the header immediately, this was not required by
* the format. By specifying a higher byte offset for
* the backing file offset in the header, it was
* possible to leave space between the header and
* start of backingStore.
*
* This hack is now used to store extensions to the
* qcow2 format:
*
* [header]
* [extensions]
* [backingStoreName]
*
* Thus the file region to search for extensions is
* between the end of the header (QCOW2_HDR_TOTAL_SIZE)
* and the start of the backingStoreName (offset)
*/
if (isQCow2 && format &&
qcow2GetBackingStoreFormat(format, buf, buf_size, QCOW2_HDR_TOTAL_SIZE,
offset) < 0)
return BACKING_STORE_INVALID;
return BACKING_STORE_OK;
}
static int
qcow1GetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size)
{
int ret;
/* QCow1 doesn't have the extensions capability
* used to store backing format */
*format = VIR_STORAGE_FILE_AUTO;
ret = qcowXGetBackingStore(res, NULL, buf, buf_size, false);
if (ret == 0 && *buf == '\0')
*format = VIR_STORAGE_FILE_NONE;
return ret;
}
static int
qcow2GetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size)
{
return qcowXGetBackingStore(res, format, buf, buf_size, true);
}
static int
vmdk4GetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size)
{
static const char prefix[] = "parentFileNameHint=\"";
char *desc, *start, *end;
size_t len;
int ret = BACKING_STORE_ERROR;
if (VIR_ALLOC_N(desc, STORAGE_MAX_HEAD + 1) < 0) {
virReportOOMError();
goto cleanup;
}
*res = NULL;
/*
* Technically this should have been VMDK, since
* VMDK spec / VMWare impl only support VMDK backed
* by VMDK. QEMU isn't following this though and
* does probing on VMDK backing files, hence we set
* AUTO
*/
*format = VIR_STORAGE_FILE_AUTO;
if (buf_size <= 0x200) {
ret = BACKING_STORE_INVALID;
goto cleanup;
}
len = buf_size - 0x200;
if (len > STORAGE_MAX_HEAD)
len = STORAGE_MAX_HEAD;
memcpy(desc, buf + 0x200, len);
desc[len] = '\0';
start = strstr(desc, prefix);
if (start == NULL) {
*format = VIR_STORAGE_FILE_NONE;
ret = BACKING_STORE_OK;
goto cleanup;
}
start += strlen(prefix);
end = strchr(start, '"');
if (end == NULL) {
ret = BACKING_STORE_INVALID;
goto cleanup;
}
if (end == start) {
*format = VIR_STORAGE_FILE_NONE;
ret = BACKING_STORE_OK;
goto cleanup;
}
*end = '\0';
*res = strdup(start);
if (*res == NULL) {
virReportOOMError();
goto cleanup;
}
ret = BACKING_STORE_OK;
cleanup:
VIR_FREE(desc);
return ret;
}
static int
qedGetBackingStore(char **res,
int *format,
const unsigned char *buf,
size_t buf_size)
{
unsigned long long flags;
unsigned long offset, size;
*res = NULL;
/* Check if this image has a backing file */
if (buf_size < QED_HDR_FEATURES_OFFSET+8)
return BACKING_STORE_INVALID;
flags = virReadBufInt64LE(buf + QED_HDR_FEATURES_OFFSET);
if (!(flags & QED_F_BACKING_FILE)) {
*format = VIR_STORAGE_FILE_NONE;
return BACKING_STORE_OK;
}
/* Parse the backing file */
if (buf_size < QED_HDR_BACKING_FILE_OFFSET+8)
return BACKING_STORE_INVALID;
offset = virReadBufInt32LE(buf + QED_HDR_BACKING_FILE_OFFSET);
if (offset > buf_size)
return BACKING_STORE_INVALID;
size = virReadBufInt32LE(buf + QED_HDR_BACKING_FILE_SIZE);
if (size == 0)
return BACKING_STORE_OK;
if (offset + size > buf_size || offset + size < offset)
return BACKING_STORE_INVALID;
if (VIR_ALLOC_N(*res, size + 1) < 0) {
virReportOOMError();
return BACKING_STORE_ERROR;
}
memcpy(*res, buf + offset, size);
(*res)[size] = '\0';
if (flags & QED_F_BACKING_FORMAT_NO_PROBE)
*format = VIR_STORAGE_FILE_RAW;
else
*format = VIR_STORAGE_FILE_AUTO_SAFE;
return BACKING_STORE_OK;
}
/**
* Given a starting point START (either an original file name, or the
* directory containing the original name, depending on START_IS_DIR)
* and a possibly relative backing file NAME, 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(3) ATTRIBUTE_NONNULL(5)
virFindBackingFile(const char *start, bool start_is_dir, const char *path,
char **directory, char **canonical)
{
char *combined = NULL;
int ret = -1;
if (*path == '/') {
/* Safe to cast away const */
combined = (char *)path;
} else {
size_t d_len = start_is_dir ? strlen(start) : dir_len(start);
if (d_len > INT_MAX) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("name too long: '%s'"), start);
goto cleanup;
} else if (d_len == 0) {
start = ".";
d_len = 1;
}
if (virAsprintf(&combined, "%.*s/%s", (int)d_len, start, path) < 0) {
virReportOOMError();
goto cleanup;
}
}
if (directory && !(*directory = mdir_name(combined))) {
virReportOOMError();
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,
unsigned char *buf,
size_t buflen)
{
int mlen;
int magicOffset = fileTypeInfo[format].magicOffset;
const char *magic = fileTypeInfo[format].magic;
if (magic == NULL)
return false;
/* Validate magic data */
mlen = strlen(magic);
if (magicOffset + mlen > buflen)
return false;
if (memcmp(buf + magicOffset, magic, mlen) != 0)
return false;
return true;
}
static bool
virStorageFileMatchesExtension(int format,
const char *path)
{
if (fileTypeInfo[format].extension == NULL)
return false;
if (virFileHasSuffix(path, fileTypeInfo[format].extension))
return true;
return false;
}
static bool
virStorageFileMatchesVersion(int format,
unsigned char *buf,
size_t buflen)
{
int version;
/* Validate version number info */
if (fileTypeInfo[format].versionOffset == -1)
return false;
/* -2 == non-versioned file format, so trivially match */
if (fileTypeInfo[format].versionOffset == -2)
return true;
if ((fileTypeInfo[format].versionOffset + 4) > buflen)
return false;
if (fileTypeInfo[format].endian == LV_LITTLE_ENDIAN)
version = virReadBufInt32LE(buf + fileTypeInfo[format].versionOffset);
else
version = virReadBufInt32BE(buf + fileTypeInfo[format].versionOffset);
VIR_DEBUG("Compare detected version %d vs expected version %d",
version, fileTypeInfo[format].versionNumber);
if (version != fileTypeInfo[format].versionNumber)
return false;
return true;
}
static bool
virBackingStoreIsFile(const char *backing)
{
/* Backing store is a network block device or Rados block device */
if (STRPREFIX(backing, "nbd:") || STRPREFIX(backing, "rbd:"))
return false;
return true;
}
static int
virStorageFileProbeFormatFromBuf(const char *path,
unsigned char *buf,
size_t buflen)
{
int format = VIR_STORAGE_FILE_RAW;
int i;
int possibleFormat = VIR_STORAGE_FILE_RAW;
VIR_DEBUG("path=%s", path);
/* First check file magic */
for (i = 0 ; i < VIR_STORAGE_FILE_LAST ; i++) {
if (virStorageFileMatchesMagic(i, buf, buflen)) {
if (!virStorageFileMatchesVersion(i, buf, buflen)) {
possibleFormat = i;
continue;
}
format = i;
goto cleanup;
}
}
if (possibleFormat != VIR_STORAGE_FILE_RAW)
VIR_WARN("File %s matches %s magic, but version is wrong. "
"Please report new version to libvir-list@redhat.com",
path, virStorageFileFormatTypeToString(possibleFormat));
/* No magic, so check file extension */
for (i = 0 ; i < VIR_STORAGE_FILE_LAST ; i++) {
if (virStorageFileMatchesExtension(i, path)) {
format = i;
goto cleanup;
}
}
cleanup:
VIR_DEBUG("format=%d", format);
return format;
}
/* Given a file descriptor FD open on PATH, and optionally opened from
* a given DIRECTORY, return metadata about that file, assuming it has
* the given FORMAT. */
static virStorageFileMetadataPtr
virStorageFileGetMetadataInternal(const char *path,
int fd,
const char *directory,
int format)
{
virStorageFileMetadata *meta = NULL;
unsigned char *buf = NULL;
ssize_t len = STORAGE_MAX_HEAD;
virStorageFileMetadata *ret = NULL;
struct stat sb;
VIR_DEBUG("path=%s, fd=%d, format=%d", path, fd, format);
if (VIR_ALLOC(meta) < 0) {
virReportOOMError();
return NULL;
}
if (fstat(fd, &sb) < 0) {
virReportSystemError(errno,
_("cannot stat file '%s'"),
path);
goto cleanup;
}
/* No header to probe for directories, but also no backing file */
if (S_ISDIR(sb.st_mode))
return meta;
if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
virReportSystemError(errno, _("cannot seek to start of '%s'"), path);
goto cleanup;
}
if (VIR_ALLOC_N(buf, len) < 0) {
virReportOOMError();
goto cleanup;
}
if ((len = read(fd, buf, len)) < 0) {
virReportSystemError(errno, _("cannot read header '%s'"), path);
goto cleanup;
}
if (format == VIR_STORAGE_FILE_AUTO)
format = virStorageFileProbeFormatFromBuf(path, buf, len);
if (format <= VIR_STORAGE_FILE_NONE ||
format >= VIR_STORAGE_FILE_LAST) {
virReportSystemError(EINVAL, _("unknown storage file format %d"),
format);
goto cleanup;
}
/* XXX we should consider moving virStorageBackendUpdateVolInfo
* code into this method, for non-magic files
*/
if (!fileTypeInfo[format].magic)
goto done;
/* Optionally extract capacity from file */
if (fileTypeInfo[format].sizeOffset != -1) {
if ((fileTypeInfo[format].sizeOffset + 8) > len)
goto done;
if (fileTypeInfo[format].endian == LV_LITTLE_ENDIAN)
meta->capacity = virReadBufInt64LE(buf +
fileTypeInfo[format].sizeOffset);
else
meta->capacity = virReadBufInt64BE(buf +
fileTypeInfo[format].sizeOffset);
/* Avoid unlikely, but theoretically possible overflow */
if (meta->capacity > (ULLONG_MAX /
fileTypeInfo[format].sizeMultiplier))
goto done;
meta->capacity *= fileTypeInfo[format].sizeMultiplier;
}
if (fileTypeInfo[format].qcowCryptOffset != -1) {
int crypt_format;
crypt_format = virReadBufInt32BE(buf +
fileTypeInfo[format].qcowCryptOffset);
meta->encrypted = crypt_format != 0;
}
if (fileTypeInfo[format].getBackingStore != NULL) {
char *backing;
int backingFormat;
int store = fileTypeInfo[format].getBackingStore(&backing,
&backingFormat,
buf, len);
if (store == BACKING_STORE_INVALID)
goto done;
if (store == BACKING_STORE_ERROR)
goto cleanup;
meta->backingStoreIsFile = false;
if (backing != NULL) {
meta->backingStore = strdup(backing);
if (meta->backingStore == NULL) {
virReportOOMError();
VIR_FREE(backing);
goto cleanup;
}
if (virBackingStoreIsFile(backing)) {
meta->backingStoreIsFile = true;
meta->backingStoreRaw = meta->backingStore;
meta->backingStore = NULL;
if (virFindBackingFile(directory ? directory : path,
!!directory, backing,
&meta->directory,
&meta->backingStore) < 0) {
/* the backing file is (currently) unavailable, treat this
* file as standalone:
* backingStoreRaw is kept to mark broken image chains */
meta->backingStoreIsFile = false;
backingFormat = VIR_STORAGE_FILE_NONE;
VIR_WARN("Backing file '%s' of image '%s' is missing.",
meta->backingStoreRaw, path);
}
}
VIR_FREE(backing);
meta->backingStoreFormat = backingFormat;
} else {
meta->backingStore = NULL;
meta->backingStoreFormat = VIR_STORAGE_FILE_NONE;
}
}
done:
ret = meta;
meta = NULL;
cleanup:
virStorageFileFreeMetadata(meta);
VIR_FREE(buf);
return ret;
}
/**
* virStorageFileProbeFormatFromFD:
*
* Probe for the format of 'fd' (which is an open file descriptor
* pointing to 'path'), returning the detected disk format.
*
* Callers are advised never to trust the returned 'format'
* unless it is listed as VIR_STORAGE_FILE_RAW, since a
* malicious guest can turn a file into any other non-raw
* format at will.
*
* Best option: Don't use this function
*/
int
virStorageFileProbeFormatFromFD(const char *path, int fd)
{
unsigned char *head;
ssize_t len = STORAGE_MAX_HEAD;
int ret = -1;
struct stat sb;
if (fstat(fd, &sb) < 0) {
virReportSystemError(errno,
_("cannot stat file '%s'"),
path);
return -1;
}
/* No header to probe for directories */
if (S_ISDIR(sb.st_mode)) {
return VIR_STORAGE_FILE_DIR;
}
if (VIR_ALLOC_N(head, len) < 0) {
virReportOOMError();
return -1;
}
if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
virReportSystemError(errno, _("cannot set to start of '%s'"), path);
goto cleanup;
}
if ((len = read(fd, head, len)) < 0) {
virReportSystemError(errno, _("cannot read header '%s'"), path);
goto cleanup;
}
ret = virStorageFileProbeFormatFromBuf(path, head, len);
cleanup:
VIR_FREE(head);
return ret;
}
/**
* virStorageFileProbeFormat:
*
* Probe for the format of 'path', returning the detected
* disk format.
*
* Callers are advised never to trust the returned 'format'
* unless it is listed as VIR_STORAGE_FILE_RAW, since a
* malicious guest can turn a raw file into any other non-raw
* format at will.
*
* Best option: Don't use this function
*/
int
virStorageFileProbeFormat(const char *path, uid_t uid, gid_t gid)
{
int fd, ret;
if ((fd = virFileOpenAs(path, O_RDONLY, 0, uid, gid, 0)) < 0) {
virReportSystemError(errno, _("cannot open file '%s'"), path);
return -1;
}
ret = virStorageFileProbeFormatFromFD(path, fd);
VIR_FORCE_CLOSE(fd);
return ret;
}
/**
* virStorageFileGetMetadataFromFD:
*
* 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. Does not recurse.
*
* 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.
*
* If the returned meta.backingStoreFormat is VIR_STORAGE_FILE_AUTO
* it indicates the image didn't specify an explicit format for its
* backing store. Callers are advised against probing for the
* backing store format in this case.
*
* Caller MUST free the result after use via virStorageFileFreeMetadata.
*/
virStorageFileMetadataPtr
virStorageFileGetMetadataFromFD(const char *path,
int fd,
int format)
{
return virStorageFileGetMetadataInternal(path, fd, NULL, format);
}
/* Recursive workhorse for virStorageFileGetMetadata. */
static virStorageFileMetadataPtr
virStorageFileGetMetadataRecurse(const char *path, const char *directory,
int format, uid_t uid, gid_t gid,
bool allow_probe, virHashTablePtr cycle)
{
int fd;
VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d",
path, format, (int)uid, (int)gid, allow_probe);
virStorageFileMetadataPtr ret = NULL;
if (virHashLookup(cycle, path)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("backing store for %s is self-referential"),
path);
return NULL;
}
if (virHashAddEntry(cycle, path, (void *)1) < 0)
return NULL;
if ((fd = virFileOpenAs(path, O_RDONLY, 0, uid, gid, 0)) < 0) {
virReportSystemError(-fd, _("cannot open file '%s'"), path);
return NULL;
}
ret = virStorageFileGetMetadataInternal(path, fd, directory, format);
if (VIR_CLOSE(fd) < 0)
VIR_WARN("could not close file %s", path);
if (ret && ret->backingStoreIsFile) {
if (ret->backingStoreFormat == VIR_STORAGE_FILE_AUTO && !allow_probe)
ret->backingStoreFormat = VIR_STORAGE_FILE_RAW;
else if (ret->backingStoreFormat == VIR_STORAGE_FILE_AUTO_SAFE)
ret->backingStoreFormat = VIR_STORAGE_FILE_AUTO;
format = ret->backingStoreFormat;
ret->backingMeta = virStorageFileGetMetadataRecurse(ret->backingStore,
ret->directory,
format,
uid, gid,
allow_probe,
cycle);
}
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.
*
* If the returned meta.backingStoreFormat is VIR_STORAGE_FILE_AUTO
* it indicates the image didn't specify an explicit format for its
* backing store. Callers are advised against using ALLOW_PROBE, as
* it would probe the backing store format in this case.
*
* Caller MUST free result after use via virStorageFileFreeMetadata.
*/
virStorageFileMetadataPtr
virStorageFileGetMetadata(const char *path, int format,
uid_t uid, gid_t gid,
bool allow_probe)
{
VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d",
path, format, (int)uid, (int)gid, allow_probe);
virHashTablePtr cycle = virHashCreate(5, NULL);
virStorageFileMetadataPtr ret;
if (!cycle)
return NULL;
if (format <= VIR_STORAGE_FILE_NONE)
format = allow_probe ? VIR_STORAGE_FILE_AUTO : VIR_STORAGE_FILE_RAW;
ret = virStorageFileGetMetadataRecurse(path, NULL, format, uid, gid,
allow_probe, cycle);
virHashFree(cycle);
return ret;
}
/**
* virStorageFileFreeMetadata:
*
* Free pointers in passed structure and structure itself.
*/
void
virStorageFileFreeMetadata(virStorageFileMetadata *meta)
{
if (!meta)
return;
virStorageFileFreeMetadata(meta->backingMeta);
VIR_FREE(meta->backingStore);
VIR_FREE(meta->backingStoreRaw);
VIR_FREE(meta->directory);
VIR_FREE(meta);
}
/**
* virStorageFileResize:
*
* Change the capacity of the raw storage file at 'path'.
*/
int
virStorageFileResize(const char *path, unsigned long long capacity)
{
int fd = -1;
int ret = -1;
if ((fd = open(path, O_RDWR)) < 0) {
virReportSystemError(errno, _("Unable to open '%s'"), path);
goto cleanup;
}
if (ftruncate(fd, capacity) < 0) {
virReportSystemError(errno, _("Failed to truncate file '%s'"), path);
goto cleanup;
}
if (VIR_CLOSE(fd) < 0) {
virReportSystemError(errno, _("Unable to save '%s'"), path);
goto cleanup;
}
ret = 0;
cleanup:
VIR_FORCE_CLOSE(fd);
return ret;
}
#ifdef __linux__
# ifndef NFS_SUPER_MAGIC
# define NFS_SUPER_MAGIC 0x6969
# endif
# ifndef OCFS2_SUPER_MAGIC
# define OCFS2_SUPER_MAGIC 0x7461636f
# endif
# ifndef GFS2_MAGIC
# define GFS2_MAGIC 0x01161970
# endif
# ifndef AFS_FS_MAGIC
# define AFS_FS_MAGIC 0x6B414653
# endif
int virStorageFileIsSharedFSType(const char *path,
int fstypes)
{
char *dirpath, *p;
struct statfs sb;
int statfs_ret;
if ((dirpath = strdup(path)) == NULL) {
virReportOOMError();
return -1;
}
do {
/* Try less and less of the path until we get to a
* directory we can stat. Even if we don't have 'x'
* permission on any directory in the path on the NFS
* server (assuming it's NFS), we will be able to stat the
* mount point, and that will properly tell us if the
* fstype is NFS.
*/
if ((p = strrchr(dirpath, '/')) == NULL) {
virReportSystemError(EINVAL,
_("Invalid relative path '%s'"), path);
VIR_FREE(dirpath);
return -1;
}
if (p == dirpath)
*(p+1) = '\0';
else
*p = '\0';
statfs_ret = statfs(dirpath, &sb);
} while ((statfs_ret < 0) && (p != dirpath));
VIR_FREE(dirpath);
if (statfs_ret < 0) {
virReportSystemError(errno,
_("cannot determine filesystem for '%s'"),
path);
return -1;
}
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
path, (long long int)sb.f_type);
if ((fstypes & VIR_STORAGE_FILE_SHFS_NFS) &&
(sb.f_type == NFS_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_STORAGE_FILE_SHFS_GFS2) &&
(sb.f_type == GFS2_MAGIC))
return 1;
if ((fstypes & VIR_STORAGE_FILE_SHFS_OCFS) &&
(sb.f_type == OCFS2_SUPER_MAGIC))
return 1;
if ((fstypes & VIR_STORAGE_FILE_SHFS_AFS) &&
(sb.f_type == AFS_FS_MAGIC))
return 1;
return 0;
}
#else
int virStorageFileIsSharedFSType(const char *path ATTRIBUTE_UNUSED,
int fstypes ATTRIBUTE_UNUSED)
{
/* XXX implement me :-) */
return 0;
}
#endif
int virStorageFileIsSharedFS(const char *path)
{
return virStorageFileIsSharedFSType(path,
VIR_STORAGE_FILE_SHFS_NFS |
VIR_STORAGE_FILE_SHFS_GFS2 |
VIR_STORAGE_FILE_SHFS_OCFS |
VIR_STORAGE_FILE_SHFS_AFS);
}
int virStorageFileIsClusterFS(const char *path)
{
/* These are coherent cluster filesystems known to be safe for
* migration with cache != none
*/
return virStorageFileIsSharedFSType(path,
VIR_STORAGE_FILE_SHFS_GFS2 |
VIR_STORAGE_FILE_SHFS_OCFS);
}
#ifdef LVS
int virStorageFileGetLVMKey(const char *path,
char **key)
{
/*
* # lvs --noheadings --unbuffered --nosuffix --options "uuid" LVNAME
* 06UgP5-2rhb-w3Bo-3mdR-WeoL-pytO-SAa2ky
*/
int status;
virCommandPtr cmd = virCommandNewArgList(
LVS,
"--noheadings", "--unbuffered", "--nosuffix",
"--options", "uuid", path,
NULL
);
int ret = -1;
*key = NULL;
/* Run the program and capture its output */
virCommandSetOutputBuffer(cmd, key);
if (virCommandRun(cmd, &status) < 0)
goto cleanup;
/* Explicitly check status == 0, rather than passing NULL
* to virCommandRun because we don't want to raise an actual
* error in this scenario, just return a NULL key.
*/
if (status == 0 && *key) {
char *nl;
char *tmp = *key;
/* Find first non-space character */
while (*tmp && c_isspace(*tmp)) {
tmp++;
}
/* Kill leading spaces */
if (tmp != *key)
memmove(*key, tmp, strlen(tmp)+1);
/* Kill trailing newline */
if ((nl = strchr(*key, '\n')))
*nl = '\0';
}
ret = 0;
cleanup:
if (*key && STREQ(*key, ""))
VIR_FREE(*key);
virCommandFree(cmd);
return ret;
}
#else
int virStorageFileGetLVMKey(const char *path,
char **key ATTRIBUTE_UNUSED)
{
virReportSystemError(ENOSYS, _("Unable to get LVM key for %s"), path);
return -1;
}
#endif
#ifdef WITH_UDEV
int virStorageFileGetSCSIKey(const char *path,
char **key)
{
int status;
virCommandPtr cmd = virCommandNewArgList(
"/lib/udev/scsi_id",
"--replace-whitespace",
"--whitelisted",
"--device", path,
NULL
);
int ret = -1;
*key = NULL;
/* Run the program and capture its output */
virCommandSetOutputBuffer(cmd, key);
if (virCommandRun(cmd, &status) < 0)
goto cleanup;
/* Explicitly check status == 0, rather than passing NULL
* to virCommandRun because we don't want to raise an actual
* error in this scenario, just return a NULL key.
*/
if (status == 0 && *key) {
char *nl = strchr(*key, '\n');
if (nl)
*nl = '\0';
}
ret = 0;
cleanup:
if (*key && STREQ(*key, ""))
VIR_FREE(*key);
virCommandFree(cmd);
return ret;
}
#else
int virStorageFileGetSCSIKey(const char *path,
char **key ATTRIBUTE_UNUSED)
{
virReportSystemError(ENOSYS, _("Unable to get SCSI key for %s"), path);
return -1;
}
#endif
/* Given a CHAIN that starts at the named file START, return a string
* pointing to either START or within CHAIN that gives the preferred
* name for the backing file NAME within that chain. Pass NULL for
* NAME to find the base of the chain. If META is not NULL, set *META
* to the point in the chain that describes NAME (or to NULL if the
* backing element is not a file). If PARENT is not NULL, set *PARENT
* to the preferred name of the parent (or to NULL if NAME matches
* START). Since the results point within CHAIN, they must not be
* independently freed. */
const char *
virStorageFileChainLookup(virStorageFileMetadataPtr chain, const char *start,
const char *name, virStorageFileMetadataPtr *meta,
const char **parent)
{
virStorageFileMetadataPtr owner;
const char *tmp;
if (!parent)
parent = &tmp;
*parent = NULL;
if (name ? STREQ(start, name) || virFileLinkPointsTo(start, name) :
!chain->backingStore) {
if (meta)
*meta = chain;
return start;
}
owner = chain;
*parent = start;
while (owner) {
if (!owner->backingStore)
goto error;
if (!name) {
if (!owner->backingMeta ||
!owner->backingMeta->backingStore)
break;
} else if (STREQ_NULLABLE(name, owner->backingStoreRaw) ||
STREQ(name, owner->backingStore)) {
break;
} else if (owner->backingStoreIsFile) {
char *absName = NULL;
if (virFindBackingFile(owner->directory, true, name,
NULL, &absName) < 0)
goto error;
if (absName && STREQ(absName, owner->backingStore)) {
VIR_FREE(absName);
break;
}
VIR_FREE(absName);
}
*parent = owner->backingStore;
owner = owner->backingMeta;
}
if (!owner)
goto error;
if (meta)
*meta = owner->backingMeta;
return owner->backingStore;
error:
*parent = NULL;
if (meta)
*meta = NULL;
return NULL;
}
Reference in New Issue View Git Blame Copy Permalink