[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[libvirt] Re: [PATCH 4/6] Move virStorageGetMetadataFromFD() to libvirt_util



On Tue, Sep 29, 2009 at 09:56:47AM +0100, Mark McLoughlin wrote:
> Finally, we get to the point of all this.
> 
> Move virStorageGetMetadataFromFD() to virStorageFileGetMetadataFromFD()
> and move to src/util/storage_file.[ch]
> 
> There's no functional changes in this patch, just code movement
> 
> * src/storage/storage_backend_fs.c: move code from here ...
> 
> * src/util/storage_file.[ch]: ... to here
> 
> * src/libvirt_private.syms: export virStorageFileGetMetadataFromFD()
> ---
>  src/libvirt_private.syms         |    1 +
>  src/storage/storage_backend_fs.c |  368 +-------------------------------------
>  src/util/storage_file.c          |  373 ++++++++++++++++++++++++++++++++++++++
>  src/util/storage_file.h          |    5 +
>  4 files changed, 380 insertions(+), 367 deletions(-)
> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index ddab21d..4890032 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -393,6 +393,7 @@ virStorageGenerateQcowPassphrase;
>  # storage_file.h
>  virStorageFileFormatTypeToString;
>  virStorageFileFormatTypeFromString;
> +virStorageFileGetMetadataFromFD;
>  
>  # threads.h
>  virMutexInit;
> diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
> index 7db73bf..6816da8 100644
> --- a/src/storage/storage_backend_fs.c
> +++ b/src/storage/storage_backend_fs.c
> @@ -46,375 +46,9 @@
>  #include "memory.h"
>  #include "xml.h"
>  
> -enum lv_endian {
> -    LV_LITTLE_ENDIAN = 1, /* 1234 */
> -    LV_BIG_ENDIAN         /* 4321 */
> -};
> -
> -enum {
> -    BACKING_STORE_OK,
> -    BACKING_STORE_INVALID,
> -    BACKING_STORE_ERROR,
> -};
> -
> -static int cowGetBackingStore(virConnectPtr, char **,
> -                              const unsigned char *, size_t);
> -static int qcowXGetBackingStore(virConnectPtr, char **,
> -                                const unsigned char *, size_t);
> -static int vmdk4GetBackingStore(virConnectPtr, char **,
> -                                const unsigned char *, size_t);
> -
> -/* Either 'magic' or 'extension' *must* be provided */
> -struct FileTypeInfo {
> -    int type;           /* One of the constants above */
> -    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)(virConnectPtr conn, char **res,
> -                           const unsigned char *buf, size_t buf_size);
> -};
> -struct FileTypeInfo const fileTypeInfo[] = {
> -    /* Bochs */
> -    /* XXX Untested
> -    { VIR_STORAGE_FILE_BOCHS, "Bochs Virtual HD Image", NULL,
> -      LV_LITTLE_ENDIAN, 64, 0x20000,
> -      32+16+16+4+4+4+4+4, 8, 1, -1, NULL },*/
> -    /* CLoop */
> -    /* XXX Untested
> -    { VIR_STORAGE_VOL_CLOOP, "#!/bin/sh\n#V2.0 Format\nmodprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n", NULL,
> -      LV_LITTLE_ENDIAN, -1, 0,
> -      -1, 0, 0, -1, NULL }, */
> -    /* Cow */
> -    { VIR_STORAGE_FILE_COW, "OOOM", NULL,
> -      LV_BIG_ENDIAN, 4, 2,
> -      4+4+1024+4, 8, 1, -1, cowGetBackingStore },
> -    /* DMG */
> -    /* XXX QEMU says there's no magic for dmg, but we should check... */
> -    { VIR_STORAGE_FILE_DMG, NULL, ".dmg",
> -      0, -1, 0,
> -      -1, 0, 0, -1, NULL },
> -    /* XXX there's probably some magic for iso we can validate too... */
> -    { VIR_STORAGE_FILE_ISO, NULL, ".iso",
> -      0, -1, 0,
> -      -1, 0, 0, -1, NULL },
> -    /* Parallels */
> -    /* XXX Untested
> -    { VIR_STORAGE_FILE_PARALLELS, "WithoutFreeSpace", NULL,
> -      LV_LITTLE_ENDIAN, 16, 2,
> -      16+4+4+4+4, 4, 512, -1, NULL },
> -    */
> -    /* QCow */
> -    { VIR_STORAGE_FILE_QCOW, "QFI", NULL,
> -      LV_BIG_ENDIAN, 4, 1,
> -      4+4+8+4+4, 8, 1, 4+4+8+4+4+8+1+1+2, qcowXGetBackingStore },
> -    /* QCow 2 */
> -    { VIR_STORAGE_FILE_QCOW2, "QFI", NULL,
> -      LV_BIG_ENDIAN, 4, 2,
> -      4+4+8+4+4, 8, 1, 4+4+8+4+4+8, qcowXGetBackingStore },
> -    /* VMDK 3 */
> -    /* XXX Untested
> -    { VIR_STORAGE_FILE_VMDK, "COWD", NULL,
> -      LV_LITTLE_ENDIAN, 4, 1,
> -      4+4+4, 4, 512, -1, NULL },
> -    */
> -    /* VMDK 4 */
> -    { VIR_STORAGE_FILE_VMDK, "KDMV", NULL,
> -      LV_LITTLE_ENDIAN, 4, 1,
> -      4+4+4, 8, 512, -1, vmdk4GetBackingStore },
> -    /* Connectix / VirtualPC */
> -    /* XXX Untested
> -    { VIR_STORAGE_FILE_VPC, "conectix", NULL,
> -      LV_BIG_ENDIAN, -1, 0,
> -      -1, 0, 0, -1, NULL},
> -    */
> -};
> -
>  #define VIR_FROM_THIS VIR_FROM_STORAGE
>  
>  static int
> -cowGetBackingStore(virConnectPtr conn,
> -                   char **res,
> -                   const unsigned char *buf,
> -                   size_t buf_size)
> -{
> -#define COW_FILENAME_MAXLEN 1024
> -    *res = NULL;
> -    if (buf_size < 4+4+ COW_FILENAME_MAXLEN)
> -        return BACKING_STORE_INVALID;
> -    if (buf[4+4] == '\0') /* cow_header_v2.backing_file[0] */
> -        return BACKING_STORE_OK;
> -
> -    *res = strndup ((const char*)buf + 4+4, COW_FILENAME_MAXLEN);
> -    if (*res == NULL) {
> -        virReportOOMError(conn);
> -        return BACKING_STORE_ERROR;
> -    }
> -    return BACKING_STORE_OK;
> -}
> -
> -static int
> -qcowXGetBackingStore(virConnectPtr conn,
> -                     char **res,
> -                     const unsigned char *buf,
> -                     size_t buf_size)
> -{
> -    unsigned long long offset;
> -    unsigned long size;
> -
> -    *res = NULL;
> -    if (buf_size < 4+4+8+4)
> -        return BACKING_STORE_INVALID;
> -    offset = (((unsigned long long)buf[4+4] << 56)
> -              | ((unsigned long long)buf[4+4+1] << 48)
> -              | ((unsigned long long)buf[4+4+2] << 40)
> -              | ((unsigned long long)buf[4+4+3] << 32)
> -              | ((unsigned long long)buf[4+4+4] << 24)
> -              | ((unsigned long long)buf[4+4+5] << 16)
> -              | ((unsigned long long)buf[4+4+6] << 8)
> -              | buf[4+4+7]); /* QCowHeader.backing_file_offset */
> -    if (offset > buf_size)
> -        return BACKING_STORE_INVALID;
> -    size = ((buf[4+4+8] << 24)
> -            | (buf[4+4+8+1] << 16)
> -            | (buf[4+4+8+2] << 8)
> -            | buf[4+4+8+3]); /* QCowHeader.backing_file_size */
> -    if (size == 0)
> -        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(conn);
> -        return BACKING_STORE_ERROR;
> -    }
> -    memcpy(*res, buf + offset, size);
> -    (*res)[size] = '\0';
> -    return BACKING_STORE_OK;
> -}
> -
> -
> -static int
> -vmdk4GetBackingStore(virConnectPtr conn,
> -                     char **res,
> -                     const unsigned char *buf,
> -                     size_t buf_size)
> -{
> -    static const char prefix[] = "parentFileNameHint=\"";
> -
> -    char desc[20*512 + 1], *start, *end;
> -    size_t len;
> -
> -    *res = NULL;
> -
> -    if (buf_size <= 0x200)
> -        return BACKING_STORE_INVALID;
> -    len = buf_size - 0x200;
> -    if (len > sizeof(desc) - 1)
> -        len = sizeof(desc) - 1;
> -    memcpy(desc, buf + 0x200, len);
> -    desc[len] = '\0';
> -    start = strstr(desc, prefix);
> -    if (start == NULL)
> -        return BACKING_STORE_OK;
> -    start += strlen(prefix);
> -    end = strchr(start, '"');
> -    if (end == NULL)
> -        return BACKING_STORE_INVALID;
> -    if (end == start)
> -        return BACKING_STORE_OK;
> -    *end = '\0';
> -    *res = strdup(start);
> -    if (*res == NULL) {
> -        virReportOOMError(conn);
> -        return BACKING_STORE_ERROR;
> -    }
> -    return BACKING_STORE_OK;
> -}
> -
> -/**
> - * Return an absolute path corresponding to PATH, which is absolute or relative
> - * to the directory containing BASE_FILE, or NULL on error
> - */
> -static char *absolutePathFromBaseFile(const char *base_file, const char *path)
> -{
> -    size_t base_size, path_size;
> -    char *res, *p;
> -
> -    if (*path == '/')
> -        return strdup(path);
> -
> -    base_size = strlen(base_file) + 1;
> -    path_size = strlen(path) + 1;
> -    if (VIR_ALLOC_N(res, base_size - 1 + path_size) < 0)
> -        return NULL;
> -    memcpy(res, base_file, base_size);
> -    p = strrchr(res, '/');
> -    if (p != NULL)
> -        p++;
> -    else
> -        p = res;
> -    memcpy(p, path, path_size);
> -    if (VIR_REALLOC_N(res, (p + path_size) - res) < 0) {
> -        /* Ignore failure */
> -    }
> -    return res;
> -}
> -
> -
> -
> -/**
> - * Probe the header of a file to determine what type of disk image
> - * it is, and info about its capacity if available.
> - */
> -static int
> -virStorageGetMetadataFromFD(virConnectPtr conn,
> -                            const char *path,
> -                            int fd,
> -                            virStorageFileMetadata *meta)
> -{
> -    unsigned char head[20*512]; /* vmdk4GetBackingStore needs this much. */
> -    int len, i;
> -
> -    /* If all else fails, call it a raw file */
> -    meta->format = VIR_STORAGE_FILE_RAW;
> -
> -    if ((len = read(fd, head, sizeof(head))) < 0) {
> -        virReportSystemError(conn, errno, _("cannot read header '%s'"), path);
> -        return -1;
> -    }
> -
> -    /* First check file magic */
> -    for (i = 0 ; i < ARRAY_CARDINALITY(fileTypeInfo) ; i++) {
> -        int mlen;
> -
> -        if (fileTypeInfo[i].magic == NULL)
> -            continue;
> -
> -        /* Validate magic data */
> -        mlen = strlen(fileTypeInfo[i].magic);
> -        if (mlen > len)
> -            continue;
> -        if (memcmp(head, fileTypeInfo[i].magic, mlen) != 0)
> -            continue;
> -
> -        /* Validate version number info */
> -        if (fileTypeInfo[i].versionNumber != -1) {
> -            int version;
> -
> -            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
> -                version = (head[fileTypeInfo[i].versionOffset+3] << 24) |
> -                    (head[fileTypeInfo[i].versionOffset+2] << 16) |
> -                    (head[fileTypeInfo[i].versionOffset+1] << 8) |
> -                    head[fileTypeInfo[i].versionOffset];
> -            } else {
> -                version = (head[fileTypeInfo[i].versionOffset] << 24) |
> -                    (head[fileTypeInfo[i].versionOffset+1] << 16) |
> -                    (head[fileTypeInfo[i].versionOffset+2] << 8) |
> -                    head[fileTypeInfo[i].versionOffset+3];
> -            }
> -            if (version != fileTypeInfo[i].versionNumber)
> -                continue;
> -        }
> -
> -        /* Optionally extract capacity from file */
> -        if (fileTypeInfo[i].sizeOffset != -1) {
> -            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
> -                meta->capacity =
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+7] << 56) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+6] << 48) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+5] << 40) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+4] << 32) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+3] << 24) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+2] << 16) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+1] << 8) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset]);
> -            } else {
> -                meta->capacity =
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset] << 56) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+1] << 48) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+2] << 40) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+3] << 32) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+4] << 24) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+5] << 16) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+6] << 8) |
> -                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+7]);
> -            }
> -            /* Avoid unlikely, but theoretically possible overflow */
> -            if (meta->capacity > (ULLONG_MAX / fileTypeInfo[i].sizeMultiplier))
> -                continue;
> -            meta->capacity *= fileTypeInfo[i].sizeMultiplier;
> -        }
> -
> -        if (fileTypeInfo[i].qcowCryptOffset != -1) {
> -            int crypt_format;
> -
> -            crypt_format = (head[fileTypeInfo[i].qcowCryptOffset] << 24) |
> -                (head[fileTypeInfo[i].qcowCryptOffset+1] << 16) |
> -                (head[fileTypeInfo[i].qcowCryptOffset+2] << 8) |
> -                head[fileTypeInfo[i].qcowCryptOffset+3];
> -            meta->encrypted = crypt_format != 0;
> -        }
> -
> -        /* Validation passed, we know the file format now */
> -        meta->format = fileTypeInfo[i].type;
> -        if (fileTypeInfo[i].getBackingStore != NULL) {
> -            char *base;
> -
> -            switch (fileTypeInfo[i].getBackingStore(conn, &base, head, len)) {
> -            case BACKING_STORE_OK:
> -                break;
> -
> -            case BACKING_STORE_INVALID:
> -                continue;
> -
> -            case BACKING_STORE_ERROR:
> -                return -1;
> -            }
> -            if (base != NULL) {
> -                meta->backingStore = absolutePathFromBaseFile(path, base);
> -                VIR_FREE(base);
> -                if (meta->backingStore == NULL) {
> -                    virReportOOMError(conn);
> -                    return -1;
> -                }
> -            }
> -        }
> -        return 0;
> -    }
> -
> -    /* No magic, so check file extension */
> -    for (i = 0 ; i < ARRAY_CARDINALITY(fileTypeInfo) ; i++) {
> -        if (fileTypeInfo[i].extension == NULL)
> -            continue;
> -
> -        if (!virFileHasSuffix(path, fileTypeInfo[i].extension))
> -            continue;
> -
> -        meta->format = fileTypeInfo[i].type;
> -        return 0;
> -    }
> -
> -    return 0;
> -}
> -
> -static int
>  virStorageBackendProbeTarget(virConnectPtr conn,
>                               virStorageVolTargetPtr target,
>                               char **backingStore,
> @@ -444,7 +78,7 @@ virStorageBackendProbeTarget(virConnectPtr conn,
>  
>      memset(&meta, 0, sizeof(meta));
>  
> -    if (virStorageGetMetadataFromFD(conn, target->path, fd, &meta) < 0) {
> +    if (virStorageFileGetMetadataFromFD(conn, target->path, fd, &meta) < 0) {
>          close(fd);
>          return -1;
>      }
> diff --git a/src/util/storage_file.c b/src/util/storage_file.c
> index e66ec8a..e674713 100644
> --- a/src/util/storage_file.c
> +++ b/src/util/storage_file.c
> @@ -24,8 +24,381 @@
>  #include <config.h>
>  #include "storage_file.h"
>  
> +#include <unistd.h>
> +#include "memory.h"
> +#include "virterror_internal.h"
> +
> +#define VIR_FROM_THIS VIR_FROM_STORAGE
> +
>  VIR_ENUM_IMPL(virStorageFileFormat,
>                VIR_STORAGE_FILE_LAST,
>                "raw", "dir", "bochs",
>                "cloop", "cow", "dmg", "iso",
>                "qcow", "qcow2", "vmdk", "vpc")
> +
> +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 type;           /* One of the constants above */
> +    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)(virConnectPtr conn, char **res,
> +                           const unsigned char *buf, size_t buf_size);
> +};
> +
> +static int cowGetBackingStore(virConnectPtr, char **,
> +                              const unsigned char *, size_t);
> +static int qcowXGetBackingStore(virConnectPtr, char **,
> +                                const unsigned char *, size_t);
> +static int vmdk4GetBackingStore(virConnectPtr, char **,
> +                                const unsigned char *, size_t);
> +
> +
> +static struct FileTypeInfo const fileTypeInfo[] = {
> +    /* Bochs */
> +    /* XXX Untested
> +    { VIR_STORAGE_FILE_BOCHS, "Bochs Virtual HD Image", NULL,
> +      LV_LITTLE_ENDIAN, 64, 0x20000,
> +      32+16+16+4+4+4+4+4, 8, 1, -1, NULL },*/
> +    /* CLoop */
> +    /* XXX Untested
> +    { VIR_STORAGE_VOL_CLOOP, "#!/bin/sh\n#V2.0 Format\nmodprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n", NULL,
> +      LV_LITTLE_ENDIAN, -1, 0,
> +      -1, 0, 0, -1, NULL }, */
> +    /* Cow */
> +    { VIR_STORAGE_FILE_COW, "OOOM", NULL,
> +      LV_BIG_ENDIAN, 4, 2,
> +      4+4+1024+4, 8, 1, -1, cowGetBackingStore },
> +    /* DMG */
> +    /* XXX QEMU says there's no magic for dmg, but we should check... */
> +    { VIR_STORAGE_FILE_DMG, NULL, ".dmg",
> +      0, -1, 0,
> +      -1, 0, 0, -1, NULL },
> +    /* XXX there's probably some magic for iso we can validate too... */
> +    { VIR_STORAGE_FILE_ISO, NULL, ".iso",
> +      0, -1, 0,
> +      -1, 0, 0, -1, NULL },
> +    /* Parallels */
> +    /* XXX Untested
> +    { VIR_STORAGE_FILE_PARALLELS, "WithoutFreeSpace", NULL,
> +      LV_LITTLE_ENDIAN, 16, 2,
> +      16+4+4+4+4, 4, 512, -1, NULL },
> +    */
> +    /* QCow */
> +    { VIR_STORAGE_FILE_QCOW, "QFI", NULL,
> +      LV_BIG_ENDIAN, 4, 1,
> +      4+4+8+4+4, 8, 1, 4+4+8+4+4+8+1+1+2, qcowXGetBackingStore },
> +    /* QCow 2 */
> +    { VIR_STORAGE_FILE_QCOW2, "QFI", NULL,
> +      LV_BIG_ENDIAN, 4, 2,
> +      4+4+8+4+4, 8, 1, 4+4+8+4+4+8, qcowXGetBackingStore },
> +    /* VMDK 3 */
> +    /* XXX Untested
> +    { VIR_STORAGE_FILE_VMDK, "COWD", NULL,
> +      LV_LITTLE_ENDIAN, 4, 1,
> +      4+4+4, 4, 512, -1, NULL },
> +    */
> +    /* VMDK 4 */
> +    { VIR_STORAGE_FILE_VMDK, "KDMV", NULL,
> +      LV_LITTLE_ENDIAN, 4, 1,
> +      4+4+4, 8, 512, -1, vmdk4GetBackingStore },
> +    /* Connectix / VirtualPC */
> +    /* XXX Untested
> +    { VIR_STORAGE_FILE_VPC, "conectix", NULL,
> +      LV_BIG_ENDIAN, -1, 0,
> +      -1, 0, 0, -1, NULL},
> +    */
> +};
> +
> +static int
> +cowGetBackingStore(virConnectPtr conn,
> +                   char **res,
> +                   const unsigned char *buf,
> +                   size_t buf_size)
> +{
> +#define COW_FILENAME_MAXLEN 1024
> +    *res = NULL;
> +    if (buf_size < 4+4+ COW_FILENAME_MAXLEN)
> +        return BACKING_STORE_INVALID;
> +    if (buf[4+4] == '\0') /* cow_header_v2.backing_file[0] */
> +        return BACKING_STORE_OK;
> +
> +    *res = strndup ((const char*)buf + 4+4, COW_FILENAME_MAXLEN);
> +    if (*res == NULL) {
> +        virReportOOMError(conn);
> +        return BACKING_STORE_ERROR;
> +    }
> +    return BACKING_STORE_OK;
> +}
> +
> +static int
> +qcowXGetBackingStore(virConnectPtr conn,
> +                     char **res,
> +                     const unsigned char *buf,
> +                     size_t buf_size)
> +{
> +    unsigned long long offset;
> +    unsigned long size;
> +
> +    *res = NULL;
> +    if (buf_size < 4+4+8+4)
> +        return BACKING_STORE_INVALID;
> +    offset = (((unsigned long long)buf[4+4] << 56)
> +              | ((unsigned long long)buf[4+4+1] << 48)
> +              | ((unsigned long long)buf[4+4+2] << 40)
> +              | ((unsigned long long)buf[4+4+3] << 32)
> +              | ((unsigned long long)buf[4+4+4] << 24)
> +              | ((unsigned long long)buf[4+4+5] << 16)
> +              | ((unsigned long long)buf[4+4+6] << 8)
> +              | buf[4+4+7]); /* QCowHeader.backing_file_offset */
> +    if (offset > buf_size)
> +        return BACKING_STORE_INVALID;
> +    size = ((buf[4+4+8] << 24)
> +            | (buf[4+4+8+1] << 16)
> +            | (buf[4+4+8+2] << 8)
> +            | buf[4+4+8+3]); /* QCowHeader.backing_file_size */
> +    if (size == 0)
> +        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(conn);
> +        return BACKING_STORE_ERROR;
> +    }
> +    memcpy(*res, buf + offset, size);
> +    (*res)[size] = '\0';
> +    return BACKING_STORE_OK;
> +}
> +
> +
> +static int
> +vmdk4GetBackingStore(virConnectPtr conn,
> +                     char **res,
> +                     const unsigned char *buf,
> +                     size_t buf_size)
> +{
> +    static const char prefix[] = "parentFileNameHint=\"";
> +
> +    char desc[20*512 + 1], *start, *end;
> +    size_t len;
> +
> +    *res = NULL;
> +
> +    if (buf_size <= 0x200)
> +        return BACKING_STORE_INVALID;
> +    len = buf_size - 0x200;
> +    if (len > sizeof(desc) - 1)
> +        len = sizeof(desc) - 1;
> +    memcpy(desc, buf + 0x200, len);
> +    desc[len] = '\0';
> +    start = strstr(desc, prefix);
> +    if (start == NULL)
> +        return BACKING_STORE_OK;
> +    start += strlen(prefix);
> +    end = strchr(start, '"');
> +    if (end == NULL)
> +        return BACKING_STORE_INVALID;
> +    if (end == start)
> +        return BACKING_STORE_OK;
> +    *end = '\0';
> +    *res = strdup(start);
> +    if (*res == NULL) {
> +        virReportOOMError(conn);
> +        return BACKING_STORE_ERROR;
> +    }
> +    return BACKING_STORE_OK;
> +}
> +
> +/**
> + * Return an absolute path corresponding to PATH, which is absolute or relative
> + * to the directory containing BASE_FILE, or NULL on error
> + */
> +static char *
> +absolutePathFromBaseFile(const char *base_file, const char *path)
> +{
> +    size_t base_size, path_size;
> +    char *res, *p;
> +
> +    if (*path == '/')
> +        return strdup(path);
> +
> +    base_size = strlen(base_file) + 1;
> +    path_size = strlen(path) + 1;
> +    if (VIR_ALLOC_N(res, base_size - 1 + path_size) < 0)
> +        return NULL;
> +    memcpy(res, base_file, base_size);
> +    p = strrchr(res, '/');
> +    if (p != NULL)
> +        p++;
> +    else
> +        p = res;
> +    memcpy(p, path, path_size);
> +    if (VIR_REALLOC_N(res, (p + path_size) - res) < 0) {
> +        /* Ignore failure */
> +    }
> +    return res;
> +}
> +
> +/**
> + * Probe the header of a file to determine what type of disk image
> + * it is, and info about its capacity if available.
> + */
> +int
> +virStorageFileGetMetadataFromFD(virConnectPtr conn,
> +                                const char *path,
> +                                int fd,
> +                                virStorageFileMetadata *meta)
> +{
> +    unsigned char head[20*512]; /* vmdk4GetBackingStore needs this much. */
> +    int len, i;
> +
> +    /* If all else fails, call it a raw file */
> +    meta->format = VIR_STORAGE_FILE_RAW;
> +
> +    if ((len = read(fd, head, sizeof(head))) < 0) {
> +        virReportSystemError(conn, errno, _("cannot read header '%s'"), path);
> +        return -1;
> +    }
> +
> +    /* First check file magic */
> +    for (i = 0 ; i < ARRAY_CARDINALITY(fileTypeInfo) ; i++) {
> +        int mlen;
> +
> +        if (fileTypeInfo[i].magic == NULL)
> +            continue;
> +
> +        /* Validate magic data */
> +        mlen = strlen(fileTypeInfo[i].magic);
> +        if (mlen > len)
> +            continue;
> +        if (memcmp(head, fileTypeInfo[i].magic, mlen) != 0)
> +            continue;
> +
> +        /* Validate version number info */
> +        if (fileTypeInfo[i].versionNumber != -1) {
> +            int version;
> +
> +            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
> +                version = (head[fileTypeInfo[i].versionOffset+3] << 24) |
> +                    (head[fileTypeInfo[i].versionOffset+2] << 16) |
> +                    (head[fileTypeInfo[i].versionOffset+1] << 8) |
> +                    head[fileTypeInfo[i].versionOffset];
> +            } else {
> +                version = (head[fileTypeInfo[i].versionOffset] << 24) |
> +                    (head[fileTypeInfo[i].versionOffset+1] << 16) |
> +                    (head[fileTypeInfo[i].versionOffset+2] << 8) |
> +                    head[fileTypeInfo[i].versionOffset+3];
> +            }
> +            if (version != fileTypeInfo[i].versionNumber)
> +                continue;
> +        }
> +
> +        /* Optionally extract capacity from file */
> +        if (fileTypeInfo[i].sizeOffset != -1) {
> +            if (fileTypeInfo[i].endian == LV_LITTLE_ENDIAN) {
> +                meta->capacity =
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+7] << 56) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+6] << 48) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+5] << 40) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+4] << 32) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+3] << 24) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+2] << 16) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+1] << 8) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset]);
> +            } else {
> +                meta->capacity =
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset] << 56) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+1] << 48) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+2] << 40) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+3] << 32) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+4] << 24) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+5] << 16) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+6] << 8) |
> +                    ((unsigned long long)head[fileTypeInfo[i].sizeOffset+7]);
> +            }
> +            /* Avoid unlikely, but theoretically possible overflow */
> +            if (meta->capacity > (ULLONG_MAX / fileTypeInfo[i].sizeMultiplier))
> +                continue;
> +            meta->capacity *= fileTypeInfo[i].sizeMultiplier;
> +        }
> +
> +        if (fileTypeInfo[i].qcowCryptOffset != -1) {
> +            int crypt_format;
> +
> +            crypt_format = (head[fileTypeInfo[i].qcowCryptOffset] << 24) |
> +                (head[fileTypeInfo[i].qcowCryptOffset+1] << 16) |
> +                (head[fileTypeInfo[i].qcowCryptOffset+2] << 8) |
> +                head[fileTypeInfo[i].qcowCryptOffset+3];
> +            meta->encrypted = crypt_format != 0;
> +        }
> +
> +        /* Validation passed, we know the file format now */
> +        meta->format = fileTypeInfo[i].type;
> +        if (fileTypeInfo[i].getBackingStore != NULL) {
> +            char *base;
> +
> +            switch (fileTypeInfo[i].getBackingStore(conn, &base, head, len)) {
> +            case BACKING_STORE_OK:
> +                break;
> +
> +            case BACKING_STORE_INVALID:
> +                continue;
> +
> +            case BACKING_STORE_ERROR:
> +                return -1;
> +            }
> +            if (base != NULL) {
> +                meta->backingStore = absolutePathFromBaseFile(path, base);
> +                VIR_FREE(base);
> +                if (meta->backingStore == NULL) {
> +                    virReportOOMError(conn);
> +                    return -1;
> +                }
> +            }
> +        }
> +        return 0;
> +    }
> +
> +    /* No magic, so check file extension */
> +    for (i = 0 ; i < ARRAY_CARDINALITY(fileTypeInfo) ; i++) {
> +        if (fileTypeInfo[i].extension == NULL)
> +            continue;
> +
> +        if (!virFileHasSuffix(path, fileTypeInfo[i].extension))
> +            continue;
> +
> +        meta->format = fileTypeInfo[i].type;
> +        return 0;
> +    }
> +
> +    return 0;
> +}
> diff --git a/src/util/storage_file.h b/src/util/storage_file.h
> index b458c0e..e34d749 100644
> --- a/src/util/storage_file.h
> +++ b/src/util/storage_file.h
> @@ -51,4 +51,9 @@ typedef struct _virStorageFileMetadata {
>      bool encrypted;
>  } virStorageFileMetadata;
>  
> +int virStorageFileGetMetadataFromFD(virConnectPtr conn,
> +                                    const char *path,
> +                                    int fd,
> +                                    virStorageFileMetadata *meta);
> +
>  #endif /* __VIR_STORAGE_FILE_H__ */

ACK

Daniel
-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]