[libvirt] [PATCH v2 2/6] util: use helper functions for extracting image headers

Rename/retype the little endian functions used for qed images and add corresponding big endian ones. --- src/util/virstoragefile.c | 152 ++++++++++++++++++++-------------------------- 1 file changed, 66 insertions(+), 86 deletions(-) diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c index 6e2d61e..9e50ccb 100644 --- a/src/util/virstoragefile.c +++ b/src/util/virstoragefile.c @@ -208,6 +208,51 @@ static struct FileTypeInfo const fileTypeInfo[] = { }; verify(ARRAY_CARDINALITY(fileTypeInfo) == VIR_STORAGE_FILE_LAST); + +static uint64_t +getBEHeader64(const unsigned char *buf) +{ + return (((uint64_t)buf[0] << 56) + | ((uint64_t)buf[1] << 48) + | ((uint64_t)buf[2] << 40) + | ((uint64_t)buf[3] << 32) + | ((uint64_t)buf[4] << 24) + | ((uint64_t)buf[5] << 16) + | ((uint64_t)buf[6] << 8) + | ((uint64_t)buf[7])); +} + +static uint32_t +getBEHeader32(const unsigned char *buf) +{ + return (((uint32_t)buf[0] << 24) + | ((uint32_t)buf[1] << 16) + | ((uint32_t)buf[2] << 8) + | ((uint32_t)buf[3])); +} + +static uint32_t +getLEHeader32(const unsigned char *loc) +{ + return (((uint32_t)loc[3] << 24) | + ((uint32_t)loc[2] << 16) | + ((uint32_t)loc[1] << 8) | + ((uint32_t)loc[0] << 0)); +} + +static uint64_t +getLEHeader64(const unsigned char *loc) +{ + return (((uint64_t)loc[7] << 56) | + ((uint64_t)loc[6] << 48) | + ((uint64_t)loc[5] << 40) | + ((uint64_t)loc[4] << 32) | + ((uint64_t)loc[3] << 24) | + ((uint64_t)loc[2] << 16) | + ((uint64_t)loc[1] << 8) | + ((uint64_t)loc[0] << 0)); +} + static int cowGetBackingStore(char **res, int *format, @@ -255,16 +300,8 @@ qcow2GetBackingStoreFormat(int *format, */ while (offset < (buf_size-8) && offset < (extension_end-8)) { - unsigned int magic = - (buf[offset] << 24) + - (buf[offset+1] << 16) + - (buf[offset+2] << 8) + - (buf[offset+3]); - unsigned int len = - (buf[offset+4] << 24) + - (buf[offset+5] << 16) + - (buf[offset+6] << 8) + - (buf[offset+7]); + unsigned int magic = getBEHeader32(buf + offset); + unsigned int len = getBEHeader32(buf + offset + 4); offset += 8; @@ -312,20 +349,12 @@ qcowXGetBackingStore(char **res, if (buf_size < QCOWX_HDR_BACKING_FILE_OFFSET+8+4) return BACKING_STORE_INVALID; - offset = (((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET] << 56) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+1] << 48) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+2] << 40) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+3] << 32) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+4] << 24) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+5] << 16) - | ((unsigned long long)buf[QCOWX_HDR_BACKING_FILE_OFFSET+6] << 8) - | buf[QCOWX_HDR_BACKING_FILE_OFFSET+7]); /* QCowHeader.backing_file_offset */ + /* QCowHeader.backing_file_offset */ + offset = getBEHeader64(buf + QCOWX_HDR_BACKING_FILE_OFFSET); if (offset > buf_size) return BACKING_STORE_INVALID; - size = ((buf[QCOWX_HDR_BACKING_FILE_SIZE] << 24) - | (buf[QCOWX_HDR_BACKING_FILE_SIZE+1] << 16) - | (buf[QCOWX_HDR_BACKING_FILE_SIZE+2] << 8) - | buf[QCOWX_HDR_BACKING_FILE_SIZE+3]); /* QCowHeader.backing_file_size */ + /* QCowHeader.backing_file_size */ + size = getBEHeader32(buf + QCOWX_HDR_BACKING_FILE_SIZE); if (size == 0) { if (format) *format = VIR_STORAGE_FILE_NONE; @@ -468,28 +497,6 @@ cleanup: return ret; } -static unsigned long -qedGetHeaderUL(const unsigned char *loc) -{ - return (((unsigned long)loc[3] << 24) | - ((unsigned long)loc[2] << 16) | - ((unsigned long)loc[1] << 8) | - ((unsigned long)loc[0] << 0)); -} - -static unsigned long long -qedGetHeaderULL(const unsigned char *loc) -{ - return (((unsigned long long)loc[7] << 56) | - ((unsigned long long)loc[6] << 48) | - ((unsigned long long)loc[5] << 40) | - ((unsigned long long)loc[4] << 32) | - ((unsigned long long)loc[3] << 24) | - ((unsigned long long)loc[2] << 16) | - ((unsigned long long)loc[1] << 8) | - ((unsigned long long)loc[0] << 0)); -} - static int qedGetBackingStore(char **res, int *format, @@ -503,7 +510,7 @@ qedGetBackingStore(char **res, /* Check if this image has a backing file */ if (buf_size < QED_HDR_FEATURES_OFFSET+8) return BACKING_STORE_INVALID; - flags = qedGetHeaderULL(buf + QED_HDR_FEATURES_OFFSET); + flags = getLEHeader64(buf + QED_HDR_FEATURES_OFFSET); if (!(flags & QED_F_BACKING_FILE)) { *format = VIR_STORAGE_FILE_NONE; return BACKING_STORE_OK; @@ -512,10 +519,10 @@ qedGetBackingStore(char **res, /* Parse the backing file */ if (buf_size < QED_HDR_BACKING_FILE_OFFSET+8) return BACKING_STORE_INVALID; - offset = qedGetHeaderUL(buf + QED_HDR_BACKING_FILE_OFFSET); + offset = getLEHeader32(buf + QED_HDR_BACKING_FILE_OFFSET); if (offset > buf_size) return BACKING_STORE_INVALID; - size = qedGetHeaderUL(buf + QED_HDR_BACKING_FILE_SIZE); + size = getLEHeader32(buf + QED_HDR_BACKING_FILE_SIZE); if (size == 0) return BACKING_STORE_OK; if (offset + size > buf_size || offset + size < offset) @@ -633,19 +640,10 @@ virStorageFileMatchesVersion(int format, if ((fileTypeInfo[format].versionOffset + 4) > buflen) return false; - if (fileTypeInfo[format].endian == LV_LITTLE_ENDIAN) { - version = - (buf[fileTypeInfo[format].versionOffset+3] << 24) | - (buf[fileTypeInfo[format].versionOffset+2] << 16) | - (buf[fileTypeInfo[format].versionOffset+1] << 8) | - (buf[fileTypeInfo[format].versionOffset]); - } else { - version = - (buf[fileTypeInfo[format].versionOffset] << 24) | - (buf[fileTypeInfo[format].versionOffset+1] << 16) | - (buf[fileTypeInfo[format].versionOffset+2] << 8) | - (buf[fileTypeInfo[format].versionOffset+3]); - } + if (fileTypeInfo[format].endian == LV_LITTLE_ENDIAN) + version = getLEHeader32(buf + fileTypeInfo[format].versionOffset); + else + version = getBEHeader32(buf + fileTypeInfo[format].versionOffset); VIR_DEBUG("Compare detected version %d vs expected version %d", version, fileTypeInfo[format].versionNumber); @@ -688,25 +686,11 @@ virStorageFileGetMetadataFromBuf(int format, return 1; if (fileTypeInfo[format].endian == LV_LITTLE_ENDIAN) { - meta->capacity = - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+7] << 56) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+6] << 48) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+5] << 40) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+4] << 32) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+3] << 24) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+2] << 16) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+1] << 8) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset]); + meta->capacity = getLEHeader64(buf + + fileTypeInfo[format].sizeOffset); } else { - meta->capacity = - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset] << 56) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+1] << 48) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+2] << 40) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+3] << 32) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+4] << 24) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+5] << 16) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+6] << 8) | - ((unsigned long long)buf[fileTypeInfo[format].sizeOffset+7]); + meta->capacity = getBEHeader64(buf + + fileTypeInfo[format].sizeOffset); } /* Avoid unlikely, but theoretically possible overflow */ if (meta->capacity > (ULLONG_MAX / fileTypeInfo[format].sizeMultiplier)) @@ -715,14 +699,10 @@ virStorageFileGetMetadataFromBuf(int format, } if (fileTypeInfo[format].qcowCryptOffset != -1) { - int crypt_format; - - crypt_format = - (buf[fileTypeInfo[format].qcowCryptOffset] << 24) | - (buf[fileTypeInfo[format].qcowCryptOffset+1] << 16) | - (buf[fileTypeInfo[format].qcowCryptOffset+2] << 8) | - (buf[fileTypeInfo[format].qcowCryptOffset+3]); - meta->encrypted = crypt_format != 0; + int crypt_fmt; + + crypt_fmt = getBEHeader32(buf + fileTypeInfo[format].qcowCryptOffset); + meta->encrypted = crypt_fmt != 0; } if (fileTypeInfo[format].getBackingStore != NULL) { -- 1.7.12.4