Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func SourceSize ¶
SourceSize sizes an opened capture source; Seek(END) covers regular files and Unix block devices alike. See sourcesize_windows.go for why this is the ONE shared derivation (#309).
func VolumeSize ¶
VolumeSize is a no-op on non-Windows platforms.
Types ¶
type Disk ¶ added in v0.2.8
type Disk struct {
Path string `json:"path"`
Bytes int64 `json:"bytes"`
// Serial and Removable as the OS reports them: the storage descriptor
// on Windows (a USB, SD or MMC bus counts as removable whatever the
// media bit says), sysfs on Linux (the removable flag, or a device
// path through a USB controller), diskutil on macOS.
Serial string `json:"serial,omitempty"`
Removable bool `json:"removable"`
}
Disk is a physical disk in capture form: \\.\PhysicalDriveN on Windows, /dev/sdX or /dev/nvme0n1 on Linux, /dev/diskN on macOS.
type Enumerator ¶ added in v0.2.8
type Enumerator struct {
// Linux: the mount table (/proc/self/mounts), the mountinfo table
// (/proc/self/mountinfo), the sysfs block tree (/sys/block) and the
// directory device nodes live in (/dev). Empty = the real ones.
Mounts, Mountinfo, SysBlock, DevRoot string
// Diskutil runs macOS's diskutil with args; nil = exec it.
Diskutil func(args ...string) ([]byte, error)
}
Enumerator reads the machine. The zero value reads the real OS; the fields are the seams tests feed fixtures through.
func DefaultEnumerator ¶ added in v0.2.8
func DefaultEnumerator() Enumerator
DefaultEnumerator honors the fixture environment the product's tests use: DISKNEXUS_SYS_BLOCK, DISKNEXUS_PROC_MOUNTS, DISKNEXUS_DEV_ROOT.
func (Enumerator) Disks ¶ added in v0.2.8
func (e Enumerator) Disks() ([]Disk, error)
Disks lists the physical disks a capture can name. Loop, RAM and zram devices are not disks.
func (Enumerator) SystemDisk ¶ added in v0.2.8
func (e Enumerator) SystemDisk() (string, error)
SystemDisk is the disk the running OS boots from, in Disk.Path form; an error when it cannot be resolved.
func (Enumerator) Volumes ¶ added in v0.2.8
func (e Enumerator) Volumes() ([]VolumeInfo, error)
Volumes lists the filesystems the OS knows, mounted or not where the OS can say. A volume the OS lists but cannot describe is still returned; the caller decides what an unreadable one means.
type ExcludedReader ¶
type ExcludedReader struct {
// contains filtered or unexported fields
}
ExcludedReader wraps a reader and zeros out excluded regions.
func NewExcludedReader ¶
func NewExcludedReader(r io.Reader, exclusions *ExclusionMap) *ExcludedReader
NewExcludedReader wraps a reader with an exclusion map.
func NewExcludedReaderAt ¶
func NewExcludedReaderAt(r io.Reader, exclusions *ExclusionMap, startOffset int64) *ExcludedReader
NewExcludedReaderAt wraps a reader whose next byte is at startOffset on the source volume. Used to resume a volatile-exclusion backup (#54): the inner reader has been seeked to the resume offset, so the exclusion bookkeeping must start there rather than at 0.
type ExclusionMap ¶
type ExclusionMap struct {
// contains filtered or unexported fields
}
ExclusionMap marks byte ranges to skip (write as zeros). Used for volatile files like pagefile.sys.
func NewExclusionMap ¶
func NewExclusionMap() *ExclusionMap
NewExclusionMap creates an empty exclusion map.
func (*ExclusionMap) AddRange ¶
func (m *ExclusionMap) AddRange(start, length int64)
AddRange marks a byte range as excluded.
func (*ExclusionMap) CoveredBytes ¶
func (m *ExclusionMap) CoveredBytes() int64
CoveredBytes is the number of distinct bytes the map excludes — overlaps between passes (volatile, subtree, live-extent) counted once. It is what an operator-facing "excluding X (N MB)" line reports (#468).
func (*ExclusionMap) IsExcluded ¶
func (m *ExclusionMap) IsExcluded(offset, length int64) bool
IsExcluded returns true if any byte in the range [offset, offset+length) is excluded. Binary search over the sorted ranges: catalog marking (#94) calls this once per extent across whole-volume catalogs, where a linear scan of a large repo-subtree map would be O(files × ranges).
func (*ExclusionMap) Len ¶
func (m *ExclusionMap) Len() int
Len returns the number of excluded ranges.
func (*ExclusionMap) ZeroExcluded ¶
func (m *ExclusionMap) ZeroExcluded(p []byte, bufStart int64)
ZeroExcluded zeros the bytes of p that fall in an excluded range, where p represents the source bytes starting at bufStart. This is the same masking ExcludedReader applies to the stream, exposed so the resume boundary probe can reproduce the exact bytes the pipeline hashed (#54).
type Reader ¶
type Reader struct {
// contains filtered or unexported fields
}
Reader provides sequential reading of a volume or file for the backup pipeline.
func NewReader ¶
NewReader opens a volume device path or file for reading. bufferSize controls the read chunk size (default 1 MB).
func (*Reader) SeekTo ¶
SeekTo repositions the reader so the next Read returns the byte at off. It is used to resume an interrupted backup from a checkpoint offset (#42). For a buffered file it is a plain seek. For a direct-I/O device it seeks to the sector floor (O_DIRECT requires sector-aligned reads) and discards the sub-sector remainder, so the next Read still delivers byte off exactly.
type VolumeInfo ¶ added in v0.2.8
type VolumeInfo struct {
Device string `json:"device"`
MountPoint string `json:"mount_point,omitempty"` // "" when unmounted
Filesystem string `json:"filesystem,omitempty"`
Label string `json:"label,omitempty"`
Bytes int64 `json:"bytes"`
Disk string `json:"disk,omitempty"` // the whole disk, in Disk.Path form
DiskSerial string `json:"disk_serial,omitempty"`
Removable bool `json:"removable"`
}
VolumeInfo is a filesystem the OS knows about, with the disk it sits on. Device is the raw node a capture opens; Filesystem and Label are what the OS reported (empty when it reported nothing; the boot sector is the authority and the caller reads it through volumefs.IdentityAuto).
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
Writer provides random-access writing to a file or device for restoring backups.
func NewWriter ¶
NewWriter opens or creates a file for writing at arbitrary offsets. For device paths (e.g., \\.\PhysicalDrive0), platform-specific opening is used.
Source Files