-
Notifications
You must be signed in to change notification settings - Fork 0
/
cpio.go
166 lines (150 loc) · 3.61 KB
/
cpio.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
// Copyright 2013-2017 the u-root Authors. All rights reserved
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package cpio implements utilities for reading and writing cpio archives.
//
// Currently, only newc-formatted cpio archives are supported through cpio.Newc.
//
// Reading from or writing to a file:
//
// f, err := os.Open(...)
// if err ...
// recReader := cpio.Newc.Reader(f)
// err := ForEachRecord(recReader, func(r cpio.Record) error {
//
// })
//
// // Or...
// recWriter := cpio.Newc.Writer(f)
//
//
// Reading from or writing to an in-memory archive:
//
// a := cpio.InMemArchive()
// err := a.WriteRecord(...)
//
// recReader := a.Reader() // Reads from the "beginning."
//
// if a.Contains("bar/foo") {
//
// }
package cpio
import (
"fmt"
"io"
"os"
"time"
"github.com/u-root/u-root/pkg/ls"
)
var (
formatMap = make(map[string]RecordFormat)
// Debug can be set e.g. to log.Printf to enable debug prints from
// marshaling/unmarshaling cpio archives.
Debug = func(string, ...interface{}) {}
)
// Record represents a CPIO record, which represents a Unix file.
type Record struct {
// ReaderAt contains the content of this CPIO record.
io.ReaderAt
// Info is metadata describing the CPIO record.
Info
// metadata about this item's place in the file
RecPos int64 // Where in the file this record is
RecLen uint64 // How big the record is.
FilePos int64 // Where in the CPIO the file's contents are.
}
// String implements a fmt.Stringer for Record.
//
// String returns a string long-formatted like `ls` would format it.
func (r Record) String() string {
s := ls.LongStringer{
Human: true,
Name: ls.NameStringer{},
}
return s.FileString(LSInfoFromRecord(r))
}
// Info holds metadata about files.
type Info struct {
Ino uint64
Mode uint64
UID uint64
GID uint64
NLink uint64
MTime uint64
FileSize uint64
Dev uint64
Major uint64
Minor uint64
Rmajor uint64
Rminor uint64
Name string
}
func (i Info) String() string {
return fmt.Sprintf("%s: Ino %d Mode %#o UID %d GID %d NLink %d MTime %v FileSize %d Major %d Minor %d Rmajor %d Rminor %d",
i.Name,
i.Ino,
i.Mode,
i.UID,
i.GID,
i.NLink,
time.Unix(int64(i.MTime), 0).UTC(),
i.FileSize,
i.Major,
i.Minor,
i.Rmajor,
i.Rminor)
}
// A RecordReader reads one record from an archive.
type RecordReader interface {
ReadRecord() (Record, error)
}
// A RecordWriter writes one record to an archive.
type RecordWriter interface {
WriteRecord(Record) error
}
// A RecordFormat gives readers and writers for dealing with archives from io
// objects.
//
// CPIO files have a number of records, of which newc is the most widely used
// today.
type RecordFormat interface {
Reader(r io.ReaderAt) RecordReader
Writer(w io.Writer) RecordWriter
}
// Format returns the RecordFormat with that name, if it exists.
func Format(name string) (RecordFormat, error) {
op, ok := formatMap[name]
if !ok {
return nil, fmt.Errorf("%q is not in cpio format map %v", name, formatMap)
}
return op, nil
}
func modeFromLinux(mode uint64) os.FileMode {
m := os.FileMode(mode & 0777)
switch mode & S_IFMT {
case S_IFBLK:
m |= os.ModeDevice
case S_IFCHR:
m |= os.ModeDevice | os.ModeCharDevice
case S_IFDIR:
m |= os.ModeDir
case S_IFIFO:
m |= os.ModeNamedPipe
case S_IFLNK:
m |= os.ModeSymlink
case S_IFREG:
// nothing to do
case S_IFSOCK:
m |= os.ModeSocket
}
if mode&S_ISGID != 0 {
m |= os.ModeSetgid
}
if mode&S_ISUID != 0 {
m |= os.ModeSetuid
}
if mode&S_ISVTX != 0 {
m |= os.ModeSticky
}
return m
}