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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
mod error;
mod file_tree;
#[cfg(test)]
mod tests;
pub use error::DockerArchiveError;
pub use file_tree::FileTree;
use flate2::read::GzDecoder;
use path_clean::clean;
use serde::{Deserialize, Serialize};
use std::cell::RefCell;
use std::collections::HashMap;
use std::fs::OpenOptions;
use std::io::{BufReader, Read};
use std::path::{Path, PathBuf};
use std::process::{Command, Stdio};
use std::rc::Rc;
use tar::{Archive, EntryType};
use which::which;
pub type Result<T> = std::result::Result<T, DockerArchiveError>;
#[derive(Default, Debug, Serialize)]
pub struct ImageArchive {
pub manifest: Manifest,
pub config: Config,
pub layer_map: HashMap<String, Rc<RefCell<FileTree>>>,
}
#[derive(Default, Debug, Deserialize, Serialize)]
pub struct Manifest {
#[serde(rename = "Config")]
pub config_path: String,
#[serde(rename = "RepoTags")]
pub repo_tags: Option<Vec<String>>,
#[serde(rename = "Layers")]
pub layer_tar_paths: Vec<String>,
}
#[derive(Default, Debug, Deserialize, Serialize)]
pub struct Config {
pub history: Vec<HistoryEntry>,
pub rootfs: RootFS,
}
#[derive(Default, Debug, Deserialize, Serialize)]
pub struct RootFS {
#[serde(rename = "type")]
pub typ: String,
pub diff_ids: Vec<String>,
}
#[derive(Default, Debug, Deserialize, Serialize)]
pub struct HistoryEntry {
#[serde(default)]
pub id: String,
#[serde(default)]
pub size: u64,
pub created: String,
#[serde(default)]
pub author: String,
pub created_by: String,
#[serde(default)]
pub empty_layer: bool,
}
impl ImageArchive {
pub fn new_from_url(img_url: &str) -> Result<Self> {
let executable = which("docker").map_or_else(|_| which("podman"), |i| Ok(i))?;
let mut child = Command::new(executable)
.arg("image")
.arg("save")
.arg(img_url)
.stdout(Stdio::piped())
.spawn()?;
let stdout = child
.stdout
.as_mut()
.ok_or(DockerArchiveError::StdoutError)?;
Self::new_from_reader(BufReader::new(stdout))
}
pub fn new_from_file<P: AsRef<Path>>(tar_file: P) -> Result<Self> {
let file = OpenOptions::new().read(true).open(tar_file)?;
Self::new_from_reader(BufReader::new(file))
}
pub fn new_from_reader<R: Read>(obj: R) -> Result<Self> {
let mut img = Self::default();
let mut ar = Archive::new(obj);
let mut json_files: HashMap<String, Vec<u8>> = HashMap::new();
let mut layer_tar_links: HashMap<String, String> = HashMap::new();
for entry in ar.entries()? {
let mut e = entry?;
match e.header().entry_type() {
EntryType::Symlink | EntryType::Regular => {
if let Some(name) = e.path()?.to_str().map(|s| s.to_string()) {
if name.ends_with(".tar") {
if e.header().entry_type().eq(&EntryType::Symlink) {
if let Ok(Some(p)) = e.header().link_name() {
let tmp = PathBuf::from(&name);
if let Some(tmp_parent) = tmp.parent() {
layer_tar_links.insert(
name,
clean(&tmp_parent.join(p).to_string_lossy()),
);
} else {
layer_tar_links.insert(name, clean(&p.to_string_lossy()));
}
}
} else {
let layer_tree = FileTree::build_from_layer_tar(Archive::new(e))?;
layer_tree.borrow_mut().name = name.clone();
img.layer_map.insert(name, layer_tree);
}
} else if name.ends_with(".tar.gz") || name.ends_with("tgz") {
if e.header().entry_type().eq(&EntryType::Symlink) {
if let Ok(Some(p)) = e.header().link_name() {
let tmp = PathBuf::from(&name);
if let Some(tmp_parent) = tmp.parent() {
layer_tar_links.insert(
name,
clean(&tmp_parent.join(p).to_string_lossy()),
);
} else {
layer_tar_links.insert(name, clean(&p.to_string_lossy()));
}
}
} else {
let layer_tree = FileTree::build_from_layer_tar(Archive::new(
GzDecoder::new(e),
))?;
layer_tree.borrow_mut().name = name.clone();
img.layer_map.insert(name, layer_tree);
}
} else if name.ends_with(".json") || name.starts_with("sha256:") {
let mut content = vec![];
e.read_to_end(&mut content)?;
json_files.insert(name, content);
}
}
}
_ => (),
}
}
for (k, v) in layer_tar_links.iter() {
if let Some(tree) = img.layer_map.get(v).map(Rc::clone) {
img.layer_map.insert(k.clone(), tree);
}
}
if let Some(data) = json_files.get("manifest.json") {
let manifests: Vec<Manifest> = serde_json::from_slice(data)?;
img.manifest =
manifests
.into_iter()
.nth(0)
.ok_or(DockerArchiveError::InvalidArchive(
"image manifest is empty",
))?;
} else {
return Err(DockerArchiveError::InvalidArchive(
"could not find image manifest",
));
}
if let Some(data) = json_files.get(&img.manifest.config_path) {
let mut config: Config = serde_json::from_slice(data)?;
let mut layer_idx = 0;
for h in config.history.iter_mut() {
if h.empty_layer {
h.id = "<missing>".to_string();
} else if let Some(s) = config.rootfs.diff_ids.get(layer_idx) {
h.id = s.clone();
layer_idx += 1;
}
}
img.config = config;
} else {
return Err(DockerArchiveError::InvalidArchive(
"could not find image config",
));
}
Ok(img)
}
pub fn merged_tree(&self) -> Rc<RefCell<FileTree>> {
FileTree::stack_trees(
self.manifest
.layer_tar_paths
.iter()
.map(|path| self.layer_map.get(path))
.filter(|i| i.is_some())
.map(|i| Rc::clone(i.unwrap()))
.collect(),
)
}
}
