binstall_tar/
pax.rs

1#![allow(dead_code)]
2use std::io;
3use std::slice;
4use std::str;
5
6use crate::other;
7
8// Keywords for PAX extended header records.
9pub const PAX_NONE: &str = ""; // Indicates that no PAX key is suitable
10pub const PAX_PATH: &str = "path";
11pub const PAX_LINKPATH: &str = "linkpath";
12pub const PAX_SIZE: &str = "size";
13pub const PAX_UID: &str = "uid";
14pub const PAX_GID: &str = "gid";
15pub const PAX_UNAME: &str = "uname";
16pub const PAX_GNAME: &str = "gname";
17pub const PAX_MTIME: &str = "mtime";
18pub const PAX_ATIME: &str = "atime";
19pub const PAX_CTIME: &str = "ctime"; // Removed from later revision of PAX spec, but was valid
20pub const PAX_CHARSET: &str = "charset"; // Currently unused
21pub const PAX_COMMENT: &str = "comment"; // Currently unused
22
23pub const PAX_SCHILYXATTR: &str = "SCHILY.xattr.";
24
25// Keywords for GNU sparse files in a PAX extended header.
26pub const PAX_GNUSPARSE: &str = "GNU.sparse.";
27pub const PAX_GNUSPARSENUMBLOCKS: &str = "GNU.sparse.numblocks";
28pub const PAX_GNUSPARSEOFFSET: &str = "GNU.sparse.offset";
29pub const PAX_GNUSPARSENUMBYTES: &str = "GNU.sparse.numbytes";
30pub const PAX_GNUSPARSEMAP: &str = "GNU.sparse.map";
31pub const PAX_GNUSPARSENAME: &str = "GNU.sparse.name";
32pub const PAX_GNUSPARSEMAJOR: &str = "GNU.sparse.major";
33pub const PAX_GNUSPARSEMINOR: &str = "GNU.sparse.minor";
34pub const PAX_GNUSPARSESIZE: &str = "GNU.sparse.size";
35pub const PAX_GNUSPARSEREALSIZE: &str = "GNU.sparse.realsize";
36
37/// An iterator over the pax extensions in an archive entry.
38///
39/// This iterator yields structures which can themselves be parsed into
40/// key/value pairs.
41pub struct PaxExtensions<'entry> {
42    data: slice::Split<'entry, u8, fn(&u8) -> bool>,
43}
44
45impl<'entry> PaxExtensions<'entry> {
46    /// Create new pax extensions iterator from the given entry data.
47    pub fn new(a: &'entry [u8]) -> Self {
48        fn is_newline(a: &u8) -> bool {
49            *a == b'\n'
50        }
51        PaxExtensions {
52            data: a.split(is_newline),
53        }
54    }
55}
56
57/// A key/value pair corresponding to a pax extension.
58pub struct PaxExtension<'entry> {
59    key: &'entry [u8],
60    value: &'entry [u8],
61}
62
63pub fn pax_extensions_value(a: &[u8], key: &str) -> Option<u64> {
64    for extension in PaxExtensions::new(a) {
65        let current_extension = match extension {
66            Ok(ext) => ext,
67            Err(_) => return None,
68        };
69        if current_extension.key() != Ok(key) {
70            continue;
71        }
72
73        let value = match current_extension.value() {
74            Ok(value) => value,
75            Err(_) => return None,
76        };
77        let result = match value.parse::<u64>() {
78            Ok(result) => result,
79            Err(_) => return None,
80        };
81        return Some(result);
82    }
83    None
84}
85
86impl<'entry> Iterator for PaxExtensions<'entry> {
87    type Item = io::Result<PaxExtension<'entry>>;
88
89    fn next(&mut self) -> Option<io::Result<PaxExtension<'entry>>> {
90        let line = match self.data.next() {
91            Some(line) if line.is_empty() => return None,
92            Some(line) => line,
93            None => return None,
94        };
95
96        Some(
97            line.iter()
98                .position(|b| *b == b' ')
99                .and_then(|i| {
100                    str::from_utf8(&line[..i])
101                        .ok()
102                        .and_then(|len| len.parse::<usize>().ok().map(|j| (i + 1, j)))
103                })
104                .and_then(|(kvstart, reported_len)| {
105                    if line.len() + 1 == reported_len {
106                        line[kvstart..]
107                            .iter()
108                            .position(|b| *b == b'=')
109                            .map(|equals| (kvstart, equals))
110                    } else {
111                        None
112                    }
113                })
114                .map(|(kvstart, equals)| PaxExtension {
115                    key: &line[kvstart..kvstart + equals],
116                    value: &line[kvstart + equals + 1..],
117                })
118                .ok_or_else(|| other("malformed pax extension")),
119        )
120    }
121}
122
123impl<'entry> PaxExtension<'entry> {
124    /// Returns the key for this key/value pair parsed as a string.
125    ///
126    /// May fail if the key isn't actually utf-8.
127    pub fn key(&self) -> Result<&'entry str, str::Utf8Error> {
128        str::from_utf8(self.key)
129    }
130
131    /// Returns the underlying raw bytes for the key of this key/value pair.
132    pub fn key_bytes(&self) -> &'entry [u8] {
133        self.key
134    }
135
136    /// Returns the value for this key/value pair parsed as a string.
137    ///
138    /// May fail if the value isn't actually utf-8.
139    pub fn value(&self) -> Result<&'entry str, str::Utf8Error> {
140        str::from_utf8(self.value)
141    }
142
143    /// Returns the underlying raw bytes for this value of this key/value pair.
144    pub fn value_bytes(&self) -> &'entry [u8] {
145        self.value
146    }
147}
binstall_tar/pax.rs

binstall_tar/
pax.rs
