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|
pub const Options = struct {
/// Number of directory levels to skip when extracting files.
strip_components: u32 = 0,
/// How to handle the "mode" property of files from within the tar file.
mode_mode: ModeMode = .executable_bit_only,
const ModeMode = enum {
/// The mode from the tar file is completely ignored. Files are created
/// with the default mode when creating files.
ignore,
/// The mode from the tar file is inspected for the owner executable bit
/// only. This bit is copied to the group and other executable bits.
/// Other bits of the mode are left as the default when creating files.
executable_bit_only,
};
};
pub const Header = struct {
bytes: *const [512]u8,
pub const FileType = enum(u8) {
normal = '0',
hard_link = '1',
symbolic_link = '2',
character_special = '3',
block_special = '4',
directory = '5',
fifo = '6',
contiguous = '7',
global_extended_header = 'g',
extended_header = 'x',
_,
};
pub fn fileSize(header: Header) !u64 {
const raw = header.bytes[124..][0..12];
const ltrimmed = std.mem.trimLeft(u8, raw, "0");
const rtrimmed = std.mem.trimRight(u8, ltrimmed, " \x00");
if (rtrimmed.len == 0) return 0;
return std.fmt.parseInt(u64, rtrimmed, 8);
}
pub fn is_ustar(header: Header) bool {
return std.mem.eql(u8, header.bytes[257..][0..6], "ustar\x00");
}
/// Includes prefix concatenated, if any.
/// Return value may point into Header buffer, or might point into the
/// argument buffer.
/// TODO: check against "../" and other nefarious things
pub fn fullFileName(header: Header, buffer: *[255]u8) ![]const u8 {
const n = name(header);
if (!is_ustar(header))
return n;
const p = prefix(header);
if (p.len == 0)
return n;
@memcpy(buffer[0..p.len], p);
buffer[p.len] = '/';
@memcpy(buffer[p.len + 1 ..][0..n.len], n);
return buffer[0 .. p.len + 1 + n.len];
}
pub fn name(header: Header) []const u8 {
return str(header, 0, 0 + 100);
}
pub fn prefix(header: Header) []const u8 {
return str(header, 345, 345 + 155);
}
pub fn fileType(header: Header) FileType {
const result = @enumFromInt(FileType, header.bytes[156]);
return if (result == @enumFromInt(FileType, 0)) .normal else result;
}
fn str(header: Header, start: usize, end: usize) []const u8 {
var i: usize = start;
while (i < end) : (i += 1) {
if (header.bytes[i] == 0) break;
}
return header.bytes[start..i];
}
};
pub fn pipeToFileSystem(dir: std.fs.Dir, reader: anytype, options: Options) !void {
switch (options.mode_mode) {
.ignore => {},
.executable_bit_only => {
// This code does not look at the mode bits yet. To implement this feature,
// the implementation must be adjusted to look at the mode, and check the
// user executable bit, then call fchmod on newly created files when
// the executable bit is supposed to be set.
// It also needs to properly deal with ACLs on Windows.
@panic("TODO: unimplemented: tar ModeMode.executable_bit_only");
},
}
var file_name_buffer: [255]u8 = undefined;
var buffer: [512 * 8]u8 = undefined;
var start: usize = 0;
var end: usize = 0;
header: while (true) {
if (buffer.len - start < 1024) {
const dest_end = end - start;
@memcpy(buffer[0..dest_end], buffer[start..end]);
end = dest_end;
start = 0;
}
const ask_header = @min(buffer.len - end, 1024 -| (end - start));
end += try reader.readAtLeast(buffer[end..], ask_header);
switch (end - start) {
0 => return,
1...511 => return error.UnexpectedEndOfStream,
else => {},
}
const header: Header = .{ .bytes = buffer[start..][0..512] };
start += 512;
const file_size = try header.fileSize();
const rounded_file_size = std.mem.alignForward(u64, file_size, 512);
const pad_len = @intCast(usize, rounded_file_size - file_size);
const unstripped_file_name = try header.fullFileName(&file_name_buffer);
switch (header.fileType()) {
.directory => {
const file_name = try stripComponents(unstripped_file_name, options.strip_components);
if (file_name.len != 0) {
try dir.makePath(file_name);
}
},
.normal => {
if (file_size == 0 and unstripped_file_name.len == 0) return;
const file_name = try stripComponents(unstripped_file_name, options.strip_components);
if (std.fs.path.dirname(file_name)) |dir_name| {
try dir.makePath(dir_name);
}
var file = try dir.createFile(file_name, .{});
defer file.close();
var file_off: usize = 0;
while (true) {
if (buffer.len - start < 1024) {
const dest_end = end - start;
@memcpy(buffer[0..dest_end], buffer[start..end]);
end = dest_end;
start = 0;
}
// Ask for the rounded up file size + 512 for the next header.
// TODO: https://github.com/ziglang/zig/issues/14039
const ask = @intCast(usize, @min(
buffer.len - end,
rounded_file_size + 512 - file_off -| (end - start),
));
end += try reader.readAtLeast(buffer[end..], ask);
if (end - start < ask) return error.UnexpectedEndOfStream;
// TODO: https://github.com/ziglang/zig/issues/14039
const slice = buffer[start..@intCast(usize, @min(file_size - file_off + start, end))];
try file.writeAll(slice);
file_off += slice.len;
start += slice.len;
if (file_off >= file_size) {
start += pad_len;
// Guaranteed since we use a buffer divisible by 512.
assert(start <= end);
continue :header;
}
}
},
.global_extended_header, .extended_header => {
if (start + rounded_file_size > end) return error.TarHeadersTooBig;
start = @intCast(usize, start + rounded_file_size);
},
.hard_link => return error.TarUnsupportedFileType,
.symbolic_link => return error.TarUnsupportedFileType,
else => return error.TarUnsupportedFileType,
}
}
}
fn stripComponents(path: []const u8, count: u32) ![]const u8 {
var i: usize = 0;
var c = count;
while (c > 0) : (c -= 1) {
if (std.mem.indexOfScalarPos(u8, path, i, '/')) |pos| {
i = pos + 1;
} else {
return error.TarComponentsOutsideStrippedPrefix;
}
}
return path[i..];
}
test stripComponents {
const expectEqualStrings = std.testing.expectEqualStrings;
try expectEqualStrings("a/b/c", try stripComponents("a/b/c", 0));
try expectEqualStrings("b/c", try stripComponents("a/b/c", 1));
try expectEqualStrings("c", try stripComponents("a/b/c", 2));
}
const std = @import("std.zig");
const assert = std.debug.assert;
|
