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catar/decoder.rs: impl restore dirs, files, and symlinks

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This commit is contained in:
Dietmar Maurer
2019-01-08 17:17:55 +01:00
parent 1ed86a0bae
commit 9b1bb5a277
1 changed files with 127 additions and 36 deletions
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163
src/catar/decoder.rs
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@ -8,12 +8,20 @@ use endian_trait::Endian;
use super::format_definition::*;
use crate::tools;
use std::io::{Read, Seek, SeekFrom};
use std::io::{Read, Write, Seek, SeekFrom};
use std::path::{Path, PathBuf};
use std::os::unix::io::AsRawFd;
use std::os::unix::io::RawFd;
use std::os::unix::io::FromRawFd;
use std::os::unix::ffi::{OsStrExt, OsStringExt};
use std::ffi::{OsStr, OsString};
use nix::fcntl::OFlag;
use nix::sys::stat::Mode;
use nix::errno::Errno;
use nix::NixPath;
pub struct CaDirectoryEntry {
start: u64,
end: u64,
@ -112,6 +120,8 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
bail!("filename entry not nul terminated.");
}
// fixme: check filename is relative (not starting with /)
Ok(std::ffi::OsString::from_vec(buffer))
}
@ -125,19 +135,33 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
self.reader.seek(SeekFrom::Start(start))?;
let mut path = PathBuf::from(".");
let base = ".";
self.restore_sequential(&mut path, &callback)?;
let mut path = PathBuf::from(base);
let dir = match nix::dir::Dir::open(&path, nix::fcntl::OFlag::O_DIRECTORY, nix::sys::stat::Mode::empty()) {
Ok(dir) => dir,
Err(err) => bail!("unable to open base directory - {}", err),
};
let restore_dir = "restoretest";
path.push(restore_dir);
self.restore_sequential(&mut path, &OsString::from(restore_dir), &dir, &callback)?;
Ok(())
}
pub fn restore_sequential<F: Fn(&Path) -> Result<(), Error>>(
&mut self,
path: &mut PathBuf,
path: &mut PathBuf, // user for error reporting
filename: &OsStr, // repeats path last component
parent: &nix::dir::Dir,
callback: &F,
) -> Result<(), Error> {
let parent_fd = parent.as_raw_fd();
// read ENTRY first
let head: CaFormatHeader = self.read_item()?;
check_ca_header::<CaFormatEntry>(&head, CA_FORMAT_ENTRY)?;
@ -145,11 +169,40 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
let mode = entry.mode as u32; //fixme: upper 32bits?
let is_dir = (mode & libc::S_IFMT) == libc::S_IFDIR;
if (mode & libc::S_IFMT) == libc::S_IFDIR {
let dir = match dir_mkdirat(parent_fd, filename) {
Ok(dir) => dir,
Err(err) => bail!("unable to open directory {:?} - {}", path, err),
};
let mut read_buffer: [u8; 64*1024] = unsafe { std::mem::uninitialized() };
//fixme: restore permission, acls, xattr, ...
loop {
loop {
let head: CaFormatHeader = self.read_item()?;
match head.htype {
CA_FORMAT_FILENAME => {
let name = self.read_filename(head.size)?;
path.push(&name);
println!("NAME: {:?}", path);
self.restore_sequential(path, &name, &dir, callback)?;
path.pop();
}
CA_FORMAT_GOODBYE => {
println!("Skip Goodbye");
if head.size < HEADER_SIZE { bail!("detected short goodbye table"); }
self.reader.seek(SeekFrom::Current((head.size - HEADER_SIZE) as i64))?;
return Ok(());
}
_ => {
bail!("got unknown header type inside directory entry {:016x}", head.htype);
}
}
}
}
if (mode & libc::S_IFMT) == libc::S_IFLNK {
// fixme: create symlink
//fixme: restore permission, acls, xattr, ...
let head: CaFormatHeader = self.read_item()?;
match head.htype {
CA_FORMAT_SYMLINK => {
@ -158,24 +211,35 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
}
let target = self.read_symlink(head.size)?;
println!("TARGET: {:?}", target);
return Ok(());
}
CA_FORMAT_FILENAME => {
if !is_dir {
bail!("onyl directoriy entries may contain file names.");
if let Err(err) = symlinkat(&target, parent_fd, filename) {
bail!("create symlink {:?} failed - {}", path, err);
}
let name = self.read_filename(head.size)?;
path.push(name);
println!("NAME: {:?}", path);
self.restore_sequential(path, callback)?;
path.pop();
}
_ => {
bail!("got unknown header type inside symlink entry {:016x}", head.htype);
}
}
return Ok(());
}
if (mode & libc::S_IFMT) == libc::S_IFREG {
let mut read_buffer: [u8; 64*1024] = unsafe { std::mem::uninitialized() };
let flags = OFlag::O_CREAT|OFlag::O_WRONLY|OFlag::O_EXCL;
let open_mode = Mode::from_bits_truncate(0o0600 | mode);
let mut file = match file_openat(parent_fd, filename, flags, open_mode) {
Ok(file) => file,
Err(err) => bail!("open file {:?} failed - {}", path, err),
};
//fixme: restore permission, acls, xattr, ...
let head: CaFormatHeader = self.read_item()?;
match head.htype {
CA_FORMAT_PAYLOAD => {
if ((mode & libc::S_IFMT) != libc::S_IFREG) {
bail!("detected enexpected paylod item.");
}
println!("Skip Payload");
if head.size < HEADER_SIZE {
if head.size < HEADER_SIZE {
bail!("detected short payload");
}
let need = (head.size - HEADER_SIZE) as usize;
@ -187,26 +251,18 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
while (done < need) {
let todo = need - done;
let n = if todo > read_buffer.len() { read_buffer.len() } else { todo };
self.reader.read_exact(&mut read_buffer[..n])?;
// fixme: restore read_buffer[..n]
let data = &mut read_buffer[..n];
self.reader.read_exact(data)?;
file.write_all(data)?;
done += n;
}
return Ok(());
}
CA_FORMAT_GOODBYE => {
if !is_dir {
bail!("onyl directoriy entries may contain goodbye tables.");
}
println!("Skip Goodbye");
if head.size < HEADER_SIZE { bail!("detected short goodbye table"); }
self.reader.seek(SeekFrom::Current((head.size - HEADER_SIZE) as i64))?;
return Ok(());
}
_ => {
bail!("got unknown header type {:016x}", head.htype);
bail!("got unknown header type for file entry {:016x}", head.htype);
}
}
return Ok(());
}
Ok(())
@ -370,3 +426,38 @@ impl <'a, R: Read + Seek> CaTarDecoder<'a, R> {
Ok(())
}
}
fn file_openat(parent: RawFd, filename: &OsStr, flags: OFlag, mode: Mode) -> Result<std::fs::File, Error> {
let fd = filename.with_nix_path(|cstr| unsafe {
nix::fcntl::openat(parent, cstr.as_ref(), flags, mode)
})??;
let file = unsafe { std::fs::File::from_raw_fd(fd) };
Ok(file)
}
fn dir_mkdirat(parent: RawFd, filename: &OsStr) -> Result<nix::dir::Dir, Error> {
// call mkdirat first
let res = filename.with_nix_path(|cstr| unsafe {
libc::mkdirat(parent, cstr.as_ptr(), libc::S_IRWXU)
})?;
Errno::result(res)?;
let dir = nix::dir::Dir::openat(parent, filename, OFlag::O_DIRECTORY, Mode::empty())?;
Ok(dir)
}
fn symlinkat(target: &Path, parent: RawFd, linkname: &OsStr) -> Result<(), Error> {
target.with_nix_path(|target| {
linkname.with_nix_path(|linkname| {
let res = unsafe { libc::symlinkat(target.as_ptr(), parent, linkname.as_ptr()) };
Errno::result(res)?;
Ok(())
})?
})?
}