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catar/encoder.rs: encode linux fs attributes, cleanup encoder

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Try to avoid duplicate stat calls (assume file tree is stable during backup).
This commit is contained in:
Dietmar Maurer
2019-01-11 09:20:10 +01:00
parent ddbdf80d51
commit 4f6892eb74
2 changed files with 180 additions and 63 deletions
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182
src/catar/encoder.rs
View File

@ -3,6 +3,7 @@
//! This module contain the code to generate *catar* archive files.
use failure::*;
use endian_trait::Endian;
use super::format_definition::*;
use super::binary_search_tree::*;
@ -52,7 +53,17 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
};
// todo: use scandirat??
me.encode_dir(dir)?;
let stat = match nix::sys::stat::fstat(dir.as_raw_fd()) {
Ok(stat) => stat,
Err(err) => bail!("fstat {:?} failed - {}", me.current_path, err),
};
if (stat.st_mode & libc::S_IFMT) != libc::S_IFDIR {
bail!("got unexpected file type {:?} (not a directory)", me.current_path);
}
me.encode_dir(dir, &stat)?;
Ok(())
}
@ -63,6 +74,22 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
Ok(())
}
fn write_item<T: Endian + Clone>(&mut self, item: &T) -> Result<(), Error> {
let mut data: T = unsafe { std::mem::uninitialized() };
data = (*item).clone().to_le();
let buffer = unsafe { std::slice::from_raw_parts(
&data as *const T as *const u8,
std::mem::size_of::<T>()
)};
self.write(buffer)?;
Ok(())
}
fn flush_copy_buffer(&mut self, size: usize) -> Result<(), Error> {
self.writer.write_all(&self.file_copy_buffer[..size])?;
self.writer_pos += size;
@ -71,12 +98,8 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
fn write_header(&mut self, htype: u64, size: u64) -> Result<(), Error> {
let mut buffer = [0u8; std::mem::size_of::<CaFormatHeader>()];
let mut header = crate::tools::map_struct_mut::<CaFormatHeader>(&mut buffer)?;
header.size = u64::to_le((std::mem::size_of::<CaFormatHeader>() as u64) + size);
header.htype = u64::to_le(htype);
self.write(&buffer)?;
let size = size + (std::mem::size_of::<CaFormatHeader>() as u64);
self.write_item(&CaFormatHeader { size, htype })?;
Ok(())
}
@ -90,33 +113,46 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
Ok(())
}
fn write_entry(&mut self, stat: &FileStat) -> Result<(), Error> {
fn create_entry(&self, stat: &FileStat) -> Result<CaFormatEntry, Error> {
let mut buffer = [0u8; std::mem::size_of::<CaFormatHeader>() + std::mem::size_of::<CaFormatEntry>()];
let mut header = crate::tools::map_struct_mut::<CaFormatHeader>(&mut buffer)?;
header.size = u64::to_le((std::mem::size_of::<CaFormatHeader>() + std::mem::size_of::<CaFormatEntry>()) as u64);
header.htype = u64::to_le(CA_FORMAT_ENTRY);
let mut entry = crate::tools::map_struct_mut::<CaFormatEntry>(&mut buffer[std::mem::size_of::<CaFormatHeader>()..])?;
entry.feature_flags = u64::to_le(CA_FORMAT_FEATURE_FLAGS_MAX);
if (stat.st_mode & libc::S_IFMT) == libc::S_IFLNK {
entry.mode = u64::to_le((libc::S_IFLNK | 0o777) as u64);
let mode = if (stat.st_mode & libc::S_IFMT) == libc::S_IFLNK {
(libc::S_IFLNK | 0o777) as u64
} else {
let mode = stat.st_mode & (libc::S_IFMT | 0o7777);
entry.mode = u64::to_le(mode as u64);
}
entry.flags = 0; // todo: CHATTR, FAT_ATTRS, subvolume?
entry.uid = u64::to_le(stat.st_uid as u64);
entry.gid = u64::to_le(stat.st_gid as u64);
(stat.st_mode & (libc::S_IFMT | 0o7777)) as u64
};
let mtime = stat.st_mtime * 1_000_000_000 + stat.st_mtime_nsec;
if mtime > 0 { entry.mtime = mtime as u64 };
if mtime < 0 {
bail!("got strange mtime ({}) from fstat for {:?}.", mtime, self.current_path);
}
self.write(&buffer)?;
let entry = CaFormatEntry {
feature_flags: CA_FORMAT_FEATURE_FLAGS_MAX, // fixme: ??
mode: mode,
flags: 0,
uid: stat.st_uid as u64,
gid: stat.st_gid as u64,
mtime: mtime as u64,
};
Ok(entry)
}
fn read_chattr(&self, fd: RawFd, entry: &mut CaFormatEntry) -> Result<(), Error> {
if let Some(fs_attr) = read_chattr(fd)? {
let flags = ca_feature_flags_from_chattr(fs_attr);
entry.flags = entry.flags | flags;
}
Ok(())
}
fn write_entry(&mut self, entry: &CaFormatEntry) -> Result<(), Error> {
self.write_header(CA_FORMAT_ENTRY, std::mem::size_of::<CaFormatEntry>() as u64)?;
self.write_item(entry)?;
Ok(())
}
@ -160,7 +196,7 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
Ok(())
}
fn encode_dir(&mut self, dir: &mut nix::dir::Dir) -> Result<(), Error> {
fn encode_dir(&mut self, dir: &mut nix::dir::Dir, dir_stat: &FileStat) -> Result<(), Error> {
//println!("encode_dir: {:?} start {}", self.current_path, self.writer_pos);
@ -168,18 +204,13 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
let rawfd = dir.as_raw_fd();
let dir_stat = match nix::sys::stat::fstat(rawfd) {
Ok(stat) => stat,
Err(err) => bail!("fstat {:?} failed - {}", self.current_path, err),
};
if (dir_stat.st_mode & libc::S_IFMT) != libc::S_IFDIR {
bail!("got unexpected file type {:?} (not a directory)", self.current_path);
}
let dir_start_pos = self.writer_pos;
self.write_entry(&dir_stat)?;
let mut dir_entry = self.create_entry(&dir_stat)?;
self.read_chattr(rawfd, &mut dir_entry)?;
self.write_entry(&dir_entry)?;
let mut dir_count = 0;
@ -201,22 +232,25 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
if name_len == 2 && name[0] == b'.' && name[1] == 0u8 { continue; }
if name_len == 3 && name[0] == b'.' && name[1] == b'.' && name[2] == 0u8 { continue; }
match nix::sys::stat::fstatat(rawfd, filename.as_ref(), nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
Ok(stat) => {
name_list.push((filename, stat));
}
Err(nix::Error::Sys(Errno::ENOENT)) => self.report_vanished_file(&self.current_path)?,
Err(err) => bail!("fstat {:?} failed - {}", self.current_path, err),
}
name_list.push(filename);
}
name_list.sort_unstable_by(|a, b| a.0.cmp(&b.0));
name_list.sort_unstable_by(|a, b| a.cmp(&b));
let mut goodbye_items = vec![];
for (filename, stat) in &name_list {
for filename in &name_list {
self.current_path.push(std::ffi::OsStr::from_bytes(filename.as_bytes()));
let stat = match nix::sys::stat::fstatat(rawfd, filename.as_ref(), nix::fcntl::AtFlags::AT_SYMLINK_NOFOLLOW) {
Ok(stat) => stat,
Err(nix::Error::Sys(Errno::ENOENT)) => {
self.report_vanished_file(&self.current_path)?;
continue;
}
Err(err) => bail!("fstat {:?} failed - {}", self.current_path, err),
};
let start_pos = self.writer_pos;
self.write_filename(&filename)?;
@ -224,7 +258,7 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
if (stat.st_mode & libc::S_IFMT) == libc::S_IFDIR {
match nix::dir::Dir::openat(rawfd, filename.as_ref(), OFlag::O_NOFOLLOW, Mode::empty()) {
Ok(mut dir) => self.encode_dir(&mut dir)?,
Ok(mut dir) => self.encode_dir(&mut dir, &stat)?,
Err(nix::Error::Sys(Errno::ENOENT)) => self.report_vanished_file(&self.current_path)?,
Err(err) => bail!("open dir {:?} failed - {}", self.current_path, err),
}
@ -232,7 +266,7 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
} else if (stat.st_mode & libc::S_IFMT) == libc::S_IFREG {
match nix::fcntl::openat(rawfd, filename.as_ref(), OFlag::O_NOFOLLOW, Mode::empty()) {
Ok(filefd) => {
let res = self.encode_file(filefd);
let res = self.encode_file(filefd, &stat);
let _ = nix::unistd::close(filefd); // ignore close errors
res?;
}
@ -285,20 +319,15 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
Ok(())
}
fn encode_file(&mut self, filefd: RawFd) -> Result<(), Error> {
fn encode_file(&mut self, filefd: RawFd, stat: &FileStat) -> Result<(), Error> {
//println!("encode_file: {:?}", self.current_path);
let stat = match nix::sys::stat::fstat(filefd) {
Ok(stat) => stat,
Err(err) => bail!("fstat {:?} failed - {}", self.current_path, err),
};
let mut entry = self.create_entry(&stat)?;
if (stat.st_mode & libc::S_IFMT) != libc::S_IFREG {
bail!("got unexpected file type {:?} (not a regular file)", self.current_path);
}
self.read_chattr(filefd, &mut entry)?;
self.write_entry(&stat)?;
self.write_entry(&entry)?;
let size = stat.st_size as u64;
@ -339,7 +368,8 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
//println!("encode_symlink: {:?} -> {:?}", self.current_path, target);
self.write_entry(stat)?;
let entry = self.create_entry(&stat)?;
self.write_entry(&entry)?;
self.write_header(CA_FORMAT_SYMLINK, target.len() as u64)?;
self.write(target)?;
@ -356,3 +386,33 @@ impl <'a, W: Write> CaTarEncoder<'a, W> {
Ok(())
}
}
fn errno_is_unsupported(errno: Errno) -> bool {
match errno {
Errno::ENOTTY | Errno::ENOSYS | Errno::EBADF | Errno::EOPNOTSUPP | Errno::EINVAL => {
true
}
_ => false,
}
}
use nix::{convert_ioctl_res, request_code_read, ioc};
// /usr/include/linux/fs.h: #define FS_IOC_GETFLAGS _IOR('f', 1, long)
/// read Linux file system attributes (see man chattr)
nix::ioctl_read!(read_attr_fd, b'f', 1, usize);
fn read_chattr(rawfd: RawFd) -> Result<Option<u32>, Error> {
let mut attr: usize = 0;
let res = unsafe { read_attr_fd(rawfd, &mut attr)};
if let Err(err) = res {
if let nix::Error::Sys(errno) = err {
if errno_is_unsupported(errno) { return Ok(None) };
}
bail!("read_attr_fd failed - {}", err);
}
Ok(Some(attr as u32))
}

61
src/catar/format_definition.rs
View File

@ -19,9 +19,29 @@ pub const CA_FORMAT_GOODBYE: u64 = 0xdfd35c5e8327c403;
/* The end marker used in the GOODBYE object */
pub const CA_FORMAT_GOODBYE_TAIL_MARKER: u64 = 0x57446fa533702943;
// Feature flags
// DOS file flags
pub const CA_FORMAT_WITH_FLAG_HIDDEN: u64 = 0x2000;
pub const CA_FORMAT_WITH_FLAG_SYSTEM: u64 = 0x4000;
pub const CA_FORMAT_WITH_FLAG_ARCHIVE: u64 = 0x8000;
// chattr() flags
pub const CA_FORMAT_WITH_FLAG_APPEND: u64 = 0x10000;
pub const CA_FORMAT_WITH_FLAG_NOATIME: u64 = 0x20000;
pub const CA_FORMAT_WITH_FLAG_COMPR: u64 = 0x40000;
pub const CA_FORMAT_WITH_FLAG_NOCOW: u64 = 0x80000;
pub const CA_FORMAT_WITH_FLAG_NODUMP: u64 = 0x100000;
pub const CA_FORMAT_WITH_FLAG_DIRSYNC: u64 = 0x200000;
pub const CA_FORMAT_WITH_FLAG_IMMUTABLE: u64 = 0x400000;
pub const CA_FORMAT_WITH_FLAG_SYNC: u64 = 0x800000;
pub const CA_FORMAT_WITH_FLAG_NOCOMP: u64 = 0x1000000;
pub const CA_FORMAT_WITH_FLAG_PROJINHERIT: u64 = 0x2000000;
pub const CA_FORMAT_FEATURE_FLAGS_MAX: u64 = 0xb000_0001_ffef_fe26; // fixme: ?
#[derive(Endian)]
#[derive(Endian,Clone)]
#[repr(C)]
pub struct CaFormatHeader {
/// The size of the item, including the size of `CaFormatHeader`.
@ -30,7 +50,7 @@ pub struct CaFormatHeader {
pub htype: u64,
}
#[derive(Endian)]
#[derive(Endian,Clone)]
#[repr(C)]
pub struct CaFormatEntry {
pub feature_flags: u64,
@ -93,3 +113,40 @@ pub fn check_ca_header<T>(head: &CaFormatHeader, htype: u64) -> Result<(), Error
Ok(())
}
// form /usr/include/linux/fs.h
const FS_APPEND_FL: u32 = 0x00000020;
const FS_NOATIME_FL: u32 = 0x00000080;
const FS_COMPR_FL: u32 = 0x00000004;
const FS_NOCOW_FL: u32 = 0x00800000;
const FS_NODUMP_FL: u32 = 0x00000040;
const FS_DIRSYNC_FL: u32 = 0x00010000;
const FS_IMMUTABLE_FL: u32 = 0x00000010;
const FS_SYNC_FL: u32 = 0x00000008;
const FS_NOCOMP_FL: u32 = 0x00000400;
const FS_PROJINHERIT_FL: u32 = 0x20000000;
static CHATTR_MAP: [(u64, u32); 10] = [
( CA_FORMAT_WITH_FLAG_APPEND, FS_APPEND_FL ),
( CA_FORMAT_WITH_FLAG_NOATIME, FS_NOATIME_FL ),
( CA_FORMAT_WITH_FLAG_COMPR, FS_COMPR_FL ),
( CA_FORMAT_WITH_FLAG_NOCOW, FS_NOCOW_FL ),
( CA_FORMAT_WITH_FLAG_NODUMP, FS_NODUMP_FL ),
( CA_FORMAT_WITH_FLAG_DIRSYNC, FS_DIRSYNC_FL ),
( CA_FORMAT_WITH_FLAG_IMMUTABLE, FS_IMMUTABLE_FL ),
( CA_FORMAT_WITH_FLAG_SYNC, FS_SYNC_FL ),
( CA_FORMAT_WITH_FLAG_NOCOMP, FS_NOCOMP_FL ),
( CA_FORMAT_WITH_FLAG_PROJINHERIT, FS_PROJINHERIT_FL ),
];
pub fn ca_feature_flags_from_chattr(attr: u32) -> u64 {
let mut flags = 0u64;
for (ca_flag, fs_flag) in &CHATTR_MAP {
if (attr & fs_flag) != 0 { flags = flags | ca_flag; }
}
flags
}