hpk/src/tar/header.rs

495 lines
15 KiB
Rust

#![allow(clippy::similar_names)]
use crate::tar::Error;
use deku::prelude::*;
use std::{
env,
ffi::{CStr, OsStr},
fmt::{self, Write},
fs::{self, Metadata},
io,
ops::Deref,
os::unix::fs::FileTypeExt,
path::PathBuf,
};
#[cfg(target_os = "linux")]
use std::os::linux::fs::MetadataExt;
#[cfg(target_os = "freebsd")]
use std::os::freebsd::fs::MetadataExt;
#[repr(u8)]
pub enum FileType {
Normal = 0x30,
Hardlink = 0x31,
Symlink = 0x32,
Char = 0x33,
Block = 0x34,
Dir = 0x35,
FIFO = 0x36,
Unknown = 0x00,
}
impl<T> From<T> for FileType
where
T: Deref<Target = Metadata>,
{
fn from(meta: T) -> Self {
if meta.is_dir() {
return FileType::Dir;
}
let file_type = meta.file_type();
if file_type.is_fifo() {
return FileType::FIFO;
} else if file_type.is_char_device() {
return FileType::Char;
} else if file_type.is_block_device() {
return FileType::Block;
} else if file_type.is_symlink() {
return FileType::Symlink;
} else if file_type.is_file() {
return FileType::Normal;
}
FileType::Unknown
}
}
#[derive(Clone)]
pub struct Owner {
pub uid: u32,
pub gid: u32,
pub username: String,
pub groupname: String,
}
impl Default for Owner {
fn default() -> Self {
Self {
uid: 0,
gid: 0,
username: "root".into(),
groupname: "root".into(),
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, DekuRead, DekuWrite)]
#[deku(endian = "little")]
pub struct Header {
pub(crate) fname: [u8; 100],
pub(crate) mode: [u8; 8],
pub(crate) uid: [u8; 8],
pub(crate) gid: [u8; 8],
pub(crate) size: [u8; 12],
pub(crate) mtime: [u8; 12],
pub(crate) header_checksum: [u8; 8],
pub(crate) link_indicator: [u8; 1],
pub(crate) link_name: [u8; 100],
pub(crate) ustar_magic: [u8; 6],
pub(crate) ustar_version: [u8; 2],
pub(crate) username: [u8; 32],
pub(crate) groupname: [u8; 32],
pub(crate) device_major: [u8; 8],
pub(crate) device_minor: [u8; 8],
pub(crate) file_prefix: [u8; 155],
pub(crate) reserved: [u8; 12],
}
impl Default for Header {
fn default() -> Self {
Self {
fname: [0; 100],
mode: [0; 8],
uid: [0; 8],
gid: [0; 8],
size: [0; 12],
mtime: [0; 12],
header_checksum: [0x20; 8],
link_indicator: [0; 1],
link_name: [0; 100],
ustar_magic: [0x75, 0x73, 0x74, 0x61, 0x72, 0x20],
ustar_version: [0x20, 0x00],
username: [0; 32],
groupname: [0; 32],
device_major: [0; 8],
device_minor: [0; 8],
file_prefix: [0; 155],
reserved: [0; 12],
}
}
}
impl Header {
/// Get the filename of this archive member
///
/// # Example
///
/// ```
/// use hpk::tar::Header;
///
/// let header = Header::new("test/1.txt").unwrap();
/// let filename = header.filename().unwrap();
/// assert_eq!(filename.as_str(), "test/1.txt");
/// ```
pub fn filename(&self) -> Result<String, fmt::Error> {
let mut s = String::new();
for c in self.fname {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
Ok(s)
}
/// Gets the Unix mode of this archive member
///
/// # Example
/// ```
/// use hpk::tar::Header;
///
/// let header = Header::new("test/1.txt").unwrap();
/// let mode = header.mode().unwrap();
/// assert_eq!(mode, 420);
/// ```
pub fn mode(&self) -> Result<u32, Error> {
let mut s = String::new();
for c in self.mode {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
let mode = u32::from_str_radix(&s, 8)?;
Ok(mode)
}
fn uid(&self) -> Result<u32, Error> {
let mut s = String::new();
for c in self.mode {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
let uid = u32::from_str_radix(&s, 8)?;
Ok(uid)
}
fn gid(&self) -> Result<u32, Error> {
let mut s = String::new();
for c in self.mode {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
let gid = u32::from_str_radix(&s, 8)?;
Ok(gid)
}
fn username(&self) -> Result<String, fmt::Error> {
let mut s = String::new();
for c in self.username {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
Ok(s)
}
fn groupname(&self) -> Result<String, fmt::Error> {
let mut s = String::new();
for c in self.groupname {
if c == 0 {
break;
}
write!(s, "{}", char::from(c))?;
}
Ok(s)
}
pub fn owner(&self) -> Result<Owner, Error> {
let uid = self.uid()?;
let gid = self.gid()?;
let username = self.username()?;
let groupname = self.groupname()?;
Ok(Owner {
uid,
gid,
username,
groupname,
})
}
/// Gets the path to the file minus it's final component
/// > Note: the ustar format only uses this field if the
/// > complete filename would be longer than 100 bytes.
/// > If the combined filename is shorter, this function
/// > returns `None`.
///
/// # Example
/// ```
/// use hpk::tar::Header;
///
/// let header = Header::new("test/1.txt").unwrap();
/// let prefix = header.prefix();
/// assert!(prefix.is_none());
/// ```
pub fn prefix(&self) -> Option<String> {
let mut s = String::new();
for c in self.file_prefix {
if c == 0 {
break;
}
write!(s, "{}", char::from(c)).ok()?;
}
if s.is_empty() {
None
} else {
Some(s)
}
}
/// Gets the full file path to this archive member.
///
/// # Example
///
/// ```
/// use hpk::tar::Header;
/// use std::path::PathBuf;
///
/// let header = Header::new("test/1.txt").unwrap();
/// let path = header.file_path().unwrap();
/// assert_eq!(PathBuf::from("test/1.txt"), path);
/// ```
pub fn file_path(&self) -> Result<PathBuf, fmt::Error> {
let mut path = match self.prefix() {
Some(p) => PathBuf::from(&p),
None => PathBuf::new(),
};
let name = self.filename()?;
path.push(&name);
Ok(path)
}
#[allow(clippy::missing_panics_doc)]
pub fn new(filename: &str) -> Result<Self, Error> {
let mut header = Header::default();
let meta = fs::symlink_metadata(filename)?;
let (filename, prefix) = {
// Original tar has a maximum file name length of 100 bytes. The ustar
// revision allows storing the path prefix separately if the combined
// length is more than 100 bytes.
if filename.len() > 100 {
let path = PathBuf::from(&filename);
let name = match path.file_name().and_then(OsStr::to_str) {
Some(n) => n.to_string(),
None => {
return Err(Error::Io(io::Error::new(
io::ErrorKind::Other,
"Cannot get file name",
)))
}
};
let dir = path.parent().map(|x| format!("{}", x.display()));
(name, dir)
} else {
(filename.to_string(), None)
}
};
/* Fill in metadata */
header.fname[..filename.len()].copy_from_slice(filename.as_bytes());
let mode = format!("{:07o}", (meta.st_mode() & 0o777));
header.mode[..mode.len()].copy_from_slice(mode.as_bytes());
let user = format!("{:07o}", meta.st_uid());
header.uid[..user.len()].copy_from_slice(user.as_bytes());
let group = format!("{:07o}", meta.st_gid());
header.gid[..group.len()].copy_from_slice(group.as_bytes());
let size = format!("{:011o}", meta.st_size());
header.size[..size.len()].copy_from_slice(size.as_bytes());
let mtime = format!("{:011o}", meta.st_mtime());
header.mtime[..mtime.len()].copy_from_slice(mtime.as_bytes());
if let Some(prefix) = prefix {
header.file_prefix[..prefix.len()].copy_from_slice(prefix.as_bytes());
}
/* Get the file type and conditional metadata */
header.link_indicator[0] = FileType::from(&meta) as u8;
if header.link_indicator[0] == FileType::Symlink as u8 {
let link = fs::read_link(filename)?.to_str().unwrap().to_string();
header.link_name[..link.len()].copy_from_slice(link.as_bytes());
} else if header.link_indicator[0] == FileType::Block as u8 {
let major = format!("{:07o}", meta.st_dev());
header.device_major[..major.len()].copy_from_slice(major.as_bytes());
let minor = format!("{:07o}", meta.st_rdev());
header.device_minor[..minor.len()].copy_from_slice(minor.as_bytes());
}
/* TODO: Find better way to get username */
let key = "USER";
if let Ok(val) = env::var(key) {
header.username[..val.len()].copy_from_slice(val.as_bytes());
}
/* TODO: Find way to get groupname */
/* Update the header checksum value */
header.update_checksum()?;
Ok(header)
}
#[allow(clippy::missing_panics_doc)]
pub fn new_from_meta(
filename: &str,
meta: &Metadata,
owner: Option<Owner>,
) -> Result<Self, Error> {
let mut header = Header::default();
let (filename, prefix) = {
// Original tar has a maximum file name length of 100 bytes. The ustar
// revision allows storing the path prefix separately if the combined
// length is more than 100 bytes.
if filename.len() > 100 {
let path = PathBuf::from(&filename);
let name = match path.file_name().and_then(OsStr::to_str) {
Some(n) => n.to_string(),
None => {
return Err(Error::Io(io::Error::new(
io::ErrorKind::Other,
"Cannot get file name",
)))
}
};
let dir = path.parent().map(|x| format!("{}", x.display()));
(name, dir)
} else {
(filename.to_string(), None)
}
};
header.fname[..filename.len()].copy_from_slice(filename.as_bytes());
let mode = format!("{:07o}", meta.st_mode());
header.mode[..mode.len()].copy_from_slice(mode.as_bytes());
let owner = match owner {
Some(o) => o,
None => Owner {
uid: meta.st_uid(),
gid: meta.st_gid(),
username: get_username_for_uid(meta.st_uid())?.into(),
groupname: get_groupname_for_gid(meta.st_gid())?.into(),
},
};
let uid = format!("{:07o}", owner.uid);
header.uid[..uid.len()].copy_from_slice(uid.as_bytes());
let gid = format!("{:07o}", owner.gid);
header.gid[..gid.len()].copy_from_slice(gid.as_bytes());
let size = format!("{:011o}", meta.len());
header.size[..size.len()].copy_from_slice(size.as_bytes());
let mtime = format!("{:011o}", meta.st_mtime());
header.mtime[..mtime.len()].copy_from_slice(mtime.as_bytes());
if let Some(prefix) = prefix {
header.file_prefix[..prefix.len()].copy_from_slice(prefix.as_bytes());
}
header.link_indicator[0] = FileType::from(meta) as u8;
if header.link_indicator[0] == FileType::Symlink as u8 {
let link = fs::read_link(filename)?.to_str().unwrap().to_string();
header.link_name[..link.len()].copy_from_slice(link.as_bytes());
} else if header.link_indicator[0] == FileType::Block as u8 {
let major = format!("{:07o}", meta.st_dev());
header.device_major[..major.len()].copy_from_slice(major.as_bytes());
let minor = format!("{:07o}", meta.st_rdev());
header.device_minor[..minor.len()].copy_from_slice(minor.as_bytes());
}
header.username[..owner.username.len()].copy_from_slice(owner.username.as_bytes());
header.groupname[..owner.groupname.len()].copy_from_slice(owner.groupname.as_bytes());
header.update_checksum()?;
Ok(header)
}
/// Validates that the magic value received matches the magic value required in the Tar specification.
///
/// # Example
///
/// ```
/// use hpk::tar::Header;
/// let header = Header::default();
/// if !header.validate_magic() {
/// println!("Magic value is invalid");
/// }
/// ```
pub fn validate_magic(self) -> bool {
self.ustar_magic == "ustar ".as_bytes()
}
/// Validates the header checksum computes to the expected value.
///
/// # Example
///
/// ```
/// use hpk::tar::Header;
/// let header = Header::default();
/// if header.validate_checksum().unwrap() {
/// println!("Checksum is valid");
/// }
/// ```
pub fn validate_checksum(self) -> Result<bool, Error> {
let mut test = self;
let mut new = [0x20u8; 8];
test.header_checksum.copy_from_slice(&[0x20; 8]);
let tmp = format!("{:06o}\x00", test.calc_checksum()?);
new[..tmp.len()].copy_from_slice(tmp.as_bytes());
Ok(self.header_checksum == new)
}
/// Updates the header checksum value.
///
/// # Example
///
/// ```
/// use hpk::tar::Header;
/// let mut header = Header::default();
///
/// /* Fill in header information */
///
/// header.update_checksum();
/// ```
pub fn update_checksum(&mut self) -> Result<(), Error> {
let checksum = format!("{:06o}\x00", self.calc_checksum()?);
self.header_checksum[..checksum.len()].copy_from_slice(checksum.as_bytes());
Ok(())
}
fn calc_checksum(self) -> Result<usize, Error> {
let out = self.to_bytes()?;
let mut checksum = 0;
for i in out {
checksum += i as usize;
}
Ok(checksum)
}
}
fn get_username_for_uid<'a>(uid: u32) -> Result<&'a str, std::str::Utf8Error> {
let user = unsafe {
let pw = libc::getpwuid(uid);
let name = (*pw).pw_name;
CStr::from_ptr(name)
};
user.to_str()
}
fn get_groupname_for_gid<'a>(gid: u32) -> Result<&'a str, std::str::Utf8Error> {
let group = unsafe {
let gr = libc::getgrgid(gid);
let name = (*gr).gr_name;
CStr::from_ptr(name)
};
group.to_str()
}