From a4cd0891892d5216d423b1e16cec5da4fa993c40 Mon Sep 17 00:00:00 2001 From: gugz0r Date: Wed, 18 Dec 2024 22:11:33 +0100 Subject: [PATCH] Implement 'tar.h' --- src/header/mod.rs | 2 +- src/header/tar/cbindgen.toml | 10 ++ src/header/tar/mod.rs | 216 +++++++++++++++++++++++++++++++++++ 3 files changed, 227 insertions(+), 1 deletion(-) create mode 100644 src/header/tar/cbindgen.toml create mode 100644 src/header/tar/mod.rs diff --git a/src/header/mod.rs b/src/header/mod.rs index a5f9db6498..b7978ba88f 100644 --- a/src/header/mod.rs +++ b/src/header/mod.rs @@ -102,7 +102,7 @@ pub mod sys_un; pub mod sys_utsname; pub mod sys_wait; // TODO: syslog.h -// TODO: tar.h +pub mod tar; // TODO: term.h (deprecated) pub mod termios; // TODO: tgmath.h (likely C implementation) diff --git a/src/header/tar/cbindgen.toml b/src/header/tar/cbindgen.toml new file mode 100644 index 0000000000..f881be9701 --- /dev/null +++ b/src/header/tar/cbindgen.toml @@ -0,0 +1,10 @@ +sys_includes = ["sys/types.h"] +include_guard = "_TAR_H" +trailer = "#include " +language = "C" +style = "Tag" +no_includes = true +cpp_compat = true + +[enum] +prefix_with_name = true \ No newline at end of file diff --git a/src/header/tar/mod.rs b/src/header/tar/mod.rs new file mode 100644 index 0000000000..92e51a5efc --- /dev/null +++ b/src/header/tar/mod.rs @@ -0,0 +1,216 @@ +/// tar.h implementation for Redox, following https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/tar.h.html +use core::slice; + +/// Archive block size +pub const BLOCKSIZE: usize = 512; // Block size in bytes + +/// Default record size (512 blocks) +pub const RECORDSIZE: usize = BLOCKSIZE * 20; // 10KB (default for tar archives) + +/// Field lengths in tar headers +pub const NAME_SIZE: usize = 100; // File name +pub const MODE_SIZE: usize = 8; // File mode +pub const UID_SIZE: usize = 8; // Owner's numeric user ID +pub const GID_SIZE: usize = 8; // Group's numeric user ID +pub const SIZE_SIZE: usize = 12; // File size in bytes +pub const MTIME_SIZE: usize = 12; // Modification time +pub const CHKSUM_SIZE: usize = 8; // Checksum +pub const LINKNAME_SIZE: usize = 100; // Name of linked file +pub const MAGIC_SIZE: usize = 6; // Magic string size +pub const VERSION_SIZE: usize = 2; // Version string size +pub const UNAME_SIZE: usize = 32; // Owner user name +pub const GNAME_SIZE: usize = 32; // Owner group name +pub const DEVMAJOR_SIZE: usize = 8; // Major device number +pub const DEVMINOR_SIZE: usize = 8; // Minor device number +pub const PREFIX_SIZE: usize = 155; // Prefix for file name +pub const HEADER_SIZE: usize = 512; // Total header size + +/// Bits used in the mode field - value in octal +pub const TSUID: u16 = 0o4000; // Set user ID on execution +pub const TSGID: u16 = 0o2000; // Set group ID on execution +pub const TSVTX: u16 = 0o1000; // Sticky bit +pub const TUREAD: u16 = 0o0400; // Read permission, owner +pub const TUWRITE: u16 = 0o0200; // Write permission, owner +pub const TUEXEC: u16 = 0o0100; // Execute/search permission, owner +pub const TGREAD: u16 = 0o0040; // Read permission, group +pub const TGWRITE: u16 = 0o0020; // Write permission, group +pub const TGEXEC: u16 = 0o0010; // Execute/search permission, group +pub const TOREAD: u16 = 0o0004; // Read permission, others +pub const TOWRITE: u16 = 0o0002; // Write permission, others +pub const TOEXEC: u16 = 0o0001; // Execute/search permission, others + +/// Values used in typeflag field +pub const REGTYPE: u8 = b'0'; // Regular file +pub const AREGTYPE: u8 = b'\0'; // Regular file (old format) +pub const LNKTYPE: u8 = b'1'; // Link +pub const SYMTYPE: u8 = b'2'; // Symbolic link +pub const CHRTYPE: u8 = b'3'; // Character special +pub const BLKTYPE: u8 = b'4'; // Block special +pub const DIRTYPE: u8 = b'5'; // Directory +pub const FIFOTYPE: u8 = b'6'; // FIFO special +pub const CONTTYPE: u8 = b'7'; // Contiguous file + +/// tar format magic and version +pub const TMAGIC: &str = "ustar"; // Magic string : ustar and a null +pub const TMAGLEN: usize = 6; // Length of the magic string +pub const TVERSION: &str = "00"; // Version string +pub const TVERSLEN: usize = 2; // Length of the version string + +/// Reserved for future standards +pub const XHDRTYPE: u8 = b'x'; // Extended header referring to the next file in the archive +pub const XGLTYPE: u8 = b'g'; // Global extended header + +/// Reserved values for GNU tar extensions +pub const GNUTYPE_DUMPDIR: u8 = b'D'; // Directory dump +pub const GNUTYPE_MULTIVOL: u8 = b'M'; // Multi-volume file +pub const GNUTYPE_LONGNAME: u8 = b'L'; // Long file name +pub const GNUTYPE_LONGLINK: u8 = b'K'; // Long link name +pub const GNUTYPE_SPARSE: u8 = b'S'; // Sparse file + +pub struct TarHeaderBuilder { + header: TarHeader, +} + +impl TarHeaderBuilder { + pub fn new() -> Self { + let mut header = TarHeader::default(); + header.magic.copy_from_slice(TMAGIC.as_bytes()); + header.version.copy_from_slice(TVERSION.as_bytes()); + Self { header } + } + + pub fn name(mut self, name: &str) -> Result { + self.header.name = TarHeader::to_null_terminated_field::(name)?; + Ok(self) + } + + pub fn build(self) -> TarHeader { + self.header + } +} + +#[repr(C)] +#[derive(Debug, Clone, Copy)] +/// tar header structure, from POSIX 1003.1-1990. +pub struct TarHeader { + // Byte offset - usage + pub name: [u8; NAME_SIZE], // 0 - File name + pub mode: [u8; MODE_SIZE], // 100 - Permissions + pub uid: [u8; UID_SIZE], // 108 - User ID + pub gid: [u8; GID_SIZE], // 116 - Group ID + pub size: [u8; SIZE_SIZE], // 124 - File size in bytes + pub mtime: [u8; MTIME_SIZE], // 136 - Modification time + pub chksum: [u8; CHKSUM_SIZE], // 148 - Header checksum + pub typeflag: u8, // 156 - File type + pub linkname: [u8; LINKNAME_SIZE], // 157 - Linked file name + pub magic: [u8; MAGIC_SIZE], // 257 - UStar magic + pub version: [u8; VERSION_SIZE], // 263 - UStar version + pub uname: [u8; UNAME_SIZE], // 265 - Owner user name + pub gname: [u8; GNAME_SIZE], // 297 - Owner group name + pub devmajor: [u8; DEVMAJOR_SIZE], // 329 - Major device number + pub devminor: [u8; DEVMINOR_SIZE], // 337 - Minor device number + pub prefix: [u8; PREFIX_SIZE], // 345 - Prefix for file name + pub padding: [u8; 12], // 500 - Padding to make 512 bytes +} + +impl Default for TarHeader { + fn default() -> Self { + Self { + name: [0; NAME_SIZE], + mode: [0; MODE_SIZE], + uid: [0; UID_SIZE], + gid: [0; GID_SIZE], + size: [0; SIZE_SIZE], + mtime: [0; MTIME_SIZE], + chksum: [0; CHKSUM_SIZE], + typeflag: REGTYPE, // Default to regular file type + linkname: [0; LINKNAME_SIZE], + magic: *b"ustar\0", // UStar magic string + version: *b"00", // UStar version + uname: [0; UNAME_SIZE], + gname: [0; GNAME_SIZE], + devmajor: [0; DEVMAJOR_SIZE], + devminor: [0; DEVMINOR_SIZE], + prefix: [0; PREFIX_SIZE], + padding: [0; 12], + } + } +} + +impl TarHeader { + /// Converts a byte array field to a string, trimming null bytes. + pub fn to_str(field: &[u8]) -> Option<&str> { + let end = field.iter().position(|&b| b == 0).unwrap_or(field.len()); + core::str::from_utf8(&field[..end]).ok() + } + + /// Converts a string to a null-terminated byte array for a field. + pub fn to_null_terminated_field(s: &str) -> Result<[u8; N], TarError> { + let mut field = [0u8; N]; + let bytes = s.as_bytes(); + if bytes.len() >= N { + return Err(TarError::FieldTooLong); + } + field[..bytes.len()].copy_from_slice(bytes); + Ok(field) + } + + /// Validate the checksum + pub fn validate(&self) -> Result<(), TarError> { + let recorded_checksum = match TarHeader::to_str(&self.chksum) { + Some(cs) => { + usize::from_str_radix(cs.trim_end(), 8).map_err(|_| TarError::InvalidChecksum)? + } + None => return Err(TarError::InvalidChecksum), + }; + + // Calculate actual checksum + let mut header_copy = *self; + + // Set checksum field to spaces for calculation + header_copy.chksum.fill(b' '); + + let actual_checksum: usize = unsafe { + core::slice::from_raw_parts(&header_copy as *const _ as *const u8, HEADER_SIZE) + } + .iter() + .map(|&x| x as usize) + .sum(); + + if actual_checksum != recorded_checksum { + return Err(TarError::InvalidChecksum); + } + Ok(()) + } + + pub fn builder() -> TarHeaderBuilder { + TarHeaderBuilder::new() + } + + pub fn file_type(&self) -> &'static str { + match self.typeflag { + REGTYPE | AREGTYPE => "Regular File", + DIRTYPE => "Directory", + SYMTYPE => "Symbolic Link", + LNKTYPE => "Hard Link", + CHRTYPE => "Character Device", + BLKTYPE => "Block Device", + FIFOTYPE => "FIFO", + CONTTYPE => "Contiguous File", + _ => "Unknown", + } + } + + +} + +#[derive(Debug)] +pub enum TarError { + InvalidChecksum, + IoError, + InvalidHeader, + UnknownTypeFlag(u8), + InvalidEncoding, // Check for UTF-8 conversion errors + FieldTooLong, // Checks when input strings exceed field sizes +} +