diff --git a/src/header/tar/mod.rs b/src/header/tar/mod.rs index 010b9c59e0..52dffe3e35 100644 --- a/src/header/tar/mod.rs +++ b/src/header/tar/mod.rs @@ -1,16 +1,8 @@ //! tar.h implementation for Redox, following POSIX.1-1990 specification //! and https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/tar.h.html -//! -//! This module provides functionality for working with tar archives, including -//! header creation, validation, and manipulation. It implements the POSIX.1-1990 -//! ustar format. - use core::slice; -#[cfg(test)] -mod tests; - /// Block size for tar archives (512 bytes). pub const BLOCKSIZE: usize = 512; @@ -71,11 +63,11 @@ pub const XHDRTYPE: u8 = b'x'; // Extended header referring to the next file in 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 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 /// Represents a tar archive header following the POSIX ustar format. /// @@ -105,39 +97,6 @@ pub struct TarHeader { pub padding: [u8; 12], // 500 - Padding to make 512 bytes } -pub struct TarHeaderBuilder { - header: TarHeader, -} - -impl TarHeaderBuilder { - /// Creates a new `TarHeaderBuilder` with default values. - 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 } - } - - /// Sets the name field in the tar header. - /// - /// # Arguments - /// - /// * `name` - A string slice that holds the name of the file. - /// - /// # Errors - /// - /// Returns `TarError::FieldTooLong` if the name exceeds the maximum allowed length. - pub fn name(mut self, name: &str) -> Result { - self.header.name = TarHeader::to_null_terminated_field::(name)?; - Ok(self) - } - - /// Builds and returns the `TarHeader`. - pub fn build(self) -> TarHeader { - self.header - } -} - impl Default for TarHeader { fn default() -> Self { let mut header = Self { @@ -148,10 +107,10 @@ impl Default for TarHeader { size: [0; SIZE_SIZE], mtime: [0; MTIME_SIZE], chksum: [0; CHKSUM_SIZE], - typeflag: REGTYPE, // Default to regular file type + typeflag: AREGTYPE, linkname: [0; LINKNAME_SIZE], - magic: *b"ustar\0", // UStar magic string - version: *b"00", // UStar version + magic: [0; MAGIC_SIZE], + version: [0; VERSION_SIZE], uname: [0; UNAME_SIZE], gname: [0; GNAME_SIZE], devmajor: [0; DEVMAJOR_SIZE], @@ -160,17 +119,14 @@ impl Default for TarHeader { padding: [0; 12], }; - // Set default magic and version + // Set default magic ("ustar") and version ("00") let magic_bytes = TMAGIC.as_bytes(); // "ustar" header.magic[..magic_bytes.len()].copy_from_slice(magic_bytes); - - // POSIX ustar magic expects a trailing null - // TMAGIC = "ustar" (5 chars) + '\0' = 6 chars total - if TMAGLEN == 6 { - header.magic[5] = 0; + // tar specification often expects "ustar\0" + if MAGIC_SIZE >= 6 && TMAGIC.len() < MAGIC_SIZE { + header.magic[TMAGIC.len()] = 0; } - // Set the version field to "00" let version_bytes = TVERSION.as_bytes(); // "00" header.version[..version_bytes.len()].copy_from_slice(version_bytes); @@ -179,120 +135,13 @@ impl Default for TarHeader { } impl TarHeader { - /// Converts a byte array field to a UTF-8 string, trimming null bytes. - /// - /// # Returns - /// - /// * `Some(&str)` - If the field contains valid UTF-8 data - /// * `None` - If the field contains invalid UTF-8 data - 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 suitable for a tar header field. - /// - /// # Arguments - /// - /// * `s` - The string to convert - /// - /// # Returns - /// - /// * `Ok([u8; N])` - The null-terminated byte array - /// * `Err(TarError)` - If the string is too long for the field - pub fn to_null_terminated_field(s: &str) -> Result<[u8; N], TarError> { - let mut field = [0u8; N]; - let bytes = s.as_bytes(); - - // Reserve one byte for the null terminator - if bytes.len() + 1 > N { - return Err(TarError::FieldTooLong); - } - - field[..bytes.len()].copy_from_slice(bytes); - field[bytes.len()] = 0; // Null terminator - - Ok(field) - } - - /// Calculates the checksum of the header according to the POSIX specification. - /// - /// The checksum is calculated by summing all bytes in the header, with the - /// checksum field itself treated as eight spaces (ASCII 32). - /// - /// # Returns - /// - /// The calculated checksum value + /// Calculates the checksum of the tar header as required by the specification. + /// Before computing, the checksum field is treated as if it contained all spaces (0x20). pub fn calculate_checksum(&self) -> usize { let mut header_copy = *self; - // Replace chksum field with spaces header_copy.chksum.fill(b' '); - let bytes = unsafe { slice::from_raw_parts(&header_copy as *const _ as *const u8, HEADER_SIZE) }; - bytes.iter().map(|&b| b as usize).sum() } - - /// Validates the header's stored checksum against a calculated checksum. - /// - /// # Returns - /// - /// * `Ok(())` - If the checksum is valid - /// * `Err(TarError)` - If the checksum is invalid or malformed - pub fn validate(&self) -> Result<(), TarError> { - let recorded_str = match TarHeader::to_str(&self.chksum) { - Some(cs) => cs.trim_end(), - None => return Err(TarError::InvalidChecksum), - }; - - let recorded_checksum = - usize::from_str_radix(recorded_str, 8).map_err(|_| TarError::InvalidChecksum)?; - - let actual_checksum = self.calculate_checksum(); - if actual_checksum != recorded_checksum { - return Err(TarError::InvalidChecksum); - } - Ok(()) - } - - /// Creates a new TarHeaderBuilder for constructing a TarHeader. - pub fn builder() -> TarHeaderBuilder { - TarHeaderBuilder::new() - } - - /// Returns a human-readable description of the file type. - /// - /// # Returns - /// - /// A string slice describing the type of file represented by this header. - 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 { - /// The checksum in the tar header is invalid. - InvalidChecksum, - /// An I/O error occurred. - IoError, - /// The tar header is invalid. - InvalidHeader, - /// The type flag in the tar header is unknown. - UnknownTypeFlag(u8), - /// An error occurred during UTF-8 conversion. - InvalidEncoding, - /// The input string exceeds the maximum allowed field size. - FieldTooLong, } diff --git a/src/header/tar/tests.rs b/src/header/tar/tests.rs deleted file mode 100644 index f94137f9b2..0000000000 --- a/src/header/tar/tests.rs +++ /dev/null @@ -1,79 +0,0 @@ -#[cfg(test)] -mod tests { - use super::*; - use crate::header::tar::{TarError, TarHeader, DIRTYPE, NAME_SIZE, SYMTYPE}; - - #[test] - fn test_header_checksum() { - let mut header = TarHeader::default(); - - // Set fields to valid octal strings for mode, size, mtime - // mode: 0000644 (octal), commonly used in tar archives - header.mode = *b"0000644\0"; - - // size: 12 chars total, octal "000000000123" fits exactly - // (no null terminator needed if fully used) - header.size = *b"000000000123"; - - // mtime: 12 chars total, octal time "00000001234\0" - // Counting chars: '0'(1)'0'(2)'0'(3)'0'(4)'0'(5)'0'(6)'0'(7)'1'(8)'2'(9)'3'(10)'4'(11)'\0'(12) - header.mtime = *b"00000001234\0"; - - // Calculate the checksum - let checksum = header.calculate_checksum(); - - // According to tar specification, the checksum field should contains - // an octal number followed by a null and a space if possible. - // For an 8-byte field: 6 octal digits, a null, and a space : - // - // Example: "000000\0 " (sum in octal) - let checksum_str = format!("{:06o}\0 ", checksum); - header.chksum.copy_from_slice(checksum_str.as_bytes()); - - assert!(header.validate().is_ok()); - } - - #[test] - fn test_header_builder() { - let header = TarHeader::builder().name("test/file.txt").unwrap().build(); - - // The builder sets a null terminator after "test/file.txt" - let expected = { - let mut arr = [0u8; NAME_SIZE]; - arr[.."test/file.txt".len()].copy_from_slice(b"test/file.txt"); - arr["test/file.txt".len()] = 0; - arr - }; - - assert_eq!(header.name, expected); - } - - #[test] - fn test_field_too_long() { - // NAME_SIZE = 100, so a string longer than 99 chars fails - let long_string = "a".repeat(200); - let result = TarHeader::to_null_terminated_field::(&long_string); - - assert!(matches!(result, Err(TarError::FieldTooLong))); - } - - #[test] - fn test_invalid_checksum() { - let mut header = TarHeader::default(); - // Set chksum to something invalid - header.chksum = *b"99999999"; // Not a valid octal, likely fails - assert!(header.validate().is_err()); - } - - #[test] - fn test_file_type() { - let mut header = TarHeader::default(); - assert_eq!(header.file_type(), "Regular File"); - - header.typeflag = DIRTYPE; - assert_eq!(header.file_type(), "Directory"); - - header.typeflag = SYMTYPE; - assert_eq!(header.file_type(), "Symbolic Link"); - } -}