Merge branch 'relibc' into 'master'

Implement 'tar.h' See merge request redox-os/relibc!588
2024-12-20 14:27:31 +00:00
parent 41c88ed288 ff66c10a27
commit a4ba9cf0ad
3 changed files with 158 additions and 1 deletions
@@ -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)
@@ -0,0 +1,10 @@
+sys_includes = ["sys/types.h"]
+include_guard = "_TAR_H"
+trailer = "#include <bits/tar.h>"
+language = "C"
+style = "Tag"
+no_includes = true
+cpp_compat = true
+
+[enum]
+prefix_with_name = true
@@ -0,0 +1,147 @@
+//! tar.h implementation for Redox, following POSIX.1-1990 specification
+//!  and https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/tar.h.html
+
+use core::slice;
+
+/// Block size for tar archives (512 bytes).
+pub const BLOCKSIZE: usize = 512;
+
+/// Default record size for tar archives (10KB, consisting of 20 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
+
+/// Represents a tar archive header following the POSIX ustar format.
+///
+/// The header contains metadata about a file in a tar archive, including
+/// its name, size, permissions, and other attributes. All text fields are
+/// null-terminated.
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+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 {
+        let mut header = 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: AREGTYPE,
+            linkname: [0; LINKNAME_SIZE],
+            magic: [0; MAGIC_SIZE],
+            version: [0; VERSION_SIZE],
+            uname: [0; UNAME_SIZE],
+            gname: [0; GNAME_SIZE],
+            devmajor: [0; DEVMAJOR_SIZE],
+            devminor: [0; DEVMINOR_SIZE],
+            prefix: [0; PREFIX_SIZE],
+            padding: [0; 12],
+        };
+
+        // Set default magic ("ustar") and version ("00")
+        let magic_bytes = TMAGIC.as_bytes(); // "ustar"
+        header.magic[..magic_bytes.len()].copy_from_slice(magic_bytes);
+        // tar specification often expects "ustar\0"
+        if MAGIC_SIZE >= 6 && TMAGIC.len() < MAGIC_SIZE {
+            header.magic[TMAGIC.len()] = 0;
+        }
+
+        let version_bytes = TVERSION.as_bytes(); // "00"
+        header.version[..version_bytes.len()].copy_from_slice(version_bytes);
+
+        header
+    }
+}
+
+impl TarHeader {
+    /// 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;
+        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()
+    }
+}