94 lines
2.9 KiB
Rust
94 lines
2.9 KiB
Rust
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//! Wrapper functions for the libc xattr calls
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extern crate libc;
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use std::os::unix::io::RawFd;
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use nix::errno::Errno;
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use crate::pxar::{CaFormatXAttr, CaFormatFCaps};
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pub fn flistxattr(fd: RawFd) -> Result<Vec<u8>, nix::errno::Errno> {
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// Initial buffer size for the attribute list, if content does not fit
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// it gets dynamically increased until big enough.
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let mut size = 256;
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let mut buffer = vec![0u8; size];
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let mut bytes = unsafe {
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libc::flistxattr(fd, buffer.as_mut_ptr() as *mut i8, buffer.len())
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};
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while bytes < 0 {
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let err = Errno::last();
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match err {
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Errno::ERANGE => {
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// Buffer was not big enough to fit the list, retry with double the size
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if size * 2 < size { return Err(Errno::ENOMEM); }
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size *= 2;
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},
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_ => return Err(err),
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}
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// Retry to read the list with new buffer
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buffer.resize(size, 0);
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bytes = unsafe {
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libc::flistxattr(fd, buffer.as_mut_ptr() as *mut i8, buffer.len())
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};
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}
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buffer.resize(bytes as usize, 0);
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Ok(buffer)
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}
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pub fn fgetxattr(fd: RawFd, name: &[u8]) -> Result<Vec<u8>, nix::errno::Errno> {
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let mut size = 256;
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let mut buffer = vec![0u8; size];
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let mut bytes = unsafe {
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libc::fgetxattr(fd, name.as_ptr() as *const i8, buffer.as_mut_ptr() as *mut core::ffi::c_void, buffer.len())
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};
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while bytes < 0 {
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let err = Errno::last();
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match err {
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Errno::ERANGE => {
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// Buffer was not big enough to fit the value, retry with double the size
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if size * 2 < size { return Err(Errno::ENOMEM); }
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size *= 2;
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},
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_ => return Err(err),
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}
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buffer.resize(size, 0);
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bytes = unsafe {
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libc::fgetxattr(fd, name.as_ptr() as *const i8, buffer.as_mut_ptr() as *mut core::ffi::c_void, buffer.len())
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};
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}
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buffer.resize(bytes as usize, 0);
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Ok(buffer)
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}
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pub fn fsetxattr(fd: RawFd, xattr: CaFormatXAttr) -> Result<(), nix::errno::Errno> {
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let mut name = xattr.name.clone();
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name.push('\0' as u8);
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let flags = 0 as libc::c_int;
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let result = unsafe {
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libc::fsetxattr(fd, name.as_ptr() as *const libc::c_char, xattr.value.as_ptr() as *const libc::c_void, xattr.value.len(), flags)
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};
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if result < 0 {
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let err = Errno::last();
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return Err(err);
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}
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Ok(())
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}
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pub fn fsetxattr_fcaps(fd: RawFd, fcaps: CaFormatFCaps) -> Result<(), nix::errno::Errno> {
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// TODO casync checks and removes capabilities if they are set
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let name = b"security.capability\0";
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let flags = 0 as libc::c_int;
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let result = unsafe {
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libc::fsetxattr(fd, name.as_ptr() as *const libc::c_char, fcaps.data.as_ptr() as *const libc::c_void, fcaps.data.len(), flags)
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};
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if result < 0 {
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let err = Errno::last();
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return Err(err);
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}
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Ok(())
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}
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