Use memmem for finding needle in haystack

native/src/base/misc.rs

@@ -78,11 +78,40 @@ impl<T> LibcReturn for *mut T {
  }
 }
 
+pub trait BytesExt {
+ fn find(&self, needle: &[u8]) -> Option<usize>;
+ fn contains(&self, needle: &[u8]) -> bool {
+ self.find(needle).is_some()
+ }
+}
+
+impl<T: AsRef<[u8]> + ?Sized> BytesExt for T {
+ fn find(&self, needle: &[u8]) -> Option<usize> {
+ fn inner(haystack: &[u8], needle: &[u8]) -> Option<usize> {
+ unsafe {
+ let ptr: *const u8 = libc::memmem(
+ haystack.as_ptr().cast(),
+ haystack.len(),
+ needle.as_ptr().cast(),
+ needle.len(),
+ )
+ .cast();
+ if ptr.is_null() {
+ None
+ } else {
+ Some(ptr.offset_from(haystack.as_ptr()) as usize)
+ }
+ }
+ }
+ inner(self.as_ref(), needle)
+ }
+}
+
 pub trait MutBytesExt {
  fn patch(&mut self, from: &[u8], to: &[u8]) -> Vec<usize>;
 }
 
-impl<T: AsMut<[u8]>> MutBytesExt for T {
+impl<T: AsMut<[u8]> + ?Sized> MutBytesExt for T {
  fn patch(&mut self, from: &[u8], to: &[u8]) -> Vec<usize> {
  ffi::mut_u8_patch(self.as_mut(), from, to)
  }

native/src/boot/cpio.rs

@@ -21,8 +21,8 @@ use base::libc::{
  S_IWOTH, S_IWUSR, S_IXGRP, S_IXOTH, S_IXUSR,
 };
 use base::{
- log_err, map_args, EarlyExitExt, FsPath, LoggedResult, MappedFile, ResultExt, Utf8CStr,
- WriteExt,
+ log_err, map_args, BytesExt, EarlyExitExt, FsPath, LoggedResult, MappedFile, ResultExt,
+ Utf8CStr, WriteExt,
 };
 
 use crate::ffi::{unxz, xz};
@@ -246,7 +246,7 @@ impl Cpio {
  continue;
  }
  if name == "TRAILER!!!" {
- match data[pos..].windows(6).position(|x| x == b"070701") {
+ match data[pos..].find(b"070701") {
  Some(x) => pos += x,
  None => break,
  }