Adding sed example for overriding the LD when not the same function is used

Author: ChrisDryden

src/uu/rm/locales/en-US.ftl

@@ -43,6 +43,7 @@ rm-error-dangerous-recursive-operation = it is dangerous to operate recursively
 rm-error-use-no-preserve-root = use --no-preserve-root to override this failsafe
 rm-error-refusing-to-remove-directory = refusing to remove '.' or '..' directory: skipping '{$path}'
 rm-error-cannot-remove = cannot remove {$file}
+rm-error-traversal-failed = traversal failed: {$path}
 
 # Verbose messages
 rm-verbose-removed = removed {$file}

src/uu/rm/src/platform/linux.rs

@@ -13,7 +13,7 @@ use std::fs;
 use std::path::Path;
 use uucore::display::Quotable;
 use uucore::error::FromIo;
-use uucore::safe_traversal::DirFd;
+use uucore::safe_traversal::{DirFd, clear_errno, take_errno};
 use uucore::show_error;
 use uucore::translate;
 
@@ -258,6 +258,7 @@ pub fn safe_remove_dir_recursive(
 
 pub fn safe_remove_dir_recursive_impl(path: &Path, dir_fd: &DirFd, options: &Options) -> bool {
     // Read directory entries using safe traversal
+    clear_errno();
     let entries = match dir_fd.read_dir() {
         Ok(entries) => entries,
         Err(e) if e.kind() == std::io::ErrorKind::PermissionDenied => {
@@ -271,6 +272,14 @@ pub fn safe_remove_dir_recursive_impl(path: &Path, dir_fd: &DirFd, options: &Opt
         }
     };
 
+    // Check if readdir failed partway through (partial read)
+    if let Some(err) = take_errno() {
+        if !entries.is_empty() {
+            show_error!("{}: {}", translate!("rm-error-traversal-failed", "path" => path.display()), err);
+            return true;
+        }
+    }
+
     let mut error = false;
 
     // Process each entry

src/uucore/src/lib/features/safe_traversal.rs

@@ -21,6 +21,7 @@ use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, OwnedFd, RawFd};
 use std::path::Path;
 
 use nix::dir::Dir;
+use nix::errno::Errno;
 use nix::fcntl::{OFlag, openat};
 use nix::libc;
 use nix::sys::stat::{FchmodatFlags, FileStat, Mode, fchmodat, fstatat};
@@ -78,6 +79,19 @@ impl From<SafeTraversalError> for io::Error {
     }
 }
 
+/// Clear errno and return any error that was set after an operation
+/// This is used because the nix library does not propogate folder reading errors correctly
+pub fn take_errno() -> Option<io::Error> {
+    let errno = Errno::last();
+    Errno::clear();
+    (errno != Errno::from_raw(0)).then(|| io::Error::from_raw_os_error(errno as i32))
+}
+
+/// Clear errno before an operation, required to read error messages not propogated by nix from reading folders
+pub fn clear_errno() {
+    Errno::clear();
+}
+
 // Helper function to read directory entries using nix
 fn read_dir_entries(fd: &OwnedFd) -> io::Result<Vec<OsString>> {
     let mut entries = Vec::new();

util/build-gnu.sh

@@ -361,3 +361,18 @@ test \$n_stat1 -ge \$n_stat2 \\' tests/ls/stat-free-color.sh
 # * the selinux crate is handling errors
 # * the test says "maybe we should not fail when no context available"
 "${SED}" -i -e "s|returns_ 1||g" tests/cp/no-ctx.sh
+
+# The rm-readdir-fail.sh test hooks readdir() but uutils rm uses nix library which calls readdir64_r().
+# readdir64_r has a different signature: int readdir64_r(DIR*, struct dirent64*, struct dirent64**)
+"${SED}" -i \
+    -e 's/struct dirent \*readdir (DIR \*dirp)/int readdir64_r(DIR *dirp, struct dirent64 *entry, struct dirent64 **result)/' \
+    -e 's/struct dirent \*(\*real_readdir)(DIR \*dirp)/int (*real_func)(DIR *, struct dirent64 *, struct dirent64 **)/' \
+    -e 's/real_readdir/real_func/g' \
+    -e 's/dlsym (RTLD_NEXT, "readdir")/dlsym(RTLD_NEXT, "readdir64_r")/' \
+    -e 's/struct dirent\* d;/int ret;/' \
+    -e 's/! (d = real_func (dirp))/(ret = real_func(dirp, entry, result)) != 0 || !*result/' \
+    -e 's/d->d_name/entry->d_name/g' \
+    -e 's/d->d_namlen/entry->d_namlen/g' \
+    -e 's/return d;/return 0;/' \
+    -e 's/return NULL;/*result = NULL; return EIO;/' \
+    tests/rm/rm-readdir-fail.sh