Adding upstream version 1.68.2+dfsg1.upstream/1.68.2+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 85 insertions, 69 deletions

diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index 37a49f2d7..8e1f35d6c 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -149,12 +149,13 @@ cfg_has_statx! {{
     ) -> Option<io::Result<FileAttr>> {
         use crate::sync::atomic::{AtomicU8, Ordering};
 
-        // Linux kernel prior to 4.11 or glibc prior to glibc 2.28 don't support `statx`
-        // We store the availability in global to avoid unnecessary syscalls.
-        // 0: Unknown
-        // 1: Not available
-        // 2: Available
-        static STATX_STATE: AtomicU8 = AtomicU8::new(0);
+        // Linux kernel prior to 4.11 or glibc prior to glibc 2.28 don't support `statx`.
+        // We check for it on first failure and remember availability to avoid having to
+        // do it again.
+        #[repr(u8)]
+        enum STATX_STATE{ Unknown = 0, Present, Unavailable }
+        static STATX_SAVED_STATE: AtomicU8 = AtomicU8::new(STATX_STATE::Unknown as u8);
+
         syscall! {
             fn statx(
                 fd: c_int,
@@ -165,31 +166,44 @@ cfg_has_statx! {{
             ) -> c_int
         }
 
-        match STATX_STATE.load(Ordering::Relaxed) {
-            0 => {
-                // It is a trick to call `statx` with null pointers to check if the syscall
-                // is available. According to the manual, it is expected to fail with EFAULT.
-                // We do this mainly for performance, since it is nearly hundreds times
-                // faster than a normal successful call.
-                let err = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
-                    .err()
-                    .and_then(|e| e.raw_os_error());
-                // We don't check `err == Some(libc::ENOSYS)` because the syscall may be limited
-                // and returns `EPERM`. Listing all possible errors seems not a good idea.
-                // See: https://github.com/rust-lang/rust/issues/65662
-                if err != Some(libc::EFAULT) {
-                    STATX_STATE.store(1, Ordering::Relaxed);
-                    return None;
-                }
-                STATX_STATE.store(2, Ordering::Relaxed);
-            }
-            1 => return None,
-            _ => {}
+        if STATX_SAVED_STATE.load(Ordering::Relaxed) == STATX_STATE::Unavailable as u8 {
+            return None;
         }
 
         let mut buf: libc::statx = mem::zeroed();
         if let Err(err) = cvt(statx(fd, path, flags, mask, &mut buf)) {
-            return Some(Err(err));
+            if STATX_SAVED_STATE.load(Ordering::Relaxed) == STATX_STATE::Present as u8 {
+                return Some(Err(err));
+            }
+
+            // Availability not checked yet.
+            //
+            // First try the cheap way.
+            if err.raw_os_error() == Some(libc::ENOSYS) {
+                STATX_SAVED_STATE.store(STATX_STATE::Unavailable as u8, Ordering::Relaxed);
+                return None;
+            }
+
+            // Error other than `ENOSYS` is not a good enough indicator -- it is
+            // known that `EPERM` can be returned as a result of using seccomp to
+            // block the syscall.
+            // Availability is checked by performing a call which expects `EFAULT`
+            // if the syscall is usable.
+            // See: https://github.com/rust-lang/rust/issues/65662
+            // FIXME this can probably just do the call if `EPERM` was received, but
+            // previous iteration of the code checked it for all errors and for now
+            // this is retained.
+            // FIXME what about transient conditions like `ENOMEM`?
+            let err2 = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
+                .err()
+                .and_then(|e| e.raw_os_error());
+            if err2 == Some(libc::EFAULT) {
+                STATX_SAVED_STATE.store(STATX_STATE::Present as u8, Ordering::Relaxed);
+                return Some(Err(err));
+            } else {
+                STATX_SAVED_STATE.store(STATX_STATE::Unavailable as u8, Ordering::Relaxed);
+                return None;
+            }
         }
 
         // We cannot fill `stat64` exhaustively because of private padding fields.
@@ -243,17 +257,15 @@ struct InnerReadDir {
 
 pub struct ReadDir {
     inner: Arc<InnerReadDir>,
-    #[cfg(not(any(
-        target_os = "android",
-        target_os = "linux",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "fuchsia",
-        target_os = "redox",
-    )))]
     end_of_stream: bool,
 }
 
+impl ReadDir {
+    fn new(inner: InnerReadDir) -> Self {
+        Self { inner: Arc::new(inner), end_of_stream: false }
+    }
+}
+
 struct Dir(*mut libc::DIR);
 
 unsafe impl Send for Dir {}
@@ -332,11 +344,23 @@ pub struct FileTimes {
     modified: Option<SystemTime>,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, Eq, Debug)]
 pub struct FileType {
     mode: mode_t,
 }
 
+impl PartialEq for FileType {
+    fn eq(&self, other: &Self) -> bool {
+        self.masked() == other.masked()
+    }
+}
+
+impl core::hash::Hash for FileType {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        self.masked().hash(state);
+    }
+}
+
 #[derive(Debug)]
 pub struct DirBuilder {
     mode: mode_t,
@@ -548,7 +572,11 @@ impl FileType {
     }
 
     pub fn is(&self, mode: mode_t) -> bool {
-        self.mode & libc::S_IFMT == mode
+        self.masked() == mode
+    }
+
+    fn masked(&self) -> mode_t {
+        self.mode & libc::S_IFMT
     }
 }
 
@@ -578,18 +606,26 @@ impl Iterator for ReadDir {
         target_os = "illumos"
     ))]
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
+        if self.end_of_stream {
+            return None;
+        }
+
         unsafe {
             loop {
                 // As of POSIX.1-2017, readdir() is not required to be thread safe; only
                 // readdir_r() is. However, readdir_r() cannot correctly handle platforms
-                // with unlimited or variable NAME_MAX.  Many modern platforms guarantee
+                // with unlimited or variable NAME_MAX. Many modern platforms guarantee
                 // thread safety for readdir() as long an individual DIR* is not accessed
                 // concurrently, which is sufficient for Rust.
                 super::os::set_errno(0);
                 let entry_ptr = readdir64(self.inner.dirp.0);
                 if entry_ptr.is_null() {
-                    // null can mean either the end is reached or an error occurred.
-                    // So we had to clear errno beforehand to check for an error now.
+                    // We either encountered an error, or reached the end. Either way,
+                    // the next call to next() should return None.
+                    self.end_of_stream = true;
+
+                    // To distinguish between errors and end-of-directory, we had to clear
+                    // errno beforehand to check for an error now.
                     return match super::os::errno() {
                         0 => None,
                         e => Some(Err(Error::from_raw_os_error(e))),
@@ -1347,18 +1383,7 @@ pub fn readdir(path: &Path) -> io::Result<ReadDir> {
     } else {
         let root = path.to_path_buf();
         let inner = InnerReadDir { dirp: Dir(ptr), root };
-        Ok(ReadDir {
-            inner: Arc::new(inner),
-            #[cfg(not(any(
-                target_os = "android",
-                target_os = "linux",
-                target_os = "solaris",
-                target_os = "illumos",
-                target_os = "fuchsia",
-                target_os = "redox",
-            )))]
-            end_of_stream: false,
-        })
+        Ok(ReadDir::new(inner))
     }
 }
 
@@ -1739,12 +1764,16 @@ mod remove_dir_impl {
     use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
     use crate::os::unix::prelude::{OwnedFd, RawFd};
     use crate::path::{Path, PathBuf};
-    use crate::sync::Arc;
     use crate::sys::common::small_c_string::run_path_with_cstr;
     use crate::sys::{cvt, cvt_r};
 
-    #[cfg(not(all(target_os = "macos", not(target_arch = "aarch64")),))]
+    #[cfg(not(any(
+        all(target_os = "linux", target_env = "gnu"),
+        all(target_os = "macos", not(target_arch = "aarch64"))
+    )))]
     use libc::{fdopendir, openat, unlinkat};
+    #[cfg(all(target_os = "linux", target_env = "gnu"))]
+    use libc::{fdopendir, openat64 as openat, unlinkat};
     #[cfg(all(target_os = "macos", not(target_arch = "aarch64")))]
     use macos_weak::{fdopendir, openat, unlinkat};
 
@@ -1811,21 +1840,8 @@ mod remove_dir_impl {
         // a valid root is not needed because we do not call any functions involving the full path
         // of the DirEntrys.
         let dummy_root = PathBuf::new();
-        Ok((
-            ReadDir {
-                inner: Arc::new(InnerReadDir { dirp, root: dummy_root }),
-                #[cfg(not(any(
-                    target_os = "android",
-                    target_os = "linux",
-                    target_os = "solaris",
-                    target_os = "illumos",
-                    target_os = "fuchsia",
-                    target_os = "redox",
-                )))]
-                end_of_stream: false,
-            },
-            new_parent_fd,
-        ))
+        let inner = InnerReadDir { dirp, root: dummy_root };
+        Ok((ReadDir::new(inner), new_parent_fd))
     }
 
     #[cfg(any(