Revert changes about libsafe_ownedfd

It actually was an unsafe abstraction over OwnedFd::from_raw_fd.

This change reverts following changes:

Revert "Remove the use of from_raw_fd from fd_server/aidl.rs"

This reverts commit 105153e486d7d2dfded4d0c41b22fb2bc493a5ee.

Revert "Remove yet another use of from_raw_fd"

This reverts commit abdbd756f696a1c0d0035d1a80b3d6e827c635f0.

Revert "Don't use unsafe raw_from_fd"

This reverts commit 2867dd3e838fb4deb71f335a15e0c9dc2d617240.

Revert "Remove one more use of from_raw_fd"

This reverts commit 9ef2732fb3d55ee6b085e4a02cfbb1078b041ef8.

Revert "Use take_fd_ownership instead of the unsafe from_raw_fd"

This reverts commit ba3099ec10003d6bb2c84138bbb422997142466d.

Revert "Add libsafe_ownedfd crate"

This reverts commit 1743878cd20564e42fe41e4fbaefcb964bf83e02.

Bug: 243500154
Test: N/A
Change-Id: I4e12876518a337f1f14dc1301de909b8ace28282
diff --git a/android/fd_server/Android.bp b/android/fd_server/Android.bp
index 32a8fec..b02c104 100644
--- a/android/fd_server/Android.bp
+++ b/android/fd_server/Android.bp
@@ -18,7 +18,6 @@
         "liblog_rust",
         "libnix",
         "librpcbinder_rs",
-        "libsafe_ownedfd",
     ],
     prefer_rlib: true,
     apex_available: ["com.android.virt"],
@@ -40,7 +39,6 @@
         "liblog_rust",
         "libnix",
         "librpcbinder_rs",
-        "libsafe_ownedfd",
     ],
     prefer_rlib: true,
     test_suites: ["general-tests"],
diff --git a/android/fd_server/src/aidl.rs b/android/fd_server/src/aidl.rs
index 2f3697c..5f91987 100644
--- a/android/fd_server/src/aidl.rs
+++ b/android/fd_server/src/aidl.rs
@@ -14,21 +14,20 @@
  * limitations under the License.
  */
 
-use anyhow::{Context, Result};
+use anyhow::Result;
 use log::error;
 use nix::{
     errno::Errno, fcntl::openat, fcntl::OFlag, sys::stat::fchmod, sys::stat::mkdirat,
     sys::stat::mode_t, sys::stat::Mode, sys::statvfs::statvfs, sys::statvfs::Statvfs,
     unistd::unlinkat, unistd::UnlinkatFlags,
 };
-use safe_ownedfd::take_fd_ownership;
 use std::cmp::min;
 use std::collections::{btree_map, BTreeMap};
 use std::convert::TryInto;
 use std::fs::File;
 use std::io;
 use std::os::unix::fs::FileExt;
-use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, OwnedFd};
+use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, OwnedFd};
 use std::path::{Component, Path, PathBuf, MAIN_SEPARATOR};
 use std::sync::{Arc, RwLock};
 
@@ -39,8 +38,7 @@
     get_fsverity_metadata_path, parse_fsverity_metadata, FSVerityMetadata,
 };
 use binder::{
-    BinderFeatures, ExceptionCode, Interface, IntoBinderResult, Result as BinderResult, Status,
-    StatusCode, Strong,
+    BinderFeatures, ExceptionCode, Interface, Result as BinderResult, Status, StatusCode, Strong,
 };
 
 /// Bitflags of forbidden file mode, e.g. setuid, setgid and sticky bit.
@@ -301,11 +299,9 @@
                     mode,
                 )
                 .map_err(new_errno_error)?;
-                let new_fd = take_fd_ownership(new_fd)
-                    .context("Failed to take ownership of fd for file")
-                    .or_service_specific_exception(-1)?;
-                let new_file = File::from(new_fd);
-                Ok((new_file.as_raw_fd(), FdConfig::ReadWrite(new_file)))
+                // SAFETY: new_fd is just created and not an error.
+                let new_file = unsafe { File::from_raw_fd(new_fd) };
+                Ok((new_fd, FdConfig::ReadWrite(new_file)))
             }
             _ => Err(new_errno_error(Errno::ENOTDIR)),
         })
@@ -331,10 +327,9 @@
                     Mode::empty(),
                 )
                 .map_err(new_errno_error)?;
-                let fd_owner = take_fd_ownership(new_dir_fd)
-                    .context("Failed to take ownership of the fd for directory")
-                    .or_service_specific_exception(-1)?;
-                Ok((fd_owner.as_raw_fd(), FdConfig::OutputDir(fd_owner)))
+                // SAFETY: new_dir_fd is just created and not an error.
+                let fd_owner = unsafe { OwnedFd::from_raw_fd(new_dir_fd) };
+                Ok((new_dir_fd, FdConfig::OutputDir(fd_owner)))
             }
             _ => Err(new_errno_error(Errno::ENOTDIR)),
         })
@@ -413,11 +408,9 @@
 
 fn open_readonly_at(dir_fd: BorrowedFd, path: &Path) -> nix::Result<File> {
     let new_fd = openat(Some(dir_fd.as_raw_fd()), path, OFlag::O_RDONLY, Mode::empty())?;
-    let new_fd = take_fd_ownership(new_fd).map_err(|e| match e {
-        safe_ownedfd::Error::Errno(e) => e,
-        _ => Errno::UnknownErrno,
-    })?;
-    Ok(File::from(new_fd))
+    // SAFETY: new_fd is just created successfully and not owned.
+    let new_file = unsafe { File::from_raw_fd(new_fd) };
+    Ok(new_file)
 }
 
 fn validate_and_cast_offset(offset: i64) -> Result<u64, Status> {
diff --git a/android/virtmgr/Android.bp b/android/virtmgr/Android.bp
index cbb7b38..f0b6881 100644
--- a/android/virtmgr/Android.bp
+++ b/android/virtmgr/Android.bp
@@ -54,7 +54,6 @@
         "libregex",
         "librpcbinder_rs",
         "librustutils",
-        "libsafe_ownedfd",
         "libsemver",
         "libselinux_bindgen",
         "libserde",
diff --git a/android/virtmgr/src/aidl.rs b/android/virtmgr/src/aidl.rs
index dab78c3..87fb611 100644
--- a/android/virtmgr/src/aidl.rs
+++ b/android/virtmgr/src/aidl.rs
@@ -73,7 +73,6 @@
 use nix::unistd::pipe;
 use rpcbinder::RpcServer;
 use rustutils::system_properties;
-use safe_ownedfd::take_fd_ownership;
 use semver::VersionReq;
 use serde::Deserialize;
 use std::collections::HashSet;
@@ -85,7 +84,7 @@
 use std::iter;
 use std::num::{NonZeroU16, NonZeroU32};
 use std::ops::Range;
-use std::os::unix::io::{AsRawFd, IntoRawFd};
+use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd};
 use std::os::unix::raw::pid_t;
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex, Weak, LazyLock};
@@ -1405,7 +1404,7 @@
         let stream = VsockStream::connect_with_cid_port(self.instance.cid, port)
             .context("Failed to connect")
             .or_service_specific_exception(-1)?;
-        vsock_stream_to_pfd(stream)
+        Ok(vsock_stream_to_pfd(stream))
     }
 
     fn setHostConsoleName(&self, ptsname: &str) -> binder::Result<()> {
@@ -1564,12 +1563,10 @@
 }
 
 /// Converts a `VsockStream` to a `ParcelFileDescriptor`.
-fn vsock_stream_to_pfd(stream: VsockStream) -> binder::Result<ParcelFileDescriptor> {
-    let owned_fd = take_fd_ownership(stream.into_raw_fd())
-        .context("Failed to take ownership of the vsock stream")
-        .with_log()
-        .or_service_specific_exception(-1)?;
-    Ok(ParcelFileDescriptor::new(owned_fd))
+fn vsock_stream_to_pfd(stream: VsockStream) -> ParcelFileDescriptor {
+    // SAFETY: ownership is transferred from stream to f
+    let f = unsafe { File::from_raw_fd(stream.into_raw_fd()) };
+    ParcelFileDescriptor::new(f)
 }
 
 /// Parses the platform version requirement string.
diff --git a/android/virtmgr/src/main.rs b/android/virtmgr/src/main.rs
index e4a96ac..67e7282 100644
--- a/android/virtmgr/src/main.rs
+++ b/android/virtmgr/src/main.rs
@@ -25,16 +25,16 @@
 
 use crate::aidl::{GLOBAL_SERVICE, VirtualizationService};
 use android_system_virtualizationservice::aidl::android::system::virtualizationservice::IVirtualizationService::BnVirtualizationService;
-use anyhow::{bail, Result};
+use anyhow::{bail, Context, Result};
 use binder::{BinderFeatures, ProcessState};
 use log::{info, LevelFilter};
 use rpcbinder::{FileDescriptorTransportMode, RpcServer};
-use std::os::unix::io::{AsFd, RawFd};
+use std::os::unix::io::{AsFd, FromRawFd, OwnedFd, RawFd};
 use std::sync::LazyLock;
 use clap::Parser;
+use nix::fcntl::{fcntl, F_GETFD, F_SETFD, FdFlag};
 use nix::unistd::{write, Pid, Uid};
 use std::os::unix::raw::{pid_t, uid_t};
-use safe_ownedfd::take_fd_ownership;
 
 const LOG_TAG: &str = "virtmgr";
 
@@ -71,6 +71,32 @@
     ready_fd: RawFd,
 }
 
+fn take_fd_ownership(raw_fd: RawFd, owned_fds: &mut Vec<RawFd>) -> Result<OwnedFd, anyhow::Error> {
+    // Basic check that the integer value does correspond to a file descriptor.
+    fcntl(raw_fd, F_GETFD).with_context(|| format!("Invalid file descriptor {raw_fd}"))?;
+
+    // The file descriptor had CLOEXEC disabled to be inherited from the parent.
+    // Re-enable it to make sure it is not accidentally inherited further.
+    fcntl(raw_fd, F_SETFD(FdFlag::FD_CLOEXEC))
+        .with_context(|| format!("Could not set CLOEXEC on file descriptor {raw_fd}"))?;
+
+    // Creating OwnedFd for stdio FDs is not safe.
+    if [libc::STDIN_FILENO, libc::STDOUT_FILENO, libc::STDERR_FILENO].contains(&raw_fd) {
+        bail!("File descriptor {raw_fd} is standard I/O descriptor");
+    }
+
+    // Reject RawFds that already have a corresponding OwnedFd.
+    if owned_fds.contains(&raw_fd) {
+        bail!("File descriptor {raw_fd} already owned");
+    }
+    owned_fds.push(raw_fd);
+
+    // SAFETY: Initializing OwnedFd for a RawFd provided in cmdline arguments.
+    // We checked that the integer value corresponds to a valid FD and that this
+    // is the first argument to claim its ownership.
+    Ok(unsafe { OwnedFd::from_raw_fd(raw_fd) })
+}
+
 fn check_vm_support() -> Result<()> {
     if hypervisor_props::is_any_vm_supported()? {
         Ok(())
@@ -94,9 +120,11 @@
 
     let args = Args::parse();
 
-    let rpc_server_fd =
-        take_fd_ownership(args.rpc_server_fd).expect("Failed to take ownership of rpc_server_fd");
-    let ready_fd = take_fd_ownership(args.ready_fd).expect("Failed to take ownership of ready_fd");
+    let mut owned_fds = vec![];
+    let rpc_server_fd = take_fd_ownership(args.rpc_server_fd, &mut owned_fds)
+        .expect("Failed to take ownership of rpc_server_fd");
+    let ready_fd = take_fd_ownership(args.ready_fd, &mut owned_fds)
+        .expect("Failed to take ownership of ready_fd");
 
     // Start thread pool for kernel Binder connection to VirtualizationServiceInternal.
     ProcessState::start_thread_pool();