Take ownership of inherited FDs using the rustutils crate
Ignore-AOSP-First: the topic includes git_main-only change. Will
cherry-pick the rest.
Bug: 3259955
Test: watch TH
Flag: EXEMPT refactor
Change-Id: I316a56142401b5f9bcb8ed350280019d7ddab123
diff --git a/android/fd_server/src/main.rs b/android/fd_server/src/main.rs
index 26315bf..de7ca1d 100644
--- a/android/fd_server/src/main.rs
+++ b/android/fd_server/src/main.rs
@@ -29,9 +29,10 @@
use log::debug;
use nix::sys::stat::{umask, Mode};
use rpcbinder::RpcServer;
+use rustutils::inherited_fd::take_fd_ownership;
use std::collections::BTreeMap;
use std::fs::File;
-use std::os::unix::io::{FromRawFd, OwnedFd};
+use std::os::unix::io::OwnedFd;
use aidl::{FdConfig, FdService};
use authfs_fsverity_metadata::parse_fsverity_metadata;
@@ -39,20 +40,6 @@
// TODO(b/259920193): support dynamic port for multiple fd_server instances
const RPC_SERVICE_PORT: u32 = 3264;
-fn is_fd_valid(fd: i32) -> bool {
- // SAFETY: a query-only syscall
- let retval = unsafe { libc::fcntl(fd, libc::F_GETFD) };
- retval >= 0
-}
-
-fn fd_to_owned<T: FromRawFd>(fd: i32) -> Result<T> {
- if !is_fd_valid(fd) {
- bail!("Bad FD: {}", fd);
- }
- // SAFETY: The caller is supposed to provide valid FDs to this process.
- Ok(unsafe { T::from_raw_fd(fd) })
-}
-
fn parse_arg_ro_fds(arg: &str) -> Result<(i32, FdConfig)> {
let result: Result<Vec<i32>, _> = arg.split(':').map(|x| x.parse::<i32>()).collect();
let fds = result?;
@@ -62,13 +49,13 @@
Ok((
fds[0],
FdConfig::Readonly {
- file: fd_to_owned(fds[0])?,
+ file: take_fd_ownership(fds[0])?.into(),
// Alternative metadata source, if provided
alt_metadata: fds
.get(1)
- .map(|fd| fd_to_owned(*fd))
+ .map(|fd| take_fd_ownership(*fd))
.transpose()?
- .and_then(|f| parse_fsverity_metadata(f).ok()),
+ .and_then(|f| parse_fsverity_metadata(f.into()).ok()),
},
))
}
@@ -105,23 +92,27 @@
fd_pool.insert(fd, config);
}
for fd in args.rw_fds {
- let file = fd_to_owned::<File>(fd)?;
+ let file: File = take_fd_ownership(fd)?.into();
if file.metadata()?.len() > 0 {
bail!("File is expected to be empty");
}
fd_pool.insert(fd, FdConfig::ReadWrite(file));
}
for fd in args.ro_dirs {
- fd_pool.insert(fd, FdConfig::InputDir(fd_to_owned(fd)?));
+ fd_pool.insert(fd, FdConfig::InputDir(take_fd_ownership(fd)?));
}
for fd in args.rw_dirs {
- fd_pool.insert(fd, FdConfig::OutputDir(fd_to_owned(fd)?));
+ fd_pool.insert(fd, FdConfig::OutputDir(take_fd_ownership(fd)?));
}
- let ready_fd = args.ready_fd.map(fd_to_owned).transpose()?;
+ let ready_fd = args.ready_fd.map(take_fd_ownership).transpose()?;
Ok((fd_pool, ready_fd))
}
fn main() -> Result<()> {
+ // SAFETY: This is very early in the process. Nobody has taken ownership of the inherited FDs
+ // yet.
+ unsafe { rustutils::inherited_fd::init_once()? };
+
android_logger::init_once(
android_logger::Config::default()
.with_tag("fd_server")