android_get_control_socket uses crate::inherited_fd ... because the socket FDs are inherited. Bug: 243500154 Test: build Merged-In: I247e357fd4b66f97daf070a525005fb00a32ede3 Change-Id: I247e357fd4b66f97daf070a525005fb00a32ede3
diff --git a/sockets.rs b/sockets.rs index 0ea65fc..5edbd6c 100644 --- a/sockets.rs +++ b/sockets.rs
@@ -14,40 +14,41 @@ //! Provides utilities for sockets. -use nix::errno::Errno; -use nix::fcntl::{fcntl, FdFlag, F_SETFD}; use std::ffi::CString; -use std::os::unix::io::RawFd; +use std::os::fd::OwnedFd; use thiserror::Error; +use crate::inherited_fd; + /// Errors this crate can generate #[derive(Error, Debug)] pub enum SocketError { - /// invalid name parameter - #[error("socket name {0} contains NUL byte")] - NulError(String), + /// Invalid socket name. It could be either due to a null byte in the name, or the name refers + /// to a non-existing socket. + #[error("socket name {0} is invalid")] + InvalidName(String), - /// android_get_control_socket failed to get a fd - #[error("android_get_control_socket({0}) failed")] - GetControlSocketFailed(String), - - /// Failed to execute fcntl - #[error("Failed to execute fcntl {0}")] - FcntlFailed(Errno), + /// Error when taking ownership of the socket file descriptor. + #[error("Failed to take file descriptor ownership: {0}")] + OwnershipFailed(inherited_fd::Error), } -/// android_get_control_socket - simple helper function to get the file -/// descriptor of our init-managed Unix domain socket. `name' is the name of the -/// socket, as given in init.rc. Returns -1 on error. +/// Get `OwnedFd` for a Unix domain socket that init created under the name `name`. See +/// [Android Init Language] +/// (https://cs.android.com/android/platform/superproject/main/+/main:system/core/init/README.md) +/// for creating sockets and giving them names. +/// /// The returned file descriptor has the flag CLOEXEC set. -pub fn android_get_control_socket(name: &str) -> Result<RawFd, SocketError> { - let cstr = CString::new(name).map_err(|_| SocketError::NulError(name.to_owned()))?; +/// +/// This function returns `SocketError::OwnershipFailed` if `crate::inherited_fd::init_once` was +/// not called very early in the process startup or this function is called multile times with the +/// same `name`. +pub fn android_get_control_socket(name: &str) -> Result<OwnedFd, SocketError> { + let cstr = CString::new(name).map_err(|_| SocketError::InvalidName(name.to_owned()))?; // SAFETY: android_get_control_socket doesn't take ownership of name let fd = unsafe { cutils_bindgen::android_get_control_socket(cstr.as_ptr()) }; if fd < 0 { - return Err(SocketError::GetControlSocketFailed(name.to_owned())); + return Err(SocketError::InvalidName(name.to_owned())); } - // The file descriptor had CLOEXEC disabled to be inherited from the parent. - fcntl(fd, F_SETFD(FdFlag::FD_CLOEXEC)).map_err(SocketError::FcntlFailed)?; - Ok(fd) + inherited_fd::take_fd_ownership(fd).map_err(SocketError::OwnershipFailed) } 