Mark most C-derived enums as non_exhaustive

Since libc may add new variants at any time, Nix's consumers should not
use exhaustive match patterns.

Fixes #1182

Author: asomers

CHANGELOG.md

@@ -14,6 +14,10 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - `FdSet::{contains, highest, fds}` no longer require a mutable reference.
   (#[1464](https://github.com/nix-rust/nix/pull/1464))
 
+- Most enums that come from C, for example `Errno`, are now marked as
+  `#[non_exhaustive]`.
+  (#[1474](https://github.com/nix-rust/nix/pull/1474))
+
 ### Fixed
 
 - Added more errno definitions for better backwards compatibility with

src/errno.rs

@@ -768,6 +768,7 @@ fn desc(errno: Errno) -> &'static str {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -1073,6 +1074,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -1324,6 +1326,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -1562,6 +1565,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -1796,6 +1800,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -2019,6 +2024,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno    = 0,
         EPERM           = libc::EPERM,
@@ -2244,6 +2250,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno = 0,
         EPERM = libc::EPERM,
@@ -2441,6 +2448,7 @@ mod consts {
 mod consts {
     #[derive(Clone, Copy, Debug, Eq, PartialEq)]
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum Errno {
         UnknownErrno = 0,
         EPERM = libc::EPERM,

src/fcntl.rs

@@ -374,6 +374,7 @@ libc_bitflags!(
 
 #[cfg(not(target_os = "redox"))]
 #[derive(Debug, Eq, Hash, PartialEq)]
+#[non_exhaustive]
 pub enum FcntlArg<'a> {
     F_DUPFD(RawFd),
     F_DUPFD_CLOEXEC(RawFd),
@@ -405,6 +406,7 @@ pub enum FcntlArg<'a> {
 
 #[cfg(target_os = "redox")]
 #[derive(Debug, Clone, Copy, Eq, Hash, PartialEq)]
+#[non_exhaustive]
 pub enum FcntlArg {
     F_DUPFD(RawFd),
     F_DUPFD_CLOEXEC(RawFd),
@@ -454,6 +456,7 @@ pub fn fcntl(fd: RawFd, arg: FcntlArg) -> Result<c_int> {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[non_exhaustive]
 pub enum FlockArg {
     LockShared,
     LockExclusive,
@@ -649,6 +652,7 @@ mod posix_fadvise {
 
     libc_enum! {
         #[repr(i32)]
+        #[non_exhaustive]
         pub enum PosixFadviseAdvice {
             POSIX_FADV_NORMAL,
             POSIX_FADV_SEQUENTIAL,

src/sys/aio.rs

@@ -39,6 +39,7 @@ libc_enum! {
     /// Mode for `AioCb::fsync`.  Controls whether only data or both data and
     /// metadata are synced.
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum AioFsyncMode {
         /// do it like `fsync`
         O_SYNC,
@@ -57,6 +58,7 @@ libc_enum! {
     /// given `aiocb` should be used for a read operation, a write operation, or
     /// ignored.  Has no effect for any other aio functions.
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum LioOpcode {
         LIO_NOP,
         LIO_WRITE,

src/sys/epoll.rs

@@ -29,6 +29,7 @@ libc_bitflags!(
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 #[repr(i32)]
+#[non_exhaustive]
 pub enum EpollOp {
     EpollCtlAdd = libc::EPOLL_CTL_ADD,
     EpollCtlDel = libc::EPOLL_CTL_DEL,

src/sys/event.rs

@@ -36,6 +36,7 @@ type type_of_event_filter = i16;
 libc_enum! {
     #[cfg_attr(target_os = "netbsd", repr(u32))]
     #[cfg_attr(not(target_os = "netbsd"), repr(i16))]
+    #[non_exhaustive]
     pub enum EventFilter {
         EVFILT_AIO,
         /// Returns whenever there is no remaining data in the write buffer

src/sys/mman.rs

@@ -155,6 +155,7 @@ libc_enum!{
     ///
     /// Used by [`madvise`](./fn.madvise.html).
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum MmapAdvise {
         /// No further special treatment. This is the default.
         MADV_NORMAL,

src/sys/ptrace/bsd.rs

@@ -24,6 +24,7 @@ cfg_if! {
 libc_enum! {
     #[repr(i32)]
     /// Ptrace Request enum defining the action to be taken.
+    #[non_exhaustive]
     pub enum Request {
         PT_TRACE_ME,
         PT_READ_I,

src/sys/ptrace/linux.rs

@@ -33,6 +33,7 @@ libc_enum!{
     #[cfg_attr(not(any(target_env = "musl", target_os = "android")), repr(u32))]
     #[cfg_attr(any(target_env = "musl", target_os = "android"), repr(i32))]
     /// Ptrace Request enum defining the action to be taken.
+    #[non_exhaustive]
     pub enum Request {
         PTRACE_TRACEME,
         PTRACE_PEEKTEXT,
@@ -123,6 +124,7 @@ libc_enum!{
     /// Using the ptrace options the tracer can configure the tracee to stop
     /// at certain events. This enum is used to define those events as defined
     /// in `man ptrace`.
+    #[non_exhaustive]
     pub enum Event {
         /// Event that stops before a return from fork or clone.
         PTRACE_EVENT_FORK,

src/sys/quota.rs

@@ -42,6 +42,7 @@ libc_enum!{
 libc_enum!{
     /// The scope of the quota.
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum QuotaType {
         /// Specify a user quota
         USRQUOTA,
@@ -53,6 +54,7 @@ libc_enum!{
 libc_enum!{
     /// The type of quota format to use.
     #[repr(i32)]
+    #[non_exhaustive]
     pub enum QuotaFmt {
         /// Use the original quota format.
         QFMT_VFS_OLD,