fix: add uclibc MIPS signal flags compatibility

MIPS uclibc defines sa_flags as unsigned int instead of int, causing type mismatches. This adds conditional compilation to use the correct type (c_uint) for MIPS uclibc while maintaining compatibility with other platforms. Fixes signal handling on old uclibc systems (0.9.x series) commonly found on embedded MIPS devices.

Author: Gerald LATKOVIC

changelog/2671.fixed.md

@@ -0,0 +1 @@
+Fixed signal handling compatibility for uclibc on MIPS platforms by using the correct type for `sa_flags`

src/sys/signal.rs

@@ -428,7 +428,11 @@ pub const SIGUNUSED : Signal = SIGSYS;
 cfg_if! {
  if #[cfg(target_os = "redox")] {
  type SaFlags_t = libc::c_ulong;
+ } else if #[cfg(all(target_env = "uclibc", target_arch = "mips"))] {
+ // MIPS uclibc uses unsigned (c_uint) for sa_flags
+ type SaFlags_t = libc::c_uint;
  } else if #[cfg(target_env = "uclibc")] {
+ // Modern uclibc-ng typically uses c_ulong
  type SaFlags_t = libc::c_ulong;
  } else {
  type SaFlags_t = libc::c_int;
@@ -437,32 +441,66 @@ cfg_if! {
 }
 
 #[cfg(feature = "signal")]
-libc_bitflags! {
- /// Controls the behavior of a [`SigAction`]
- #[cfg_attr(docsrs, doc(cfg(feature = "signal")))]
- pub struct SaFlags: SaFlags_t {
- /// When catching a [`Signal::SIGCHLD`] signal, the signal will be
- /// generated only when a child process exits, not when a child process
- /// stops.
- SA_NOCLDSTOP;
- /// When catching a [`Signal::SIGCHLD`] signal, the system will not
- /// create zombie processes when children of the calling process exit.
- #[cfg(not(target_os = "hurd"))]
- SA_NOCLDWAIT;
- /// Further occurrences of the delivered signal are not masked during
- /// the execution of the handler.
- SA_NODEFER;
- /// The system will deliver the signal to the process on a signal stack,
- /// specified by each thread with sigaltstack(2).
- SA_ONSTACK;
- /// The handler is reset back to the default at the moment the signal is
- /// delivered.
- SA_RESETHAND;
- /// Requests that certain system calls restart if interrupted by this
- /// signal. See the man page for complete details.
- SA_RESTART;
- /// This flag is controlled internally by Nix.
- SA_SIGINFO;
+cfg_if! {
+ if #[cfg(all(target_env = "uclibc", target_arch = "mips"))] {
+ // MIPS uclibc needs explicit casting from i32 to u32
+ libc_bitflags! {
+ /// Controls the behavior of a [`SigAction`]
+ #[cfg_attr(docsrs, doc(cfg(feature = "signal")))]
+ pub struct SaFlags: SaFlags_t {
+ /// When catching a [`Signal::SIGCHLD`] signal, the signal will be
+ /// generated only when a child process exits, not when a child process
+ /// stops.
+ SA_NOCLDSTOP as SaFlags_t;
+ /// When catching a [`Signal::SIGCHLD`] signal, the system will not
+ /// create zombie processes when children of the calling process exit.
+ #[cfg(not(target_os = "hurd"))]
+ SA_NOCLDWAIT as SaFlags_t;
+ /// Further occurrences of the delivered signal are not masked during
+ /// the execution of the handler.
+ SA_NODEFER as SaFlags_t;
+ /// The system will deliver the signal to the process on a signal stack,
+ /// specified by each thread with sigaltstack(2).
+ SA_ONSTACK as SaFlags_t;
+ /// The handler is reset back to the default at the moment the signal is
+ /// delivered.
+ SA_RESETHAND as SaFlags_t;
+ /// Requests that certain system calls restart if interrupted by this
+ /// signal. See the man page for complete details.
+ SA_RESTART as SaFlags_t;
+ /// This flag is controlled internally by Nix.
+ SA_SIGINFO as SaFlags_t;
+ }
+ }
+ } else {
+ libc_bitflags! {
+ /// Controls the behavior of a [`SigAction`]
+ #[cfg_attr(docsrs, doc(cfg(feature = "signal")))]
+ pub struct SaFlags: SaFlags_t {
+ /// When catching a [`Signal::SIGCHLD`] signal, the signal will be
+ /// generated only when a child process exits, not when a child process
+ /// stops.
+ SA_NOCLDSTOP;
+ /// When catching a [`Signal::SIGCHLD`] signal, the system will not
+ /// create zombie processes when children of the calling process exit.
+ #[cfg(not(target_os = "hurd"))]
+ SA_NOCLDWAIT;
+ /// Further occurrences of the delivered signal are not masked during
+ /// the execution of the handler.
+ SA_NODEFER;
+ /// The system will deliver the signal to the process on a signal stack,
+ /// specified by each thread with sigaltstack(2).
+ SA_ONSTACK;
+ /// The handler is reset back to the default at the moment the signal is
+ /// delivered.
+ SA_RESETHAND;
+ /// Requests that certain system calls restart if interrupted by this
+ /// signal. See the man page for complete details.
+ SA_RESTART;
+ /// This flag is controlled internally by Nix.
+ SA_SIGINFO;
+ }
+ }
  }
 }