// Portions of this file are Copyright 2014 The Rust Project Developers. // See https://www.rust-lang.org/policies/licenses. //! Operating system signals. use crate::{Error, Result}; use crate::errno::Errno; use std::mem; use std::fmt; use std::str::FromStr; #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] use std::os::unix::io::RawFd; use std::ptr; use cfg_if::cfg_if; #[cfg(not(any(target_os = "openbsd", target_os = "redox")))] #[cfg(any(feature = "aio", feature = "signal"))] pub use self::sigevent::*; #[cfg(any(feature = "aio", feature = "process", feature = "signal"))] libc_enum!{ /// Types of operating system signals // Currently there is only one definition of c_int in libc, as well as only one // type for signal constants. // We would prefer to use the libc::c_int alias in the repr attribute. Unfortunately // this is not (yet) possible. #[repr(i32)] #[non_exhaustive] #[cfg_attr(docsrs, doc(cfg(any(feature = "aio", feature = "signal"))))] pub enum Signal { /// Hangup SIGHUP, /// Interrupt SIGINT, /// Quit SIGQUIT, /// Illegal instruction (not reset when caught) SIGILL, /// Trace trap (not reset when caught) SIGTRAP, /// Abort SIGABRT, /// Bus error SIGBUS, /// Floating point exception SIGFPE, /// Kill (cannot be caught or ignored) SIGKILL, /// User defined signal 1 SIGUSR1, /// Segmentation violation SIGSEGV, /// User defined signal 2 SIGUSR2, /// Write on a pipe with no one to read it SIGPIPE, /// Alarm clock SIGALRM, /// Software termination signal from kill SIGTERM, /// Stack fault (obsolete) #[cfg(all(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"), not(any(target_arch = "mips", target_arch = "mips64", target_arch = "sparc64"))))] SIGSTKFLT, /// To parent on child stop or exit SIGCHLD, /// Continue a stopped process SIGCONT, /// Sendable stop signal not from tty SIGSTOP, /// Stop signal from tty SIGTSTP, /// To readers pgrp upon background tty read SIGTTIN, /// Like TTIN if (tp->t_local<OSTOP) SIGTTOU, /// Urgent condition on IO channel SIGURG, /// Exceeded CPU time limit SIGXCPU, /// Exceeded file size limit SIGXFSZ, /// Virtual time alarm SIGVTALRM, /// Profiling time alarm SIGPROF, /// Window size changes SIGWINCH, /// Input/output possible signal SIGIO, #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"))] #[cfg_attr(docsrs, doc(cfg(all())))] /// Power failure imminent. SIGPWR, /// Bad system call SIGSYS, #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] #[cfg_attr(docsrs, doc(cfg(all())))] /// Emulator trap SIGEMT, #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] #[cfg_attr(docsrs, doc(cfg(all())))] /// Information request SIGINFO, } impl TryFrom } #[cfg(feature = "signal")] impl FromStr for Signal { type Err = Error; fn from_str(s: &str) -> Result { Ok(match s { "SIGHUP" => Signal::SIGHUP, "SIGINT" => Signal::SIGINT, "SIGQUIT" => Signal::SIGQUIT, "SIGILL" => Signal::SIGILL, "SIGTRAP" => Signal::SIGTRAP, "SIGABRT" => Signal::SIGABRT, "SIGBUS" => Signal::SIGBUS, "SIGFPE" => Signal::SIGFPE, "SIGKILL" => Signal::SIGKILL, "SIGUSR1" => Signal::SIGUSR1, "SIGSEGV" => Signal::SIGSEGV, "SIGUSR2" => Signal::SIGUSR2, "SIGPIPE" => Signal::SIGPIPE, "SIGALRM" => Signal::SIGALRM, "SIGTERM" => Signal::SIGTERM, #[cfg(all(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"), not(any(target_arch = "mips", target_arch = "mips64", target_arch = "sparc64"))))] "SIGSTKFLT" => Signal::SIGSTKFLT, "SIGCHLD" => Signal::SIGCHLD, "SIGCONT" => Signal::SIGCONT, "SIGSTOP" => Signal::SIGSTOP, "SIGTSTP" => Signal::SIGTSTP, "SIGTTIN" => Signal::SIGTTIN, "SIGTTOU" => Signal::SIGTTOU, "SIGURG" => Signal::SIGURG, "SIGXCPU" => Signal::SIGXCPU, "SIGXFSZ" => Signal::SIGXFSZ, "SIGVTALRM" => Signal::SIGVTALRM, "SIGPROF" => Signal::SIGPROF, "SIGWINCH" => Signal::SIGWINCH, "SIGIO" => Signal::SIGIO, #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"))] "SIGPWR" => Signal::SIGPWR, "SIGSYS" => Signal::SIGSYS, #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] "SIGEMT" => Signal::SIGEMT, #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] "SIGINFO" => Signal::SIGINFO, _ => return Err(Errno::EINVAL), }) } } #[cfg(feature = "signal")] impl Signal { /// Returns name of signal. /// /// This function is equivalent to `>::as_ref()`, /// with difference that returned string is `'static` /// and not bound to `self`'s lifetime. pub const fn as_str(self) -> &'static str { match self { Signal::SIGHUP => "SIGHUP", Signal::SIGINT => "SIGINT", Signal::SIGQUIT => "SIGQUIT", Signal::SIGILL => "SIGILL", Signal::SIGTRAP => "SIGTRAP", Signal::SIGABRT => "SIGABRT", Signal::SIGBUS => "SIGBUS", Signal::SIGFPE => "SIGFPE", Signal::SIGKILL => "SIGKILL", Signal::SIGUSR1 => "SIGUSR1", Signal::SIGSEGV => "SIGSEGV", Signal::SIGUSR2 => "SIGUSR2", Signal::SIGPIPE => "SIGPIPE", Signal::SIGALRM => "SIGALRM", Signal::SIGTERM => "SIGTERM", #[cfg(all(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"), not(any(target_arch = "mips", target_arch = "mips64", target_arch = "sparc64"))))] Signal::SIGSTKFLT => "SIGSTKFLT", Signal::SIGCHLD => "SIGCHLD", Signal::SIGCONT => "SIGCONT", Signal::SIGSTOP => "SIGSTOP", Signal::SIGTSTP => "SIGTSTP", Signal::SIGTTIN => "SIGTTIN", Signal::SIGTTOU => "SIGTTOU", Signal::SIGURG => "SIGURG", Signal::SIGXCPU => "SIGXCPU", Signal::SIGXFSZ => "SIGXFSZ", Signal::SIGVTALRM => "SIGVTALRM", Signal::SIGPROF => "SIGPROF", Signal::SIGWINCH => "SIGWINCH", Signal::SIGIO => "SIGIO", #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"))] Signal::SIGPWR => "SIGPWR", Signal::SIGSYS => "SIGSYS", #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] Signal::SIGEMT => "SIGEMT", #[cfg(not(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux", target_os = "redox")))] Signal::SIGINFO => "SIGINFO", } } } #[cfg(feature = "signal")] impl AsRef for Signal { fn as_ref(&self) -> &str { self.as_str() } } #[cfg(feature = "signal")] impl fmt::Display for Signal { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { f.write_str(self.as_ref()) } } #[cfg(feature = "signal")] pub use self::Signal::*; #[cfg(target_os = "redox")] #[cfg(feature = "signal")] const SIGNALS: [Signal; 29] = [ SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGSYS]; #[cfg(all(any(target_os = "linux", target_os = "android", target_os = "emscripten", target_os = "fuchsia"), not(any(target_arch = "mips", target_arch = "mips64", target_arch = "sparc64"))))] #[cfg(feature = "signal")] const SIGNALS: [Signal; 31] = [ SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, SIGSTKFLT, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGPWR, SIGSYS]; #[cfg(all(any(target_os = "linux", target_os = "android", target_os = "emscripten", target_os = "fuchsia"), any(target_arch = "mips", target_arch = "mips64", target_arch = "sparc64")))] #[cfg(feature = "signal")] const SIGNALS: [Signal; 30] = [ SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGPWR, SIGSYS]; #[cfg(not(any(target_os = "linux", target_os = "android", target_os = "fuchsia", target_os = "emscripten", target_os = "redox")))] #[cfg(feature = "signal")] const SIGNALS: [Signal; 31] = [ SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGSYS, SIGEMT, SIGINFO]; feature! { #![feature = "signal"] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] /// Iterate through all signals defined by this operating system pub struct SignalIterator { next: usize, } impl Iterator for SignalIterator { type Item = Signal; fn next(&mut self) -> Option { if self.next < SIGNALS.len() { let next_signal = SIGNALS[self.next]; self.next += 1; Some(next_signal) } else { None } } } impl Signal { /// Iterate through all signals defined by this OS pub const fn iterator() -> SignalIterator { SignalIterator{next: 0} } } /// Alias for [`SIGABRT`] pub const SIGIOT : Signal = SIGABRT; /// Alias for [`SIGIO`] pub const SIGPOLL : Signal = SIGIO; /// Alias for [`SIGSYS`] pub const SIGUNUSED : Signal = SIGSYS; cfg_if! { if #[cfg(target_os = "redox")] { type SaFlags_t = libc::c_ulong; } else if #[cfg(target_env = "uclibc")] { type SaFlags_t = libc::c_ulong; } else { type SaFlags_t = libc::c_int; } } } #[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. 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(feature = "signal")] libc_enum! { /// Specifies how certain functions should manipulate a signal mask #[repr(i32)] #[non_exhaustive] #[cfg_attr(docsrs, doc(cfg(feature = "signal")))] pub enum SigmaskHow { /// The new mask is the union of the current mask and the specified set. SIG_BLOCK, /// The new mask is the intersection of the current mask and the /// complement of the specified set. SIG_UNBLOCK, /// The current mask is replaced by the specified set. SIG_SETMASK, } } feature! { #![feature = "signal"] use crate::unistd::Pid; use std::iter::Extend; use std::iter::FromIterator; use std::iter::IntoIterator; /// Specifies a set of [`Signal`]s that may be blocked, waited for, etc. #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub struct SigSet { sigset: libc::sigset_t } impl SigSet { /// Initialize to include all signals. pub fn all() -> SigSet { let mut sigset = mem::MaybeUninit::uninit(); let _ = unsafe { libc::sigfillset(sigset.as_mut_ptr()) }; unsafe{ SigSet { sigset: sigset.assume_init() } } } /// Initialize to include nothing. pub fn empty() -> SigSet { let mut sigset = mem::MaybeUninit::uninit(); let _ = unsafe { libc::sigemptyset(sigset.as_mut_ptr()) }; unsafe{ SigSet { sigset: sigset.assume_init() } } } /// Add the specified signal to the set. pub fn add(&mut self, signal: Signal) { unsafe { libc::sigaddset(&mut self.sigset as *mut libc::sigset_t, signal as libc::c_int) }; } /// Remove all signals from this set. pub fn clear(&mut self) { unsafe { libc::sigemptyset(&mut self.sigset as *mut libc::sigset_t) }; } /// Remove the specified signal from this set. pub fn remove(&mut self, signal: Signal) { unsafe { libc::sigdelset(&mut self.sigset as *mut libc::sigset_t, signal as libc::c_int) }; } /// Return whether this set includes the specified signal. pub fn contains(&self, signal: Signal) -> bool { let res = unsafe { libc::sigismember(&self.sigset as *const libc::sigset_t, signal as libc::c_int) }; match res { 1 => true, 0 => false, _ => unreachable!("unexpected value from sigismember"), } } /// Returns an iterator that yields the signals contained in this set. pub fn iter(&self) -> SigSetIter<'_> { self.into_iter() } /// Gets the currently blocked (masked) set of signals for the calling thread. pub fn thread_get_mask() -> Result { let mut oldmask = mem::MaybeUninit::uninit(); do_pthread_sigmask(SigmaskHow::SIG_SETMASK, None, Some(oldmask.as_mut_ptr()))?; Ok(unsafe{ SigSet{sigset: oldmask.assume_init()}}) } /// Sets the set of signals as the signal mask for the calling thread. pub fn thread_set_mask(&self) -> Result<()> { pthread_sigmask(SigmaskHow::SIG_SETMASK, Some(self), None) } /// Adds the set of signals to the signal mask for the calling thread. pub fn thread_block(&self) -> Result<()> { pthread_sigmask(SigmaskHow::SIG_BLOCK, Some(self), None) } /// Removes the set of signals from the signal mask for the calling thread. pub fn thread_unblock(&self) -> Result<()> { pthread_sigmask(SigmaskHow::SIG_UNBLOCK, Some(self), None) } /// Sets the set of signals as the signal mask, and returns the old mask. pub fn thread_swap_mask(&self, how: SigmaskHow) -> Result { let mut oldmask = mem::MaybeUninit::uninit(); do_pthread_sigmask(how, Some(self), Some(oldmask.as_mut_ptr()))?; Ok(unsafe{ SigSet{sigset: oldmask.assume_init()}}) } /// Suspends execution of the calling thread until one of the signals in the /// signal mask becomes pending, and returns the accepted signal. #[cfg(not(target_os = "redox"))] // RedoxFS does not yet support sigwait #[cfg_attr(docsrs, doc(cfg(all())))] pub fn wait(&self) -> Result { use std::convert::TryFrom; let mut signum = mem::MaybeUninit::uninit(); let res = unsafe { libc::sigwait(&self.sigset as *const libc::sigset_t, signum.as_mut_ptr()) }; Errno::result(res).map(|_| unsafe { Signal::try_from(signum.assume_init()).unwrap() }) } } impl AsRef for SigSet { fn as_ref(&self) -> &libc::sigset_t { &self.sigset } } // TODO: Consider specialization for the case where T is &SigSet and libc::sigorset is available. impl Extend for SigSet { fn extend(&mut self, iter: T) where T: IntoIterator { for signal in iter { self.add(signal); } } } impl FromIterator for SigSet { fn from_iter(iter: T) -> Self where T: IntoIterator { let mut sigset = SigSet::empty(); sigset.extend(iter); sigset } } /// Iterator for a [`SigSet`]. /// /// Call [`SigSet::iter`] to create an iterator. #[derive(Clone, Debug)] pub struct SigSetIter<'a> { sigset: &'a SigSet, inner: SignalIterator, } impl Iterator for SigSetIter<'_> { type Item = Signal; fn next(&mut self) -> Option { loop { match self.inner.next() { None => return None, Some(signal) if self.sigset.contains(signal) => return Some(signal), Some(_signal) => continue, } } } } impl<'a> IntoIterator for &'a SigSet { type Item = Signal; type IntoIter = SigSetIter<'a>; fn into_iter(self) -> Self::IntoIter { SigSetIter { sigset: self, inner: Signal::iterator() } } } /// A signal handler. #[allow(unknown_lints)] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub enum SigHandler { /// Default signal handling. SigDfl, /// Request that the signal be ignored. SigIgn, /// Use the given signal-catching function, which takes in the signal. Handler(extern fn(libc::c_int)), /// Use the given signal-catching function, which takes in the signal, information about how /// the signal was generated, and a pointer to the threads `ucontext_t`. #[cfg(not(target_os = "redox"))] #[cfg_attr(docsrs, doc(cfg(all())))] SigAction(extern fn(libc::c_int, *mut libc::siginfo_t, *mut libc::c_void)) } /// Action to take on receipt of a signal. Corresponds to `sigaction`. #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub struct SigAction { sigaction: libc::sigaction } impl SigAction { /// Creates a new action. /// /// The `SA_SIGINFO` bit in the `flags` argument is ignored (it will be set only if `handler` /// is the `SigAction` variant). `mask` specifies other signals to block during execution of /// the signal-catching function. pub fn new(handler: SigHandler, flags: SaFlags, mask: SigSet) -> SigAction { #[cfg(target_os = "redox")] unsafe fn install_sig(p: *mut libc::sigaction, handler: SigHandler) { (*p).sa_handler = match handler { SigHandler::SigDfl => libc::SIG_DFL, SigHandler::SigIgn => libc::SIG_IGN, SigHandler::Handler(f) => f as *const extern fn(libc::c_int) as usize, }; } #[cfg(not(target_os = "redox"))] unsafe fn install_sig(p: *mut libc::sigaction, handler: SigHandler) { (*p).sa_sigaction = match handler { SigHandler::SigDfl => libc::SIG_DFL, SigHandler::SigIgn => libc::SIG_IGN, SigHandler::Handler(f) => f as *const extern fn(libc::c_int) as usize, SigHandler::SigAction(f) => f as *const extern fn(libc::c_int, *mut libc::siginfo_t, *mut libc::c_void) as usize, }; } let mut s = mem::MaybeUninit::::uninit(); unsafe { let p = s.as_mut_ptr(); install_sig(p, handler); (*p).sa_flags = match handler { #[cfg(not(target_os = "redox"))] SigHandler::SigAction(_) => (flags | SaFlags::SA_SIGINFO).bits(), _ => (flags - SaFlags::SA_SIGINFO).bits(), }; (*p).sa_mask = mask.sigset; SigAction { sigaction: s.assume_init() } } } /// Returns the flags set on the action. pub fn flags(&self) -> SaFlags { SaFlags::from_bits_truncate(self.sigaction.sa_flags) } /// Returns the set of signals that are blocked during execution of the action's /// signal-catching function. pub fn mask(&self) -> SigSet { SigSet { sigset: self.sigaction.sa_mask } } /// Returns the action's handler. #[cfg(not(target_os = "redox"))] #[cfg_attr(docsrs, doc(cfg(all())))] pub fn handler(&self) -> SigHandler { match self.sigaction.sa_sigaction { libc::SIG_DFL => SigHandler::SigDfl, libc::SIG_IGN => SigHandler::SigIgn, p if self.flags().contains(SaFlags::SA_SIGINFO) => SigHandler::SigAction( // Safe for one of two reasons: // * The SigHandler was created by SigHandler::new, in which // case the pointer is correct, or // * The SigHandler was created by signal or sigaction, which // are unsafe functions, so the caller should've somehow // ensured that it is correctly initialized. unsafe{ *(&p as *const usize as *const extern fn(_, _, _)) } as extern fn(_, _, _)), p => SigHandler::Handler( // Safe for one of two reasons: // * The SigHandler was created by SigHandler::new, in which // case the pointer is correct, or // * The SigHandler was created by signal or sigaction, which // are unsafe functions, so the caller should've somehow // ensured that it is correctly initialized. unsafe{ *(&p as *const usize as *const extern fn(libc::c_int)) } as extern fn(libc::c_int)), } } /// Returns the action's handler. #[cfg(target_os = "redox")] #[cfg_attr(docsrs, doc(cfg(all())))] pub fn handler(&self) -> SigHandler { match self.sigaction.sa_handler { libc::SIG_DFL => SigHandler::SigDfl, libc::SIG_IGN => SigHandler::SigIgn, p => SigHandler::Handler( // Safe for one of two reasons: // * The SigHandler was created by SigHandler::new, in which // case the pointer is correct, or // * The SigHandler was created by signal or sigaction, which // are unsafe functions, so the caller should've somehow // ensured that it is correctly initialized. unsafe{ *(&p as *const usize as *const extern fn(libc::c_int)) } as extern fn(libc::c_int)), } } } /// Changes the action taken by a process on receipt of a specific signal. /// /// `signal` can be any signal except `SIGKILL` or `SIGSTOP`. On success, it returns the previous /// action for the given signal. If `sigaction` fails, no new signal handler is installed. /// /// # Safety /// /// * Signal handlers may be called at any point during execution, which limits /// what is safe to do in the body of the signal-catching function. Be certain /// to only make syscalls that are explicitly marked safe for signal handlers /// and only share global data using atomics. /// /// * There is also no guarantee that the old signal handler was installed /// correctly. If it was installed by this crate, it will be. But if it was /// installed by, for example, C code, then there is no guarantee its function /// pointer is valid. In that case, this function effectively dereferences a /// raw pointer of unknown provenance. pub unsafe fn sigaction(signal: Signal, sigaction: &SigAction) -> Result { let mut oldact = mem::MaybeUninit::::uninit(); let res = libc::sigaction(signal as libc::c_int, &sigaction.sigaction as *const libc::sigaction, oldact.as_mut_ptr()); Errno::result(res).map(|_| SigAction { sigaction: oldact.assume_init() }) } /// Signal management (see [signal(3p)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/signal.html)) /// /// Installs `handler` for the given `signal`, returning the previous signal /// handler. `signal` should only be used following another call to `signal` or /// if the current handler is the default. The return value of `signal` is /// undefined after setting the handler with [`sigaction`][SigActionFn]. /// /// # Safety /// /// If the pointer to the previous signal handler is invalid, undefined /// behavior could be invoked when casting it back to a [`SigAction`][SigActionStruct]. /// /// # Examples /// /// Ignore `SIGINT`: /// /// ```no_run /// # use nix::sys::signal::{self, Signal, SigHandler}; /// unsafe { signal::signal(Signal::SIGINT, SigHandler::SigIgn) }.unwrap(); /// ``` /// /// Use a signal handler to set a flag variable: /// /// ```no_run /// # #[macro_use] extern crate lazy_static; /// # use std::convert::TryFrom; /// # use std::sync::atomic::{AtomicBool, Ordering}; /// # use nix::sys::signal::{self, Signal, SigHandler}; /// lazy_static! { /// static ref SIGNALED: AtomicBool = AtomicBool::new(false); /// } /// /// extern fn handle_sigint(signal: libc::c_int) { /// let signal = Signal::try_from(signal).unwrap(); /// SIGNALED.store(signal == Signal::SIGINT, Ordering::Relaxed); /// } /// /// fn main() { /// let handler = SigHandler::Handler(handle_sigint); /// unsafe { signal::signal(Signal::SIGINT, handler) }.unwrap(); /// } /// ``` /// /// # Errors /// /// Returns [`Error(Errno::EOPNOTSUPP)`] if `handler` is /// [`SigAction`][SigActionStruct]. Use [`sigaction`][SigActionFn] instead. /// /// `signal` also returns any error from `libc::signal`, such as when an attempt /// is made to catch a signal that cannot be caught or to ignore a signal that /// cannot be ignored. /// /// [`Error::UnsupportedOperation`]: ../../enum.Error.html#variant.UnsupportedOperation /// [SigActionStruct]: struct.SigAction.html /// [sigactionFn]: fn.sigaction.html pub unsafe fn signal(signal: Signal, handler: SigHandler) -> Result { let signal = signal as libc::c_int; let res = match handler { SigHandler::SigDfl => libc::signal(signal, libc::SIG_DFL), SigHandler::SigIgn => libc::signal(signal, libc::SIG_IGN), SigHandler::Handler(handler) => libc::signal(signal, handler as libc::sighandler_t), #[cfg(not(target_os = "redox"))] SigHandler::SigAction(_) => return Err(Errno::ENOTSUP), }; Errno::result(res).map(|oldhandler| { match oldhandler { libc::SIG_DFL => SigHandler::SigDfl, libc::SIG_IGN => SigHandler::SigIgn, p => SigHandler::Handler( *(&p as *const usize as *const extern fn(libc::c_int)) as extern fn(libc::c_int)), } }) } fn do_pthread_sigmask(how: SigmaskHow, set: Option<&SigSet>, oldset: Option<*mut libc::sigset_t>) -> Result<()> { if set.is_none() && oldset.is_none() { return Ok(()) } let res = unsafe { // if set or oldset is None, pass in null pointers instead libc::pthread_sigmask(how as libc::c_int, set.map_or_else(ptr::null::, |s| &s.sigset as *const libc::sigset_t), oldset.unwrap_or(ptr::null_mut()) ) }; Errno::result(res).map(drop) } /// Manages the signal mask (set of blocked signals) for the calling thread. /// /// If the `set` parameter is `Some(..)`, then the signal mask will be updated with the signal set. /// The `how` flag decides the type of update. If `set` is `None`, `how` will be ignored, /// and no modification will take place. /// /// If the 'oldset' parameter is `Some(..)` then the current signal mask will be written into it. /// /// If both `set` and `oldset` is `Some(..)`, the current signal mask will be written into oldset, /// and then it will be updated with `set`. /// /// If both `set` and `oldset` is None, this function is a no-op. /// /// For more information, visit the [`pthread_sigmask`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_sigmask.html), /// or [`sigprocmask`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigprocmask.html) man pages. pub fn pthread_sigmask(how: SigmaskHow, set: Option<&SigSet>, oldset: Option<&mut SigSet>) -> Result<()> { do_pthread_sigmask(how, set, oldset.map(|os| &mut os.sigset as *mut _ )) } /// Examine and change blocked signals. /// /// For more information see the [`sigprocmask` man /// pages](https://pubs.opengroup.org/onlinepubs/9699919799/functions/sigprocmask.html). pub fn sigprocmask(how: SigmaskHow, set: Option<&SigSet>, oldset: Option<&mut SigSet>) -> Result<()> { if set.is_none() && oldset.is_none() { return Ok(()) } let res = unsafe { // if set or oldset is None, pass in null pointers instead libc::sigprocmask(how as libc::c_int, set.map_or_else(ptr::null::, |s| &s.sigset as *const libc::sigset_t), oldset.map_or_else(ptr::null_mut::, |os| &mut os.sigset as *mut libc::sigset_t)) }; Errno::result(res).map(drop) } /// Send a signal to a process /// /// # Arguments /// /// * `pid` - Specifies which processes should receive the signal. /// - If positive, specifies an individual process /// - If zero, the signal will be sent to all processes whose group /// ID is equal to the process group ID of the sender. This is a /// variant of [`killpg`]. /// - If `-1` and the process has super-user privileges, the signal /// is sent to all processes exclusing system processes. /// - If less than `-1`, the signal is sent to all processes whose /// process group ID is equal to the absolute value of `pid`. /// * `signal` - Signal to send. If `None`, error checking is performed /// but no signal is actually sent. /// /// See Also /// [`kill(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html) pub fn kill>>(pid: Pid, signal: T) -> Result<()> { let res = unsafe { libc::kill(pid.into(), match signal.into() { Some(s) => s as libc::c_int, None => 0, }) }; Errno::result(res).map(drop) } /// Send a signal to a process group /// /// # Arguments /// /// * `pgrp` - Process group to signal. If less then or equal 1, the behavior /// is platform-specific. /// * `signal` - Signal to send. If `None`, `killpg` will only preform error /// checking and won't send any signal. /// /// See Also [killpg(3)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/killpg.html). #[cfg(not(target_os = "fuchsia"))] pub fn killpg>>(pgrp: Pid, signal: T) -> Result<()> { let res = unsafe { libc::killpg(pgrp.into(), match signal.into() { Some(s) => s as libc::c_int, None => 0, }) }; Errno::result(res).map(drop) } /// Send a signal to the current thread /// /// See Also [raise(3)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/raise.html) pub fn raise(signal: Signal) -> Result<()> { let res = unsafe { libc::raise(signal as libc::c_int) }; Errno::result(res).map(drop) } } feature! { #![any(feature = "aio", feature = "signal")] /// Identifies a thread for [`SigevNotify::SigevThreadId`] #[cfg(target_os = "freebsd")] pub type type_of_thread_id = libc::lwpid_t; /// Identifies a thread for [`SigevNotify::SigevThreadId`] #[cfg(target_os = "linux")] pub type type_of_thread_id = libc::pid_t; /// Specifies the notification method used by a [`SigEvent`] // sigval is actually a union of a int and a void*. But it's never really used // as a pointer, because neither libc nor the kernel ever dereference it. nix // therefore presents it as an intptr_t, which is how kevent uses it. #[cfg(not(any(target_os = "openbsd", target_os = "redox")))] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub enum SigevNotify { /// No notification will be delivered SigevNone, /// Notify by delivering a signal to the process. SigevSignal { /// Signal to deliver signal: Signal, /// Will be present in the `si_value` field of the [`libc::siginfo_t`] /// structure of the queued signal. si_value: libc::intptr_t }, // Note: SIGEV_THREAD is not implemented because libc::sigevent does not // expose a way to set the union members needed by SIGEV_THREAD. /// Notify by delivering an event to a kqueue. #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] #[cfg_attr(docsrs, doc(cfg(all())))] SigevKevent { /// File descriptor of the kqueue to notify. kq: RawFd, /// Will be contained in the kevent's `udata` field. udata: libc::intptr_t }, /// Notify by delivering a signal to a thread. #[cfg(any(target_os = "freebsd", target_os = "linux"))] #[cfg_attr(docsrs, doc(cfg(all())))] SigevThreadId { /// Signal to send signal: Signal, /// LWP ID of the thread to notify thread_id: type_of_thread_id, /// Will be present in the `si_value` field of the [`libc::siginfo_t`] /// structure of the queued signal. si_value: libc::intptr_t }, } } #[cfg(not(any(target_os = "openbsd", target_os = "redox")))] #[cfg_attr(docsrs, doc(cfg(all())))] mod sigevent { feature! { #![any(feature = "aio", feature = "signal")] use std::mem; use std::ptr; use super::SigevNotify; #[cfg(any(target_os = "freebsd", target_os = "linux"))] use super::type_of_thread_id; /// Used to request asynchronous notification of the completion of certain /// events, such as POSIX AIO and timers. #[repr(C)] #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] pub struct SigEvent { sigevent: libc::sigevent } impl SigEvent { /// **Note:** this constructor does not allow the user to set the /// `sigev_notify_kevent_flags` field. That's considered ok because on FreeBSD /// at least those flags don't do anything useful. That field is part of a /// union that shares space with the more genuinely useful fields. /// /// **Note:** This constructor also doesn't allow the caller to set the /// `sigev_notify_function` or `sigev_notify_attributes` fields, which are /// required for `SIGEV_THREAD`. That's considered ok because on no operating /// system is `SIGEV_THREAD` the most efficient way to deliver AIO /// notification. FreeBSD and DragonFly BSD programs should prefer `SIGEV_KEVENT`. /// Linux, Solaris, and portable programs should prefer `SIGEV_THREAD_ID` or /// `SIGEV_SIGNAL`. That field is part of a union that shares space with the /// more genuinely useful `sigev_notify_thread_id` // Allow invalid_value warning on Fuchsia only. // See https://github.com/nix-rust/nix/issues/1441 #[cfg_attr(target_os = "fuchsia", allow(invalid_value))] pub fn new(sigev_notify: SigevNotify) -> SigEvent { let mut sev = unsafe { mem::MaybeUninit::::zeroed().assume_init() }; sev.sigev_notify = match sigev_notify { SigevNotify::SigevNone => libc::SIGEV_NONE, SigevNotify::SigevSignal{..} => libc::SIGEV_SIGNAL, #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] SigevNotify::SigevKevent{..} => libc::SIGEV_KEVENT, #[cfg(target_os = "freebsd")] SigevNotify::SigevThreadId{..} => libc::SIGEV_THREAD_ID, #[cfg(all(target_os = "linux", target_env = "gnu", not(target_arch = "mips")))] SigevNotify::SigevThreadId{..} => libc::SIGEV_THREAD_ID, #[cfg(all(target_os = "linux", target_env = "uclibc"))] SigevNotify::SigevThreadId{..} => libc::SIGEV_THREAD_ID, #[cfg(any(all(target_os = "linux", target_env = "musl"), target_arch = "mips"))] SigevNotify::SigevThreadId{..} => 4 // No SIGEV_THREAD_ID defined }; sev.sigev_signo = match sigev_notify { SigevNotify::SigevSignal{ signal, .. } => signal as libc::c_int, #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] SigevNotify::SigevKevent{ kq, ..} => kq, #[cfg(any(target_os = "linux", target_os = "freebsd"))] SigevNotify::SigevThreadId{ signal, .. } => signal as libc::c_int, _ => 0 }; sev.sigev_value.sival_ptr = match sigev_notify { SigevNotify::SigevNone => ptr::null_mut::(), SigevNotify::SigevSignal{ si_value, .. } => si_value as *mut libc::c_void, #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] SigevNotify::SigevKevent{ udata, .. } => udata as *mut libc::c_void, #[cfg(any(target_os = "freebsd", target_os = "linux"))] SigevNotify::SigevThreadId{ si_value, .. } => si_value as *mut libc::c_void, }; SigEvent::set_tid(&mut sev, &sigev_notify); SigEvent{sigevent: sev} } #[cfg(any(target_os = "freebsd", target_os = "linux"))] fn set_tid(sev: &mut libc::sigevent, sigev_notify: &SigevNotify) { sev.sigev_notify_thread_id = match *sigev_notify { SigevNotify::SigevThreadId { thread_id, .. } => thread_id, _ => 0 as type_of_thread_id }; } #[cfg(not(any(target_os = "freebsd", target_os = "linux")))] fn set_tid(_sev: &mut libc::sigevent, _sigev_notify: &SigevNotify) { } /// Return a copy of the inner structure pub fn sigevent(&self) -> libc::sigevent { self.sigevent } /// Returns a mutable pointer to the `sigevent` wrapped by `self` pub fn as_mut_ptr(&mut self) -> *mut libc::sigevent { &mut self.sigevent } } impl<'a> From<&'a libc::sigevent> for SigEvent { fn from(sigevent: &libc::sigevent) -> Self { SigEvent{ sigevent: *sigevent } } } } } #[cfg(test)] mod tests { #[cfg(not(target_os = "redox"))] use std::thread; use super::*; #[test] fn test_contains() { let mut mask = SigSet::empty(); mask.add(SIGUSR1); assert!(mask.contains(SIGUSR1)); assert!(!mask.contains(SIGUSR2)); let all = SigSet::all(); assert!(all.contains(SIGUSR1)); assert!(all.contains(SIGUSR2)); } #[test] fn test_clear() { let mut set = SigSet::all(); set.clear(); for signal in Signal::iterator() { assert!(!set.contains(signal)); } } #[test] fn test_from_str_round_trips() { for signal in Signal::iterator() { assert_eq!(signal.as_ref().parse::().unwrap(), signal); assert_eq!(signal.to_string().parse::().unwrap(), signal); } } #[test] fn test_from_str_invalid_value() { let errval = Err(Errno::EINVAL); assert_eq!("NOSIGNAL".parse::(), errval); assert_eq!("kill".parse::(), errval); assert_eq!("9".parse::(), errval); } #[test] fn test_extend() { let mut one_signal = SigSet::empty(); one_signal.add(SIGUSR1); let mut two_signals = SigSet::empty(); two_signals.add(SIGUSR2); two_signals.extend(&one_signal); assert!(two_signals.contains(SIGUSR1)); assert!(two_signals.contains(SIGUSR2)); } #[test] #[cfg(not(target_os = "redox"))] fn test_thread_signal_set_mask() { thread::spawn(|| { let prev_mask = SigSet::thread_get_mask() .expect("Failed to get existing signal mask!"); let mut test_mask = prev_mask; test_mask.add(SIGUSR1); assert!(test_mask.thread_set_mask().is_ok()); let new_mask = SigSet::thread_get_mask() .expect("Failed to get new mask!"); assert!(new_mask.contains(SIGUSR1)); assert!(!new_mask.contains(SIGUSR2)); prev_mask.thread_set_mask().expect("Failed to revert signal mask!"); }).join().unwrap(); } #[test] #[cfg(not(target_os = "redox"))] fn test_thread_signal_block() { thread::spawn(|| { let mut mask = SigSet::empty(); mask.add(SIGUSR1); assert!(mask.thread_block().is_ok()); assert!(SigSet::thread_get_mask().unwrap().contains(SIGUSR1)); }).join().unwrap(); } #[test] #[cfg(not(target_os = "redox"))] fn test_thread_signal_unblock() { thread::spawn(|| { let mut mask = SigSet::empty(); mask.add(SIGUSR1); assert!(mask.thread_unblock().is_ok()); assert!(!SigSet::thread_get_mask().unwrap().contains(SIGUSR1)); }).join().unwrap(); } #[test] #[cfg(not(target_os = "redox"))] fn test_thread_signal_swap() { thread::spawn(|| { let mut mask = SigSet::empty(); mask.add(SIGUSR1); mask.thread_block().unwrap(); assert!(SigSet::thread_get_mask().unwrap().contains(SIGUSR1)); let mut mask2 = SigSet::empty(); mask2.add(SIGUSR2); let oldmask = mask2.thread_swap_mask(SigmaskHow::SIG_SETMASK) .unwrap(); assert!(oldmask.contains(SIGUSR1)); assert!(!oldmask.contains(SIGUSR2)); assert!(SigSet::thread_get_mask().unwrap().contains(SIGUSR2)); }).join().unwrap(); } #[test] fn test_from_and_into_iterator() { let sigset = SigSet::from_iter(vec![Signal::SIGUSR1, Signal::SIGUSR2]); let signals = sigset.into_iter().collect::>(); assert_eq!(signals, [Signal::SIGUSR1, Signal::SIGUSR2]); } #[test] #[cfg(not(target_os = "redox"))] fn test_sigaction() { thread::spawn(|| { extern fn test_sigaction_handler(_: libc::c_int) {} extern fn test_sigaction_action(_: libc::c_int, _: *mut libc::siginfo_t, _: *mut libc::c_void) {} let handler_sig = SigHandler::Handler(test_sigaction_handler); let flags = SaFlags::SA_ONSTACK | SaFlags::SA_RESTART | SaFlags::SA_SIGINFO; let mut mask = SigSet::empty(); mask.add(SIGUSR1); let action_sig = SigAction::new(handler_sig, flags, mask); assert_eq!(action_sig.flags(), SaFlags::SA_ONSTACK | SaFlags::SA_RESTART); assert_eq!(action_sig.handler(), handler_sig); mask = action_sig.mask(); assert!(mask.contains(SIGUSR1)); assert!(!mask.contains(SIGUSR2)); let handler_act = SigHandler::SigAction(test_sigaction_action); let action_act = SigAction::new(handler_act, flags, mask); assert_eq!(action_act.handler(), handler_act); let action_dfl = SigAction::new(SigHandler::SigDfl, flags, mask); assert_eq!(action_dfl.handler(), SigHandler::SigDfl); let action_ign = SigAction::new(SigHandler::SigIgn, flags, mask); assert_eq!(action_ign.handler(), SigHandler::SigIgn); }).join().unwrap(); } #[test] #[cfg(not(target_os = "redox"))] fn test_sigwait() { thread::spawn(|| { let mut mask = SigSet::empty(); mask.add(SIGUSR1); mask.add(SIGUSR2); mask.thread_block().unwrap(); raise(SIGUSR1).unwrap(); assert_eq!(mask.wait().unwrap(), SIGUSR1); }).join().unwrap(); } }