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pub mod jmp;
mod state;
use crate::Error;
/// The signals that we support catching and raising
#[derive(Copy, Clone, PartialEq, Eq)]
#[repr(i32)]
pub enum Signal {
Abort = libc::SIGABRT,
Bus = libc::SIGBUS,
Fpe = libc::SIGFPE,
Illegal = libc::SIGILL,
Segv = libc::SIGSEGV,
Trap = libc::SIGTRAP,
}
impl Signal {
#[inline]
pub fn ignore(self) {
unsafe {
state::ignore_signal(self);
}
}
}
/// A Linux/Android signal handler
pub struct CrashHandler;
#[allow(clippy::unused_self)]
impl CrashHandler {
/// Attaches the signal handler.
///
/// The provided callback will be invoked if a signal is caught, providing a
/// [`crate::CrashContext`] with the details of the thread where the
/// signal was raised.
///
/// The callback runs in a compromised context, so it is highly recommended
/// to not perform actions that may fail due to corrupted state that caused
/// or is a symptom of the original signal. This includes doing heap
/// allocations from the same allocator as the crashing code.
pub fn attach(on_crash: Box<dyn crate::CrashEvent>) -> Result<Self, Error> {
state::attach(on_crash)?;
Ok(Self)
}
/// Detaches the handler.
///
/// This is done automatically when this [`CrashHandler`] is dropped.
#[inline]
pub fn detach(self) {
state::detach();
}
/// Set the process that is allowed to perform `ptrace` operations on the
/// current process.
///
/// If you want to write a minidump from a child/external process when
/// a crash occurs in this process, you can use this method to set that
/// process as the only process allowed to use ptrace on this process.
///
/// The process set by this method will be used by calling
/// `prctl(PR_SET_PTRACER, <the pid you want to ptrace this process>, ...)`
/// before handing off control to your user callback, presumably to trigger
/// dumping of your process via the specified process. By default if this
/// method is not called, `PR_SET_PTRACER_ANY` is used to allow any process
/// to dump the current process.
///
/// Note that this is only needed if `/proc/sys/kernel/yama/ptrace_scope`
/// is 1 "restricted ptrace", but there is no harm in setting this if it is
/// in another mode.
///
/// See <https://www.kernel.org/doc/Documentation/security/Yama.txt> for
/// the full documentation.
#[inline]
pub fn set_ptracer(&self, pid: Option<u32>) {
let mut lock = state::HANDLER.lock();
if let Some(handler) = &mut *lock {
handler.dump_process = pid;
}
}
/// Sends the specified user signal.
pub fn simulate_signal(&self, signal: u32) -> crate::CrashEventResult {
// Normally this would be an unsafe function, since this unsafe encompasses
// the entirety of the body, however the user is really not required to
// uphold any guarantees on their end, so no real need to declare the
// function itself unsafe.
unsafe {
let mut siginfo: libc::signalfd_siginfo = std::mem::zeroed();
siginfo.ssi_signo = signal;
siginfo.ssi_code = state::SI_USER;
siginfo.ssi_pid = std::process::id();
let mut context = std::mem::zeroed();
crash_context::crash_context_getcontext(&mut context);
let lock = state::HANDLER.lock();
if let Some(handler) = &*lock {
handler.handle_signal(
&mut *(&mut siginfo as *mut libc::signalfd_siginfo).cast::<libc::siginfo_t>(),
&mut *(&mut context as *mut crash_context::ucontext_t).cast::<libc::c_void>(),
)
} else {
crate::CrashEventResult::Handled(false)
}
}
}
}
impl Drop for CrashHandler {
fn drop(&mut self) {
state::detach();
}
}