crash_handler/
linux.rs

1pub mod jmp;
2mod state;
3
4use crate::Error;
5
6/// The signals that we support catching and raising
7#[derive(Copy, Clone, PartialEq, Eq)]
8#[repr(i32)]
9pub enum Signal {
10    Abort = libc::SIGABRT,
11    Bus = libc::SIGBUS,
12    Fpe = libc::SIGFPE,
13    Illegal = libc::SIGILL,
14    Segv = libc::SIGSEGV,
15    Trap = libc::SIGTRAP,
16}
17
18impl Signal {
19    #[inline]
20    pub fn ignore(self) {
21        unsafe {
22            state::ignore_signal(self);
23        }
24    }
25}
26
27/// A Linux/Android signal handler
28pub struct CrashHandler;
29
30#[allow(clippy::unused_self)]
31impl CrashHandler {
32    /// Attaches the signal handler.
33    ///
34    /// The provided callback will be invoked if a signal is caught, providing a
35    /// [`crate::CrashContext`] with the details of the thread where the
36    /// signal was raised.
37    ///
38    /// The callback runs in a compromised context, so it is highly recommended
39    /// to not perform actions that may fail due to corrupted state that caused
40    /// or is a symptom of the original signal. This includes doing heap
41    /// allocations from the same allocator as the crashing code.
42    pub fn attach(on_crash: Box<dyn crate::CrashEvent>) -> Result<Self, Error> {
43        state::attach(on_crash)?;
44        Ok(Self)
45    }
46
47    /// Detaches the handler.
48    ///
49    /// This is done automatically when this [`CrashHandler`] is dropped.
50    #[inline]
51    pub fn detach(self) {
52        state::detach();
53    }
54
55    /// Set the process that is allowed to perform `ptrace` operations on the
56    /// current process.
57    ///
58    /// If you want to write a minidump from a child/external process when
59    /// a crash occurs in this process, you can use this method to set that
60    /// process as the only process allowed to use ptrace on this process.
61    ///
62    /// The process set by this method will be used by calling
63    /// `prctl(PR_SET_PTRACER, <the pid you want to ptrace this process>, ...)`
64    /// before handing off control to your user callback, presumably to trigger
65    /// dumping of your process via the specified process. By default if this
66    /// method is not called, `PR_SET_PTRACER_ANY` is used to allow any process
67    /// to dump the current process.
68    ///
69    /// Note that this is only needed if `/proc/sys/kernel/yama/ptrace_scope`
70    /// is 1 "restricted ptrace", but there is no harm in setting this if it is
71    /// in another mode.
72    ///
73    /// See <https://www.kernel.org/doc/Documentation/security/Yama.txt> for
74    /// the full documentation.
75    #[inline]
76    pub fn set_ptracer(&self, pid: Option<u32>) {
77        let mut lock = state::HANDLER.lock();
78
79        if let Some(handler) = &mut *lock {
80            handler.dump_process = pid;
81        }
82    }
83
84    /// Sends the specified user signal.
85    pub fn simulate_signal(&self, signal: u32) -> crate::CrashEventResult {
86        // Normally this would be an unsafe function, since this unsafe encompasses
87        // the entirety of the body, however the user is really not required to
88        // uphold any guarantees on their end, so no real need to declare the
89        // function itself unsafe.
90        unsafe {
91            let mut siginfo: libc::signalfd_siginfo = std::mem::zeroed();
92            siginfo.ssi_signo = signal;
93            siginfo.ssi_code = state::SI_USER;
94            siginfo.ssi_pid = std::process::id();
95
96            let mut context = std::mem::zeroed();
97            crash_context::crash_context_getcontext(&mut context);
98
99            let lock = state::HANDLER.lock();
100            if let Some(handler) = &*lock {
101                handler.handle_signal(
102                    &mut *(&mut siginfo as *mut libc::signalfd_siginfo).cast::<libc::siginfo_t>(),
103                    &mut *(&mut context as *mut crash_context::ucontext_t).cast::<libc::c_void>(),
104                )
105            } else {
106                crate::CrashEventResult::Handled(false)
107            }
108        }
109    }
110}
111
112impl Drop for CrashHandler {
113    fn drop(&mut self) {
114        state::detach();
115    }
116}
crash_handler/linux.rs

crash_handler/
linux.rs
