Linux/Android

On Linux this is done by handling signals, namely the following.

One important detail of the Linux signal handling is that this crate hooks pthread_create so that an alternate signal stack is always installed on every thread. [std::thread::Thread] already does this, however hooking pthread_create allows us to ensure this occurs for threads created from eg. C/C++ code as well. An alternate stack is necessary to reliably handle a SIGSEGV caused by a stack overflow, as signals are otherwise handled on the same stack that raised the signal.

SIGABRT

Signal sent to a process to tell it to abort, i.e. to terminate. The signal is usually initiated by the process itself when it calls std::process::abort or libc::abort, but it can be sent to the process from outside itself like any other signal.

SIGBUS

Signal sent to a process when it causes a bus error.

SIGFPE

Signal sent to a process when it executes an erroneous arithmetic operation. Though it stands for floating point exception this signal covers integer operations as well.

SIGILL

Signal sent to a process when it attempts to execute an illegal, malformed, unknown, or privileged, instruction.

SIGSEGV

Signal sent to a process when it makes an invalid virtual memory reference, a segmentation fault. This covers infamous null pointer access, out of bounds access, use after free, stack overflows, etc.

SIGTRAP

Signal sent to a process when a trap is raised, eg. a breakpoint or debug assertion.

Windows

On Windows we catch exceptions, which cover a wide range of crash reasons, as well as invalid parameters and purecall

MacOS

On Macos we use exception ports. Exception ports are the first layer that exceptions are filtered, from a thread level, to a process (task) level, and finally to a host level.

If no user ports have been registered, the default Macos implementation is to convert the Mach exception into an equivalent Unix signal and deliver it to any registered signal handlers before performing the default action for the exception/signal (ie process termination). This means that if you use this crate in conjunction with signal handling on MacOs, you will not get the results you expect as the exception port used by this crate will take precedence over the signal handler. See this issue for a concrete example.

Note that there is one exception to the above, which is that SIGABRT is handled by a signal handler, as there is no equivalent Mach exception for it.

EXC_BAD_ACCESS

Covers similar crashes as SIGSEGV and SIGBUS

EXC_BAD_INSTRUCTION

Covers similar crashes as SIGILL

EXC_ARITHMETIC

Covers similar crashes as SIGFPE

EXC_BREAKPOINT

Covers similar crashes as SIGTRAP

Contribution

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License

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• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

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