handleSegfaultPosix
Function parameters
Parameters
- sig:i32
- info:*const posix.siginfo_t
- ctx_ptr:?*anyopaque
Type definitions in this namespace
Types
- SourceLocation
- Unresolved source locations can be represented with a single `usize` that
A fully-featured panic handler namespace which lowers all panics to calls to `panicFn`.
Functions
- FullPanic
- A fully-featured panic handler namespace which lowers all panics to calls to `panicFn`.
- lockStdErr
- Allows the caller to freely write to stderr until `unlockStdErr` is called.
- lockStderrWriter
- Allows the caller to freely write to stderr until `unlockStdErr` is called.
- Print to stderr, silently returning on failure.
- dumpHex
- Tries to print a hexadecimal view of the bytes, unbuffered, and ignores any error returned.
- dumpHexFallible
- Prints a hexadecimal view of the bytes, returning any error that occurs.
- dumpCurrentStackTrace
- Tries to print the current stack trace to stderr, unbuffered, and ignores any error returned.
- dumpCurrentStackTraceToWriter
- Prints the current stack trace to the provided writer.
- copyContext
- Copies one context to another, updating any internal pointers
- relocateContext
- Updates any internal pointers in the context to reflect its current location
- getContext
- Capture the current context.
- dumpStackTraceFromBase
- Tries to print the stack trace starting from the supplied base pointer to stderr,
- captureStackTrace
- Returns a slice with the same pointer as addresses, with a potentially smaller len.
- dumpStackTrace
- Tries to print a stack trace to stderr, unbuffered, and ignores any error returned.
- assert
- Invokes detectable illegal behavior when `ok` is `false`.
- assertReadable
- Invokes detectable illegal behavior when the provided slice is not mapped
- assertAligned
- Invokes detectable illegal behavior when the provided array is not aligned
- panic
- Equivalent to `@panic` but with a formatted message.
- panicExtra
- Equivalent to `@panic` but with a formatted message, and with an explicitly
- defaultPanic
- Dumps a stack trace to standard error, then aborts.
- attachSegfaultHandler
- Attaches a global SIGSEGV handler which calls `@panic("segmentation fault");`
- inValgrind
- Detect whether the program is being executed in the Valgrind virtual machine.
Deprecated because it returns the optimization mode of the standard
Values
- runtime_safety
- Deprecated because it returns the optimization mode of the standard
- sys_can_stack_trace
- = switch (builtin.cpu.arch) { // Observed to go into an infinite loop. // TODO: Make this work. .mips, .mipsel, .mips64, .mips64el, .s390x, => false, // `@returnAddress()` in LLVM 10 gives // "Non-Emscripten WebAssembly hasn't implemented __builtin_return_address". // On Emscripten, Zig only supports `@returnAddress()` in debug builds // because Emscripten's implementation is very slow. .wasm32, .wasm64, => native_os == .emscripten and builtin.mode == .Debug, // `@returnAddress()` is unsupported in LLVM 13. .bpfel, .bpfeb, => false, else => true, }
- have_ucontext
- = posix.ucontext_t != void
- ThreadContext
- Platform-specific thread state.
- have_getcontext
- = @TypeOf(posix.system.getcontext) != void
- have_segfault_handling_support
- Whether or not the current target can print useful debug information when a segfault occurs.
- default_enable_segfault_handler
- = runtime_safety and have_segfault_handling_support
Source
Implementation
fn handleSegfaultPosix(sig: i32, info: *const posix.siginfo_t, ctx_ptr: ?*anyopaque) callconv(.c) noreturn {
// Reset to the default handler so that if a segfault happens in this handler it will crash
// the process. Also when this handler returns, the original instruction will be repeated
// and the resulting segfault will crash the process rather than continually dump stack traces.
resetSegfaultHandler();
const addr = switch (native_os) {
.linux => @intFromPtr(info.fields.sigfault.addr),
.freebsd, .macos => @intFromPtr(info.addr),
.netbsd => @intFromPtr(info.info.reason.fault.addr),
.openbsd => @intFromPtr(info.data.fault.addr),
.solaris, .illumos => @intFromPtr(info.reason.fault.addr),
else => unreachable,
};
const code = if (native_os == .netbsd) info.info.code else info.code;
nosuspend switch (panic_stage) {
0 => {
panic_stage = 1;
_ = panicking.fetchAdd(1, .seq_cst);
{
lockStdErr();
defer unlockStdErr();
dumpSegfaultInfoPosix(sig, code, addr, ctx_ptr);
}
waitForOtherThreadToFinishPanicking();
},
else => {
// panic mutex already locked
dumpSegfaultInfoPosix(sig, code, addr, ctx_ptr);
},
};
// We cannot allow the signal handler to return because when it runs the original instruction
// again, the memory may be mapped and undefined behavior would occur rather than repeating
// the segfault. So we simply abort here.
posix.abort();
}