make dump_registers method public (#367)

* make dump_registers method public

* be smart about getting the ucontext

* more docu

libafl/src/bolts/minibsod.rs

@@ -1,12 +1,16 @@
 //! Implements a mini-bsod generator
+//! It dumps all important registers and prints a stacktrace.
+//! You may use the [`crate::bolts::os::unix_signals::ucontext`]
+//! function to get a [`ucontext_t`].
 
 use libc::siginfo_t;
 use std::io::{BufWriter, Write};
 
 use crate::bolts::os::unix_signals::{ucontext_t, Signal};
 
+/// Write the contens of all important registers
 #[cfg(all(target_os = "linux", target_arch = "x86_64"))]
-fn dump_registers<W: Write>(
+pub fn dump_registers<W: Write>(
     writer: &mut BufWriter<W>,
     ucontext: &ucontext_t,
 ) -> Result<(), std::io::Error> {
@@ -39,11 +43,12 @@ fn dump_registers<W: Write>(
     Ok(())
 }
 
+/// Write the contens of all important registers
 #[cfg(all(
     any(target_os = "linux", target_os = "android"),
     target_arch = "aarch64"
 ))]
-fn dump_registers<W: Write>(
+pub fn dump_registers<W: Write>(
     writer: &mut BufWriter<W>,
     ucontext: &ucontext_t,
 ) -> Result<(), std::io::Error> {
@@ -62,8 +67,9 @@ fn dump_registers<W: Write>(
     Ok(())
 }
 
+/// Write the contens of all important registers
 #[cfg(all(target_vendor = "apple", target_arch = "aarch64"))]
-fn dump_registers<W: Write>(
+pub fn dump_registers<W: Write>(
     writer: &mut BufWriter<W>,
     ucontext: &ucontext_t,
 ) -> Result<(), std::io::Error> {
@@ -85,9 +91,10 @@ fn dump_registers<W: Write>(
     Ok(())
 }
 
+/// Write the contens of all important registers
 #[allow(clippy::unnecessary_wraps, clippy::similar_names)]
 #[cfg(all(target_vendor = "apple", target_arch = "x86_64"))]
-fn dump_registers<W: Write>(
+pub fn dump_registers<W: Write>(
     writer: &mut BufWriter<W>,
     ucontext: &ucontext_t,
 ) -> Result<(), std::io::Error> {

libafl/src/bolts/os/unix_signals.rs

@@ -3,9 +3,7 @@ use alloc::vec::Vec;
 use core::{
     cell::UnsafeCell,
     fmt::{self, Display, Formatter},
-    mem,
+    mem, ptr,
-    mem::MaybeUninit,
-    ptr,
     ptr::write_volatile,
     sync::atomic::{compiler_fence, Ordering},
 };
@@ -244,11 +242,15 @@ pub unsafe fn setup_signal_handler<T: 'static + Handler>(handler: &mut T) -> Res
 
 /// Function to get the current [`ucontext_t`] for this process.
 /// This calls the libc `getcontext` function under the hood.
+/// It can be useful, for example for `dump_regs`.
+/// Note that calling this method may, of course, alter the state.
 /// We wrap it here, as it seems to be (currently)
 /// not available on `MacOS` in the `libc` crate.
 #[cfg(unix)]
+#[allow(clippy::inline_always)] // we assume that inlining will destroy less state
+#[inline(always)]
 pub fn ucontext() -> Result<ucontext_t, Error> {
-    let mut ucontext = unsafe { MaybeUninit::zeroed().assume_init() };
+    let mut ucontext = unsafe { mem::zeroed() };
     if unsafe { getcontext(&mut ucontext) } == 0 {
         Ok(ucontext)
     } else {