Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 467 insertions, 0 deletions

diff --git a/vendor/stacker/src/arch/asm.h b/vendor/stacker/src/arch/asm.h
new file mode 100644
index 000000000..56c9d2890
--- /dev/null
+++ b/vendor/stacker/src/arch/asm.h
@@ -0,0 +1,5 @@
+#if defined(APPLE) || (defined(WINDOWS) && defined(X86))
+#define GLOBAL(name) .globl _ ## name; _ ## name
+#else
+#define GLOBAL(name) .globl name; name
+#endif
diff --git a/vendor/stacker/src/arch/windows.c b/vendor/stacker/src/arch/windows.c
new file mode 100644
index 000000000..89485a0cc
--- /dev/null
+++ b/vendor/stacker/src/arch/windows.c
@@ -0,0 +1,5 @@
+#include <windows.h>

+

+PVOID __stacker_get_current_fiber() {

+    return GetCurrentFiber();

+}

diff --git a/vendor/stacker/src/lib.rs b/vendor/stacker/src/lib.rs
new file mode 100644
index 000000000..3c1d8891e
--- /dev/null
+++ b/vendor/stacker/src/lib.rs
@@ -0,0 +1,457 @@
+//! A library to help grow the stack when it runs out of space.
+//!
+//! This is an implementation of manually instrumented segmented stacks where points in a program's
+//! control flow are annotated with "maybe grow the stack here". Each point of annotation indicates
+//! how far away from the end of the stack it's allowed to be, plus the amount of stack to allocate
+//! if it does reach the end.
+//!
+//! Once a program has reached the end of its stack, a temporary stack on the heap is allocated and
+//! is switched to for the duration of a closure.
+//!
+//! For a set of lower-level primitives, consider the `psm` crate.
+//!
+//! # Examples
+//!
+//! ```
+//! // Grow the stack if we are within the "red zone" of 32K, and if we allocate
+//! // a new stack allocate 1MB of stack space.
+//! //
+//! // If we're already in bounds, just run the provided closure on current stack.
+//! stacker::maybe_grow(32 * 1024, 1024 * 1024, || {
+//!     // guaranteed to have at least 32K of stack
+//! });
+//! ```
+
+#![allow(improper_ctypes)]
+
+#[macro_use]
+extern crate cfg_if;
+extern crate libc;
+#[cfg(windows)]
+extern crate winapi;
+#[macro_use]
+extern crate psm;
+
+use std::cell::Cell;
+
+/// Grows the call stack if necessary.
+///
+/// This function is intended to be called at manually instrumented points in a program where
+/// recursion is known to happen quite a bit. This function will check to see if we're within
+/// `red_zone` bytes of the end of the stack, and if so it will allocate a new stack of at least
+/// `stack_size` bytes.
+///
+/// The closure `f` is guaranteed to run on a stack with at least `red_zone` bytes, and it will be
+/// run on the current stack if there's space available.
+#[inline(always)]
+pub fn maybe_grow<R, F: FnOnce() -> R>(red_zone: usize, stack_size: usize, callback: F) -> R {
+    // if we can't guess the remaining stack (unsupported on some platforms) we immediately grow
+    // the stack and then cache the new stack size (which we do know now because we allocated it.
+    let enough_space = match remaining_stack() {
+        Some(remaining) => remaining >= red_zone,
+        None => false,
+    };
+    if enough_space {
+        callback()
+    } else {
+        grow(stack_size, callback)
+    }
+}
+
+/// Always creates a new stack for the passed closure to run on.
+/// The closure will still be on the same thread as the caller of `grow`.
+/// This will allocate a new stack with at least `stack_size` bytes.
+pub fn grow<R, F: FnOnce() -> R>(stack_size: usize, callback: F) -> R {
+    // To avoid monomorphizing `_grow()` and everything it calls,
+    // we convert the generic callback to a dynamic one.
+    let mut opt_callback = Some(callback);
+    let mut ret = None;
+    let ret_ref = &mut ret;
+
+    // This wrapper around `callback` achieves two things:
+    // * It converts the `impl FnOnce` to a `dyn FnMut`.
+    //   `dyn` because we want it to not be generic, and
+    //   `FnMut` because we can't pass a `dyn FnOnce` around without boxing it.
+    // * It eliminates the generic return value, by writing it to the stack of this function.
+    //   Otherwise the closure would have to return an unsized value, which isn't possible.
+    let dyn_callback: &mut dyn FnMut() = &mut || {
+        let taken_callback = opt_callback.take().unwrap();
+        *ret_ref = Some(taken_callback());
+    };
+
+    _grow(stack_size, dyn_callback);
+    ret.unwrap()
+}
+
+/// Queries the amount of remaining stack as interpreted by this library.
+///
+/// This function will return the amount of stack space left which will be used
+/// to determine whether a stack switch should be made or not.
+pub fn remaining_stack() -> Option<usize> {
+    let current_ptr = current_stack_ptr();
+    get_stack_limit().map(|limit| current_ptr - limit)
+}
+
+psm_stack_information! (
+    yes {
+        fn current_stack_ptr() -> usize {
+            psm::stack_pointer() as usize
+        }
+    }
+    no {
+        #[inline(always)]
+        fn current_stack_ptr() -> usize {
+            unsafe {
+                let mut x = std::mem::MaybeUninit::<u8>::uninit();
+                // Unlikely to be ever exercised. As a fallback we execute a volatile read to a
+                // local (to hopefully defeat the optimisations that would make this local a static
+                // global) and take its address. This way we get a very approximate address of the
+                // current frame.
+                x.as_mut_ptr().write_volatile(42);
+                x.as_ptr() as usize
+            }
+        }
+    }
+);
+
+thread_local! {
+    static STACK_LIMIT: Cell<Option<usize>> = Cell::new(unsafe {
+        guess_os_stack_limit()
+    })
+}
+
+#[inline(always)]
+fn get_stack_limit() -> Option<usize> {
+    STACK_LIMIT.with(|s| s.get())
+}
+
+#[inline(always)]
+#[allow(unused)]
+fn set_stack_limit(l: Option<usize>) {
+    STACK_LIMIT.with(|s| s.set(l))
+}
+
+psm_stack_manipulation! {
+    yes {
+        struct StackRestoreGuard {
+            new_stack: *mut std::ffi::c_void,
+            stack_bytes: usize,
+            old_stack_limit: Option<usize>,
+        }
+
+        impl StackRestoreGuard {
+            #[cfg(target_arch = "wasm32")]
+            unsafe fn new(stack_bytes: usize, _page_size: usize) -> StackRestoreGuard {
+                let layout = std::alloc::Layout::from_size_align(stack_bytes, 16).unwrap();
+                let ptr = std::alloc::alloc(layout);
+                assert!(!ptr.is_null(), "unable to allocate stack");
+                StackRestoreGuard {
+                    new_stack: ptr as *mut _,
+                    stack_bytes,
+                    old_stack_limit: get_stack_limit(),
+                }
+            }
+
+            #[cfg(not(target_arch = "wasm32"))]
+            unsafe fn new(stack_bytes: usize, page_size: usize) -> StackRestoreGuard {
+                let new_stack = libc::mmap(
+                    std::ptr::null_mut(),
+                    stack_bytes,
+                    libc::PROT_NONE,
+                    libc::MAP_PRIVATE |
+                    libc::MAP_ANON,
+                    -1, // Some implementations assert fd = -1 if MAP_ANON is specified
+                    0
+                );
+                if new_stack == libc::MAP_FAILED {
+                    panic!("unable to allocate stack")
+                }
+                let guard = StackRestoreGuard {
+                    new_stack,
+                    stack_bytes,
+                    old_stack_limit: get_stack_limit(),
+                };
+                let above_guard_page = new_stack.add(page_size);
+                #[cfg(not(target_os = "openbsd"))]
+                let result = libc::mprotect(
+                    above_guard_page,
+                    stack_bytes - page_size,
+                    libc::PROT_READ | libc::PROT_WRITE
+                );
+                #[cfg(target_os = "openbsd")]
+                let result = if libc::mmap(
+                        above_guard_page,
+                        stack_bytes - page_size,
+                        libc::PROT_READ | libc::PROT_WRITE,
+                        libc::MAP_FIXED | libc::MAP_PRIVATE | libc::MAP_ANON | libc::MAP_STACK,
+                        -1,
+                        0) == above_guard_page {
+                    0
+                } else {
+                    -1
+                };
+                if result == -1 {
+                    drop(guard);
+                    panic!("unable to set stack permissions")
+                }
+                guard
+            }
+        }
+
+        impl Drop for StackRestoreGuard {
+            fn drop(&mut self) {
+                #[cfg(target_arch = "wasm32")]
+                unsafe {
+                    std::alloc::dealloc(
+                        self.new_stack as *mut u8,
+                        std::alloc::Layout::from_size_align_unchecked(self.stack_bytes, 16),
+                    );
+                }
+                #[cfg(not(target_arch = "wasm32"))]
+                unsafe {
+                    // FIXME: check the error code and decide what to do with it.
+                    // Perhaps a debug_assertion?
+                    libc::munmap(self.new_stack, self.stack_bytes);
+                }
+                set_stack_limit(self.old_stack_limit);
+            }
+        }
+
+        fn _grow(stack_size: usize, callback: &mut dyn FnMut()) {
+            // Calculate a number of pages we want to allocate for the new stack.
+            // For maximum portability we want to produce a stack that is aligned to a page and has
+            // a size that’s a multiple of page size. Furthermore we want to allocate two extras pages
+            // for the stack guard. To achieve that we do our calculations in number of pages and
+            // convert to bytes last.
+            let page_size = page_size();
+            let requested_pages = stack_size
+                .checked_add(page_size - 1)
+                .expect("unreasonably large stack requested") / page_size;
+            let stack_pages = std::cmp::max(1, requested_pages) + 2;
+            let stack_bytes = stack_pages.checked_mul(page_size)
+                .expect("unreasonably large stack requesteed");
+
+            // Next, there are a couple of approaches to how we allocate the new stack. We take the
+            // most obvious path and use `mmap`. We also `mprotect` a guard page into our
+            // allocation.
+            //
+            // We use a guard pattern to ensure we deallocate the allocated stack when we leave
+            // this function and also try to uphold various safety invariants required by `psm`
+            // (such as not unwinding from the callback we pass to it).
+            //
+            // Other than that this code has no meaningful gotchas.
+            unsafe {
+                let guard = StackRestoreGuard::new(stack_bytes, page_size);
+                let above_guard_page = guard.new_stack.add(page_size);
+                set_stack_limit(Some(above_guard_page as usize));
+                let panic = psm::on_stack(above_guard_page as *mut _, stack_size, move || {
+                    std::panic::catch_unwind(std::panic::AssertUnwindSafe(callback)).err()
+                });
+                drop(guard);
+                if let Some(p) = panic {
+                    std::panic::resume_unwind(p);
+                }
+            }
+        }
+
+        fn page_size() -> usize {
+            // FIXME: consider caching the page size.
+            #[cfg(not(target_arch = "wasm32"))]
+            unsafe { libc::sysconf(libc::_SC_PAGE_SIZE) as usize }
+            #[cfg(target_arch = "wasm32")]
+            { 65536 }
+        }
+    }
+
+    no {
+        #[cfg(not(windows))]
+        fn _grow(stack_size: usize, callback: &mut dyn FnMut()) {
+            drop(stack_size);
+            callback();
+        }
+    }
+}
+
+cfg_if! {
+    if #[cfg(windows)] {
+        use std::ptr;
+        use std::io;
+
+        use winapi::shared::basetsd::*;
+        use winapi::shared::minwindef::{LPVOID, BOOL};
+        use winapi::shared::ntdef::*;
+        use winapi::um::fibersapi::*;
+        use winapi::um::memoryapi::*;
+        use winapi::um::processthreadsapi::*;
+        use winapi::um::winbase::*;
+
+        // Make sure the libstacker.a (implemented in C) is linked.
+        // See https://github.com/rust-lang/rust/issues/65610
+        #[link(name="stacker")]
+        extern {
+            fn __stacker_get_current_fiber() -> PVOID;
+        }
+
+        struct FiberInfo<F> {
+            callback: std::mem::MaybeUninit<F>,
+            panic: Option<Box<dyn std::any::Any + Send + 'static>>,
+            parent_fiber: LPVOID,
+        }
+
+        unsafe extern "system" fn fiber_proc<F: FnOnce()>(data: LPVOID) {
+            // This function is the entry point to our inner fiber, and as argument we get an
+            // instance of `FiberInfo`. We will set-up the "runtime" for the callback and execute
+            // it.
+            let data = &mut *(data as *mut FiberInfo<F>);
+            let old_stack_limit = get_stack_limit();
+            set_stack_limit(guess_os_stack_limit());
+            let callback = data.callback.as_ptr();
+            data.panic = std::panic::catch_unwind(std::panic::AssertUnwindSafe(callback.read())).err();
+
+            // Restore to the previous Fiber
+            set_stack_limit(old_stack_limit);
+            SwitchToFiber(data.parent_fiber);
+            return;
+        }
+
+        fn _grow(stack_size: usize, callback: &mut dyn FnMut()) {
+            // Fibers (or stackful coroutines) is the only official way to create new stacks on the
+            // same thread on Windows. So in order to extend the stack we create fiber and switch
+            // to it so we can use it's stack. After running `callback` within our fiber, we switch
+            // back to the current stack and destroy the fiber and its associated stack.
+            unsafe {
+                let was_fiber = IsThreadAFiber() == TRUE as BOOL;
+                let mut data = FiberInfo {
+                    callback: std::mem::MaybeUninit::new(callback),
+                    panic: None,
+                    parent_fiber: {
+                        if was_fiber {
+                            // Get a handle to the current fiber. We need to use a C implementation
+                            // for this as GetCurrentFiber is an header only function.
+                            __stacker_get_current_fiber()
+                        } else {
+                            // Convert the current thread to a fiber, so we are able to switch back
+                            // to the current stack. Threads coverted to fibers still act like
+                            // regular threads, but they have associated fiber data. We later
+                            // convert it back to a regular thread and free the fiber data.
+                            ConvertThreadToFiber(ptr::null_mut())
+                        }
+                    },
+                };
+
+                if data.parent_fiber.is_null() {
+                    panic!("unable to convert thread to fiber: {}", io::Error::last_os_error());
+                }
+
+                let fiber = CreateFiber(
+                    stack_size as SIZE_T,
+                    Some(fiber_proc::<&mut dyn FnMut()>),
+                    &mut data as *mut FiberInfo<&mut dyn FnMut()> as *mut _,
+                );
+                if fiber.is_null() {
+                    panic!("unable to allocate fiber: {}", io::Error::last_os_error());
+                }
+
+                // Switch to the fiber we created. This changes stacks and starts executing
+                // fiber_proc on it. fiber_proc will run `callback` and then switch back to run the
+                // next statement.
+                SwitchToFiber(fiber);
+                DeleteFiber(fiber);
+
+                // Clean-up.
+                if !was_fiber {
+                    if ConvertFiberToThread() == 0 {
+                        // FIXME: Perhaps should not panic here?
+                        panic!("unable to convert back to thread: {}", io::Error::last_os_error());
+                    }
+                }
+                if let Some(p) = data.panic {
+                    std::panic::resume_unwind(p);
+                }
+            }
+        }
+
+        #[inline(always)]
+        fn get_thread_stack_guarantee() -> usize {
+            let min_guarantee = if cfg!(target_pointer_width = "32") {
+                0x1000
+            } else {
+                0x2000
+            };
+            let mut stack_guarantee = 0;
+            unsafe {
+                // Read the current thread stack guarantee
+                // This is the stack reserved for stack overflow
+                // exception handling.
+                // This doesn't return the true value so we need
+                // some further logic to calculate the real stack
+                // guarantee. This logic is what is used on x86-32 and
+                // x86-64 Windows 10. Other versions and platforms may differ
+                SetThreadStackGuarantee(&mut stack_guarantee)
+            };
+            std::cmp::max(stack_guarantee, min_guarantee) as usize + 0x1000
+        }
+
+        #[inline(always)]
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            // Query the allocation which contains our stack pointer in order
+            // to discover the size of the stack
+            //
+            // FIXME: we could read stack base from the TIB, specifically the 3rd element of it.
+            type QueryT = winapi::um::winnt::MEMORY_BASIC_INFORMATION;
+            let mut mi = std::mem::MaybeUninit::<QueryT>::uninit();
+            VirtualQuery(
+                psm::stack_pointer() as *const _,
+                mi.as_mut_ptr(),
+                std::mem::size_of::<QueryT>() as SIZE_T,
+            );
+            Some(mi.assume_init().AllocationBase as usize + get_thread_stack_guarantee() + 0x1000)
+        }
+    } else if #[cfg(any(target_os = "linux", target_os="solaris", target_os = "netbsd"))] {
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            let mut attr = std::mem::MaybeUninit::<libc::pthread_attr_t>::uninit();
+            assert_eq!(libc::pthread_attr_init(attr.as_mut_ptr()), 0);
+            assert_eq!(libc::pthread_getattr_np(libc::pthread_self(),
+                                                attr.as_mut_ptr()), 0);
+            let mut stackaddr = std::ptr::null_mut();
+            let mut stacksize = 0;
+            assert_eq!(libc::pthread_attr_getstack(
+                attr.as_ptr(), &mut stackaddr, &mut stacksize
+            ), 0);
+            assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0);
+            Some(stackaddr as usize)
+        }
+    } else if #[cfg(any(target_os = "freebsd", target_os = "dragonfly"))] {
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            let mut attr = std::mem::MaybeUninit::<libc::pthread_attr_t>::uninit();
+            assert_eq!(libc::pthread_attr_init(attr.as_mut_ptr()), 0);
+            assert_eq!(libc::pthread_attr_get_np(libc::pthread_self(), attr.as_mut_ptr()), 0);
+            let mut stackaddr = std::ptr::null_mut();
+            let mut stacksize = 0;
+            assert_eq!(libc::pthread_attr_getstack(
+                attr.as_ptr(), &mut stackaddr, &mut stacksize
+            ), 0);
+            assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0);
+            Some(stackaddr as usize)
+        }
+    } else if #[cfg(target_os = "openbsd")] {
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            let mut stackinfo = std::mem::MaybeUninit::<libc::stack_t>::uninit();
+            assert_eq!(libc::pthread_stackseg_np(libc::pthread_self(), stackinfo.as_mut_ptr()), 0);
+            Some(stackinfo.assume_init().ss_sp as usize - stackinfo.assume_init().ss_size)
+        }
+    } else if #[cfg(target_os = "macos")] {
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            Some(libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize -
+                libc::pthread_get_stacksize_np(libc::pthread_self()) as usize)
+        }
+    } else {
+        // fallback for other platforms is to always increase the stack if we're on
+        // the root stack. After we increased the stack once, we know the new stack
+        // size and don't need this pessimization anymore
+        #[inline(always)]
+        unsafe fn guess_os_stack_limit() -> Option<usize> {
+            None
+        }
+    }
+}