1 use crate::error::ErrorStack;
2 use crate::util;
3 use foreign_types::{ForeignType, ForeignTypeRef};
4 use libc::{c_char, c_int, c_void};
5 use std::any::Any;
6 use std::panic::{self, AssertUnwindSafe};
7 use std::slice;
8
9 /// Wraps a user-supplied callback and a slot for panics thrown inside the callback (while FFI
10 /// frames are on the stack).
11 ///
12 /// When dropped, checks if the callback has panicked, and resumes unwinding if so.
13 pub struct CallbackState<F> {
14 /// The user callback. Taken out of the `Option` when called.
15 cb: Option<F>,
16 /// If the callback panics, we place the panic object here, to be re-thrown once OpenSSL
17 /// returns.
18 panic: Option<Box<dyn Any + Send + 'static>>,
19 }
20
21 impl<F> CallbackState<F> {
new(callback: F) -> Self22 pub fn new(callback: F) -> Self {
23 CallbackState {
24 cb: Some(callback),
25 panic: None,
26 }
27 }
28 }
29
30 impl<F> Drop for CallbackState<F> {
drop(&mut self)31 fn drop(&mut self) {
32 if let Some(panic) = self.panic.take() {
33 panic::resume_unwind(panic);
34 }
35 }
36 }
37
38 /// Password callback function, passed to private key loading functions.
39 ///
40 /// `cb_state` is expected to be a pointer to a `CallbackState`.
invoke_passwd_cb<F>( buf: *mut c_char, size: c_int, _rwflag: c_int, cb_state: *mut c_void, ) -> c_int where F: FnOnce(&mut [u8]) -> Result<usize, ErrorStack>,41 pub unsafe extern "C" fn invoke_passwd_cb<F>(
42 buf: *mut c_char,
43 size: c_int,
44 _rwflag: c_int,
45 cb_state: *mut c_void,
46 ) -> c_int
47 where
48 F: FnOnce(&mut [u8]) -> Result<usize, ErrorStack>,
49 {
50 let callback = &mut *(cb_state as *mut CallbackState<F>);
51
52 let result = panic::catch_unwind(AssertUnwindSafe(|| {
53 let pass_slice = util::from_raw_parts_mut(buf as *mut u8, size as usize);
54 callback.cb.take().unwrap()(pass_slice)
55 }));
56
57 match result {
58 Ok(Ok(len)) => len as c_int,
59 Ok(Err(_)) => {
60 // FIXME restore error stack
61 0
62 }
63 Err(err) => {
64 callback.panic = Some(err);
65 0
66 }
67 }
68 }
69
70 pub trait ForeignTypeExt: ForeignType {
from_ptr_opt(ptr: *mut Self::CType) -> Option<Self>71 unsafe fn from_ptr_opt(ptr: *mut Self::CType) -> Option<Self> {
72 if ptr.is_null() {
73 None
74 } else {
75 Some(Self::from_ptr(ptr))
76 }
77 }
78 }
79 impl<FT: ForeignType> ForeignTypeExt for FT {}
80
81 pub trait ForeignTypeRefExt: ForeignTypeRef {
from_const_ptr<'a>(ptr: *const Self::CType) -> &'a Self82 unsafe fn from_const_ptr<'a>(ptr: *const Self::CType) -> &'a Self {
83 Self::from_ptr(ptr as *mut Self::CType)
84 }
85
from_const_ptr_opt<'a>(ptr: *const Self::CType) -> Option<&'a Self>86 unsafe fn from_const_ptr_opt<'a>(ptr: *const Self::CType) -> Option<&'a Self> {
87 if ptr.is_null() {
88 None
89 } else {
90 Some(Self::from_const_ptr(ptr as *mut Self::CType))
91 }
92 }
93 }
94 impl<FT: ForeignTypeRef> ForeignTypeRefExt for FT {}
95
96 /// The same as `slice::from_raw_parts`, except that `data` may be `NULL` if
97 /// `len` is 0.
from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T]98 pub unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T] {
99 if len == 0 {
100 &[]
101 } else {
102 // Using this to implement the preferred API
103 #[allow(clippy::disallowed_methods)]
104 slice::from_raw_parts(data, len)
105 }
106 }
107
108 /// The same as `slice::from_raw_parts_mut`, except that `data` may be `NULL`
109 /// if `len` is 0.
from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T]110 pub unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T] {
111 if len == 0 {
112 &mut []
113 } else {
114 // Using this to implement the preferred API
115 #[allow(clippy::disallowed_methods)]
116 slice::from_raw_parts_mut(data, len)
117 }
118 }