From 8119f06ca5ca50a677cf584cbe816500153ce783 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonas@schievink.net>
Date: Tue, 14 Jun 2016 18:12:50 +0200
Subject: Move into utility module

---
 openssl/src/crypto/util.rs | 58 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 openssl/src/crypto/util.rs

(limited to 'openssl/src/crypto/util.rs')

diff --git a/openssl/src/crypto/util.rs b/openssl/src/crypto/util.rs
new file mode 100644
index 00000000..85df86b7
--- /dev/null
+++ b/openssl/src/crypto/util.rs
@@ -0,0 +1,58 @@
+use libc::{c_int, c_char, c_void};
+
+use std::any::Any;
+use std::panic;
+use std::slice;
+
+/// Wraps a user-supplied callback and a slot for panics thrown inside the callback (while FFI
+/// frames are on the stack).
+///
+/// When dropped, checks if the callback has panicked, and resumes unwinding if so.
+pub struct CallbackState<F> {
+    /// The user callback. Taken out of the `Option` when called.
+    cb: Option<F>,
+    /// If the callback panics, we place the panic object here, to be re-thrown once OpenSSL
+    /// returns.
+    panic: Option<Box<Any + Send + 'static>>,
+}
+
+impl<F> CallbackState<F> {
+    pub fn new(callback: F) -> Self {
+        CallbackState {
+            cb: Some(callback),
+            panic: None,
+        }
+    }
+}
+
+impl<F> Drop for CallbackState<F> {
+    fn drop(&mut self) {
+        if let Some(panic) = self.panic.take() {
+            panic::resume_unwind(panic);
+        }
+    }
+}
+
+/// Password callback function, passed to private key loading functions.
+///
+/// `cb_state` is expected to be a pointer to a `CallbackState`.
+pub extern "C" fn invoke_passwd_cb<F>(buf: *mut c_char,
+                                      size: c_int,
+                                      _rwflag: c_int,
+                                      cb_state: *mut c_void)
+                                      -> c_int
+                                      where F: FnMut(&mut [i8]) -> usize {
+    let result = panic::catch_unwind(|| {
+        // build a `i8` slice to pass to the user callback
+        let pass_slice = unsafe { slice::from_raw_parts_mut(buf, size as usize) };
+        let callback = unsafe { &mut *(cb_state as *mut CallbackState<F>) };
+
+        callback.cb.take().unwrap()(pass_slice)
+    });
+
+    if let Ok(len) = result {
+        return len as c_int;
+    } else {
+        return 0;
+    }
+}
-- 
cgit v1.2.3


From f24ab2693636f16ce71a171a4d4d63bd0f5bbea0 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonas@schievink.net>
Date: Sun, 26 Jun 2016 19:44:53 +0200
Subject: FnMut -> FnOnce, update docs

---
 openssl/src/crypto/util.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'openssl/src/crypto/util.rs')

diff --git a/openssl/src/crypto/util.rs b/openssl/src/crypto/util.rs
index 85df86b7..be72aa59 100644
--- a/openssl/src/crypto/util.rs
+++ b/openssl/src/crypto/util.rs
@@ -41,7 +41,7 @@ pub extern "C" fn invoke_passwd_cb<F>(buf: *mut c_char,
                                       _rwflag: c_int,
                                       cb_state: *mut c_void)
                                       -> c_int
-                                      where F: FnMut(&mut [i8]) -> usize {
+                                      where F: FnOnce(&mut [i8]) -> usize {
     let result = panic::catch_unwind(|| {
         // build a `i8` slice to pass to the user callback
         let pass_slice = unsafe { slice::from_raw_parts_mut(buf, size as usize) };
-- 
cgit v1.2.3