[libc++] Don't return uninitialized data from random_device::operator()
Make sure we appropriately retry calls to read if the return result is
less than what we asked for.
Additionally, check and handle IO errors: EINTR results in the read
operation getting restarted; other errors turn into exceptions.
llvm-svn: 210061
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 2dfdfdf45c4c26a628527a542d9c4deaaf300ea1
diff --git a/src/random.cpp b/src/random.cpp
index 21e2168..86017ef 100644
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -62,7 +62,22 @@
random_device::operator()()
{
unsigned r;
- read(__f_, &r, sizeof(r));
+ size_t n = sizeof(r);
+ char* p = reinterpret_cast<char*>(&r);
+ while (n > 0)
+ {
+ ssize_t s = read(__f_, p, n);
+ if (s == 0)
+ __throw_system_error(ENODATA, "random_device got EOF");
+ if (s == -1)
+ {
+ if (errno != EINTR)
+ __throw_system_error(errno, "random_device got an unexpected error");
+ continue;
+ }
+ n -= static_cast<size_t>(s);
+ p += static_cast<size_t>(s);
+ }
return r;
}
#endif // defined(_WIN32)