This patch use ioctl to get entropy of std::random_device using
/dev/random and /dev/urandom.
Regenerated files are mentioned in ChangeLog but not included
in the patch.
2017-03-12 Xi Ruoyao <r...@stu.xidian.edu.cn>
PR libstdc++/67578
* config.h.in: Regenerate.
* configure: Regenerate.
* configure.ac: Check for linux/random.h.
* config/abi/pre/gnu.ver: Add a new symbol.
* include/bits/random.h (random_device::_M_getentropy):
Declare new function to get entropy using ioctl.
(random_device::entropy): Call it.
* src/c++11/random.cc (random_device::_M_getentropy):
Implement new function.
* config/abi/post/x86_64-linux-gnu/baseline_symbols.txt:
Regenerate.
* config/abi/post/i386-linux-gnu/baseline_symbols.txt:
Regenerate.
* config/abi/post/i486-linux-gnu/baseline_symbols.txt:
Regenerate.
---
libstdc++-v3/config/abi/pre/gnu.ver | 3 ++
libstdc++-v3/configure.ac | 2 +-
libstdc++-v3/include/bits/random.h | 9 +++++-
libstdc++-v3/src/c++11/random.cc | 36 ++++++++++++++++++++++
9 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/libstdc++-v3/config/abi/pre/gnu.ver
b/libstdc++-v3/config/abi/pre/gnu.ver
index 3e6e70b..39ad330 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1963,6 +1963,9 @@ GLIBCXX_3.4.23 {
_ZNSt13__future_base13_State_baseV211_Make_ready6_M_setEv;
#endif
+ # std::random_device::_M_getentropy() const
+ _ZNKSt13random_device13_M_getentropyEv;
+
} GLIBCXX_3.4.22;
# Symbols in the support library (libsupc++) have their own tag.
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 8e97350..270dcba 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -237,7 +237,7 @@ AC_CHECK_HEADERS([endian.h execinfo.h float.h fp.h ieeefp.h
inttypes.h \
locale.h machine/endian.h machine/param.h nan.h stdint.h stdlib.h string.h \
strings.h sys/ipc.h sys/isa_defs.h sys/machine.h sys/param.h \
sys/resource.h sys/sem.h sys/stat.h sys/time.h sys/types.h unistd.h \
-wchar.h wctype.h])
+wchar.h wctype.h linux/random.h])
# Only do link tests if native. Else, hardcode.
if $GLIBCXX_IS_NATIVE; then
diff --git a/libstdc++-v3/include/bits/random.h
b/libstdc++-v3/include/bits/random.h
index d39cc3e..bb761ec 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -1603,7 +1603,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
double
entropy() const noexcept
- { return 0.0; }
+ {
+#ifdef _GLIBCXX_USE_RANDOM_TR1
+ return this->_M_getentropy();
+#else
+ return 0.0;
+#endif
+ }
result_type
operator()()
@@ -1627,6 +1633,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
result_type _M_getval();
result_type _M_getval_pretr1();
+ double _M_getentropy() const noexcept;
union
{
diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc
index df79874..414ddc3 100644
--- a/libstdc++-v3/src/c++11/random.cc
+++ b/libstdc++-v3/src/c++11/random.cc
@@ -38,6 +38,14 @@
# include <unistd.h>
#endif
+#ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
+# include <sys/ioctl.h>
+#endif
+
+#ifdef _GLIBCXX_HAVE_LINUX_RANDOM_H
+# include <linux/random.h>
+#endif
+
namespace std _GLIBCXX_VISIBILITY(default)
{
namespace
@@ -161,6 +169,34 @@ namespace std _GLIBCXX_VISIBILITY(default)
return _M_mt();
}
+ double
+ random_device::_M_getentropy() const noexcept
+ {
+#if defined _GLIBCXX_HAVE_SYS_IOCTL_H && \
+ defined _GLIBCXX_HAVE_LINUX_RANDOM_H
+ if (!_M_file)
+ return 0.0;
+
+ int fd = fileno(static_cast<FILE *>(_M_file));
+ if (fd < 0)
+ return 0.0;
+
+ int ent;
+ if (ioctl(fd, RNDGETENTCNT, &ent) < 0)
+ return 0.0;
+
+ if (ent < 0)
+ return 0.0;
+
+ if (static_cast<unsigned>(ent) > sizeof(result_type) * 8)
+ return static_cast<double>(sizeof(result_type) * 8);
+
+ return static_cast<double>(ent);
+#else
+ return 0.0;
+#endif
+ }
+
template class mersenne_twister_engine<
uint_fast32_t,
32, 624, 397, 31,
--
2.7.1
--
Xi Ruoyao <r...@stu.xidian.edu.cn>
School of Aerospace Science and Technology, Xidian University
