Add arc4random support to the kernel.

kernel/include/sortix/kernel/random.h

@@ -0,0 +1,39 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+    This file is part of Sortix.
+
+    Sortix is free software: you can redistribute it and/or modify it under the
+    terms of the GNU General Public License as published by the Free Software
+    Foundation, either version 3 of the License, or (at your option) any later
+    version.
+
+    Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+    details.
+
+    You should have received a copy of the GNU General Public License along with
+    Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+    sortix/kernel/random.h
+    Kernel entropy gathering.
+
+*******************************************************************************/
+
+#ifndef INCLUDE_SORTIX_KERNEL_RANDOM_H
+#define INCLUDE_SORTIX_KERNEL_RANDOM_H
+
+#include <stddef.h>
+
+namespace Sortix {
+namespace Random {
+
+bool HasEntropy();
+void GetEntropy(void* buffer, size_t size);
+
+} // namespace Random
+} // namespace Sortix
+
+#endif

kernel/random.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2014.
+    Copyright(C) Jonas 'Sortie' Termansen 2014, 2015.
 
     This file is part of Sortix.
 
@@ -23,6 +23,8 @@
 *******************************************************************************/
 
 #include <errno.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include <sortix/clock.h>
 
@@ -32,10 +34,17 @@
 #include <sortix/kernel/time.h>
 
 namespace Sortix {
+namespace Random {
 
 static unsigned long sequence = 0;
 
-int sys_getentropy(void* user_buffer, size_t size)
+bool HasEntropy()
+{
+	// We only have new entropy once and that's at boot.
+	return sequence == 0;
+}
+
+void GetEntropy(void* result, size_t size)
 {
 	union
 	{
@@ -48,7 +57,7 @@ int sys_getentropy(void* user_buffer, size_t size)
 		} seed;
 	};
 	if ( sizeof(buffer) < size )
-		return errno = EIO, -1;
+		size = sizeof(buffer);
 	// TODO: SECURITY: We need to actually gather entropy and deliver it.
 	for ( size_t i = 0; i < size; i++ )
 		buffer[i] = i;
@@ -60,6 +69,20 @@ int sys_getentropy(void* user_buffer, size_t size)
 	seed.realtime = Time::Get(CLOCK_REALTIME);
 	seed.monotonic = Time::Get(CLOCK_MONOTONIC);
 	seed.sequence = InterlockedIncrement(&sequence).o;
+	memcpy(result, buffer, size);
+}
+
+} // namespace Random
+} // namespace Sortix
+
+namespace Sortix {
+
+int sys_getentropy(void* user_buffer, size_t size)
+{
+	unsigned char buffer[256];
+	if ( sizeof(buffer) < size )
+		return errno = EIO, -1;
+	arc4random_buf(buffer, sizeof(buffer));
 	if ( !CopyToUser(user_buffer, buffer, size) )
 		return -1;
 	return 0;

libc/Makefile

@@ -153,6 +153,9 @@ stdio/vsprintf.o \
 stdio/vsscanf.o \
 stdlib/abort.o \
 stdlib/abs.o \
+stdlib/arc4random_buf.o \
+stdlib/arc4random.o \
+stdlib/arc4random_uniform.o \
 stdlib/atof.o \
 stdlib/atoi.o \
 stdlib/atoll.o \
@@ -432,9 +435,6 @@ stdio/tmpfile.o \
 stdio/vfprintf.o \
 stdio/vprintf.o \
 stdio/vscanf.o \
-stdlib/arc4random_buf.o \
-stdlib/arc4random.o \
-stdlib/arc4random_uniform.o \
 stdlib/atexit.o \
 stdlib/canonicalize_file_name_at.o \
 stdlib/canonicalize_file_name.o \

libc/stdlib/arc4random_buf.cpp

@@ -26,16 +26,32 @@
  * Public domain.
  */
 
-/* Adapted for Sortix libc by Jonas 'Sortie' Termansen in 2014. */
+/* Adapted for Sortix libc by Jonas 'Sortie' Termansen in 2014, 2015. */
 
 #include <assert.h>
 #include <endian.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#if !defined(__is_sortix_kernel)
 #include <pthread.h>
+#endif
 #include <unistd.h>
 
+#if defined(__is_sortix_kernel)
+#include <sortix/kernel/kthread.h>
+#include <sortix/kernel/random.h>
+#endif
+
+#if defined(__is_sortix_kernel)
+#define PTHREAD_MUTEX_INITIALIZER Sortix::KTHREAD_MUTEX_INITIALIZER
+#define pthread_mutex_t Sortix::kthread_mutex_t
+#define pthread_mutex_lock Sortix::kthread_mutex_lock
+#define pthread_mutex_unlock Sortix::kthread_mutex_unlock
+#define getpid() 0
+#define getentropy Sortix::Random::GetEntropy
+#endif
+
 struct chacha
 {
 	uint32_t input[16];
@@ -163,6 +179,15 @@ extern "C" void arc4random_buf(void* buffer_ptr, size_t size)
 
 	pthread_mutex_lock(&arc4random_mutex);
 
+#if defined(__is_sortix_kernel)
+	if ( Sortix::Random::HasEntropy() )
+	{
+		rs_count = 0;
+		rs_have = 0;
+		memset(rs_buf, 0, sizeof(rs_buf));
+	}
+#endif
+
 	/* TODO: Employ zero-memory-on-fork semantics instead. */
 	/* pid_t are never reused on Sortix at the moment. */
 	if ( getpid() != rs_pid )