Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 95 insertions, 0 deletions

diff --git a/vdso/vdso.cc b/vdso/vdso.cc
new file mode 100644
index 000000000..db3bdef01
--- /dev/null
+++ b/vdso/vdso.cc
@@ -0,0 +1,95 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// This is the VDSO for sandboxed binaries. This file just contains the entry
+// points to the VDSO. All of the real work is done in vdso_time.cc
+
+#define _DEFAULT_SOURCE  // ensure glibc provides struct timezone.
+#include <sys/time.h>
+#include <time.h>
+
+#include "vdso/syscalls.h"
+#include "vdso/vdso_time.h"
+
+namespace vdso {
+
+// __vdso_clock_gettime() implements clock_gettime()
+extern "C" int __vdso_clock_gettime(clockid_t clock, struct timespec* ts) {
+  int ret;
+
+  switch (clock) {
+    case CLOCK_REALTIME:
+      ret = ClockRealtime(ts);
+      break;
+
+    case CLOCK_MONOTONIC:
+      ret = ClockMonotonic(ts);
+      break;
+
+    default:
+      ret = sys_clock_gettime(clock, ts);
+      break;
+  }
+
+  return ret;
+}
+extern "C" int clock_gettime(clockid_t clock, struct timespec* ts)
+    __attribute__((weak, alias("__vdso_clock_gettime")));
+
+// __vdso_gettimeofday() implements gettimeofday()
+extern "C" int __vdso_gettimeofday(struct timeval* tv, struct timezone* tz) {
+  if (tv) {
+    struct timespec ts;
+    int ret = ClockRealtime(&ts);
+    if (ret) {
+      return ret;
+    }
+    tv->tv_sec = ts.tv_sec;
+    tv->tv_usec = ts.tv_nsec / 1000;
+  }
+
+  // Nobody should be calling gettimeofday() with a non-NULL
+  // timezone pointer. If they do then they will get zeros.
+  if (tz) {
+    tz->tz_minuteswest = 0;
+    tz->tz_dsttime = 0;
+  }
+
+  return 0;
+}
+extern "C" int gettimeofday(struct timeval* tv, struct timezone* tz)
+    __attribute__((weak, alias("__vdso_gettimeofday")));
+
+// __vdso_time() implements time()
+extern "C" time_t __vdso_time(time_t* t) {
+  struct timespec ts;
+  ClockRealtime(&ts);
+  if (t) {
+    *t = ts.tv_sec;
+  }
+  return ts.tv_sec;
+}
+extern "C" time_t time(time_t* t) __attribute__((weak, alias("__vdso_time")));
+
+// __vdso_getcpu() implements getcpu()
+extern "C" long __vdso_getcpu(unsigned* cpu, unsigned* node,
+                              struct getcpu_cache* cache) {
+  // No optimizations yet, just make the real system call.
+  return sys_getcpu(cpu, node, cache);
+}
+extern "C" long getcpu(unsigned* cpu, unsigned* node,
+                       struct getcpu_cache* cache)
+    __attribute__((weak, alias("__vdso_getcpu")));
+
+}  // namespace vdso