Merge 216da0b7 (automated)

1 files changed, 60 insertions, 0 deletions

diff --git a/pkg/sentry/platform/mmap_min_addr.go b/pkg/sentry/platform/mmap_min_addr.go
new file mode 100644
index 000000000..90976735b
--- /dev/null
+++ b/pkg/sentry/platform/mmap_min_addr.go
@@ -0,0 +1,60 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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.
+
+package platform
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strconv"
+	"strings"
+
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+)
+
+// systemMMapMinAddrSource is the source file.
+const systemMMapMinAddrSource = "/proc/sys/vm/mmap_min_addr"
+
+// systemMMapMinAddr is the system's minimum map address.
+var systemMMapMinAddr uint64
+
+// SystemMMapMinAddr returns the minimum system address.
+func SystemMMapMinAddr() usermem.Addr {
+	return usermem.Addr(systemMMapMinAddr)
+}
+
+// MMapMinAddr is a size zero struct that implements MinUserAddress based on
+// the system minimum address. It is suitable for embedding in platforms that
+// rely on the system mmap, and thus require the system minimum.
+type MMapMinAddr struct {
+}
+
+// MinUserAddress implements platform.MinUserAddresss.
+func (*MMapMinAddr) MinUserAddress() usermem.Addr {
+	return SystemMMapMinAddr()
+}
+
+func init() {
+	// Open the source file.
+	b, err := ioutil.ReadFile(systemMMapMinAddrSource)
+	if err != nil {
+		panic(fmt.Sprintf("couldn't open %s: %v", systemMMapMinAddrSource, err))
+	}
+
+	// Parse the result.
+	systemMMapMinAddr, err = strconv.ParseUint(strings.TrimSpace(string(b)), 10, 64)
+	if err != nil {
+		panic(fmt.Sprintf("couldn't parse %s from %s: %v", string(b), systemMMapMinAddrSource, err))
+	}
+}