1 files changed, 68 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/proc/version.go b/pkg/sentry/fsimpl/proc/version.go
new file mode 100644
index 000000000..e1643d4e0
--- /dev/null
+++ b/pkg/sentry/fsimpl/proc/version.go
@@ -0,0 +1,68 @@
+// Copyright 2019 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 proc
+
+import (
+	"bytes"
+	"fmt"
+
+	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+// versionData implements vfs.DynamicBytesSource for /proc/version.
+//
+// +stateify savable
+type versionData struct {
+	// k is the owning Kernel.
+	k *kernel.Kernel
+}
+
+var _ vfs.DynamicBytesSource = (*versionData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (v *versionData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	init := v.k.GlobalInit()
+	if init == nil {
+		// Attempted to read before the init Task is created. This can
+		// only occur during startup, which should never need to read
+		// this file.
+		panic("Attempted to read version before initial Task is available")
+	}
+
+	// /proc/version takes the form:
+	//
+	// "SYSNAME version RELEASE (COMPILE_USER@COMPILE_HOST)
+	// (COMPILER_VERSION) VERSION"
+	//
+	// where:
+	// - SYSNAME, RELEASE, and VERSION are the same as returned by
+	// sys_utsname
+	// - COMPILE_USER is the user that build the kernel
+	// - COMPILE_HOST is the hostname of the machine on which the kernel
+	// was built
+	// - COMPILER_VERSION is the version reported by the building compiler
+	//
+	// Since we don't really want to expose build information to
+	// applications, those fields are omitted.
+	//
+	// FIXME(mpratt): Using Version from the init task SyscallTable
+	// disregards the different version a task may have (e.g., in a uts
+	// namespace).
+	ver := init.Leader().SyscallTable().Version
+	fmt.Fprintf(buf, "%s version %s %s\n", ver.Sysname, ver.Release, ver.Version)
+	return nil
+}