Enable runsc/fsgofer support on arm64.

newfstatat() syscall is not supported on arm64, so we resort
to use the fstatat() syscall.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: I9e89d46c5ec9ae07db201c9da5b6dda9bfd2eaf0

8 files changed, 163 insertions, 31 deletions

diff --git a/runsc/fsgofer/BUILD b/runsc/fsgofer/BUILD
index 80a4aa2fe..afcb41801 100644
--- a/runsc/fsgofer/BUILD
+++ b/runsc/fsgofer/BUILD
@@ -6,6 +6,8 @@ go_library(
     name = "fsgofer",
     srcs = [
         "fsgofer.go",
+        "fsgofer_amd64_unsafe.go",
+        "fsgofer_arm64_unsafe.go",
         "fsgofer_unsafe.go",
     ],
     importpath = "gvisor.dev/gvisor/runsc/fsgofer",
diff --git a/runsc/fsgofer/filter/BUILD b/runsc/fsgofer/filter/BUILD
index 02168ad1b..bac73f89d 100644
--- a/runsc/fsgofer/filter/BUILD
+++ b/runsc/fsgofer/filter/BUILD
@@ -6,6 +6,8 @@ go_library(
     name = "filter",
     srcs = [
         "config.go",
+        "config_amd64.go",
+        "config_arm64.go",
         "extra_filters.go",
         "extra_filters_msan.go",
         "extra_filters_race.go",
diff --git a/runsc/fsgofer/filter/config.go b/runsc/fsgofer/filter/config.go
index 2ea95f8fb..a1792330f 100644
--- a/runsc/fsgofer/filter/config.go
+++ b/runsc/fsgofer/filter/config.go
@@ -25,11 +25,7 @@ import (
 
 // allowedSyscalls is the set of syscalls executed by the gofer.
 var allowedSyscalls = seccomp.SyscallRules{
-	syscall.SYS_ACCEPT: {},
-	syscall.SYS_ARCH_PRCTL: []seccomp.Rule{
-		{seccomp.AllowValue(linux.ARCH_GET_FS)},
-		{seccomp.AllowValue(linux.ARCH_SET_FS)},
-	},
+	syscall.SYS_ACCEPT:        {},
 	syscall.SYS_CLOCK_GETTIME: {},
 	syscall.SYS_CLONE: []seccomp.Rule{
 		{
@@ -155,7 +151,6 @@ var allowedSyscalls = seccomp.SyscallRules{
 	syscall.SYS_MPROTECT:   {},
 	syscall.SYS_MUNMAP:     {},
 	syscall.SYS_NANOSLEEP:  {},
-	syscall.SYS_NEWFSTATAT: {},
 	syscall.SYS_OPENAT:     {},
 	syscall.SYS_PPOLL:      {},
 	syscall.SYS_PREAD64:    {},
diff --git a/runsc/fsgofer/filter/config_amd64.go b/runsc/fsgofer/filter/config_amd64.go
new file mode 100644
index 000000000..a4b28cb8b
--- /dev/null
+++ b/runsc/fsgofer/filter/config_amd64.go
@@ -0,0 +1,33 @@
+// 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.
+
+// +build amd64
+
+package filter
+
+import (
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/seccomp"
+)
+
+func init() {
+	allowedSyscalls[syscall.SYS_ARCH_PRCTL] = []seccomp.Rule{
+		{seccomp.AllowValue(linux.ARCH_GET_FS)},
+		{seccomp.AllowValue(linux.ARCH_SET_FS)},
+	}
+
+	allowedSyscalls[syscall.SYS_NEWFSTATAT] = []seccomp.Rule{}
+}
diff --git a/runsc/fsgofer/filter/config_arm64.go b/runsc/fsgofer/filter/config_arm64.go
new file mode 100644
index 000000000..d2697deb7
--- /dev/null
+++ b/runsc/fsgofer/filter/config_arm64.go
@@ -0,0 +1,27 @@
+// 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.
+
+// +build arm64
+
+package filter
+
+import (
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/seccomp"
+)
+
+func init() {
+	allowedSyscalls[syscall.SYS_FSTATAT] = []seccomp.Rule{}
+}
diff --git a/runsc/fsgofer/fsgofer_amd64_unsafe.go b/runsc/fsgofer/fsgofer_amd64_unsafe.go
new file mode 100644
index 000000000..5d4aab597
--- /dev/null
+++ b/runsc/fsgofer/fsgofer_amd64_unsafe.go
@@ -0,0 +1,49 @@
+// 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.
+
+// +build amd64
+
+package fsgofer
+
+import (
+	"syscall"
+	"unsafe"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/syserr"
+)
+
+func statAt(dirFd int, name string) (syscall.Stat_t, error) {
+	nameBytes, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return syscall.Stat_t{}, err
+	}
+	namePtr := unsafe.Pointer(nameBytes)
+
+	var stat syscall.Stat_t
+	statPtr := unsafe.Pointer(&stat)
+
+	if _, _, errno := syscall.Syscall6(
+		syscall.SYS_NEWFSTATAT,
+		uintptr(dirFd),
+		uintptr(namePtr),
+		uintptr(statPtr),
+		linux.AT_SYMLINK_NOFOLLOW,
+		0,
+		0); errno != 0 {
+
+		return syscall.Stat_t{}, syserr.FromHost(errno).ToError()
+	}
+	return stat, nil
+}
diff --git a/runsc/fsgofer/fsgofer_arm64_unsafe.go b/runsc/fsgofer/fsgofer_arm64_unsafe.go
new file mode 100644
index 000000000..8041fd352
--- /dev/null
+++ b/runsc/fsgofer/fsgofer_arm64_unsafe.go
@@ -0,0 +1,49 @@
+// 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.
+
+// +build arm64
+
+package fsgofer
+
+import (
+	"syscall"
+	"unsafe"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/syserr"
+)
+
+func statAt(dirFd int, name string) (syscall.Stat_t, error) {
+	nameBytes, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return syscall.Stat_t{}, err
+	}
+	namePtr := unsafe.Pointer(nameBytes)
+
+	var stat syscall.Stat_t
+	statPtr := unsafe.Pointer(&stat)
+
+	if _, _, errno := syscall.Syscall6(
+		syscall.SYS_FSTATAT,
+		uintptr(dirFd),
+		uintptr(namePtr),
+		uintptr(statPtr),
+		linux.AT_SYMLINK_NOFOLLOW,
+		0,
+		0); errno != 0 {
+
+		return syscall.Stat_t{}, syserr.FromHost(errno).ToError()
+	}
+	return stat, nil
+}
diff --git a/runsc/fsgofer/fsgofer_unsafe.go b/runsc/fsgofer/fsgofer_unsafe.go
index ff2556aee..542b54365 100644
--- a/runsc/fsgofer/fsgofer_unsafe.go
+++ b/runsc/fsgofer/fsgofer_unsafe.go
@@ -18,34 +18,9 @@ import (
 	"syscall"
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/syserr"
 )
 
-func statAt(dirFd int, name string) (syscall.Stat_t, error) {
-	nameBytes, err := syscall.BytePtrFromString(name)
-	if err != nil {
-		return syscall.Stat_t{}, err
-	}
-	namePtr := unsafe.Pointer(nameBytes)
-
-	var stat syscall.Stat_t
-	statPtr := unsafe.Pointer(&stat)
-
-	if _, _, errno := syscall.Syscall6(
-		syscall.SYS_NEWFSTATAT,
-		uintptr(dirFd),
-		uintptr(namePtr),
-		uintptr(statPtr),
-		linux.AT_SYMLINK_NOFOLLOW,
-		0,
-		0); errno != 0 {
-
-		return syscall.Stat_t{}, syserr.FromHost(errno).ToError()
-	}
-	return stat, nil
-}
-
 func utimensat(dirFd int, name string, times [2]syscall.Timespec, flags int) error {
 	// utimensat(2) doesn't accept empty name, instead name must be nil to make it
 	// operate directly on 'dirFd' unlike other *at syscalls.