Avoid importing platforms from many source files

PiperOrigin-RevId: 256494243

18 files changed, 82 insertions, 108 deletions

diff --git a/runsc/BUILD b/runsc/BUILD
index 0e4cf8e09..6b8c92706 100644
--- a/runsc/BUILD
+++ b/runsc/BUILD
@@ -16,6 +16,7 @@ go_binary(
     x_defs = {"main.version": "{VERSION}"},
     deps = [
         "//pkg/log",
+        "//pkg/sentry/platform",
         "//runsc/boot",
         "//runsc/cmd",
         "//runsc/specutils",
@@ -47,6 +48,7 @@ go_binary(
     x_defs = {"main.version": "{VERSION}"},
     deps = [
         "//pkg/log",
+        "//pkg/sentry/platform",
         "//runsc/boot",
         "//runsc/cmd",
         "//runsc/specutils",
diff --git a/runsc/boot/BUILD b/runsc/boot/BUILD
index 16cd6540f..5025401dd 100644
--- a/runsc/boot/BUILD
+++ b/runsc/boot/BUILD
@@ -56,8 +56,6 @@ go_library(
         "//pkg/sentry/loader",
         "//pkg/sentry/pgalloc",
         "//pkg/sentry/platform",
-        "//pkg/sentry/platform/kvm",
-        "//pkg/sentry/platform/ptrace",
         "//pkg/sentry/sighandling",
         "//pkg/sentry/socket/epsocket",
         "//pkg/sentry/socket/hostinet",
@@ -86,6 +84,7 @@ go_library(
         "//pkg/tcpip/transport/udp",
         "//pkg/urpc",
         "//runsc/boot/filter",
+        "//runsc/boot/platforms",
         "//runsc/specutils",
         "@com_github_golang_protobuf//proto:go_default_library",
         "@com_github_opencontainers_runtime-spec//specs-go:go_default_library",
diff --git a/runsc/boot/config.go b/runsc/boot/config.go
index 6d276f207..6f1eb9a41 100644
--- a/runsc/boot/config.go
+++ b/runsc/boot/config.go
@@ -22,40 +22,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/watchdog"
 )
 
-// PlatformType tells which platform to use.
-type PlatformType int
-
-const (
-	// PlatformPtrace runs the sandbox with the ptrace platform.
-	PlatformPtrace PlatformType = iota
-
-	// PlatformKVM runs the sandbox with the KVM platform.
-	PlatformKVM
-)
-
-// MakePlatformType converts type from string.
-func MakePlatformType(s string) (PlatformType, error) {
-	switch s {
-	case "ptrace":
-		return PlatformPtrace, nil
-	case "kvm":
-		return PlatformKVM, nil
-	default:
-		return 0, fmt.Errorf("invalid platform type %q", s)
-	}
-}
-
-func (p PlatformType) String() string {
-	switch p {
-	case PlatformPtrace:
-		return "ptrace"
-	case PlatformKVM:
-		return "kvm"
-	default:
-		return fmt.Sprintf("unknown(%d)", p)
-	}
-}
-
 // FileAccessType tells how the filesystem is accessed.
 type FileAccessType int
 
@@ -187,7 +153,7 @@ type Config struct {
 	LogPackets bool
 
 	// Platform is the platform to run on.
-	Platform PlatformType
+	Platform string
 
 	// Strace indicates that strace should be enabled.
 	Strace bool
@@ -247,7 +213,7 @@ func (c *Config) ToFlags() []string {
 		"--overlay=" + strconv.FormatBool(c.Overlay),
 		"--network=" + c.Network.String(),
 		"--log-packets=" + strconv.FormatBool(c.LogPackets),
-		"--platform=" + c.Platform.String(),
+		"--platform=" + c.Platform,
 		"--strace=" + strconv.FormatBool(c.Strace),
 		"--strace-syscalls=" + strings.Join(c.StraceSyscalls, ","),
 		"--strace-log-size=" + strconv.Itoa(int(c.StraceLogSize)),
diff --git a/runsc/boot/filter/BUILD b/runsc/boot/filter/BUILD
index 07898f3de..f5509b6b7 100644
--- a/runsc/boot/filter/BUILD
+++ b/runsc/boot/filter/BUILD
@@ -20,8 +20,6 @@ go_library(
         "//pkg/log",
         "//pkg/seccomp",
         "//pkg/sentry/platform",
-        "//pkg/sentry/platform/kvm",
-        "//pkg/sentry/platform/ptrace",
         "//pkg/tcpip/link/fdbased",
         "@org_golang_x_sys//unix:go_default_library",
     ],
diff --git a/runsc/boot/filter/config.go b/runsc/boot/filter/config.go
index e4ccb40d9..0ee5b8bbd 100644
--- a/runsc/boot/filter/config.go
+++ b/runsc/boot/filter/config.go
@@ -437,29 +437,6 @@ func hostInetFilters() seccomp.SyscallRules {
 	}
 }
 
-// ptraceFilters returns syscalls made exclusively by the ptrace platform.
-func ptraceFilters() seccomp.SyscallRules {
-	return seccomp.SyscallRules{
-		unix.SYS_GETCPU:            {},
-		unix.SYS_SCHED_SETAFFINITY: {},
-		syscall.SYS_PTRACE:         {},
-		syscall.SYS_TGKILL:         {},
-		syscall.SYS_WAIT4:          {},
-	}
-}
-
-// kvmFilters returns syscalls made exclusively by the KVM platform.
-func kvmFilters() seccomp.SyscallRules {
-	return seccomp.SyscallRules{
-		syscall.SYS_ARCH_PRCTL:      {},
-		syscall.SYS_IOCTL:           {},
-		syscall.SYS_MMAP:            {},
-		syscall.SYS_RT_SIGSUSPEND:   {},
-		syscall.SYS_RT_SIGTIMEDWAIT: {},
-		0xffffffffffffffff:          {}, // KVM uses syscall -1 to transition to host.
-	}
-}
-
 func controlServerFilters(fd int) seccomp.SyscallRules {
 	return seccomp.SyscallRules{
 		syscall.SYS_ACCEPT: []seccomp.Rule{
diff --git a/runsc/boot/filter/filter.go b/runsc/boot/filter/filter.go
index 468481f29..e80c171b3 100644
--- a/runsc/boot/filter/filter.go
+++ b/runsc/boot/filter/filter.go
@@ -18,13 +18,9 @@
 package filter
 
 import (
-	"fmt"
-
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/seccomp"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/platform/kvm"
-	"gvisor.dev/gvisor/pkg/sentry/platform/ptrace"
 )
 
 // Options are seccomp filter related options.
@@ -53,14 +49,7 @@ func Install(opt Options) error {
 		s.Merge(profileFilters())
 	}
 
-	switch p := opt.Platform.(type) {
-	case *ptrace.PTrace:
-		s.Merge(ptraceFilters())
-	case *kvm.KVM:
-		s.Merge(kvmFilters())
-	default:
-		return fmt.Errorf("unknown platform type %T", p)
-	}
+	s.Merge(opt.Platform.SyscallFilters())
 
 	return seccomp.Install(s)
 }
diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go
index 7e27d1f49..38e426ee7 100644
--- a/runsc/boot/loader.go
+++ b/runsc/boot/loader.go
@@ -42,8 +42,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/loader"
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/platform/kvm"
-	"gvisor.dev/gvisor/pkg/sentry/platform/ptrace"
 	"gvisor.dev/gvisor/pkg/sentry/sighandling"
 	slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
 	"gvisor.dev/gvisor/pkg/sentry/time"
@@ -59,6 +57,7 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 	"gvisor.dev/gvisor/runsc/boot/filter"
+	_ "gvisor.dev/gvisor/runsc/boot/platforms" // register all platforms.
 	"gvisor.dev/gvisor/runsc/specutils"
 
 	// Include supported socket providers.
@@ -416,19 +415,12 @@ func (l *Loader) Destroy() {
 }
 
 func createPlatform(conf *Config, deviceFile *os.File) (platform.Platform, error) {
-	switch conf.Platform {
-	case PlatformPtrace:
-		log.Infof("Platform: ptrace")
-		return ptrace.New()
-	case PlatformKVM:
-		log.Infof("Platform: kvm")
-		if deviceFile == nil {
-			return nil, fmt.Errorf("kvm device file must be provided")
-		}
-		return kvm.New(deviceFile)
-	default:
-		return nil, fmt.Errorf("invalid platform %v", conf.Platform)
+	p, err := platform.Lookup(conf.Platform)
+	if err != nil {
+		panic(fmt.Sprintf("invalid platform %v: %v", conf.Platform, err))
 	}
+	log.Infof("Platform: %s", conf.Platform)
+	return p.New(deviceFile)
 }
 
 func createMemoryFile() (*pgalloc.MemoryFile, error) {
diff --git a/runsc/boot/loader_test.go b/runsc/boot/loader_test.go
index eca592e5b..ff713660d 100644
--- a/runsc/boot/loader_test.go
+++ b/runsc/boot/loader_test.go
@@ -47,6 +47,7 @@ func testConfig() *Config {
 		RootDir:        "unused_root_dir",
 		Network:        NetworkNone,
 		DisableSeccomp: true,
+		Platform:       "ptrace",
 	}
 }
 
diff --git a/runsc/boot/platforms/BUILD b/runsc/boot/platforms/BUILD
new file mode 100644
index 000000000..03391cdca
--- /dev/null
+++ b/runsc/boot/platforms/BUILD
@@ -0,0 +1,16 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "platforms",
+    srcs = ["platforms.go"],
+    importpath = "gvisor.dev/gvisor/runsc/boot/platforms",
+    visibility = [
+        "//runsc:__subpackages__",
+    ],
+    deps = [
+        "//pkg/sentry/platform/kvm",
+        "//pkg/sentry/platform/ptrace",
+    ],
+)
diff --git a/runsc/boot/platforms/platforms.go b/runsc/boot/platforms/platforms.go
new file mode 100644
index 000000000..056b46ad5
--- /dev/null
+++ b/runsc/boot/platforms/platforms.go
@@ -0,0 +1,30 @@
+// 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 platforms imports all available platform packages.
+package platforms
+
+import (
+	// Import platforms that runsc might use.
+	_ "gvisor.dev/gvisor/pkg/sentry/platform/kvm"
+	_ "gvisor.dev/gvisor/pkg/sentry/platform/ptrace"
+)
+
+const (
+	// Ptrace runs the sandbox with the ptrace platform.
+	Ptrace = "ptrace"
+
+	// KVM runs the sandbox with the KVM platform.
+	KVM = "kvm"
+)
diff --git a/runsc/cmd/BUILD b/runsc/cmd/BUILD
index 2c8b84252..5223b9972 100644
--- a/runsc/cmd/BUILD
+++ b/runsc/cmd/BUILD
@@ -46,6 +46,7 @@ go_library(
         "//pkg/unet",
         "//pkg/urpc",
         "//runsc/boot",
+        "//runsc/boot/platforms",
         "//runsc/console",
         "//runsc/container",
         "//runsc/fsgofer",
diff --git a/runsc/cmd/boot.go b/runsc/cmd/boot.go
index 272eb14d3..b40fded5b 100644
--- a/runsc/cmd/boot.go
+++ b/runsc/cmd/boot.go
@@ -26,6 +26,7 @@ import (
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/runsc/boot"
+	"gvisor.dev/gvisor/runsc/boot/platforms"
 	"gvisor.dev/gvisor/runsc/specutils"
 )
 
@@ -172,7 +173,7 @@ func (b *Boot) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 		if caps == nil {
 			caps = &specs.LinuxCapabilities{}
 		}
-		if conf.Platform == boot.PlatformPtrace {
+		if conf.Platform == platforms.Ptrace {
 			// Ptrace platform requires extra capabilities.
 			const c = "CAP_SYS_PTRACE"
 			caps.Bounding = append(caps.Bounding, c)
diff --git a/runsc/container/BUILD b/runsc/container/BUILD
index ebe77165e..e246c38ae 100644
--- a/runsc/container/BUILD
+++ b/runsc/container/BUILD
@@ -53,6 +53,7 @@ go_test(
         "//pkg/unet",
         "//pkg/urpc",
         "//runsc/boot",
+        "//runsc/boot/platforms",
         "//runsc/specutils",
         "//runsc/test/testutil",
         "@com_github_cenkalti_backoff//:go_default_library",
diff --git a/runsc/container/container_test.go b/runsc/container/container_test.go
index b09b80715..baba09fe1 100644
--- a/runsc/container/container_test.go
+++ b/runsc/container/container_test.go
@@ -36,6 +36,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/control"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/runsc/boot"
+	"gvisor.dev/gvisor/runsc/boot/platforms"
 	"gvisor.dev/gvisor/runsc/specutils"
 	"gvisor.dev/gvisor/runsc/test/testutil"
 )
@@ -256,7 +257,7 @@ func configs(opts ...configOption) []*boot.Config {
 			if testutil.RaceEnabled {
 				continue
 			}
-			c.Platform = boot.PlatformKVM
+			c.Platform = platforms.KVM
 		case nonExclusiveFS:
 			c.FileAccess = boot.FileAccessShared
 		default:
diff --git a/runsc/main.go b/runsc/main.go
index 135061cd3..bc83c57a2 100644
--- a/runsc/main.go
+++ b/runsc/main.go
@@ -30,6 +30,7 @@ import (
 
 	"github.com/google/subcommands"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/cmd"
 	"gvisor.dev/gvisor/runsc/specutils"
@@ -61,7 +62,7 @@ var (
 	straceLogSize  = flag.Uint("strace-log-size", 1024, "default size (in bytes) to log data argument blobs")
 
 	// Flags that control sandbox runtime behavior.
-	platform           = flag.String("platform", "ptrace", "specifies which platform to use: ptrace (default), kvm")
+	platformName       = flag.String("platform", "ptrace", "specifies which platform to use: ptrace (default), kvm")
 	network            = flag.String("network", "sandbox", "specifies which network to use: sandbox (default), host, none. Using network inside the sandbox is more secure because it's isolated from the host network.")
 	gso                = flag.Bool("gso", true, "enable generic segmenation offload")
 	fileAccess         = flag.String("file-access", "exclusive", "specifies which filesystem to use for the root mount: exclusive (default), shared. Volume mounts are always shared.")
@@ -139,8 +140,8 @@ func main() {
 	}
 	cmd.ErrorLogger = errorLogger
 
-	platformType, err := boot.MakePlatformType(*platform)
-	if err != nil {
+	platformType := *platformName
+	if _, err := platform.Lookup(platformType); err != nil {
 		cmd.Fatalf("%v", err)
 	}
 
diff --git a/runsc/sandbox/BUILD b/runsc/sandbox/BUILD
index f32da45c1..7fdceaab6 100644
--- a/runsc/sandbox/BUILD
+++ b/runsc/sandbox/BUILD
@@ -18,9 +18,10 @@ go_library(
         "//pkg/control/server",
         "//pkg/log",
         "//pkg/sentry/control",
-        "//pkg/sentry/platform/kvm",
+        "//pkg/sentry/platform",
         "//pkg/urpc",
         "//runsc/boot",
+        "//runsc/boot/platforms",
         "//runsc/cgroup",
         "//runsc/console",
         "//runsc/specutils",
diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go
index 6bebf0737..4a11f617d 100644
--- a/runsc/sandbox/sandbox.go
+++ b/runsc/sandbox/sandbox.go
@@ -32,9 +32,10 @@ import (
 	"gvisor.dev/gvisor/pkg/control/server"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/control"
-	"gvisor.dev/gvisor/pkg/sentry/platform/kvm"
+	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/urpc"
 	"gvisor.dev/gvisor/runsc/boot"
+	"gvisor.dev/gvisor/runsc/boot/platforms"
 	"gvisor.dev/gvisor/runsc/cgroup"
 	"gvisor.dev/gvisor/runsc/console"
 	"gvisor.dev/gvisor/runsc/specutils"
@@ -491,7 +492,7 @@ func (s *Sandbox) createSandboxProcess(conf *boot.Config, args *Args, startSyncF
 		{Type: specs.UTSNamespace},
 	}
 
-	if conf.Platform == boot.PlatformPtrace {
+	if conf.Platform == platforms.Ptrace {
 		// TODO(b/75837838): Also set a new PID namespace so that we limit
 		// access to other host processes.
 		log.Infof("Sandbox will be started in the current PID namespace")
@@ -1046,19 +1047,15 @@ func (s *Sandbox) waitForStopped() error {
 
 // deviceFileForPlatform opens the device file for the given platform. If the
 // platform does not need a device file, then nil is returned.
-func deviceFileForPlatform(p boot.PlatformType) (*os.File, error) {
-	var (
-		f   *os.File
-		err error
-	)
-	switch p {
-	case boot.PlatformKVM:
-		f, err = kvm.OpenDevice()
-	default:
-		return nil, nil
+func deviceFileForPlatform(name string) (*os.File, error) {
+	p, err := platform.Lookup(name)
+	if err != nil {
+		return nil, err
 	}
+
+	f, err := p.OpenDevice()
 	if err != nil {
 		return nil, fmt.Errorf("opening device file for platform %q: %v", p, err)
 	}
-	return f, err
+	return f, nil
 }
diff --git a/runsc/test/testutil/testutil.go b/runsc/test/testutil/testutil.go
index ecab6871d..a98675bfc 100644
--- a/runsc/test/testutil/testutil.go
+++ b/runsc/test/testutil/testutil.go
@@ -132,6 +132,7 @@ func TestConfig() *boot.Config {
 		LogPackets: true,
 		Network:    boot.NetworkNone,
 		Strace:     true,
+		Platform:   "ptrace",
 		FileAccess: boot.FileAccessExclusive,
 		TestOnlyAllowRunAsCurrentUserWithoutChroot: true,
 		NumNetworkChannels:                         1,