wasi: Support sharing envvar to container

Signed-off-by: Kohei Tokunaga <[email protected]>

cmd/init/main.go

@@ -273,6 +273,8 @@ func patchSpec(s runtimespec.Spec, infoD []byte, imageConfig imagespec.Image) ru
 			args = append(args, strings.ReplaceAll(string(o[prev:]), "\\ ", " "))
 		case "e":
 			entrypoint = []string{o}
+		case "env":
+			s.Process.Env = append(s.Process.Env, o)
 		default:
 			log.Printf("unsupported prefix: %q", inst)
 		}

patches/bochs/Bochs/bochs/main.cc

@@ -40,6 +40,7 @@
 
 #ifdef WASI
 #include <wizer.h>
+#include <wasi/libc-environ.h>
 extern "C" {
 #include "jmp.h"
 }
@@ -382,6 +383,34 @@ int write_args(FSVirtFile *f, int argc, char **argv, int optind, int pos1)
   return pos - pos1;
 }
 
+int write_env(FSVirtFile *f, int pos1, const char *env)
+{
+  int p, pos = pos1;
+
+  p = write_info(f, pos, 5, "env: ");
+  if (p < 0) {
+    return -1;
+  }
+  pos += p;
+  for (int j = 0; j < strlen(env); j++) {
+    if (env[j] == '\n') {
+      p = write_info(f, pos, 2, "\\\n");
+      if (p != 2) {
+        return -1;
+      }
+      pos += p;
+      continue;
+    }
+    if (putchar_info(f, pos++, env[j]) != 1) {
+      return -1;
+    }
+  }
+  if (putchar_info(f, pos++, '\n') != 1) {
+    return -1;
+  }
+  return pos - pos1;
+}
+
 static struct option options[] = {
     { "help", no_argument, NULL, 'h' },
     { "no-stdin", no_argument },
@@ -465,6 +494,19 @@ int init_wasi_info(int argc, char **argv, FSVirtFile *info)
       pos += p;
     }
 
+#ifdef WASI
+    // TODO: support emscripten; it seems some default variables are passed, which shouldn't be inherited by the container.
+    // https://github.com/emscripten-core/emscripten/blob/0566a76b500bd2bbd535e108f657fce1db7f6f75/src/library_wasi.js#L62
+    for (char **env = environ; *env; ++env) {
+      int p = write_env(info, pos, *env);
+      if (p < 0) {
+        printf("failed to prepare env info\n");
+        exit(1);
+      }
+      pos += p;
+    }
+#endif
+
     info->len = pos;
 #ifdef WASI
     info->len += write_preopen_info(info, pos);
@@ -752,6 +794,7 @@ int CDECL start_vm(void)
 int CDECL main(int argc, char *argv[])
 {
 #ifdef WASI
+  __wasilibc_ensure_environ();
   __wasi_vfs_rt_init();
   if (populate_preopens() != 0) { // register wasi-vfs dir to wasi-libc and our list
     fprintf(stderr, "failed to populate preopens");

patches/tinyemu/tinyemu/temu.c

@@ -58,6 +58,8 @@
 #include "wasi.h"
 #endif
 
+extern char **environ;
+
 #ifdef ON_BROWSER
 #include <emscripten.h>
 #endif
@@ -918,6 +920,34 @@ int write_args(FSVirtFile *f, int argc, char **argv, int optind, int pos1)
   return pos - pos1;
 }
 
+int write_env(FSVirtFile *f, int pos1, const char *env)
+{
+  int p, pos = pos1;
+
+  p = write_info(f, pos, 5, "env: ");
+  if (p < 0) {
+    return -1;
+  }
+  pos += p;
+  for (int j = 0; j < strlen(env); j++) {
+    if (env[j] == '\n') {
+      p = write_info(f, pos, 2, "\\\n");
+      if (p != 2) {
+        return -1;
+      }
+      pos += p;
+      continue;
+    }
+    if (putchar_info(f, pos++, env[j]) != 1) {
+      return -1;
+    }
+  }
+  if (putchar_info(f, pos++, '\n') != 1) {
+    return -1;
+  }
+  return pos - pos1;
+}
+
 int main(int argc, char **argv)
 {
 #ifdef WASI
@@ -984,6 +1014,19 @@ int main(int argc, char **argv)
       pos += p;
     }
 
+#ifdef WASI
+    // TODO: support emscripten; it seems some default variables are passed, which shouldn't be inherited by the container.
+    // https://github.com/emscripten-core/emscripten/blob/0566a76b500bd2bbd535e108f657fce1db7f6f75/src/library_wasi.js#L62
+    for (char **env = environ; *env; ++env) {
+      int p = write_env(info, pos, *env);
+      if (p < 0) {
+        printf("failed to prepare env info\n");
+        exit(1);
+      }
+      pos += p;
+    }
+#endif
+
     info->len = pos;
 #ifdef WASI
     info->len += write_preopen_info(info, pos);

patches/tinyemu/tinyemu/wasi.c

@@ -26,6 +26,7 @@
 #include <string.h>
 
 #include <wasi/libc.h>
+#include <wasi/libc-environ.h>
 
 #include "cutils.h"
 #include "fs.h"
@@ -160,6 +161,7 @@ extern void __wasi_vfs_rt_init(void);
 
 int init_wasi()
 {
+    __wasilibc_ensure_environ();
     __wasi_vfs_rt_init(); // initialize wasi-vfs
     if (populate_preopens() != 0) { // register mapdir and wasi-vfs dir to wasi-libc and our list
       fprintf(stderr, "failed to populate preopens");

tests/integration/wamr_test.go

@@ -127,5 +127,20 @@ func TestWamr(t *testing.T) {
 				},
 			),
 		},
+		{
+			Name:    "wamr-env",
+			Runtime: "iwasm",
+			Inputs: []utils.Input{
+				{Image: "alpine:3.17", Architecture: utils.X86_64},
+				{Image: "riscv64/alpine:20221110", ConvertOpts: []string{"--target-arch=riscv64"}, Architecture: utils.RISCV64},
+			},
+			ImageName: "test2.wasm",
+			Prepare: func(t *testing.T, workdir string) {
+				assert.NilError(t, exec.Command("wamrc", "-o", filepath.Join(workdir, "test2.wasm"), filepath.Join(workdir, "test.wasm")).Run())
+			},
+			RuntimeOpts: utils.StringFlags("--env=AAA=hello", "--env=BBB=world"),
+			Args:        utils.StringFlags("/bin/sh", "-c", "echo -n $AAA $BBB"),
+			Want:        utils.WantString("hello world"),
+		},
 	}...)
 }

tests/integration/wasmedge_test.go

@@ -55,5 +55,20 @@ func TestWasmedge(t *testing.T) {
 			Args: utils.StringFlags("--no-stdin", "cat", "/map/dir/hi"),
 			Want: utils.WantString("teststring"),
 		},
+		{
+			Name:    "wasmedge-env",
+			Runtime: "wasmedge",
+			Inputs: []utils.Input{
+				{Image: "alpine:3.17", Architecture: utils.X86_64},
+				{Image: "riscv64/alpine:20221110", ConvertOpts: []string{"--target-arch=riscv64"}, Architecture: utils.RISCV64},
+			},
+			ImageName: "test2.wasm",
+			Prepare: func(t *testing.T, workdir string) {
+				assert.NilError(t, exec.Command("wasmedgec", filepath.Join(workdir, "test.wasm"), filepath.Join(workdir, "test2.wasm")).Run())
+			},
+			RuntimeOpts: utils.StringFlags("--env=AAA=hello", "--env=BBB=world"),
+			Args:        utils.StringFlags("--no-stdin", "/bin/sh", "-c", "echo -n $AAA $BBB"), // NOTE: stdin unsupported on wasmedge as of now
+			Want:        utils.WantString("hello world"),
+		},
 	}...)
 }

tests/integration/wasmer_test.go

@@ -47,5 +47,16 @@ func TestWasmer(t *testing.T) {
 			Args: utils.StringFlags("--", "--no-stdin", "cat", "/mapped/dir/test/hi"),
 			Want: utils.WantString("teststring"),
 		},
+		{
+			Name:    "wasmer-env",
+			Runtime: "wasmer",
+			Inputs: []utils.Input{
+				{Image: "alpine:3.17", Architecture: utils.X86_64},
+				{Image: "riscv64/alpine:20221110", ConvertOpts: []string{"--target-arch=riscv64"}, Architecture: utils.RISCV64},
+			},
+			RuntimeOpts: utils.StringFlags("--env=AAA=hello", "--env=BBB=world"),
+			Args:        utils.StringFlags("--", "--no-stdin", "/bin/sh", "-c", "echo -n $AAA $BBB"), // wasmer requires "--" before flags we pass to the wasm program.
+			Want:        utils.WantString("hello world"),
+		},
 	}...)
 }

tests/integration/wasmtime_test.go

@@ -104,6 +104,17 @@ func TestWasmtime(t *testing.T) {
 				[2]string{"echo -n hello > /mapped/dir/test/from-guest/testhello\n", ""},
 			),
 		},
+		{
+			Name:    "wasmtime-env",
+			Runtime: "wasmtime",
+			Inputs: []utils.Input{
+				{Image: "alpine:3.17", Architecture: utils.X86_64},
+				{Image: "riscv64/alpine:20221110", ConvertOpts: []string{"--target-arch=riscv64"}, Architecture: utils.RISCV64},
+			},
+			RuntimeOpts: utils.StringFlags("--env=AAA=hello", "--env=BBB=world"),
+			Args:        utils.StringFlags("/bin/sh", "-c", "echo -n $AAA $BBB"),
+			Want:        utils.WantString("hello world"),
+		},
 		// Other architectures
 		{
 			Name:       "wasmtime-hello-arch-aarch64",

tests/integration/wazero_test.go

@@ -106,5 +106,16 @@ func TestWazero(t *testing.T) {
 				[2]string{"echo -n hello > /mapdir/from-guest/testhello\n", ""},
 			),
 		},
+		{
+			Name:    "wazero-env",
+			Runtime: "wazero-test",
+			Inputs: []utils.Input{
+				{Image: "alpine:3.17", Architecture: utils.X86_64},
+				{Image: "riscv64/alpine:20221110", ConvertOpts: []string{"--target-arch=riscv64"}, Architecture: utils.RISCV64},
+			},
+			RuntimeOpts: utils.StringFlags("--env=AAA=hello", "--env=BBB=world"),
+			Args:        utils.StringFlags("/bin/sh", "-c", "echo -n $AAA $BBB"),
+			Want:        utils.WantString("hello world"),
+		},
 	}...)
 }

tests/wazero/main.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	crand "crypto/rand"
 	"flag"
+	"fmt"
 	"os"
 	"strings"
 
@@ -15,6 +16,8 @@ func main() {
 	var (
 		mapDir = flag.String("mapdir", "", "directory mapping to the image")
 	)
+	var envs envFlags
+	flag.Var(&envs, "env", "environment variables")
 
 	flag.Parse()
 	args := flag.Args()
@@ -41,11 +44,28 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
-	// we forcibly enable non-blocking read of stdin.
-	_, err = r.InstantiateModule(ctx, compiled,
-		wazero.NewModuleConfig().WithSysWalltime().WithSysNanotime().WithSysNanosleep().WithRandSource(crand.Reader).WithStdout(os.Stdout).WithStderr(os.Stderr).WithStdin(os.Stdin).WithFSConfig(fsConfig).WithArgs(append([]string{"arg0"}, args[1:]...)...))
+	conf := wazero.NewModuleConfig().WithSysWalltime().WithSysNanotime().WithSysNanosleep().WithRandSource(crand.Reader).WithStdout(os.Stdout).WithStderr(os.Stderr).WithStdin(os.Stdin).WithFSConfig(fsConfig).WithArgs(append([]string{"arg0"}, args[1:]...)...)
+	for _, v := range envs {
+		es := strings.SplitN(v, "=", 2)
+		if len(es) == 2 {
+			conf = conf.WithEnv(es[0], es[1])
+		} else {
+			panic("env must be a key value pair")
+		}
+	}
+	_, err = r.InstantiateModule(ctx, compiled, conf)
 	if err != nil {
 		panic(err)
 	}
 	return
 }
+
+type envFlags []string
+
+func (i *envFlags) String() string {
+	return fmt.Sprintf("%v", []string(*i))
+}
+func (i *envFlags) Set(value string) error {
+	*i = append(*i, value)
+	return nil
+}