wasip1: fix file open modes used by wasi-libc

cmd/wazero/wazero_test.go

@@ -327,8 +327,8 @@ func TestRun(t *testing.T) {
 ==> wasi_snapshot_preview1.fd_prestat_get(fd=4)
 <== (prestat=,errno=EBADF)
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=3)
-<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
-==> wasi_snapshot_preview1.path_open(fd=3,dirflags=SYMLINK_FOLLOW,path=bear.txt,oflags=,fs_rights_base=,fs_rights_inheriting=,fdflags=)
+<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=FD_DATASYNC|FDSTAT_SET_FLAGS|FD_SYNC|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK,fs_rights_inheriting=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK},errno=ESUCCESS)
+==> wasi_snapshot_preview1.path_open(fd=3,dirflags=SYMLINK_FOLLOW,path=bear.txt,oflags=,fs_rights_base=FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_ADVISE|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK|PATH_RENAME_SOURCE|PATH_RENAME_TARGET|PATH_FILESTAT_GET|PATH_FILESTAT_SET_SIZE|PATH_FILESTAT_SET_TIMES|FD_FILESTAT_GET|FD_FILESTAT_SET_TIMES|PATH_SYMLINK|PATH_REMOVE_DIRECTORY|PATH_UNLINK_FILE|POLL_FD_READWRITE,fs_rights_inheriting=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK|PATH_RENAME_SOURCE|PATH_RENAME_TARGET|PATH_FILESTAT_GET|PATH_FILESTAT_SET_SIZE|PATH_FILESTAT_SET_TIMES|FD_FILESTAT_GET|FD_FILESTAT_SET_SIZE|FD_FILESTAT_SET_TIMES|PATH_SYMLINK|PATH_REMOVE_DIRECTORY|PATH_UNLINK_FILE|POLL_FD_READWRITE,fdflags=)
 <== (opened_fd=4,errno=ESUCCESS)
 ==> wasi_snapshot_preview1.fd_filestat_get(fd=4)
 <== (filestat={filetype=REGULAR_FILE,size=5,mtim=%d},errno=ESUCCESS)

imports/wasi_snapshot_preview1/fs.go

@@ -222,24 +222,66 @@ func fdFdstatGetFn(_ context.Context, mod api.Module, params []uint64) syscall.E
 		fdflags = wasip1.FD_APPEND
 	}
 
-	filetype := getWasiFiletype(st.Mode)
-	writeFdstat(buf, filetype, fdflags)
+	var fsRightsBase uint32
+	var fsRightsInheriting uint32
+	fileType := getWasiFiletype(st.Mode)
+
+	switch fileType {
+	case wasip1.FILETYPE_DIRECTORY:
+		// To satisfy wasi-testsuite, we must advertise that directories cannot
+		// be given seek permission (RIGHT_FD_SEEK).
+		fsRightsBase = dirRightsBase
+		fsRightsInheriting = fileRightsBase | dirRightsBase
+	default:
+		fsRightsBase = fileRightsBase
+	}
 
+	writeFdstat(buf, fileType, fdflags, fsRightsBase, fsRightsInheriting)
 	return 0
 }
 
-var blockFdstat = []byte{
-	wasip1.FILETYPE_BLOCK_DEVICE, 0, // filetype
-	0, 0, 0, 0, 0, 0, // fdflags
-	0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
-	0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
-}
-
-func writeFdstat(buf []byte, filetype uint8, fdflags uint16) {
-	// memory is re-used, so ensure the result is defaulted.
-	copy(buf, blockFdstat)
-	buf[0] = filetype
-	buf[2] = byte(fdflags)
+const fileRightsBase = wasip1.RIGHT_FD_DATASYNC |
+	wasip1.RIGHT_FD_READ |
+	wasip1.RIGHT_FD_SEEK |
+	wasip1.RIGHT_FDSTAT_SET_FLAGS |
+	wasip1.RIGHT_FD_SYNC |
+	wasip1.RIGHT_FD_TELL |
+	wasip1.RIGHT_FD_WRITE |
+	wasip1.RIGHT_FD_ADVISE |
+	wasip1.RIGHT_FD_ALLOCATE |
+	wasip1.RIGHT_FD_FILESTAT_GET |
+	wasip1.RIGHT_FD_FILESTAT_SET_SIZE |
+	wasip1.RIGHT_FD_FILESTAT_SET_TIMES |
+	wasip1.RIGHT_POLL_FD_READWRITE
+
+const dirRightsBase = wasip1.RIGHT_FD_DATASYNC |
+	wasip1.RIGHT_FDSTAT_SET_FLAGS |
+	wasip1.RIGHT_FD_SYNC |
+	wasip1.RIGHT_PATH_CREATE_DIRECTORY |
+	wasip1.RIGHT_PATH_CREATE_FILE |
+	wasip1.RIGHT_PATH_LINK_SOURCE |
+	wasip1.RIGHT_PATH_LINK_TARGET |
+	wasip1.RIGHT_PATH_OPEN |
+	wasip1.RIGHT_FD_READDIR |
+	wasip1.RIGHT_PATH_READLINK |
+	wasip1.RIGHT_PATH_RENAME_SOURCE |
+	wasip1.RIGHT_PATH_RENAME_TARGET |
+	wasip1.RIGHT_PATH_FILESTAT_GET |
+	wasip1.RIGHT_PATH_FILESTAT_SET_SIZE |
+	wasip1.RIGHT_PATH_FILESTAT_SET_TIMES |
+	wasip1.RIGHT_FD_FILESTAT_GET |
+	wasip1.RIGHT_FD_FILESTAT_SET_TIMES |
+	wasip1.RIGHT_PATH_SYMLINK |
+	wasip1.RIGHT_PATH_REMOVE_DIRECTORY |
+	wasip1.RIGHT_PATH_UNLINK_FILE
+
+func writeFdstat(buf []byte, fileType uint8, fdflags uint16, fsRightsBase, fsRightsInheriting uint32) {
+	b := (*[24]byte)(buf)
+	le.PutUint16(b[0:], uint16(fileType))
+	le.PutUint16(b[2:], fdflags)
+	le.PutUint32(b[4:], 0)
+	le.PutUint64(b[8:], uint64(fsRightsBase))
+	le.PutUint64(b[16:], uint64(fsRightsInheriting))
 }
 
 // fdFdstatSetFlags is the WASI function named FdFdstatSetFlagsName which
@@ -1713,24 +1755,42 @@ func openFlags(dirflags, oflags, fdflags uint16, rights uint32) (openFlags int)
 	} else if oflags&wasip1.O_EXCL != 0 {
 		openFlags |= syscall.O_EXCL
 	}
+	// Because we don't implement rights, we paritally rely on the open flags
+	// to determine the mode in which the file will be opened. This will create
+	// divergeant behavior compared to WASI runtimes which have a more strict
+	// interpretation of the WASI capabilities model; for example, a program
+	// which sets O_CREAT but does not give read or write permissions will
+	// successfully create a file when running with wazero, but might get a
+	// permission denied error on other runtimes.
+	defaultMode := syscall.O_RDONLY
 	if oflags&wasip1.O_TRUNC != 0 {
-		openFlags |= syscall.O_RDWR | syscall.O_TRUNC
+		openFlags |= syscall.O_TRUNC
+		defaultMode = syscall.O_RDWR
 	}
 	if oflags&wasip1.O_CREAT != 0 {
-		openFlags |= syscall.O_RDWR | syscall.O_CREAT
+		openFlags |= syscall.O_CREAT
+		defaultMode = syscall.O_RDWR
 	}
 	if fdflags&wasip1.FD_APPEND != 0 {
-		openFlags |= syscall.O_RDWR | syscall.O_APPEND
+		openFlags |= syscall.O_APPEND
+		defaultMode = syscall.O_RDWR
 	}
 	// Since rights were discontinued in wasi, we only interpret RIGHT_FD_WRITE
 	// because it is the only way to know that we need to set write permissions
 	// on a file if the application did not pass any of O_CREATE, O_APPEND, nor
 	// O_TRUNC.
-	if rights&wasip1.RIGHT_FD_WRITE != 0 {
+	const r = wasip1.RIGHT_FD_READ
+	const w = wasip1.RIGHT_FD_WRITE
+	const rw = r | w
+	switch {
+	case (rights & rw) == rw:
 		openFlags |= syscall.O_RDWR
-	}
-	if openFlags == 0 {
-		openFlags = syscall.O_RDONLY
+	case (rights & w) == w:
+		openFlags |= syscall.O_WRONLY
+	case (rights & r) == r:
+		openFlags |= syscall.O_RDONLY
+	default:
+		openFlags |= defaultMode
 	}
 	return
 }

imports/wasi_snapshot_preview1/fs_test.go

@@ -248,12 +248,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				1, 0, // fs_filetype
 				0, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
+				0xff, 0x1, 0xe0, 0x8, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
 				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=0)
-<== (stat={filetype=BLOCK_DEVICE,fdflags=,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=BLOCK_DEVICE,fdflags=,fs_rights_base=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE,fs_rights_inheriting=},errno=ESUCCESS)
 `,
 		},
 		{
@@ -262,12 +262,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				1, 0, // fs_filetype
 				1, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
+				0xff, 0x1, 0xe0, 0x8, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
 				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=1)
-<== (stat={filetype=BLOCK_DEVICE,fdflags=APPEND,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=BLOCK_DEVICE,fdflags=APPEND,fs_rights_base=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE,fs_rights_inheriting=},errno=ESUCCESS)
 `,
 		},
 		{
@@ -276,12 +276,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				1, 0, // fs_filetype
 				1, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
+				0xff, 0x1, 0xe0, 0x8, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
 				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=2)
-<== (stat={filetype=BLOCK_DEVICE,fdflags=APPEND,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=BLOCK_DEVICE,fdflags=APPEND,fs_rights_base=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE,fs_rights_inheriting=},errno=ESUCCESS)
 `,
 		},
 		{
@@ -290,12 +290,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				3, 0, // fs_filetype
 				0, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
+				0x19, 0xfe, 0xbf, 0x7, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
+				0xff, 0xff, 0xff, 0xf, 0x0, 0x0, 0x0, 0x0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=3)
-<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=FD_DATASYNC|FDSTAT_SET_FLAGS|FD_SYNC|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK,fs_rights_inheriting=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK},errno=ESUCCESS)
 `,
 		},
 		{
@@ -304,12 +304,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				4, 0, // fs_filetype
 				0, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
+				0xff, 0x1, 0xe0, 0x8, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
 				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=4)
-<== (stat={filetype=REGULAR_FILE,fdflags=,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=REGULAR_FILE,fdflags=,fs_rights_base=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE,fs_rights_inheriting=},errno=ESUCCESS)
 `,
 		},
 		{
@@ -318,12 +318,12 @@ func Test_fdFdstatGet(t *testing.T) {
 			expectedMemory: []byte{
 				3, 0, // fs_filetype
 				0, 0, 0, 0, 0, 0, // fs_flags
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_base
-				0, 0, 0, 0, 0, 0, 0, 0, // fs_rights_inheriting
+				0x19, 0xfe, 0xbf, 0x7, 0x0, 0x0, 0x0, 0x0, // fs_rights_base
+				0xff, 0xff, 0xff, 0xf, 0x0, 0x0, 0x0, 0x0, // fs_rights_inheriting
 			},
 			expectedLog: `
 ==> wasi_snapshot_preview1.fd_fdstat_get(fd=5)
-<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=,fs_rights_inheriting=},errno=ESUCCESS)
+<== (stat={filetype=DIRECTORY,fdflags=,fs_rights_base=FD_DATASYNC|FDSTAT_SET_FLAGS|FD_SYNC|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK,fs_rights_inheriting=FD_DATASYNC|FD_READ|FD_SEEK|FDSTAT_SET_FLAGS|FD_SYNC|FD_TELL|FD_WRITE|FD_ADVISE|FD_ALLOCATE|PATH_CREATE_DIRECTORY|PATH_CREATE_FILE|PATH_LINK_SOURCE|PATH_LINK_TARGET|PATH_OPEN|FD_READDIR|PATH_READLINK},errno=ESUCCESS)
 `,
 		},
 		{
@@ -3936,16 +3936,16 @@ func Test_pathOpen(t *testing.T) {
 `,
 		},
 		{
-			name:   "sysfs.DirFS RIGHT_FD_WRITE",
+			name:   "sysfs.DirFS RIGHT_FD_READ|RIGHT_FD_WRITE",
 			fs:     writeFS,
 			path:   func(*testing.T) string { return fileName },
 			oflags: 0,
-			rights: wasip1.RIGHT_FD_WRITE,
+			rights: wasip1.RIGHT_FD_READ | wasip1.RIGHT_FD_WRITE,
 			expected: func(t *testing.T, fsc *sys.FSContext) {
 				requireContents(t, fsc, expectedOpenedFd, fileName, fileContents)
 			},
 			expectedLog: `
-==> wasi_snapshot_preview1.path_open(fd=3,dirflags=,path=file,oflags=,fs_rights_base=FD_WRITE,fs_rights_inheriting=,fdflags=)
+==> wasi_snapshot_preview1.path_open(fd=3,dirflags=,path=file,oflags=,fs_rights_base=FD_READ|FD_WRITE,fs_rights_inheriting=,fdflags=)
 <== (opened_fd=4,errno=ESUCCESS)
 `,
 		},

imports/wasi_snapshot_preview1/fs_unit_test.go

@@ -413,9 +413,19 @@ func Test_openFlags(t *testing.T) {
 			dirflags:          wasip1.LOOKUP_SYMLINK_FOLLOW,
 			expectedOpenFlags: syscall.O_RDONLY,
 		},
+		{
+			name:              "rights=FD_READ",
+			rights:            wasip1.RIGHT_FD_READ,
+			expectedOpenFlags: platform.O_NOFOLLOW | syscall.O_RDONLY,
+		},
 		{
 			name:              "rights=FD_WRITE",
 			rights:            wasip1.RIGHT_FD_WRITE,
+			expectedOpenFlags: platform.O_NOFOLLOW | syscall.O_WRONLY,
+		},
+		{
+			name:              "rights=FD_READ|FD_WRITE",
+			rights:            wasip1.RIGHT_FD_READ | wasip1.RIGHT_FD_WRITE,
 			expectedOpenFlags: platform.O_NOFOLLOW | syscall.O_RDWR,
 		},
 	}

imports/wasi_snapshot_preview1/testdata/zig-cc/wasi.c

@@ -1,5 +1,6 @@
 #include <dirent.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
@@ -70,6 +71,54 @@ void main_sleepmillis(int millis) {
    printf("OK\n");
 }
 
+void main_open_rdonly() {
+  const char *path = "zig-cc.rdonly.test";
+  int fd;
+  char buf[32];
+
+  fd = open(path, O_CREAT|O_TRUNC|O_RDONLY, 0644);
+  if (fd < 0) {
+    perror("ERR: open");
+    goto cleanup;
+  }
+  if (write(fd, "hello world\n", 12) >= 0) {
+    perror("ERR: write");
+    goto cleanup;
+  }
+  if (read(fd, buf, sizeof(buf)) != 0) {
+    perror("ERR: read");
+    goto cleanup;
+  }
+  puts("OK");
+ cleanup:
+  close(fd);
+  unlink(path);
+}
+
+void main_open_wronly() {
+  const char *path = "zig-cc.wronly.test";
+  int fd;
+  char buf[32];
+
+  fd = open(path, O_CREAT|O_TRUNC|O_WRONLY, 0644);
+  if (fd < 0) {
+    perror("ERR: open");
+    goto cleanup;
+  }
+  if (write(fd, "hello world\n", 12) != 12) {
+    perror("ERR: write");
+    goto cleanup;
+  }
+  if (read(fd, buf, sizeof(buf)) >= 0) {
+    perror("ERR: read");
+    goto cleanup;
+  }
+  puts("OK");
+ cleanup:
+  close(fd);
+  unlink(path);
+}
+
 int main(int argc, char** argv) {
   if (strcmp(argv[1],"ls")==0) {
     bool repeat = false;
@@ -95,6 +144,11 @@ int main(int argc, char** argv) {
         timeout = atoi(argv[2]);
     }
     main_sleepmillis(timeout);
+  } else if (strcmp(argv[1],"open-rdonly")==0) {
+    main_open_rdonly();
+
+  } else if (strcmp(argv[1],"open-wronly")==0) {
+    main_open_wronly();
 
   } else {
     fprintf(stderr, "unknown command: %s\n", argv[1]);

imports/wasi_snapshot_preview1/wasi_stdlib_test.go

@@ -311,3 +311,35 @@ func Test_Sleep(t *testing.T) {
 	require.True(t, time.Since(start) >= 100*time.Millisecond)
 	require.Equal(t, "OK\n", console)
 }
+
+func Test_open(t *testing.T) {
+	for toolchain, bin := range map[string][]byte{
+		"zig-cc": wasmZigCc,
+	} {
+		toolchain := toolchain
+		bin := bin
+		t.Run(toolchain, func(t *testing.T) {
+			testOpenReadOnly(t, bin)
+			testOpenWriteOnly(t, bin)
+		})
+	}
+}
+
+func testOpenReadOnly(t *testing.T, bin []byte) {
+	testOpen(t, "rdonly", bin)
+}
+
+func testOpenWriteOnly(t *testing.T, bin []byte) {
+	testOpen(t, "wronly", bin)
+}
+
+func testOpen(t *testing.T, cmd string, bin []byte) {
+	t.Run(cmd, func(t *testing.T) {
+		moduleConfig := wazero.NewModuleConfig().
+			WithArgs("wasi", "open-"+cmd).
+			WithFSConfig(wazero.NewFSConfig().WithDirMount(t.TempDir(), "/"))
+
+		console := compileAndRun(t, moduleConfig, bin)
+		require.Equal(t, "OK", strings.TrimSpace(console))
+	})
+}