Vendor WASI WITs in this repository

CMakeLists.txt

@@ -143,6 +143,9 @@ else()
   message(FATAL_ERROR "Unknown WASI version: ${WASI}")
 endif()
 
+set(wasip2-version 0.2.0)
+set(wasip3-version 0.3.0-rc-2026-01-06)
+
 include(bindings)
 include(builtins)
 if (NOT (WASI STREQUAL "p1"))
@@ -151,6 +154,7 @@ endif()
 include(check-symbols)
 include(clang-format)
 include(wasm-tools)
+include(wasi-wits)
 
 # =============================================================================
 # Generic top-level build flags/settings

cmake/bindings.cmake

@@ -4,8 +4,6 @@ if (NOT BINDINGS_TARGET)
   return()
 endif()
 
-include(ExternalProject)
-
 # If `wit-bindgen` is on the system and has the right version, favor that,
 # otherwise download a known good version.
 find_program(WIT_BINDGEN_EXECUTABLE NAMES wit-bindgen)
@@ -37,54 +35,9 @@ else()
   set(wit_bindgen ${WIT_BINDGEN_EXECUTABLE})
 endif()
 
-# If `wkg` is on the system and has the right version, favor that,
-# otherwise download a known good version.
-find_program(WKG_EXECUTABLE NAMES wkg)
-if(WKG_EXECUTABLE)
-  message(STATUS "Found wkg: ${WKG_EXECUTABLE}")
-
-  execute_process(
-    COMMAND ${WKG_EXECUTABLE} --version
-    OUTPUT_VARIABLE WKG_VERSION
-    OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-  if (NOT (WKG_VERSION MATCHES "0\\.13\\.0"))
-    message(WARNING "wkg version 0.13.0 is required, found: ${WKG_VERSION}")
-    set(WKG_EXECUTABLE "")
-  endif()
-endif()
-
-if (NOT WKG_EXECUTABLE)
-  include(ba-download)
-  ba_download(
-    wkg
-    "https://github.com/bytecodealliance/wasm-pkg-tools"
-    "0.13.0"
-  )
-  ExternalProject_Get_Property(wkg DOWNLOADED_FILE)
-  set(wkg_bin ${DOWNLOADED_FILE})
-else()
-  add_custom_target(wkg)
-  set(wkg_bin ${WKG_EXECUTABLE})
-endif()
-
 set(bottom_half "${CMAKE_SOURCE_DIR}/libc-bottom-half")
 
-set(wasip2_wit_dir ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2/wit)
-set(wasip2-version 0.2.0)
 file(MAKE_DIRECTORY ${wasip2_wit_dir})
-configure_file(${CMAKE_SOURCE_DIR}/wasi/wasi-libc-wasip2.wit.in ${wasip2_wit_dir}/wasi-libc-wasip2.wit)
-set(wasip2_stamp ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2/.wit-fetch-stamp)
-add_custom_command(
-  OUTPUT ${wasip2_stamp}
-  COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2
-  COMMAND ${wkg_bin} wit fetch
-  COMMAND ${CMAKE_COMMAND} -E touch ${wasip2_stamp}
-  WORKING_DIRECTORY ${wasip2_wit_dir}/..
-  DEPENDS wkg ${wasip2_wit_dir}/wasi-libc-wasip2.wit
-  COMMENT "Fetching WASI P2 dependencies"
-)
-add_custom_target(wasip2-wits DEPENDS ${wasip2_stamp})
 add_custom_target(
   bindings-p2
   COMMAND
@@ -120,28 +73,13 @@ add_custom_target(
       --rename wasi:cli/terminal-stdin@${wasip2-version}=terminal_stdin
       --rename wasi:cli/terminal-stdout@${wasip2-version}=terminal_stdout
       --rename wasi:cli/terminal-stderr@${wasip2-version}=terminal_stderr
-      ${wasip2_wit_dir}
+      ${CMAKE_SOURCE_DIR}/wasi/p2/wit
   COMMAND cmake -E copy wasip2.h ${bottom_half}/headers/public/wasi/__generated_wasip2.h
   COMMAND cmake -E copy wasip2_component_type.o ${bottom_half}/sources
   COMMAND cmake -E copy wasip2.c ${bottom_half}/sources
   DEPENDS wit-bindgen wkg wasip2-wits
 )
 
-set(wasip3_wit_dir ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3/wit)
-set(wasip3-version 0.3.0-rc-2026-01-06)
-file(MAKE_DIRECTORY ${wasip3_wit_dir})
-configure_file(${CMAKE_SOURCE_DIR}/wasi/wasi-libc-wasip3.wit.in ${wasip3_wit_dir}/wasi-libc-wasip3.wit)
-set(wasip3_stamp ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3/.wit-fetch-stamp)
-add_custom_command(
-  OUTPUT ${wasip3_stamp}
-  COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3
-  COMMAND ${wkg_bin} wit fetch
-  COMMAND ${CMAKE_COMMAND} -E touch ${wasip3_stamp}
-  WORKING_DIRECTORY ${wasip3_wit_dir}/..
-  DEPENDS wkg ${wasip3_wit_dir}/wasi-libc-wasip3.wit
-  COMMENT "Fetching WASI P3 dependencies"
-)
-add_custom_target(wasip3-wits DEPENDS ${wasip3_stamp})
 add_custom_target(
   bindings-p3
   COMMAND
@@ -169,7 +107,7 @@ add_custom_target(
       --rename wasi:cli/terminal-stdin@${wasip3-version}=terminal_stdin
       --rename wasi:cli/terminal-stdout@${wasip3-version}=terminal_stdout
       --rename wasi:cli/terminal-stderr@${wasip3-version}=terminal_stderr
-      ${wasip3_wit_dir}
+      ${CMAKE_SOURCE_DIR}/wasi/p3/wit
   COMMAND cmake -E copy wasip3.h ${bottom_half}/headers/public/wasi/__generated_wasip3.h
   COMMAND cmake -E copy wasip3_component_type.o ${bottom_half}/sources
   COMMAND cmake -E copy wasip3.c ${bottom_half}/sources

cmake/wasi-wits.cmake

@@ -0,0 +1,49 @@
+# Helper rules to download and vendor WITs used for WASI in this repository for
+# bindings generation and future use.
+
+# If `wkg` is on the system and has the right version, favor that,
+# otherwise download a known good version.
+find_program(WKG_EXECUTABLE NAMES wkg)
+if(WKG_EXECUTABLE)
+  message(STATUS "Found wkg: ${WKG_EXECUTABLE}")
+
+  execute_process(
+    COMMAND ${WKG_EXECUTABLE} --version
+    OUTPUT_VARIABLE WKG_VERSION
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+  if (NOT (WKG_VERSION MATCHES "0\\.13\\.0"))
+    message(WARNING "wkg version 0.13.0 is required, found: ${WKG_VERSION}")
+    set(WKG_EXECUTABLE "")
+  endif()
+endif()
+
+if (NOT WKG_EXECUTABLE)
+  include(ba-download)
+  ba_download(
+    wkg
+    "https://github.com/bytecodealliance/wasm-pkg-tools"
+    "0.13.0"
+  )
+  ExternalProject_Get_Property(wkg DOWNLOADED_FILE)
+  set(wkg_bin ${DOWNLOADED_FILE})
+else()
+  add_custom_target(wkg)
+  set(wkg_bin ${WKG_EXECUTABLE})
+endif()
+
+foreach(version p2 p3)
+  set(wit_dir ${CMAKE_SOURCE_DIR}/wasi/${version}/wit)
+  set(stamp ${CMAKE_BINARY_DIR}/wasi${version}-wit.stamp)
+
+  configure_file(${wit_dir}/wasi-libc.wit.in ${wit_dir}/wasi-libc.wit)
+  add_custom_command(
+    OUTPUT ${stamp}
+    COMMAND ${wkg_bin} wit fetch
+    COMMAND ${CMAKE_COMMAND} -E touch ${stamp}
+    WORKING_DIRECTORY ${wit_dir}/..
+    DEPENDS wkg ${wit_dir}/wasi-libc.wit
+    COMMENT "Fetching WASI${version} dependencies"
+  )
+  add_custom_target(wasi${version}-wits DEPENDS ${stamp})
+endforeach()

libc-bottom-half/CMakeLists.txt

@@ -215,8 +215,16 @@ if (WASI STREQUAL "p1")
     COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_OBJECTS:crt1-command> ${crt_sysroot}/crt1-command.o
     DEPENDS crt1-command $<TARGET_OBJECTS:crt1-command>
   )
-elseif (WASI STREQUAL "p2")
-  # wasip2: crt1-command.o is modified from what CMake produces to
+else()
+  if (WASI STREQUAL "p2")
+    set(world wasi:cli/command@${wasip2-version})
+  elseif (WASI STREQUAL "p3")
+    set(world wasi:cli/command@${wasip3-version})
+  else()
+    message(FATAL_ERROR "Unknown WASI version: ${WASI}")
+  endif()
+
+  # wasip2+: crt1-command.o is modified from what CMake produces to
   # additionally have a custom section representing the type information needed
   # for its contained export. This is the `wasi:cli/run` interface, for example.
   #
@@ -238,25 +246,12 @@ elseif (WASI STREQUAL "p2")
     OUTPUT ${crt_sysroot}/crt1-command.o
     COMMAND
       ${wasm_tools} component embed
-        ${wasip2_wit_dir}
+        ${CMAKE_SOURCE_DIR}/wasi/${WASI}/wit
         $<TARGET_OBJECTS:crt1-command>
-        --world wasi:cli/command@0.2.0
+        --world ${world}
         -o ${crt_sysroot}/crt1-command.o
-    DEPENDS crt1-command wasip2-wits $<TARGET_OBJECTS:crt1-command> wasm-tools
+    DEPENDS crt1-command $<TARGET_OBJECTS:crt1-command> wasm-tools
   )
-elseif (WASI STREQUAL "p3")
-  add_custom_command(
-    OUTPUT ${crt_sysroot}/crt1-command.o
-    COMMAND
-      ${wasm_tools} component embed
-        ${wasip3_wit_dir}
-        $<TARGET_OBJECTS:crt1-command>
-        --world wasi:cli/command@0.3.0-rc-2026-01-06
-        -o ${crt_sysroot}/crt1-command.o
-    DEPENDS crt1-command wasip3-wits $<TARGET_OBJECTS:crt1-command> wasm-tools
-  )
-else()
-  message(FATAL_ERROR "Unknown WASI version: ${WASI}")
 endif()
 
 # Provide a plain crt1.o for toolchain compatibility, identical to

wasi/p2/wit/deps/wasi-cli-0.2.0/package.wit

@@ -0,0 +1,159 @@
+package wasi:cli@0.2.0;
+
+interface environment {
+  /// Get the POSIX-style environment variables.
+  ///
+  /// Each environment variable is provided as a pair of string variable names
+  /// and string value.
+  ///
+  /// Morally, these are a value import, but until value imports are available
+  /// in the component model, this import function should return the same
+  /// values each time it is called.
+  get-environment: func() -> list<tuple<string, string>>;
+
+  /// Get the POSIX-style arguments to the program.
+  get-arguments: func() -> list<string>;
+
+  /// Return a path that programs should use as their initial current working
+  /// directory, interpreting `.` as shorthand for this.
+  initial-cwd: func() -> option<string>;
+}
+
+interface exit {
+  /// Exit the current instance and any linked instances.
+  exit: func(status: result);
+}
+
+interface run {
+  /// Run the program.
+  run: func() -> result;
+}
+
+interface stdin {
+  use wasi:io/streams@0.2.0.{input-stream};
+
+  get-stdin: func() -> input-stream;
+}
+
+interface stdout {
+  use wasi:io/streams@0.2.0.{output-stream};
+
+  get-stdout: func() -> output-stream;
+}
+
+interface stderr {
+  use wasi:io/streams@0.2.0.{output-stream};
+
+  get-stderr: func() -> output-stream;
+}
+
+/// Terminal input.
+///
+/// In the future, this may include functions for disabling echoing,
+/// disabling input buffering so that keyboard events are sent through
+/// immediately, querying supported features, and so on.
+interface terminal-input {
+  /// The input side of a terminal.
+  resource terminal-input;
+}
+
+/// Terminal output.
+///
+/// In the future, this may include functions for querying the terminal
+/// size, being notified of terminal size changes, querying supported
+/// features, and so on.
+interface terminal-output {
+  /// The output side of a terminal.
+  resource terminal-output;
+}
+
+/// An interface providing an optional `terminal-input` for stdin as a
+/// link-time authority.
+interface terminal-stdin {
+  use terminal-input.{terminal-input};
+
+  /// If stdin is connected to a terminal, return a `terminal-input` handle
+  /// allowing further interaction with it.
+  get-terminal-stdin: func() -> option<terminal-input>;
+}
+
+/// An interface providing an optional `terminal-output` for stdout as a
+/// link-time authority.
+interface terminal-stdout {
+  use terminal-output.{terminal-output};
+
+  /// If stdout is connected to a terminal, return a `terminal-output` handle
+  /// allowing further interaction with it.
+  get-terminal-stdout: func() -> option<terminal-output>;
+}
+
+/// An interface providing an optional `terminal-output` for stderr as a
+/// link-time authority.
+interface terminal-stderr {
+  use terminal-output.{terminal-output};
+
+  /// If stderr is connected to a terminal, return a `terminal-output` handle
+  /// allowing further interaction with it.
+  get-terminal-stderr: func() -> option<terminal-output>;
+}
+
+world imports {
+  import environment;
+  import exit;
+  import wasi:io/error@0.2.0;
+  import wasi:io/poll@0.2.0;
+  import wasi:io/streams@0.2.0;
+  import stdin;
+  import stdout;
+  import stderr;
+  import terminal-input;
+  import terminal-output;
+  import terminal-stdin;
+  import terminal-stdout;
+  import terminal-stderr;
+  import wasi:clocks/monotonic-clock@0.2.0;
+  import wasi:clocks/wall-clock@0.2.0;
+  import wasi:filesystem/types@0.2.0;
+  import wasi:filesystem/preopens@0.2.0;
+  import wasi:sockets/network@0.2.0;
+  import wasi:sockets/instance-network@0.2.0;
+  import wasi:sockets/udp@0.2.0;
+  import wasi:sockets/udp-create-socket@0.2.0;
+  import wasi:sockets/tcp@0.2.0;
+  import wasi:sockets/tcp-create-socket@0.2.0;
+  import wasi:sockets/ip-name-lookup@0.2.0;
+  import wasi:random/random@0.2.0;
+  import wasi:random/insecure@0.2.0;
+  import wasi:random/insecure-seed@0.2.0;
+}
+world command {
+  import environment;
+  import exit;
+  import wasi:io/error@0.2.0;
+  import wasi:io/poll@0.2.0;
+  import wasi:io/streams@0.2.0;
+  import stdin;
+  import stdout;
+  import stderr;
+  import terminal-input;
+  import terminal-output;
+  import terminal-stdin;
+  import terminal-stdout;
+  import terminal-stderr;
+  import wasi:clocks/monotonic-clock@0.2.0;
+  import wasi:clocks/wall-clock@0.2.0;
+  import wasi:filesystem/types@0.2.0;
+  import wasi:filesystem/preopens@0.2.0;
+  import wasi:sockets/network@0.2.0;
+  import wasi:sockets/instance-network@0.2.0;
+  import wasi:sockets/udp@0.2.0;
+  import wasi:sockets/udp-create-socket@0.2.0;
+  import wasi:sockets/tcp@0.2.0;
+  import wasi:sockets/tcp-create-socket@0.2.0;
+  import wasi:sockets/ip-name-lookup@0.2.0;
+  import wasi:random/random@0.2.0;
+  import wasi:random/insecure@0.2.0;
+  import wasi:random/insecure-seed@0.2.0;
+
+  export run;
+}