wasi: Add UVWASI interface

tools/wasi/CMakeLists.txt

@@ -8,7 +8,7 @@ add_library(wasi)
 add_library(fizzy::wasi ALIAS wasi)
 target_include_directories(wasi PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(wasi PUBLIC fizzy::fizzy-internal PRIVATE uvwasi::uvwasi)
-target_sources(wasi PRIVATE wasi.cpp wasi.hpp)
+target_sources(wasi PRIVATE wasi.cpp wasi.hpp uvwasi.hpp uvwasi.cpp)
 
 add_executable(fizzy-wasi)
 target_link_libraries(fizzy-wasi PRIVATE fizzy::wasi)

tools/wasi/uvwasi.cpp

@@ -0,0 +1,69 @@
+// Fizzy: A fast WebAssembly interpreter
+// Copyright 2021 The Fizzy Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "uvwasi.hpp"
+#include <uvwasi.h>
+
+namespace fizzy::wasi
+{
+namespace
+{
+class UVWASIImpl final : public UVWASI
+{
+    /// UVWASI state.
+    uvwasi_t m_state{};
+
+public:
+    uvwasi_errno_t init(uvwasi_size_t argc, const char** argv) noexcept final
+    {
+        // Initialisation settings.
+        // TODO: Make const after https://github.com/nodejs/uvwasi/pull/155 is merged.
+        uvwasi_options_t options = {
+            3,           // sizeof fd_table
+            0, nullptr,  // NOTE: no remappings
+            argc, argv,
+            nullptr,  // TODO: support env
+            0, 1, 2,
+            nullptr,  // NOTE: no special allocator
+        };
+        return uvwasi_init(&m_state, &options);
+    }
+
+    uvwasi_errno_t proc_exit(uvwasi_exitcode_t exit_code) noexcept final
+    {
+        return uvwasi_proc_exit(&m_state, exit_code);
+    }
+
+    uvwasi_errno_t fd_write(uvwasi_fd_t fd, const uvwasi_ciovec_t* iovs, uvwasi_size_t iovs_len,
+        uvwasi_size_t* nwritten) noexcept final
+    {
+        return uvwasi_fd_write(&m_state, fd, iovs, iovs_len, nwritten);
+    }
+
+    uvwasi_errno_t fd_read(uvwasi_fd_t fd, const uvwasi_iovec_t* iovs, uvwasi_size_t iovs_len,
+        uvwasi_size_t* nread) noexcept final
+    {
+        return uvwasi_fd_read(&m_state, fd, iovs, iovs_len, nread);
+    }
+
+    uvwasi_errno_t fd_prestat_get(uvwasi_fd_t fd, uvwasi_prestat_t* buf) noexcept final
+    {
+        return uvwasi_fd_prestat_get(&m_state, fd, buf);
+    }
+
+    uvwasi_errno_t environ_sizes_get(
+        uvwasi_size_t* environ_count, uvwasi_size_t* environ_buf_size) noexcept final
+    {
+        return uvwasi_environ_sizes_get(&m_state, environ_count, environ_buf_size);
+    }
+};
+}  // namespace
+
+UVWASI::~UVWASI() {}
+
+std::unique_ptr<UVWASI> create_uvwasi()
+{
+    return std::make_unique<UVWASIImpl>();
+}
+}  // namespace fizzy::wasi

tools/wasi/uvwasi.hpp

@@ -0,0 +1,36 @@
+// Fizzy: A fast WebAssembly interpreter
+// Copyright 2021 The Fizzy Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <wasi_types.h>
+#include <memory>
+
+namespace fizzy::wasi
+{
+/// UVWASI interface.
+class UVWASI
+{
+public:
+    virtual ~UVWASI();
+
+    virtual uvwasi_errno_t init(uvwasi_size_t argc, const char** argv) noexcept = 0;
+
+    virtual uvwasi_errno_t proc_exit(uvwasi_exitcode_t exit_code) noexcept = 0;
+
+    virtual uvwasi_errno_t fd_write(uvwasi_fd_t fd, const uvwasi_ciovec_t* iovs,
+        uvwasi_size_t iovs_len, uvwasi_size_t* nwritten) noexcept = 0;
+
+    virtual uvwasi_errno_t fd_read(uvwasi_fd_t fd, const uvwasi_iovec_t* iovs,
+        uvwasi_size_t iovs_len, uvwasi_size_t* nread) noexcept = 0;
+
+    virtual uvwasi_errno_t fd_prestat_get(uvwasi_fd_t fd, uvwasi_prestat_t* buf) noexcept = 0;
+
+    virtual uvwasi_errno_t environ_sizes_get(
+        uvwasi_size_t* environ_count, uvwasi_size_t* environ_buf_size) noexcept = 0;
+};
+
+std::unique_ptr<UVWASI> create_uvwasi();
+
+}  // namespace fizzy::wasi

tools/wasi/wasi.cpp

@@ -6,6 +6,7 @@
 #include "execute.hpp"
 #include "limits.hpp"
 #include "parser.hpp"
+#include "uvwasi.hpp"
 #include <uvwasi.h>
 #include <cassert>
 #include <filesystem>
@@ -14,21 +15,18 @@
 
 namespace fizzy::wasi
 {
+UVWASI* uvwasi;
+
 namespace
 {
-// Global state.
-// NOTE: we do not care about uvwasi_destroy(), because it only clears file descriptors (currently)
-// and we are a single-run tool. This may change in the future and should reevaluate.
-uvwasi_t state;
-
 ExecutionResult return_enosys(std::any&, Instance&, const Value*, ExecutionContext&) noexcept
 {
     return Value{uint32_t{UVWASI_ENOSYS}};
 }
 
 ExecutionResult proc_exit(std::any&, Instance&, const Value* args, ExecutionContext&) noexcept
 {
-    uvwasi_proc_exit(&state, static_cast<uvwasi_exitcode_t>(args[0].as<uint32_t>()));
+    uvwasi->proc_exit(static_cast<uvwasi_exitcode_t>(args[0].as<uint32_t>()));
     // Should not reach this.
     return Trap;
 }
@@ -49,7 +47,7 @@ ExecutionResult fd_write(
         return Value{uint32_t{ret}};
 
     uvwasi_size_t nwritten;
-    ret = uvwasi_fd_write(&state, static_cast<uvwasi_fd_t>(fd), iovs.data(), iov_cnt, &nwritten);
+    ret = uvwasi->fd_write(static_cast<uvwasi_fd_t>(fd), iovs.data(), iov_cnt, &nwritten);
     uvwasi_serdes_write_uint32_t(instance.memory->data(), nwritten_ptr, nwritten);
 
     return Value{uint32_t{ret}};
@@ -71,7 +69,7 @@ ExecutionResult fd_read(
         return Value{uint32_t{ret}};
 
     uvwasi_size_t nread;
-    ret = uvwasi_fd_read(&state, static_cast<uvwasi_fd_t>(fd), iovs.data(), iov_cnt, &nread);
+    ret = uvwasi->fd_read(static_cast<uvwasi_fd_t>(fd), iovs.data(), iov_cnt, &nread);
     uvwasi_serdes_write_uint32_t(instance.memory->data(), nread_ptr, nread);
 
     return Value{uint32_t{ret}};
@@ -84,7 +82,7 @@ ExecutionResult fd_prestat_get(
     const auto prestat_ptr = args[1].as<uint32_t>();
 
     uvwasi_prestat_t buf;
-    uvwasi_errno_t ret = uvwasi_fd_prestat_get(&state, fd, &buf);
+    uvwasi_errno_t ret = uvwasi->fd_prestat_get(fd, &buf);
 
     uvwasi_serdes_write_prestat_t(instance.memory->data(), prestat_ptr, &buf);
 
@@ -159,18 +157,10 @@ std::unique_ptr<Instance> instantiate(bytes_view wasm_binary)
 
 bool run(Instance& instance, int argc, const char* argv[], std::ostream& err)
 {
-    // Initialisation settings.
-    // TODO: Make const after https://github.com/nodejs/uvwasi/pull/155 is merged.
-    uvwasi_options_t options = {
-        3,           // sizeof fd_table
-        0, nullptr,  // NOTE: no remappings
-        static_cast<uvwasi_size_t>(argc), argv,
-        nullptr,  // TODO: support env
-        0, 1, 2,
-        nullptr,  // NOTE: no special allocator
-    };
+    if (!uvwasi)
+        uvwasi = create_uvwasi().release();
 
-    const uvwasi_errno_t uvwasi_err = uvwasi_init(&state, &options);
+    const uvwasi_errno_t uvwasi_err = uvwasi->init(static_cast<uvwasi_size_t>(argc), argv);
     if (uvwasi_err != UVWASI_ESUCCESS)
     {
         err << "Failed to initialise UVWASI: " << uvwasi_embedder_err_code_to_string(uvwasi_err)