Abstract POSIX filesystem functions (#2585)

To allow non-POSIX platforms such as Windows to support WASI libc
filesystem functionality, create a set of wrapper functions which provide a
platform-agnostic interface to interact with the host filesystem. For now,
the Windows implementation is stubbed but this will be implemented
properly in a future PR. There are no functional changes in this change,
just a reorganization of code to move any direct POSIX references out of
posix.c in the libc implementation into posix_file.c under the shared
POSIX sources.

See https://github.com/bytecodealliance/wasm-micro-runtime/issues/2495 for a
more detailed overview of the plan to port the WASI libc filesystem to Windows.

core/shared/platform/windows/platform_internal.h

@@ -137,6 +137,14 @@ bh_atomic_thread_fence(int mem_order);
 
 #define os_atomic_thread_fence bh_atomic_thread_fence
 
+typedef HANDLE os_file_handle;
+typedef void *os_dir_stream;
+#if WASM_ENABLE_UVWASI != 1
+typedef HANDLE os_raw_file_handle;
+#else
+typedef uint32_t os_raw_file_handle;
+#endif
+
 #ifdef __cplusplus
 }
 #endif

core/shared/platform/windows/shared_platform.cmake

@@ -13,6 +13,13 @@ include_directories(${PLATFORM_SHARED_DIR}/../include)
 file (GLOB_RECURSE source_all ${PLATFORM_SHARED_DIR}/*.c
 			      ${PLATFORM_SHARED_DIR}/*.cpp)
 
+if (NOT WAMR_BUILD_LIBC_WASI EQUAL 1)
+    list(REMOVE_ITEM source_all ${PLATFORM_SHARED_DIR}/win_file.c)
+else()
+    include (${CMAKE_CURRENT_LIST_DIR}/../common/libc-util/platform_common_libc_util.cmake)
+    set(source_all ${source_all} ${PLATFORM_COMMON_LIBC_UTIL_SOURCE})
+endif()
+
 set (PLATFORM_SHARED_SOURCE ${source_all})
 
 file (GLOB header ${PLATFORM_SHARED_DIR}/../include/*.h)

core/shared/platform/windows/win_file.c

@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2023 Intel Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include "platform_api_extension.h"
+#include "platform_internal.h"
+
+__wasi_errno_t
+os_fstat(os_file_handle handle, struct __wasi_filestat_t *buf)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_fstatat(os_file_handle handle, const char *path,
+           struct __wasi_filestat_t *buf, __wasi_lookupflags_t lookup_flags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_file_get_fdflags(os_file_handle handle, __wasi_fdflags_t *flags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_file_set_fdflags(os_file_handle handle, __wasi_fdflags_t flags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_file_get_access_mode(os_file_handle handle,
+                        wasi_libc_file_access_mode *access_mode)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_fdatasync(os_file_handle handle)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_fsync(os_file_handle handle)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_open_preopendir(const char *path, os_file_handle *out)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_openat(os_file_handle handle, const char *path, __wasi_oflags_t oflags,
+          __wasi_fdflags_t fs_flags, __wasi_lookupflags_t lookup_flags,
+          wasi_libc_file_access_mode read_write_mode, os_file_handle *out)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_close(os_file_handle handle, bool is_stdio)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_preadv(os_file_handle handle, const struct __wasi_iovec_t *iov, int iovcnt,
+          __wasi_filesize_t offset, size_t *nread)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_pwritev(os_file_handle handle, const struct __wasi_ciovec_t *iov, int iovcnt,
+           __wasi_filesize_t offset, size_t *nwritten)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_readv(os_file_handle handle, const struct __wasi_iovec_t *iov, int iovcnt,
+         size_t *nread)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_writev(os_file_handle handle, const struct __wasi_ciovec_t *iov, int iovcnt,
+          size_t *nwritten)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_fallocate(os_file_handle handle, __wasi_filesize_t offset,
+             __wasi_filesize_t length)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_ftruncate(os_file_handle handle, __wasi_filesize_t size)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_futimens(os_file_handle handle, __wasi_timestamp_t access_time,
+            __wasi_timestamp_t modification_time, __wasi_fstflags_t fstflags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_utimensat(os_file_handle handle, const char *path,
+             __wasi_timestamp_t access_time,
+             __wasi_timestamp_t modification_time, __wasi_fstflags_t fstflags,
+             __wasi_lookupflags_t lookup_flags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_readlinkat(os_file_handle handle, const char *path, char *buf,
+              size_t bufsize, size_t *nread)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_linkat(os_file_handle from_handle, const char *from_path,
+          os_file_handle to_handle, const char *to_path,
+          __wasi_lookupflags_t lookup_flags)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_symlinkat(const char *old_path, os_file_handle handle, const char *new_path)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_mkdirat(os_file_handle handle, const char *path)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_renameat(os_file_handle old_handle, const char *old_path,
+            os_file_handle new_handle, const char *new_path)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_unlinkat(os_file_handle handle, const char *path, bool is_dir)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_lseek(os_file_handle handle, __wasi_filedelta_t offset,
+         __wasi_whence_t whence, __wasi_filesize_t *new_offset)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_fadvise(os_file_handle handle, __wasi_filesize_t offset,
+           __wasi_filesize_t length, __wasi_advice_t advice)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_isatty(os_file_handle handle)
+{
+    return __WASI_ENOSYS;
+}
+
+os_file_handle
+os_convert_stdin_handle(os_raw_file_handle raw_stdin)
+{
+    return INVALID_HANDLE_VALUE;
+}
+
+os_file_handle
+os_convert_stdout_handle(os_raw_file_handle raw_stdout)
+{
+    return INVALID_HANDLE_VALUE;
+}
+
+os_file_handle
+os_convert_stderr_handle(os_raw_file_handle raw_stderr)
+{
+    return INVALID_HANDLE_VALUE;
+}
+
+__wasi_errno_t
+os_fdopendir(os_file_handle handle, os_dir_stream *dir_stream)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_rewinddir(os_dir_stream dir_stream)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_seekdir(os_dir_stream dir_stream, __wasi_dircookie_t position)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_readdir(os_dir_stream dir_stream, __wasi_dirent_t *entry,
+           const char **d_name)
+{
+    return __WASI_ENOSYS;
+}
+
+__wasi_errno_t
+os_closedir(os_dir_stream dir_stream)
+{
+    return __WASI_ENOSYS;
+}
+
+os_dir_stream
+os_get_invalid_dir_stream()
+{
+    return NULL;
+}
+
+bool
+os_is_dir_stream_valid(os_dir_stream *dir_stream)
+{
+    return false;
+}
+
+os_file_handle
+os_get_invalid_handle()
+{
+    return INVALID_HANDLE_VALUE;
+}
+
+bool
+os_is_handle_valid(os_file_handle *handle)
+{
+    return false;
+}
+
+char *
+os_realpath(const char *path, char *resolved_path)
+{
+    return NULL;
+}