Wasip3: File handing implementation

expected/wasm32-wasip3/defined-symbols.txt

@@ -336,6 +336,7 @@ __wasilibc_open_nomode
 __wasilibc_populate_preopens
 __wasilibc_pthread_self
 __wasilibc_random
+__wasilibc_read3
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
 __wasilibc_reset_preopens
@@ -344,6 +345,7 @@ __wasilibc_stat
 __wasilibc_tell
 __wasilibc_unlinkat
 __wasilibc_utimens
+__wasilibc_write3
 __wasm_call_dtors
 __wcscoll_l
 __wcsftime_l
@@ -1472,6 +1474,7 @@ wasip3_list_u8_free
 wasip3_option_string_free
 wasip3_string_dup
 wasip3_string_free
+wasip3_string_from_c
 wasip3_string_set
 wasip3_subtask_block_on
 wasip3_subtask_cancel

libc-bottom-half/CMakeLists.txt

@@ -164,6 +164,7 @@ if (WASI STREQUAL "p3")
   list(APPEND bottom_half_sources
     sources/wasip3.c
     sources/wasip3_file.c
+    sources/wasip3_file_utils.c
     sources/wasip3_stdio.c
     sources/wasip3_subtask.c
     sources/wasip3_tcp.c

libc-bottom-half/cloudlibc/src/common/errors.h

@@ -1,6 +1,6 @@
 #include <wasi/api.h>
 
-#ifdef __wasip2__
+#if defined(__wasip2__) || defined(__wasip3__)
 #include <errno.h>
 #include <stdlib.h>
 
@@ -9,9 +9,11 @@ static void translate_error(filesystem_error_code_t error) {
     case FILESYSTEM_ERROR_CODE_ACCESS:
         errno = EACCES;
         break;
+#ifdef __wasip2__
     case FILESYSTEM_ERROR_CODE_WOULD_BLOCK:
         errno = EAGAIN;
         break;
+#endif
     case FILESYSTEM_ERROR_CODE_ALREADY:
         errno = EALREADY;
         break;

libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c

@@ -16,6 +16,10 @@
 #include <common/errors.h>
 #endif
 
+#ifdef __wasip3__
+#include <wasi/wasip3_block.h>
+#endif
+
 #ifdef __wasip1__
 static_assert(O_APPEND == __WASI_FDFLAGS_APPEND, "Value mismatch");
 static_assert(O_DSYNC == __WASI_FDFLAGS_DSYNC, "Value mismatch");
@@ -87,7 +91,7 @@ int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) {
     return -1;
   }
   return newfd;
-#elif defined(__wasip2__)
+#elif defined(__wasip2__) || defined(__wasip3__)
   // Set up path flags
   filesystem_path_flags_t lookup_flags = 0;
   if ((oflag & O_NOFOLLOW) == 0)
@@ -140,6 +144,7 @@ int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) {
     return -1;
 
   // Construct a WASI string for the path
+#ifdef __wasip2__
   wasip2_string_t path2;
   if (wasip2_string_from_c(path, &path2) < 0)
     return -1;
@@ -162,9 +167,28 @@ int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) {
   // Update the descriptor table with the new handle
   return __wasilibc_add_file(new_handle, oflag);
 #elif defined(__wasip3__)
-  // TODO(wasip3)
-  errno = ENOTSUP;
-  return -1;
+  wasip3_string_t path3;
+  if (wasip3_string_from_c(path, &path3) < 0)
+    return -1;
+
+  // Open the file, yielding a new handle
+  filesystem_method_descriptor_open_at_args_t args;
+  args.self = file_handle;
+  args.flags = lookup_flags;
+  args.path = path3;
+  args.open_flags = open_flags;
+  args.path_flags = fs_flags;
+  filesystem_result_own_descriptor_error_code_t result;
+  wasip3_subtask_status_t status = filesystem_method_descriptor_open_at(&args, &result);
+  wasip3_subtask_block_on(status);
+  if (result.is_err) {
+    translate_error(result.val.err);
+    return -1;
+  }
+
+  // Update the descriptor table with the new handle
+  return __wasilibc_add_file(result.val.ok, oflag);
+#endif
 #else
 # error "Unsupported WASI version"
 #endif

libc-bottom-half/cloudlibc/src/libc/unistd/lseek.c

@@ -29,7 +29,7 @@ off_t __lseek(int fildes, off_t offset, int whence) {
     return -1;
   }
   return new_offset;
-#elif defined(__wasip2__)
+#elif defined(__wasip2__) || defined(__wasip3__)
   // Look up a stream for fildes
   descriptor_table_entry_t *entry = descriptor_table_get_ref(fildes);
   if (!entry)
@@ -39,10 +39,6 @@ off_t __lseek(int fildes, off_t offset, int whence) {
     return -1;
   }
   return entry->vtable->seek(entry->data, offset, whence);
-#elif defined(__wasip3__)
-  // TODO(wasip3)
-  errno = ENOTSUP;
-  return -1;
 #else
 # error "Unknown WASI version"
 #endif

libc-bottom-half/cloudlibc/src/libc/unistd/read.c

@@ -53,9 +53,7 @@ ssize_t read(int fildes, void *buf, size_t nbyte) {
     *off += contents.len;
   return contents.len;
 #elif defined(__wasip3__)
-  // TODO(wasip3)
-  errno = ENOTSUP;
-  return -1;
+  return __wasilibc_read3(fildes, buf, nbyte);
 #else
 # error "Unsupported WASI version"
 #endif

libc-bottom-half/cloudlibc/src/libc/unistd/write.c

@@ -72,9 +72,7 @@ ssize_t write(int fildes, const void *buf, size_t nbyte) {
     *off += contents.len;
   return contents.len;
 #elif defined(__wasip3__)
-  // TODO(wasip3)
-  errno = ENOTSUP;
-  return -1;
+  return __wasilibc_write3(fildes, buf, nbyte);
 #else
 # error "Unknown WASI version"
 #endif

libc-bottom-half/headers/private/wasi/descriptor_table.h

@@ -8,6 +8,11 @@
 #include <sys/stat.h>
 #include <netinet/in.h>
 
+#ifdef __wasip3__
+// create an alias to distinguish the handle type in the API
+typedef uint32_t waitable_t;
+#endif
+
 /**
  * Operations that are required of all descriptors registered as file
  * descriptors.
@@ -37,6 +42,12 @@ typedef struct descriptor_vtable_t {
   /// Same as `get_read_stream`, but for output streams.
   int (*get_write_stream)(void*, streams_borrow_output_stream_t*, off_t**, poll_own_pollable_t**);
 #endif
+#ifdef __wasip3__
+  /// Start an asynchronous read or write, returns zero on success.
+  /// Stores the waitable, status and offset location.
+  int (*read3)(void*, void *buf, size_t nbyte, waitable_t *waitable, wasip3_waitable_status_t *out, off_t**);
+  int (*write3)(void*, void const *buf, size_t nbyte, waitable_t *waitable, wasip3_waitable_status_t *out, off_t**);
+#endif
 
   /// Sets the nonblocking flag for this object to the specified value.
   int (*set_blocking)(void*, bool);

libc-bottom-half/headers/private/wasi/file_utils.h

@@ -3,14 +3,16 @@
 
 #include <wasi/version.h>
 
-#ifdef __wasip2__
+#if defined(__wasip2__) || defined(__wasip3__)
 #include <assert.h>
 #include <wasi/wasip2.h>
 #include <wasi/descriptor_table.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <errno.h>
+#endif
 
+#ifdef __wasip2__
 /// Handles a `wasi:io/streams.stream-error` for a `read`-style operation.
 ///
 /// If the error indicates "closed" then 0 is returned to mean EOF. Otherwise
@@ -46,7 +48,9 @@ static int wasip2_handle_write_error(streams_stream_error_t error) {
 // Returns 0 if `s` is valid utf-8.
 // Returns -1 and sets errno to `ENOENT` if `s` is not valid utf-8.
 int wasip2_string_from_c(const char *s, wasip2_string_t* out);
+#endif
 
+#if defined(__wasip2__) || defined(__wasip3__)
 // Succeed only if fd is bound to a file handle in the descriptor table
 static int fd_to_file_handle(int fd, filesystem_borrow_descriptor_t* result) {
   descriptor_table_entry_t* entry = descriptor_table_get_ref(fd);
@@ -58,7 +62,9 @@ static int fd_to_file_handle(int fd, filesystem_borrow_descriptor_t* result) {
   }
   return entry->vtable->get_file(entry->data, result);
 }
+#endif
 
+#ifdef __wasip2__
 // Gets an `output-stream` borrow from the `fd` provided.
 int __wasilibc_write_stream(int fd,
                             streams_borrow_output_stream_t *out,
@@ -96,4 +102,13 @@ static unsigned dir_entry_type_to_d_type(filesystem_descriptor_type_t ty) {
 
 #endif
 
+#ifdef __wasip3__
+#include <wasi/descriptor_table.h>
+
+int wasip3_string_from_c(const char *s, wasip3_string_t* out);
+
+ssize_t __wasilibc_write3(int fildes, void const *buf, size_t nbyte);
+ssize_t __wasilibc_read3(int fildes, void *buf, size_t nbyte);
+#endif
+
 #endif