path_unlink_file()

Unlink a file, deleting it if the number of hardlinks is 1.

Description

The path_unlink_file() function unlinks a file at the specified path. If the file has only one hardlink (i.e., its link count is 1), it will be deleted from the file system. It requires the PATH_UNLINK_FILE right on the base file descriptor.

On POSIX systems, a similar functionality is provided by the unlink() function. It removes the specified file from the file system. If the file has no other hardlinks, it is completely deleted. The unlink() function is part of the POSIX standard and is widely supported across different platforms.

Syntax

  ;;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
  ;;; Return `errno::isdir` if the path refers to a directory.
  ;;; Unlink a file.
  (@interface func (export "path_unlink_file")
    (param $fd $fd)
    ;;; The path to a file to unlink.
    (param $path string)
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: A mutable reference to the function environment.
• fd: The file descriptor representing the base directory from which the path is understood.
• path: A wasm pointer to a null-terminated string containing the path of the file to be unlinked.
• path_len: The length of the path string.

Return Value

The function returns an Errno value indicating the success or failure of the operation. If the operation is successful, it returns Errno::Success. Otherwise, it returns an appropriate Errno value.

Logging

This function has been instrumented with debug-level logging. It will log the following information:

• %fd: The file descriptor representing the base directory.
• path: The path string.

Note

The path_unlink_file() function unlinks a file at the specified path, deleting it if the number of hardlinks is 1. It checks the necessary rights on the base file descriptor. On POSIX systems, a similar functionality is provided by the unlink() function.