path_link()

Create a hard link.

Description

The path_link() function creates a hard link between two files. It creates a new directory entry with the specified name in the destination directory, which refers to the same underlying file as the source file.

On POSIX systems, a similar functionality is provided by the link() function. It creates a new link (directory entry) for an existing file. The new link and the original file refer to the same inode and share the same content.

Syntax

  ;;; Note: This is similar to `linkat` in POSIX.
  ;;; Create a hard link.
  (@interface func (export "path_link")
    (param $old_fd $fd)
    ;;; Flags determining the method of how the path is resolved.
    (param $old_flags $lookupflags)
    ;;; The source path from which to link.
    (param $old_path string)
    ;;; The working directory at which the resolution of the new path starts.
    (param $new_fd $fd)
    ;;; The destination path at which to create the hard link.
    (param $new_path string)
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: A mutable reference to the function environment.
• old_fd: The file descriptor representing the directory that the old_path is relative to.
• old_flags: Flags to control how the old_path is understood.
• old_path: A wasm pointer to a null-terminated string containing the old file path.
• old_path_len: The length of the old_path string.
• new_fd: The file descriptor representing the directory that the new_path is relative to.
• new_path: A wasm pointer to a null-terminated string containing the new file path.
• new_path_len: The length of the new_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:

• %old_fd: The file descriptor representing the source directory.
• %new_fd: The file descriptor representing the destination directory.
• old_path: The old file path.
• new_path: The new file path.

Note

The path_link() function creates a hard link between two files. It checks if the necessary rights are present on both the source and target directories. It then creates a new directory entry in the target directory with the specified name, linking it to the source file.

On POSIX systems, a similar functionality is provided by the link() function.