chdir()

Sets the current working directory.

Description

The chdir() function changes the current working directory of the process to the specified directory. It allows processes to have a different working directory from the directory in which they were started.

In POSIX systems, the current working directory represents the directory in the file system from which the process is currently executing. By changing the current working directory, applications can navigate the file system and perform file operations relative to the new directory.

The chdir() function takes a path as input and sets it as the new current working directory. If the directory specified by the path does not exist, the function returns Errno::Noent to indicate that the directory could not be found.

Syntax

  ;;; Sets the current working directory
  (@interface func (export "chdir")
    ;;; Path to change the current working directory to
    (param $path string)
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: The function environment.
• path: A pointer to a null-terminated string that represents the path of the new working directory.
• path_len: The length of the path string.

Return Value

The function returns an Errno value indicating the result of the operation. If the operation is successful, it returns Errno::Success. If the specified directory does not exist, it returns Errno::Noent.

Logging

This function is instrumented with debug level logging. It includes the following field for debugging purposes:

• path: The path of the new working directory.

Note

• The chdir() function sets the current working directory of the process to the specified directory.
• It first retrieves the path string from the memory using the provided path pointer and path_len.
• The function then checks if the specified directory exists by attempting to read its contents using the WASI file system APIs. If the read operation fails, it returns Errno::Noent.
• If the directory exists, it updates the current working directory in the WASI state to the specified path.
• Finally, it returns Errno::Success to indicate a successful operation.

In POSIX systems, the current working directory is associated with each process and can be changed using the chdir() system call. The chdir() function allows applications to switch to a different directory within the file system, which affects all subsequent file operations performed by the process.