getcwd()

Returns the current working directory.

Description

The getcwd() function retrieves the current working directory of the process. It returns the absolute path of the current working directory.

In POSIX systems, the current working directory represents the directory in the file system from which the process is currently executing. It is important for applications to know their current working directory to locate files and navigate the file system.

If the size of the buffer provided for the path is insufficient to hold the entire path, the function returns ERANGE to indicate that the path has been truncated. This allows the caller to allocate a larger buffer and call the function again to retrieve the full path.

Syntax

  ;;; will fill the path_len with the needed size and return EOVERFLOW
  ;;; If the path exceeds the size of the buffer then this function
  ;;;
  ;;; Returns the current working directory
  (@interface func (export "getcwd")
    ;;; The buffer where current directory is stored
    (param $path (@witx pointer u8))
    (param $path_len (@witx pointer $pointersize))
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: The function environment.
• path: A pointer to a buffer where the current working directory path will be written.
• path_len: A pointer to a variable that holds the size of the buffer in bytes.

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 provided buffer is too small to hold the entire path, it returns Errno::Range.

Logging

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

• path: The current working directory path.
• max_path_len: The maximum length of the path buffer.

Note

• The getcwd() function retrieves the current working directory of the process.
• It first gets the current directory path from the WASI state.
• The function then checks if the provided path buffer has enough space to hold the entire path. If not, it returns Errno::Range.
• If the buffer size is sufficient, it writes the current directory path to the buffer and returns Errno::Success.
• If the provided path pointer is null or the path_len is zero, the function returns Errno::Inval.

In POSIX systems, the current working directory is associated with each process and can be changed using the chdir() system call. It allows processes to have a different working directory from the directory in which they were started. The getcwd() function is part of the POSIX standard and provides a way to retrieve the current working directory of a process. It helps applications to determine their current location in the file system hierarchy and perform file operations relative to that directory.