pfdirs - Find Program Files folders in several ways

This is Rust program that reports information from multiple sources about where program files directories are located on a Windows system.

License

0BSD

Sources of information

Details on the source of information, including on subtleties of availability across process and system architectures, are provided in the code on the four report_* functions that access them. This is a brief summary of the functions:

• report_environment_variables() uses the ProgramFiles, ProgramFilesW6432, ProgramFiles(x86), and ProgramFiles(ARM) environment variables.

  It calls std::env::var() which, on Windows, itself internally calls the GetEnvironmentVariableW function.

• report_known_folders() uses the ProgramFiles, ProgramFilesX64, ProgramFilesX86, and UserProgramFiles known folders. (See also these remarks.)

  It calls SHGetKnownFolderPath in the Windows API using the windows crate, which allows detailed errors to be reported, and for demonstration purposes also calls and checks those results against the get_known_folder_path() function provided by the known-folders crate, which is often sufficient.

• report_csidl() uses the CSIDL_PROGRAM_FILES and CSIDL_PROGRAM_FILESX86 CSIDLs, though this should not usually be done because CSIDLs are superseded by known folders.

  It calls SHGetFolderPathW in the Windows API using the windows crate.

• report_all_registry_views() (see also report_registry_view()) uses the ProgramFilesDir, ProgramW6432Dir, ProgramFilesDir (x86), and ProgramFilesDir (Arm) registry keys in HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion, showing their values when accessed through the default view of the registry that depends on the process architecture, as well as when explicitly specifying the 32-bit view with KEY_WOW64_32KEY or the 64-bit view with KEY_WOW64_64KEY.

  It calls RegKey::open_subkey_with_flags in the winreg crate, which itself calls the RegOpenKeyExW function.

Examples

A 32-bit (x86) process running on a 64-bit (x64) system

C:\Users\ek\source\repos\pfdirs [main ≡]> cargo run --target=i686-pc-windows-msvc
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.07s
     Running `target\i686-pc-windows-msvc\debug\pfdirs.exe`
Relevant environment variables:

  ProgramFiles       C:\Program Files (x86)
  ProgramFiles(Arm)  [environment variable not found]
  ProgramFiles(x86)  C:\Program Files (x86)
  ProgramW6432       C:\Program Files

Relevant known folders:

  FOLDERID_ProgramFiles      C:\Program Files (x86)
  FOLDERID_ProgramFilesX64   [The system cannot find the file specified. (0x80070002)]
  FOLDERID_ProgramFilesX86   C:\Program Files (x86)
  FOLDERID_UserProgramFiles  C:\Users\ek\AppData\Local\Programs

Relevant CSIDLs:

  CSIDL_PROGRAM_FILES     C:\Program Files (x86)
  CSIDL_PROGRAM_FILESX86  C:\Program Files (x86)

Relevant registry keys - with default view:

  ProgramFilesDir        C:\Program Files (x86)
  ProgramFilesDir (Arm)  [The system cannot find the file specified. (os error 2)]
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files

Relevant registry keys - with KEY_WOW64_32KEY:

  ProgramFilesDir        C:\Program Files (x86)
  ProgramFilesDir (Arm)  [The system cannot find the file specified. (os error 2)]
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files

Relevant registry keys - with KEY_WOW64_64KEY:

  ProgramFilesDir        C:\Program Files
  ProgramFilesDir (Arm)  [The system cannot find the file specified. (os error 2)]
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files

This shows, among other things, that, as documented, the ProgramFilesX64 known folder information is not available to a 32-bit process, even when it is running on a 64-bit system.

An ARM64 process running natively on an ARM64 system

PS C:\Users\pickens\repos\pfdirs> cargo run
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.06s
     Running `target\debug\pfdirs.exe`
Relevant environment variables:

  ProgramFiles       C:\Program Files
  ProgramFiles(Arm)  C:\Program Files (Arm)
  ProgramFiles(x86)  C:\Program Files (x86)
  ProgramW6432       C:\Program Files

Relevant known folders:

  FOLDERID_ProgramFiles      C:\Program Files
  FOLDERID_ProgramFilesX64   C:\Program Files
  FOLDERID_ProgramFilesX86   C:\Program Files (x86)
  FOLDERID_UserProgramFiles  C:\Users\pickens\AppData\Local\Programs

Relevant CSIDLs:

  CSIDL_PROGRAM_FILES     C:\Program Files
  CSIDL_PROGRAM_FILESX86  C:\Program Files (x86)

Relevant registry keys - with default view:

  ProgramFilesDir        C:\Program Files
  ProgramFilesDir (Arm)  C:\Program Files (Arm)
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files

Relevant registry keys - with KEY_WOW64_32KEY:

  ProgramFilesDir        C:\Program Files (x86)
  ProgramFilesDir (Arm)  [The system cannot find the file specified. (os error 2)]
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files

Relevant registry keys - with KEY_WOW64_64KEY:

  ProgramFilesDir        C:\Program Files
  ProgramFilesDir (Arm)  C:\Program Files (Arm)
  ProgramFilesDir (x86)  C:\Program Files (x86)
  ProgramW6432Dir        C:\Program Files