Open file ntcreate

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See smbd/open.c/open_file_ntcreate.

The function implements NTCreate & X operation (create, open, overwrite file, check access right, etc) in smbd. It converts SMB parameters (open mode flags, sharing flags, etc) to UNIX parameters used in unix open call, checks share access to the file, obtains exclusive access to it and makes UNIX open operation.

Function arguments

  1. conn - current connection
  2. psbuf - stat-structure of the file (may be invalid for a new file)
  3. fname - file name
  4. access_mask - file access mask:
    • DELETE - file can be deleted
    • FILE_APPEND_DATA - appending (for directory - creating subdirectories)
    • FILE_READ_DATA - reading
    • FILE_WRITE_DATA - writing
    • FILE_EXECUTE - executing
    • SYNCHRONIZE - synchonize all IO operations on the returned handle
    • FILE_READ_ATTRIBUTES - file attributes can be read
    • FILE_WRITE_ATTRIBUTES - file attributes can can be written
    • ...
  5. share_access - file shared access mode:
    • FILE_SHARE_NONE - sharing disabled
    • FILE_SHARE_DELETE - enables delete access for open files
    • FILE_SHARE_READ - shared read access
    • FILE_SHARE_WRITE - shared write access
  6. create_disposition - an action to take on files (if they exist or don't exist):
    • FILE_SUPERSEDE - if the file already exists, replace it with the given file. If it does not, create the given file
    • FILE_CREATE - if the file already exists, fail the request and do not create or open the given file. If it does not, create the given file
    • FILE_OPEN - if the file already exists, open it instead of creating a new file. If it does not, fail the request and do not create a new file
    • FILE_OPEN_IF - if the file already exists, open it. If it does not, create the given file
    • FILE_OVERWRITE - if the file already exists, open it and overwrite it. If it does not, fail the request
    • FILE_OVERWRITE_IF - if the file already exists, open it and overwrite it. If it does not, create the given file create_options - options of file creation:
    • FILE_DIRECTORY_FILE - the file being created or opened is a directory file
    • FILE_NON_DIRECTORY_FILE - the file being opened must not be a directory file or this call fails
    • FILE_WRITE_THROUGH - synchonous data transfer
    • FILE_SEQUENTIAL_ONLY - all accesses to the file are sequential
    • FILE_RANDOM_ACCESS - accesses to the file can be random
    • FILE_NO_INTERMEDIATE_BUFFERING - the file cannot be cached or buffered in a driver's internal buffers
    • FILE_DELETE_ON_CLOSE - delete the file when the last handle to it is passed to NtClose
  7. oplock_request - opportunistic lock, used with connection
  8. pinfo - points to a variable that receives the final completion status of the operation:
    • FILE_CREATED - file was created
    • FILE_OPENED - file was opened
    • FILE_OVERWRITTEN - file was overwritten
    • FILE_SUPERSEDED - file was superseded
    • FILE_EXISTS - error: file exists
    • FILE_DOES_NOT_EXIST - error: file doesn't exist

Fuction local variables

  • flags (for file io) & flags2 (for file creation) - flags used for UNIX open file function (O_CREATE, O_TRUNC, etc)
  • file_existed - a flag: TRUE if file already exists
  • def_acl - a flag: TRUE if parent directory has default ACL
  • internal_only_open - a flag: TRUE if opportunistic lock (or deferring) is not used (file is opened for internal purposes)
  • dev & inode - device and inode number of the existed file
  • fsp_open - flag: TRUE if fsb was succesfully created (file was opened correctly)
  • fsp - file structure
  • new_unx_mode & unx_mode - dos file attributes projcted on the UNIX rights
  • info - variable with status of the file operation (see pinfo above)
  • existing_dos_attributes - dos file attributes
  • pml - current deferred smb messages list entry
  • mid - current smb message id
  • delayed_for_oplocks - flag: TRUE if message was delayed for oplock
  • request_time - time of the open request
  • lck - lock structure
  • status - NT Status of the share mode check operation

Program flow diagram

You can see program flow diagram in one PDF file: [1] or find SVG sources here - [2].

Call graph

Huge call graph of the function: [3]