1. 23 Jan, 2023 6 commits
    • Jeffrey Lee's avatar
      Protect the dynamic area · 46fb605d
      Jeffrey Lee authored
      The PipeFS dynamic area was being created with AP 0, granting usermode
      full read/write/execute access. Attempt to restrict it to just the
      minimum required permissions - privileged read/write for PipeFS access,
      and usermode read for TaskWindow (or other potential UpCall_Sleep
      handlers) checking pollwords.
      
      This isn't an ideal situation, both because we're exposing the contents
      to everyone, and because systems which are using the long descriptor
      page table format will be forced to use the kernel's AP1 emulation to
      provide usermode read access, adding unnecessary overhead to pollword
      checks.
      
      Moving the pollwords to the RMA could be one solution to this (although
      it will re-introducing the possibility for user code to scribble on
      them)
      
      Version 0.25. Tagged as 'PipeFS-0_25'
      46fb605d
    • Jeffrey Lee's avatar
      Fix fsfile_ReadInfo blockifwriting logic · c6b281a8
      Jeffrey Lee authored
      When handling fsfile_ReadInfo, PipeFS wants to wait for any writer to
      close the file before returning the file information. To do this it
      repeatedly calls FindFileOrDirectory & blockifwriting in a loop until
      that condition is reached (or the file ceases to exist). However the
      call to FindFileOrDirectory was replacing the filename in R1 with a the
      internal file handle (i.e. a pointer to a struct), so on the second loop
      round it would always exit out with a "file not found" response.
      
      This bug had the effect that attempting to read the size of a file (e.g.
      using OS_File 5 or *FileInfo) which is open for write would always
      report that the file doesn't exist, even if the blockifwriting call
      successfully blocks until the writer closes the file.
      
      Restoring R1 before looping back round will give the behaviour the
      programmer originally intended, for better or worse (e.g. current
      versions of FileSwitch use fsfile_ReadInfo to check the file before
      trying to open it, so trying to use OPENIN on a file which is open for
      write will unintentionally block - a bug that was hidden on earlier
      versions of RISC OS because prior to TaskWindow 0.65, TaskWindow didn't
      make any attempt to wait until the pollword was non-zero before
      returning, so PipeFS would pretty quickly exit out with a harmless "file
      not found" response due to the register corruption bug)
      c6b281a8
    • Jeffrey Lee's avatar
      Debug improvements · 57004a85
      Jeffrey Lee authored
      Add debug messages to all FS entry points, and call Debug_Open &
      Debug_Close
      57004a85
    • Jeffrey Lee's avatar
      Unblock reader when closing writer · ef85e431
      Jeffrey Lee authored
      This fixes a problem where a reader which is asleep waiting for more
      data to arrive won't be woken when the writer closes its end of the
      pipe.
      
      Behaviour 1:
      
      * Two taskwindows open the same pipe, one for reading, one for writing
      * Writer writes data to the pipe
      * Writer closes the pipe
      * Reader enters an OS_BGet loop to read until EOF
      
      Following the above steps, the reader will be able to read all of the
      data and the read loop will terminate.
      
      Behaviour 2:
      
      * Two taskwindows open the same pipe, one for reading, one for writing
      * Writer writes data to the pipe
      * Reader enters an OS_BGet loop to read until EOF
      * Wait for the reader to read all the data; it'll go to sleep waiting
      for more
      * Writer closes the pipe
      
      Following the above steps, the reader will remain asleep inside OS_BGet,
      even through the writer has signalled that it's finished with the pipe
      by closing it. This looks like a textbook race condition bug; if the
      writer closed the file with slightly different timing (e.g. while there
      are still unread bytes in the pipe, or while the pipe is empty but
      before the reader calls OS_BGet and is put to sleep) then the reader
      will behave correctly.
      
      This change fixes things so that any reader will be woken when the
      writer closes its end of the pipe.
      ef85e431
    • Jeffrey Lee's avatar
      Separate PipeFile_readblocked from PipeFile_Size · e0b768de
      Jeffrey Lee authored
      This separates the "reads blocked" pollword from the Size variable,
      without altering the behaviour. This is to allow for future changes
      which will alter the behaviour of the readblocked pollword.
      e0b768de
    • Jeffrey Lee's avatar
      af88fedb
  2. 08 Jun, 2018 1 commit
    • Robert Sprowson's avatar
      Delete some dead code · 7d614b57
      Robert Sprowson authored
      Since PipeFS registers with FileSwitch with both dontuseload and dontusesave there's no need to implement the corresponding FSEntry_File subreasons. This might have been left around because RISC OS 2 ignored FS info word flags b23-16, but we're not worrying about RISC OS 2 compatibility now.
      
      Version 0.24. Tagged as 'PipeFS-0_24'
      7d614b57
  3. 18 Aug, 2016 2 commits
    • Robert Sprowson's avatar
      Fix for NULL pointer access reporting monitor name · dea9b663
      Robert Sprowson authored
      PipeFS was carefully preserving R6 (the special field pointer, which is 0 for PipeFS) in the places where FileSwitch expects to get the leafname back when *OPT1,2 is enabled, resulting in a NULL pointer dereference in FileSwitch. Update R6 per the spec.
      Delete old switch justreturnextent from version 0.06.
      Delete unused Help & Syntax, these are now in Resources/UK.
      
      Version 0.23. Tagged as 'PipeFS-0_23'
      dea9b663
    • Robert Sprowson's avatar
      Clean up pass · d3452baf
      Robert Sprowson authored
      Use objasm {TRUE} and {FALSE}.
      Get error numbers from Hdr:NewErrors and file types from Hdr:FileTypes.
      Parameterise PipeFS_BufferSize and PipeFS_AllocSize.
      Deduce international_help switch locally since International_Help is a bitfield in Hdr:ModHand.
      Use Push/Pop macros.
      d3452baf
  4. 14 May, 2001 2 commits
    • Kevin Bracey's avatar
      Added "32-bit compatible" module flag. · 1b38b56e
      Kevin Bracey authored
      Version 0.22. Tagged as 'PipeFS-0_22'
      1b38b56e
    • Dan Ellis's avatar
      Fixed Sleep No More, and made 32-bit compatible. · 727584b9
      Dan Ellis authored
      Detail:
        PipeFS uses UpCall 6 (Sleep) to signal that the reading process can sleep,
      using the size of the file as a pollword.  Thus when any data is written into
      the pipe, the sleeping process will be woken up.  If an attempt is made to
      close the file handle, UpCall 7 (Sleep No More) is broadcast to allow anyone
      to object to the closure occurring.  Pipe_Close wasn't checking the error
      return from making this call, which was an error.  It will now propogate this
      error up to fileswitch upon an attempt being made to close the file while a
      process is sleeping on it.
      
        32-bitness involved changing a load of TEQPs for RestPSRs, and fixing some
      functions which had forgotten to use [sp, #Proc_RegOffset].
      
        Also added !Mk and added stripdepend to MkClean.
      
      Admin:
        Tested on dev board and RiscPC running a fairly recent Ursula build.
      Version 0.21. Tagged as 'PipeFS-0_21'
      727584b9
  5. 11 Apr, 2001 1 commit
    • David Cotton's avatar
      Converted to use ObjASM and shared makefiles. · 8523ee58
      David Cotton authored
      Detail:
          Converted to use ObjASM and shared makefiles. Added MkRes and MkExp obey
      files.
      
      Admin:
          Built. This module is *not* yet 32-bit compatible.
      
      Version 0.20. Tagged as 'PipeFS-0_20'
      8523ee58
  6. 22 Jan, 2001 1 commit
    • Andrew Hodgkinson's avatar
      File heap moved to private dynamic area; much more efficient UpCall generation. · 2dae69a3
      Andrew Hodgkinson authored
      Detail:
        Use of the RMA by PipeFS could lead to fragmentation, and is slower
        than a private dynamic area as the RMA's a very busy heap. The new
        dynamic area is set to 16MB maximum size, called "PipeFS", and the
        code is compile-time switched, not run-time.
      
        PipeFS has no block handling code so its get/put byte routines are
        called by the OS in a tight loop. Unfortunately for each byte it
        reads/writes it issues UpCall_ModifyingFile, and moreover does this
        without specifying a filename, so *all* directories are rescanned -
        for every single byte read or written to PipeFS. This is why PipeFS
        is so extremely slow prior to this version. Now, a callback is set,
        and the UpCall only issued when this goes off - after any block
        transfers, for example. A typical effect is a 171K file save from a
        text editor to PipeFS used to take around 20 seconds, and now takes
        less than a quarter of a second. Streaming data through PipeFS is
        now a sensible option.
      
        There are two variants of the callback code; one maintans an array
        of filename pointers and goes through the list each time the call-
        back fires; the other just issues a general UpCall each time. The
        first one should work OK, and is there in case anyone ever works
        out how to use R1 properly for the UpCall.
      Admin:
        Copied files into PipeFS up to the DA limit and verified sensible
        behaviour at this point; memory released as expected on file
        removal; files appear to be intact; MP3 streaming at 128kbps from
        network or disc through PipeFS is reliable; Filer window behaviour
        with "full info" on and Task Manager display of dynamic area size
        act as expected.
      
        By default, the compile-time options mean the module will only run on
        RISC OS 3.5 or later. Tested on RISC OS 3.70 only.
      
      Version 0.19. Tagged as 'PipeFS-0_19'
      2dae69a3
  7. 27 Aug, 1999 1 commit
    • Neil Bingham's avatar
      * Fixed mistake in makefile. · 2ab1d6f2
      Neil Bingham authored
      Detail
      ------
        * Under the resources: rule the dependency resources-{$CMDHELP} was
          spelt as resource-{$CMDHELP} which is not a valid dependency.
      Admin
      -----
        * Tested on Ursula build.
      
      Version 0.18. Tagged as 'PipeFS-0_18'
      2ab1d6f2
  8. 17 Aug, 1999 2 commits
  9. 21 Nov, 1996 1 commit
  10. 05 Nov, 1996 1 commit