cvs commit: src/sys/kern tty_pts.c

[Ed Schouten]

ed          2008-08-22 10:40:21 UTC

  FreeBSD src repository

  Modified files:
    sys/kern             tty_pts.c 
  Log:
  SVN rev 182001 on 2008-08-22 10:40:21Z by ed
  
  Fix pts(4) error codes when slave device is closed.
  
  Unlike pre-MPSAFE TTY, the pts(4) driver always returned ENXIO when a
  read() or write() was performed on a pseudo-terminal master device when
  the slave device was not opened. The old implementation had different
  semantics:
  
  - When the slave device had not been opened yet, read() and write() just
    blocked.
  - When the slave device had been closed, a read() call would return 0
    bytes length.
  - When the slave device had been closed, a write() call would return
    EIO.
  
  Change the new implementation to return 0 and EIO as well. We don't
  implement the first rule, but I suspect this is not needed, because
  routines like openpty() also open the slave device node. posix_openpt()
  users also do similar things.
  
  Reported by:    rink
  Tested by:      rink
  
  Revision  Changes    Path
  1.20      +2 -4      src/sys/kern/tty_pts.c