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OpenSolaris 2009.06 - man page for ttysrch (opensolaris section 4)

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ttysrch(4)				   File Formats 			       ttysrch(4)

       ttysrch - directory search list for ttyname

       ttysrch	is  an	optional file that is used by the ttyname library routine. This file con-
       tains the names of directories in /dev that contain terminal and  terminal-related  device
       files.  The  purpose  of  this file is to improve the performance of ttyname by indicating
       which subdirectories in /dev contain terminal-related device files and should be  searched
       first.  These  subdirectory  names must appear on separate lines and must begin with /dev.
       Those path names that do not begin with /dev will be ignored and a warning will be sent to
       the  console. Blank lines (lines containing only white space) and lines beginning with the
       comment character "#" will be ignored. For each file listed (except for the special  entry
       /dev), ttyname will recursively search through subdirectories looking for a match. If /dev
       appears in the ttysrch file, the /dev directory itself will be searched but there will not
       be a recursive search through its subdirectories.

       When  ttyname searches through the device files, it tries to find a file whose major/minor
       device number, file system identifier, and inode number match that of the file  descriptor
       it  was	given as an argument. If a match is not found, it will settle for a match of just
       major/minor device and file system identifier, if one can be found. However, if	the  file
       descriptor  is  associated  with a cloned device, this algorithm does not work efficiently
       because the inode number  of the device file associated with a clonable device will  never
       match  the inode number of the file descriptor that was returned by the open of that clon-
       able device. To help with these situations, entries can be put into the /etc/ttysrch  file
       to  improve  performance when cloned devices are used as terminals  on a system (for exam-
       ple, for remote login). However, this is only useful if the minor  devices  related  to	a
       cloned device are put into a subdirectory. (It is important to note that device files need
       not exist for cloned devices and if that is the case, ttyname will  eventually  fail.)  An
       optional  second field is used in the /etc/ttysrch file to indicate the matching criteria.
       This field is separated by white space (any combination of blanks or tabs). The	letter	M
       means major/minor device number, F means file system identifier, and I means inode number.
       If this field is not specified for an entry, the default is MFI which means try	to  match
       on  all	three.	For cloned devices the field should be MF, which indicates that it is not
       necessary to match on the inode number.

       Without the /etc/ttysrch file, ttyname will search the /dev directory by first looking  in
       the  directories  /dev/term,  /dev/pts,	and  /dev/xt.  If  a  system has terminal devices
       installed in directories other than these, it may help performance if the ttysrch file  is
       created and contains that list of directories.

       Example 1 A sample display of /etc/ttysrch command.

       A sample /etc/ttysrch file follows:

	 /dev/term     MFI
	 /dev/pts      MFI
	 /dev/xt       MFI
	 /dev/slan     MF

       This file tells	ttyname that it should first search through those directories listed  and
       that when searching through the /dev/slan  directory,  if  a  file  is  encountered  whose
       major/minor  devices and file system identifier match that of the file descriptor argument
       to ttyname, this device name should be considered a match.



SunOS 5.11				   23 Feb 1994				       ttysrch(4)
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