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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 contains 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 clonable
       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 example, 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 5.9                         23 Feb 1994                       ttysrch(4)


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