gen/getttyent.3

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  32 .\"     @(#)getttyent.3 8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/getttyent.3,v 1.12 2001/10/01 16:08:51 ru Exp $
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  35 .Dd November 17, 1996
  36 .Dt GETTTYENT 3
  37 .Os
  38 .Sh NAME
  39 .Nm getttyent ,
  40 .Nm getttynam ,
  41 .Nm setttyent ,
  42 .Nm endttyent
  43 .Nd get ttys file entry
  44 .Sh LIBRARY
  45 .Lb libc
  46 .Sh SYNOPSIS
  47 .In ttyent.h
  48 .Ft struct ttyent *
  49 .Fn getttyent void
  50 .Ft struct ttyent *
  51 .Fn getttynam "const char *name"
  52 .Ft int
  53 .Fn setttyent void
  54 .Ft int
  55 .Fn endttyent void
  56 .Sh DESCRIPTION
  57 The
  58 .Fn getttyent ,
  59 and
  60 .Fn getttynam
  61 functions
  62 each return a pointer to an object, with the following structure,
  63 containing the broken-out fields of a line from the tty description
  64 file.
  65 .Bd -literal
  66 struct ttyent {
  67         char    *ty_name;       /* terminal device name */
  68         char    *ty_getty;      /* command to execute, usually getty */
  69         char    *ty_type;       /* terminal type for termcap */
  70 #define TTY_ON          0x01    /* enable logins (start ty_getty program) */
  71 #define TTY_SECURE      0x02    /* allow uid of 0 to login */
  72 #define TTY_DIALUP      0x04    /* is a dialup tty */
  73 #define TTY_NETWORK     0x08    /* is a network tty */
  74         int     ty_status;      /* status flags */
  75         char    *ty_window;     /* command to start up window manager */
  76         char    *ty_comment;    /* comment field */
  77         char    *ty_group;      /* tty group name */
  78 };
  79 .Ed
  80 .Pp
  81 The fields are as follows:
  82 .Bl -tag -width ty_comment
  83 .It Fa ty_name
  84 The name of the character-special file.
  85 .It Fa ty_getty
  86 The name of the command invoked
  87 to initialize tty line characteristics.
  88 .It Fa ty_type
  89 The name of the default terminal type connected to this tty line.
  90 .It Fa ty_status
  91 A mask of bit fields which indicate various actions allowed on this
  92 tty line.
  93 The possible flags are as follows:
  94 .Bl -tag -width TTY_NETWORK
  95 .It Dv TTY_ON
  96 Enables logins
  97 .It Dv TTY_SECURE
  98 Allow users with a uid of 0 to login on this terminal.
  99 .It Dv TTY_DIALUP
 100 Identifies a tty as a dialin line.
 101 .It Dv TTY_NETWORK
 102 Identifies a tty used for network connections.
 103 .El
 104 .It Fa ty_window
 105 The command to execute for a window system associated with the line.
 106 .It Fa ty_group
 107 A group name to which the tty belongs.
 108 If no group is specified in the ttys description file,
 109 then the tty is placed in an anonymous group called "none".
 110 .It Fa ty_comment
 111 Any trailing comment field, with any leading hash marks (``#'') or
 112 whitespace removed.
 113 .El
 114 .Pp
 115 If any of the fields pointing to character strings are unspecified,
 116 they are returned as null pointers.
 117 The field
 118 .Fa ty_status
 119 will be zero if no flag values are specified.
 120 .Pp
 121 See
 122 .Xr ttys 5
 123 for a more complete discussion of the meaning and usage of the
 124 fields.
 125 .Pp
 126 The
 127 .Fn getttyent
 128 function
 129 reads the next line from the ttys file, opening the file if necessary.
 130 The
 131 .Fn setttyent
 132 function
 133 rewinds the file if open, or opens the file if it is unopened.
 134 The
 135 .Fn endttyent
 136 function
 137 closes any open files.
 138 .Pp
 139 The
 140 .Fn getttynam
 141 function
 142 searches from the beginning of the file until a matching
 143 .Fa name
 144 is found
 145 (or until
 146 .Dv EOF
 147 is encountered).
 148 .Sh RETURN VALUES
 149 The routines
 150 .Fn getttyent
 151 and
 152 .Fn getttynam
 153 return a null pointer on
 154 .Dv EOF
 155 or error.
 156 The
 157 .Fn setttyent
 158 function
 159 and
 160 .Fn endttyent
 161 return 0 on failure and 1 on success.
 162 .Sh FILES
 163 .Bl -tag -width /etc/ttys -compact
 164 .It Pa /etc/ttys
 165 .El
 166 .Sh SEE ALSO
 167 .Xr login 1 ,
 168 .Xr ttyslot 3 ,
 169 .Xr gettytab 5 ,
 170 .Xr termcap 5 ,
 171 .Xr ttys 5 ,
 172 .Xr getty 8 ,
 173 .Sh HISTORY
 174 The
 175 .Fn getttyent ,
 176 .Fn getttynam ,
 177 .Fn setttyent ,
 178 and
 179 .Fn endttyent
 180 functions appeared in
 181 .Bx 4.3 .
 182 .Sh BUGS
 183 These functions use static data storage;
 184 if the data is needed for future use, it should be
 185 copied before any subsequent calls overwrite it.