| tty.4 (84306) | tty.4 (117011) |
|---|---|
| 1.\" Copyright (c) 1991, 1992, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)tty.4 8.3 (Berkeley) 4/19/94 | 1.\" Copyright (c) 1991, 1992, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)tty.4 8.3 (Berkeley) 4/19/94 |
| 33.\" $FreeBSD: head/share/man/man4/tty.4 84306 2001-10-01 16:09:29Z ru $ | 33.\" $FreeBSD: head/share/man/man4/tty.4 117011 2003-06-28 23:53:39Z ru $ |
| 34.\" 35.Dd August 14, 1992 36.Dt TTY 4 37.Os 38.Sh NAME 39.Nm tty 40.Nd general terminal interface 41.Sh SYNOPSIS --- 14 unchanged lines hidden (view full) --- 56a hardware terminal port, but to another program on the other side. 57These special terminal devices are called 58.Em ptys 59and provide the mechanism necessary to give users the same interface to the 60system when logging in over a network (using 61.Xr rlogin 1 , 62or 63.Xr telnet 1 | 34.\" 35.Dd August 14, 1992 36.Dt TTY 4 37.Os 38.Sh NAME 39.Nm tty 40.Nd general terminal interface 41.Sh SYNOPSIS --- 14 unchanged lines hidden (view full) --- 56a hardware terminal port, but to another program on the other side. 57These special terminal devices are called 58.Em ptys 59and provide the mechanism necessary to give users the same interface to the 60system when logging in over a network (using 61.Xr rlogin 1 , 62or 63.Xr telnet 1 |
| 64for example). Even in these cases the details of how the terminal | 64for example). 65Even in these cases the details of how the terminal |
| 65file was opened and set up is already handled by special software 66in the system. 67Thus, users do not normally need to worry about the details of | 66file was opened and set up is already handled by special software 67in the system. 68Thus, users do not normally need to worry about the details of |
| 68how these lines are opened or used. Also, these lines are often used | 69how these lines are opened or used. 70Also, these lines are often used |
| 69for dialing out of a system (through an out-calling modem), but again 70the system provides programs that hide the details of accessing 71these terminal special files (see 72.Xr tip 1 ) . 73.Pp 74When an interactive user logs in, the system prepares the line to 75behave in a certain way (called a 76.Em "line discipline" ) , 77the particular details of which is described in 78.Xr stty 1 79at the command level, and in 80.Xr termios 4 | 71for dialing out of a system (through an out-calling modem), but again 72the system provides programs that hide the details of accessing 73these terminal special files (see 74.Xr tip 1 ) . 75.Pp 76When an interactive user logs in, the system prepares the line to 77behave in a certain way (called a 78.Em "line discipline" ) , 79the particular details of which is described in 80.Xr stty 1 81at the command level, and in 82.Xr termios 4 |
| 81at the programming level. A user may be concerned with changing | 83at the programming level. 84A user may be concerned with changing |
| 82settings associated with his particular login terminal and should refer | 85settings associated with his particular login terminal and should refer |
| 83to the preceding man pages for the common cases. The remainder of 84this man page is concerned | 86to the preceding man pages for the common cases. 87The remainder of this man page is concerned |
| 85with describing details of using and controlling terminal devices 86at a low level, such as that possibly required by a program wishing 87to provide features similar to those provided by the system. 88.Ss Line disciplines 89A terminal file is used like any other file in the system in that 90it can be opened, read, and written to using standard system | 88with describing details of using and controlling terminal devices 89at a low level, such as that possibly required by a program wishing 90to provide features similar to those provided by the system. 91.Ss Line disciplines 92A terminal file is used like any other file in the system in that 93it can be opened, read, and written to using standard system |
| 91calls. For each existing terminal file, there is a software processing module | 94calls. 95For each existing terminal file, there is a software processing module |
| 92called a 93.Em "line discipline" 94is associated with it. The 95.Em "line discipline" 96essentially glues the low level device driver code with the high 97level generic interface routines (such as 98.Xr read 2 99and 100.Xr write 2 ) , 101and is responsible for implementing the semantics associated | 96called a 97.Em "line discipline" 98is associated with it. The 99.Em "line discipline" 100essentially glues the low level device driver code with the high 101level generic interface routines (such as 102.Xr read 2 103and 104.Xr write 2 ) , 105and is responsible for implementing the semantics associated |
| 102with the device. When a terminal file is first opened by a program, 103the default | 106with the device. 107When a terminal file is first opened by a program, the default |
| 104.Em "line discipline" 105called the 106.Dv termios | 108.Em "line discipline" 109called the 110.Dv termios |
| 107line discipline is associated with the file. This is the primary | 111line discipline is associated with the file. 112This is the primary |
| 108line discipline that is used in most cases and provides the semantics | 113line discipline that is used in most cases and provides the semantics |
| 109that users normally associate with a terminal. When the | 114that users normally associate with a terminal. 115When the |
| 110.Dv termios 111line discipline is in effect, the terminal file behaves and is 112operated according to the rules described in 113.Xr termios 4 . 114Please refer to that man page for a full description of the terminal 115semantics. 116The operations described here 117generally represent features common 118across all 119.Em "line disciplines" , 120however some of these calls may not 121make sense in conjunction with a line discipline other than 122.Dv termios , 123and some may not be supported by the underlying 124hardware (or lack thereof, as in the case of ptys). 125.Ss Terminal File Operations 126All of the following operations are invoked using the 127.Xr ioctl 2 | 116.Dv termios 117line discipline is in effect, the terminal file behaves and is 118operated according to the rules described in 119.Xr termios 4 . 120Please refer to that man page for a full description of the terminal 121semantics. 122The operations described here 123generally represent features common 124across all 125.Em "line disciplines" , 126however some of these calls may not 127make sense in conjunction with a line discipline other than 128.Dv termios , 129and some may not be supported by the underlying 130hardware (or lack thereof, as in the case of ptys). 131.Ss Terminal File Operations 132All of the following operations are invoked using the 133.Xr ioctl 2 |
| 128system call. Refer to that man page for a description of 129the | 134system call. 135Refer to that man page for a description of the |
| 130.Em request 131and 132.Em argp 133parameters. 134In addition to the ioctl 135.Em requests 136defined here, the specific line discipline 137in effect will define other 138.Em requests 139specific to it (actually 140.Xr termios 4 141defines them as function calls, not ioctl 142.Em requests . ) | 136.Em request 137and 138.Em argp 139parameters. 140In addition to the ioctl 141.Em requests 142defined here, the specific line discipline 143in effect will define other 144.Em requests 145specific to it (actually 146.Xr termios 4 147defines them as function calls, not ioctl 148.Em requests . ) |
| 143The following section lists the available ioctl requests. The 144name of the request, a description of its purpose, and the typed | 149The following section lists the available ioctl requests. 150The name of the request, a description of its purpose, and the typed |
| 145.Em argp 146parameter (if any) 147are listed. For example, the first entry says 148.Pp 149.D1 Em "TIOCSETD int *ldisc" 150.Pp 151and would be called on the terminal associated with 152file descriptor zero by the following code fragment: --- 87 unchanged lines hidden (view full) --- 240call with the 241.Dv TCSAFLUSH 242option. 243.It Dv TIOCOUTQ Fa int *num 244Place the current number of characters in the output queue in the 245integer pointed to by 246.Fa num . 247.It Dv TIOCSTI Fa char *cp | 151.Em argp 152parameter (if any) 153are listed. For example, the first entry says 154.Pp 155.D1 Em "TIOCSETD int *ldisc" 156.Pp 157and would be called on the terminal associated with 158file descriptor zero by the following code fragment: --- 87 unchanged lines hidden (view full) --- 246call with the 247.Dv TCSAFLUSH 248option. 249.It Dv TIOCOUTQ Fa int *num 250Place the current number of characters in the output queue in the 251integer pointed to by 252.Fa num . 253.It Dv TIOCSTI Fa char *cp |
| 248Simulate typed input. Pretend as if the terminal received the 249character pointed to by | 254Simulate typed input. 255Pretend as if the terminal received the character pointed to by |
| 250.Fa cp . 251.It Dv TIOCNOTTY Fa void | 256.Fa cp . 257.It Dv TIOCNOTTY Fa void |
| 252This call is obsolete but left for compatibility. In the past, when 253a process that didn't have a controlling terminal (see | 258This call is obsolete but left for compatibility. 259In the past, when a process that didn't have a controlling terminal (see |
| 254.Em The Controlling Terminal 255in 256.Xr termios 4 ) 257first opened a terminal device, it acquired that terminal as its | 260.Em The Controlling Terminal 261in 262.Xr termios 4 ) 263first opened a terminal device, it acquired that terminal as its |
| 258controlling terminal. For some programs this was a hazard as they | 264controlling terminal. 265For some programs this was a hazard as they |
| 259didn't want a controlling terminal in the first place, and this 260provided a mechanism to disassociate the controlling terminal from | 266didn't want a controlling terminal in the first place, and this 267provided a mechanism to disassociate the controlling terminal from |
| 261the calling process. It | 268the calling process. 269It |
| 262.Em must 263be called by opening the file 264.Pa /dev/tty 265and calling 266.Dv TIOCNOTTY 267on that file descriptor. 268.Pp 269The current system does not allocate a controlling terminal to 270a process on an 271.Fn open 272call: there is a specific ioctl called 273.Dv TIOSCTTY 274to make a terminal the controlling 275terminal. 276In addition, a program can 277.Fn fork 278and call the 279.Fn setsid 280system call which will place the process into its own session - which | 270.Em must 271be called by opening the file 272.Pa /dev/tty 273and calling 274.Dv TIOCNOTTY 275on that file descriptor. 276.Pp 277The current system does not allocate a controlling terminal to 278a process on an 279.Fn open 280call: there is a specific ioctl called 281.Dv TIOSCTTY 282to make a terminal the controlling 283terminal. 284In addition, a program can 285.Fn fork 286and call the 287.Fn setsid 288system call which will place the process into its own session - which |
| 281has the effect of disassociating it from the controlling terminal. This 282is the new and preferred method for programs to lose their controlling | 289has the effect of disassociating it from the controlling terminal. 290This is the new and preferred method for programs to lose their controlling |
| 283terminal. 284.It Dv TIOCSTOP Fa void 285Stop output on the terminal (like typing ^S at the keyboard). 286.It Dv TIOCSTART Fa void 287Start output on the terminal (like typing ^Q at the keyboard). 288.It Dv TIOCSCTTY Fa void 289Make the terminal the controlling terminal for the process (the process 290must not currently have a controlling terminal). 291.It Dv TIOCDRAIN Fa void 292Wait until all output is drained. 293.It Dv TIOCEXCL Fa void | 291terminal. 292.It Dv TIOCSTOP Fa void 293Stop output on the terminal (like typing ^S at the keyboard). 294.It Dv TIOCSTART Fa void 295Start output on the terminal (like typing ^Q at the keyboard). 296.It Dv TIOCSCTTY Fa void 297Make the terminal the controlling terminal for the process (the process 298must not currently have a controlling terminal). 299.It Dv TIOCDRAIN Fa void 300Wait until all output is drained. 301.It Dv TIOCEXCL Fa void |
| 294Set exclusive use on the terminal. No further opens are permitted 295except by root. Of course, this means that programs that are run by | 302Set exclusive use on the terminal. 303No further opens are permitted except by root. 304Of course, this means that programs that are run by |
| 296root (or setuid) will not obey the exclusive setting - which limits 297the usefulness of this feature. 298.It Dv TIOCNXCL Fa void | 305root (or setuid) will not obey the exclusive setting - which limits 306the usefulness of this feature. 307.It Dv TIOCNXCL Fa void |
| 299Clear exclusive use of the terminal. Further opens are permitted. | 308Clear exclusive use of the terminal. 309Further opens are permitted. |
| 300.It Dv TIOCFLUSH Fa int *what 301If the value of the int pointed to by 302.Fa what 303contains the 304.Dv FREAD 305bit as defined in 306.Aq Pa sys/file.h , | 310.It Dv TIOCFLUSH Fa int *what 311If the value of the int pointed to by 312.Fa what 313contains the 314.Dv FREAD 315bit as defined in 316.Aq Pa sys/file.h , |
| 307then all characters in the input queue are cleared. If it contains 308the | 317then all characters in the input queue are cleared. 318If it contains the |
| 309.Dv FWRITE | 319.Dv FWRITE |
| 310bit, then all characters in the output queue are cleared. If the 311value of the integer is zero, then it behaves as if both the | 320bit, then all characters in the output queue are cleared. 321If the value of the integer is zero, then it behaves as if both the |
| 312.Dv FREAD 313and 314.Dv FWRITE 315bits were set (i.e. clears both queues). 316.It Dv TIOCGWINSZ Fa struct winsize *ws 317Put the window size information associated with the terminal in the 318.Va winsize 319structure pointed to by 320.Fa ws . 321The window size structure contains the number of rows and columns (and pixels | 322.Dv FREAD 323and 324.Dv FWRITE 325bits were set (i.e. clears both queues). 326.It Dv TIOCGWINSZ Fa struct winsize *ws 327Put the window size information associated with the terminal in the 328.Va winsize 329structure pointed to by 330.Fa ws . 331The window size structure contains the number of rows and columns (and pixels |
| 322if appropriate) of the devices attached to the terminal. It is set by user software | 332if appropriate) of the devices attached to the terminal. 333It is set by user software |
| 323and is the means by which most full\&-screen oriented programs determine the | 334and is the means by which most full\&-screen oriented programs determine the |
| 324screen size. The | 335screen size. 336The |
| 325.Va winsize 326structure is defined in 327.Aq Pa sys/ioctl.h . 328.It Dv TIOCSWINSZ Fa struct winsize *ws 329Set the window size associated with the terminal to be the value in 330the 331.Va winsize 332structure pointed to by 333.Fa ws 334(see above). 335.It Dv TIOCCONS Fa int *on 336If 337.Fa on 338points to a non-zero integer, redirect kernel console output (kernel printf's) 339to this terminal. 340If 341.Fa on 342points to a zero integer, redirect kernel console output back to the normal | 337.Va winsize 338structure is defined in 339.Aq Pa sys/ioctl.h . 340.It Dv TIOCSWINSZ Fa struct winsize *ws 341Set the window size associated with the terminal to be the value in 342the 343.Va winsize 344structure pointed to by 345.Fa ws 346(see above). 347.It Dv TIOCCONS Fa int *on 348If 349.Fa on 350points to a non-zero integer, redirect kernel console output (kernel printf's) 351to this terminal. 352If 353.Fa on 354points to a zero integer, redirect kernel console output back to the normal |
| 343console. This is usually used on workstations to redirect kernel messages | 355console. 356This is usually used on workstations to redirect kernel messages |
| 344to a particular window. 345.It Dv TIOCMSET Fa int *state 346The integer pointed to by 347.Fa state | 357to a particular window. 358.It Dv TIOCMSET Fa int *state 359The integer pointed to by 360.Fa state |
| 348contains bits that correspond to modem state. Following is a list 349of defined variables and the modem state they represent: | 361contains bits that correspond to modem state. 362Following is a list of defined variables and the modem state they represent: |
| 350.Pp 351.Bl -tag -width TIOCMXCTS -compact 352.It TIOCM_LE 353Line Enable. 354.It TIOCM_DTR 355Data Terminal Ready. 356.It TIOCM_RTS 357Request To Send. --- 55 unchanged lines hidden --- | 363.Pp 364.Bl -tag -width TIOCMXCTS -compact 365.It TIOCM_LE 366Line Enable. 367.It TIOCM_DTR 368Data Terminal Ready. 369.It TIOCM_RTS 370Request To Send. --- 55 unchanged lines hidden --- |