From cc3116a9380fe32a751b584f3d8083698ccfba15 Mon Sep 17 00:00:00 2001 From: ed Date: Wed, 20 Aug 2008 08:31:58 +0000 Subject: Integrate the new MPSAFE TTY layer to the FreeBSD operating system. The last half year I've been working on a replacement TTY layer for the FreeBSD kernel. The new TTY layer was designed to improve the following: - Improved driver model: The old TTY layer has a driver model that is not abstract enough to make it friendly to use. A good example is the output path, where the device drivers directly access the output buffers. This means that an in-kernel PPP implementation must always convert network buffers into TTY buffers. If a PPP implementation would be built on top of the new TTY layer (still needs a hooks layer, though), it would allow the PPP implementation to directly hand the data to the TTY driver. - Improved hotplugging: With the old TTY layer, it isn't entirely safe to destroy TTY's from the system. This implementation has a two-step destructing design, where the driver first abandons the TTY. After all threads have left the TTY, the TTY layer calls a routine in the driver, which can be used to free resources (unit numbers, etc). The pts(4) driver also implements this feature, which means posix_openpt() will now return PTY's that are created on the fly. - Improved performance: One of the major improvements is the per-TTY mutex, which is expected to improve scalability when compared to the old Giant locking. Another change is the unbuffered copying to userspace, which is both used on TTY device nodes and PTY masters. Upgrading should be quite straightforward. Unlike previous versions, existing kernel configuration files do not need to be changed, except when they reference device drivers that are listed in UPDATING. Obtained from: //depot/projects/mpsafetty/... Approved by: philip (ex-mentor) Discussed: on the lists, at BSDCan, at the DevSummit Sponsored by: Snow B.V., the Netherlands dcons(4) fixed by: kan --- lib/libc/stdlib/Makefile.inc | 12 +-- lib/libc/stdlib/Symbol.map | 1 - lib/libc/stdlib/grantpt.3 | 225 ------------------------------------------- lib/libc/stdlib/ptsname.3 | 160 ++++++++++++++++++++++++++++++ lib/libc/stdlib/ptsname.c | 95 ++++++++++++++++++ lib/libc/sys/Makefile.inc | 4 +- lib/libc/sys/Symbol.map | 1 + lib/libc/sys/getrlimit.2 | 4 +- lib/libc/sys/posix_openpt.2 | 135 ++++++++++++++++++++++++++ 9 files changed, 402 insertions(+), 235 deletions(-) delete mode 100644 lib/libc/stdlib/grantpt.3 create mode 100644 lib/libc/stdlib/ptsname.3 create mode 100644 lib/libc/stdlib/ptsname.c create mode 100644 lib/libc/sys/posix_openpt.2 (limited to 'lib/libc') diff --git a/lib/libc/stdlib/Makefile.inc b/lib/libc/stdlib/Makefile.inc index f9b8fec..86b3c65 100644 --- a/lib/libc/stdlib/Makefile.inc +++ b/lib/libc/stdlib/Makefile.inc @@ -6,9 +6,9 @@ MISRCS+=_Exit.c a64l.c abort.c abs.c atexit.c atof.c atoi.c atol.c atoll.c \ bsearch.c div.c exit.c getenv.c getopt.c getopt_long.c \ - getsubopt.c grantpt.c hcreate.c heapsort.c imaxabs.c imaxdiv.c \ + getsubopt.c hcreate.c heapsort.c imaxabs.c imaxdiv.c \ insque.c l64a.c labs.c ldiv.c llabs.c lldiv.c lsearch.c malloc.c \ - merge.c qsort.c qsort_r.c radixsort.c rand.c random.c \ + merge.c ptsname.c qsort.c qsort_r.c radixsort.c rand.c random.c \ reallocf.c realpath.c remque.c strfmon.c strtoimax.c \ strtol.c strtoll.c strtoq.c strtoul.c strtonum.c strtoull.c \ strtoumax.c strtouq.c system.c tdelete.c tfind.c tsearch.c twalk.c @@ -21,10 +21,10 @@ SYM_MAPS+= ${.CURDIR}/stdlib/Symbol.map .endif MAN+= a64l.3 abort.3 abs.3 alloca.3 atexit.3 atof.3 atoi.3 atol.3 bsearch.3 \ - div.3 exit.3 getenv.3 getopt.3 getopt_long.3 getsubopt.3 grantpt.3 \ + div.3 exit.3 getenv.3 getopt.3 getopt_long.3 getsubopt.3 \ hcreate.3 imaxabs.3 imaxdiv.3 insque.3 labs.3 ldiv.3 llabs.3 lldiv.3 \ - lsearch.3 malloc.3 memory.3 posix_memalign.3 qsort.3 radixsort.3 \ - rand.3 random.3 \ + lsearch.3 malloc.3 memory.3 posix_memalign.3 ptsname.3 qsort.3 \ + radixsort.3 rand.3 random.3 \ realpath.3 strfmon.3 strtod.3 strtol.3 strtonum.3 strtoul.3 system.3 \ tsearch.3 @@ -33,10 +33,10 @@ MLINKS+=atol.3 atoll.3 MLINKS+=exit.3 _Exit.3 MLINKS+=getenv.3 putenv.3 getenv.3 setenv.3 getenv.3 unsetenv.3 MLINKS+=getopt_long.3 getopt_long_only.3 -MLINKS+=grantpt.3 posix_openpt.3 grantpt.3 ptsname.3 grantpt.3 unlockpt.3 MLINKS+=hcreate.3 hdestroy.3 hcreate.3 hsearch.3 MLINKS+=insque.3 remque.3 MLINKS+=lsearch.3 lfind.3 +MLINKS+=ptsname.3 grantpt.3 ptsname.3 unlockpt.3 MLINKS+=qsort.3 heapsort.3 qsort.3 mergesort.3 qsort.3 qsort_r.3 MLINKS+=rand.3 rand_r.3 rand.3 srand.3 rand.3 sranddev.3 MLINKS+=random.3 initstate.3 random.3 setstate.3 random.3 srandom.3 \ diff --git a/lib/libc/stdlib/Symbol.map b/lib/libc/stdlib/Symbol.map index 23cb391..10dff7e 100644 --- a/lib/libc/stdlib/Symbol.map +++ b/lib/libc/stdlib/Symbol.map @@ -30,7 +30,6 @@ FBSD_1.0 { suboptarg; getsubopt; grantpt; - posix_openpt; ptsname; unlockpt; hcreate; diff --git a/lib/libc/stdlib/grantpt.3 b/lib/libc/stdlib/grantpt.3 deleted file mode 100644 index b4ad8c4..0000000 --- a/lib/libc/stdlib/grantpt.3 +++ /dev/null @@ -1,225 +0,0 @@ -.\" -.\" Copyright (c) 2002 The FreeBSD Project, Inc. -.\" All rights reserved. -.\" -.\" This software includes code contributed to the FreeBSD Project -.\" by Ryan Younce of North Carolina State University. -.\" -.\" Redistribution and use in source and binary forms, with or without -.\" modification, are permitted provided that the following conditions -.\" are met: -.\" 1. Redistributions of source code must retain the above copyright -.\" notice, this list of conditions and the following disclaimer. -.\" 2. Redistributions in binary form must reproduce the above copyright -.\" notice, this list of conditions and the following disclaimer in the -.\" documentation and/or other materials provided with the distribution. -.\" 3. Neither the name of the FreeBSD Project nor the names of its -.\" contributors may be used to endorse or promote products derived from -.\" this software without specific prior written permission. -.\" -.\" THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT AND CONTRIBUTORS -.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A -.\" PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FREEBSD PROJECT -.\" OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED -.\" TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR -.\" PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF -.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING -.\" NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS -.\" SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -.\" -.\" $FreeBSD$ -.\" -.Dd December 23, 2002 -.Os -.Dt GRANTPT 3 -.Sh NAME -.Nm grantpt , -.Nm ptsname , -.Nm unlockpt , -.Nm posix_openpt -.Nd pseudo-terminal access functions -.Sh LIBRARY -.Lb libc -.Sh SYNOPSIS -.In stdlib.h -.Ft int -.Fn grantpt "int fildes" -.Ft "char *" -.Fn ptsname "int fildes" -.Ft int -.Fn unlockpt "int fildes" -.In fcntl.h -.Ft int -.Fn posix_openpt "int mode" -.Sh DESCRIPTION -The -.Fn grantpt , -.Fn ptsname , -.Fn unlockpt , -and -.Fn posix_openpt -functions allow access to pseudo-terminal devices. -The first three functions accept a file descriptor -that references the master half of a pseudo-terminal pair. -This file descriptor is created with -.Fn posix_openpt . -.Pp -The -.Fn grantpt -function is used to establish ownership and permissions -of the slave device counterpart to the master device -specified with -.Fa fildes . -The slave device's ownership is set to the real user ID -of the calling process, and the permissions are set to -user readable-writable and group writable. -The group owner of the slave device is also set to the -group -.Dq Li tty -if it exists on the system; otherwise, it -is left untouched. -.Pp -The -.Fn ptsname -function returns the full pathname of the slave device -counterpart to the master device specified with -.Fa fildes . -This value can be used -to subsequently open the appropriate slave after -.Fn posix_openpt -and -.Fn grantpt -have been called. -.Pp -The -.Fn unlockpt -function clears the lock held on the pseudo-terminal pair -for the master device specified with -.Fa fildes . -.Pp -The -.Fn posix_openpt -function opens the first available master pseudo-terminal -device and returns a descriptor to it. -The -.Fa mode -argument -specifies the flags used for opening the device: -.Bl -tag -width ".Dv O_NOCTTY" -.It Dv O_RDWR -Open for reading and writing. -.It Dv O_NOCTTY -If set, do not allow the terminal to become -the controlling terminal for the calling process. -.El -.Sh RETURN VALUES -.Rv -std grantpt unlockpt -.Pp -The -.Fn ptsname -function returns a pointer to the name -of the slave device on success; otherwise a -.Dv NULL -pointer is returned and the global variable -.Va errno -is set to indicate the error. -.Pp -The -.Fn posix_openpt -function returns a file descriptor to the first -available master pseudo-terminal device on success; -otherwise \-1 is returned and the global variable -.Va errno -is set to indicate the error. -.Sh ERRORS -The -.Fn grantpt , -.Fn ptsname , -and -.Fn unlockpt -functions may fail and set -.Va errno -to: -.Bl -tag -width Er -.It Bq Er EINVAL -.Fa fildes -is not a master pseudo-terminal device. -.El -.Pp -In addition, the -.Fn grantpt -function may set -.Va errno -to: -.Bl -tag -width Er -.It Bq Er EACCES -The slave pseudo-terminal device could not be accessed. -.El -.Pp -The -.Fn posix_openpt -function may fail and set -.Va errno -to: -.Bl -tag -width Er -.It Bq Er EINVAL -.Fa mode -consists of an invalid mode bit. -.It Bq Er EAGAIN -The system has no available pseudo-terminal devices. -.El -.Pp -The -.Fn grantpt , -.Fn ptsname , -and -.Fn unlockpt -functions may also fail and set -.Va errno -for any of the errors specified for the -.Xr fstat 2 -system call. -.Pp -The -.Fn posix_openpt -function may also fail and set -.Va errno -for any of the errors specified for the -.Xr open 2 -system call. -.Sh SEE ALSO -.Xr open 2 , -.Xr pty 4 , -.Xr tty 4 -.Sh STANDARDS -The -.Fn grantpt , -.Fn ptsname , -.Fn unlockpt , -and -.Fn posix_openpt -functions conform to -.St -p1003.1-2001 . -.Sh HISTORY -The -.Fn grantpt , -.Fn ptsname , -.Fn unlockpt , -and -.Fn posix_openpt -functions appeared in -.Fx 5.0 . -.Sh NOTES -The purpose of the -.Fn unlockpt -function has no meaning in -.Fx . -.Pp -The flag -.Dv O_NOCTTY -is included for compatibility; in -.Fx , -opening a terminal does not cause it to become -a process's controlling terminal. diff --git a/lib/libc/stdlib/ptsname.3 b/lib/libc/stdlib/ptsname.3 new file mode 100644 index 0000000..b9c7381 --- /dev/null +++ b/lib/libc/stdlib/ptsname.3 @@ -0,0 +1,160 @@ +.\" +.\" Copyright (c) 2002 The FreeBSD Project, Inc. +.\" All rights reserved. +.\" +.\" This software includes code contributed to the FreeBSD Project +.\" by Ryan Younce of North Carolina State University. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the FreeBSD Project nor the names of its +.\" contributors may be used to endorse or promote products derived from +.\" this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT AND CONTRIBUTORS +.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +.\" PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FREEBSD PROJECT +.\" OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED +.\" TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +.\" PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +.\" NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +.\" SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd August 20, 2008 +.Os +.Dt PTSNAME 3 +.Sh NAME +.Nm grantpt , +.Nm ptsname , +.Nm unlockpt +.Nd pseudo-terminal access functions +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In stdlib.h +.Ft int +.Fn grantpt "int fildes" +.Ft "char *" +.Fn ptsname "int fildes" +.Ft int +.Fn unlockpt "int fildes" +.Sh DESCRIPTION +The +.Fn grantpt , +.Fn ptsname , +and +.Fn unlockpt +functions allow access to pseudo-terminal devices. +These three functions accept a file descriptor that references the +master half of a pseudo-terminal pair. +This file descriptor is created with +.Xr posix_openpt 2 . +.Pp +The +.Fn grantpt +function is used to establish ownership and permissions +of the slave device counterpart to the master device +specified with +.Fa fildes . +The slave device's ownership is set to the real user ID +of the calling process, and the permissions are set to +user readable-writable and group writable. +The group owner of the slave device is also set to the +group +.Dq Li tty . +.Pp +The +.Fn ptsname +function returns the full pathname of the slave device +counterpart to the master device specified with +.Fa fildes . +This value can be used +to subsequently open the appropriate slave after +.Xr posix_openpt 2 +and +.Fn grantpt +have been called. +.Pp +The +.Fn unlockpt +function clears the lock held on the pseudo-terminal pair +for the master device specified with +.Fa fildes . +.Sh RETURN VALUES +.Rv -std grantpt unlockpt +.Pp +The +.Fn ptsname +function returns a pointer to the name +of the slave device on success; otherwise a +.Dv NULL +pointer is returned. +.Sh ERRORS +The +.Fn grantpt +and +.Fn unlockpt +functions may fail and set +.Va errno +to: +.Bl -tag -width Er +.It Bq Er EBADF +.Fa fildes +is not a valid open file descriptor. +.It Bq Er EINVAL +.Fa fildes +is not a master pseudo-terminal device. +.El +.Pp +In addition, the +.Fn grantpt +function may set +.Va errno +to: +.Bl -tag -width Er +.It Bq Er EACCES +The slave pseudo-terminal device could not be accessed. +.El +.Sh SEE ALSO +.Xr posix_openpt 2 , +.Xr pts 4 , +.Xr tty 4 +.Sh STANDARDS +The +.Fn grantpt , +.Fn ptsname +and +.Fn unlockpt +functions conform to +.St -p1003.1-2001 . +.Sh HISTORY +The +.Fn grantpt , +.Fn ptsname +and +.Fn unlockpt +functions appeared in +.Fx 5.0 . +.Sh NOTES +The purpose of the +.Fn grantpt +and +.Fn unlockpt +functions has no meaning in +.Fx , +because pseudo-terminals obtained by +.Xr posix_openpt 2 +are created on demand. +Because these devices are created with proper permissions in place, they +are guaranteed to be unused by unprivileged processes. diff --git a/lib/libc/stdlib/ptsname.c b/lib/libc/stdlib/ptsname.c new file mode 100644 index 0000000..fa606f6 --- /dev/null +++ b/lib/libc/stdlib/ptsname.c @@ -0,0 +1,95 @@ +/*- + * Copyright (c) 2008 Ed Schouten + * All rights reserved. + * + * Portions of this software were developed under sponsorship from Snow + * B.V., the Netherlands. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +#ifndef lint +__FBSDID("$FreeBSD$"); +#endif /* not lint */ + +#include "namespace.h" +#include +#include + +#include +#include +#include "un-namespace.h" + +/* + * __isptmaster(): return whether the file descriptor refers to a + * pseudo-terminal master device. + */ +static int +__isptmaster(int fildes) +{ + + if (_ioctl(fildes, TIOCPTMASTER) == 0) + return (0); + + if (errno != EBADF) + errno = EINVAL; + + return (-1); +} + +/* + * In our implementation, grantpt() and unlockpt() don't actually have + * any use, because PTY's are created on the fly and already have proper + * permissions upon creation. + * + * Just make sure `fildes' actually points to a real PTY master device. + */ +__strong_reference(__isptmaster, grantpt); +__strong_reference(__isptmaster, unlockpt); + +/* + * ptsname(): return the pathname of the slave pseudo-terminal device + * associated with the specified master. + */ +char * +ptsname(int fildes) +{ + static char pt_slave[sizeof _PATH_DEV + SPECNAMELEN] = _PATH_DEV; + struct fiodgname_arg fgn; + char *ret = NULL; + int sverrno = errno; + + /* Make sure fildes points to a master device. */ + if (__isptmaster(fildes) != 0) + goto done; + + /* Obtain the device name through FIODGNAME. */ + fgn.len = sizeof pt_slave - (sizeof _PATH_DEV - 1); + fgn.buf = pt_slave + (sizeof _PATH_DEV - 1); + if (_ioctl(fildes, FIODGNAME, &fgn) == 0) + ret = pt_slave; + +done: /* Make sure ptsname() does not overwrite errno. */ + errno = sverrno; + return (ret); +} diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc index 195fb1f..f84ce13 100644 --- a/lib/libc/sys/Makefile.inc +++ b/lib/libc/sys/Makefile.inc @@ -79,8 +79,8 @@ MAN+= abort2.2 accept.2 access.2 acct.2 adjtime.2 \ mlockall.2 mmap.2 modfind.2 modnext.2 modstat.2 mount.2 mprotect.2 \ mq_close.2 mq_getattr.2 mq_notify.2 mq_open.2 mq_receive.2 mq_send.2 \ mq_setattr.2 \ - msync.2 munmap.2 nanosleep.2 nfssvc.2 ntp_adjtime.2 \ - open.2 pathconf.2 pipe.2 poll.2 profil.2 ptrace.2 quotactl.2 \ + msync.2 munmap.2 nanosleep.2 nfssvc.2 ntp_adjtime.2 open.2 \ + pathconf.2 pipe.2 poll.2 posix_openpt.2 profil.2 ptrace.2 quotactl.2 \ read.2 readlink.2 reboot.2 recv.2 rename.2 revoke.2 rfork.2 rmdir.2 \ rtprio.2 .if !defined(NO_P1003_1B) diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map index d38f287..5217ab0 100644 --- a/lib/libc/sys/Symbol.map +++ b/lib/libc/sys/Symbol.map @@ -211,6 +211,7 @@ FBSD_1.0 { pathconf; pipe; poll; + posix_openpt; preadv; profil; ptrace; diff --git a/lib/libc/sys/getrlimit.2 b/lib/libc/sys/getrlimit.2 index 93d91f6..d3550d2 100644 --- a/lib/libc/sys/getrlimit.2 +++ b/lib/libc/sys/getrlimit.2 @@ -28,7 +28,7 @@ .\" @(#)getrlimit.2 8.1 (Berkeley) 6/4/93 .\" $FreeBSD$ .\" -.Dd June 13, 2004 +.Dd August 20, 2008 .Dt GETRLIMIT 2 .Os .Sh NAME @@ -97,6 +97,8 @@ mbufs, that this user may hold at any time. The maximum size (in bytes) of the stack segment for a process; this defines how far a program's stack segment may be extended. Stack extension is performed automatically by the system. +.It Dv RLIMIT_NPTS +The maximum number of pseudo-terminals created by this user id. .El .Pp A resource limit is specified as a soft limit and a hard limit. diff --git a/lib/libc/sys/posix_openpt.2 b/lib/libc/sys/posix_openpt.2 new file mode 100644 index 0000000..2633847 --- /dev/null +++ b/lib/libc/sys/posix_openpt.2 @@ -0,0 +1,135 @@ +.\" Copyright (c) 2008 Ed Schouten +.\" All rights reserved. +.\" +.\" Portions of this software were developed under sponsorship from Snow +.\" B.V., the Netherlands. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" Portions of this text are reprinted and reproduced in electronic form +.\" from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- +.\" Portable Operating System Interface (POSIX), The Open Group Base +.\" Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of +.\" Electrical and Electronics Engineers, Inc and The Open Group. In the +.\" event of any discrepancy between this version and the original IEEE and +.\" The Open Group Standard, the original IEEE and The Open Group Standard is +.\" the referee document. The original Standard can be obtained online at +.\" http://www.opengroup.org/unix/online.html. +.\" +.\" $FreeBSD$ +.\" +.Dd August 20, 2008 +.Dt POSIX_OPENPT 2 +.Os +.Sh NAME +.Nm posix_openpt +.Nd "open a pseudo-terminal device" +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In stdlib.h +.In fcntl.h +.Ft int +.Fn posix_openpt "int oflag" +.Sh DESCRIPTION +The +.Fn posix_openpt +function allocates a new pseudo-terminal and establishes a connection +with its master device. +A slave device shall be created in +.Pa /dev/pts . +After the pseudo-terminal has been allocated, the slave device should +have the proper permissions before it can be used (see +.Xr grantpt 3 ) . +The name of the slave device can be determined by calling +.Xr ptsname 3 . +.Pp +The file status flags and file access modes of the open file description +shall be set according to the value of +.Fa oflag . +Values for +.Fa oflag +are constructed by a bitwise-inclusive OR of flags from the following +list, defined in +.In fcntl.h : +.Bl -tag -width ".Dv O_NOCTTY" +.It Dv O_RDWR +Open for reading and writing. +.It Dv O_NOCTTY +If set +.Fn posix_openpt +shall not cause the terminal device to become the controlling terminal +for the process. +.El +.Pp +The +.Fn posix_openpt +function shall fail when +.Fa oflag +contains other values. +.Sh RETURN VALUES +Upon successful completion, the +.Fn posix_openpt +function shall allocate a new pseudo-terminal device and return a +non-negative integer representing a file descriptor, which is connected +to its master device. +Otherwise, -1 shall be returned and errno set to indicate the error. +.Sh ERRORS +The +.Fn posix_openpt +function shall fail if: +.Bl -tag -width Er +.It Bq Er ENFILE +The system file table is full. +.It Bq Er EINVAL +The value of +.Fa oflag +is not valid. +.It Bq Er EAGAIN +Out of pseudo-terminal resources. +.El +.Sh SEE ALSO +.Xr pts 4 , +.Xr ptsname 3 , +.Xr tty 4 +.Sh STANDARDS +The +.Fn posix_openpt +function conforms to +.St -p1003.1-2001 . +.Sh HISTORY +The +.Fn posix_openpt +function appeared in +.Fx 5.0 . +In +.Fx 8.0 , +this function was changed to a system call. +.Sh NOTES +The flag +.Dv O_NOCTTY +is included for compatibility; in +.Fx , +opening a terminal does not cause it to become a process's controlling +terminal. +.Sh AUTHORS +.An Ed Schouten Aq ed@FreeBSD.org -- cgit v1.1