fbbd9655e5
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
90 lines
3.0 KiB
Groff
90 lines
3.0 KiB
Groff
.\" Copyright (c) 1985, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)sigreturn.2 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd September 6, 2013
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.Dt SIGRETURN 2
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.Os
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.Sh NAME
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.Nm sigreturn
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.Nd return from signal
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In signal.h
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.Ft int
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.Fn sigreturn "const ucontext_t *scp"
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.Sh DESCRIPTION
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The
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.Fn sigreturn
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system call
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allows users to atomically unmask, switch stacks,
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and return from a signal context.
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The thread's signal mask and stack status are
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restored from the context structure pointed to by
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.Fa scp .
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The system call does not return;
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the users stack pointer, frame pointer, argument pointer,
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and processor status longword are restored from the context.
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Execution resumes at the specified pc.
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This system call is used by the trampoline code and
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.Xr longjmp 3
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when returning from a signal to the previously executing program.
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.Sh RETURN VALUES
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If successful, the system call does not return.
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Otherwise, a value of -1 is returned and
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn sigreturn
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system call
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will fail and the thread context will remain unchanged
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if one of the following occurs.
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.Bl -tag -width Er
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.It Bq Er EFAULT
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The
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.Fa scp
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argument
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points to memory that is not a valid part of the process
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address space.
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.It Bq Er EINVAL
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The process status longword is invalid or would improperly
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raise the privilege level of the process.
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.El
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr setjmp 3 ,
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.Xr ucontext 3
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.Sh HISTORY
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The
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.Fn sigreturn
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system call appeared in
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.Bx 4.3 .
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