101 lines
3.5 KiB
Groff
101 lines
3.5 KiB
Groff
.\" Copyright (c) 1983, 1991 The Regents of the University of California.
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.\" 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. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. 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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.\" @(#)sigstack.2 6.5 (Berkeley) 3/10/91
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.\"
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.Dd March 10, 1991
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.Dt SIGSTACK 2
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.Os BSD 4.2
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.Sh NAME
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.Nm sigstack
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.Nd set and/or get signal stack context
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.Sh SYNOPSIS
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.Fd #include <sys/signal.h>
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.Bd -literal
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struct sigstack {
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caddr_t ss_sp;
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int ss_onstack;
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};
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.Ed
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.Ft int
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.Fn sigstack "const struct sigstack *ss" "struct sigstack *oss"
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.Sh DESCRIPTION
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.Fn Sigstack
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allows users to define an alternate stack on which signals
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are to be processed. If
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.Fa ss
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is non-zero,
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it specifies a
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.Em "signal stack"
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on which to deliver signals
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and tells the system if the process is currently executing
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on that stack. When a signal's action indicates its handler
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should execute on the signal stack (specified with a
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.Xr sigvec 2
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call), the system checks to see
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if the process is currently executing on that stack. If the
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process is not currently executing on the signal stack,
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the system arranges a switch to the signal stack for the
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duration of the signal handler's execution.
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If
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.Fa oss
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is non-zero, the current signal stack state is returned.
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.Sh NOTES
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Signal stacks are not ``grown'' automatically, as is
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done for the normal stack. If the stack overflows
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unpredictable results may occur.
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.Sh RETURN VALUES
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Upon successful completion, a value of 0 is returned.
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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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.Fn Sigstack
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will fail and the signal stack context will remain unchanged
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if one of the following occurs.
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.Bl -tag -width [EFAULT]
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.It Bq Er EFAULT
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Either
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.Fa ss
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or
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.Fa oss
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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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.El
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.Sh SEE ALSO
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.Xr sigvec 2 ,
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.Xr setjmp 3
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.Sh HISTORY
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The
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.Nm
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function call appeared in
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.Bx 4.2 .
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