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Diffstat (limited to 'lib/libc/sys/sigaltstack.2')
| -rw-r--r-- | lib/libc/sys/sigaltstack.2 | 161 |
1 files changed, 0 insertions, 161 deletions
diff --git a/lib/libc/sys/sigaltstack.2 b/lib/libc/sys/sigaltstack.2 deleted file mode 100644 index eb29d2e588a6..000000000000 --- a/lib/libc/sys/sigaltstack.2 +++ /dev/null @@ -1,161 +0,0 @@ -.\" Copyright (c) 1983, 1991, 1992, 1993 -.\" The Regents of the University of California. All rights reserved. -.\" -.\" 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 University 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 REGENTS 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 REGENTS 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. -.\" -.\" @(#)sigaltstack.2 8.2 (Berkeley) 5/1/95 -.\" -.Dd May 6, 2010 -.Dt SIGALTSTACK 2 -.Os -.Sh NAME -.Nm sigaltstack -.Nd set and/or get signal stack context -.Sh LIBRARY -.Lb libc -.Sh SYNOPSIS -.In signal.h -.Bd -literal -typedef struct { - char *ss_sp; - size_t ss_size; - int ss_flags; -} stack_t; -.Ed -.Ft int -.Fn sigaltstack "const stack_t * restrict ss" "stack_t * restrict oss" -.Sh DESCRIPTION -The -.Fn sigaltstack -system call -allows defining an alternate stack on which signals -are to be processed for the current thread. -If -.Fa ss -is non-zero, -it specifies a pointer to and the size of a -.Em "signal stack" -on which to deliver signals. -When a signal's action indicates its handler -should execute on the signal stack (specified with a -.Xr sigaction 2 -system call), the system checks to see -if the thread is currently executing on that stack. -If the thread is not currently executing on the signal stack, -the system arranges a switch to the signal stack for the -duration of the signal handler's execution. -.Pp -An active stack cannot be modified. -.Pp -If -.Dv SS_DISABLE -is set in -.Fa ss_flags , -.Fa ss_sp -and -.Fa ss_size -are ignored and the signal stack will be disabled. -A disabled stack will cause all signals to be -taken on the regular user stack. -If the stack is later re-enabled then all signals that were specified -to be processed on an alternate stack will resume doing so. -.Pp -If -.Fa oss -is non-zero, the current signal stack state is returned. -The -.Fa ss_flags -field will contain the value -.Dv SS_ONSTACK -if the thread is currently on a signal stack and -.Dv SS_DISABLE -if the signal stack is currently disabled. -.Sh NOTES -The value -.Dv SIGSTKSZ -is defined to be the number of bytes/chars that would be used to cover -the usual case when allocating an alternate stack area. -The following code fragment is typically used to allocate an alternate stack. -.Bd -literal -offset indent -if ((sigstk.ss_sp = malloc(SIGSTKSZ)) == NULL) - /* error return */ -sigstk.ss_size = SIGSTKSZ; -sigstk.ss_flags = 0; -if (sigaltstack(&sigstk, NULL) < 0) - perror("sigaltstack"); -.Ed -An alternative approach is provided for programs with signal handlers -that require a specific amount of stack space other than the default size. -The value -.Dv MINSIGSTKSZ -is defined to be the number of bytes/chars that is required by -the operating system to implement the alternate stack feature. -In computing an alternate stack size, -programs should add -.Dv MINSIGSTKSZ -to their stack requirements to allow for the operating system overhead. -.Pp -Signal stacks are automatically adjusted for the direction of stack -growth and alignment requirements. -Signal stacks may or may not be protected by the hardware and -are not ``grown'' automatically as is done for the normal stack. -If the stack overflows and this space is not protected -unpredictable results may occur. -.Sh RETURN VALUES -.Rv -std sigaltstack -.Sh ERRORS -The -.Fn sigaltstack -system call -will fail and the signal stack context will remain unchanged -if one of the following occurs. -.Bl -tag -width Er -.It Bq Er EFAULT -Either -.Fa ss -or -.Fa oss -points to memory that is not a valid part of the process -address space. -.It Bq Er EPERM -An attempt was made to modify an active stack. -.It Bq Er EINVAL -The -.Fa ss_flags -field was invalid. -.It Bq Er ENOMEM -Size of alternate stack area is less than or equal to -.Dv MINSIGSTKSZ . -.El -.Sh SEE ALSO -.Xr sigaction 2 , -.Xr setjmp 3 -.Sh HISTORY -The predecessor to -.Fn sigaltstack , -the -.Fn sigstack -system call, appeared in -.Bx 4.2 . |