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Add man pages for getcontext()/setcontext(), makecontext()/swapcontext(),

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and ucontext_t.

Reviewed by:	mini
MFC after:	3 days
This commit is contained in:
Archie Cobbs 2002-09-11 21:39:21 +00:00
parent 877b0861ca
commit a892767bc4
4 changed files with 331 additions and 5 deletions
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12
lib/libc/gen/Makefile.inc
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@ -42,22 +42,22 @@ MAN+= alarm.3 arc4random.3 \
confstr.3 ctermid.3 daemon.3 \
devname.3 directory.3 dirname.3 dladdr.3 dllockinit.3 dlopen.3 \
err.3 exec.3 fmtcheck.3 fmtmsg.3 fnmatch.3 frexp.3 ftok.3 fts.3 \
getbootfile.3 getbsize.3 getcap.3 getcwd.3 \
getbootfile.3 getbsize.3 getcap.3 getcontext.3 getcwd.3 \
getdiskbyname.3 getdomainname.3 getfsent.3 \
getgrent.3 getgrouplist.3 gethostname.3 getloadavg.3 \
getmntinfo.3 getnetgrent.3 getobjformat.3 \
getpagesize.3 getpass.3 getpeereid.3 getprogname.3 getpwent.3 \
getttyent.3 getusershell.3 getvfsbyname.3 getvfsent.3 \
glob.3 initgroups.3 isinf.3 \
ldexp.3 lockf.3 modf.3 msgctl.3 msgget.3 msgrcv.3 msgsnd.3 \
glob.3 initgroups.3 isinf.3 ldexp.3 lockf.3 makecontext.3 \
modf.3 msgctl.3 msgget.3 msgrcv.3 msgsnd.3 \
nice.3 nlist.3 pause.3 popen.3 pselect.3 psignal.3 pwcache.3 \
raise.3 rand48.3 readpassphrase.3 rfork_thread.3 \
scandir.3 setjmp.3 setmode.3 setproctitle.3 shm_open.3 \
siginterrupt.3 signal.3 sigsetops.3 sleep.3 statvfs.3 stringlist.3 \
strtofflags.3 sysconf.3 sysctl.3 syslog.3 tcgetpgrp.3 \
tcsendbreak.3 tcsetattr.3 tcsetpgrp.3 time.3 times.3 timezone.3 \
ttyname.3 tzset.3 ualarm.3 ulimit.3 uname.3 unvis.3 usleep.3 utime.3 \
valloc.3 vis.3
ttyname.3 tzset.3 ualarm.3 ucontext.3 ulimit.3 uname.3 \
unvis.3 usleep.3 utime.3 valloc.3 vis.3
MLINKS+=arc4random.3 arc4random_addrandom.3 arc4random.3 arc4random_stir.3
MLINKS+=ctermid.3 ctermid_r.3
@ -78,6 +78,7 @@ MLINKS+=getcap.3 cgetcap.3 getcap.3 cgetclose.3 getcap.3 cgetent.3 \
getcap.3 cgetnum.3 getcap.3 cgetset.3 getcap.3 cgetstr.3 \
getcap.3 cgetustr.3
MLINKS+=getcwd.3 getwd.3
MLINKS+=getcontext.3 setcontext.3
MLINKS+=getdomainname.3 setdomainname.3
MLINKS+=getfsent.3 endfsent.3 getfsent.3 getfsfile.3 getfsent.3 getfsspec.3 \
getfsent.3 getfstype.3 getfsent.3 setfsent.3
@ -98,6 +99,7 @@ MLINKS+=getvfsent.3 endvfsent.3 getvfsent.3 getvfsbytype.3 \
getvfsent.3 vfsload.3
MLINKS+=glob.3 globfree.3
MLINKS+=isinf.3 isnan.3 isinf.3 isnanf.3
MLINKS+=makecontext.3 swapcontext.3
MLINKS+=popen.3 pclose.3
MLINKS+=psignal.3 strsignal.3 psignal.3 sys_siglist.3 psignal.3 sys_signame.3
MLINKS+=pwcache.3 group_from_gid.3 pwcache.3 user_from_uid.3

119
lib/libc/gen/getcontext.3 Normal file
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@ -0,0 +1,119 @@
.\" Copyright (c) 2002 Packet Design, LLC.
.\" All rights reserved.
.\"
.\" Subject to the following obligations and disclaimer of warranty,
.\" use and redistribution of this software, in source or object code
.\" forms, with or without modifications are expressly permitted by
.\" Packet Design; provided, however, that:
.\"
.\" (i) Any and all reproductions of the source or object code
.\" must include the copyright notice above and the following
.\" disclaimer of warranties; and
.\" (ii) No rights are granted, in any manner or form, to use
.\" Packet Design trademarks, including the mark "PACKET DESIGN"
.\" on advertising, endorsements, or otherwise except as such
.\" appears in the above copyright notice or in the software.
.\"
.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
.\" OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
.\" RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 PACKET DESIGN IS ADVISED OF
.\" THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd Sep 10, 2002
.Dt GETCONTEXT 3
.Os
.Sh NAME
.Nm getcontext
.Nm setcontext
.Nd get and set user thread context
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ucontext.h
.Ft int
.Fn getcontext "ucontext_t *ucp"
.Ft int
.Fn setcontext "const ucontext_t *ucp"
.Sh DESCRIPTION
.Fn getcontext
saves the current thread's execution context in the structure pointed to by
.Fa "ucp" .
This saved context may then later be restored by calling
.Fn setcontext .
.Pp
.Fn setcontext
makes a previously saved thread context the current thread context, i.e.,
the current context is lost and
.Fn setcontext
does not return.
Instead, execution continues in the context specified by
.Fa "ucp" ,
which must have been previously initialized by a call to
.Fn setcontext ,
.Fn makecontext ,
or by being passed as an argument to a signal handler (see
.Xr sigaction 2) .
.Pp
If
.Fa ucp
was initialized by
.Fn getcontext ,
then execution continues as if the original
.Fn getcontext
call had just returned (again).
.Pp
If
.Fa ucp
was initialized by
.Fn makecontext ,
execution continues with the invocation of the function specified to
.Fn makecontext .
When that function returns,
.Fa "ucp->uc_link"
determines what happens next:
if
.Fa "ucp->uc_link"
is
.Dv NULL ,
the process exits;
otherwise,
.Fn setcontext "ucp->uc_link"
is implicitly invoked.
.Pp
If
.Fa ucp
was initialized by the invocation of a signal handler, execution continues
at the point the thread was interrupted by the signal.
.Ed
.Sh RETURN VALUES
If successful,
.Fn getcontext
returns zero and
.Fn setcontext
does not return; otherwise -1 is returned.
.Sh ERRORS
No errors are defined for
.Fn getcontext
or
.Fn setcontext .
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr sigaltstack 2 ,
.Xr makecontext 3 ,
.Xr ucontext 3

107
lib/libc/gen/makecontext.3 Normal file
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@ -0,0 +1,107 @@
.\" Copyright (c) 2002 Packet Design, LLC.
.\" All rights reserved.
.\"
.\" Subject to the following obligations and disclaimer of warranty,
.\" use and redistribution of this software, in source or object code
.\" forms, with or without modifications are expressly permitted by
.\" Packet Design; provided, however, that:
.\"
.\" (i) Any and all reproductions of the source or object code
.\" must include the copyright notice above and the following
.\" disclaimer of warranties; and
.\" (ii) No rights are granted, in any manner or form, to use
.\" Packet Design trademarks, including the mark "PACKET DESIGN"
.\" on advertising, endorsements, or otherwise except as such
.\" appears in the above copyright notice or in the software.
.\"
.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
.\" OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
.\" RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 PACKET DESIGN IS ADVISED OF
.\" THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd Sep 10, 2002
.Dt MAKECONTEXT 3
.Os
.Sh NAME
.Nm makecontext
.Nm swapcontext
.Nd modify and exchange user thread contexts
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ucontext.h
.Ft void
.Fn makecontext "ucontext_t *ucp" "void (*func)()" "int argc" "..."
.Ft int
.Fn swapcontext "ucontext_t *oucp" "const ucontext_t *ucp"
.Sh DESCRIPTION
.Fn makecontext
modifies the user thread context pointed to by
.Fa ucp ,
which must have previously been initialized by a call to
.Fn getcontext
and had a stack allocated for it.
The context is modified so that it will continue execution by invoking
.Fn func
with the arguments provided.
.Fa argc
must be equal to the number of additional arguments provided to
.Fn makecontext
and also equal to the number of parameters to
.Fn func ,
or else the behavior is undefined.
.Pp
.Fa "ucp->uc_link"
must be initialized before calling
.Fn makecontext
and determines the action to take when
.Fn func
returns:
if equal to
.Dv NULL ,
the process exits;
otherwise,
.Fn setcontext "ucp->uc_link"
is implicitly invoked.
.Pp
.Fn swapcontext
saves the current thread context in
.Fa "*oucp"
and makes
.Fa "*ucp"
the currently active context.
.Sh RETURN VALUES
If successful,
.Fn swapcontext
returns zero;
otherwise -1 is returned and
.Va errno
is set appropriately.
.Sh ERRORS
.Fn swapcontext
will fail if:
.Bl -tag -width Er
.It Bq Er ENOMEM
There is not enough stack space in
.Fa ucp
to complete the operation.
.El
.Sh SEE ALSO
.Xr setcontext 3 ,
.Xr ucontext 3

98
lib/libc/gen/ucontext.3 Normal file
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@ -0,0 +1,98 @@
.\" Copyright (c) 2002 Packet Design, LLC.
.\" All rights reserved.
.\"
.\" Subject to the following obligations and disclaimer of warranty,
.\" use and redistribution of this software, in source or object code
.\" forms, with or without modifications are expressly permitted by
.\" Packet Design; provided, however, that:
.\"
.\" (i) Any and all reproductions of the source or object code
.\" must include the copyright notice above and the following
.\" disclaimer of warranties; and
.\" (ii) No rights are granted, in any manner or form, to use
.\" Packet Design trademarks, including the mark "PACKET DESIGN"
.\" on advertising, endorsements, or otherwise except as such
.\" appears in the above copyright notice or in the software.
.\"
.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
.\" OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
.\" RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 PACKET DESIGN IS ADVISED OF
.\" THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd Sep 10, 2002
.Dt UCONTEXT 3
.Os
.Sh NAME
.Nm ucontext
.Nd user thread context
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ucontext.h
.Sh DESCRIPTION
The
.Vt ucontext_t
type is a structure type suitable for holding the context for a user
thread of execution.
A thread's context includes its stack, saved registers, and list of
blocked signals.
.Pp
The
.Vt ucontext_t
structure contains at least these fields:
.Bl -tag -compact -offset 3n -width "mcontext_t uc_mcontext"
.Pp
.It "ucontext_t *uc_link"
Context to assume when this one returns
.It "sigset_t uc_sigmask"
Signals being blocked
.It "stack_t uc_stack"
Stack area
.It "mcontext_t uc_mcontext"
Saved registers
.El
.Pp
The
.Fa uc_link
field points to the context to resume when this context's entry point
function returns.
If
.Fa uc_link
is equal to
.Dv NULL ,
then the process exits when this context returns.
.Pp
The
.Fa uc_mcontext
field is machine-dependent and should be treated as opaque by
portable applications.
.Pp
The following functions are defined to manipulate
.Vt ucontext_t
structures:
.Bd -literal -offset xxx
int getcontext(ucontext_t *);
int setcontext(const ucontext_t *);
void makecontext(ucontext_t *, void (*)(void), int, ...);
int swapcontext(ucontext_t *, const ucontext_t *);
.Ed
.Sh SEE ALSO
.Xr sigaltstack 2 ,
.Xr getcontext 3 ,
.Xr makecontext 3