Date: Sat, 16 Feb 2002 10:42:15 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Peter Wemm <peter@wemm.org> Cc: Dan Eischen <eischen@vigrid.com>, arch@FreeBSD.ORG Subject: MFC makecontext(), getcontext(), setcontext()?, also would be nice to have some cleanups Message-ID: <200202161842.g1GIgFF89658@apollo.backplane.com> References: <20020206195918.6350039F1@overcee.wemm.org>
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It would be nice if getcontext() and setcontext() could be told
not to screw around with the signal mask, similar to what sigsetjmp()
and siglongjmp() do if the savemask is empty. Perhaps something like
this:
BEFORE:
2: PIC_PROLOGUE
pushl $0 /* oset = NULL */
pushl %eax /* set = &ucp->uc_sigmask */
pushl $3 /* how = SIG_SETMASK */
call PIC_PLT(CNAME(_sigprocmask))
addl $12, %esp
PIC_EPILOGUE
AFTER:
2: PIC_PROLOGUE
testl (%eax) <<<<<<<<<<< ADD
jz 21f <<<<<<<<<<< ADD
pushl $0 /* oset = NULL */
pushl %eax /* set = &ucp->uc_sigmask */
pushl $3 /* how = SIG_SETMASK */
call PIC_PLT(CNAME(_sigprocmask))
addl $12, %esp
PIC_EPILOGUE
testl %eax,%eax
jnz 5f
21: <<<<<<<<<<< ADD
(make same change in both setcontext() and getcontext())
This way these calls could be used to replace the alternate signal
stack, sigsetjmp()/setlongjmp() junk that has to be done now in
roll-your-own threads systems.
Any objections to me doing this?
I would also like to MFC these functions to -stable at some point.
-Matt
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