[src/trunk]: src/sys/compat/linux/arch/i386 execute signal handlers on separa...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f576b3eca3ee
branches:  trunk
changeset: 512742:f576b3eca3ee
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sun Jul 15 20:02:21 2001 +0000

description:
execute signal handlers on separate signal stack, if it's been provided

diffstat:

 sys/compat/linux/arch/i386/linux_machdep.c |  32 ++++++++++++++++++++++++-----
 1 files changed, 26 insertions(+), 6 deletions(-)

diffs (78 lines):

diff -r 3aa6b7af31e1 -r f576b3eca3ee sys/compat/linux/arch/i386/linux_machdep.c
--- a/sys/compat/linux/arch/i386/linux_machdep.c        Sun Jul 15 17:31:02 2001 +0000
+++ b/sys/compat/linux/arch/i386/linux_machdep.c        Sun Jul 15 20:02:21 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_machdep.c,v 1.65 2001/06/17 21:01:38 sommerfeld Exp $    */
+/*     $NetBSD: linux_machdep.c,v 1.66 2001/07/15 20:02:21 jdolecek Exp $      */
 
 /*-
  * Copyright (c) 1995, 2000 The NetBSD Foundation, Inc.
@@ -150,12 +150,21 @@
        struct proc *p = curproc;
        struct trapframe *tf;
        struct linux_sigframe *fp, frame;
+       int onstack;
 
        tf = p->p_md.md_regs;
 
+       /* Do we need to jump onto the signal stack? */
+       onstack =
+           (p->p_sigctx.ps_sigstk.ss_flags & (SS_DISABLE | SS_ONSTACK)) == 0 &&
+           (SIGACTION(p, sig).sa_flags & SA_ONSTACK) != 0;
+
        /* Allocate space for the signal handler context. */
-       /* XXX Linux doesn't support the signal stack. */
-       fp = (struct linux_sigframe *)tf->tf_esp;
+       if (onstack)
+               fp = (struct linux_sigframe *)((caddr_t)p->p_sigctx.ps_sigstk.ss_sp +
+                                         p->p_sigctx.ps_sigstk.ss_size);
+       else
+               fp = (struct linux_sigframe *)tf->tf_esp;
        fp--;
 
        /* Build stack frame for signal trampoline. */
@@ -194,7 +203,7 @@
        frame.sf_sc.sc_trapno = tf->tf_trapno;
 
        /* Save signal stack. */
-       /* XXX Linux doesn't support the signal stack. */
+       /* Linux doesn't save the onstack flag in sigframe */
 
        /* Save signal mask. */
        native_to_linux_old_sigset(mask, &frame.sf_sc.sc_mask);
@@ -220,7 +229,8 @@
        tf->tf_ss = GSEL(GUDATA_SEL, SEL_UPL);
 
        /* Remember that we're now on the signal stack. */
-       /* XXX Linux doesn't support the signal stack. */
+       if (onstack)
+               p->p_sigctx.ps_sigstk.ss_flags |= SS_ONSTACK;
 }
 
 /*
@@ -255,6 +265,7 @@
        struct linux_sigcontext *scp, context;
        struct trapframe *tf;
        sigset_t mask;
+       ssize_t ss_gap;
 
        /*
         * The trampoline code hands us the context.
@@ -305,7 +316,16 @@
        tf->tf_ss = context.sc_ss;
 
        /* Restore signal stack. */
-       p->p_sigctx.ps_sigstk.ss_flags &= ~SS_ONSTACK;
+       /*
+        * Linux really does it this way; it doesn't have space in sigframe
+        * to save the onstack flag.
+        */
+       ss_gap = (ssize_t)
+           ((caddr_t) context.sc_esp_at_signal - (caddr_t) p->p_sigctx.ps_sigstk.ss_sp);
+       if (ss_gap >= 0  && ss_gap < p->p_sigctx.ps_sigstk.ss_size)
+               p->p_sigctx.ps_sigstk.ss_flags |= SS_ONSTACK;
+       else
+               p->p_sigctx.ps_sigstk.ss_flags &= ~SS_ONSTACK;
 
        /* Restore signal mask. */
        linux_old_to_native_sigset(&context.sc_mask, &mask);