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Re: tcsh

To: ralf@uni-koblenz.de
Subject: Re: tcsh
From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Date: Sat, 4 Jul 1998 00:37:29 +0200
Cc: linux@cthulhu.engr.sgi.com
In-reply-to: <19980703165855.C435@uni-koblenz.de>; from ralf@uni-koblenz.de on Fri, Jul 03, 1998 at 04:58:55PM +0200
References: <19980622110139.F418@uni-koblenz.de> <19980703005927.48187@alpha.franken.de> <19980703165855.C435@uni-koblenz.de>
Sender: owner-linux@cthulhu.engr.sgi.com
On Fri, Jul 03, 1998 at 04:58:55PM +0200, ralf@uni-koblenz.de wrote:
> Sigpause() is a libc routine in libc/sysdeps/posix/sigpause.c; it's either
> using sigprocmask(2) or sigsuspend(2).

it's sigsuspend. And after looking at scall_o32.S and realizing that
calling do_signal() needs to have the static registers saved/restored,
the bug is obvious (I also had a look at the Alpha sys_sigsuspend). Below
is a patch, which fixes tcsh and other programs, which use sigsupend.
If everybody agrees with the patch, I'll check it in.

Thomas.

Index: scall_o32.S
===================================================================
RCS file: /var/mips/linus/cvs/linux/arch/mips/kernel/scall_o32.S,v
retrieving revision 1.3
diff -u -r1.3 scall_o32.S
--- scall_o32.S 1998/03/27 04:47:55     1.3
+++ scall_o32.S 1998/07/03 22:32:56
@@ -98,6 +98,18 @@
        jal     schedule
        b       o32_ret_from_sys_call
 
+EXPORT(sys_sigsuspend)
+       SAVE_STATIC
+       jal     do_sigsuspend
+       RESTORE_STATIC
+       b       o32_ret_from_sys_call
+
+EXPORT(sys_rt_sigsuspend)
+       SAVE_STATIC
+       jal     do_rt_sigsuspend
+       RESTORE_STATIC
+       b       o32_ret_from_sys_call
+
 /* ------------------------------------------------------------------------ */
 
 trace_a_syscall:
Index: signal.c
===================================================================
RCS file: /var/mips/linus/cvs/linux/arch/mips/kernel/signal.c,v
retrieving revision 1.12
diff -u -r1.12 signal.c
--- signal.c    1998/04/05 11:23:53     1.12
+++ signal.c    1998/07/03 22:31:58
@@ -38,8 +38,8 @@
 /*
  * Atomically swap in the new signal mask, and wait for a signal.
  */
-asmlinkage inline int
-sys_sigsuspend(struct pt_regs regs)
+int
+do_sigsuspend(struct pt_regs regs)
 {
        sigset_t *uset, saveset, newset;
 
@@ -62,8 +62,8 @@
        }
 }
 
-asmlinkage int
-sys_rt_sigsuspend(struct pt_regs regs)
+int
+do_rt_sigsuspend(struct pt_regs regs)
 {
        sigset_t *uset, saveset, newset;
 

-- 
See, you not only have to be a good coder to create a system like Linux,
you have to be a sneaky bastard too ;-)
                   [Linus Torvalds in <4rikft$7g5@linux.cs.Helsinki.FI>]

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