Update sigaction syscall names to act more like glibc. Fix the x86 sigaction

implementation such that gdb can actually debug signal handlers.  Gdb behaves
much better now, for example, on multi-threaded apps.
 -Erik

2 files changed, 170 insertions, 1 deletions

diff --git a/libc/sysdeps/linux/i386/Makefile b/libc/sysdeps/linux/i386/Makefile
index 77c8c815d..dbbe7db11 100644
--- a/libc/sysdeps/linux/i386/Makefile
+++ b/libc/sysdeps/linux/i386/Makefile
@@ -32,7 +32,7 @@ SSRC=__longjmp.S vfork.S clone.S setjmp.S bsd-setjmp.S \
 	bsd-_setjmp.S syscall.S
 SOBJS=$(patsubst %.S,%.o, $(SSRC))
 
-CSRC=brk.c
+CSRC=brk.c sigaction.c
 COBJS=$(patsubst %.c,%.o, $(CSRC))
 
 OBJS=$(SOBJS) $(COBJS)
diff --git a/libc/sysdeps/linux/i386/sigaction.c b/libc/sysdeps/linux/i386/sigaction.c
new file mode 100644
index 000000000..c05950793
--- /dev/null
+++ b/libc/sysdeps/linux/i386/sigaction.c
@@ -0,0 +1,169 @@
+/* Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  
+
+   Totally hacked up for uClibc by Erik Andersen <andersen@codepoet.org>
+   */
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <bits/kernel_sigaction.h>
+
+#define SA_RESTORER	0x04000000
+
+
+#if defined __NR_rt_sigaction
+#warning "Yes there are two warnings here.  Don't worry about it."
+static void restore_rt (void) asm ("__restore_rt");
+static void restore (void) asm ("__restore");
+
+/* If ACT is not NULL, change the action for SIG to *ACT.
+   If OACT is not NULL, put the old action for SIG in *OACT.  */
+int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
+{
+    int result;
+    struct kernel_sigaction kact, koact;
+
+#ifdef SIGCANCEL
+    if (sig == SIGCANCEL) {
+	__set_errno (EINVAL);
+	return -1;
+    }
+#endif
+
+    if (act) {
+	kact.k_sa_handler = act->sa_handler;
+	memcpy (&kact.sa_mask, &act->sa_mask, sizeof (kact.sa_mask));
+	kact.sa_flags = act->sa_flags;
+
+	kact.sa_flags = act->sa_flags | SA_RESTORER;
+	kact.sa_restorer = ((act->sa_flags & SA_SIGINFO)
+		? &restore_rt : &restore);
+    }
+
+    /* XXX The size argument hopefully will have to be changed to the
+       real size of the user-level sigset_t.  */
+    result = __syscall_rt_sigaction(sig, act ? __ptrvalue (&kact) : NULL,
+	    oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
+
+    if (oact && result >= 0) {
+	oact->sa_handler = koact.k_sa_handler;
+	memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (oact->sa_mask));
+	oact->sa_flags = koact.sa_flags;
+	oact->sa_restorer = koact.sa_restorer;
+    }
+    return result;
+}
+
+
+#else
+#warning "Yes there is a warning here.  Don't worry about it."
+static void restore (void) asm ("__restore");
+
+/* If ACT is not NULL, change the action for SIG to *ACT.
+   If OACT is not NULL, put the old action for SIG in *OACT.  */
+int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
+{
+    int result;
+    struct old_kernel_sigaction kact, koact;
+
+#ifdef SIGCANCEL
+    if (sig == SIGCANCEL) {
+	__set_errno (EINVAL);
+	return -1;
+    }
+#endif
+
+    if (act) {
+	kact.k_sa_handler = act->sa_handler;
+	kact.sa_mask = act->sa_mask.__val[0];
+	kact.sa_flags = act->sa_flags | SA_RESTORER;
+	kact.sa_restorer = &restore;
+    }
+    result = __syscall_sigaction(sig, act ? __ptrvalue (&kact) : NULL,
+	    oact ? __ptrvalue (&koact) : NULL);
+
+    asm volatile ("pushl %%ebx\n"
+	    "movl %2, %%ebx\n"
+	    "int $0x80\n"
+	    "popl %%ebx"
+	    : "=a" (result)
+	    : "0" (SYS_ify (sigaction)), "mr" (sig),
+	    "c" (act ? __ptrvalue (&kact) : 0),
+	    "d" (oact ? __ptrvalue (&koact) : 0));
+
+    if (result < 0) {
+	__set_errno(-result);
+	return -1;
+    }
+
+    if (oact) {
+	oact->sa_handler = koact.k_sa_handler;
+	oact->sa_mask.__val[0] = koact.sa_mask;
+	oact->sa_flags = koact.sa_flags;
+	oact->sa_restorer = koact.sa_restorer;
+    }
+    return result;
+}
+
+#endif
+weak_alias (__libc_sigaction, sigaction)
+
+
+
+
+/* NOTE: Please think twice before making any changes to the bits of
+   code below.  GDB needs some intimate knowledge about it to
+   recognize them as signal trampolines, and make backtraces through
+   signal handlers work right.  Important are both the names
+   (__restore and __restore_rt) and the exact instruction sequence.
+   If you ever feel the need to make any changes, please notify the
+   appropriate GDB maintainer.  */
+
+#define RESTORE(name, syscall) RESTORE2 (name, syscall)
+#define RESTORE2(name, syscall) \
+asm						\
+  (						\
+   ".text\n"					\
+   "	.align 16\n"				\
+   "__" #name ":\n"				\
+   "	movl $" #syscall ", %eax\n"		\
+   "	int  $0x80"				\
+   );
+
+#ifdef __NR_rt_sigaction
+/* The return code for realtime-signals.  */
+RESTORE (restore_rt, __NR_rt_sigreturn)
+#endif
+
+/* For the boring old signals.  */
+# undef RESTORE2
+# define RESTORE2(name, syscall) \
+asm						\
+  (						\
+   ".text\n"					\
+   "	.align 8\n"				\
+   "__" #name ":\n"				\
+   "	popl %eax\n"				\
+   "	movl $" #syscall ", %eax\n"		\
+   "	int  $0x80"				\
+   );
+
+RESTORE (restore, __NR_sigreturn)
+