Attachment 16120 Details for Bug 10212 – 0001-dix-set-up-siglongjmp-to-jump-to-in-case-of-a-Fatal.patch

[patch] 0001-dix-set-up-siglongjmp-to-jump-to-in-case-of-a-Fatal.patch

0001-dix-set-up-siglongjmp-to-jump-to-in-case-of-a-Fatal.patch (text/plain), 3.08 KB, created by Peter Hutterer on 2008-04-22 23:44:01 UTC

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Creator: Peter Hutterer

Created: 2008-04-22 23:44:01 UTC

Size: 3.08 KB

patch

obsolete

>From 8718ed739d79d4792362172fee3c6bcdea8c5721 Mon Sep 17 00:00:00 2001
>From: Peter Hutterer <peter@cs.unisa.edu.au>
>Date: Wed, 23 Apr 2008 16:04:08 +0930
>Subject: [PATCH] dix: set up siglongjmp to jump to in case of a FatalError.
>
>Calling FatalError from within xf86SignalHandler is not POSIX compliant (it
>calls free() on the way out). So we set up a siglongjmp environment at the
>start of main() and jump back here before we bring the server down.
>---
> dix/main.c                     |   16 ++++++++++++++++
> hw/xfree86/common/xf86Events.c |    9 ++++++++-
> include/dix.h                  |    4 ++++
> 3 files changed, 28 insertions(+), 1 deletions(-)
>
>diff --git a/dix/main.c b/dix/main.c
>index f7824ee..cc17416 100644
>--- a/dix/main.c
>+++ b/dix/main.c
>@@ -119,6 +119,12 @@ Equipment Corporation.
> #include "dpmsproc.h"
> #endif
> 
>+/**
>+ * siglongjmp environment set up in Dispatch(). Used by xf86SignalHandler to
>+ * jump out when a FatalError is needed.
>+ */
>+sigjmp_buf sigjmp_env;
>+
> extern void Dispatch(void);
> 
> char *ConnectionInfo;
>@@ -247,9 +253,19 @@ main(int argc, char *argv[], char *envp[])
>     int		i, j, k, error;
>     char	*xauthfile;
>     HWEventQueueType	alwaysCheckForInput[2];
>+    int sig;
> 
>     display = "0";
> 
>+
>+    /* Set up a signal longjump. If a SEGV or other signal will bring the
>+     * server down, we jump here to be able to FatalError().
>+     */
>+    if ((sig = sigsetjmp(sigjmp_env, 0)))
>+    {
>+        FatalError("Aborting after receiving signal %d.\n", sig);
>+    }
>+
>     InitGlobals();
>     InitRegions();
> #ifdef XPRINT
>diff --git a/hw/xfree86/common/xf86Events.c b/hw/xfree86/common/xf86Events.c
>index d1e4393..a07f066 100644
>--- a/hw/xfree86/common/xf86Events.c
>+++ b/hw/xfree86/common/xf86Events.c
>@@ -125,6 +125,7 @@ _X_EXPORT Bool VTSwitchEnabled = TRUE;	/* Allows run-time disabling for
>                                          *BSD and for avoiding VT
>                                          switches when using the DRI
>                                          automatic full screen mode.*/
>+extern sigjmp_buf sigjmp_env;
> 
> extern fd_set EnabledDevices;
> 
>@@ -764,8 +765,14 @@ xf86SigHandler(int signo)
> #endif
> 
>   xorg_backtrace();
>+  ErrorF("Caught signal %d. Server aborting.\n", signo);
> 
>-  FatalError("Caught signal %d.  Server aborting\n", signo);
>+  /* Do not call FatalError() here. It will close down the devices and thus
>+   * call free(), which is a no-no from within a signal handler.
>+   * We have to siglongjmp out of here before we bring the server down.
>+   * The sig longjmp environment was set up first thin in main().
>+   */
>+  siglongjmp(sigjmp_env, signo);
> }
> 
> static void
>diff --git a/include/dix.h b/include/dix.h
>index 57ffee9..014c8f6 100644
>--- a/include/dix.h
>+++ b/include/dix.h
>@@ -47,6 +47,7 @@ SOFTWARE.
> 
> #ifndef DIX_H
> #define DIX_H
>+#include <setjmp.h>
> 
> #include "gc.h"
> #include "window.h"
>@@ -305,6 +306,9 @@ extern void InitAtoms(void);
> 
> /* main.c */
> 
>+/* Environment for siglongjmp. Will be set up in main(). */
>+extern sigjmp_buf sigjmp_env;
>+
> extern void SetVendorRelease(int release);
> 
> extern void SetVendorString(char *string);
>-- 
>1.5.3
>

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