Re: [JunkMail] Fix for Bug 686946, ps2epsi segfaults

Jeong,

The logic looks good, but please get approval from Ray.

Igor.

----- Original Message ----- 
From: "Jeong Kim" <[email protected]>
To: "Gs-Code-Review" <[email protected]>
Sent: Sunday, August 10, 2003 6:04 PM
Subject: [JunkMail] [gs-code-review] Fix for Bug 686946, ps2epsi segfaults


> Reviewers,
> 
> Running ps2epsi with any file causes a SEGV error.
> When 'ps2epsi' procedure in ps2epsi.ps is executed
> an image device is made and is set by 'setdevice' operator.
> Then .setsafe is executed and thus setpagedevice is called.
> The SEGV occurs when 'setpagedevice' which is followed by 
> 'setdevice' and 'fillpage' is called.
> 
> Following is a simplified PostScript code for error reproduction.
> 
> matrix 1056 816 null
> makeimagedevice
> setdevice
> << >> setpagedevice
> 
> When 'setdevice' is called, a device is opened and 'setpagedevice'
> is called the opened device is closed. And any following attempts
> to draw something (e.g. fillpage) in the device would fail and 
> makes a SEGV.
> 
> Again, setpagedevice calls another setdevice and this calls
> 'gs_setdevice_no_init' and 'gs_closedevice' consequently.
> 
> In detail, 'gs_setdevice_no_init' calls 'gs_closedevice' to
> close an open device when the following condition is satisfied.
> 
>     if (pgs->device != NULL && pgs->device->rc.ref_count == 1) {
> 
> I think the reason why we close a device when gs_setdevice_no_init
> is called, is to close the current device when a new device is set.
> 
> So we must not close device when current device and new device 
> to set is same.
> 
> Following is the modified code to prevent closing current device
> which is same with new device.
> 
>     if (pgs->device != NULL && 
> pgs->device->rc.ref_count == 1 && 
> pgs->device != dev) {
> 
> With this simple patch, SEGV disppeared and ps2epsi works good.
> 
> Jeong
> 
> Log:
> gs_setdevice_no_init function sometimes closes a device
> when the current device and a new device to set is same.
> Now it doesn't. Bug 686946.
> 
> Index: src/gsdevice.c
> ===================================================================
> RCS file: /cvs/ghostscript/gs/src/gsdevice.c,v
> retrieving revision 1.19
> diff -C2 -r1.19 gsdevice.c
> *** src/gsdevice.c      25 Feb 2003 12:25:18 -0000      1.19
> --- src/gsdevice.c      10 Aug 2003 13:58:45 -0000
> ***************
> *** 402,406 ****
>        * device parameters.
>        */
> !     if (pgs->device != NULL && pgs->device->rc.ref_count == 1) {
>         int code = gs_closedevice(pgs->device);
> 
> --- 402,408 ----
>        * device parameters.
>        */
> !     if (pgs->device != NULL &&
> !       pgs->device->rc.ref_count == 1 &&
> !       pgs->device != dev) {
>         int code = gs_closedevice(pgs->device);
> 
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