On Tue, 07 Nov 2000, Sven Neumann <sven@xxxxxxxx> wrote: > quinet@xxxxxxxxxx (Raphael Quinet) writes: > > I think that the best way to fix the screenshot plug-in is to add this > > before the call to fork(): > > gimp_signal_private (SIGCHLD, SIG_DFL, SA_RESTART); > > (don't forget to #include <libgimp/gimpsignal.h>) > > This seems to work fine (at least under Linux). I'm only wondering why > the gz, bzip2 and mail plugins do work under Solaris then. Or is this > not the case ? Alas, these plug-ins have been broken under Solaris since a couple of months. I thought this was reported in the bug database, but apparently it isn't. That should have been a "grave" bug, at least. And the fix is exactly the same as for the screenshot plug-in: - make the code safer by checking the return value of waitpid, as described in my followup to #27786, - include <libgimp/gimpsignal.h>, - call gimp_signal_private (SIGCHLD, SIG_DFL, SA_RESTART) before calling fork(). A quick grep shows the list of plug-ins that call waitpid() in an unsafe way (do not check the result) and are affected by the race condition between the system call and the signal handler: - plug-ins/common/bz2.c (twice, for loading and saving) - plug-ins/common/gz.c (twice, for loading and saving) - plug-ins/common/mail.c - plug-ins/common/screenshot.c - plug-ins/common/url.c (twice, with ifdef/ifndef __EMX__) The print plug-in also calls waitpid, but it uses it only for its blocking effect and not for collecting the status of the child, so this plug-in is safe. It looks like all plug-ins authors copied and pasted the same code, because the same structure and the same argument names are used in all plug-ins. But this code was wrong: it was unsafe since the begining in 1.0.x, and broken when the new signal handlers were installed. It's a pity that the problem was not detected and fixed earlier (I am partly to blame for that, because I knew the problem and I did not check if it was reported in the bug database - I just told my users to avoid compressing files until the bugs were found and fixed). Anyway, I just fixed these five plug-ins and the patch should be in the incoming directory of ftp.gimp.org in a few minutes. Regarding bug #27786, I don't know if it is still open or not. I do not see any crashes under Solaris 2.6, but maybe Solaris 8 is still affected by the bug that was originally reported by Austin Donnelly. Could someone test this, as I don't have access to a Solaris 8 machine right now? -Raphael
