[kde-freebsd] kde 4.3.4: preview thumbnails for pdf files

[Andriy Gapon]

Not sure if this is fixed in the new upcoming version, so decided to drop you a
line.  I use kde 4.3.4 on amd64 9-CURRENT machine and I observe some strange
problems with generation of preview/thumbnails for PDF files.
Specifically, I mean the previews that are shown in e.g. Dolphin when you hover
over a file name, both as tooltip-like popup and in information panel.
The problem is that generation of a preview seems to succeed or fail
semi-randomly.  I.e. sometimes I get a normal preview and sometimes only a mime
icon.
I dug a little bit into the issue and found the following:
  3453 100510 kdeinit4 CALL  wait4(0xd88,0x7fffffffcb3c,<invalid>0,0)
  3453 100510 kdeinit4 RET   wait4 -1 errno 4 Interrupted system call
  3453 100510 kdeinit4 PSIG  SIGCHLD caught handler=0x8007ce0b0 mask=0x0 code=0x0
...
  3453 100510 kdeinit4 GIO   fd 9 wrote 140 bytes
       "    82_66_\0\0\0h\0\0\0z\0C\0a\0n\0n\0o\0t\0 \0c\0r\0e\0a\0t\0e\0
\0t\0h\0u\0m\0b\0n\0a\0i\0l\0 \0f\0o\0r\0 \0/\0h\0o\0m\0e\0/\0a\0v\0g\0/\0d\0o\0c\0\
        /\0S\0p\0e\0c\0s\0/\0R\0o\0c\0k\0R\0i\0d\0g\0e\0.\0p\0d\0f"

The strange data seems to be a message "Cannot create thumbnail..." in unicode.
And the problem seems to be that thumbnail/preview code doesn't expect waitpid
to return with EINTR caused by SIGCHLD when a child (ghostscript process)
terminates.

This is a snippet from kdegraphics-4.3.4/thumbnailers/ps/gscreator.cpp:
if (waitpid(pid, &status, 0) != pid || (status != 0  && status != 256) )
  ok = false;

I believe that EINTR might be generated here, because some wrapping KDE-generic
code installs a SIGCHLD handler.  But I am not sure about that.
I am also not sure if FreeBSD behaves correctly here in either case.

-- 
Andriy Gapon