On Friday 11 July 2003 22:47, Andrey Borzenkov wrote:
> I cannot believe it is so fragile ...
>
> is_devfsd_or_child() simplemindedly checks for pgrp:
>
> static int is_devfsd_or_child (struct fs_info *fs_info)
> {
> if (current == fs_info->devfsd_task) return (TRUE);
> if (current->pgrp == fs_info->devfsd_pgrp) return (TRUE);
> return (FALSE);
> } /* End Function is_devfsd_or_child */
>
Andrew, one more for your collection :)
The code that did proper check existed in 2.4 and was removed in 2.5 for
whatever reason. The patch restores it slightly modified as below.
2.4 code looks somewhat unclean in that
- it traverses task list without lock.
- is starts from current->real_parent but nothing prevents current be
init_task itself. This hung for me on 2.5 during boot. May be 2.4 does
something differently.
Comments?
regards
-andrey
This is trivially reproduced under 2.5 by using devfsd.conf lines
LOOKUP ^foo$ EXECUTE /home/bor/tmp/devfsd/handler /dev/bar
LOOKUP ^bar$ EXECUTE /home/bor/tmp/devfsd/handler /dev/foo
and handler like
-------- cut here ----------
#include <unistd.h>
int
main(int argc, char **argv, char **envp)
{
if (argc <= 1)
return 0;
setpgrp();
return access(argv[1], R_OK);
}
-------- cut here ----------
and doing ls /dev/foo
-
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This archive was generated by hypermail 2b29 : Tue Jul 15 2003 - 22:00:43 EST