I demand that Deti Fliegl may or may not have written...
> Anssi Hannula wrote:
>> Deti Fliegl wrote:
>>> Klaus Schmidinger wrote:
>>>> Doesn't SystemExec() (see tools.c) take care of this?
>>> Yes you are right - it takes care internally but not for plugins like
>>> dvdswitch etc. In order to fix this problem you could patch every single
>>> plugin or just set the right file descriptor flag once. I think the
>>> latter does not cause any interference and should solves some issues.
>> For the record, the latter creates a small race condition: an external
>> program could be launched before FD_CLOEXEC is set on an fd.
> In VDR all file descriptors seem to be allocated at startup. IMHO it is
> not very likely that a race condition could happen.
>From open(2):
O_CLOEXEC (Since Linux 2.6.23)
Enable the close-on-exec flag for the new file descriptor.
Specifying this flag permits a program to avoid an additional
fcntl(2) F_SETFD operation to set the FD_CLOEXEC flag. Addi-
tionally, use of this flag is essential in some multithreaded
programs since using a separate fcntl(2) F_SETFD operation to
set the FD_CLOEXEC flag does not suffice to avoid race condi-
tions where one thread opens a file descriptor at the same time
as another thread does a fork(2) plus execve(2).
No use *now*, I know - too many people not yet using a new-enough kernel...
--
| Darren Salt | linux or ds at | nr. Ashington, | Toon
| RISC OS, Linux | youmustbejoking,demon,co,uk | Northumberland | Army
| Kill all extremists!
Vote Anarchist.
_______________________________________________
vdr mailing list
vdr@xxxxxxxxxxx
http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
