2009/3/25 Girish <[email protected]> > > Hi, > > In cupcake (or any other branch) system V message queue wont be > supported what ? What is the reason for removing them ? Is there any > alternative for this ? >
Yes, all System V IPCs have been removed for cupcake. See bionic/libc/docs/SYSV-IPC.TXT for details. In brief, System V IPCs are leaky by design and do not play well in Android's runtime environment where killing processes to make room for other ones is just normal and very common. The end result is that any code that relies on these IPCs could end up filling up the kernel's internal table of SysV IPC keys, something that can only safely be resolved by a reboot. We want to provide alternative mechanism in the future that don't have the same problems. One thing we provide at the moment is ashmem, which was designed specifically for Android to avoid that kind of problem (though it's not as well documented as it should). We probably need something similar for semaphores and/or message queues. Note that PTHREAD_SHARED Posix mutexes don't have this problem, because they are cleaned up automatically when a process is killed by the kernel. However, we do not support them yet in our Pthread implementation. > > Regards > Girish > > > > On Mar 25, 6:57 am, Jean-Baptiste Queru <[email protected]> wrote: > > Very sorry, I have no visibility over that. > > > > JBQ > > > > 2009/3/24 muddog <[email protected]>: > > > > > > > > > > > > > On 3月21日, 上午10时25分, Jean-Baptiste Queru <[email protected]> wrote: > > >> From our internal revision control system: > > > > >> ---8<--- > > >> Remove support for System V IPCs in our C library. > > > > >> This is done to avoid potential nasty denial of service that may > > >> require rebooting the phone. For more details, see the new file > > >> named docs/SYSV-IPC.TXT > > >> ---8<--- > > > > > So, how about platform/external/alsa-lib? It use shmat(). > > > Need porting all SysV share memory calling to ashmem? > > > > >> JBQ > > > > >> 2009/3/20 Sean McNeil <[email protected]>: > > > > >> > In fact all of the routines are gone such as shmat(). How come? > > > > >> -- > > >> Jean-Baptiste M. "JBQ" Queru > > >> Android Engineer, Google. > > > > >> Questions sent directly to me that have no reason for being private > > >> will likely get ignored or forwarded to a public forum with no further > > >> warning. > > > > -- > > Jean-Baptiste M. "JBQ" Queru > > Android Engineer, Google. > > > > Questions sent directly to me that have no reason for being private > > will likely get ignored or forwarded to a public forum with no further > > warning. > > > --~--~---------~--~----~------------~-------~--~----~ unsubscribe: [email protected] website: http://groups.google.com/group/android-porting -~----------~----~----~----~------~----~------~--~---
