list on fork() if the process doesn't actually have references to any
semaphores. This avoids extra work, as well as potentially asking to
allocate storage for 0 references.
Found by: avatar
MFC after: 1 week
access to POSIX Semaphores:
mac_init_posix_sem() Initialize label for POSIX semaphore
mac_create_posix_sem() Create POSIX semaphore
mac_destroy_posix_sem() Destroy POSIX semaphore
mac_check_posix_sem_destroy() Check whether semaphore may be destroyed
mac_check_posix_sem_getvalue() Check whether semaphore may be queried
mac_check_possix_sem_open() Check whether semaphore may be opened
mac_check_posix_sem_post() Check whether semaphore may be posted to
mac_check_posix_sem_unlink() Check whether semaphore may be unlinked
mac_check_posix_sem_wait() Check whether may wait on semaphore
Update Biba, MLS, Stub, and Test policies to implement these entry points.
For information flow policies, most semaphore operations are effectively
read/write.
Submitted by: Dandekar Hrishikesh <rishi_dandekar at sbcglobal dot net>
Sponsored by: DARPA, McAfee, SPARTA
Obtained from: TrustedBSD Project
to ksem.h so that they are accessible from the MAC Framework for the
purposes of labeling and enforcing additional protections. #error
if these are included without _KERNEL, since they are not intended
(nor installed) for user application use.
Submitted by: Dandekar Hrishikesh <rishi_dandekar at sbcglobal dot net>
Sponsored by: DARPA, SPARTA
Obtained from: TrustedBSD Project
owned by a process when it forks, and creates a matching set of references
for the child process, as prescribed by POSIX.
In order to avoid races with other threads in the parent process during
fork(), it is necessary to allocate a temporary reference list while
holding the sem_lock, then transfer those references to the new process
once the sem_lock is released. The implementation is inefficient but
appears functional; in order to improve the efficiency, it will be
necessary to modify the existing structures and logic, which generally
rely on O(n) operations over the global set of semaphores.
Presumably, at some point, you had to include jail.h if you included
proc.h, but that is no longer required.
Result of: self injury involving adding something to struct prison
flexible process_fork, process_exec, and process_exit eventhandlers. This
reduces code duplication and also means that I don't have to go duplicate
the eventhandler locking three more times for each of at_fork, at_exec, and
at_exit.
Reviewed by: phk, jake, almost complete silence on arch@
that are shareable between processes.
There will be a cleanup shortly along with the necessary changes made to
libc, libc_r, libpthread as well as the hooks into sys/conf and sys/modules.
