A mutex may be configured with rather exotic options such as recursive, unsafe, etc. The availability of these mutex options is controlled by configuation settings. When each option is enabled, additional fields are managed inside of the mutex structure.
pthread_cond_wait() and pthread_timed_wait() do the following atomically: (1) unlock the mutex, (2) wait for the condition, and (3) restore the mutex lock. When that lock is restored, pthread_cond_[timed]wait() must also restore the exact configuration of the mutex data structure if these "exotic" features are enabled.
Now that nxsem_wait_uninterruptible() returns an error when the thread is canceled, new logic is being executed. This revealed an existing error in pthread_cond_wait(). The nature of the error is as follows:
* pthread_cond_wait() must atomically (1) release the mutex, (2) wait on the condition, and (3) re-establish the mutex. Errors can occur on any of these steps. In this case the ECANCELED error was (very correctly) reported by nxsem_wait_uninterruptible().
* However, logic in step (3) had a bug; it re-acquired the mutex, but then a bug in existing logic cause the mutex to be improperly initialized. Essentially, the wrong error status value was being testing. This resulted in a nonsequitar and errors reported by the OS test.
This problem was found by apps/testing/ostest/pthread_cleanup.c
Resolution of Issue 619 will require multiple steps, this part of the first step in that resolution: Every call to nxsem_wait_uninterruptible() must handle the return value from nxsem_wait_uninterruptible properly. This commit is only for those files under graphics/, mm/, net/, sched/, wireless/bluetooth.
Still to do: Files under fs/, drivers/, and arch. The last is 116 files and will take some effort.
nxsem_timedwait_uninterruptible() must return -ECANCELED if the thread is canceled:
include/nuttx/semaphore.h: Return if nxsem_wait() returns ECANCELED meaning that the thread waiting for the semaphore has been canceled.
sched/semaphore/sem_timedwait.c: Same change (the inline version is in semaphore.h, the non-inlined version is in sem_tickwait.c).
drivers/sensors/lps25h.c and drivers/wireless/bluetooth/bt_uart_bcm4343x.c: Make sure that the caller deals correctly with the -ECANCELED return value.
Refer to issue 619.
* The appropriate size of stack varies among archs.
E.g. for 64-bit sim, 2048 is way too small, especially when the task
happens to use host OS functionalities.
I plan to allow an arch provide its own default.
* I plan to use this to replace hardcoded "STACKSIZE = 2048" in APPDIR.
Move the prototype for the internal OS from from sched/sched/sched.h to include/nuttx/sched.h. This was done because binfmt/binfmt/excecmodule.c requires the prototype for sched_releasetcb() and was illegally including sched/sched/sched.h. That is a blatant violation of the OS modular design and the person that did this should be hung up by their thumbs. Oh... I did that back in a bad moment in 2014. Now that is made right.
Update all files possible under sched/timer to Apache 2.0. These excludes two files that have a Xiaomi copyright. Also, run all modified files through nxstyle to assure that the conform to the coding standard.
PR #488 introduced an error in a file license header in file sched/mqueue/mqueue.h. This commit fixe that error and in the course of doing that, changing the license header to the standard Apache 2.0 header. I am the author and copyright hold of all modified files.
