This PR corrects an error in the ROMFS file system. The error occurred after following a hard link (depending on how the ROMFS image is organized). The error occurred because some of the information buffered before following the links was stale and, hence, out of sync after following the hard link. This would cause random errors when paths containing hardlinks were used with ROMFS.
This PR resolves Issue #1543. Please compare the following output with the output in Issue #1543 to see how the problem was resolved:
NuttShell (NSH) NuttX-9.1.0
nsh> mount
/etc type romfs
/proc type procfs
/tmp type vfat
nsh> ls -Rl /etc
/etc:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 20 group
dr-xr-xr-x 0 init.d/
-r-xr-xr-x 35 passwd
/etc/init.d:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 71 rcS
nsh> ls -l /etc/init.d
/etc/init.d:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 71 rcS
nsh> ls -l /etc/init.d/.
/etc/init.d/.:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 71 rcS
nsh> ls -l /etc/init.d/..
/etc/init.d/..:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 20 group
dr-xr-xr-x 0 init.d/
-r-xr-xr-x 35 passwd
nsh> ls -l /etc/init.d/../.
/etc/init.d/../.:
dr-xr-xr-x 0 .
dr-xr-xr-x 0 ..
-r-xr-xr-x 20 group
dr-xr-xr-x 0 init.d/
-r-xr-xr-x 35 passwd
nsh>
* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
sched/semaphore: Add nxsem_post() which is identical to sem_post() except that it never modifies the errno variable. Changed all references to sem_post in the OS to nxsem_post().
sched/semaphore: Add nxsem_destroy() which is identical to sem_destroy() except that it never modifies the errno variable. Changed all references to sem_destroy() in the OS to nxsem_destroy().
libc/semaphore and sched/semaphore: Add nxsem_getprotocol() and nxsem_setprotocola which are identical to sem_getprotocol() and set_setprotocol() except that they never modifies the errno variable. Changed all references to sem_setprotocol in the OS to nxsem_setprotocol(). sem_getprotocol() was not used in the OS
