In embedded development environments, due to the lack of address isolation between processes,
fd may be passed between processes and lead to misuse,
We have designed an fd cross-process automatic detection tool,
fdcheck_protect returns the fd containing the pid information,
indicating that the ownership of the current fd belongs to the pid and is not allowed to be used by other processes.
fdcheck_restore will obtain the true fd and check if the ownership of the fd is legal
For ease of understanding, let's give an example where
the following information is represented in 32-bit binary format
fd 00000000 00000000 00000000 10001010
pid 00000000 00000000 00000011 01010101
ret 00000000 00000011 01010101 10001010
Signed-off-by: hujun5 <hujun5@xiaomi.com>
Fix bug that select() did not return when the nfds argument
was set to a negative value. The specification is that -1 is
set to the return value and EINVAL is set to errno.
* 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
arch/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
sched/ audio/ crypto/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
Documentation/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
fs/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
graphics/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
net/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
drivers/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
include/, syscall/, wireless/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
configs/: Remove all references to CONFIG_DISABLE_POLL. Standard POSIX poll can no longer be disabled.
