FD (file descriptor) is widely used in system software development,
and almost all implementations of posix os (including nuttx) use FD as an index.
the value of fd needs to be allocated starting from the minimum available value of 3, and each process has a copy,
so the same fd value is very easy to reuse in the program.
In multi threaded or multi process environments without address isolation,
If the ownership, global variables, and competition relationships of fd are not properly handled,
there may be issues with fd duplication or accidental closure.
Further leading to the following issues, which are difficult to troubleshoot.
1. Security vulnerability: the fd we wrote is not the expected fd and will be accessed by hackers to obtain data
2. Program exceptions or crashes: write or read fd failures, and program logic errors
3. The structured file XML or database is damaged: the data format written to the database is not the expected format.
The implementation principle of fdsan is based on the implementation of Android
https://android.googlesource.com/platform/bionic/+/master/docs/fdsan.md
Signed-off-by: hujun5 <hujun5@xiaomi.com>
The spawn proxy thread is a special existence in NuttX, usually some developers
spend a lot of time on stack overflow of spawn proxy thread:
https://github.com/apache/nuttx/issues/9046https://github.com/apache/nuttx/pull/9081
In order to avoid similar issues, this PR will remove spawn proxy thread to simplify
the process of task/posix_spawn().
1. Postpone the related processing of spawn file actions until after task_init()
2. Delete the temporary thread of spawn proxy and related global variables
Signed-off-by: chao an <anchao@xiaomi.com>
With flat addressing the user pollfd list is given directly to the
drivers that perform the notification. This is fine when the addressing
is flat, as there is no ambiguity on who gets notified and the fds memory
is always mapped.
For kernel mode with MMU this does not work. The notification must be done
via a temporary buffer allocated from kernel memory.
Thus, create a copy of the user fds and pass the copy to the drivers.
Afterwards copy the output events back to the user.
since mmap may exist in block_operations, but truncate may not,
moving mmap beforee truncate could make three struct more compatible
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
- Add mmap into file_operations and remove it from ioctl definitions.
- Add mm_map structure definitions to support future unmapping
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
- Add truncate into file_operations
- Move truncate to be common for mountpt_operations and file_operations
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
This is preparation for flushing streams from user space, like it should
be done.
- Move tg_streamlist (group, kernel space) ->
ta_streamlist (TLS, user space)
- Access stream list via tg_info in kernel
- Access stream list via TLS in user space
- Remove / rename nxsched_get_streams -> lib_getstreams
- Remove system call for nxsched_get_streams
nx_open in timerfd_create will increase reference count,
Therefore, the reference count starts with a value of 0.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
1. epoll_ctl(EPOLL_CTL_ADD) support extend the epoll
events dynamicly;
2. enhance the epoll performance by moving some poll setup
and teardown process to the EPOLL_CTL_ADD/DEL/MOD;
Signed-off-by: wangbowen6 <wangbowen6@xiaomi.com>
1.Don't check the return value of nxsem_init or nxmutex_init
2.Fix some style issue
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
