Test on sim/nsh:
(CONFIG_DEBUG_ASSERTIONS=y CONFIG_DEFAULT_SMALL=y)
text data bss dec hex filename
423626 27152 4128 454906 6f0fa nuttx /* before */
417010 27152 4128 448290 6d722 nuttx /* after */
-6616
Signed-off-by: chao an <anchao@xiaomi.com>
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>
Updated alt1250 driver with regarding to the following changes.
- Add LTE hibernation feature
- Split source code per module
- Some refactoring
- Some bug fixes
This adds functionality to map pages dynamically into kernel virtual
memory. This allows implementing I/O remap for example, which is a useful
(future) feature.
Now, the first target is to support mapping user pages for the kernel.
Why? There are some userspace structures that might be needed when the
userspace process is not running. Semaphores are one such example. Signals
and the WDT timeout both need access to the user semaphore to work
properly. Even though for this only obtaining the kernel addressable
page pool virtual address is needed, for completeness a procedure is
provided to map several pages.
Add a new field to record the global on the basis of mm_backtrace.
When using alloc, the field is incremented by 1,
so that the memory usage can be dumped within the range
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
if multiple threads are doing serial read/write at the same time,
the driver will only wake up one of the thread, which will cause
other threads fail to be woken up in time and cause blocking
Signed-off-by: chao an <anchao@xiaomi.com>
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>
