Add a flag to hook mmap

gmike

Sometimes, mmap is used specifically for memory allocation, but directly hooking mmap can lead to many issues. To handle this more effectively, we could assign a flag to indicate when mmap is being used for allocation purposes. By using this flag, we could dynamically adjust how we hook or bypass mmap based on the allocation context.

Such as:
#define MAP_HOOK 1 << 30
m_alloc_mem = mmap(nullptr, TOT_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HOOK, -1, 0);

I believe this is a feasible approach.

gmike

But, is using mmap to allocate memory a recommended practice?

ff07

I think a more flexible way for this would be LD_PRELOAD. See ld.so man page[1] and some talks[2] and demo video[3].

[1] https://man7.org/linux/man-pages/man8/ld.so.8.html
[2] https://youtu.be/nM9Y2Sky6S0
[3] https://youtu.be/KJPeZptzl1U

gmike

Thanks @ff07