Editing C dynamic memory allocation (section)

===OpenBSD's malloc===
[[OpenBSD]]'s implementation of the <code>malloc</code> function makes use of [[mmap]]. For requests greater in size than one page, the entire allocation is retrieved using <code>mmap</code>; smaller sizes are assigned from memory pools maintained by <code>malloc</code> within a number of "bucket pages", also allocated with <code>mmap</code>.<ref>{{cite web|url=http://bxr.su/OpenBSD/lib/libc/stdlib/malloc.c |title=libc/stdlib/malloc.c |website=BSD Cross Reference, OpenBSD src/lib/}}</ref>{{better source needed|date=November 2015}} On a call to <code>free</code>, memory is released and unmapped from the process [[address space]] using <code>munmap</code>. This system is designed to improve security by taking advantage of the [[address space layout randomization]] and gap page features implemented as part of OpenBSD's <code>mmap</code> [[system call]], and to detect use-after-free bugs—as a large memory allocation is completely unmapped after it is freed, further use causes a [[segmentation fault]] and termination of the program.

The GrapheneOS project initially started out by porting OpenBSD's memory allocator to Android's Bionic C Library.<ref>{{Cite web |title=History {{!}} GrapheneOS |url=https://grapheneos.org/history/ |access-date=2023-03-02 |website=grapheneos.org |language=en}}</ref>

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