From eaa0f2496700c238e7e3c112d36445f3aee06ff1 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 3 Jun 2020 19:17:19 -0400
Subject: move __expand_heap into malloc.c

this function is no longer used elsewhere, and moving it reduces the
number of source files specific to the malloc implementation.
---
 src/malloc/expand_heap.c | 71 ------------------------------------------------
 1 file changed, 71 deletions(-)
 delete mode 100644 src/malloc/expand_heap.c

(limited to 'src/malloc/expand_heap.c')

diff --git a/src/malloc/expand_heap.c b/src/malloc/expand_heap.c
deleted file mode 100644
index e6a3d7a0..00000000
--- a/src/malloc/expand_heap.c
+++ /dev/null
@@ -1,71 +0,0 @@
-#include <limits.h>
-#include <stdint.h>
-#include <errno.h>
-#include <sys/mman.h>
-#include "libc.h"
-#include "syscall.h"
-#include "malloc_impl.h"
-
-/* This function returns true if the interval [old,new]
- * intersects the 'len'-sized interval below &libc.auxv
- * (interpreted as the main-thread stack) or below &b
- * (the current stack). It is used to defend against
- * buggy brk implementations that can cross the stack. */
-
-static int traverses_stack_p(uintptr_t old, uintptr_t new)
-{
-	const uintptr_t len = 8<<20;
-	uintptr_t a, b;
-
-	b = (uintptr_t)libc.auxv;
-	a = b > len ? b-len : 0;
-	if (new>a && old<b) return 1;
-
-	b = (uintptr_t)&b;
-	a = b > len ? b-len : 0;
-	if (new>a && old<b) return 1;
-
-	return 0;
-}
-
-/* Expand the heap in-place if brk can be used, or otherwise via mmap,
- * using an exponential lower bound on growth by mmap to make
- * fragmentation asymptotically irrelevant. The size argument is both
- * an input and an output, since the caller needs to know the size
- * allocated, which will be larger than requested due to page alignment
- * and mmap minimum size rules. The caller is responsible for locking
- * to prevent concurrent calls. */
-
-void *__expand_heap(size_t *pn)
-{
-	static uintptr_t brk;
-	static unsigned mmap_step;
-	size_t n = *pn;
-
-	if (n > SIZE_MAX/2 - PAGE_SIZE) {
-		errno = ENOMEM;
-		return 0;
-	}
-	n += -n & PAGE_SIZE-1;
-
-	if (!brk) {
-		brk = __syscall(SYS_brk, 0);
-		brk += -brk & PAGE_SIZE-1;
-	}
-
-	if (n < SIZE_MAX-brk && !traverses_stack_p(brk, brk+n)
-	    && __syscall(SYS_brk, brk+n)==brk+n) {
-		*pn = n;
-		brk += n;
-		return (void *)(brk-n);
-	}
-
-	size_t min = (size_t)PAGE_SIZE << mmap_step/2;
-	if (n < min) n = min;
-	void *area = __mmap(0, n, PROT_READ|PROT_WRITE,
-		MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
-	if (area == MAP_FAILED) return 0;
-	*pn = n;
-	mmap_step++;
-	return area;
-}
-- 
cgit 1.4.1