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authorRich Felker <dalias@aerifal.cx>2020-06-03 19:17:19 -0400
committerRich Felker <dalias@aerifal.cx>2020-06-03 19:17:19 -0400
commiteaa0f2496700c238e7e3c112d36445f3aee06ff1 (patch)
tree41979600733c58af880b832bed70bc51814b2bc9
parente07138b880dcc72d3f1b3a2d2c1af75c2484c8d7 (diff)
downloadmusl-eaa0f2496700c238e7e3c112d36445f3aee06ff1.tar.gz
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.
-rw-r--r--src/malloc/expand_heap.c71
-rw-r--r--src/malloc/malloc.c64
-rw-r--r--src/malloc/malloc_impl.h2
3 files changed, 64 insertions, 73 deletions
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;
-}
diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index 20598ec3..df3ea1be 100644
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -126,6 +126,70 @@ void __dump_heap(int x)
}
#endif
+/* 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. */
+
+static 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;
+}
+
static struct chunk *expand_heap(size_t n)
{
static void *end;
diff --git a/src/malloc/malloc_impl.h b/src/malloc/malloc_impl.h
index 6a92c1c6..e1cf4774 100644
--- a/src/malloc/malloc_impl.h
+++ b/src/malloc/malloc_impl.h
@@ -4,8 +4,6 @@
#include <sys/mman.h>
#include "dynlink.h"
-hidden void *__expand_heap(size_t *);
-
struct chunk {
size_t psize, csize;
struct chunk *next, *prev;