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-rw-r--r--payloads/libpayload/libc/malloc.c133
1 files changed, 110 insertions, 23 deletions
diff --git a/payloads/libpayload/libc/malloc.c b/payloads/libpayload/libc/malloc.c
index 6dc6aab138..24daf0e680 100644
--- a/payloads/libpayload/libc/malloc.c
+++ b/payloads/libpayload/libc/malloc.c
@@ -63,6 +63,7 @@ typedef unsigned int hdrtype_t;
#define IS_FREE(_h) (((_h) & (MAGIC | FLAG_FREE)) == (MAGIC | FLAG_FREE))
#define HAS_MAGIC(_h) (((_h) & MAGIC) == MAGIC)
+static int free_aligned(void* addr);
void print_malloc_map(void);
static void setup(void)
@@ -72,7 +73,7 @@ static void setup(void)
*((hdrtype_t *) hstart) = FREE_BLOCK(size);
}
-static void *alloc(int len, int align)
+static void *alloc(int len)
{
hdrtype_t header;
void *ptr = hstart;
@@ -92,20 +93,13 @@ static void *alloc(int len, int align)
header = *((hdrtype_t *) ptr);
int size = SIZE(header);
- if (!HAS_MAGIC(header)) {
+ if (!HAS_MAGIC(header) || size == 0) {
printf("memory allocator panic.\n");
halt();
}
if (header & FLAG_FREE) {
- int realaddr = (int)(ptr + HDRSIZE);
- int overhead = ((realaddr+align-1) & ~(align-1)) - realaddr;
- if (len + overhead <= size) {
- if (overhead != 0) {
- *((hdrtype_t *) ptr) = FREE_BLOCK(overhead - HDRSIZE);
- ptr += overhead;
- size -= overhead;
- }
+ if (len <= size) {
void *nptr = ptr + (HDRSIZE + len);
int nsize = size - (HDRSIZE + len);
@@ -171,6 +165,8 @@ void free(void *ptr)
{
hdrtype_t hdr;
+ if (free_aligned(ptr)) return;
+
ptr -= HDRSIZE;
/* Sanity check. */
@@ -193,13 +189,13 @@ void free(void *ptr)
void *malloc(size_t size)
{
- return alloc(size, 1);
+ return alloc(size);
}
void *calloc(size_t nmemb, size_t size)
{
size_t total = nmemb * size;
- void *ptr = alloc(total, 1);
+ void *ptr = alloc(total);
if (ptr)
memset(ptr, 0, total);
@@ -213,7 +209,7 @@ void *realloc(void *ptr, size_t size)
unsigned int osize;
if (ptr == NULL)
- return alloc(size, 1);
+ return alloc(size);
pptr = ptr - HDRSIZE;
@@ -229,7 +225,7 @@ void *realloc(void *ptr, size_t size)
* reallocated the new space.
*/
free(ptr);
- ret = alloc(size, 1);
+ ret = alloc(size);
/*
* if ret == NULL, then doh - failure.
@@ -244,23 +240,114 @@ void *realloc(void *ptr, size_t size)
return ret;
}
-/**
- * Allocate an aligned chunk of memory
- *
- * @param align alignment, must be power of two
- * @param size size of chunk in bytes
- * @return Return the address of such a memory region or NULL
- */
+struct align_region_t
+{
+ int alignment;
+ /* start in memory, and size in bytes */
+ void* start;
+ int size;
+ /* layout within a region:
+ - num_elements bytes, 0: free, 1: used, 2: used, combines with next
+ - padding to alignment
+ - data section
+ - waste space
+
+ start_data points to the start of the data section
+ */
+ void* start_data;
+ /* number of free blocks sized "alignment" */
+ int free;
+ struct align_region_t *next;
+};
+
+static struct align_region_t* align_regions = 0;
+
+static struct align_region_t *allocate_region(struct align_region_t *old_first, int alignment, int num_elements)
+{
+ struct align_region_t *new_region = malloc(sizeof(struct align_region_t));
+ new_region->alignment = alignment;
+ new_region->start = malloc((num_elements+1) * alignment + num_elements);
+ new_region->start_data = (void*)((u32)(new_region->start + num_elements + alignment - 1) & (~(alignment-1)));
+ new_region->size = num_elements * alignment;
+ new_region->free = num_elements;
+ new_region->next = old_first;
+ memset(new_region->start, 0, num_elements);
+ return new_region;
+}
+
+
+static int free_aligned(void* addr)
+{
+ struct align_region_t *reg = align_regions;
+ while (reg != 0)
+ {
+ if ((addr >= reg->start_data) && (addr < reg->start_data + reg->size))
+ {
+ int i = (addr-reg->start_data)/reg->alignment;
+ while (((u8*)reg->start)[i]==2)
+ {
+ ((u8*)reg->start)[i++]=0;
+ reg->free++;
+ }
+ ((u8*)reg->start)[i]=0;
+ reg->free++;
+ return 1;
+ }
+ reg = reg->next;
+ }
+ return 0;
+}
+
void *memalign(size_t align, size_t size)
{
- return alloc(size, align);
+ if (size == 0) return 0;
+ if (align_regions == 0) {
+ align_regions = malloc(sizeof(struct align_region_t));
+ memset(align_regions, 0, sizeof(struct align_region_t));
+ }
+ struct align_region_t *reg = align_regions;
+look_further:
+ while (reg != 0)
+ {
+ if ((reg->alignment == align) && (reg->free >= (size + align - 1)/align))
+ {
+ break;
+ }
+ reg = reg->next;
+ }
+ if (reg == 0)
+ {
+ align_regions = allocate_region(align_regions, align, (size/align<99)?100:((size/align)+1));
+ reg = align_regions;
+ }
+ int i, count = 0, target = (size+align-1)/align;
+ for (i = 0; i < (reg->size/align); i++)
+ {
+ if (((u8*)reg->start)[i] == 0)
+ {
+ count++;
+ if (count == target) {
+ count = i+1-count;
+ for (i=0; i<target-1; i++)
+ {
+ ((u8*)reg->start)[count+i]=2;
+ }
+ ((u8*)reg->start)[count+target-1]=1;
+ reg->free -= target;
+ return reg->start_data+(align*count);
+ }
+ } else {
+ count = 0;
+ }
+ }
+ goto look_further; // end condition is once a new region is allocated - it always has enough space
}
/* This is for debugging purposes. */
#ifdef TEST
void print_malloc_map(void)
{
-void *ptr = hstart;
+ void *ptr = hstart;
while (ptr < hend) {
hdrtype_t hdr = *((hdrtype_t *) ptr);