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authorRich Felker <dalias@aerifal.cx>2011-02-20 16:16:33 -0500
committerRich Felker <dalias@aerifal.cx>2011-02-20 16:16:33 -0500
commit26031da0f83a2a3ed52190077931ee6c18dfd689 (patch)
treef1cefeef545766d941e9f0fe1377e9db46ce8aad /src/malloc
parent598a0147cde14d093d17b81c102a1757b5ef9975 (diff)
downloadmusl-26031da0f83a2a3ed52190077931ee6c18dfd689.tar.gz
make malloc(0) return unique pointers rather than NULL
this change is made with some reluctance, but i think it's for the best. correct programs must handle either behavior, so there is little advantage to having malloc(0) return NULL. and i managed to actually make the malloc code slightly smaller with this change.
Diffstat (limited to 'src/malloc')
-rw-r--r--src/malloc/__simple_malloc.c2
-rw-r--r--src/malloc/malloc.c14
2 files changed, 10 insertions, 6 deletions
diff --git a/src/malloc/__simple_malloc.c b/src/malloc/__simple_malloc.c
index c029342c..c8293908 100644
--- a/src/malloc/__simple_malloc.c
+++ b/src/malloc/__simple_malloc.c
@@ -15,7 +15,7 @@ void *__simple_malloc(size_t n)
static int lock;
size_t align=1;
- if (!n) return 0;
+ if (!n) n++;
if (n > SIZE_MAX/2) goto toobig;
while (align<n && align<ALIGN)
diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index d9a30fe4..3c08c41e 100644
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -216,9 +216,14 @@ static int init_malloc()
static int adjust_size(size_t *n)
{
/* Result of pointer difference must fit in ptrdiff_t. */
- if (*n > PTRDIFF_MAX - SIZE_ALIGN - PAGE_SIZE) {
- errno = ENOMEM;
- return -1;
+ if (*n-1 > PTRDIFF_MAX - SIZE_ALIGN - PAGE_SIZE) {
+ if (*n) {
+ errno = ENOMEM;
+ return -1;
+ } else {
+ *n = SIZE_ALIGN;
+ return 0;
+ }
}
*n = (*n + OVERHEAD + SIZE_ALIGN - 1) & SIZE_MASK;
return 0;
@@ -325,7 +330,7 @@ void *malloc(size_t n)
struct chunk *c;
int i, j;
- if (!n || adjust_size(&n) < 0) return 0;
+ if (adjust_size(&n) < 0) return 0;
if (n > MMAP_THRESHOLD) {
size_t len = n + PAGE_SIZE - 1 & -PAGE_SIZE;
@@ -377,7 +382,6 @@ void *realloc(void *p, size_t n)
void *new;
if (!p) return malloc(n);
- else if (!n) return free(p), (void *)0;
if (adjust_size(&n) < 0) return 0;