diff options
author | Florian Weimer <fweimer@redhat.com> | 2016-10-28 16:26:57 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2016-10-28 16:45:45 +0200 |
commit | e9c4fe93b3855239752819303ca377dff0ed0553 (patch) | |
tree | a6699b660d68aca544292661543b27b95dda4daf /malloc | |
parent | 4725d33eed118d69b8110285f7741cde9ddc8b4f (diff) | |
download | glibc-e9c4fe93b3855239752819303ca377dff0ed0553.tar.gz glibc-e9c4fe93b3855239752819303ca377dff0ed0553.tar.xz glibc-e9c4fe93b3855239752819303ca377dff0ed0553.zip |
malloc: Use accessors for chunk metadata access
This change allows us to change the encoding of these struct members in a centralized fashion.
Diffstat (limited to 'malloc')
-rw-r--r-- | malloc/arena.c | 6 | ||||
-rw-r--r-- | malloc/hooks.c | 8 | ||||
-rw-r--r-- | malloc/malloc.c | 147 |
3 files changed, 91 insertions, 70 deletions
diff --git a/malloc/arena.c b/malloc/arena.c index 976048370a..eed42471a7 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -122,7 +122,7 @@ int __malloc_initialized = -1; #define heap_for_ptr(ptr) \ ((heap_info *) ((unsigned long) (ptr) & ~(HEAP_MAX_SIZE - 1))) #define arena_for_chunk(ptr) \ - (chunk_non_main_arena (ptr) ? heap_for_ptr (ptr)->ar_ptr : &main_arena) + (chunk_main_arena (ptr) ? &main_arena : heap_for_ptr (ptr)->ar_ptr) /**************************************************************************/ @@ -560,12 +560,12 @@ heap_trim (heap_info *heap, size_t pad) /* fencepost must be properly aligned. */ misalign = ((long) p) & MALLOC_ALIGN_MASK; p = chunk_at_offset (prev_heap, prev_size - misalign); - assert (p->size == (0 | PREV_INUSE)); /* must be fencepost */ + assert (chunksize_nomask (p) == (0 | PREV_INUSE)); /* must be fencepost */ p = prev_chunk (p); new_size = chunksize (p) + (MINSIZE - 2 * SIZE_SZ) + misalign; assert (new_size > 0 && new_size < (long) (2 * MINSIZE)); if (!prev_inuse (p)) - new_size += p->prev_size; + new_size += prev_size (p); assert (new_size > 0 && new_size < HEAP_MAX_SIZE); if (new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz) break; diff --git a/malloc/hooks.c b/malloc/hooks.c index ecfe9c1b86..12995d3f0c 100644 --- a/malloc/hooks.c +++ b/malloc/hooks.c @@ -192,7 +192,7 @@ mem2chunk_check (void *mem, unsigned char **magic_p) ((char *) p < mp_.sbrk_base || ((char *) p + sz) >= (mp_.sbrk_base + main_arena.system_mem))) || sz < MINSIZE || sz & MALLOC_ALIGN_MASK || !inuse (p) || - (!prev_inuse (p) && (p->prev_size & MALLOC_ALIGN_MASK || + (!prev_inuse (p) && ((prev_size (p) & MALLOC_ALIGN_MASK) != 0 || (contig && (char *) prev_chunk (p) < mp_.sbrk_base) || next_chunk (prev_chunk (p)) != p))) return NULL; @@ -215,9 +215,9 @@ mem2chunk_check (void *mem, unsigned char **magic_p) offset != 0x20 && offset != 0x40 && offset != 0x80 && offset != 0x100 && offset != 0x200 && offset != 0x400 && offset != 0x800 && offset != 0x1000 && offset < 0x2000) || - !chunk_is_mmapped (p) || (p->size & PREV_INUSE) || - ((((unsigned long) p - p->prev_size) & page_mask) != 0) || - ((p->prev_size + sz) & page_mask) != 0) + !chunk_is_mmapped (p) || prev_inuse (p) || + ((((unsigned long) p - prev_size (p)) & page_mask) != 0) || + ((prev_size (p) + sz) & page_mask) != 0) return NULL; for (sz -= 1; (c = ((unsigned char *) p)[sz]) != magic; sz -= c) diff --git a/malloc/malloc.c b/malloc/malloc.c index e99fca0a51..f3378b90ed 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -1040,8 +1040,8 @@ static void* memalign_check(size_t alignment, size_t bytes, struct malloc_chunk { - INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ - INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ + INTERNAL_SIZE_T mchunk_prev_size; /* Size of previous chunk (if free). */ + INTERNAL_SIZE_T mchunk_size; /* Size in bytes, including overhead. */ struct malloc_chunk* fd; /* double links -- used only if free. */ struct malloc_chunk* bk; @@ -1200,14 +1200,14 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #define PREV_INUSE 0x1 /* extract inuse bit of previous chunk */ -#define prev_inuse(p) ((p)->size & PREV_INUSE) +#define prev_inuse(p) ((p)->mchunk_size & PREV_INUSE) /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ #define IS_MMAPPED 0x2 /* check for mmap()'ed chunk */ -#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) +#define chunk_is_mmapped(p) ((p)->mchunk_size & IS_MMAPPED) /* size field is or'ed with NON_MAIN_ARENA if the chunk was obtained @@ -1216,7 +1216,10 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #define NON_MAIN_ARENA 0x4 /* check for chunk from non-main arena */ -#define chunk_non_main_arena(p) ((p)->size & NON_MAIN_ARENA) +#define chunk_main_arena(p) (((p)->mchunk_size & NON_MAIN_ARENA) == 0) + +/* Mark a chunk as not being on the main arena. */ +#define set_non_main_arena(p) ((p)->mchunk_size |= NON_MAIN_ARENA) /* @@ -1230,51 +1233,62 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #define SIZE_BITS (PREV_INUSE | IS_MMAPPED | NON_MAIN_ARENA) /* Get size, ignoring use bits */ -#define chunksize(p) ((p)->size & ~(SIZE_BITS)) +#define chunksize(p) (chunksize_nomask (p) & ~(SIZE_BITS)) +/* Like chunksize, but do not mask SIZE_BITS. */ +#define chunksize_nomask(p) ((p)->mchunk_size) /* Ptr to next physical malloc_chunk. */ -#define next_chunk(p) ((mchunkptr) (((char *) (p)) + ((p)->size & ~SIZE_BITS))) +#define next_chunk(p) ((mchunkptr) (((char *) (p)) + chunksize (p))) + +/* Size of the chunk below P. Only valid if prev_inuse (P). */ +#define prev_size(p) ((p)->mchunk_prev_size) + +/* Set the size of the chunk below P. Only valid if prev_inuse (P). */ +#define set_prev_size(p, sz) ((p)->mchunk_prev_size = (sz)) -/* Ptr to previous physical malloc_chunk */ -#define prev_chunk(p) ((mchunkptr) (((char *) (p)) - ((p)->prev_size))) +/* Ptr to previous physical malloc_chunk. Only valid if prev_inuse (P). */ +#define prev_chunk(p) ((mchunkptr) (((char *) (p)) - prev_size (p))) /* Treat space at ptr + offset as a chunk */ #define chunk_at_offset(p, s) ((mchunkptr) (((char *) (p)) + (s))) /* extract p's inuse bit */ #define inuse(p) \ - ((((mchunkptr) (((char *) (p)) + ((p)->size & ~SIZE_BITS)))->size) & PREV_INUSE) + ((((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size) & PREV_INUSE) /* set/clear chunk as being inuse without otherwise disturbing */ #define set_inuse(p) \ - ((mchunkptr) (((char *) (p)) + ((p)->size & ~SIZE_BITS)))->size |= PREV_INUSE + ((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size |= PREV_INUSE #define clear_inuse(p) \ - ((mchunkptr) (((char *) (p)) + ((p)->size & ~SIZE_BITS)))->size &= ~(PREV_INUSE) + ((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size &= ~(PREV_INUSE) /* check/set/clear inuse bits in known places */ #define inuse_bit_at_offset(p, s) \ - (((mchunkptr) (((char *) (p)) + (s)))->size & PREV_INUSE) + (((mchunkptr) (((char *) (p)) + (s)))->mchunk_size & PREV_INUSE) #define set_inuse_bit_at_offset(p, s) \ - (((mchunkptr) (((char *) (p)) + (s)))->size |= PREV_INUSE) + (((mchunkptr) (((char *) (p)) + (s)))->mchunk_size |= PREV_INUSE) #define clear_inuse_bit_at_offset(p, s) \ - (((mchunkptr) (((char *) (p)) + (s)))->size &= ~(PREV_INUSE)) + (((mchunkptr) (((char *) (p)) + (s)))->mchunk_size &= ~(PREV_INUSE)) /* Set size at head, without disturbing its use bit */ -#define set_head_size(p, s) ((p)->size = (((p)->size & SIZE_BITS) | (s))) +#define set_head_size(p, s) ((p)->mchunk_size = (((p)->mchunk_size & SIZE_BITS) | (s))) /* Set size/use field */ -#define set_head(p, s) ((p)->size = (s)) +#define set_head(p, s) ((p)->mchunk_size = (s)) /* Set size at footer (only when chunk is not in use) */ -#define set_foot(p, s) (((mchunkptr) ((char *) (p) + (s)))->prev_size = (s)) +#define set_foot(p, s) (((mchunkptr) ((char *) (p) + (s)))->mchunk_prev_size = (s)) +#pragma GCC poison mchunk_size +#pragma GCC poison mchunk_prev_size + /* -------------------- Internal data structures -------------------- @@ -1349,7 +1363,7 @@ typedef struct malloc_chunk *mbinptr; else { \ FD->bk = BK; \ BK->fd = FD; \ - if (!in_smallbin_range (P->size) \ + if (!in_smallbin_range (chunksize_nomask (P)) \ && __builtin_expect (P->fd_nextsize != NULL, 0)) { \ if (__builtin_expect (P->fd_nextsize->bk_nextsize != P, 0) \ || __builtin_expect (P->bk_nextsize->fd_nextsize != P, 0)) \ @@ -1901,7 +1915,7 @@ do_check_chunk (mstate av, mchunkptr p) assert (((char *) p) < min_address || ((char *) p) >= max_address); } /* chunk is page-aligned */ - assert (((p->prev_size + sz) & (GLRO (dl_pagesize) - 1)) == 0); + assert (((prev_size (p) + sz) & (GLRO (dl_pagesize) - 1)) == 0); /* mem is aligned */ assert (aligned_OK (chunk2mem (p))); } @@ -1929,7 +1943,7 @@ do_check_free_chunk (mstate av, mchunkptr p) assert ((sz & MALLOC_ALIGN_MASK) == 0); assert (aligned_OK (chunk2mem (p))); /* ... matching footer field */ - assert (next->prev_size == sz); + assert (prev_size (p) == sz); /* ... and is fully consolidated */ assert (prev_inuse (p)); assert (next == av->top || inuse (next)); @@ -1994,10 +2008,10 @@ do_check_remalloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s) if (!chunk_is_mmapped (p)) { assert (av == arena_for_chunk (p)); - if (chunk_non_main_arena (p)) - assert (av != &main_arena); - else + if (chunk_main_arena (p)) assert (av == &main_arena); + else + assert (av != &main_arena); } do_check_inuse_chunk (av, p); @@ -2286,7 +2300,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) { correction = MALLOC_ALIGNMENT - front_misalign; p = (mchunkptr) (mm + correction); - p->prev_size = correction; + set_prev_size (p, correction); set_head (p, (size - correction) | IS_MMAPPED); } else @@ -2641,11 +2655,10 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) intentional. We need the fencepost, even if old_top otherwise gets lost. */ - chunk_at_offset (old_top, old_size)->size = - (2 * SIZE_SZ) | PREV_INUSE; - - chunk_at_offset (old_top, old_size + 2 * SIZE_SZ)->size = - (2 * SIZE_SZ) | PREV_INUSE; + set_head (chunk_at_offset (old_top, old_size), + (2 * SIZE_SZ) | PREV_INUSE); + set_head (chunk_at_offset (old_top, old_size + 2 * SIZE_SZ), + (2 * SIZE_SZ) | PREV_INUSE); /* If possible, release the rest. */ if (old_size >= MINSIZE) @@ -2773,8 +2786,8 @@ munmap_chunk (mchunkptr p) if (DUMPED_MAIN_ARENA_CHUNK (p)) return; - uintptr_t block = (uintptr_t) p - p->prev_size; - size_t total_size = p->prev_size + size; + uintptr_t block = (uintptr_t) p - prev_size (p); + size_t total_size = prev_size (p) + size; /* Unfortunately we have to do the compilers job by hand here. Normally we would test BLOCK and TOTAL-SIZE separately for compliance with the page size. But gcc does not recognize the optimization possibility @@ -2803,7 +2816,7 @@ internal_function mremap_chunk (mchunkptr p, size_t new_size) { size_t pagesize = GLRO (dl_pagesize); - INTERNAL_SIZE_T offset = p->prev_size; + INTERNAL_SIZE_T offset = prev_size (p); INTERNAL_SIZE_T size = chunksize (p); char *cp; @@ -2827,7 +2840,7 @@ mremap_chunk (mchunkptr p, size_t new_size) assert (aligned_OK (chunk2mem (p))); - assert ((p->prev_size == offset)); + assert (prev_size (p) == offset); set_head (p, (new_size - offset) | IS_MMAPPED); INTERNAL_SIZE_T new; @@ -2896,8 +2909,8 @@ __libc_free (void *mem) /* See if the dynamic brk/mmap threshold needs adjusting. Dumped fake mmapped chunks do not affect the threshold. */ if (!mp_.no_dyn_threshold - && p->size > mp_.mmap_threshold - && p->size <= DEFAULT_MMAP_THRESHOLD_MAX + && chunksize_nomask (p) > mp_.mmap_threshold + && chunksize_nomask (p) <= DEFAULT_MMAP_THRESHOLD_MAX && !DUMPED_MAIN_ARENA_CHUNK (p)) { mp_.mmap_threshold = chunksize (p); @@ -3389,7 +3402,7 @@ _int_malloc (mstate av, size_t bytes) bck->fd = bin; if (av != &main_arena) - victim->size |= NON_MAIN_ARENA; + set_non_main_arena (victim); check_malloced_chunk (av, victim, nb); void *p = chunk2mem (victim); alloc_perturb (p, bytes); @@ -3435,8 +3448,9 @@ _int_malloc (mstate av, size_t bytes) while ((victim = unsorted_chunks (av)->bk) != unsorted_chunks (av)) { bck = victim->bk; - if (__builtin_expect (victim->size <= 2 * SIZE_SZ, 0) - || __builtin_expect (victim->size > av->system_mem, 0)) + if (__builtin_expect (chunksize_nomask (victim) <= 2 * SIZE_SZ, 0) + || __builtin_expect (chunksize_nomask (victim) + > av->system_mem, 0)) malloc_printerr (check_action, "malloc(): memory corruption", chunk2mem (victim), av); size = chunksize (victim); @@ -3487,7 +3501,7 @@ _int_malloc (mstate av, size_t bytes) { set_inuse_bit_at_offset (victim, size); if (av != &main_arena) - victim->size |= NON_MAIN_ARENA; + set_non_main_arena (victim); check_malloced_chunk (av, victim, nb); void *p = chunk2mem (victim); alloc_perturb (p, bytes); @@ -3514,8 +3528,9 @@ _int_malloc (mstate av, size_t bytes) /* Or with inuse bit to speed comparisons */ size |= PREV_INUSE; /* if smaller than smallest, bypass loop below */ - assert ((bck->bk->size & NON_MAIN_ARENA) == 0); - if ((unsigned long) (size) < (unsigned long) (bck->bk->size)) + assert (chunk_main_arena (bck->bk)); + if ((unsigned long) (size) + < (unsigned long) chunksize_nomask (bck->bk)) { fwd = bck; bck = bck->bk; @@ -3526,14 +3541,15 @@ _int_malloc (mstate av, size_t bytes) } else { - assert ((fwd->size & NON_MAIN_ARENA) == 0); - while ((unsigned long) size < fwd->size) + assert (chunk_main_arena (fwd)); + while ((unsigned long) size < chunksize_nomask (fwd)) { fwd = fwd->fd_nextsize; - assert ((fwd->size & NON_MAIN_ARENA) == 0); + assert (chunk_main_arena (fwd)); } - if ((unsigned long) size == (unsigned long) fwd->size) + if ((unsigned long) size + == (unsigned long) chunksize_nomask (fwd)) /* Always insert in the second position. */ fwd = fwd->fd; else @@ -3571,8 +3587,9 @@ _int_malloc (mstate av, size_t bytes) bin = bin_at (av, idx); /* skip scan if empty or largest chunk is too small */ - if ((victim = first (bin)) != bin && - (unsigned long) (victim->size) >= (unsigned long) (nb)) + if ((victim = first (bin)) != bin + && (unsigned long) chunksize_nomask (victim) + >= (unsigned long) (nb)) { victim = victim->bk_nextsize; while (((unsigned long) (size = chunksize (victim)) < @@ -3581,7 +3598,9 @@ _int_malloc (mstate av, size_t bytes) /* Avoid removing the first entry for a size so that the skip list does not have to be rerouted. */ - if (victim != last (bin) && victim->size == victim->fd->size) + if (victim != last (bin) + && chunksize_nomask (victim) + == chunksize_nomask (victim->fd)) victim = victim->fd; remainder_size = size - nb; @@ -3592,7 +3611,7 @@ _int_malloc (mstate av, size_t bytes) { set_inuse_bit_at_offset (victim, size); if (av != &main_arena) - victim->size |= NON_MAIN_ARENA; + set_non_main_arena (victim); } /* Split */ else @@ -3697,7 +3716,7 @@ _int_malloc (mstate av, size_t bytes) { set_inuse_bit_at_offset (victim, size); if (av != &main_arena) - victim->size |= NON_MAIN_ARENA; + set_non_main_arena (victim); } /* Split */ @@ -3859,7 +3878,8 @@ _int_free (mstate av, mchunkptr p, int have_lock) #endif ) { - if (__builtin_expect (chunk_at_offset (p, size)->size <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (chunk_at_offset (p, size)) + <= 2 * SIZE_SZ, 0) || __builtin_expect (chunksize (chunk_at_offset (p, size)) >= av->system_mem, 0)) { @@ -3870,7 +3890,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) || ({ assert (locked == 0); __libc_lock_lock (av->mutex); locked = 1; - chunk_at_offset (p, size)->size <= 2 * SIZE_SZ + chunksize_nomask (chunk_at_offset (p, size)) <= 2 * SIZE_SZ || chunksize (chunk_at_offset (p, size)) >= av->system_mem; })) { @@ -3954,7 +3974,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) } nextsize = chunksize(nextchunk); - if (__builtin_expect (nextchunk->size <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (nextchunk) <= 2 * SIZE_SZ, 0) || __builtin_expect (nextsize >= av->system_mem, 0)) { errstr = "free(): invalid next size (normal)"; @@ -3965,7 +3985,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) /* consolidate backward */ if (!prev_inuse(p)) { - prevsize = p->prev_size; + prevsize = prev_size (p); size += prevsize; p = chunk_at_offset(p, -((long) prevsize)); unlink(av, p, bck, fwd); @@ -4130,12 +4150,12 @@ static void malloc_consolidate(mstate av) nextp = p->fd; /* Slightly streamlined version of consolidation code in free() */ - size = p->size & ~(PREV_INUSE|NON_MAIN_ARENA); + size = chunksize (p); nextchunk = chunk_at_offset(p, size); nextsize = chunksize(nextchunk); if (!prev_inuse(p)) { - prevsize = p->prev_size; + prevsize = prev_size (p); size += prevsize; p = chunk_at_offset(p, -((long) prevsize)); unlink(av, p, bck, fwd); @@ -4210,7 +4230,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, const char *errstr = NULL; /* oldmem size */ - if (__builtin_expect (oldp->size <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (oldp) <= 2 * SIZE_SZ, 0) || __builtin_expect (oldsize >= av->system_mem, 0)) { errstr = "realloc(): invalid old size"; @@ -4226,7 +4246,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, next = chunk_at_offset (oldp, oldsize); INTERNAL_SIZE_T nextsize = chunksize (next); - if (__builtin_expect (next->size <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (next) <= 2 * SIZE_SZ, 0) || __builtin_expect (nextsize >= av->system_mem, 0)) { errstr = "realloc(): invalid next size"; @@ -4412,7 +4432,7 @@ _int_memalign (mstate av, size_t alignment, size_t bytes) /* For mmapped chunks, just adjust offset */ if (chunk_is_mmapped (p)) { - newp->prev_size = p->prev_size + leadsize; + set_prev_size (newp, prev_size (p) + leadsize); set_head (newp, newsize | IS_MMAPPED); return chunk2mem (newp); } @@ -5154,12 +5174,13 @@ __malloc_info (int options, FILE *fp) if (r != NULL) while (r != bin) { + size_t r_size = chunksize_nomask (r); ++sizes[NFASTBINS - 1 + i].count; - sizes[NFASTBINS - 1 + i].total += r->size; + sizes[NFASTBINS - 1 + i].total += r_size; sizes[NFASTBINS - 1 + i].from - = MIN (sizes[NFASTBINS - 1 + i].from, r->size); + = MIN (sizes[NFASTBINS - 1 + i].from, r_size); sizes[NFASTBINS - 1 + i].to = MAX (sizes[NFASTBINS - 1 + i].to, - r->size); + r_size); r = r->fd; } |