diff options
Diffstat (limited to 'libffi/src/dlmalloc.c')
| -rw-r--r-- | libffi/src/dlmalloc.c | 58 |
1 files changed, 48 insertions, 10 deletions
diff --git a/libffi/src/dlmalloc.c b/libffi/src/dlmalloc.c index 809e19aa4e6..c95e64a7e37 100644 --- a/libffi/src/dlmalloc.c +++ b/libffi/src/dlmalloc.c @@ -1879,11 +1879,47 @@ struct malloc_segment { char* base; /* base address */ size_t size; /* allocated size */ struct malloc_segment* next; /* ptr to next segment */ +#if FFI_MMAP_EXEC_WRIT + /* The mmap magic is supposed to store the address of the executable + segment at the very end of the requested block. */ + +# define mmap_exec_offset(b,s) (*(ptrdiff_t*)((b)+(s)-sizeof(ptrdiff_t))) + + /* We can only merge segments if their corresponding executable + segments are at identical offsets. */ +# define check_segment_merge(S,b,s) \ + (mmap_exec_offset((b),(s)) == (S)->exec_offset) + +# define add_segment_exec_offset(p,S) ((char*)(p) + (S)->exec_offset) +# define sub_segment_exec_offset(p,S) ((char*)(p) - (S)->exec_offset) + + /* The removal of sflags only works with HAVE_MORECORE == 0. */ + +# define get_segment_flags(S) (IS_MMAPPED_BIT) +# define set_segment_flags(S,v) \ + (((v) != IS_MMAPPED_BIT) ? (ABORT, (v)) : \ + (((S)->exec_offset = \ + mmap_exec_offset((S)->base, (S)->size)), \ + (mmap_exec_offset((S)->base + (S)->exec_offset, (S)->size) != \ + (S)->exec_offset) ? (ABORT, (v)) : \ + (mmap_exec_offset((S)->base, (S)->size) = 0), (v))) + + /* We use an offset here, instead of a pointer, because then, when + base changes, we don't have to modify this. On architectures + with segmented addresses, this might not work. */ + ptrdiff_t exec_offset; +#else + +# define get_segment_flags(S) ((S)->sflags) +# define set_segment_flags(S,v) ((S)->sflags = (v)) +# define check_segment_merge(S,b,s) (1) + flag_t sflags; /* mmap and extern flag */ +#endif }; -#define is_mmapped_segment(S) ((S)->sflags & IS_MMAPPED_BIT) -#define is_extern_segment(S) ((S)->sflags & EXTERN_BIT) +#define is_mmapped_segment(S) (get_segment_flags(S) & IS_MMAPPED_BIT) +#define is_extern_segment(S) (get_segment_flags(S) & EXTERN_BIT) typedef struct malloc_segment msegment; typedef struct malloc_segment* msegmentptr; @@ -3290,7 +3326,7 @@ static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) { *ss = m->seg; /* Push current record */ m->seg.base = tbase; m->seg.size = tsize; - m->seg.sflags = mmapped; + set_segment_flags(&m->seg, mmapped); m->seg.next = ss; /* Insert trailing fenceposts */ @@ -3393,7 +3429,7 @@ static void* sys_alloc(mstate m, size_t nb) { if (end != CMFAIL) asize += esize; else { /* Can't use; try to release */ - CALL_MORECORE(-asize); + (void)CALL_MORECORE(-asize); br = CMFAIL; } } @@ -3450,7 +3486,7 @@ static void* sys_alloc(mstate m, size_t nb) { if (!is_initialized(m)) { /* first-time initialization */ m->seg.base = m->least_addr = tbase; m->seg.size = tsize; - m->seg.sflags = mmap_flag; + set_segment_flags(&m->seg, mmap_flag); m->magic = mparams.magic; init_bins(m); if (is_global(m)) @@ -3469,7 +3505,8 @@ static void* sys_alloc(mstate m, size_t nb) { sp = sp->next; if (sp != 0 && !is_extern_segment(sp) && - (sp->sflags & IS_MMAPPED_BIT) == mmap_flag && + check_segment_merge(sp, tbase, tsize) && + (get_segment_flags(sp) & IS_MMAPPED_BIT) == mmap_flag && segment_holds(sp, m->top)) { /* append */ sp->size += tsize; init_top(m, m->top, m->topsize + tsize); @@ -3482,7 +3519,8 @@ static void* sys_alloc(mstate m, size_t nb) { sp = sp->next; if (sp != 0 && !is_extern_segment(sp) && - (sp->sflags & IS_MMAPPED_BIT) == mmap_flag) { + check_segment_merge(sp, tbase, tsize) && + (get_segment_flags(sp) & IS_MMAPPED_BIT) == mmap_flag) { char* oldbase = sp->base; sp->base = tbase; sp->size += tsize; @@ -4397,7 +4435,7 @@ mspace create_mspace(size_t capacity, int locked) { char* tbase = (char*)(CALL_MMAP(tsize)); if (tbase != CMFAIL) { m = init_user_mstate(tbase, tsize); - m->seg.sflags = IS_MMAPPED_BIT; + set_segment_flags(&m->seg, IS_MMAPPED_BIT); set_lock(m, locked); } } @@ -4412,7 +4450,7 @@ mspace create_mspace_with_base(void* base, size_t capacity, int locked) { if (capacity > msize + TOP_FOOT_SIZE && capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) { m = init_user_mstate((char*)base, capacity); - m->seg.sflags = EXTERN_BIT; + set_segment_flags(&m->seg, EXTERN_BIT); set_lock(m, locked); } return (mspace)m; @@ -4426,7 +4464,7 @@ size_t destroy_mspace(mspace msp) { while (sp != 0) { char* base = sp->base; size_t size = sp->size; - flag_t flag = sp->sflags; + flag_t flag = get_segment_flags(sp); sp = sp->next; if ((flag & IS_MMAPPED_BIT) && !(flag & EXTERN_BIT) && CALL_MUNMAP(base, size) == 0) |