diff options
author | Rich Felker <dalias@aerifal.cx> | 2020-06-29 17:41:24 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2020-06-29 17:42:53 -0400 |
commit | 785752a595ddd382396363f8aa237d1246ed5764 (patch) | |
tree | efb33e55bfe427ba666832a032c53cff0c131544 /src/malloc/mallocng/donate.c | |
parent | fdf8b2ad9c5ae6adf3a91c0043eb898badee46d1 (diff) | |
download | musl-785752a595ddd382396363f8aa237d1246ed5764.tar.gz |
add glue code for mallocng merge
this includes both an implementation of reclaimed-gap donation from
ldso and a version of mallocng's glue.h with namespace-safe linkage to
underlying syscalls, integration with AT_RANDOM initialization, and
internal locking that's optimized out when the process is
single-threaded.
Diffstat (limited to 'src/malloc/mallocng/donate.c')
-rw-r--r-- | src/malloc/mallocng/donate.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/src/malloc/mallocng/donate.c b/src/malloc/mallocng/donate.c new file mode 100644 index 00000000..41d850f3 --- /dev/null +++ b/src/malloc/mallocng/donate.c @@ -0,0 +1,39 @@ +#include <stdlib.h> +#include <stdint.h> +#include <limits.h> +#include <string.h> +#include <sys/mman.h> +#include <errno.h> + +#include "meta.h" + +static void donate(unsigned char *base, size_t len) +{ + uintptr_t a = (uintptr_t)base; + uintptr_t b = a + len; + a += -a & (UNIT-1); + b -= b & (UNIT-1); + memset(base, 0, len); + for (int sc=47; sc>0 && b>a; sc-=4) { + if (b-a < (size_classes[sc]+1)*UNIT) continue; + struct meta *m = alloc_meta(); + m->avail_mask = 0; + m->freed_mask = 1; + m->mem = (void *)a; + m->mem->meta = m; + m->last_idx = 0; + m->freeable = 0; + m->sizeclass = sc; + m->maplen = 0; + *((unsigned char *)m->mem+UNIT-4) = 0; + *((unsigned char *)m->mem+UNIT-3) = 255; + m->mem->storage[size_classes[sc]*UNIT-4] = 0; + queue(&ctx.active[sc], m); + a += (size_classes[sc]+1)*UNIT; + } +} + +void __malloc_donate(char *start, char *end) +{ + donate((void *)start, end-start); +} |