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| author | Rich Felker <dalias@aerifal.cx> | 2021-01-30 17:28:08 -0500 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2021-01-30 17:28:08 -0500 |
| commit | 9b77aaca86b53c367f23505c24dd3c02e240efad (patch) | |
| tree | 7922f847a292971a7dbe61f68acd503d9a58a371 /src | |
| parent | 98b9df994c85dcb6a8a5a9099495dd44c7cf2bce (diff) | |
| download | musl-9b77aaca86b53c367f23505c24dd3c02e240efad.tar.gz musl-9b77aaca86b53c367f23505c24dd3c02e240efad.tar.xz musl-9b77aaca86b53c367f23505c24dd3c02e240efad.zip | |
oldmalloc: preserve errno across free
as an outcome of Austin Group issue #385, future versions of the standard will require free not to alter the value of errno. save and restore it individually around the calls to madvise and munmap so that the cost is not imposed on calls to free that do not result in any syscall.
Diffstat (limited to 'src')
| -rw-r--r-- | src/malloc/oldmalloc/malloc.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/malloc/oldmalloc/malloc.c b/src/malloc/oldmalloc/malloc.c index a5cbdb68..25d00d44 100644 --- a/src/malloc/oldmalloc/malloc.c +++ b/src/malloc/oldmalloc/malloc.c @@ -481,12 +481,14 @@ void __bin_chunk(struct chunk *self) if (size > RECLAIM && (size^(size-osize)) > size-osize) { uintptr_t a = (uintptr_t)self + SIZE_ALIGN+PAGE_SIZE-1 & -PAGE_SIZE; uintptr_t b = (uintptr_t)next - SIZE_ALIGN & -PAGE_SIZE; + int e = errno; #if 1 __madvise((void *)a, b-a, MADV_DONTNEED); #else __mmap((void *)a, b-a, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0); #endif + errno = e; } unlock_bin(i); @@ -499,7 +501,9 @@ static void unmap_chunk(struct chunk *self) size_t len = CHUNK_SIZE(self) + extra; /* Crash on double free */ if (extra & 1) a_crash(); + int e = errno; __munmap(base, len); + errno = e; } void free(void *p) |