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Fix stdin fake mremap creating null bytes on osx, patch courtesy of John Boyle.

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Con Kolivas 2013-09-01 08:43:28 +10:00
parent 2c1dda7b73
commit 37ef39e70a
1 changed files with 15 additions and 2 deletions
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17
rzip.c
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@ -774,8 +774,21 @@ static inline void init_hash_indexes(struct rzip_state *st)
static inline void *fake_mremap(void *old_address, size_t old_size, size_t new_size, int flags __UNUSED__)
{
munmap(old_address, old_size);
return mmap(old_address, new_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
if (new_size > old_size) {
fprintf(stderr, "fake_mremap: This should only be used to shrink things. I'm not bothering with this.\n");
exit(1);
} else {
/* new_size occupies N pages; old_size occupies M > N pages;
we want to unmap the M - N pages at the end.
note the idiom: ceiling(n/k) = (n+k-1) div k */
size_t kept_n = (new_size + PAGE_SIZE - 1) / PAGE_SIZE;
int ret = munmap(old_address + (kept_n * PAGE_SIZE), old_size - (kept_n * PAGE_SIZE));
if (ret < 0)
return MAP_FAILED;
return old_address;
}
}
/* stdin is not file backed so we have to emulate the mmap by mapping