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journal/compress: return early in uncompress_startswith

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uncompress_startswith would always decode the whole stream, even
if it did not start with the given prefix.

Reallocation policy was also strange.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2014-07-04 19:53:58 -04:00
parent abee28c56d
commit 5e592c66bd
1 changed files with 27 additions and 64 deletions
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91
src/journal/compress.c
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@ -57,10 +57,9 @@ bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_
bool uncompress_blob(const void *src, uint64_t src_size,
void **dst, uint64_t *dst_alloc_size, uint64_t* dst_size, uint64_t dst_max) {
lzma_stream s = LZMA_STREAM_INIT;
_cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
uint64_t space;
bool b = false;
assert(src);
assert(src_size > 0);
@ -73,26 +72,18 @@ bool uncompress_blob(const void *src, uint64_t src_size,
if (ret != LZMA_OK)
return false;
if (*dst_alloc_size <= src_size) {
void *p;
p = realloc(*dst, src_size*2);
if (!p)
return false;
*dst = p;
*dst_alloc_size = src_size*2;
}
space = MIN(src_size * 2, dst_max ?: (uint64_t) -1);
if (!greedy_realloc(dst, dst_alloc_size, space, 1))
return false;
s.next_in = src;
s.avail_in = src_size;
s.next_out = *dst;
space = dst_max > 0 ? MIN(*dst_alloc_size, dst_max) : *dst_alloc_size;
s.avail_out = space;
for (;;) {
void *p;
uint64_t used;
ret = lzma_code(&s, LZMA_FINISH);
@ -100,31 +91,25 @@ bool uncompress_blob(const void *src, uint64_t src_size,
break;
if (ret != LZMA_OK)
goto fail;
return false;
if (dst_max > 0 && (space - s.avail_out) >= dst_max)
break;
p = realloc(*dst, space*2);
if (!p)
goto fail;
if (dst_max > 0 && space == dst_max)
return false;
s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *dst);
s.avail_out += space;
used = space - s.avail_out;
space = MIN(2 * space, dst_max ?: (uint64_t) -1);
if (!greedy_realloc(dst, dst_alloc_size, space, 1))
return false;
space *= 2;
*dst = p;
*dst_alloc_size = space;
s.avail_out = space - used;
s.next_out = *dst + used;
}
*dst_size = space - s.avail_out;
b = true;
fail:
lzma_end(&s);
return b;
return true;
}
bool uncompress_startswith(const void *src, uint64_t src_size,
@ -132,9 +117,8 @@ bool uncompress_startswith(const void *src, uint64_t src_size,
const void *prefix, uint64_t prefix_len,
uint8_t extra) {
lzma_stream s = LZMA_STREAM_INIT;
_cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
bool b = false;
/* Checks whether the uncompressed blob starts with the
* mentioned prefix. The byte extra needs to follow the
@ -151,16 +135,8 @@ bool uncompress_startswith(const void *src, uint64_t src_size,
if (ret != LZMA_OK)
return false;
if (*buffer_size <= prefix_len) {
void *p;
p = realloc(*buffer, prefix_len*2);
if (!p)
return false;
*buffer = p;
*buffer_size = prefix_len*2;
}
if (!(greedy_realloc(buffer, buffer_size, prefix_len + 1, 1)))
return false;
s.next_in = src;
s.avail_in = src_size;
@ -169,38 +145,25 @@ bool uncompress_startswith(const void *src, uint64_t src_size,
s.avail_out = *buffer_size;
for (;;) {
void *p;
ret = lzma_code(&s, LZMA_FINISH);
if (ret != LZMA_STREAM_END && ret != LZMA_OK)
goto fail;
return false;
if ((*buffer_size - s.avail_out > prefix_len) &&
memcmp(*buffer, prefix, prefix_len) == 0 &&
((const uint8_t*) *buffer)[prefix_len] == extra)
break;
if (*buffer_size - s.avail_out >= prefix_len + 1)
return memcmp(*buffer, prefix, prefix_len) == 0 &&
((const uint8_t*) *buffer)[prefix_len] == extra;
if (ret == LZMA_STREAM_END)
goto fail;
return false;
p = realloc(*buffer, *buffer_size*2);
if (!p)
goto fail;
s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *buffer);
s.avail_out += *buffer_size;
*buffer = p;
*buffer_size *= 2;
if (!(greedy_realloc(buffer, buffer_size, *buffer_size * 2, 1)))
return false;
s.next_out = *buffer + *buffer_size - s.avail_out;
}
b = true;
fail:
lzma_end(&s);
return b;
}
int compress_stream(int fdf, int fdt, uint32_t preset, off_t max_bytes) {