Based on 5e592c66bdf76dfc8445b332f7a5088ca504ee90 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Fri, 4 Jul 2014 19:53:58 -0400 Subject: [PATCH] journal/compress: return early in uncompress_startswith uncompress_startswith would always decode the whole stream, even if it did not start with the given prefix. Reallocation policy was also strange. --- src/journal/compress.c | 91 ++++++++++++++----------------------------------- 1 file changed, 27 insertions(+), 64 deletions(-) --- src/journal/compress.c +++ src/journal/compress.c 2014-07-09 00:00:00.000000000 +0000 @@ -69,10 +69,9 @@ fail: 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); @@ -85,26 +84,18 @@ bool uncompress_blob(const void *src, ui 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); @@ -112,31 +103,25 @@ bool uncompress_blob(const void *src, ui 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; - - s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *dst); - s.avail_out += space; + if (dst_max > 0 && space == dst_max) + return false; - space *= 2; + 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; - *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, @@ -144,9 +129,8 @@ bool uncompress_startswith(const void *s 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 @@ -163,16 +147,8 @@ bool uncompress_startswith(const void *s 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; @@ -181,36 +157,23 @@ bool uncompress_startswith(const void *s 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; - - p = realloc(*buffer, *buffer_size*2); - if (!p) - goto fail; + return false; - s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *buffer); s.avail_out += *buffer_size; - *buffer = p; - *buffer_size *= 2; - } - - b = true; - -fail: - lzma_end(&s); + if (!(greedy_realloc(buffer, buffer_size, *buffer_size * 2, 1))) + return false; - return b; + s.next_out = *buffer + *buffer_size - s.avail_out; + } }