From 5038c4b33ea403203b8edd82b44a8db06464409b Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Tue, 11 Jun 2019 01:24:57 +0200 Subject: Major cleanup of mkfs block processor This commit tries to make the block and fragment processing code a lot more readable by simplifying it as follows. The following pattern is used repeatedly: - Try to compress a block - Write the compressed if smaller (the original otherwise) to a file - Print errors on the way - Set the magic (1 << 24) flag if we wrote the original - Increment the super block byte counter => Move that to a seperate function called "write_compressed" => Move the code to grow the fragment table is moved to a seperate function. => Clearing the fragment buffer is pointless, so remove that The add_fragment/add_block functions are now trivial => Merge them into process_file => Global block counter no longer needed, so remove that too Signed-off-by: David Oberhollenzer --- mkfs/block.c | 117 +++++++++++++++++++++++------------------------------------ mkfs/mkfs.h | 2 - 2 files changed, 46 insertions(+), 73 deletions(-) (limited to 'mkfs') diff --git a/mkfs/block.c b/mkfs/block.c index eba8c24..f023876 100644 --- a/mkfs/block.c +++ b/mkfs/block.c @@ -2,50 +2,43 @@ #include "mkfs.h" #include "util.h" -static int write_block(file_info_t *fi, sqfs_info_t *info) +static int write_compressed(sqfs_info_t *info, const void *in, size_t size, + uint32_t *outsize) { - size_t idx, bs; ssize_t ret; - void *ptr; - idx = info->file_block_count++; - bs = info->super.block_size; - - ret = info->cmp->do_block(info->cmp, info->block, bs, - info->scratch, bs); + ret = info->cmp->do_block(info->cmp, in, size, info->scratch, + info->super.block_size); if (ret < 0) return -1; - if (ret > 0) { - ptr = info->scratch; - bs = ret; - fi->blocksizes[idx] = bs; + if (ret > 0 && (size_t)ret < size) { + size = ret; + ret = write_retry(info->outfd, info->scratch, size); + *outsize = size; } else { - ptr = info->block; - fi->blocksizes[idx] = bs | (1 << 24); + ret = write_retry(info->outfd, in, size); + *outsize = size | (1 << 24); } - ret = write_retry(info->outfd, ptr, bs); if (ret < 0) { perror("writing to output file"); return -1; } - if ((size_t)ret < bs) { + if ((size_t)ret < size) { fputs("write to output file truncated\n", stderr); return -1; } - info->super.bytes_used += bs; + info->super.bytes_used += ret; return 0; } -static int flush_fragments(sqfs_info_t *info) +static int grow_fragment_table(sqfs_info_t *info) { - size_t newsz, size; - uint64_t offset; - void *new, *ptr; - ssize_t ret; + size_t newsz; + void *new; if (info->num_fragments == info->max_fragments) { newsz = info->max_fragments ? info->max_fragments * 2 : 16; @@ -61,43 +54,27 @@ static int flush_fragments(sqfs_info_t *info) info->fragments = new; } + return 0; +} + +static int flush_fragments(sqfs_info_t *info) +{ + uint64_t offset; + uint32_t out; + + if (grow_fragment_table(info)) + return -1; + offset = info->super.bytes_used; - size = info->frag_offset; - ret = info->cmp->do_block(info->cmp, info->fragment, size, - info->scratch, info->super.block_size); - if (ret < 0) + if (write_compressed(info, info->fragment, info->frag_offset, &out)) return -1; info->fragments[info->num_fragments].start_offset = htole64(offset); info->fragments[info->num_fragments].pad0 = 0; - - if (ret > 0) { - ptr = info->scratch; - size = ret; - info->fragments[info->num_fragments].size = htole32(size); - } else { - ptr = info->fragment; - info->fragments[info->num_fragments].size = - htole32(size | (1 << 24)); - } + info->fragments[info->num_fragments].size = htole32(out); info->num_fragments += 1; - - ret = write_retry(info->outfd, ptr, size); - if (ret < 0) { - perror("writing to output file"); - return -1; - } - - if ((size_t)ret < size) { - fputs("write to output file truncated\n", stderr); - return -1; - } - - memset(info->fragment, 0, info->super.block_size); - - info->super.bytes_used += size; info->frag_offset = 0; info->super.flags &= ~SQFS_FLAG_NO_FRAGMENTS; @@ -105,25 +82,11 @@ static int flush_fragments(sqfs_info_t *info) return 0; } -static int add_fragment(file_info_t *fi, sqfs_info_t *info, size_t size) -{ - if (info->frag_offset + size > info->super.block_size) { - if (flush_fragments(info)) - return -1; - } - - fi->fragment_offset = info->frag_offset; - fi->fragment = info->num_fragments; - - memcpy((char *)info->fragment + info->frag_offset, info->block, size); - info->frag_offset += size; - return 0; -} - static int process_file(sqfs_info_t *info, file_info_t *fi) { + int infd, ret, blk_idx = 0; uint64_t count = fi->size; - int infd, ret; + uint32_t out; size_t diff; infd = open(fi->input_file, O_RDONLY); @@ -133,7 +96,6 @@ static int process_file(sqfs_info_t *info, file_info_t *fi) } fi->startblock = info->super.bytes_used; - info->file_block_count = 0; while (count != 0) { diff = count > (uint64_t)info->super.block_size ? @@ -146,11 +108,24 @@ static int process_file(sqfs_info_t *info, file_info_t *fi) goto fail_trunc; if (diff < info->super.block_size) { - if (add_fragment(fi, info, diff)) - goto fail; + if (info->frag_offset + diff > info->super.block_size) { + if (flush_fragments(info)) + goto fail; + } + + fi->fragment_offset = info->frag_offset; + fi->fragment = info->num_fragments; + + memcpy((char *)info->fragment + info->frag_offset, + info->block, diff); + info->frag_offset += diff; } else { - if (write_block(fi, info)) + if (write_compressed(info, info->block, + info->super.block_size, &out)) { goto fail; + } + + fi->blocksizes[blk_idx++] = out; } count -= diff; diff --git a/mkfs/mkfs.h b/mkfs/mkfs.h index c4cd8a1..fe4123b 100644 --- a/mkfs/mkfs.h +++ b/mkfs/mkfs.h @@ -47,8 +47,6 @@ typedef struct { sqfs_fragment_t *fragments; size_t num_fragments; size_t max_fragments; - - int file_block_count; size_t frag_offset; id_table_t idtbl; -- cgit v1.2.3