From e0e98b7b747f63c1b8fccd035592e3684fdb2691 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Wed, 25 Sep 2019 13:21:07 +0200 Subject: Add the ability to hook into the data writer block writing Signed-off-by: David Oberhollenzer --- include/sqfs/data_writer.h | 98 +++++++++++++++++++++++++++++++++++++++++ include/sqfs/predef.h | 1 + lib/sqfs/data_writer/block.c | 39 +++++++++++----- lib/sqfs/data_writer/common.c | 7 +++ lib/sqfs/data_writer/fragment.c | 21 ++++++--- lib/sqfs/data_writer/internal.h | 3 ++ 6 files changed, 152 insertions(+), 17 deletions(-) diff --git a/include/sqfs/data_writer.h b/include/sqfs/data_writer.h index 3f1ad02..cc99700 100644 --- a/include/sqfs/data_writer.h +++ b/include/sqfs/data_writer.h @@ -42,6 +42,91 @@ * is called for each one. */ +/** + * @struct sqfs_block_hooks_t + * + * @brief A set of hooks for tapping into the data writer. + * + * This structure can be registered with an @ref sqfs_data_writer_t and + * contains function pointers that will be called during various stages + * when writing data to disk. + * + * The callbacks can not only be used for accounting but may also write extra + * data to the output file or make modifications to the blocks before they are + * writtien. + * + * The callbacks can be individually set to NULL to disable them. + */ +struct sqfs_block_hooks_t { + /** + * @brief Gets called before writing a block to disk. + * + * If this is not NULL, it gets called before a block is written to + * disk. If the block has the @ref SQFS_BLK_ALLIGN flag set, the + * function is called before padding the file. + * + * The function may modify the block itself or write data to the file. + * which is taken into account when padding the file. + * + * @param user A user pointer. + * @param block The block that is about to be written. + * @param file The file that the block will be written to. + */ + void (*pre_block_write)(void *user, sqfs_block_t *block, + sqfs_file_t *file); + + /** + * @brief Gets called after writing a block to disk. + * + * If this is not NULL, it gets called after a block is written to + * disk. If the block has the @ref SQFS_BLK_ALLIGN flag set, the + * function is called before padding the file. + * + * Modifying the block is rather pointless, but the function may + * write data to the file which is taken into account when padding + * the file. + * + * @param user A user pointer. + * @param block The block that is about to be written. + * @param file The file that the block was written to. + */ + void (*post_block_write)(void *user, const sqfs_block_t *block, + sqfs_file_t *file); + + /** + * @brief Gets called before storing a fragment in a fragment block. + * + * The function can modify the block before it is stored. + * + * @param user A user pointer. + * @param block The data chunk that is about to be merged into the + * fragment block. + */ + void (*pre_fragment_store)(void *user, sqfs_block_t *block); + + /** + * @brief Gets called if block deduplication managed to get + * rid of the data blocks of a file. + * + * @param user A user pointer. + * @param count The number of blocks that have been erased. + * @param bytes The number of bytes that have been erased. Includes + * potential padding before and after the end. + */ + void (*notify_blocks_erased)(void *user, size_t count, + uint64_t bytes); + + /** + * @brief Gets called before throwing away a fragment that turned out + * to be a duplicate. + * + * @param user A user pointer. + * @param block The data chunk that is about to be merged into the + * fragment block. + */ + void (*notify_fragment_discard)(void *user, const sqfs_block_t *block); +}; + #ifdef __cplusplus extern "C" { #endif @@ -134,6 +219,19 @@ SQFS_API int sqfs_data_writer_write_fragment_table(sqfs_data_writer_t *proc, sqfs_super_t *super); +/** + * @brief Register a set of hooks to be invoked when writing blocks to disk. + * + * @memberof sqfs_data_writer_t + * + * @param proc A pointer to a data writer object. + * @param user_ptr A user pointer to pass to the callbacks. + * @param hooks A structure containing the hooks. + */ +SQFS_API +void sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr, + const sqfs_block_hooks_t *hooks); + #ifdef __cplusplus } #endif diff --git a/include/sqfs/predef.h b/include/sqfs/predef.h index c94ca29..8a554dd 100644 --- a/include/sqfs/predef.h +++ b/include/sqfs/predef.h @@ -72,6 +72,7 @@ typedef struct sqfs_file_t sqfs_file_t; typedef struct sqfs_sparse_map_t sqfs_sparse_map_t; typedef struct sqfs_tree_node_t sqfs_tree_node_t; typedef struct sqfs_data_reader_t sqfs_data_reader_t; +typedef struct sqfs_block_hooks_t sqfs_block_hooks_t; typedef struct sqfs_fragment_t sqfs_fragment_t; typedef struct sqfs_dir_header_t sqfs_dir_header_t; diff --git a/lib/sqfs/data_writer/block.c b/lib/sqfs/data_writer/block.c index 9461737..9c40793 100644 --- a/lib/sqfs/data_writer/block.c +++ b/lib/sqfs/data_writer/block.c @@ -61,11 +61,15 @@ static int allign_file(sqfs_data_writer_t *proc, sqfs_block_t *blk) int process_completed_block(sqfs_data_writer_t *proc, sqfs_block_t *blk) { + uint64_t offset, bytes; size_t start, count; - uint64_t offset; uint32_t out; int err; + if (proc->hooks != NULL && proc->hooks->pre_block_write != NULL) { + proc->hooks->pre_block_write(proc->user_ptr, blk, proc->file); + } + if (blk->flags & SQFS_BLK_FIRST_BLOCK) { proc->start = proc->file->get_size(proc->file); proc->file_start = proc->num_blocks; @@ -101,6 +105,10 @@ int process_completed_block(sqfs_data_writer_t *proc, sqfs_block_t *blk) return err; } + if (proc->hooks != NULL && proc->hooks->post_block_write != NULL) { + proc->hooks->post_block_write(proc->user_ptr, blk, proc->file); + } + if (blk->flags & SQFS_BLK_LAST_BLOCK) { err = allign_file(proc, blk); if (err) @@ -112,19 +120,28 @@ int process_completed_block(sqfs_data_writer_t *proc, sqfs_block_t *blk) sqfs_inode_set_file_block_start(blk->inode, offset); - if (start < proc->file_start) { - offset = start + count; + if (start >= proc->file_start) + return 0; + + offset = start + count; + if (offset >= proc->file_start) { + count = proc->num_blocks - offset; + proc->num_blocks = offset; + } else { + proc->num_blocks = proc->file_start; + } - if (offset >= proc->file_start) { - proc->num_blocks = offset; - } else { - proc->num_blocks = proc->file_start; - } + if (proc->hooks != NULL && + proc->hooks->notify_blocks_erased != NULL) { + bytes = proc->file->get_size(proc->file) - proc->start; - err = proc->file->truncate(proc->file, proc->start); - if (err) - return err; + proc->hooks->notify_blocks_erased(proc->user_ptr, + count, bytes); } + + err = proc->file->truncate(proc->file, proc->start); + if (err) + return err; } return 0; diff --git a/lib/sqfs/data_writer/common.c b/lib/sqfs/data_writer/common.c index 51acc1e..c9d5589 100644 --- a/lib/sqfs/data_writer/common.c +++ b/lib/sqfs/data_writer/common.c @@ -155,3 +155,10 @@ int sqfs_data_writer_write_fragment_table(sqfs_data_writer_t *proc, super->fragment_table_start = start; return 0; } + +void sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr, + const sqfs_block_hooks_t *hooks) +{ + proc->hooks = hooks; + proc->user_ptr = user_ptr; +} diff --git a/lib/sqfs/data_writer/fragment.c b/lib/sqfs/data_writer/fragment.c index e4fe9b4..9f169b7 100644 --- a/lib/sqfs/data_writer/fragment.c +++ b/lib/sqfs/data_writer/fragment.c @@ -64,6 +64,10 @@ static int store_fragment(sqfs_data_writer_t *proc, sqfs_block_t *frag, sqfs_inode_set_frag_location(frag->inode, proc->frag_block->index, proc->frag_block->size); + if (proc->hooks != NULL && proc->hooks->pre_fragment_store != NULL) { + proc->hooks->pre_fragment_store(proc->user_ptr, frag); + } + memcpy(proc->frag_block->data + proc->frag_block->size, frag->data, frag->size); @@ -82,12 +86,8 @@ int process_completed_fragment(sqfs_data_writer_t *proc, sqfs_block_t *frag, hash = MK_BLK_HASH(frag->checksum, frag->size); for (i = 0; i < proc->frag_list_num; ++i) { - if (proc->frag_list[i].hash == hash) { - sqfs_inode_set_frag_location(frag->inode, - proc->frag_list[i].index, - proc->frag_list[i].offset); - return 0; - } + if (proc->frag_list[i].hash == hash) + goto out_duplicate; } if (proc->frag_block != NULL) { @@ -125,4 +125,13 @@ fail: free(*blk_out); *blk_out = NULL; return err; +out_duplicate: + sqfs_inode_set_frag_location(frag->inode, proc->frag_list[i].index, + proc->frag_list[i].offset); + + if (proc->hooks != NULL && + proc->hooks->notify_fragment_discard != NULL) { + proc->hooks->notify_fragment_discard(proc->user_ptr, frag); + } + return 0; } diff --git a/lib/sqfs/data_writer/internal.h b/lib/sqfs/data_writer/internal.h index 69de9ac..53ddc5f 100644 --- a/lib/sqfs/data_writer/internal.h +++ b/lib/sqfs/data_writer/internal.h @@ -98,6 +98,9 @@ struct sqfs_data_writer_t { size_t frag_list_num; size_t frag_list_max; + const sqfs_block_hooks_t *hooks; + void *user_ptr; + /* used only by workers */ size_t max_block_size; -- cgit v1.2.3