diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Makemodule.am | 4 | ||||
| -rw-r--r-- | lib/sqfs/data_reader.c | 157 |
2 files changed, 159 insertions, 2 deletions
diff --git a/lib/Makemodule.am b/lib/Makemodule.am index 3c1ef12..ddc78f6 100644 --- a/lib/Makemodule.am +++ b/lib/Makemodule.am @@ -23,8 +23,8 @@ libsquashfs_a_SOURCES += lib/sqfs/serialize_fstree.c libsquashfs_a_SOURCES += lib/sqfs/tree_node_from_inode.c libsquashfs_a_SOURCES += lib/sqfs/deserialize_fstree.c libsquashfs_a_SOURCES += lib/sqfs/data_writer.c lib/sqfs/write_xattr.c -libsquashfs_a_SOURCES += include/data_writer.h -libsquashfs_a_SOURCES += include/frag_reader.h +libsquashfs_a_SOURCES += include/data_writer.h include/frag_reader.h +libsquashfs_a_SOURCES += include/data_reader.h lib/sqfs/data_reader.c libutil_a_SOURCES = lib/util/canonicalize_name.c lib/util/write_retry.c libutil_a_SOURCES += lib/util/read_retry.c include/util.h diff --git a/lib/sqfs/data_reader.c b/lib/sqfs/data_reader.c new file mode 100644 index 0000000..22413f2 --- /dev/null +++ b/lib/sqfs/data_reader.c @@ -0,0 +1,157 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +#include "data_reader.h" +#include "frag_reader.h" +#include "util.h" + +#include <stdlib.h> +#include <unistd.h> +#include <stdio.h> + +struct data_reader_t { + compressor_t *cmp; + size_t block_size; + frag_reader_t *frag; + int sqfsfd; + + void *buffer; + void *scratch; +}; + +data_reader_t *data_reader_create(int fd, sqfs_super_t *super, + compressor_t *cmp) +{ + data_reader_t *data = calloc(1, sizeof(*data) + 2 * super->block_size); + + if (data == NULL) { + perror("creating data reader"); + return data; + } + + if (super->fragment_entry_count > 0 && + !(super->flags & SQFS_FLAG_NO_FRAGMENTS)) { + if (super->fragment_table_start >= super->bytes_used) { + fputs("Fragment table start is past end of file\n", + stderr); + free(data); + return NULL; + } + + data->frag = frag_reader_create(super, fd, cmp); + if (data->frag == NULL) { + free(data); + return NULL; + } + } + + data->buffer = (char *)data + sizeof(*data); + data->scratch = (char *)data->buffer + super->block_size; + data->sqfsfd = fd; + data->block_size = super->block_size; + data->cmp = cmp; + return data; +} + +void data_reader_destroy(data_reader_t *data) +{ + if (data->frag != NULL) + frag_reader_destroy(data->frag); + free(data); +} + +int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd) +{ + size_t i, count, fragsz; + bool compressed; + uint32_t bs; + ssize_t ret; + void *ptr; + + count = fi->size / data->block_size; + + if (count > 0) { + if (lseek(data->sqfsfd, fi->startblock, SEEK_SET) == (off_t)-1) + goto fail_seek; + + for (i = 0; i < count; ++i) { + bs = fi->blocksizes[i]; + + compressed = (bs & (1 << 24)) == 0; + bs &= (1 << 24) - 1; + + if (bs > data->block_size) + goto fail_bs; + + ret = read_retry(data->sqfsfd, data->buffer, bs); + if (ret < 0) + goto fail_rd; + + if ((size_t)ret < bs) + goto fail_trunc; + + if (compressed) { + ret = data->cmp->do_block(data->cmp, + data->buffer, bs, + data->scratch, + data->block_size); + if (ret <= 0) + return -1; + + bs = ret; + ptr = data->scratch; + } else { + ptr = data->buffer; + } + + ret = write_retry(outfd, ptr, bs); + if (ret < 0) + goto fail_wr; + + if ((size_t)ret < bs) + goto fail_wr_trunc; + } + } + + fragsz = fi->size % data->block_size; + + if (fragsz > 0) { + if (data->frag == NULL) + goto fail_frag; + + if (frag_reader_read(data->frag, fi->fragment, + fi->fragment_offset, data->buffer, + fragsz)) { + return -1; + } + + ret = write_retry(outfd, data->buffer, fragsz); + if (ret < 0) + goto fail_wr; + + if ((size_t)ret < fragsz) + goto fail_wr_trunc; + } + + return 0; +fail_seek: + perror("seek on squashfs"); + return -1; +fail_wr: + perror("writing uncompressed block"); + return -1; +fail_wr_trunc: + fputs("writing uncompressed block: truncated write\n", stderr); + return -1; +fail_rd: + perror("reading from squashfs"); + return -1; +fail_trunc: + fputs("reading from squashfs: unexpected end of file\n", stderr); + return -1; +fail_bs: + fputs("found compressed block larger than block size\n", stderr); + return -1; +fail_frag: + fputs("file not a multiple of block size but no fragments available\n", + stderr); + return -1; +} |