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-rw-r--r--include/squashfs.h4
-rw-r--r--lib/sqfs/data_reader.c231
2 files changed, 112 insertions, 123 deletions
diff --git a/include/squashfs.h b/include/squashfs.h
index fb60049..eb35fdd 100644
--- a/include/squashfs.h
+++ b/include/squashfs.h
@@ -21,6 +21,10 @@
#define SQFS_DEVBLK_SIZE 4096
#define SQFS_MAX_DIR_ENT 256
+#define SQFS_IS_BLOCK_COMPRESSED(size) (((size) & (1 << 24)) == 0)
+#define SQFS_ON_DISK_BLOCK_SIZE(size) ((size) & ((1 << 24) - 1))
+#define SQFS_IS_SPARSE_BLOCK(size) (SQFS_ON_DISK_BLOCK_SIZE(size) == 0)
+
typedef struct {
uint32_t magic;
uint32_t inode_count;
diff --git a/lib/sqfs/data_reader.c b/lib/sqfs/data_reader.c
index cdb806c..2b111db 100644
--- a/lib/sqfs/data_reader.c
+++ b/lib/sqfs/data_reader.c
@@ -21,15 +21,89 @@ struct data_reader_t {
size_t current_frag_index;
size_t frag_used;
+ off_t current_block;
+
compressor_t *cmp;
size_t block_size;
int sqfsfd;
- void *buffer;
+ void *block;
void *scratch;
void *frag_block;
};
+static ssize_t read_block(data_reader_t *data, off_t offset, uint32_t size,
+ void *dst)
+{
+ bool compressed = SQFS_IS_BLOCK_COMPRESSED(size);
+ void *ptr = compressed ? data->scratch : dst;
+ ssize_t ret;
+
+ size = SQFS_ON_DISK_BLOCK_SIZE(size);
+
+ if (size > data->block_size)
+ goto fail_bs;
+
+ if (read_data_at("reading block", offset, data->sqfsfd, ptr, size))
+ return -1;
+
+ if (compressed) {
+ ret = data->cmp->do_block(data->cmp, data->scratch, size,
+ dst, data->block_size);
+ if (ret <= 0) {
+ fputs("extracting block failed\n", stderr);
+ return -1;
+ }
+ size = ret;
+ }
+
+ return size;
+fail_bs:
+ fputs("found compressed block larger than block size\n", stderr);
+ return -1;
+}
+
+static int precache_data_block(data_reader_t *data, off_t location,
+ uint32_t size)
+{
+ ssize_t ret;
+
+ if (data->current_block == location)
+ return 0;
+
+ ret = read_block(data, location, size, data->block);
+ if (ret < 0)
+ return -1;
+
+ if (size < data->block_size)
+ memset((char *)data->block + size, 0, data->block_size - size);
+
+ data->current_block = location;
+ return 0;
+}
+
+static int precache_fragment_block(data_reader_t *data, size_t idx)
+{
+ ssize_t ret;
+
+ if (idx == data->current_frag_index)
+ return 0;
+
+ if (idx >= data->num_fragments) {
+ fputs("fragment index out of bounds\n", stderr);
+ return -1;
+ }
+
+ ret = read_block(data, data->frag[idx].start_offset,
+ data->frag[idx].size, data->frag_block);
+ if (ret < 0)
+ return -1;
+
+ data->current_frag_index = idx;
+ data->frag_used = ret;
+ return 0;
+}
+
data_reader_t *data_reader_create(int fd, sqfs_super_t *super,
compressor_t *cmp)
{
@@ -43,9 +117,10 @@ data_reader_t *data_reader_create(int fd, sqfs_super_t *super,
data->num_fragments = super->fragment_entry_count;
data->current_frag_index = super->fragment_entry_count;
- data->buffer = (char *)data + sizeof(*data);
- data->scratch = (char *)data->buffer + super->block_size;
+ data->block = (char *)data + sizeof(*data);
+ data->scratch = (char *)data->block + super->block_size;
data->frag_block = (char *)data->scratch + super->block_size;
+ data->current_block = -1;
data->sqfsfd = fd;
data->block_size = super->block_size;
data->cmp = cmp;
@@ -85,138 +160,45 @@ void data_reader_destroy(data_reader_t *data)
free(data);
}
-static int dump_blocks(data_reader_t *data, file_info_t *fi, int outfd,
- bool allow_sparse, size_t count)
+int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
+ bool allow_sparse)
{
- off_t sqfs_location = fi->startblock;
- size_t i, unpackedsz;
- uint64_t filesz = 0;
- bool compressed;
- uint32_t bs;
- ssize_t ret;
- void *ptr;
-
- for (i = 0; i < count; ++i) {
- bs = fi->blocks[i].size;
-
- compressed = (bs & (1 << 24)) == 0;
- bs &= (1 << 24) - 1;
-
- if (bs > data->block_size)
- goto fail_bs;
-
- if ((fi->size - filesz) < (uint64_t)data->block_size) {
- unpackedsz = fi->size - filesz;
- } else {
- unpackedsz = data->block_size;
- }
+ uint64_t filesz = fi->size;
+ size_t fragsz = fi->size % data->block_size;
+ size_t count = fi->size / data->block_size;
+ off_t off = fi->startblock;
+ size_t i, diff;
- filesz += unpackedsz;
+ if (fragsz != 0 && !(fi->flags & FILE_FLAG_HAS_FRAGMENT)) {
+ fragsz = 0;
+ ++count;
+ }
- if (bs == 0 && allow_sparse) {
- if (ftruncate(outfd, filesz))
- goto fail_sparse;
- if (lseek(outfd, 0, SEEK_END) == (off_t)-1)
- goto fail_sparse;
- continue;
- }
+ if (allow_sparse && ftruncate(outfd, filesz))
+ goto fail_sparse;
- if (bs == 0) {
- memset(data->buffer, 0, unpackedsz);
- compressed = false;
- } else {
- if (read_data_at("reading data block", sqfs_location,
- data->sqfsfd, data->buffer, bs)) {
- return -1;
+ for (i = 0; i < count; ++i) {
+ diff = filesz > data->block_size ? data->block_size : filesz;
+ filesz -= diff;
+
+ if (SQFS_IS_SPARSE_BLOCK(fi->blocks[i].size)) {
+ if (allow_sparse) {
+ if (lseek(outfd, diff, SEEK_CUR) == (off_t)-1)
+ goto fail_sparse;
+ } else {
+ memset(data->block, 0, diff);
}
- sqfs_location += bs;
- }
-
- if (compressed) {
- ret = data->cmp->do_block(data->cmp, data->buffer, bs,
- data->scratch,
- data->block_size);
- if (ret <= 0)
- return -1;
-
- ptr = data->scratch;
} else {
- ptr = data->buffer;
+ if (precache_data_block(data, off, fi->blocks[i].size))
+ return -1;
+ off += SQFS_ON_DISK_BLOCK_SIZE(fi->blocks[i].size);
}
if (write_data("writing uncompressed block",
- outfd, ptr, unpackedsz)) {
+ outfd, data->block, diff)) {
return -1;
}
}
- return 0;
-fail_sparse:
- perror("creating sparse output file");
- return -1;
-fail_bs:
- fputs("found compressed block larger than block size\n", stderr);
- return -1;
-}
-
-static int precache_fragment_block(data_reader_t *data, size_t idx)
-{
- bool compressed;
- size_t size;
- ssize_t ret;
-
- if (idx == data->current_frag_index)
- return 0;
-
- if (idx >= data->num_fragments) {
- fputs("fragment index out of bounds\n", stderr);
- return -1;
- }
-
- compressed = (data->frag[idx].size & (1 << 24)) == 0;
- size = data->frag[idx].size & ((1 << 24) - 1);
-
- if (size > data->block_size) {
- fputs("found fragment block larger than block size\n", stderr);
- return -1;
- }
-
- if (read_data_at("reading fragments", data->frag[idx].start_offset,
- data->sqfsfd, data->buffer, size)) {
- return -1;
- }
-
- if (compressed) {
- ret = data->cmp->do_block(data->cmp, data->buffer, size,
- data->frag_block, data->block_size);
-
- if (ret <= 0) {
- fputs("extracting fragment block failed\n", stderr);
- return -1;
- }
-
- size = ret;
- } else {
- memcpy(data->frag_block, data->buffer, size);
- }
-
- data->current_frag_index = idx;
- data->frag_used = size;
- return 0;
-}
-
-int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
- bool allow_sparse)
-{
- size_t fragsz = fi->size % data->block_size;
- size_t count = fi->size / data->block_size;
-
- if (fragsz != 0 && !(fi->flags & FILE_FLAG_HAS_FRAGMENT)) {
- fragsz = 0;
- ++count;
- }
-
- if (dump_blocks(data, fi, outfd, allow_sparse, count))
- return -1;
if (fragsz > 0) {
if (precache_fragment_block(data, fi->fragment))
@@ -239,4 +221,7 @@ int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
fail_range:
fputs("attempted to read past fragment block limits\n", stderr);
return -1;
+fail_sparse:
+ perror("creating sparse output file");
+ return -1;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 17:30:57 +0000