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Diffstat (limited to 'lib/sqfs/id_table_read.c')
-rw-r--r--lib/sqfs/id_table_read.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/lib/sqfs/id_table_read.c b/lib/sqfs/id_table_read.c
new file mode 100644
index 0000000..b1305ff
--- /dev/null
+++ b/lib/sqfs/id_table_read.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "meta_reader.h"
+#include "id_table.h"
+#include "table.h"
+#include "util.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+int id_table_read(id_table_t *tbl, int fd, sqfs_super_t *super,
+ compressor_t *cmp)
+{
+ size_t i, block_count, count, diff;
+ uint64_t blocks[32];
+ meta_reader_t *m;
+ uint32_t *ptr;
+ ssize_t ret;
+
+ if (tbl->ids != NULL) {
+ free(tbl->ids);
+ tbl->num_ids = 0;
+ tbl->max_ids = 0;
+ tbl->ids = NULL;
+ }
+
+ if (!super->id_count || super->id_table_start >= super->bytes_used) {
+ fputs("ID table missing from file system\n", stderr);
+ return -1;
+ }
+
+ tbl->ids = malloc(super->id_count * sizeof(uint32_t));
+ if (tbl->ids == NULL) {
+ perror("reading ID table");
+ return -1;
+ }
+
+ tbl->num_ids = super->id_count;
+ tbl->max_ids = super->id_count;
+
+ if (lseek(fd, super->id_table_start, SEEK_SET) == (off_t)-1)
+ goto fail_seek;
+
+ block_count = super->id_count / 2048;
+ if (super->id_count % 2048)
+ ++block_count;
+
+ ret = read_retry(fd, blocks, sizeof(blocks[0]) * block_count);
+ if (ret < 0)
+ goto fail_rd;
+
+ if ((size_t)ret < sizeof(blocks[0]) * block_count)
+ goto fail_trunc;
+
+ for (i = 0; i < block_count; ++i)
+ blocks[i] = le64toh(blocks[i]);
+
+ m = meta_reader_create(fd, cmp);
+ if (m == NULL)
+ return -1;
+
+ count = super->id_count;
+ ptr = tbl->ids;
+
+ for (i = 0; i < block_count && count > 0; ++i) {
+ diff = count < 2048 ? count : 2048;
+
+ if (meta_reader_seek(m, blocks[i], 0))
+ goto fail_meta;
+
+ if (meta_reader_read(m, ptr, diff * sizeof(tbl->ids[0])))
+ goto fail_meta;
+
+ count -= diff;
+ ptr += diff;
+ }
+
+ meta_reader_destroy(m);
+
+ for (i = 0; i < tbl->num_ids; ++i)
+ tbl->ids[i] = le32toh(tbl->ids[i]);
+
+ return 0;
+fail_meta:
+ meta_reader_destroy(m);
+ return -1;
+fail_trunc:
+ fputs("reading ID table: unexpected end of file\n", stderr);
+ return -1;
+fail_rd:
+ perror("reading ID table");
+ return -1;
+fail_seek:
+ perror("seeking to ID table");
+ return -1;
+}