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-rw-r--r--mkfs/super.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/mkfs/super.c b/mkfs/super.c
new file mode 100644
index 0000000..b3755d1
--- /dev/null
+++ b/mkfs/super.c
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "mksquashfs.h"
+#include "util.h"
+
+#include <endian.h>
+
+int sqfs_super_init(sqfs_super_t *s, const options_t *opt)
+{
+ unsigned int i;
+
+ if (opt->blksz & (opt->blksz - 1)) {
+ fputs("Block size must be a power of 2!\n", stderr);
+ return -1;
+ }
+
+ if (opt->blksz < 8192 || opt->blksz >= (1 << 24)) {
+ fputs("Block size must be between 8k and 1M\n", stderr);
+ return -1;
+ }
+
+ memset(s, 0, sizeof(*s));
+ s->magic = SQFS_MAGIC;
+ s->modification_time = opt->def_mtime;
+ s->block_size = opt->blksz;
+ s->compression_id = opt->compressor;
+ s->flags = SQFS_FLAG_NO_FRAGMENTS | SQFS_FLAG_NO_XATTRS;
+ s->version_major = SQFS_VERSION_MAJOR;
+ s->version_minor = SQFS_VERSION_MINOR;
+ s->bytes_used = sizeof(*s);
+ s->id_table_start = 0xFFFFFFFFFFFFFFFFUL;
+ s->xattr_id_table_start = 0xFFFFFFFFFFFFFFFFUL;
+ s->inode_table_start = 0xFFFFFFFFFFFFFFFFUL;
+ s->directory_table_start = 0xFFFFFFFFFFFFFFFFUL;
+ s->fragment_table_start = 0xFFFFFFFFFFFFFFFFUL;
+ s->export_table_start = 0xFFFFFFFFFFFFFFFFUL;
+
+ for (i = opt->blksz; i != 0x01; i >>= 1)
+ s->block_log += 1;
+
+ return 0;
+}
+
+int sqfs_padd_file(sqfs_super_t *s, const options_t *opt, int outfd)
+{
+ size_t padd_sz = s->bytes_used % opt->devblksz;
+ uint8_t *buffer;
+ ssize_t ret;
+
+ if (padd_sz == 0)
+ return 0;
+
+ padd_sz = opt->devblksz - padd_sz;
+
+ buffer = calloc(1, padd_sz);
+ if (buffer == NULL) {
+ perror("padding output file to block size");
+ return -1;
+ }
+
+ ret = write_retry(outfd, buffer, padd_sz);
+
+ if (ret < 0) {
+ perror("Error padding squashfs image to page size");
+ free(buffer);
+ return -1;
+ }
+
+ if ((size_t)ret < padd_sz) {
+ fputs("Truncated write trying to padd squashfs image\n",
+ stderr);
+ return -1;
+ }
+
+ free(buffer);
+ return 0;
+}
+
+int sqfs_super_write(const sqfs_super_t *super, int outfd)
+{
+ sqfs_super_t copy;
+ ssize_t ret;
+
+ copy.magic = htole32(super->magic);
+ copy.inode_count = htole32(super->inode_count);
+ copy.modification_time = htole32(super->modification_time);
+ copy.block_size = htole32(super->block_size);
+ copy.fragment_entry_count = htole32(super->fragment_entry_count);
+ copy.compression_id = htole16(super->compression_id);
+ copy.block_log = htole16(super->block_log);
+ copy.flags = htole16(super->flags);
+ copy.id_count = htole16(super->id_count);
+ copy.version_major = htole16(super->version_major);
+ copy.version_minor = htole16(super->version_minor);
+ copy.root_inode_ref = htole64(super->root_inode_ref);
+ copy.bytes_used = htole64(super->bytes_used);
+ copy.id_table_start = htole64(super->id_table_start);
+ copy.xattr_id_table_start = htole64(super->xattr_id_table_start);
+ copy.inode_table_start = htole64(super->inode_table_start);
+ copy.directory_table_start = htole64(super->directory_table_start);
+ copy.fragment_table_start = htole64(super->fragment_table_start);
+ copy.export_table_start = htole64(super->export_table_start);
+
+ if (lseek(outfd, 0, SEEK_SET) == (off_t)-1)
+ goto fail_seek;
+
+ ret = write_retry(outfd, &copy, sizeof(copy));
+
+ if (ret < 0) {
+ perror("squashfs writing super block");
+ return -1;
+ }
+
+ if ((size_t)ret < sizeof(copy)) {
+ fputs("squashfs writing super block: truncated write\n",
+ stderr);
+ return -1;
+ }
+
+ if (lseek(outfd, 0, SEEK_END) == (off_t)-1)
+ goto fail_seek;
+
+ return 0;
+fail_seek:
+ perror("squashfs writing super block: seek on output file");
+ return -1;
+}