Move super block init/write code to libsquashfs.a

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 96 insertions, 1 deletions

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index c969eff..86f1766 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -7,7 +7,7 @@ libcompress_a_CFLAGS = $(AM_CFLAGS)
 libcompress_a_CPPFLAGS = $(AM_CPPFLAGS)
 
 libsquashfs_a_SOURCES = include/meta_writer.h include/squashfs.h
-libsquashfs_a_SOURCES += lib/sqfs/meta_writer.c
+libsquashfs_a_SOURCES += lib/sqfs/meta_writer.c lib/sqfs/super.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/super.c b/lib/sqfs/super.c
new file mode 100644
index 0000000..b402496
--- /dev/null
+++ b/lib/sqfs/super.c
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "squashfs.h"
+#include "util.h"
+
+#include <endian.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+
+int sqfs_super_init(sqfs_super_t *super, size_t block_size, uint32_t mtime,
+		    E_SQFS_COMPRESSOR compressor)
+{
+	unsigned int i;
+
+	if (block_size & (block_size - 1)) {
+		fputs("Block size must be a power of 2!\n", stderr);
+		return -1;
+	}
+
+	if (block_size < 8192 || block_size >= (1 << 24)) {
+		fputs("Block size must be between 8k and 1M\n", stderr);
+		return -1;
+	}
+
+	memset(super, 0, sizeof(*super));
+	super->magic = SQFS_MAGIC;
+	super->modification_time = mtime;
+	super->block_size = block_size;
+	super->compression_id = compressor;
+	super->flags = SQFS_FLAG_NO_FRAGMENTS | SQFS_FLAG_NO_XATTRS;
+	super->version_major = SQFS_VERSION_MAJOR;
+	super->version_minor = SQFS_VERSION_MINOR;
+	super->bytes_used = sizeof(*super);
+	super->id_table_start = 0xFFFFFFFFFFFFFFFFUL;
+	super->xattr_id_table_start = 0xFFFFFFFFFFFFFFFFUL;
+	super->inode_table_start = 0xFFFFFFFFFFFFFFFFUL;
+	super->directory_table_start = 0xFFFFFFFFFFFFFFFFUL;
+	super->fragment_table_start = 0xFFFFFFFFFFFFFFFFUL;
+	super->export_table_start = 0xFFFFFFFFFFFFFFFFUL;
+
+	for (i = block_size; i != 0x01; i >>= 1)
+		super->block_log += 1;
+
+	return 0;
+}
+
+int sqfs_super_write(sqfs_super_t *super, int fd)
+{
+	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(fd, 0, SEEK_SET) == (off_t)-1)
+		goto fail_seek;
+
+	ret = write_retry(fd, &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(fd, 0, SEEK_END) == (off_t)-1)
+		goto fail_seek;
+
+	return 0;
+fail_seek:
+	perror("squashfs writing super block: seek on output file");
+	return -1;
+}