Add super block and padding functions

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

4 files changed, 180 insertions, 18 deletions

diff --git a/mkfs/Makemodule.am b/mkfs/Makemodule.am
index 7b0b353..1f0acf2 100644
--- a/mkfs/Makemodule.am
+++ b/mkfs/Makemodule.am
@@ -1,5 +1,7 @@
-mksquashfs_SOURCES = mkfs/mksquashfs.c mkfs/options.c mkfs/options.h
+mksquashfs_SOURCES = mkfs/mksquashfs.c mkfs/mksquashfs.h
+mksquashfs_SOURCES += mkfs/options.c mkfs/options.h
 mksquashfs_SOURCES += mkfs/meta_writer.c mkfs/meta_writer.h
+mksquashfs_SOURCES += mkfs/super.c
 mksquashfs_SOURCES += include/squashfs.h
 mksquashfs_LDADD = libutil.a libfstree.a libcompress.a
 
diff --git a/mkfs/mksquashfs.c b/mkfs/mksquashfs.c
index bc2a215..17de4ed 100644
--- a/mkfs/mksquashfs.c
+++ b/mkfs/mksquashfs.c
@@ -1,14 +1,5 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
-#include "squashfs.h"
-#include "options.h"
-#include "fstree.h"
-
-#include <sys/sysmacros.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <stdio.h>
-#include <ctype.h>
+#include "mksquashfs.h"
 
 static void print_tree(int level, tree_node_t *node)
 {
@@ -43,28 +34,49 @@ static void print_tree(int level, tree_node_t *node)
 	}
 }
 
-
 int main(int argc, char **argv)
 {
+	int outfd, status = EXIT_FAILURE;
+	sqfs_super_t super;
 	options_t opt;
 	fstree_t fs;
 
 	process_command_line(&opt, argc, argv);
 
-	if (fstree_init(&fs, opt.blksz, opt.def_mtime, opt.def_mode,
-			opt.def_uid, opt.def_gid)) {
+	if (sqfs_super_init(&super, &opt) != 0)
 		return EXIT_FAILURE;
-	}
 
-	if (fstree_from_file(&fs, opt.infile)) {
-		fstree_cleanup(&fs);
+	outfd = open(opt.outfile, opt.outmode, 0644);
+	if (outfd < 0) {
+		perror(opt.outfile);
 		return EXIT_FAILURE;
 	}
 
+	if (sqfs_super_write(&super, outfd))
+		goto out_outfd;
+
+	if (fstree_init(&fs, opt.blksz, opt.def_mtime, opt.def_mode,
+			opt.def_uid, opt.def_gid)) {
+		goto out_outfd;
+	}
+
+	if (fstree_from_file(&fs, opt.infile))
+		goto out_fstree;
+
 	fstree_sort(&fs);
 
 	print_tree(0, fs.root);
 
+	if (sqfs_super_write(&super, outfd))
+		goto out_outfd;
+
+	if (sqfs_padd_file(&super, &opt, outfd))
+		goto out_fstree;
+
+	status = EXIT_SUCCESS;
+out_fstree:
 	fstree_cleanup(&fs);
-	return EXIT_SUCCESS;
+out_outfd:
+	close(outfd);
+	return status;
 }
diff --git a/mkfs/mksquashfs.h b/mkfs/mksquashfs.h
new file mode 100644
index 0000000..8dda29c
--- /dev/null
+++ b/mkfs/mksquashfs.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#ifndef MKSQUASHFS_H
+#define MKSQUASHFS_H
+
+#include "squashfs.h"
+#include "options.h"
+#include "fstree.h"
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int sqfs_super_init(sqfs_super_t *s, const options_t *opt);
+
+int sqfs_padd_file(sqfs_super_t *s, const options_t *opt, int outfd);
+
+int sqfs_super_write(const sqfs_super_t *super, int outfd);
+
+#endif /* MKSQUASHFS_H */
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;
+}