Implement 42.sqfs demo

A play on the famous 42.zip

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

2 files changed, 209 insertions, 1 deletions

diff --git a/extras/Makemodule.am b/extras/Makemodule.am
index 83d9e8b..77d734e 100644
--- a/extras/Makemodule.am
+++ b/extras/Makemodule.am
@@ -1,4 +1,7 @@
 mknastyfs_SOURCES = extras/mknastyfs.c
 mknastyfs_LDADD = libsquashfs.la
 
-noinst_PROGRAMS += mknastyfs
+mk42sqfs_SOURCES = extras/mk42sqfs.c
+mk42sqfs_LDADD = libsquashfs.la
+
+noinst_PROGRAMS += mknastyfs mk42sqfs
diff --git a/extras/mk42sqfs.c b/extras/mk42sqfs.c
new file mode 100644
index 0000000..25c9047
--- /dev/null
+++ b/extras/mk42sqfs.c
@@ -0,0 +1,205 @@
+#include "sqfs/meta_writer.h"
+#include "sqfs/dir_writer.h"
+#include "sqfs/compressor.h"
+#include "sqfs/id_table.h"
+#include "sqfs/inode.h"
+#include "sqfs/super.h"
+#include "sqfs/io.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+const char *README =
+"This SuqashFS image contains ITSELF 42 times. Do NOT try to recursively\n"
+"scan or unpack it. You will end up with an infinite amount of data!\n";
+
+static void add_padding(sqfs_file_t *file)
+{
+	sqfs_u64 diff, size;
+
+	size = file->get_size(file);
+	diff = size % 4096;
+
+	if (diff > 0)
+		file->truncate(file, size + (4096 - diff));
+}
+
+static sqfs_inode_generic_t *create_file_inode(sqfs_id_table_t *idtbl,
+					       unsigned int inode_num)
+{
+	sqfs_inode_generic_t *inode;
+
+	inode = calloc(1, sizeof(*inode) + sizeof(sqfs_u32));
+	inode->base.type = SQFS_INODE_FILE;
+	inode->base.mode = SQFS_INODE_MODE_REG | 0644;
+	inode->base.inode_number = inode_num;
+
+	sqfs_id_table_id_to_index(idtbl, 0, &inode->base.uid_idx);
+	sqfs_id_table_id_to_index(idtbl, 0, &inode->base.gid_idx);
+
+	inode->data.file.file_size = 4096;
+	inode->data.file.fragment_index = 0xFFFFFFFF;
+
+	inode->num_file_blocks = 1;
+	inode->block_sizes = (sqfs_u32 *)inode->extra;
+	inode->block_sizes[0] = (1 << 24) | inode->data.file.file_size;
+	return inode;
+}
+
+int main(void)
+{
+	sqfs_meta_writer_t *inode_m, *dir_m;
+	sqfs_compressor_config_t cfg;
+	sqfs_inode_generic_t *inode;
+	unsigned int i, inode_num;
+	int status = EXIT_FAILURE;
+	sqfs_dir_writer_t *dirwr;
+	sqfs_compressor_t *cmp;
+	sqfs_id_table_t *idtbl;
+	sqfs_u64 block_start;
+	sqfs_super_t super;
+	sqfs_file_t *file;
+	sqfs_u32 offset;
+	char buffer[32];
+
+	/* get a file object referring to our destination file */
+	file = sqfs_open_file("42.sqfs", SQFS_FILE_OPEN_OVERWRITE);
+	if (file == NULL) {
+		fputs("Error opening output file.\n", stderr);
+		return EXIT_FAILURE;
+	}
+
+	/* initialize the super block with sane values */
+	sqfs_super_init(&super, 4096, 0, SQFS_COMP_GZIP);
+
+	if (sqfs_super_write(&super, file)) {
+		fputs("Error witing super block.\n", stderr);
+		goto out_file;
+	}
+
+	/* write the file data for the readme */
+	if (file->write_at(file, sizeof(super), README, strlen(README))) {
+		fputs("Error writing file data!\n", stderr);
+		goto out_file;
+	}
+
+	/* create a compressor */
+	sqfs_compressor_config_init(&cfg, super.compression_id,
+				    super.block_size, 0);
+
+	cmp = sqfs_compressor_create(&cfg);
+	if (cmp == NULL) {
+		fputs("Error creating compressor.\n", stderr);
+		goto out_file;
+	}
+
+	/* create meta data writers for inodes and directories */
+	inode_m = sqfs_meta_writer_create(file, cmp, 0);
+	if (inode_m == NULL) {
+		fputs("Error creating inode meta data writer.\n", stderr);
+		goto out_cmp;
+	}
+
+	dir_m = sqfs_meta_writer_create(file, cmp,
+					SQFS_META_WRITER_KEEP_IN_MEMORY);
+	if (dir_m == NULL) {
+		fputs("Error creating directory meta data writer.\n", stderr);
+		goto out_im;
+	}
+
+	/* create a higher level directory writer on top of the meta writer */
+	dirwr = sqfs_dir_writer_create(dir_m, 0);
+	if (dirwr == NULL) {
+		fputs("Error creating directory writer.\n", stderr);
+		goto out_dm;
+	}
+
+	/* create an ID table */
+	idtbl = sqfs_id_table_create();
+	if (idtbl == NULL) {
+		fputs("Error creating ID table.\n", stderr);
+		goto out_dirwr;
+	}
+
+	/* generate inodes and directories */
+	super.inode_table_start = file->get_size(file);
+	inode_num = 1;
+
+	sqfs_dir_writer_begin(dirwr, 0);
+
+	for (i = 0; i < 42; ++i) {
+		sprintf(buffer, "%02u.sqfs", i + 1);
+
+		inode = create_file_inode(idtbl, inode_num++);
+		sqfs_meta_writer_get_position(inode_m, &block_start, &offset);
+		sqfs_meta_writer_write_inode(inode_m, inode);
+		sqfs_dir_writer_add_entry(dirwr, buffer,
+					  inode->base.inode_number,
+					  (block_start << 16) | offset,
+					  inode->base.mode);
+		free(inode);
+	}
+
+	inode = create_file_inode(idtbl, inode_num++);
+	inode->data.file.blocks_start = sizeof(super);
+	inode->data.file.file_size = strlen(README);
+	inode->block_sizes[0] = (1 << 24) | inode->data.file.file_size;
+
+	sqfs_meta_writer_get_position(inode_m, &block_start, &offset);
+	sqfs_meta_writer_write_inode(inode_m, inode);
+	sqfs_dir_writer_add_entry(dirwr, "README.txt",
+				  inode->base.inode_number,
+				  (block_start << 16) | offset,
+				  inode->base.mode);
+	free(inode);
+
+	sqfs_dir_writer_end(dirwr);
+
+	/* create an inode for the root directory */
+	inode = sqfs_dir_writer_create_inode(dirwr, 0, 0xFFFFFFFF, 0);
+
+	inode->base.mode = SQFS_INODE_MODE_DIR | 0755;
+	inode->base.inode_number = inode_num++;
+	sqfs_id_table_id_to_index(idtbl, 0, &inode->base.uid_idx);
+	sqfs_id_table_id_to_index(idtbl, 0, &inode->base.gid_idx);
+
+	sqfs_meta_writer_get_position(inode_m, &block_start, &offset);
+	super.root_inode_ref = (block_start << 16) | offset;
+	sqfs_meta_writer_write_inode(inode_m, inode);
+	free(inode);
+
+	/* flush the meta data to the file */
+	sqfs_meta_writer_flush(inode_m);
+	sqfs_meta_writer_flush(dir_m);
+
+	super.directory_table_start = file->get_size(file);
+	sqfs_meta_write_write_to_file(dir_m);
+
+	sqfs_id_table_write(idtbl, file, &super, cmp);
+
+	super.inode_count = inode_num - 2;
+	super.bytes_used = 4096;
+
+	if (sqfs_super_write(&super, file)) {
+		fputs("Error update the final super block.\n", stderr);
+		goto out_file;
+	}
+
+	add_padding(file);
+
+	/* cleanup */
+	status = EXIT_SUCCESS;
+	sqfs_id_table_destroy(idtbl);
+out_dirwr:
+	sqfs_dir_writer_destroy(dirwr);
+out_dm:
+	sqfs_meta_writer_destroy(dir_m);
+out_im:
+	sqfs_meta_writer_destroy(inode_m);
+out_cmp:
+	cmp->destroy(cmp);
+out_file:
+	file->destroy(file);
+	return status;
+}