squashfuse_extract

[probonopd]

If would be nice if there was a tool to extract rather than list the files in a squashfs file, similar to squashfuse_ls.

[probonopd]

@vasi gave me hints to use the following:

• sqfs_traverse_*: https://github.com/vasi/squashfuse/blob/master/traverse.h#L33 . This lets you look at every file in the filesystem, gives you a sqfs_traverse structure that contains a sqfs_dir_entry, which itself gives you a sqfs_inode_id .
• sqfs_inode_get: https://github.com/vasi/squashfuse/blob/master/fs.h#L119 From an inode id, this gives you an sqfs_inode structure. That contains various information about the file/dir/socket/whatever. https://github.com/vasi/squashfuse/blob/master/fs.h#L54
• The types of "whatever" are in the inode's base.inode_type -

  squashfuse/squashfs_fs.h

  Lines 79 to 93 in 78360b7

  	/* Max number of types and file types */
  	#define SQUASHFS_DIR_TYPE 1
  	#define SQUASHFS_REG_TYPE 2
  	#define SQUASHFS_SYMLINK_TYPE 3
  	#define SQUASHFS_BLKDEV_TYPE 4
  	#define SQUASHFS_CHRDEV_TYPE 5
  	#define SQUASHFS_FIFO_TYPE 6
  	#define SQUASHFS_SOCKET_TYPE 7
  	#define SQUASHFS_LDIR_TYPE 8
  	#define SQUASHFS_LREG_TYPE 9
  	#define SQUASHFS_LSYMLINK_TYPE 10
  	#define SQUASHFS_LBLKDEV_TYPE 11
  	#define SQUASHFS_LCHRDEV_TYPE 12
  	#define SQUASHFS_LFIFO_TYPE 13
  	#define SQUASHFS_LSOCKET_TYPE 14

• sqfs_read_range: https://github.com/vasi/squashfuse/blob/master/file.h#L60 Given a sqfs_inode, this reads some data from it!
• Also, be careful about reading the file all at once. What if the file size is 10 GB? Your program will attempt to malloc() a giant buffer! You can replace one giant read with multiple small ones!
• To get just one file, you don't have to traverse the whole archive. You can just use sqfs_lookup_path(): https://github.com/vasi/squashfuse/blob/master/dir.h#L72

[probonopd]

I have started a (very) simplistic tool to extract regular files and directories from a squashfs file at https://github.com/probonopd/squashfuse/blob/master/extract.c