2 files changed, 655 insertions, 0 deletions

diff --git a/fs/romfs/Makefile b/fs/romfs/Makefile
new file mode 100644
index 000000000000..c95b21cf49a3
--- /dev/null
+++ b/fs/romfs/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the linux romfs filesystem routines.
+#
+
+obj-$(CONFIG_ROMFS_FS) += romfs.o
+
+romfs-objs := inode.o
diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
new file mode 100644
index 000000000000..c74f382dabba
--- /dev/null
+++ b/fs/romfs/inode.c
@@ -0,0 +1,648 @@
+/*
+ * ROMFS file system, Linux implementation
+ *
+ * Copyright (C) 1997-1999  Janos Farkas <chexum@shadow.banki.hu>
+ *
+ * Using parts of the minix filesystem
+ * Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * and parts of the affs filesystem additionally
+ * Copyright (C) 1993  Ray Burr
+ * Copyright (C) 1996  Hans-Joachim Widmaier
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Changes
+ *                                      Changed for 2.1.19 modules
+ *      Jan 1997                        Initial release
+ *      Jun 1997                        2.1.43+ changes
+ *                                      Proper page locking in readpage
+ *                                      Changed to work with 2.1.45+ fs
+ *      Jul 1997                        Fixed follow_link
+ *                      2.1.47
+ *                                      lookup shouldn't return -ENOENT
+ *                                      from Horst von Brand:
+ *                                        fail on wrong checksum
+ *                                        double unlock_super was possible
+ *                                        correct namelen for statfs
+ *                                      spotted by Bill Hawes:
+ *                                        readlink shouldn't iput()
+ *      Jun 1998        2.1.106         from Avery Pennarun: glibc scandir()
+ *                                        exposed a problem in readdir
+ *                      2.1.107         code-freeze spellchecker run
+ *      Aug 1998                        2.1.118+ VFS changes
+ *      Sep 1998        2.1.122         another VFS change (follow_link)
+ *      Apr 1999        2.2.7           no more EBADF checking in
+ *                                        lookup/readdir, use ERR_PTR
+ *      Jun 1999        2.3.6           d_alloc_root use changed
+ *                      2.3.9           clean up usage of ENOENT/negative
+ *                                        dentries in lookup
+ *                                      clean up page flags setting
+ *                                        (error, uptodate, locking) in
+ *                                        in readpage
+ *                                      use init_special_inode for
+ *                                        fifos/sockets (and streamline) in
+ *                                        read_inode, fix _ops table order
+ *      Aug 1999        2.3.16          __initfunc() => __init change
+ *      Oct 1999        2.3.24          page->owner hack obsoleted
+ *      Nov 1999        2.3.27          2.3.25+ page->offset => index change
+ */
+
+/* todo:
+ *      - see Documentation/filesystems/romfs.txt
+ *      - use allocated, not stack memory for file names?
+ *      - considering write access...
+ *      - network (tftp) files?
+ *      - merge back some _op tables
+ */
+
+/*
+ * Sorry about some optimizations and for some goto's.  I just wanted
+ * to squeeze some more bytes out of this code.. :)
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/romfs_fs.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+#include <linux/buffer_head.h>
+#include <linux/vfs.h>
+
+#include <asm/uaccess.h>
+
+struct romfs_inode_info {
+        unsigned long i_metasize;       /* size of non-data area */
+        unsigned long i_dataoffset;     /* from the start of fs */
+        struct inode vfs_inode;
+};
+
+/* instead of private superblock data */
+static inline unsigned long romfs_maxsize(struct super_block *sb)
+{
+        return (unsigned long)sb->s_fs_info;
+}
+
+static inline struct romfs_inode_info *ROMFS_I(struct inode *inode)
+{
+        return list_entry(inode, struct romfs_inode_info, vfs_inode);
+}
+
+static __u32
+romfs_checksum(void *data, int size)
+{
+        __u32 sum;
+        __be32 *ptr;
+
+        sum = 0; ptr = data;
+        size>>=2;
+        while (size>0) {
+                sum += be32_to_cpu(*ptr++);
+                size--;
+        }
+        return sum;
+}
+
+static struct super_operations romfs_ops;
+
+static int romfs_fill_super(struct super_block *s, void *data, int silent)
+{
+        struct buffer_head *bh;
+        struct romfs_super_block *rsb;
+        struct inode *root;
+        int sz;
+
+        /* I would parse the options here, but there are none.. :) */
+
+        sb_set_blocksize(s, ROMBSIZE);
+        s->s_maxbytes = 0xFFFFFFFF;
+
+        bh = sb_bread(s, 0);
+        if (!bh) {
+                /* XXX merge with other printk? */
+                printk ("romfs: unable to read superblock\n");
+                goto outnobh;
+        }
+
+        rsb = (struct romfs_super_block *)bh->b_data;
+        sz = be32_to_cpu(rsb->size);
+        if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1
+           || sz < ROMFH_SIZE) {
+                if (!silent)
+                        printk ("VFS: Can't find a romfs filesystem on dev "
+                                "%s.\n", s->s_id);
+                goto out;
+        }
+        if (romfs_checksum(rsb, min_t(int, sz, 512))) {
+                printk ("romfs: bad initial checksum on dev "
+                        "%s.\n", s->s_id);
+                goto out;
+        }
+
+        s->s_magic = ROMFS_MAGIC;
+        s->s_fs_info = (void *)(long)sz;
+
+        s->s_flags |= MS_RDONLY;
+
+        /* Find the start of the fs */
+        sz = (ROMFH_SIZE +
+              strnlen(rsb->name, ROMFS_MAXFN) + 1 + ROMFH_PAD)
+             & ROMFH_MASK;
+
+        s->s_op = &romfs_ops;
+        root = iget(s, sz);
+        if (!root)
+                goto out;
+
+        s->s_root = d_alloc_root(root);
+        if (!s->s_root)
+                goto outiput;
+
+        brelse(bh);
+        return 0;
+
+outiput:
+        iput(root);
+out:
+        brelse(bh);
+outnobh:
+        return -EINVAL;
+}
+
+/* That's simple too. */
+
+static int
+romfs_statfs(struct super_block *sb, struct kstatfs *buf)
+{
+        buf->f_type = ROMFS_MAGIC;
+        buf->f_bsize = ROMBSIZE;
+        buf->f_bfree = buf->f_bavail = buf->f_ffree;
+        buf->f_blocks = (romfs_maxsize(sb)+ROMBSIZE-1)>>ROMBSBITS;
+        buf->f_namelen = ROMFS_MAXFN;
+        return 0;
+}
+
+/* some helper routines */
+
+static int
+romfs_strnlen(struct inode *i, unsigned long offset, unsigned long count)
+{
+        struct buffer_head *bh;
+        unsigned long avail, maxsize, res;
+
+        maxsize = romfs_maxsize(i->i_sb);
+        if (offset >= maxsize)
+                return -1;
+
+        /* strnlen is almost always valid */
+        if (count > maxsize || offset+count > maxsize)
+                count = maxsize-offset;
+
+        bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
+        if (!bh)
+                return -1;              /* error */
+
+        avail = ROMBSIZE - (offset & ROMBMASK);
+        maxsize = min_t(unsigned long, count, avail);
+        res = strnlen(((char *)bh->b_data)+(offset&ROMBMASK), maxsize);
+        brelse(bh);
+
+        if (res < maxsize)
+                return res;             /* found all of it */
+
+        while (res < count) {
+                offset += maxsize;
+
+                bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
+                if (!bh)
+                        return -1;
+                maxsize = min_t(unsigned long, count - res, ROMBSIZE);
+                avail = strnlen(bh->b_data, maxsize);
+                res += avail;
+                brelse(bh);
+                if (avail < maxsize)
+                        return res;
+        }
+        return res;
+}
+
+static int
+romfs_copyfrom(struct inode *i, void *dest, unsigned long offset, unsigned long count)
+{
+        struct buffer_head *bh;
+        unsigned long avail, maxsize, res;
+
+        maxsize = romfs_maxsize(i->i_sb);
+        if (offset >= maxsize || count > maxsize || offset+count>maxsize)
+                return -1;
+
+        bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
+        if (!bh)
+                return -1;              /* error */
+
+        avail = ROMBSIZE - (offset & ROMBMASK);
+        maxsize = min_t(unsigned long, count, avail);
+        memcpy(dest, ((char *)bh->b_data) + (offset & ROMBMASK), maxsize);
+        brelse(bh);
+
+        res = maxsize;                  /* all of it */
+
+        while (res < count) {
+                offset += maxsize;
+                dest += maxsize;
+
+                bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
+                if (!bh)
+                        return -1;
+                maxsize = min_t(unsigned long, count - res, ROMBSIZE);
+                memcpy(dest, bh->b_data, maxsize);
+                brelse(bh);
+                res += maxsize;
+        }
+        return res;
+}
+
+static unsigned char romfs_dtype_table[] = {
+        DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
+};
+
+static int
+romfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+        struct inode *i = filp->f_dentry->d_inode;
+        struct romfs_inode ri;
+        unsigned long offset, maxoff;
+        int j, ino, nextfh;
+        int stored = 0;
+        char fsname[ROMFS_MAXFN];       /* XXX dynamic? */
+
+        lock_kernel();
+
+        maxoff = romfs_maxsize(i->i_sb);
+
+        offset = filp->f_pos;
+        if (!offset) {
+                offset = i->i_ino & ROMFH_MASK;
+                if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
+                        goto out;
+                offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
+        }
+
+        /* Not really failsafe, but we are read-only... */
+        for(;;) {
+                if (!offset || offset >= maxoff) {
+                        offset = maxoff;
+                        filp->f_pos = offset;
+                        goto out;
+                }
+                filp->f_pos = offset;
+
+                /* Fetch inode info */
+                if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
+                        goto out;
+
+                j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1);
+                if (j < 0)
+                        goto out;
+
+                fsname[j]=0;
+                romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j);
+
+                ino = offset;
+                nextfh = be32_to_cpu(ri.next);
+                if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
+                        ino = be32_to_cpu(ri.spec);
+                if (filldir(dirent, fsname, j, offset, ino,
+                            romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0) {
+                        goto out;
+                }
+                stored++;
+                offset = nextfh & ROMFH_MASK;
+        }
+out:
+        unlock_kernel();
+        return stored;
+}
+
+static struct dentry *
+romfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+        unsigned long offset, maxoff;
+        int fslen, res;
+        struct inode *inode;
+        char fsname[ROMFS_MAXFN];       /* XXX dynamic? */
+        struct romfs_inode ri;
+        const char *name;               /* got from dentry */
+        int len;
+
+        res = -EACCES;                  /* placeholder for "no data here" */
+        offset = dir->i_ino & ROMFH_MASK;
+        lock_kernel();
+        if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
+                goto out;
+
+        maxoff = romfs_maxsize(dir->i_sb);
+        offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
+
+        /* OK, now find the file whose name is in "dentry" in the
+         * directory specified by "dir".  */
+
+        name = dentry->d_name.name;
+        len = dentry->d_name.len;
+
+        for(;;) {
+                if (!offset || offset >= maxoff)
+                        goto out0;
+                if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
+                        goto out;
+
+                /* try to match the first 16 bytes of name */
+                fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, ROMFH_SIZE);
+                if (len < ROMFH_SIZE) {
+                        if (len == fslen) {
+                                /* both are shorter, and same size */
+                                romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
+                                if (strncmp (name, fsname, len) == 0)
+                                        break;
+                        }
+                } else if (fslen >= ROMFH_SIZE) {
+                        /* both are longer; XXX optimize max size */
+                        fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, sizeof(fsname)-1);
+                        if (len == fslen) {
+                                romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
+                                if (strncmp(name, fsname, len) == 0)
+                                        break;
+                        }
+                }
+                /* next entry */
+                offset = be32_to_cpu(ri.next) & ROMFH_MASK;
+        }
+
+        /* Hard link handling */
+        if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
+                offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
+
+        if ((inode = iget(dir->i_sb, offset)))
+                goto outi;
+
+        /*
+         * it's a bit funky, _lookup needs to return an error code
+         * (negative) or a NULL, both as a dentry.  ENOENT should not
+         * be returned, instead we need to create a negative dentry by
+         * d_add(dentry, NULL); and return 0 as no error.
+         * (Although as I see, it only matters on writable file
+         * systems).
+         */
+
+out0:   inode = NULL;
+outi:   res = 0;
+        d_add (dentry, inode);
+
+out:    unlock_kernel();
+        return ERR_PTR(res);
+}
+
+/*
+ * Ok, we do readpage, to be able to execute programs.  Unfortunately,
+ * we can't use bmap, since we may have looser alignments.
+ */
+
+static int
+romfs_readpage(struct file *file, struct page * page)
+{
+        struct inode *inode = page->mapping->host;
+        unsigned long offset, avail, readlen;
+        void *buf;
+        int result = -EIO;
+
+        page_cache_get(page);
+        lock_kernel();
+        buf = kmap(page);
+        if (!buf)
+                goto err_out;
+
+        /* 32 bit warning -- but not for us :) */
+        offset = page->index << PAGE_CACHE_SHIFT;
+        if (offset < inode->i_size) {
+                avail = inode->i_size-offset;
+                readlen = min_t(unsigned long, avail, PAGE_SIZE);
+                if (romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen) == readlen) {
+                        if (readlen < PAGE_SIZE) {
+                                memset(buf + readlen,0,PAGE_SIZE-readlen);
+                        }
+                        SetPageUptodate(page);
+                        result = 0;
+                }
+        }
+        if (result) {
+                memset(buf, 0, PAGE_SIZE);
+                SetPageError(page);
+        }
+        flush_dcache_page(page);
+
+        unlock_page(page);
+
+        kunmap(page);
+err_out:
+        page_cache_release(page);
+        unlock_kernel();
+
+        return result;
+}
+
+/* Mapping from our types to the kernel */
+
+static struct address_space_operations romfs_aops = {
+        .readpage = romfs_readpage
+};
+
+static struct file_operations romfs_dir_operations = {
+        .read           = generic_read_dir,
+        .readdir        = romfs_readdir,
+};
+
+static struct inode_operations romfs_dir_inode_operations = {
+        .lookup         = romfs_lookup,
+};
+
+static mode_t romfs_modemap[] =
+{
+        0, S_IFDIR+0644, S_IFREG+0644, S_IFLNK+0777,
+        S_IFBLK+0600, S_IFCHR+0600, S_IFSOCK+0644, S_IFIFO+0644
+};
+
+static void
+romfs_read_inode(struct inode *i)
+{
+        int nextfh, ino;
+        struct romfs_inode ri;
+
+        ino = i->i_ino & ROMFH_MASK;
+        i->i_mode = 0;
+
+        /* Loop for finding the real hard link */
+        for(;;) {
+                if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) {
+                        printk("romfs: read error for inode 0x%x\n", ino);
+                        return;
+                }
+                /* XXX: do romfs_checksum here too (with name) */
+
+                nextfh = be32_to_cpu(ri.next);
+                if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
+                        break;
+
+                ino = be32_to_cpu(ri.spec) & ROMFH_MASK;
+        }
+
+        i->i_nlink = 1;         /* Hard to decide.. */
+        i->i_size = be32_to_cpu(ri.size);
+        i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
+        i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
+        i->i_uid = i->i_gid = 0;
+
+        /* Precalculate the data offset */
+        ino = romfs_strnlen(i, ino+ROMFH_SIZE, ROMFS_MAXFN);
+        if (ino >= 0)
+                ino = ((ROMFH_SIZE+ino+1+ROMFH_PAD)&ROMFH_MASK);
+        else
+                ino = 0;
+
+        ROMFS_I(i)->i_metasize = ino;
+        ROMFS_I(i)->i_dataoffset = ino+(i->i_ino&ROMFH_MASK);
+
+        /* Compute permissions */
+        ino = romfs_modemap[nextfh & ROMFH_TYPE];
+        /* only "normal" files have ops */
+        switch (nextfh & ROMFH_TYPE) {
+                case 1:
+                        i->i_size = ROMFS_I(i)->i_metasize;
+                        i->i_op = &romfs_dir_inode_operations;
+                        i->i_fop = &romfs_dir_operations;
+                        if (nextfh & ROMFH_EXEC)
+                                ino |= S_IXUGO;
+                        i->i_mode = ino;
+                        break;
+                case 2:
+                        i->i_fop = &generic_ro_fops;
+                        i->i_data.a_ops = &romfs_aops;
+                        if (nextfh & ROMFH_EXEC)
+                                ino |= S_IXUGO;
+                        i->i_mode = ino;
+                        break;
+                case 3:
+                        i->i_op = &page_symlink_inode_operations;
+                        i->i_data.a_ops = &romfs_aops;
+                        i->i_mode = ino | S_IRWXUGO;
+                        break;
+                default:
+                        /* depending on MBZ for sock/fifos */
+                        nextfh = be32_to_cpu(ri.spec);
+                        init_special_inode(i, ino,
+                                        MKDEV(nextfh>>16,nextfh&0xffff));
+        }
+}
+
+static kmem_cache_t * romfs_inode_cachep;
+
+static struct inode *romfs_alloc_inode(struct super_block *sb)
+{
+        struct romfs_inode_info *ei;
+        ei = (struct romfs_inode_info *)kmem_cache_alloc(romfs_inode_cachep, SLAB_KERNEL);
+        if (!ei)
+                return NULL;
+        return &ei->vfs_inode;
+}
+
+static void romfs_destroy_inode(struct inode *inode)
+{
+        kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
+}
+
+static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
+{
+        struct romfs_inode_info *ei = (struct romfs_inode_info *) foo;
+
+        if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+            SLAB_CTOR_CONSTRUCTOR)
+                inode_init_once(&ei->vfs_inode);
+}
+ 
+static int init_inodecache(void)
+{
+        romfs_inode_cachep = kmem_cache_create("romfs_inode_cache",
+                                             sizeof(struct romfs_inode_info),
+                                             0, SLAB_RECLAIM_ACCOUNT,
+                                             init_once, NULL);
+        if (romfs_inode_cachep == NULL)
+                return -ENOMEM;
+        return 0;
+}
+
+static void destroy_inodecache(void)
+{
+        if (kmem_cache_destroy(romfs_inode_cachep))
+                printk(KERN_INFO "romfs_inode_cache: not all structures were freed\n");
+}
+
+static int romfs_remount(struct super_block *sb, int *flags, char *data)
+{
+        *flags |= MS_RDONLY;
+        return 0;
+}
+
+static struct super_operations romfs_ops = {
+        .alloc_inode    = romfs_alloc_inode,
+        .destroy_inode  = romfs_destroy_inode,
+        .read_inode     = romfs_read_inode,
+        .statfs         = romfs_statfs,
+        .remount_fs     = romfs_remount,
+};
+
+static struct super_block *romfs_get_sb(struct file_system_type *fs_type,
+        int flags, const char *dev_name, void *data)
+{
+        return get_sb_bdev(fs_type, flags, dev_name, data, romfs_fill_super);
+}
+
+static struct file_system_type romfs_fs_type = {
+        .owner          = THIS_MODULE,
+        .name           = "romfs",
+        .get_sb         = romfs_get_sb,
+        .kill_sb        = kill_block_super,
+        .fs_flags       = FS_REQUIRES_DEV,
+};
+
+static int __init init_romfs_fs(void)
+{
+        int err = init_inodecache();
+        if (err)
+                goto out1;
+        err = register_filesystem(&romfs_fs_type);
+        if (err)
+                goto out;
+        return 0;
+out:
+        destroy_inodecache();
+out1:
+        return err;
+}
+
+static void __exit exit_romfs_fs(void)
+{
+        unregister_filesystem(&romfs_fs_type);
+        destroy_inodecache();
+}
+
+/* Yes, works even as a module... :) */
+
+module_init(init_romfs_fs)
+module_exit(exit_romfs_fs)
+MODULE_LICENSE("GPL");