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-rw-r--r--fs/romfs/inode.c648
1 files changed, 648 insertions, 0 deletions
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");
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 02:51:57 +0000