patch-1.3.94 linux/fs/affs/namei.c

• Lines: 188
• Date: Sun Feb 25 19:14:29 1996
• Orig file: v1.3.93/linux/fs/affs/namei.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/fs/affs/namei.c linux/fs/affs/namei.c
@@ -0,0 +1,187 @@
+/*
+ *  linux/fs/affs/namei.c
+ *
+ *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
+ *
+ *  (C) 1992  Eric Youngdale Modified for ISO9660 filesystem.
+ *
+ *  (C) 1991  Linus Torvalds - minix filesystem
+ */
+
+#include <linux/sched.h>
+#include <linux/affs_fs.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <asm/segment.h>
+
+#include <linux/errno.h>
+
+
+static inline int namecompare(int len, int maxlen,
+	const char * name, const char * buffer)
+{
+	if (len >= maxlen || !buffer[len]) {
+		return strncmp (name, buffer, len) == 0;
+	}
+	return 0;
+}
+
+/*
+ * ok, we cannot use strncmp, as the name is not in our data space.
+ * Thus we'll have to use affs_match. No big problem. Match also makes
+ * some sanity tests.
+ *
+ * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
+ */
+static int affs_match(int len,const char * name, char * compare, int dlen)
+{
+	if (!compare) return 0;
+
+	/* "" means "." ---> so paths like "/usr/lib//libc.a" work */
+	if (!len && dlen == 1 && compare[0] == '.')
+		return 1;
+	
+#if 0
+	if (len <= 2) printk("Match: %d %d %s %d %d \n",len,dlen,compare,de->name[0], dlen);
+#endif
+	
+	return namecompare(len,dlen,name,compare);
+}
+
+/* Avoid pulling in ctype stuff. */
+
+static int affs_toupper (int ch)
+{
+	if (ch >= 'a' && ch <= 'z')
+		ch -= ('a' - 'A');
+	return ch;
+}
+
+static int affs_hash_name (const char *name, int len)
+{
+	int i, x;
+
+	x = len;
+	for (i = 0; i < len; i++)
+		x = (x * 13 + affs_toupper (name[i])) & 0x7ff;
+	return x % 72;  /* FIXME: Assumes 512 byte blocks. */
+}
+
+static struct buffer_head *affs_find_entry(struct inode *dir,
+	const char *name, int namelen, int *ino)
+{
+	struct buffer_head *bh;
+	void *dir_data;
+	int key;
+
+	*ino = 0;
+
+	bh = affs_pread (dir, dir->i_ino, &dir_data);
+	if (!bh)
+		return NULL;
+
+	if (affs_match (namelen, name, ".", 1)) {
+		*ino = dir->i_ino;
+		return bh;
+	}
+	if (affs_match (namelen, name, "..", 2)) {
+		*ino = affs_parent_ino (dir);
+		return bh;
+	}
+	key = affs_get_key_entry (AFFS_I2BSIZE (dir), dir_data,
+				  affs_hash_name (name, namelen));
+
+	for (;;) {
+		char *cname;
+		int cnamelen;
+
+		brelse (bh);
+		if (key <= 0)
+			return NULL;
+		bh = affs_pread (dir, key, &dir_data);
+		if (!bh)
+			return NULL;
+		cnamelen = affs_get_file_name (AFFS_I2BSIZE (dir),
+					       dir_data, &cname);
+		if (affs_match (namelen, name, cname, cnamelen))
+			break;
+		key = affs_get_fh_hash_link (AFFS_I2BSIZE (dir), dir_data);
+	}
+		
+	*ino = key;
+
+	return bh;
+}
+
+int affs_lookup(struct inode * dir,const char * name, int len,
+	struct inode ** result)
+{
+	int ino;
+	struct buffer_head *bh;
+
+	*result = NULL;
+	if (!dir)
+		return -ENOENT;
+
+#ifdef DEBUG
+	printk ("lookup: %d %d\n", dir->i_ino, len);
+#endif
+
+	if (!S_ISDIR(dir->i_mode)) {
+		iput(dir);
+		return -ENOENT;
+	}
+	if (!(bh = affs_find_entry(dir, name, len, &ino))) {
+	  iput(dir);
+	  return -ENOENT;
+	}
+	brelse(bh);
+	if (!(*result = iget(dir->i_sb, ino))) {
+		iput(dir);
+		return -EACCES;
+	}
+	iput (dir);
+	return 0;
+
+#if 0
+	ino = 0;
+	while(cache.lock);
+	cache.lock = 1;
+	if (dir->i_dev == cache.dev && 
+	    dir->i_ino == cache.dir &&
+	    len == cache.dlen && 
+	    affs_match(len, name, cache.filename, cache.dlen))
+	  {
+	    ino = cache.ino;
+	    ino_back = dir->i_ino;
+	    /* These two cases are special, but since they are at the start
+	       of the directory, we can just as easily search there */
+	    if (cache.dlen == 1 && cache.filename[0] == '.') ino = 0;
+	    if (cache.dlen == 2 && cache.filename[0] == '.' && 
+		cache.filename[1] == '.') ino = 0;
+	  };
+	cache.lock = 0;
+
+	if (!ino) {
+	  if (!(bh = affs_find_entry(dir,name,len, &ino, &ino_back))) {
+	    iput(dir);
+	    return -ENOENT;
+	  }
+	  brelse(bh);
+	};
+
+	if (!(*result = iget(dir->i_sb,ino))) {
+		iput(dir);
+		return -EACCES;
+	}
+
+	/* We need this backlink for the .. entry */
+	
+	if (ino_back) (*result)->u.affs_i.i_backlink = ino_back; 
+	
+	iput(dir);
+	return 0;
+#endif
+}