Add new function to the libext2fs library, ext2fs_dirhash, which

calculates the hash of a filename for indexed directories.

diff --git a/debugfs/ChangeLog b/debugfs/ChangeLog
index 2940820..003b559 100644 (file)
--- a/debugfs/ChangeLog
+++ b/debugfs/ChangeLog
@@ -1,3 +1,8 @@
+2002-03-11  Theodore Tso  <tytso@mit.edu>
+
+       * htree.c (htree_dump_leaf_node): Use the ext2_dirhash function
+               instead of a local static function.
+
 2002-03-08  Theodore Tso  <tytso@mit.edu>
 
        * Release of E2fsprogs 1.27

diff --git a/debugfs/htree.c b/debugfs/htree.c
index 86909a7..a6d4eef 100644 (file)
--- a/debugfs/htree.c
+++ b/debugfs/htree.c
@@ -29,21 +29,6 @@ extern int optreset;         /* defined by BSD, but not others */
 
 static FILE *pager;
 
-static unsigned dx_hack_hash (const char *name, int len)
-{
-       __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
-       while (len--) {
-               __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
-               
-               if (hash & 0x80000000) hash -= 0x7fffffff;
-               hash1 = hash0;
-               hash0 = hash;
-       }
-       return hash0;
-}
-
-#define dx_hash(s,n) (dx_hack_hash(s,n) << 1)
-
 static void htree_dump_leaf_node(ext2_filsys fs, ext2_ino_t ino,
                                 struct ext2_inode *inode,
                                 blk_t blk, char *buf)
@@ -54,6 +39,7 @@ static void htree_dump_leaf_node(ext2_filsys fs, ext2_ino_t ino,
        char            name[EXT2_NAME_LEN];
        char            tmp[EXT2_NAME_LEN + 16];
        blk_t           pblk;
+       ext2_dirhash_t  hash;
        
        errcode = ext2fs_bmap(fs, ino, inode, buf, 0, blk, &pblk);
        if (errcode) {
@@ -82,8 +68,12 @@ static void htree_dump_leaf_node(ext2_filsys fs, ext2_ino_t ino,
                        (dirent->name_len & 0xFF) : EXT2_NAME_LEN;
                strncpy(name, dirent->name, thislen);
                name[thislen] = '\0';
+               errcode = ext2fs_dirhash(0, name, thislen, &hash);
+               if (errcode)
+                       com_err("htree_dump_leaf_node", errcode,
+                               "while calculating hash");
                sprintf(tmp, "%u 0x%08x (%d) %s   ", dirent->inode,
-                      dx_hash(name, thislen), dirent->rec_len, name);
+                       hash, dirent->rec_len, name);
                thislen = strlen(tmp);
                if (col + thislen > 80) {
                        fprintf(pager, "\n");
@@ -266,12 +256,19 @@ errout:
  */
 void do_dx_hash(int argc, char *argv[])
 {
+       ext2_dirhash_t hash;
+       errcode_t       err;
+       
        if (argc != 2) {
                com_err(argv[0], 0, "usage: dx_hash filename");
                return;
        }
-       printf("Hash of %s is 0x%0x\n", argv[1],
-              dx_hash(argv[1], strlen(argv[1])));
+       err = ext2fs_dirhash(0, argv[1], strlen(argv[1]), &hash);
+       if (err) {
+               com_err(argv[0], err, "while caclulating hash");
+               return;
+       }
+       printf("Hash of %s is 0x%0x\n", argv[1], hash);
 }
 
 /*

diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index 952c51c..bd58b99 100644 (file)
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,3 +1,10 @@
+2002-03-11  Theodore Tso  <tytso@mit.edu>
+
+       * ext2_err.et.in (EXT2_ET_DIRHASH_UNSUPP): New error code
+
+       * dirhash.c (ext2fs_dirhash): New function which calculates the
+               hash for a filename in an indexed directory.
+
 2002-03-08  Theodore Tso  <tytso@mit.edu>
 
        * Release of E2fsprogs 1.27

diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index 6297abf..b302b08 100644 (file)
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -30,6 +30,7 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_OBJS) $(E2IMAGE_LIB_OBJS) \
        dblist.o \
        dblist_dir.o \
        dirblock.o \
+       dirhash.o \
        dir_iterate.o \
        expanddir.o \
        ext_attr.o \
@@ -79,6 +80,7 @@ SRCS= ext2_err.c \
        $(srcdir)/dblist.c \
        $(srcdir)/dblist_dir.c \
        $(srcdir)/dirblock.c \
+       $(srcdir)/dirhash.c \
        $(srcdir)/dir_iterate.c \
        $(srcdir)/dupfs.c \
        $(srcdir)/expanddir.c \

diff --git a/lib/ext2fs/dirhash.c b/lib/ext2fs/dirhash.c
new file mode 100644 (file)
index 0000000..5f71c6d
--- /dev/null
+++ b/lib/ext2fs/dirhash.c
@@ -0,0 +1,51 @@
+/*
+ * dirhash.c -- Calculate the hash of a directory entry
+ *
+ * Copyright (c) 2001  Daniel Phillips
+ * 
+ * Copyright (c) 2002 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+static ext2_dirhash_t dx_hack_hash (const char *name, int len)
+{
+       __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+       while (len--) {
+               __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
+               
+               if (hash & 0x80000000) hash -= 0x7fffffff;
+               hash1 = hash0;
+               hash0 = hash;
+       }
+       return hash0;
+}
+
+/*
+ * Returns the hash of a filename.  If len is 0 and name is NULL, then
+ * this function can be used to test whether or not a hash version is
+ * supported.
+ */
+errcode_t ext2fs_dirhash(int version, const char *name, int len,
+                        ext2_dirhash_t *ret_hash)
+{
+       __u32   hash;
+
+       if (version == 0)
+               hash = dx_hack_hash(name, len);
+       else {
+               *ret_hash = 0;
+               return EXT2_ET_DIRHASH_UNSUPP;
+       }
+       *ret_hash = hash;
+       return 0;
+               
+}

diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index ab36c9d..c22e5d8 100644 (file)
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -275,5 +275,8 @@ ec  EXT2_ET_LOAD_EXT_JOURNAL,
 ec     EXT2_ET_NO_JOURNAL,
        "Journal not found"
 
+ec     EXT2_ET_DIRHASH_UNSUPP,
+       "Directory hash unsupported"
+
        end
 

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 15d0b6f..d55cd50 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -65,6 +65,7 @@ typedef __u32         blk_t;
 typedef __u32          dgrp_t;
 typedef __u32          ext2_off_t;
 typedef __s64          e2_blkcnt_t;
+typedef __u32          ext2_dirhash_t;
 
 #if EXT2_FLAT_INCLUDES
 #include "com_err.h"
@@ -406,6 +407,7 @@ typedef struct ext2_icount *ext2_icount_t;
 #define EXT2_LIB_FEATURE_COMPAT_SUPP   (EXT2_FEATURE_COMPAT_DIR_PREALLOC|\
                                         EXT2_FEATURE_COMPAT_IMAGIC_INODES|\
                                         EXT3_FEATURE_COMPAT_HAS_JOURNAL|\
+                                        EXT2_FEATURE_COMPAT_DIR_INDEX|\
                                         EXT2_FEATURE_COMPAT_EXT_ATTR)
 
 /* This #ifdef is temporary until compression is fully supported */
@@ -599,6 +601,11 @@ extern errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
 extern errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
                                        void *buf);
 
+/* dirhash.c */
+extern errcode_t ext2fs_dirhash(int version, const char *name, int len,
+                               ext2_dirhash_t *ret_hash);
+
+
 /* dir_iterate.c */
 extern errcode_t ext2fs_dir_iterate(ext2_filsys fs, 
                              ext2_ino_t dir,