1/* vi: set sw=4 ts=4: */ 2/* 3 * link.c --- create links in a ext2fs directory 4 * 5 * Copyright (C) 1993, 1994 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12 13#include <stdio.h> 14#include <string.h> 15#if HAVE_UNISTD_H 16#include <unistd.h> 17#endif 18 19#include "ext2_fs.h" 20#include "ext2fs.h" 21 22struct link_struct { 23 const char *name; 24 int namelen; 25 ext2_ino_t inode; 26 int flags; 27 int done; 28 struct ext2_super_block *sb; 29}; 30 31static int link_proc(struct ext2_dir_entry *dirent, 32 int offset, 33 int blocksize, 34 char *buf, 35 void *priv_data) 36{ 37 struct link_struct *ls = (struct link_struct *) priv_data; 38 struct ext2_dir_entry *next; 39 int rec_len, min_rec_len; 40 int ret = 0; 41 42 rec_len = EXT2_DIR_REC_LEN(ls->namelen); 43 44 /* 45 * See if the following directory entry (if any) is unused; 46 * if so, absorb it into this one. 47 */ 48 next = (struct ext2_dir_entry *) (buf + offset + dirent->rec_len); 49 if ((offset + dirent->rec_len < blocksize - 8) && 50 (next->inode == 0) && 51 (offset + dirent->rec_len + next->rec_len <= blocksize)) { 52 dirent->rec_len += next->rec_len; 53 ret = DIRENT_CHANGED; 54 } 55 56 /* 57 * If the directory entry is used, see if we can split the 58 * directory entry to make room for the new name. If so, 59 * truncate it and return. 60 */ 61 if (dirent->inode) { 62 min_rec_len = EXT2_DIR_REC_LEN(dirent->name_len & 0xFF); 63 if (dirent->rec_len < (min_rec_len + rec_len)) 64 return ret; 65 rec_len = dirent->rec_len - min_rec_len; 66 dirent->rec_len = min_rec_len; 67 next = (struct ext2_dir_entry *) (buf + offset + 68 dirent->rec_len); 69 next->inode = 0; 70 next->name_len = 0; 71 next->rec_len = rec_len; 72 return DIRENT_CHANGED; 73 } 74 75 /* 76 * If we get this far, then the directory entry is not used. 77 * See if we can fit the request entry in. If so, do it. 78 */ 79 if (dirent->rec_len < rec_len) 80 return ret; 81 dirent->inode = ls->inode; 82 dirent->name_len = ls->namelen; 83 strncpy(dirent->name, ls->name, ls->namelen); 84 if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE) 85 dirent->name_len |= (ls->flags & 0x7) << 8; 86 87 ls->done++; 88 return DIRENT_ABORT|DIRENT_CHANGED; 89} 90 91/* 92 * Note: the low 3 bits of the flags field are used as the directory 93 * entry filetype. 94 */ 95#ifdef __TURBOC__ 96# pragma argsused 97#endif 98errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name, 99 ext2_ino_t ino, int flags) 100{ 101 errcode_t retval; 102 struct link_struct ls; 103 struct ext2_inode inode; 104 105 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 106 107 if (!(fs->flags & EXT2_FLAG_RW)) 108 return EXT2_ET_RO_FILSYS; 109 110 ls.name = name; 111 ls.namelen = name ? strlen(name) : 0; 112 ls.inode = ino; 113 ls.flags = flags; 114 ls.done = 0; 115 ls.sb = fs->super; 116 117 retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY, 118 0, link_proc, &ls); 119 if (retval) 120 return retval; 121 122 if (!ls.done) 123 return EXT2_ET_DIR_NO_SPACE; 124 125 if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0) 126 return retval; 127 128 if (inode.i_flags & EXT2_INDEX_FL) { 129 inode.i_flags &= ~EXT2_INDEX_FL; 130 if ((retval = ext2fs_write_inode(fs, dir, &inode)) != 0) 131 return retval; 132 } 133 134 return 0; 135} 136