1 /* 2 * link.c --- create links in a ext2fs directory 3 * 4 * Copyright (C) 1993, 1994 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include <stdio.h> 13 #include <string.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 18 #include "ext2_fs.h" 19 #include "ext2fs.h" 20 21 struct link_struct { 22 ext2_filsys fs; 23 const char *name; 24 int namelen; 25 ext2_ino_t inode; 26 int flags; 27 int done; 28 unsigned int blocksize; 29 errcode_t err; 30 struct ext2_super_block *sb; 31 }; 32 33 static int link_proc(struct ext2_dir_entry *dirent, 34 int offset, 35 int blocksize, 36 char *buf, 37 void *priv_data) 38 { 39 struct link_struct *ls = (struct link_struct *) priv_data; 40 struct ext2_dir_entry *next; 41 unsigned int rec_len, min_rec_len, curr_rec_len; 42 int ret = 0; 43 44 rec_len = EXT2_DIR_REC_LEN(ls->namelen); 45 46 ls->err = ext2fs_get_rec_len(ls->fs, dirent, &curr_rec_len); 47 if (ls->err) 48 return DIRENT_ABORT; 49 50 /* 51 * See if the following directory entry (if any) is unused; 52 * if so, absorb it into this one. 53 */ 54 next = (struct ext2_dir_entry *) (buf + offset + curr_rec_len); 55 if ((offset + curr_rec_len < blocksize - 8) && 56 (next->inode == 0) && 57 (offset + curr_rec_len + next->rec_len <= blocksize)) { 58 curr_rec_len += next->rec_len; 59 ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent); 60 if (ls->err) 61 return DIRENT_ABORT; 62 ret = DIRENT_CHANGED; 63 } 64 65 /* 66 * If the directory entry is used, see if we can split the 67 * directory entry to make room for the new name. If so, 68 * truncate it and return. 69 */ 70 if (dirent->inode) { 71 min_rec_len = EXT2_DIR_REC_LEN(dirent->name_len & 0xFF); 72 if (curr_rec_len < (min_rec_len + rec_len)) 73 return ret; 74 rec_len = curr_rec_len - min_rec_len; 75 ls->err = ext2fs_set_rec_len(ls->fs, min_rec_len, dirent); 76 if (ls->err) 77 return DIRENT_ABORT; 78 next = (struct ext2_dir_entry *) (buf + offset + 79 dirent->rec_len); 80 next->inode = 0; 81 next->name_len = 0; 82 ls->err = ext2fs_set_rec_len(ls->fs, rec_len, next); 83 if (ls->err) 84 return DIRENT_ABORT; 85 return DIRENT_CHANGED; 86 } 87 88 /* 89 * If we get this far, then the directory entry is not used. 90 * See if we can fit the request entry in. If so, do it. 91 */ 92 if (curr_rec_len < rec_len) 93 return ret; 94 dirent->inode = ls->inode; 95 dirent->name_len = ls->namelen; 96 strncpy(dirent->name, ls->name, ls->namelen); 97 if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE) 98 dirent->name_len |= (ls->flags & 0x7) << 8; 99 100 ls->done++; 101 return DIRENT_ABORT|DIRENT_CHANGED; 102 } 103 104 /* 105 * Note: the low 3 bits of the flags field are used as the directory 106 * entry filetype. 107 */ 108 #ifdef __TURBOC__ 109 #pragma argsused 110 #endif 111 errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name, 112 ext2_ino_t ino, int flags) 113 { 114 errcode_t retval; 115 struct link_struct ls; 116 struct ext2_inode inode; 117 118 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 119 120 if (!(fs->flags & EXT2_FLAG_RW)) 121 return EXT2_ET_RO_FILSYS; 122 123 ls.fs = fs; 124 ls.name = name; 125 ls.namelen = name ? strlen(name) : 0; 126 ls.inode = ino; 127 ls.flags = flags; 128 ls.done = 0; 129 ls.sb = fs->super; 130 ls.blocksize = fs->blocksize; 131 ls.err = 0; 132 133 retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY, 134 0, link_proc, &ls); 135 if (retval) 136 return retval; 137 if (ls.err) 138 return ls.err; 139 140 if (!ls.done) 141 return EXT2_ET_DIR_NO_SPACE; 142 143 if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0) 144 return retval; 145 146 if (inode.i_flags & EXT2_INDEX_FL) { 147 inode.i_flags &= ~EXT2_INDEX_FL; 148 if ((retval = ext2fs_write_inode(fs, dir, &inode)) != 0) 149 return retval; 150 } 151 152 return 0; 153 } 154
