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 if (ls->done) 45 return DIRENT_ABORT; 46 47 rec_len = EXT2_DIR_REC_LEN(ls->namelen); 48 49 ls->err = ext2fs_get_rec_len(ls->fs, dirent, &curr_rec_len); 50 if (ls->err) 51 return DIRENT_ABORT; 52 53 /* 54 * See if the following directory entry (if any) is unused; 55 * if so, absorb it into this one. 56 */ 57 next = (struct ext2_dir_entry *) (buf + offset + curr_rec_len); 58 if ((offset + (int) curr_rec_len < blocksize - 8) && 59 (next->inode == 0) && 60 (offset + (int) curr_rec_len + (int) next->rec_len <= blocksize)) { 61 curr_rec_len += next->rec_len; 62 ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent); 63 if (ls->err) 64 return DIRENT_ABORT; 65 ret = DIRENT_CHANGED; 66 } 67 68 /* 69 * If the directory entry is used, see if we can split the 70 * directory entry to make room for the new name. If so, 71 * truncate it and return. 72 */ 73 if (dirent->inode) { 74 min_rec_len = EXT2_DIR_REC_LEN(dirent->name_len & 0xFF); 75 if (curr_rec_len < (min_rec_len + rec_len)) 76 return ret; 77 rec_len = curr_rec_len - min_rec_len; 78 ls->err = ext2fs_set_rec_len(ls->fs, min_rec_len, dirent); 79 if (ls->err) 80 return DIRENT_ABORT; 81 next = (struct ext2_dir_entry *) (buf + offset + 82 dirent->rec_len); 83 next->inode = 0; 84 next->name_len = 0; 85 ls->err = ext2fs_set_rec_len(ls->fs, rec_len, next); 86 if (ls->err) 87 return DIRENT_ABORT; 88 return DIRENT_CHANGED; 89 } 90 91 /* 92 * If we get this far, then the directory entry is not used. 93 * See if we can fit the request entry in. If so, do it. 94 */ 95 if (curr_rec_len < rec_len) 96 return ret; 97 dirent->inode = ls->inode; 98 dirent->name_len = ls->namelen; 99 strncpy(dirent->name, ls->name, ls->namelen); 100 if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE) 101 dirent->name_len |= (ls->flags & 0x7) << 8; 102 103 ls->done++; 104 return DIRENT_ABORT|DIRENT_CHANGED; 105 } 106 107 /* 108 * Note: the low 3 bits of the flags field are used as the directory 109 * entry filetype. 110 */ 111 #ifdef __TURBOC__ 112 #pragma argsused 113 #endif 114 errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name, 115 ext2_ino_t ino, int flags) 116 { 117 errcode_t retval; 118 struct link_struct ls; 119 struct ext2_inode inode; 120 121 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 122 123 if (!(fs->flags & EXT2_FLAG_RW)) 124 return EXT2_ET_RO_FILSYS; 125 126 ls.fs = fs; 127 ls.name = name; 128 ls.namelen = name ? strlen(name) : 0; 129 ls.inode = ino; 130 ls.flags = flags; 131 ls.done = 0; 132 ls.sb = fs->super; 133 ls.blocksize = fs->blocksize; 134 ls.err = 0; 135 136 retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY, 137 0, link_proc, &ls); 138 if (retval) 139 return retval; 140 if (ls.err) 141 return ls.err; 142 143 if (!ls.done) 144 return EXT2_ET_DIR_NO_SPACE; 145 146 if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0) 147 return retval; 148 149 if (inode.i_flags & EXT2_INDEX_FL) { 150 inode.i_flags &= ~EXT2_INDEX_FL; 151 if ((retval = ext2fs_write_inode(fs, dir, &inode)) != 0) 152 return retval; 153 } 154 155 return 0; 156 } 157
