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