[821] | 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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