3 #include "lookup_table.h"
7 * Find the symlink target of a symbolic link or junction point in the WIM.
9 * See http://msdn.microsoft.com/en-us/library/cc232006(v=prot.10).aspx
10 * Except the first 8 bytes aren't included in the resource (presumably because
11 * we already know the reparse tag from the dentry, and we already know the
12 * reparse tag len from the lookup table entry resource length).
14 static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
15 char *buf, size_t buf_len,
18 const u8 *p = resource;
19 u16 substitute_name_offset;
20 u16 substitute_name_len;
21 u16 print_name_offset;
24 size_t link_target_len;
27 char *translated_target;
31 if (resource_len < 12)
33 p = get_u16(p, &substitute_name_offset);
34 p = get_u16(p, &substitute_name_len);
35 p = get_u16(p, &print_name_offset);
36 p = get_u16(p, &print_name_len);
39 wimlib_assert(reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
40 reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
42 /* I think that some junction points incorrectly get marked as symbolic
43 * links. So, parse the link buffer as a symlink if the flags seem
46 reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
48 if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT) {
51 is_absolute = (flags & 1) ? false : true;
55 if (header_size + substitute_name_offset + substitute_name_len > resource_len)
57 link_target = utf16_to_utf8(p + substitute_name_offset,
64 if (link_target_len + 1 > buf_len) {
69 translated_target = link_target;
70 if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT || is_absolute) {
71 if (link_target_len < 7
72 || memcmp(translated_target, "\\??\\", 4) != 0
73 || translated_target[4] == '\0'
74 || translated_target[5] != ':'
75 || translated_target[6] != '\\') {
79 translated_target += 4;
81 /* There's a drive letter, so just leave the backslashes since
82 * it won't go anyhwere on UNIX anyway... */
84 for (size_t i = 0; i < link_target_len; i++)
85 if (translated_target[i] == '\\')
86 translated_target[i] = '/';
89 memcpy(buf, translated_target, link_target_len + 1);
90 ret = link_target_len;
96 void *make_symlink_reparse_data_buf(const char *symlink_target, size_t *len_ret)
98 size_t utf8_len = strlen(symlink_target);
100 char *name_utf16 = utf8_to_utf16(symlink_target, utf8_len, &utf16_len);
103 /*DEBUG("utf16_len = %zu", utf16_len);*/
104 for (size_t i = 0; i < utf16_len / 2; i++)
105 if (((u16*)name_utf16)[i] == to_le16('/'))
106 ((u16*)name_utf16)[i] = to_le16('\\');
107 size_t len = 12 + utf16_len * 2;
108 void *buf = MALLOC(len);
111 /* XXX Fix absolute paths */
114 p = put_u16(p, 0); /* Substitute name offset */
115 p = put_u16(p, utf16_len); /* Substitute name length */
116 p = put_u16(p, utf16_len); /* Print name offset */
117 p = put_u16(p, utf16_len); /* Print name length */
119 p = put_bytes(p, utf16_len, name_utf16);
120 p = put_bytes(p, utf16_len, name_utf16);
121 /*DEBUG("utf16_len = %zu, len = %zu", utf16_len, len);*/
128 /* Get the symlink target from a dentry that's already checked to be either a
129 * "real" symlink or a junction point. */
130 ssize_t dentry_readlink(const struct dentry *dentry, char *buf, size_t buf_len,
133 struct resource_entry *res_entry;
134 struct lookup_table_entry *lte;
136 const u8 *hash = dentry->hash;
138 wimlib_assert(dentry_is_symlink(dentry));
141 if ((lte = __lookup_resource(w->lookup_table, hash)))
143 if (i == dentry->num_ads)
145 hash = dentry->ads_entries[i].hash;
148 res_entry = <e->resource_entry;
149 if (res_entry->original_size > 10000)
152 char __res_buf[res_entry->original_size];
154 if (lte->is_symlink && lte->symlink_buf) {
155 res_buf = lte->symlink_buf;
158 if (read_full_resource(w->fp, res_entry->size,
159 res_entry->original_size,
161 wim_resource_compression_type(w, res_entry),
166 return get_symlink_name(res_buf, res_entry->original_size, buf,
167 buf_len, dentry->reparse_tag);
170 static int dentry_set_symlink_buf(struct dentry *dentry,
171 const u8 symlink_buf_hash[])
173 struct ads_entry *ads_entries;
175 ads_entries = CALLOC(2, sizeof(struct ads_entry));
177 return WIMLIB_ERR_NOMEM;
178 memcpy(ads_entries[1].hash, symlink_buf_hash, WIM_HASH_SIZE);
179 dentry_free_ads_entries(dentry);
181 dentry->ads_entries = ads_entries;
185 int dentry_set_symlink(struct dentry *dentry, const char *target,
186 struct lookup_table *lookup_table)
190 size_t symlink_buf_len;
191 struct lookup_table_entry *lte = NULL, *existing_lte;
192 u8 symlink_buf_hash[WIM_HASH_SIZE];
195 symlink_buf = make_symlink_reparse_data_buf(target, &symlink_buf_len);
197 return WIMLIB_ERR_NOMEM;
199 DEBUG("Made symlink reparse data buf (len = %zu, name len = %zu)",
200 symlink_buf_len, ret);
202 sha1_buffer(symlink_buf, symlink_buf_len, symlink_buf_hash);
204 existing_lte = __lookup_resource(lookup_table, symlink_buf_hash);
207 existing_lte->refcnt++;
209 DEBUG("Creating new lookup table entry for symlink buf");
210 lte = new_lookup_table_entry();
212 ret = WIMLIB_ERR_NOMEM;
213 goto out_free_symlink_buf;
215 lte->is_symlink = true;
216 lte->symlink_buf = symlink_buf;
217 lte->resource_entry.original_size = symlink_buf_len;
218 lte->resource_entry.size = symlink_buf_len;
219 memcpy(lte->hash, symlink_buf_hash, WIM_HASH_SIZE);
222 ret = dentry_set_symlink_buf(dentry, symlink_buf_hash);
227 DEBUG("Loaded symlink buf");
230 lookup_table_insert(lookup_table, lte);
234 out_free_symlink_buf: