3 #include "lookup_table.h"
8 * Find the symlink target of a symbolic link or junction point in the WIM.
10 * See http://msdn.microsoft.com/en-us/library/cc232006(v=prot.10).aspx
11 * Except the first 8 bytes aren't included in the resource (presumably because
12 * we already know the reparse tag from the dentry, and we already know the
13 * reparse tag len from the lookup table entry resource length).
15 static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
16 char *buf, size_t buf_len,
19 const u8 *p = resource;
20 u16 substitute_name_offset;
21 u16 substitute_name_len;
22 u16 print_name_offset;
25 size_t link_target_len;
28 char *translated_target;
32 if (resource_len < 12)
34 p = get_u16(p, &substitute_name_offset);
35 p = get_u16(p, &substitute_name_len);
36 p = get_u16(p, &print_name_offset);
37 p = get_u16(p, &print_name_len);
40 wimlib_assert(reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
41 reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
43 /* I think that some junction points incorrectly get marked as symbolic
44 * links. So, parse the link buffer as a symlink if the flags seem
47 reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
49 if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT) {
52 is_absolute = (flags & 1) ? false : true;
56 if (header_size + substitute_name_offset + substitute_name_len > resource_len)
58 link_target = utf16_to_utf8(p + substitute_name_offset,
65 if (link_target_len + 1 > buf_len) {
70 translated_target = link_target;
71 if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT || is_absolute) {
72 if (link_target_len < 7
73 || memcmp(translated_target, "\\??\\", 4) != 0
74 || translated_target[4] == '\0'
75 || translated_target[5] != ':'
76 || translated_target[6] != '\\') {
80 translated_target += 4;
82 /* There's a drive letter, so just leave the backslashes since
83 * it won't go anyhwere on UNIX anyway... */
85 for (size_t i = 0; i < link_target_len; i++)
86 if (translated_target[i] == '\\')
87 translated_target[i] = '/';
90 memcpy(buf, translated_target, link_target_len + 1);
91 ret = link_target_len;
97 void *make_symlink_reparse_data_buf(const char *symlink_target, size_t *len_ret)
99 size_t utf8_len = strlen(symlink_target);
101 char *name_utf16 = utf8_to_utf16(symlink_target, utf8_len, &utf16_len);
104 /*DEBUG("utf16_len = %zu", utf16_len);*/
105 for (size_t i = 0; i < utf16_len / 2; i++)
106 if (((u16*)name_utf16)[i] == to_le16('/'))
107 ((u16*)name_utf16)[i] = to_le16('\\');
108 size_t len = 12 + utf16_len * 2;
109 void *buf = MALLOC(len);
112 /* XXX Fix absolute paths */
115 p = put_u16(p, 0); /* Substitute name offset */
116 p = put_u16(p, utf16_len); /* Substitute name length */
117 p = put_u16(p, utf16_len); /* Print name offset */
118 p = put_u16(p, utf16_len); /* Print name length */
120 p = put_bytes(p, utf16_len, name_utf16);
121 p = put_bytes(p, utf16_len, name_utf16);
122 /*DEBUG("utf16_len = %zu, len = %zu", utf16_len, len);*/
129 static const struct lookup_table_entry *
130 dentry_first_lte(const struct dentry *dentry, const struct lookup_table *table)
132 const struct lookup_table_entry *lte;
133 if (dentry->resolved) {
136 for (u16 i = 0; i < dentry->num_ads; i++)
137 if (dentry->ads_entries[i].lte)
138 return dentry->ads_entries[i].lte;
140 const u8 *hash = dentry->hash;
143 if ((lte = __lookup_resource(table, hash)))
145 if (i == dentry->num_ads)
147 hash = dentry->ads_entries[i].hash;
154 /* Get the symlink target from a dentry that's already checked to be either a
155 * "real" symlink or a junction point. */
156 ssize_t dentry_readlink(const struct dentry *dentry, char *buf, size_t buf_len,
159 const struct resource_entry *res_entry;
160 const struct lookup_table_entry *lte;
162 wimlib_assert(dentry_is_symlink(dentry));
164 lte = dentry_first_lte(dentry, w->lookup_table);
168 res_entry = <e->resource_entry;
169 if (res_entry->original_size > 10000)
172 char __res_buf[res_entry->original_size];
174 if (lte->is_symlink && lte->symlink_buf) {
175 res_buf = lte->symlink_buf;
178 if (read_full_resource(w->fp, res_entry->size,
179 res_entry->original_size,
181 wim_resource_compression_type(w, res_entry),
186 return get_symlink_name(res_buf, res_entry->original_size, buf,
187 buf_len, dentry->reparse_tag);
190 static int dentry_set_symlink_buf(struct dentry *dentry,
191 const u8 symlink_buf_hash[])
193 struct ads_entry *ads_entries;
195 ads_entries = CALLOC(2, sizeof(struct ads_entry));
197 return WIMLIB_ERR_NOMEM;
198 memcpy(ads_entries[1].hash, symlink_buf_hash, WIM_HASH_SIZE);
199 dentry_free_ads_entries(dentry);
201 dentry->ads_entries = ads_entries;
205 int dentry_set_symlink(struct dentry *dentry, const char *target,
206 struct lookup_table *lookup_table,
207 struct lookup_table_entry **lte_ret)
211 size_t symlink_buf_len;
212 struct lookup_table_entry *lte = NULL, *existing_lte;
213 u8 symlink_buf_hash[WIM_HASH_SIZE];
216 symlink_buf = make_symlink_reparse_data_buf(target, &symlink_buf_len);
218 return WIMLIB_ERR_NOMEM;
220 DEBUG("Made symlink reparse data buf (len = %zu, name len = %zu)",
221 symlink_buf_len, ret);
223 sha1_buffer(symlink_buf, symlink_buf_len, symlink_buf_hash);
225 existing_lte = __lookup_resource(lookup_table, symlink_buf_hash);
228 existing_lte->refcnt++;
230 DEBUG("Creating new lookup table entry for symlink buf");
231 lte = new_lookup_table_entry();
233 ret = WIMLIB_ERR_NOMEM;
234 goto out_free_symlink_buf;
236 lte->is_symlink = true;
237 lte->symlink_buf = symlink_buf;
238 lte->resource_entry.original_size = symlink_buf_len;
239 lte->resource_entry.size = symlink_buf_len;
240 memcpy(lte->hash, symlink_buf_hash, WIM_HASH_SIZE);
243 ret = dentry_set_symlink_buf(dentry, symlink_buf_hash);
248 DEBUG("Loaded symlink buf");
251 lookup_table_insert(lookup_table, lte);
257 out_free_symlink_buf: