+/*
+ * symlink.c
+ *
+ * Code to read and set symbolic links in WIM files.
+ */
+
+/*
+ * Copyright (C) 2012, 2013 Eric Biggers
+ *
+ * This file is part of wimlib, a library for working with WIM files.
+ *
+ * wimlib is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ */
+
#include "dentry.h"
-#include "io.h"
+#include "buffer_io.h"
#include "lookup_table.h"
+#include "sha1.h"
+#include <errno.h>
/*
* Find the symlink target of a symbolic link or junction point in the WIM.
*
- * See http://msdn.microsoft.com/en-us/library/cc232006(v=prot.10).aspx
- * Except the first 8 bytes aren't included in the resource (presumably because
- * we already know the reparse tag from the dentry, and we already know the
- * reparse tag len from the lookup table entry resource length).
+ * See http://msdn.microsoft.com/en-us/library/cc232006(v=prot.10).aspx for a
+ * description of the format of the so-called "reparse point data buffers".
+ *
+ * But, in the WIM format, the first 8 bytes of the reparse point data buffer
+ * are omitted, presumably because we already know the reparse tag from the
+ * dentry, and we already know the reparse tag length from the lookup table
+ * entry resource length.
*/
-static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
- char *buf, size_t buf_len,
- bool is_junction_point)
+static ssize_t
+get_symlink_name(const void *resource, size_t resource_len,
+ void *buf, size_t buf_len,
+ u32 reparse_tag)
{
const u8 *p = resource;
u16 substitute_name_offset;
unsigned header_size;
char *translated_target;
bool is_absolute;
+ u32 flags;
if (resource_len < 12)
return -EIO;
p = get_u16(p, &substitute_name_len);
p = get_u16(p, &print_name_offset);
p = get_u16(p, &print_name_len);
- if (is_junction_point) {
+ get_u32(p, &flags);
+
+ wimlib_assert(reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
+ reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
+
+ if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT) {
header_size = 8;
} else {
- u32 flags;
- p = get_u32(p, &flags);
is_absolute = (flags & 1) ? false : true;
header_size = 12;
+ p += 4;
}
if (header_size + substitute_name_offset + substitute_name_len > resource_len)
return -EIO;
- link_target = utf16_to_utf8(p + substitute_name_offset,
- substitute_name_len,
- &link_target_len);
+
+ ret = utf16_to_utf8((const char *)p + substitute_name_offset,
+ substitute_name_len,
+ &link_target, &link_target_len);
+ if (ret == WIMLIB_ERR_INVALID_UTF16_STRING)
+ return -EILSEQ;
+ else if (ret == WIMLIB_ERR_NOMEM)
+ return -ENOMEM;
+
+ wimlib_assert(ret == 0);
if (!link_target)
return -EIO;
}
translated_target = link_target;
- if (is_junction_point || is_absolute) {
+ if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT || is_absolute) {
if (link_target_len < 7
|| memcmp(translated_target, "\\??\\", 4) != 0
|| translated_target[4] == '\0'
}
translated_target += 4;
link_target_len -= 4;
+ /* There's a drive letter, so just leave the backslashes since
+ * it won't go anyhwere on UNIX anyway...
+ *
+ * XXX
+ * NTFS-3g tries to re-map these links to actually point to
+ * something, so maybe we could do something like that here
+ * XXX*/
+ } else {
+ for (size_t i = 0; i < link_target_len; i++)
+ if (translated_target[i] == '\\')
+ translated_target[i] = '/';
}
- for (size_t i = 0; i < link_target_len; i++)
- if (translated_target[i] == '\\')
- translated_target[i] = '/';
memcpy(buf, translated_target, link_target_len + 1);
ret = link_target_len;
return ret;
}
-void *make_symlink_reparse_data_buf(const char *symlink_target, size_t *len_ret)
+static int
+make_symlink_reparse_data_buf(const mbchar *symlink_target,
+ size_t *len_ret, void **buf_ret)
{
size_t utf8_len = strlen(symlink_target);
+ char *name_utf16;
size_t utf16_len;
- char *name_utf16 = utf8_to_utf16(symlink_target, utf8_len, &utf16_len);
- if (!name_utf16)
- return NULL;
- /*DEBUG("utf16_len = %zu", utf16_len);*/
+ int ret;
+
+ ret = utf8_to_utf16(symlink_target, utf8_len,
+ &name_utf16, &utf16_len);
+ if (ret != 0)
+ return ret;
+
for (size_t i = 0; i < utf16_len / 2; i++)
- if (((u16*)name_utf16)[i] == to_le16('/'))
- ((u16*)name_utf16)[i] = to_le16('\\');
+ if (((u16*)name_utf16)[i] == cpu_to_le16('/'))
+ ((u16*)name_utf16)[i] = cpu_to_le16('\\');
size_t len = 12 + utf16_len * 2;
void *buf = MALLOC(len);
- if (!buf)
- goto out;
-
- u8 *p = buf;
- p = put_u16(p, 0); /* Substitute name offset */
- p = put_u16(p, utf16_len); /* Substitute name length */
- p = put_u16(p, utf16_len); /* Print name offset */
- p = put_u16(p, utf16_len); /* Print name length */
- p = put_u32(p, (symlink_target[0] == '/') ? 0 : 1);
- p = put_bytes(p, utf16_len, name_utf16);
- p = put_bytes(p, utf16_len, name_utf16);
- /*DEBUG("utf16_len = %zu, len = %zu", utf16_len, len);*/
- *len_ret = len;
-out:
+ if (buf) {
+ u8 *p = buf;
+ p = put_u16(p, utf16_len); /* Substitute name offset */
+ p = put_u16(p, utf16_len); /* Substitute name length */
+ p = put_u16(p, 0); /* Print name offset */
+ p = put_u16(p, utf16_len); /* Print name length */
+ p = put_u32(p, 1); /* flags: 0 iff *full* target, including drive letter??? */
+ p = put_bytes(p, utf16_len, (const u8*)name_utf16);
+ p = put_bytes(p, utf16_len, (const u8*)name_utf16);
+ *len_ret = len;
+ *buf_ret = buf;
+ ret = 0;
+ } else {
+ ret = WIMLIB_ERR_NOMEM;
+ }
FREE(name_utf16);
- return buf;
+ return ret;
}
-/* Get the symlink target from a dentry that's already checked to be either a
- * "real" symlink or a junction point. */
-ssize_t dentry_readlink(const struct dentry *dentry, char *buf, size_t buf_len,
- const WIMStruct *w)
+/* Get the symlink target from a WIM inode.
+ *
+ * The inode may be either a "real" symlink (reparse tag
+ * WIM_IO_REPARSE_TAG_SYMLINK), or it may be a junction point (reparse tag
+ * WIM_IO_REPARSE_TAG_MOUNT_POINT).
+ */
+ssize_t
+inode_readlink(const struct wim_inode *inode, mbchar *buf, size_t buf_len,
+ const WIMStruct *w, int read_resource_flags)
{
- struct ads_entry *ads;
- struct lookup_table_entry *entry;
- struct resource_entry *res_entry;
- bool is_junction_point;
-
- wimlib_assert(dentry_is_symlink(dentry));
-
- if (dentry->reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK) {
- is_junction_point = false;
- /*
- * This is of course not actually documented, but what I think is going
- * on here is that the symlink dentries have 2 alternate data streams;
- * one is the default data stream, which is not used and is empty, and
- * one is the symlink buffer data stream, which is confusingly also
- * unnamed, but isn't empty as it contains the symlink target within the
- * resource.
- */
- if (dentry->num_ads != 2)
- return -EIO;
- if ((entry = __lookup_resource(w->lookup_table, dentry->ads_entries[0].hash)))
- goto do_readlink;
- if ((entry = __lookup_resource(w->lookup_table, dentry->ads_entries[1].hash)))
- goto do_readlink;
- } else {
- wimlib_assert(dentry->reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
+ const struct wim_lookup_table_entry *lte;
+ int ret;
- is_junction_point = true;
+ wimlib_assert(inode_is_symlink(inode));
- if ((entry = __lookup_resource(w->lookup_table, dentry->hash)))
- goto do_readlink;
- }
- return -EIO;
-do_readlink:
- res_entry = &entry->resource_entry;
- if (res_entry->original_size > 10000)
+ lte = inode_unnamed_lte(inode, w->lookup_table);
+ if (!lte)
return -EIO;
- char res_buf[res_entry->original_size];
- if (read_full_resource(w->fp, res_entry->size,
- res_entry->original_size,
- res_entry->offset,
- wim_resource_compression_type(w, res_entry),
- res_buf) != 0)
+
+ if (wim_resource_size(lte) > 10000)
return -EIO;
- return get_symlink_name(res_buf, res_entry->original_size, buf,
- buf_len, is_junction_point);
+
+ u8 res_buf[wim_resource_size(lte)];
+ ret = read_full_wim_resource(lte, res_buf, read_resource_flags);
+ if (ret != 0)
+ return -EIO;
+ return get_symlink_name(res_buf, wim_resource_size(lte), buf,
+ buf_len, inode->i_reparse_tag);
+}
+
+/*
+ * Sets @inode to be a symbolic link pointing to @target.
+ *
+ * A lookup table entry for the symbolic link data buffer is created and
+ * inserted into @lookup_table, unless there is an existing lookup table entry
+ * for the exact same data, in which its reference count is incremented.
+ *
+ * The lookup table entry is returned in @lte_ret.
+ *
+ * On failure @dentry and @lookup_table are not modified.
+ */
+int
+inode_set_symlink(struct wim_inode *inode,
+ const mbchar *target,
+ struct wim_lookup_table *lookup_table,
+ struct wim_lookup_table_entry **lte_ret)
+
+{
+ int ret;
+ size_t symlink_buf_len;
+ struct wim_lookup_table_entry *lte = NULL, *existing_lte;
+ u8 symlink_buf_hash[SHA1_HASH_SIZE];
+ void *symlink_buf;
+
+ ret = make_symlink_reparse_data_buf(target, &symlink_buf_len,
+ &symlink_buf);
+ if (ret != 0)
+ return ret;
+
+ DEBUG("Made symlink reparse data buf (len = %zu, name len = %zu)",
+ symlink_buf_len, symlink_buf_len);
+
+ sha1_buffer(symlink_buf, symlink_buf_len, symlink_buf_hash);
+
+ existing_lte = __lookup_resource(lookup_table, symlink_buf_hash);
+
+ if (existing_lte) {
+ lte = existing_lte;
+ FREE(symlink_buf);
+ symlink_buf = NULL;
+ } else {
+ DEBUG("Creating new lookup table entry for symlink buf");
+ lte = new_lookup_table_entry();
+ if (!lte) {
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_symlink_buf;
+ }
+ lte->resource_location = RESOURCE_IN_ATTACHED_BUFFER;
+ lte->attached_buffer = symlink_buf;
+ lte->resource_entry.original_size = symlink_buf_len;
+ lte->resource_entry.size = symlink_buf_len;
+ copy_hash(lte->hash, symlink_buf_hash);
+ }
+
+ inode->i_lte = lte;
+ inode->i_resolved = 1;
+
+ DEBUG("Loaded symlink buf");
+
+ if (existing_lte)
+ lte->refcnt++;
+ else
+ lookup_table_insert(lookup_table, lte);
+ if (lte_ret)
+ *lte_ret = lte;
+ return 0;
+out_free_symlink_buf:
+ FREE(symlink_buf);
+ return ret;
}
git://wimlib.net / wimlib / blobdiff