link_target_len >= 3 &&
translated_target[0] != '\0' &&
translated_target[1] == ':' &&
- translated_target[2] == '/')
+ translated_target[2] == '\\')
{
/* "Absolute" symlink, with drive letter */
translated_target += 2;
} else if (reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK &&
link_target_len >= 1)
{
- if (translated_target[0] == '/')
+ if (translated_target[0] == '\\')
/* "Absolute" symlink, without drive letter */
;
else
return ret;
}
+#define SYMBOLIC_LINK_RELATIVE 0x00000001
+
+/* Given a UNIX symlink target, prepare the corresponding symbolic link reparse
+ * data buffer. */
static int
make_symlink_reparse_data_buf(const char *symlink_target,
size_t *len_ret, void **buf_ret)
{
+ int ret;
utf16lechar *name_utf16le;
size_t name_utf16le_nbytes;
- int ret;
+ size_t substitute_name_nbytes;
+ size_t print_name_nbytes;
+ static const char abs_subst_name_prefix[12] = "\\\0?\0?\0\\\0C\0:\0";
+ static const char abs_print_name_prefix[4] = "C\0:\0";
+ u32 flags;
+ size_t len;
+ void *buf;
+ void *p;
ret = tstr_to_utf16le(symlink_target, strlen(symlink_target),
&name_utf16le, &name_utf16le_nbytes);
if (name_utf16le[i] == cpu_to_le16('/'))
name_utf16le[i] = cpu_to_le16('\\');
- size_t len = 12 + (name_utf16le_nbytes + 2) * 2;
- void *buf = MALLOC(len);
- if (buf) {
- void *p = buf;
- p = put_u16(p, 0); /* Substitute name offset */
- p = put_u16(p, name_utf16le_nbytes); /* Substitute name length */
- p = put_u16(p, name_utf16le_nbytes + 2); /* Print name offset */
- p = put_u16(p, name_utf16le_nbytes); /* Print name length */
- p = put_u32(p, 1); /* flags: 0 if relative link, otherwise 1 */
- p = put_bytes(p, name_utf16le_nbytes, name_utf16le);
- p = put_u16(p, 0);
- p = put_bytes(p, name_utf16le_nbytes, name_utf16le);
- p = put_u16(p, 0);
- *len_ret = len;
- *buf_ret = buf;
- ret = 0;
- } else {
+ /* Compatability notes:
+ *
+ * On UNIX, an absolute symbolic link begins with '/'; everything else
+ * is a relative symbolic link. (Quite simple compared to the various
+ * ways to provide Windows paths.)
+ *
+ * To change a UNIX relative symbolic link to Windows format, we only
+ * need to translate it to UTF-16LE and replace backslashes with forward
+ * slashes. We do not make any attempt to handle filename character
+ * problems, such as a link target that itself contains backslashes on
+ * UNIX. Then, for these relative links, we set the reparse header
+ * @flags field to SYMBOLIC_LINK_RELATIVE.
+ *
+ * For UNIX absolute symbolic links, we must set the @flags field to 0.
+ * Then, there are multiple options as to actually represent the
+ * absolute link targets:
+ *
+ * (1) An absolute path beginning with one backslash character. similar
+ * to UNIX-style, just with a different path separator. Print name same
+ * as substitute name.
+ *
+ * (2) Absolute path beginning with drive letter followed by a
+ * backslash. Print name same as substitute name.
+ *
+ * (3) Absolute path beginning with drive letter followed by a
+ * backslash; substitute name prefixed with \??\, otherwise same as
+ * print name.
+ *
+ * We choose option (3) here, and we just assume C: for the drive
+ * letter. The reasoning for this is:
+ *
+ * (1) Microsoft imagex.exe has a bug where it does not attempt to do
+ * reparse point fixups for these links, even though they are valid
+ * absolute links. (Note: in this case prefixing the substitute name
+ * with \??\ does not work; it just makes the data unable to be restored
+ * at all.)
+ * (2) Microsoft imagex.exe will fail when doing reparse point fixups
+ * for these. It apparently contains a bug that causes it to create an
+ * invalid reparse point, which then cannot be restored.
+ * (3) This is the only option I tested for which reparse point fixups
+ * worked properly in Microsoft imagex.exe.
+ *
+ * So option (3) it is.
+ */
+
+ substitute_name_nbytes = name_utf16le_nbytes;
+ print_name_nbytes = name_utf16le_nbytes;
+ if (symlink_target[0] == '/') {
+ substitute_name_nbytes += sizeof(abs_subst_name_prefix);
+ print_name_nbytes += sizeof(abs_print_name_prefix);
+ }
+
+ len = 12 + substitute_name_nbytes + print_name_nbytes +
+ 2 * sizeof(utf16lechar);
+ buf = MALLOC(len);
+
+ if (!buf) {
ret = WIMLIB_ERR_NOMEM;
+ goto out_free_name_utf16le;
}
+
+ p = buf;
+
+ /* Substitute name offset */
+ p = put_u16(p, 0);
+
+ /* Substitute name length */
+ p = put_u16(p, substitute_name_nbytes);
+
+ /* Print name offset */
+ p = put_u16(p, substitute_name_nbytes + sizeof(utf16lechar));
+
+ /* Print name length */
+ p = put_u16(p, print_name_nbytes);
+
+ /* Flags */
+ flags = 0;
+ if (symlink_target[0] != '/')
+ flags |= SYMBOLIC_LINK_RELATIVE;
+ p = put_u32(p, flags);
+
+ /* Substitute name */
+ if (symlink_target[0] == '/')
+ p = put_bytes(p, sizeof(abs_subst_name_prefix), abs_subst_name_prefix);
+ p = put_bytes(p, name_utf16le_nbytes, name_utf16le);
+ p = put_u16(p, 0);
+
+ /* Print name */
+ if (symlink_target[0] == '/')
+ p = put_bytes(p, sizeof(abs_print_name_prefix), abs_print_name_prefix);
+ p = put_bytes(p, name_utf16le_nbytes, name_utf16le);
+ p = put_u16(p, 0);
+
+ *len_ret = len;
+ *buf_ret = buf;
+ ret = 0;
+out_free_name_utf16le:
FREE(name_utf16le);
return ret;
}
git://wimlib.net / wimlib / blobdiff