#include <sys/stat.h>
+#ifdef HAVE_ALLOCA_H
+# include <alloca.h>
+#endif
+
/*
* Find the symlink target of a symbolic link or junction point in the WIM.
*
header_size = 12;
p += 4;
}
- if (header_size + substitute_name_offset + substitute_name_len > resource_len)
+ if (header_size +
+ substitute_name_offset + substitute_name_len > resource_len)
return -EIO;
ret = utf16le_to_tstr((const utf16lechar*)(p + substitute_name_offset),
if (ret)
return -errno;
- if (link_target_len + 1 > buf_len) {
- ret = -ENAMETOOLONG;
- goto out;
- }
-
DEBUG("Interpeting substitute name \"%s\" (ReparseTag=0x%x)",
link_target, reparse_tag);
translate_slashes = true;
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
/* "Relative" symlink, without drive letter */
;
} else {
- ERROR("Invalid reparse point: \"%s\"", translated_target);
+ ERROR("Invalid reparse point substitute name: \"%s\"", translated_target);
ret = -EIO;
goto out;
}
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;
+
+ if (link_target_len > buf_len) {
+ link_target_len = buf_len;
+ ret = -ENAMETOOLONG;
+ } else {
+ ret = link_target_len;
+ }
+ memcpy(buf, translated_target, link_target_len);
out:
FREE(link_target);
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;
}
{
const struct wim_lookup_table_entry *lte;
int ret;
+ u8 *res_buf;
wimlib_assert(inode_is_symlink(inode));
if (wim_resource_size(lte) > REPARSE_POINT_MAX_SIZE)
return -EIO;
- u8 res_buf[wim_resource_size(lte)];
+ res_buf = alloca(wim_resource_size(lte));
ret = read_full_resource_into_buf(lte, res_buf, threadsafe);
if (ret)
return -EIO;
- return get_symlink_name(res_buf, wim_resource_size(lte), buf,
- buf_len, inode->i_reparse_tag);
+ return get_symlink_name(res_buf, wim_resource_size(lte),
+ buf, buf_len, inode->i_reparse_tag);
}
/*
# define os_get_ino_and_dev unix_get_ino_and_dev
#endif
-/* Fix up reparse points--- mostly shared between UNIX and Windows */
+/* Fix up absolute symbolic link targets--- mostly shared between UNIX and
+ * Windows */
tchar *
fixup_symlink(tchar *dest, u64 capture_root_ino, u64 capture_root_dev)
{
ret = os_get_ino_and_dev(dest, &ino, &dev);
*p = save;
+ if (ret) /* stat() failed before we got to the capture root---
+ assume the link points outside it. */
+ return NULL;
+
if (ino == capture_root_ino && dev == capture_root_dev) {
/* Link points inside capture root. Return abbreviated
* path. */
git://wimlib.net / wimlib / blobdiff