*/
/*
- * Copyright (C) 2012 Eric Biggers
+ * Copyright (C) 2012, 2013 Eric Biggers
*
* This file is part of wimlib, a library for working with WIM files.
*
#include "sha1.h"
#include <errno.h>
+/* UNIX version of getting and setting the data in reparse points */
+#if !defined(__WIN32__)
+
+#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.
*
- * 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,
- u32 reparse_tag)
+static ssize_t
+get_symlink_name(const void *resource, size_t resource_len, char *buf,
+ size_t buf_len, u32 reparse_tag)
{
- const u8 *p = resource;
+ const void *p = resource;
u16 substitute_name_offset;
u16 substitute_name_len;
u16 print_name_offset;
u16 print_name_len;
char *link_target;
+ char *translated_target;
size_t link_target_len;
ssize_t ret;
unsigned header_size;
- char *translated_target;
- bool is_absolute;
- u32 flags;
+ bool translate_slashes;
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);
- get_u32(p, &flags);
wimlib_assert(reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
- /* I think that some junction points incorrectly get marked as symbolic
- * links. So, parse the link buffer as a symlink if the flags seem
- * plausible. */
- if (flags <= 1)
- reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
-
- if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT) {
+ if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT)
header_size = 8;
- } else {
- is_absolute = (flags & 1) ? false : true;
+ else {
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 = 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;
+ ret = utf16le_to_tstr((const utf16lechar*)(p + substitute_name_offset),
+ substitute_name_len,
+ &link_target, &link_target_len);
+ if (ret)
+ return -errno;
- wimlib_assert(ret == 0);
-
- if (!link_target)
- return -EIO;
-
- if (link_target_len + 1 > buf_len) {
- ret = -ENAMETOOLONG;
+ DEBUG("Interpeting substitute name \"%s\" (ReparseTag=0x%x)",
+ link_target, reparse_tag);
+ translate_slashes = true;
+ translated_target = link_target;
+ if (link_target_len >= 7 &&
+ translated_target[0] == '\\' &&
+ translated_target[1] == '?' &&
+ translated_target[2] == '?' &&
+ translated_target[3] == '\\' &&
+ translated_target[4] != '\0' &&
+ translated_target[5] == ':' &&
+ translated_target[6] == '\\')
+ {
+ /* "Full" symlink or junction (\??\x:\ prefixed path) */
+ translated_target += 6;
+ link_target_len -= 6;
+ } else if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT &&
+ link_target_len >= 12 &&
+ memcmp(translated_target, "\\\\?\\Volume{", 11) == 0 &&
+ translated_target[link_target_len - 1] == '\\')
+ {
+ /* Volume junction. Can't really do anything with it. */
+ translate_slashes = false;
+ } else if (reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK &&
+ link_target_len >= 3 &&
+ translated_target[0] != '\0' &&
+ translated_target[1] == ':' &&
+ translated_target[2] == '\\')
+ {
+ /* "Absolute" symlink, with drive letter */
+ translated_target += 2;
+ link_target_len -= 2;
+ } else if (reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK &&
+ link_target_len >= 1)
+ {
+ if (translated_target[0] == '\\')
+ /* "Absolute" symlink, without drive letter */
+ ;
+ else
+ /* "Relative" symlink, without drive letter */
+ ;
+ } else {
+ ERROR("Invalid reparse point substitute name: \"%s\"", translated_target);
+ ret = -EIO;
goto out;
}
- translated_target = link_target;
- 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[5] != ':'
- || translated_target[6] != '\\') {
- ret = -EIO;
- goto out;
- }
- 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 {
+ if (translate_slashes)
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;
}
-static int make_symlink_reparse_data_buf(const char *symlink_target,
- size_t *len_ret, void **buf_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, void *rpdata,
+ size_t *rplen_ret)
{
- size_t utf8_len = strlen(symlink_target);
- char *name_utf16;
- size_t utf16_len;
int ret;
+ utf16lechar *name_utf16le;
+ size_t name_utf16le_nbytes;
+ 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 rplen;
+ void *p;
- ret = utf8_to_utf16(symlink_target, utf8_len,
- &name_utf16, &utf16_len);
- if (ret != 0)
+ ret = tstr_to_utf16le(symlink_target, strlen(symlink_target),
+ &name_utf16le, &name_utf16le_nbytes);
+ if (ret)
return ret;
- for (size_t i = 0; i < utf16_len / 2; i++)
- 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) {
- 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;
+ for (size_t i = 0; i < name_utf16le_nbytes / 2; i++)
+ if (name_utf16le[i] == cpu_to_le16('/'))
+ name_utf16le[i] = cpu_to_le16('\\');
+
+ /* 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);
+ }
+
+ rplen = 12 + substitute_name_nbytes + print_name_nbytes +
+ 2 * sizeof(utf16lechar);
+
+ if (rplen > REPARSE_POINT_MAX_SIZE) {
+ ERROR("Symlink \"%s\" is too long!", symlink_target);
+ return WIMLIB_ERR_LINK;
}
- FREE(name_utf16);
+
+ p = rpdata;
+
+ /* 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);
+
+ *rplen_ret = rplen;
+ ret = 0;
+out_free_name_utf16le:
+ FREE(name_utf16le);
return ret;
}
-/* Get the symlink target from a dentry.
+/* Get the symlink target from a WIM inode.
*
- * The dentry may be either "real" symlink or a junction point.
+ * 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 inode *inode, char *buf, size_t buf_len,
- const WIMStruct *w, int read_resource_flags)
+ssize_t
+inode_readlink(const struct wim_inode *inode, char *buf, size_t buf_len,
+ const WIMStruct *w, bool threadsafe)
{
- const struct lookup_table_entry *lte;
+ const struct wim_lookup_table_entry *lte;
int ret;
+ u8 *res_buf;
wimlib_assert(inode_is_symlink(inode));
if (!lte)
return -EIO;
- if (wim_resource_size(lte) > 10000)
+ if (wim_resource_size(lte) > REPARSE_POINT_MAX_SIZE)
return -EIO;
- u8 res_buf[wim_resource_size(lte)];
- ret = read_full_wim_resource(lte, res_buf, read_resource_flags);
- if (ret != 0)
+ 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->reparse_tag);
+ return get_symlink_name(res_buf, wim_resource_size(lte),
+ buf, buf_len, inode->i_reparse_tag);
}
/*
*
* On failure @dentry and @lookup_table are not modified.
*/
-int inode_set_symlink(struct inode *inode, const char *target,
- struct lookup_table *lookup_table,
- struct lookup_table_entry **lte_ret)
+int
+inode_set_symlink(struct wim_inode *inode,
+ const char *target,
+ struct wim_lookup_table *lookup_table,
+ struct wim_lookup_table_entry **lte_ret)
{
int ret;
- size_t symlink_buf_len;
- struct 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);
+ /* Buffer for reparse point data */
+ u8 rpdata[REPARSE_POINT_MAX_SIZE];
+
+ /* Actual length of the reparse point data (to be calculated by
+ * make_symlink_reparse_data_buf()) */
+ size_t rplen;
- sha1_buffer(symlink_buf, symlink_buf_len, symlink_buf_hash);
+ DEBUG("Creating reparse point data buffer "
+ "for UNIX symlink target \"%s\"", target);
- existing_lte = __lookup_resource(lookup_table, symlink_buf_hash);
+ ret = make_symlink_reparse_data_buf(target, rpdata, &rplen);
+ if (ret)
+ return ret;
+
+ ret = inode_set_unnamed_stream(inode, rpdata, rplen, lookup_table);
+ if (ret)
+ return ret;
+
+ if (lte_ret)
+ *lte_ret = inode->i_lte;
+ return 0;
+}
- if (existing_lte) {
- lte = existing_lte;
- FREE(symlink_buf);
- symlink_buf = NULL;
+static int
+unix_get_ino_and_dev(const char *path, u64 *ino_ret, u64 *dev_ret)
+{
+ struct stat stbuf;
+ if (stat(path, &stbuf)) {
+ WARNING_WITH_ERRNO("Failed to stat \"%s\"", path);
+ /* Treat as a link pointing outside the capture root (it
+ * most likely is). */
+ return WIMLIB_ERR_STAT;
} 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);
+ *ino_ret = stbuf.st_ino;
+ *dev_ret = stbuf.st_dev;
+ return 0;
}
+}
- inode->lte = lte;
- inode->resolved = true;
+#endif /* !defined(__WIN32__) */
- DEBUG("Loaded symlink buf");
+#ifdef __WIN32__
+# include "win32.h"
+# define RP_PATH_SEPARATOR L'\\'
+# define is_rp_path_separator(c) ((c) == L'\\' || (c) == L'/')
+# define os_get_ino_and_dev win32_get_file_and_vol_ids
+#else
+# define RP_PATH_SEPARATOR '/'
+# define is_rp_path_separator(c) ((c) == '/')
+# define os_get_ino_and_dev unix_get_ino_and_dev
+#endif
- 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;
+/* 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)
+{
+ tchar *p = dest;
+
+ DEBUG("Fixing symlink or junction \"%"TS"\"", dest);
+ for (;;) {
+ tchar save;
+ int ret;
+ u64 ino;
+ u64 dev;
+
+ while (is_rp_path_separator(*p))
+ p++;
+
+ save = *p;
+ *p = T('\0');
+ 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. */
+ if (*p == T('\0'))
+ *(p - 1) = RP_PATH_SEPARATOR;
+ while (p - 1 >= dest && is_rp_path_separator(*(p - 1)))
+ p--;
+ return p;
+ }
+
+ if (*p == T('\0')) {
+ /* Link points outside capture root. */
+ return NULL;
+ }
+
+ do {
+ p++;
+ } while (!is_rp_path_separator(*p) && *p != T('\0'));
+ }
}
git://wimlib.net / wimlib / blobdiff