server: Rewrite absolute reparse point targets if the prefix location changes.

server/fd.c

@@ -1906,23 +1906,16 @@ void get_nt_name( struct fd *fd, struct unicode_str *name )
     name->len = fd->nt_namelen;
 }
 
-int check_symlink( char *name )
+static char *decode_symlink(const char *name, ULONG *tag, int *is_dir)
 {
-    struct stat st;
-
-    lstat( name, &st );
-    return S_ISLNK( st.st_mode );
-}
-
-static void decode_symlink(char *name, int *is_dir)
-{
-    char link[MAX_PATH], *p;
+    static char link[MAX_PATH];
     ULONG reparse_tag;
     int len, i;
+    char *p;
 
     len = readlink( name, link, sizeof(link) );
     if (len == -1)
-        return;
+        return NULL;
     link[len] = 0;
     p = link;
     /* skip past relative/absolute indication */
@@ -1930,7 +1923,7 @@ static void decode_symlink(char *name, int *is_dir)
         p++;
     if (*p++ != '/')
     {
-        return;
+        return NULL;
     }
     /* decode the reparse tag */
     reparse_tag = 0;
@@ -1944,7 +1937,7 @@ static void decode_symlink(char *name, int *is_dir)
         else if (c == '.' && *p++ == '/')
             val = 1;
         else
-            return;
+            return NULL;
         reparse_tag |= (val << i);
     }
     /* decode the directory/file flag */
@@ -1957,10 +1950,70 @@ static void decode_symlink(char *name, int *is_dir)
         else if (c == '.' && *p++ == '/')
             *is_dir = TRUE;
         else
-            return;
+            return NULL;
     }
     else
         *is_dir = TRUE;
+    if (tag) *tag = reparse_tag;
+    return p;
+}
+
+static int rewrite_symlink( const char *path )
+{
+    static char marker[] = "////.//.//"; /* "P" (0x50) encoded as a path (0=/ 1=./) */
+    char *link, *prefix_end, *local_link;
+    static char config_dir[MAX_PATH];
+    static int config_dir_len = 0;
+    char new_target[PATH_MAX];
+    int len, is_dir, i;
+    ULONG tag;
+
+    /* obtain the wine prefix path */
+    if (!config_dir_len)
+    {
+        char tmp_dir[MAX_PATH];
+
+        if (getcwd( tmp_dir, sizeof(tmp_dir) ) == NULL) return FALSE;
+        if (fchdir( config_dir_fd ) == -1) return FALSE;
+        if (getcwd( config_dir, sizeof(config_dir) ) == NULL) return FALSE;
+        if (chdir( tmp_dir ) == -1) return FALSE;
+        config_dir_len = strlen( config_dir );
+    }
+
+    /* grab the current link contents */
+    link = decode_symlink( path, &tag, &is_dir );
+    if (link == NULL) return FALSE;
+
+    /* find out if the prefix matches, if it does then do not modify the link */
+    prefix_end = strstr( link, marker );
+    if (prefix_end == NULL) return TRUE;
+    local_link = prefix_end + strlen( marker );
+    len = prefix_end - link;
+    if (len == config_dir_len && strncmp( config_dir, link, len ) == 0) return TRUE;
+    /* if the prefix does not match then re-encode the link with the new prefix */
+
+    /* Encode the reparse tag into the symlink */
+    strcpy( new_target, "/" );
+    for (i = 0; i < sizeof(ULONG)*8; i++)
+    {
+        if ((tag >> i) & 1)
+            strcat( new_target, "." );
+        strcat( new_target, "/" );
+    }
+    /* Encode the type (file or directory) if NT symlink */
+    if (tag == IO_REPARSE_TAG_SYMLINK)
+    {
+        if (is_dir)
+            strcat( new_target, "." );
+        strcat( new_target, "/" );
+    }
+    strcat( new_target, config_dir );
+    strcat( new_target, marker );
+    strcat( new_target, local_link );
+    /* replace the symlink */
+    unlink( path );
+    symlink( new_target, path );
+    return TRUE;
 }
 
 /* open() wrapper that returns a struct fd with no fd user set */
@@ -2026,7 +2079,7 @@ struct fd *open_fd( struct fd *root, const char *name, struct unicode_str nt_nam
     fd->unix_name = NULL;
     if ((path = dup_fd_name( root, name )))
     {
-        int is_symlink = check_symlink( path );
+        int is_symlink = rewrite_symlink( path );
 #if defined(O_SYMLINK)
         if (is_symlink && (options & FILE_OPEN_REPARSE_POINT) && !(flags & O_CREAT))
             flags |= O_SYMLINK;
@@ -2090,7 +2143,7 @@ struct fd *open_fd( struct fd *root, const char *name, struct unicode_str nt_nam
         *mode = st.st_mode;
         is_dir = S_ISDIR(st.st_mode);
         if (is_link)
-            decode_symlink(fd->unlink_name, &is_dir);
+            decode_symlink(fd->unlink_name, NULL, &is_dir);
 
         /* check directory options */
         if ((options & FILE_DIRECTORY_FILE) && !is_dir)