symlink: nfs41_symlink_follow() for readdir and open

added nfs41_file_info.symlink_dir to replace readdir's info.cansettime hack.  when nfs_file_info_to_attributes() finds info.type==NF4LNK, it adds the FILE_ATTRIBUTE_DIRECTORY flag if info.symlink_dir is set

renamed nfs41_symlink_follow() to nfs41_symlink_target()
generalized lookup_symlink() into nfs41_symlink_follow(), which is called by readdir and open (also avoids an extra lookup)

added queries for symlink target type when doing normal GETATTRs (getattr.c) and opens with OPEN_REPARSE_POINT set (open.c)

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>

daemon/getattr.c

@@ -93,6 +93,14 @@ int handle_getattr(nfs41_upcall *upcall)
         goto out;
     }
 
+    if (info.type == NF4LNK) {
+        nfs41_file_info target_info;
+        int target_status = nfs41_symlink_follow(args->root,
+            state->session, &state->file, &target_info);
+        if (target_status == NO_ERROR && target_info.type == NF4DIR)
+            info.symlink_dir = TRUE;
+    }
+
     switch (args->query_class) {
     case FileBasicInformation:
         nfs_to_basic_info(&info, &args->basic_info);

daemon/nfs41_ops.h

@@ -1022,11 +1022,17 @@ int nfs41_link(
     OUT OPTIONAL nfs41_path_fh *link_out);
 
 /* symlink.c */
-int nfs41_symlink_follow(
+int nfs41_symlink_target(
     IN nfs41_session *session,
     IN nfs41_path_fh *file,
     OUT nfs41_abs_path *target);
 
+int nfs41_symlink_follow(
+    IN nfs41_root *root,
+    IN nfs41_session *session,
+    IN nfs41_path_fh *symlink,
+    OUT nfs41_file_info *info);
+
 int nfs41_readlink(
     IN nfs41_session *session,
     IN nfs41_path_fh *file,

daemon/nfs41_types.h

@@ -184,6 +184,7 @@ typedef struct __nfs41_file_info {
     bool_t                  cansettime; /* XXX: per-fs */
     bool_t                  case_insensitive;
     bool_t                  case_preserving;
+    bool_t                  symlink_dir;
 } nfs41_file_info;
 
 #endif /* !__NFS41_DAEMON_TYPES_H__ */

daemon/open.c

@@ -217,7 +217,7 @@ int handle_open(nfs41_upcall *upcall)
     int status = 0;
     open_upcall_args *args = &upcall->args.open;
     nfs41_open_state *state;
-    nfs41_file_info info;
+    nfs41_file_info info = { 0 };
 
     status = create_open_state(args->path, args->open_owner_id, &state);
     if (status) {
@@ -242,7 +242,7 @@ int handle_open(nfs41_upcall *upcall)
         args->symlink_embedded = TRUE;
 
         /* replace the path with the symlink target */
-        status = nfs41_symlink_follow(state->session,
+        status = nfs41_symlink_target(state->session,
             &state->parent, &args->symlink);
         goto out_free_state;
     }
@@ -270,14 +270,20 @@ int handle_open(nfs41_upcall *upcall)
         } else if (info.type == NF4LNK) {
             dprintf(2, "handle nfs41_open: SYMLINK\n");
             if (args->create_opts & FILE_OPEN_REPARSE_POINT) {
-                /* continue and open the symlink itself */
+                /* continue and open the symlink itself, but we need to
+                 * know if the target is a regular file or directory */
+                nfs41_file_info target_info;
+                int target_status = nfs41_symlink_follow(args->root,
+                    state->session, &state->file, &target_info);
+                if (target_status == NO_ERROR && target_info.type == NF4DIR)
+                    info.symlink_dir = TRUE;
             } else {
                 /* tell the driver to call RxPrepareToReparseSymbolicLink() */
                 upcall->last_error = ERROR_REPARSE;
                 args->symlink_embedded = FALSE;
 
                 /* replace the path with the symlink target */
-                status = nfs41_symlink_follow(state->session,
+                status = nfs41_symlink_target(state->session,
                     &state->file, &args->symlink);
                 goto out_free_state;
             }

daemon/readdir.c

@@ -170,10 +170,6 @@ static void readdir_copy_dir_info(
             entry->attr_info.size;
     info->fdi.FileAttributes = nfs_file_info_to_attributes(
         &entry->attr_info);
-
-    /* use cansettime to flag the symlink target as a directory */
-    if (entry->attr_info.cansettime)
-        info->fdi.FileAttributes |= FILE_ATTRIBUTE_DIRECTORY;
 }
 
 static void readdir_copy_shortname(
@@ -249,7 +245,7 @@ static int lookup_entry(
     int status;
 
     name.name = entry->name;
-    name.len = (unsigned short)entry->name_len;
+    name.len = (unsigned short)entry->name_len - 1;
 
     status = format_abs_path(parent->path, &name, &path);
     if (status) goto out;
@@ -269,7 +265,7 @@ static int lookup_symlink(
     OUT nfs41_file_info *info_out)
 {
     nfs41_abs_path path;
-    nfs41_path_fh link_parent, file;
+    nfs41_path_fh file;
     nfs41_file_info info;
     int status;
 
@@ -277,28 +273,15 @@ static int lookup_symlink(
     if (status) goto out;
 
     file.path = &path;
-    /* get a filehandle for the symlink */
+    status = nfs41_lookup(root, session, &path, NULL, &file, &info, &session);
-    status = nfs41_lookup(root, session, &path, NULL, &file, &info, NULL);
     if (status) goto out;
 
-    link_parent.path = &path;
     last_component(path.path, path.path + path.len, &file.name);
-    last_component(path.path, file.name.name, &link_parent.name);
 
-    /* attempt to follow the symlink */
+    status = nfs41_symlink_follow(root, session, &file, &info);
-    status = nfs41_symlink_follow(session, &file, &path);
     if (status) goto out;
 
-    /* get attributes for the target */
+    info_out->symlink_dir = info.type == NF4DIR;
-    status = nfs41_lookup(root, session, &path, &link_parent, NULL, &info, NULL);
-    if (status) goto out;
-
-    if (info.type == NF4LNK) {
-        status = lookup_symlink(root, session, &link_parent, &file.name, &info);
-        if (status) goto out;
-        info_out->cansettime = info.cansettime;
-    } else if (info.type == NF4DIR)
-        info_out->cansettime = 1;
 out:
     return status;
 }

daemon/symlink.c

@@ -42,8 +42,6 @@ static int abs_path_link(
     const char *link_end = link + link_len;
     int status = NO_ERROR;
 
-    dprintf(2, "--> abs_path_link('%s', '%s')\n", path->path, link);
-
     /* if link is an absolute path, start path_pos at the beginning */
     if (is_delimiter(*link))
         path_pos = path->path;
@@ -91,11 +89,10 @@ static int abs_path_link(
     *path_pos = '\0';
 out:
     path->len = (unsigned short)(path_pos - path->path);
-    dprintf(2, "<-- abs_path_link('%s') returning %d\n", path->path, status);
     return status;
 }
 
-int nfs41_symlink_follow(
+int nfs41_symlink_target(
     IN nfs41_session *session,
     IN nfs41_path_fh *file,
     OUT nfs41_abs_path *target)
@@ -114,6 +111,8 @@ int nfs41_symlink_follow(
         goto out;
     }
 
+    dprintf(2, "--> nfs41_symlink_target('%s', '%s')\n", path->path, link);
+
     /* overwrite the last component of the path; get the starting offset */
     path_offset = file->name.name - path->path;
 
@@ -127,7 +126,6 @@ int nfs41_symlink_follow(
     status = abs_path_link(target, target->path + path_offset, link, link_len);
     if (status) {
         eprintf("abs_path_link() failed with %d\n", status);
-        status = ERROR_PATH_NOT_FOUND;
         goto out;
     }
 
@@ -139,6 +137,44 @@ int nfs41_symlink_follow(
     }
     target->len = (unsigned short)strlen(target->path);
 out:
+    dprintf(2, "<-- nfs41_symlink_target('%s') returning %d\n",
+        target->path, status);
+    return status;
+}
+
+int nfs41_symlink_follow(
+    IN nfs41_root *root,
+    IN nfs41_session *session,
+    IN nfs41_path_fh *symlink,
+    OUT nfs41_file_info *info)
+{
+    nfs41_abs_path path;
+    nfs41_path_fh file;
+    int status = NO_ERROR;
+
+    file.path = &path;
+    InitializeSRWLock(&path.lock);
+
+    dprintf(2, "--> nfs41_symlink_follow('%s')\n", symlink->path->path);
+
+    do {
+        /* construct the target path */
+        status = nfs41_symlink_target(session, symlink, &path);
+        if (status) goto out;
+
+        dprintf(2, "looking up '%s'\n", path.path);
+
+        last_component(path.path, path.path + path.len, &file.name);
+
+        /* get attributes for the target */
+        status = nfs41_lookup(root, session, &path,
+            NULL, &file, info, &session);
+        if (status) goto out;
+
+        symlink = &file;
+    } while (info->type == NF4LNK);
+out:
+    dprintf(2, "<-- nfs41_symlink_follow() returning %d\n", status);
     return status;
 }
 

daemon/util.c

@@ -130,9 +130,11 @@ ULONG nfs_file_info_to_attributes(
     ULONG attrs = 0;
     if (info->type == NF4DIR)
         attrs |= FILE_ATTRIBUTE_DIRECTORY;
-    else if (info->type == NF4LNK)
+    else if (info->type == NF4LNK) {
         attrs |= FILE_ATTRIBUTE_REPARSE_POINT;
-    else if (info->type != NF4REG)
+        if (info->symlink_dir)
+            attrs |= FILE_ATTRIBUTE_DIRECTORY;
+    } else if (info->type != NF4REG)
         dprintf(1, "unhandled file type %d, defaulting to NF4REG\n",
             info->type);
 
@@ -162,11 +164,13 @@ void nfs_to_standard_info(
     IN const nfs41_file_info *info,
     OUT PFILE_STANDARD_INFO std_out)
 {
+    const ULONG FileAttributes = nfs_file_info_to_attributes(info);
+
     std_out->AllocationSize.QuadPart =
         std_out->EndOfFile.QuadPart = (LONGLONG)info->size;
     std_out->NumberOfLinks = info->numlinks;
     std_out->DeletePending = FALSE;
-    std_out->Directory = info->type == NF4DIR ? TRUE : FALSE;
+    std_out->Directory = FileAttributes & FILE_ATTRIBUTE_DIRECTORY;
 }