xfce-gio-extensions

Related : thunar#156 (comment 18095)

xfce_g_file_metadata_is_supported : Check if metadata is supported
xfce_g_file_create_checksum       : Generate SHA-256 of the file
xfce_g_file_set_trusted           : Set trusted attribute/checksum in metadata
xfce_g_file_is_trusted            : Check trusted attribute/checksum

MR !16

7 files changed, 392 insertions, 0 deletions

diff --git a/docs/reference/libxfce4util-docs.xml b/docs/reference/libxfce4util-docs.xml
index ea5888d..5b7f742 100644
--- a/docs/reference/libxfce4util-docs.xml
+++ b/docs/reference/libxfce4util-docs.xml
@@ -49,6 +49,7 @@
         <xi:include href="xml/xfce-fileutils.xml"/>
         <xi:include href="xml/xfce-miscutils.xml"/>
         <xi:include href="xml/xfce-utf8.xml"/>
+        <xi:include href="xml/xfce-gio-extensions.xml"/>
     </chapter>
 
     <chapter id="libxfce4util-datatypes">
diff --git a/docs/reference/libxfce4util-sections.txt b/docs/reference/libxfce4util-sections.txt
index 4563cd9..3832504 100644
--- a/docs/reference/libxfce4util-sections.txt
+++ b/docs/reference/libxfce4util-sections.txt
@@ -112,6 +112,15 @@ xfce_utf8_strndup
 xfce_mkdirhier
 </SECTION>
 
+<SECTION>
+<TITLE>GIO Extensions</TITLE>
+<FILE>xfce-gio-extensions</FILE>
+xfce_g_file_metadata_is_supported
+xfce_g_file_create_checksum
+xfce_g_file_set_trusted
+xfce_g_file_is_trusted
+</SECTION>
+
 
 <SECTION>
 <TITLE>Software Licenses</TITLE>
diff --git a/libxfce4util/Makefile.am b/libxfce4util/Makefile.am
index 996706e..a309a62 100644
--- a/libxfce4util/Makefile.am
+++ b/libxfce4util/Makefile.am
@@ -24,6 +24,7 @@ libxfce4util_headers =							\
 	xfce-debug.h							\
 	xfce-fileutils.h						\
 	xfce-generics.h							\
+	xfce-gio-extensions.h						\
 	xfce-i18n.h							\
 	xfce-kiosk.h							\
 	xfce-license.h							\
@@ -50,6 +51,7 @@ libxfce4util_la_SOURCES =						\
 	libxfce4util-private.c						\
 	libxfce4util-private.h						\
 	xfce-fileutils.c						\
+	xfce-gio-extensions.c						\
 	xfce-i18n.c							\
 	xfce-kiosk.c							\
 	xfce-license.c							\
diff --git a/libxfce4util/libxfce4util.h b/libxfce4util/libxfce4util.h
index 5cbd0ee..ea110cc 100644
--- a/libxfce4util/libxfce4util.h
+++ b/libxfce4util/libxfce4util.h
@@ -37,6 +37,7 @@
 #include <libxfce4util/xfce-rc.h>
 #include <libxfce4util/xfce-resource.h>
 #include <libxfce4util/xfce-utf8.h>
+#include <libxfce4util/xfce-gio-extensions.h>
 
 #undef LIBXFCE4UTIL_INSIDE_LIBXFCE4UTIL_H
 
diff --git a/libxfce4util/libxfce4util.symbols b/libxfce4util/libxfce4util.symbols
index db4ae00..17da2c1 100644
--- a/libxfce4util/libxfce4util.symbols
+++ b/libxfce4util/libxfce4util.symbols
@@ -52,6 +52,16 @@ xfce_mkdirhier
 #endif
 #endif
 
+/* xfce-gio-extensions functions */
+#if IN_HEADER(__XFCE_GIO_EXTENSIONS_H__)
+#if IN_SOURCE(__XFCE_GIO_EXTENSIONS_C__)
+xfce_g_file_metadata_is_supported
+xfce_g_file_create_checksum
+xfce_g_file_set_trusted
+xfce_g_file_is_trusted
+#endif
+#endif
+
 /* xfce-i18n functions */
 #if IN_HEADER(__XFCE_I18N_H__)
 #if IN_SOURCE(__XFCE_I18N_C__)
diff --git a/libxfce4util/xfce-gio-extensions.c b/libxfce4util/xfce-gio-extensions.c
new file mode 100644
index 0000000..2f994bf
--- /dev/null
+++ b/libxfce4util/xfce-gio-extensions.c
@@ -0,0 +1,327 @@
+/*
+ * Copyright (c) 2021 Yongha Hwang <mshrimp@sogang.ac.kr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+/**
+ * SECTION:xfce-gio-extensions
+ * @title: GIO Extensions
+ * @short_description: various extensions to GIO
+ * @include: libxfce4util/libxfce4util.h
+ *
+ * Common used functions for I/O that are not provided by the Glib library
+ *
+ * Since: 4.17
+ **/
+
+
+
+#include <libxfce4util/libxfce4util.h>
+#include <libxfce4util/libxfce4util-alias.h>
+
+
+
+#define XFCE_ATTRIBUTE_EXECUTABLE_CHECKSUM "metadata::xfce-exe-checksum" /* string */
+
+
+
+/**
+ * xfce_g_file_metadata_is_supported:
+ * @file: a #GFile.
+ *
+ * Checks if GVFS-metadata is available for
+ * the @file provided.
+ *
+ * Returns: %TRUE is GVFS-metadata is supported, %FALSE otherwise.
+ *
+ * Since: 4.17
+ **/
+gboolean
+xfce_g_file_metadata_is_supported (GFile *file)
+{
+  GFileAttributeInfoList *info_list;
+  gboolean                is_supported;
+
+  g_return_val_if_fail (G_IS_FILE (file), FALSE);
+
+  info_list = g_file_query_writable_namespaces (file, NULL, NULL);
+  if (info_list == NULL)
+    return FALSE;
+
+  is_supported = (g_file_attribute_info_list_lookup (info_list, "metadata") != NULL);
+  g_file_attribute_info_list_unref (info_list);
+
+  return is_supported;
+}
+
+
+
+/**
+ * xfce_g_file_create_checksum:
+ * @file: a #GFile.
+ * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
+ * @error: (nullable): a #GError
+ *
+ * Generates an SHA-256 hash of the @file.
+ * Utilizes g_compute_checksum_for_data() which
+ * is present since Glib 2.16.
+ *
+ * Returns: (transfer full) (nullable): Checksum of the @file.
+ * If file read fails, returns %NULL. Free with g_free().
+ *
+ * Since: 4.17
+ **/
+gchar *
+xfce_g_file_create_checksum (GFile        *file,
+                             GCancellable *cancellable,
+                             GError      **error)
+{
+  GError           *error_local = NULL;
+  GFileInfo        *file_info;
+  GFileInputStream *stream;
+  guchar           *contents_buffer;
+  gchar            *checksum;
+  gsize             file_size, file_size_read;
+
+  g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+  g_return_val_if_fail (G_IS_FILE (file),                NULL);
+
+  /* query size */
+  file_info = g_file_query_info (file,
+                                 G_FILE_ATTRIBUTE_STANDARD_SIZE,
+                                 G_FILE_QUERY_INFO_NONE,
+                                 cancellable,
+                                 &error_local);
+  if (error_local != NULL)
+    {
+      g_propagate_error (error, error_local);
+      return NULL;
+    }
+
+  file_size = g_file_info_get_size (file_info);
+  g_object_unref (file_info);
+
+  /* special case : SHA-256 hash of NULL */
+  /* e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 */
+  if (file_size == 0)
+    return g_compute_checksum_for_data (G_CHECKSUM_SHA256, NULL, 0);
+
+  /* allocate buffer */
+  contents_buffer = g_malloc (file_size);
+  if (contents_buffer == NULL)
+    {
+      if (error != NULL)
+        *error = g_error_new (G_FILE_ERROR,
+                              G_FILE_ERROR_NOMEM,
+                              "Failed to allocate memory to read file '%s'",
+                              g_file_peek_path (file));
+      return NULL;
+    }
+
+  /* read the actual file */
+  stream = g_file_read (file, cancellable, &error_local);
+  if (error_local != NULL)
+    {
+      g_free (contents_buffer);
+      g_propagate_error (error, error_local);
+      return NULL;
+    }
+
+  g_input_stream_read_all (G_INPUT_STREAM (stream),
+                           contents_buffer,
+                           file_size,
+                           &file_size_read,
+                           cancellable,
+                           &error_local);
+  g_object_unref (stream);
+
+  if (error_local != NULL)
+    {
+      g_free (contents_buffer);
+      g_propagate_error (error, error_local);
+      return NULL;
+    }
+
+  checksum = g_compute_checksum_for_data (G_CHECKSUM_SHA256,
+                                          contents_buffer,
+                                          file_size_read);
+
+  g_free (contents_buffer);
+
+  return checksum;
+}
+
+
+
+/**
+ * xfce_g_file_set_trusted:
+ * @file: a #GFile.
+ * @is_trusted: #TRUE if trusted, #FALSE if not
+ * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
+ * @error: (nullable): a #GError
+ *
+ * Sets the "safety flag" on if @is_trusted.
+ *
+ * Safety flag is a new concept introduced in
+ * XFCE 4.17. It is basically an additional
+ * execution flag stored in GVFS-metadata.
+ * Unlike the execution flag (+x), it is safe
+ * to assume that this flag did not come from
+ * foreign location (for example, by downloading
+ * an tar archive) and is set by user.
+ *
+ * The checksum of the file is stored, and
+ * would be considered "on" only if checksum
+ * matches with the file on execution.
+ *
+ * Returns: %TRUE on success, %FALSE on error.
+ *
+ * Since: 4.17
+ **/
+gboolean
+xfce_g_file_set_trusted (GFile        *file,
+                         gboolean      is_trusted,
+                         GCancellable *cancellable,
+                         GError      **error)
+{
+  GError  *error_local = NULL;
+  gchar   *checksum_string;
+
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+  g_return_val_if_fail (G_IS_FILE (file),                FALSE);
+
+  if (!xfce_g_file_metadata_is_supported (file))
+    {
+      if (error != NULL)
+        *error = g_error_new (G_FILE_ERROR,
+                              G_FILE_ERROR_NOSYS,
+                              "GVFS-metadata is not supported for file '%s'",
+                              g_file_peek_path (file));
+      return FALSE;
+    }
+
+  if (is_trusted)
+    {
+      checksum_string = xfce_g_file_create_checksum (file, cancellable, &error_local);
+      if (error_local != NULL)
+        {
+          g_propagate_error (error, error_local);
+          return FALSE;
+        }
+    }
+  else
+    checksum_string = NULL;
+
+  g_file_set_attribute (file,
+                        XFCE_ATTRIBUTE_EXECUTABLE_CHECKSUM,
+                        is_trusted ? G_FILE_ATTRIBUTE_TYPE_STRING : G_FILE_ATTRIBUTE_TYPE_INVALID,
+                        checksum_string,
+                        G_FILE_ATTRIBUTE_INFO_COPY_WITH_FILE | G_FILE_ATTRIBUTE_INFO_COPY_WHEN_MOVED,
+                        cancellable,
+                        &error_local);
+  g_free (checksum_string);
+
+  if (error_local != NULL)
+    {
+      g_propagate_error (error, error_local);
+      return FALSE;
+    }
+  return TRUE;
+}
+
+
+
+/**
+ * xfce_g_file_is_trusted:
+ * @file: a #GFile.
+ * @cancellable: (nullable): optional #GCancellable object, %NULL to ignore.
+ * @error: (nullable): a #GError
+ *
+ * Compares the checksum stored in safety flag
+ * with the actual file. If it matches, it
+ * is considered safe.
+ *
+ * Read the documentation of
+ * xfce_g_file_set_trusted() for details.
+ *
+ * Returns: %TRUE if safety flag is verified
+ * or not supported. %FALSE otherwise.
+ *
+ * Since: 4.17
+ **/
+gboolean
+xfce_g_file_is_trusted (GFile        *file,
+                        GCancellable *cancellable,
+                        GError      **error)
+{
+  GError      *error_local = NULL;
+  GFileInfo   *file_info;
+  gboolean     is_trusted;
+  const gchar *attribute_string;
+  gchar       *checksum_string;
+
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+  g_return_val_if_fail (G_IS_FILE (file), FALSE);
+
+  if (!xfce_g_file_metadata_is_supported (file))
+    {
+      if (error != NULL)
+        *error = g_error_new (G_FILE_ERROR,
+                              G_FILE_ERROR_NOSYS,
+                              "GVFS-metadata is not supported for file '%s'",
+                              g_file_peek_path (file));
+      return TRUE;
+    }
+
+  file_info = g_file_query_info (file,
+                                 XFCE_ATTRIBUTE_EXECUTABLE_CHECKSUM,
+                                 G_FILE_QUERY_INFO_NONE,
+                                 cancellable,
+                                 &error_local);
+  if (error_local != NULL)
+    {
+      g_propagate_error (error, error_local);
+      return FALSE;
+    }
+
+  attribute_string = g_file_info_get_attribute_string (file_info,
+                                                       XFCE_ATTRIBUTE_EXECUTABLE_CHECKSUM);
+  if (attribute_string != NULL)
+    {
+      checksum_string = xfce_g_file_create_checksum (file, cancellable, &error_local);
+      if (error_local != NULL)
+        {
+          g_object_unref (file_info);
+          g_propagate_error (error, error_local);
+          return FALSE;
+        }
+      is_trusted = (g_strcmp0 (attribute_string, checksum_string) == 0);
+      g_info ("== Safety flag check ==");
+      g_info ("Attribute checksum: %s", attribute_string);
+      g_info ("File checksum     : %s", checksum_string);
+      g_free (checksum_string);
+    }
+  else
+    is_trusted = FALSE;
+
+  g_object_unref (file_info);
+
+  return is_trusted;
+}
+
+#define __XFCE_GIO_EXTENSIONS_C__
+#include <libxfce4util/libxfce4util-aliasdef.c>
diff --git a/libxfce4util/xfce-gio-extensions.h b/libxfce4util/xfce-gio-extensions.h
new file mode 100644
index 0000000..aa58e06
--- /dev/null
+++ b/libxfce4util/xfce-gio-extensions.h
@@ -0,0 +1,42 @@
+/*-
+ * Copyright (c) 2021 Yongha Hwang <mshrimp@sogang.ac.kr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#if !defined(LIBXFCE4UTIL_INSIDE_LIBXFCE4UTIL_H) && !defined(LIBXFCE4UTIL_COMPILATION)
+#error "Only <libxfce4util/libxfce4util.h> can be included directly, this file may disappear or change contents"
+#endif
+
+#ifndef __XFCE_GIO_EXTENSIONS_H__
+#define __XFCE_GIO_EXTENSIONS_H__
+
+#include <glib.h>
+#include <gio/gio.h>
+
+gboolean      xfce_g_file_metadata_is_supported   (GFile        *file);
+gchar        *xfce_g_file_create_checksum         (GFile        *file,
+                                                   GCancellable *cancellable,
+                                                   GError      **error);
+gboolean      xfce_g_file_set_trusted             (GFile        *file,
+                                                   gboolean      is_trusted,
+                                                   GCancellable *cancellable,
+                                                   GError      **error);
+gboolean      xfce_g_file_is_trusted              (GFile        *file,
+                                                   GCancellable *cancellable,
+                                                   GError      **error);
+
+#endif /*__XFCE_GIO_EXTENSIONS_H__*/