libfprint/examples/storage.c

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/*
* Trivial storage driver for example programs
*
* Copyright (C) 2019 Benjamin Berg <bberg@redhat.com>
* Copyright (C) 2019 Marco Trevisan <marco.trevisan@canonical.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
#include <libfprint/fprint.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define STORAGE_FILE "test-storage.variant"
static char *
get_print_data_descriptor (FpPrint *print, FpDevice *dev, FpFinger finger)
{
const char *driver;
const char *dev_id;
if (print) {
driver = fp_print_get_driver (print);
dev_id = fp_print_get_device_id (print);
} else {
driver = fp_device_get_driver (dev);
dev_id = fp_device_get_device_id (dev);
}
return g_strdup_printf("%s/%s/%x",
driver,
dev_id,
finger);
}
static GVariantDict *
load_data(void)
{
GVariantDict *res;
GVariant *var;
g_autofree gchar *contents = NULL;
gssize length = 0;
if (!g_file_get_contents (STORAGE_FILE, &contents, &length, NULL)) {
g_warning ("Error loading storage, assuming it is empty");
return g_variant_dict_new(NULL);
}
var = g_variant_new_from_data (G_VARIANT_TYPE_VARDICT, contents, length, FALSE, NULL, NULL);
res = g_variant_dict_new(var);
g_variant_unref(var);
return res;
}
static int
save_data(GVariant *data)
{
const gchar *contents = NULL;
gsize length;
length = g_variant_get_size(data);
contents = (gchar*) g_variant_get_data (data);
if (!g_file_set_contents (STORAGE_FILE, contents, length, NULL)) {
g_warning ("Error saving storage,!");
return -1;
}
g_variant_ref_sink(data);
g_variant_unref(data);
return 0;
}
int
print_data_save(FpPrint *print, FpFinger finger)
{
g_autofree gchar *descr = get_print_data_descriptor (print, NULL, finger);
g_autoptr (GError) error = NULL;
g_autoptr (GVariantDict) dict = NULL;
g_autofree guchar *data = NULL;
GVariant *val;
gsize size;
int res;
dict = load_data();
fp_print_serialize (print, &data, &size, &error);
if (error) {
g_warning ("Error serializing data: %s", error->message);
return -1;
}
val = g_variant_new_fixed_array (G_VARIANT_TYPE("y"), data, size, 1);
g_variant_dict_insert_value (dict, descr, val);
res = save_data(g_variant_dict_end(dict));
return res;
}
FpPrint *
print_data_load(FpDevice *dev, FpFinger finger)
{
g_autofree gchar *descr = get_print_data_descriptor (NULL, dev, finger);
g_autoptr (GVariant) val = NULL;
g_autoptr (GVariantDict) dict = NULL;
g_autofree guchar *stored_data = NULL;
gsize stored_len;
dict = load_data();
val = g_variant_dict_lookup_value (dict, descr, G_VARIANT_TYPE ("ay"));
if (val) {
FpPrint *print;
g_autoptr (GError) error = NULL;
stored_data = (guchar*) g_variant_get_fixed_array (val, &stored_len, 1);
print = fp_print_deserialize (stored_data, stored_len, &error);
if (error)
g_warning ("Error deserializing data: %s", error->message);
return print;
}
return NULL;
}
FpPrint *
print_create_template (FpDevice *dev, FpFinger finger)
{
g_autoptr(GDateTime) datetime = NULL;
FpPrint *template = NULL;
GDate *date = NULL;
gint year, month, day;
template = fp_print_new (dev);
fp_print_set_finger (template, finger);
fp_print_set_username (template, g_get_user_name ());
datetime = g_date_time_new_now_local ();
g_date_time_get_ymd (datetime, &year, &month, &day);
date = g_date_new_dmy (day, month, year);
fp_print_set_enroll_date (template, date);
g_date_free (date);
return template;
}
static gboolean
save_image_to_pgm (FpImage *img, const char *path)
{
FILE *fd = fopen (path, "w");
size_t write_size;
const guchar *data = fp_image_get_data (img, &write_size);
int r;
if (!fd) {
g_warning("could not open '%s' for writing: %d", path, errno);
return FALSE;
}
r = fprintf (fd, "P5 %d %d 255\n",
fp_image_get_width (img), fp_image_get_height (img));
if (r < 0) {
fclose(fd);
g_critical("pgm header write failed, error %d", r);
return FALSE;
}
r = fwrite (data, 1, write_size, fd);
if (r < write_size) {
fclose(fd);
g_critical("short write (%d)", r);
return FALSE;
}
fclose (fd);
g_debug ("written to '%s'", path);
return TRUE;
}
gboolean print_image_save (FpPrint *print, const char *path)
{
g_autoptr(FpImage) img = NULL;
g_return_val_if_fail (FP_IS_PRINT (print), FALSE);
g_return_val_if_fail (path != NULL, FALSE);
img = fp_print_get_image (print);
if (img)
return save_image_to_pgm (img, path);
return FALSE;
}