lib: Use GLib and libusb directly for debug output

Use GLib internally to output debug information, and tell about
libusb's LIBUSB_DEBUG envvar for libusb debug.

fp_set_debug() is now a no-op.

https://bugs.freedesktop.org/show_bug.cgi?id=106552

libfprint/aeslib.c

@@ -19,13 +19,14 @@
 
 #define FP_COMPONENT "aeslib"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
 #include <libusb.h>
 #include <glib.h>
 
-#include "fp_internal.h"
 #include "assembling.h"
 #include "aeslib.h"
 

libfprint/assembling.c

@@ -21,13 +21,14 @@
 
 #define FP_COMPONENT "assembling"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
 #include <libusb.h>
 #include <glib.h>
 
-#include "fp_internal.h"
 #include "assembling.h"
 
 static unsigned int calc_error(struct fpi_frame_asmbl_ctx *ctx,

libfprint/async.c

@@ -19,12 +19,12 @@
 
 #define FP_COMPONENT "async"
 
+#include "fp_internal.h"
+
 #include <config.h>
 #include <errno.h>
 #include <glib.h>
 
-#include "fp_internal.h"
-
 /* Drivers call this when device initialisation has completed */
 void fpi_drvcb_open_complete(struct fp_dev *dev, int status)
 {

libfprint/core.c

@@ -27,9 +27,6 @@
 
 #include "fp_internal.h"
 
-static int log_level = 0;
-static int log_level_fixed = 0;
-
 libusb_context *fpi_usb_ctx = NULL;
 GSList *opened_devices = NULL;
 
@@ -116,52 +113,6 @@ GSList *opened_devices = NULL;
 
 static GSList *registered_drivers = NULL;
 
-void fpi_log(enum fpi_log_level level, const char *component,
-	const char *function, const char *format, ...)
-{
-	va_list args;
-	FILE *stream = stdout;
-	const char *prefix;
-
-	if (!log_level)
-		return;
-	if (level == FPRINT_LOG_LEVEL_WARNING && log_level < 2)
-		return;
-	if (level == FPRINT_LOG_LEVEL_INFO && log_level < 3)
-		return;
-
-	switch (level) {
-	case FPRINT_LOG_LEVEL_INFO:
-		prefix = "info";
-		break;
-	case FPRINT_LOG_LEVEL_WARNING:
-		stream = stderr;
-		prefix = "warning";
-		break;
-	case FPRINT_LOG_LEVEL_ERROR:
-		stream = stderr;
-		prefix = "error";
-		break;
-	case FPRINT_LOG_LEVEL_DEBUG:
-		stream = stderr;
-		prefix = "debug";
-		break;
-	default:
-		stream = stderr;
-		prefix = "unknown";
-		break;
-	}
-
-	fprintf(stream, "%s:%s [%s] ", component ? component : "fp", prefix,
-		function);
-
-	va_start (args, format);
-	vfprintf(stream, format, args);
-	va_end (args);
-
-	fprintf(stream, "\n");
-}
-
 static void register_driver(struct fp_driver *drv)
 {
 	if (drv->id == 0) {
@@ -787,38 +738,11 @@ API_EXPORTED int fp_dev_get_img_height(struct fp_dev *dev)
  * fp_set_debug:
  * @level: the verbosity level
  *
- * Set message verbosity.
- *  - Level 0: no messages ever printed by the library (default)
- *  - Level 1: error messages are printed to stderr
- *  - Level 2: warning and error messages are printed to stderr
- *  - Level 3: informational messages are printed to stdout, warning and error
- *    messages are printed to stderr
- *
- * The default level is 0, which means no messages are ever printed. If you
- * choose to increase the message verbosity level, ensure that your
- * application does not close the stdout/stderr file descriptors.
- *
- * You are advised to set level 3. libfprint is conservative with its message
- * logging and most of the time, will only log messages that explain error
- * conditions and other oddities. This will help you debug your software.
- *
- * If the LIBFPRINT_DEBUG environment variable was set when libfprint was
- * initialized, this function does nothing: the message verbosity is fixed
- * to the value in the environment variable.
- *
- * If libfprint was compiled without any message logging, this function does
- * nothing: you'll never get any messages.
- *
- * If libfprint was compiled with verbose debug message logging, this function
- * does nothing: you'll always get messages from all levels.
+ * This call does nothing, see fp_init() for details.
  */
 API_EXPORTED void fp_set_debug(int level)
 {
-	if (log_level_fixed)
-		return;
-
-	log_level = level;
-	libusb_set_debug(fpi_usb_ctx, level);
+	/* Nothing */
 }
 
 /**
@@ -827,11 +751,27 @@ API_EXPORTED void fp_set_debug(int level)
  * Initialise libfprint. This function must be called before you attempt to
  * use the library in any way.
  *
+ * To enable debug output of libfprint specifically, use GLib's `G_MESSAGES_DEBUG`
+ * environment variable as explained in [Running and debugging GLib Applications](https://developer.gnome.org/glib/stable/glib-running.html#G_MESSAGES_DEBUG).
+ *
+ * The log domains used in libfprint are either `libfprint` or `libfprint-FP_COMPONENT`
+ * where `FP_COMPONENT` is defined in the source code for each driver, or component
+ * of the library. Starting with `all` and trimming down is advised.
+ *
+ * To enable debugging of libusb, for USB-based fingerprint reader drivers, use
+ * libusb's `LIBUSB_DEBUG` environment variable as explained in the
+ * [libusb-1.0 API Reference](http://libusb.sourceforge.net/api-1.0/#msglog).
+ *
+ * Example:
+ *
+ * ```
+ * LIBUSB_DEBUG=4 G_MESSAGES_DEBUG=all my-libfprint-application
+ * ```
+ *
  * Returns: 0 on success, non-zero on error.
  */
 API_EXPORTED int fp_init(void)
 {
-	char *dbg = getenv("LIBFPRINT_DEBUG");
 	int r;
 	G_DEBUG_HERE();
 
@@ -839,14 +779,6 @@ API_EXPORTED int fp_init(void)
 	if (r < 0)
 		return r;
 
-	if (dbg) {
-		log_level = atoi(dbg);
-		if (log_level) {
-			log_level_fixed = 1;
-			libusb_set_debug(fpi_usb_ctx, log_level);
-		}
-	}
-
 	register_drivers();
 	fpi_poll_init();
 	return 0;

libfprint/drivers/aes1610.c

@@ -25,6 +25,8 @@
 
 #define FP_COMPONENT "aes1610"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
@@ -32,7 +34,6 @@
 
 #include <assembling.h>
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "driver_ids.h"
 

libfprint/drivers/aes1660.c

@@ -19,6 +19,8 @@
 
 #define FP_COMPONENT "aes1660"
 
+#include "fp_internal.h"
+
 #include <stdio.h>
 
 #include <errno.h>
@@ -26,7 +28,6 @@
 
 #include <libusb.h>
 
-#include <fp_internal.h>
 
 #include <assembling.h>
 #include <aeslib.h>

libfprint/drivers/aes2501.c

@@ -23,6 +23,8 @@
 
 #define FP_COMPONENT "aes2501"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
@@ -30,7 +32,6 @@
 
 #include <assembling.h>
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aes2501.h"
 #include "driver_ids.h"

libfprint/drivers/aes2550.c

@@ -23,6 +23,8 @@
 
 #define FP_COMPONENT "aes2550"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
@@ -30,7 +32,6 @@
 
 #include <assembling.h>
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aes2550.h"
 #include "driver_ids.h"

libfprint/drivers/aes2660.c

@@ -19,6 +19,8 @@
 
 #define FP_COMPONENT "aes2660"
 
+#include "fp_internal.h"
+
 #include <stdio.h>
 
 #include <errno.h>
@@ -26,8 +28,6 @@
 
 #include <libusb.h>
 
-#include <fp_internal.h>
-
 #include <assembling.h>
 #include <aeslib.h>
 

libfprint/drivers/aes3500.c

@@ -29,13 +29,14 @@
 
 #define FP_COMPONENT "aes3500"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 
 #include <glib.h>
 #include <libusb.h>
 
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aes3k.h"
 #include "driver_ids.h"

libfprint/drivers/aes3k.c

@@ -36,13 +36,14 @@
 
 #define FP_COMPONENT "aes3k"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 
 #include <glib.h>
 #include <libusb.h>
 
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aes3k.h"
 

libfprint/drivers/aes4000.c

@@ -26,13 +26,14 @@
 
 #define FP_COMPONENT "aes4000"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 
 #include <glib.h>
 #include <libusb.h>
 
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aes3k.h"
 #include "driver_ids.h"

libfprint/drivers/aesx660.c

@@ -23,6 +23,8 @@
 
 #define FP_COMPONENT "aesX660"
 
+#include "fp_internal.h"
+
 #include <stdio.h>
 
 #include <errno.h>
@@ -32,7 +34,6 @@
 
 #include <assembling.h>
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "aesx660.h"
 

libfprint/drivers/elan.c

@@ -20,10 +20,11 @@
 
 #define FP_COMPONENT "elan"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <libusb.h>
 #include <assembling.h>
-#include <fp_internal.h>
 #include <fprint.h>
 
 #include "elan.h"

libfprint/drivers/etes603.c

@@ -33,6 +33,10 @@
  *
  */
 
+#define FP_COMPONENT "etes603"
+
+#include "fp_internal.h"
+
 #include <string.h>
 #include <stdint.h>
 #include <stdarg.h>
@@ -41,8 +45,6 @@
 #include <libusb.h>
 #include <glib.h>
 
-#define FP_COMPONENT "etes603"
-#include <fp_internal.h>
 #include "driver_ids.h"
 
 /* libusb defines */

libfprint/drivers/fdu2000.c

@@ -17,15 +17,16 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#define FP_COMPONENT "fdu2000"
+
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
 
 #include <libusb.h>
 
-#define FP_COMPONENT "fdu2000"
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 #ifndef HAVE_MEMMEM

libfprint/drivers/upeksonly.c

@@ -25,14 +25,14 @@
 
 #define FP_COMPONENT "upeksonly"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
 #include <glib.h>
 #include <libusb.h>
 
-#include <fp_internal.h>
-
 #include <assembling.h>
 
 #include "upeksonly.h"

libfprint/drivers/upektc.c

@@ -20,10 +20,11 @@
 
 #define FP_COMPONENT "upektc"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 #include <libusb.h>
-#include <fp_internal.h>
 
 #include "upektc.h"
 #include "driver_ids.h"

libfprint/drivers/upektc_img.c

@@ -19,13 +19,14 @@
 
 #define FP_COMPONENT "upektc_img"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
 #include <libusb.h>
 
 #include <aeslib.h>
-#include <fp_internal.h>
 
 #include "upektc_img.h"
 #include "driver_ids.h"

libfprint/drivers/upekts.c

@@ -27,14 +27,14 @@
 
 #define FP_COMPONENT "upekts"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 
 #include <glib.h>
 #include <libusb.h>
 
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 #define EP_IN (1 | LIBUSB_ENDPOINT_IN)

libfprint/drivers/uru4000.c

@@ -20,6 +20,8 @@
 
 #define FP_COMPONENT "uru4000"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
@@ -28,8 +30,6 @@
 #include <pk11pub.h>
 #include <libusb.h>
 
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 #define EP_INTR			(1 | LIBUSB_ENDPOINT_IN)

libfprint/drivers/vcom5s.c

@@ -19,6 +19,8 @@
 
 #define FP_COMPONENT "vcom5s"
 
+#include "fp_internal.h"
+
 /* TODO:
  * calibration?
  * image size: windows gets 300x300 through vpas enrollment util?
@@ -32,8 +34,6 @@
 #include <glib.h>
 #include <libusb.h>
 
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 #define CTRL_IN 0xc0

libfprint/drivers/vfs0050.c

@@ -19,9 +19,10 @@
 
 #define FP_COMPONENT "vfs0050"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <string.h>
-#include <fp_internal.h>
 #include <assembling.h>
 #include "driver_ids.h"
 

libfprint/drivers/vfs101.c

@@ -17,14 +17,14 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#define FP_COMPONENT "vfs101"
+
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 
-#define FP_COMPONENT "vfs101"
-
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 /* Input-Output usb endpoint */

libfprint/drivers/vfs301.c

@@ -21,6 +21,8 @@
 
 #define FP_COMPONENT "vfs301"
 
+#include "fp_internal.h"
+
 #include <errno.h>
 #include <signal.h>
 #include <string.h>
@@ -32,8 +34,6 @@
 #include "vfs301_proto.h"
 #include <unistd.h>
 
-#include <fp_internal.h>
-
 #include "driver_ids.h"
 
 /************************** GENERIC STUFF *************************************/

libfprint/drv.c

@@ -19,11 +19,11 @@
 
 #define FP_COMPONENT "drv"
 
+#include "fp_internal.h"
+
 #include <config.h>
 #include <errno.h>
 
-#include "fp_internal.h"
-
 /* SSM: sequential state machine
  * Asynchronous driver design encourages some kind of state machine behind it.
  * In most cases, the state machine is entirely linear - you only go to the

libfprint/fp_internal.h

@@ -21,8 +21,13 @@
 #define __FPRINT_INTERNAL_H__
 
 #include <config.h>
-#include <stdint.h>
 
+#ifdef FP_COMPONENT
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "libfprint-"FP_COMPONENT
+#endif
+
+#include <stdint.h>
 #include <glib.h>
 #include <libusb.h>
 
@@ -34,26 +39,10 @@
         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
         (type *)( (char *)__mptr - offsetof(type,member) );})
 
-enum fpi_log_level {
-	FPRINT_LOG_LEVEL_DEBUG,
-	FPRINT_LOG_LEVEL_INFO,
-	FPRINT_LOG_LEVEL_WARNING,
-	FPRINT_LOG_LEVEL_ERROR,
-};
-
-void fpi_log(enum fpi_log_level, const char *component, const char *function,
-	const char *format, ...);
-
-#ifndef FP_COMPONENT
-#define FP_COMPONENT NULL
-#endif
-
-#define _fpi_log(level, fmt...) fpi_log(level, FP_COMPONENT, __FUNCTION__, fmt)
-
-#define fp_dbg(fmt...) _fpi_log(FPRINT_LOG_LEVEL_DEBUG, fmt)
-#define fp_info(fmt...) _fpi_log(FPRINT_LOG_LEVEL_INFO, fmt)
-#define fp_warn(fmt...) _fpi_log(FPRINT_LOG_LEVEL_WARNING, fmt)
-#define fp_err(fmt...) _fpi_log(FPRINT_LOG_LEVEL_ERROR, fmt)
+#define fp_dbg g_debug
+#define fp_info g_debug
+#define fp_warn g_warning
+#define fp_err g_error
 
 #ifndef NDEBUG
 #define BUG_ON(condition) \

libfprint/poll.c

@@ -19,6 +19,8 @@
 
 #define FP_COMPONENT "poll"
 
+#include "fp_internal.h"
+
 #include <config.h>
 #include <errno.h>
 #include <time.h>
@@ -27,8 +29,6 @@
 #include <glib.h>
 #include <libusb.h>
 
-#include "fp_internal.h"
-
 /**
  * SECTION:events
  * @title: Initialisation and events handling

libfprint/sync.c

@@ -19,11 +19,11 @@
 
 #define FP_COMPONENT "sync"
 
+#include "fp_internal.h"
+
 #include <config.h>
 #include <errno.h>
 
-#include "fp_internal.h"
-
 struct sync_open_data {
 	struct fp_dev *dev;
 	int status;

meson.build

@@ -9,6 +9,7 @@ project('libfprint', [ 'c', 'cpp' ],
         meson_version: '>= 0.45.0')
 
 add_project_arguments([ '-D_GNU_SOURCE' ], language: 'c')
+add_project_arguments([ '-DG_LOG_DOMAIN="libfprint"' ], language: 'c')
 
 libfprint_conf = configuration_data()