Add basic logger (#2263)

include/logger.h

@@ -0,0 +1,65 @@
+/** @file
+    Basic logging, API.
+
+    Copyright (C) 2021 Christian Zuckschwerdt
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+*/
+
+#ifndef INCLUDE_LOGGER_H_
+#define INCLUDE_LOGGER_H_
+
+// Defined in newer <sal.h> for MSVC.
+#ifndef _Printf_format_string_
+#define _Printf_format_string_
+#endif
+
+/// Log levels, copied from and compatible with SoapySDR.
+/// LOG_FATAL, LOG_ERROR, LOG_WARNING are abnormal program states, other levels are normal information.
+/// LOG_FATAL is not actually used, fatal errors usually fprintf and terminate.
+typedef enum log_level {
+    LOG_FATAL    = 1, //!< A fatal error. The application will most likely terminate. This is the highest priority.
+    LOG_CRITICAL = 2, //!< A critical error. The application might not be able to continue running successfully.
+    LOG_ERROR    = 3, //!< An error. An operation did not complete successfully, but the application as a whole is not affected.
+    LOG_WARNING  = 4, //!< A warning. An operation completed with an unexpected result.
+    LOG_NOTICE   = 5, //!< A notice, which is an information with just a higher priority.
+    LOG_INFO     = 6, //!< An informational message, usually denoting the successful completion of an operation.
+    LOG_DEBUG    = 7, //!< A debugging message.
+    LOG_TRACE    = 8, //!< A tracing message. This is the lowest priority.
+} log_level_t;
+
+typedef void (*r_logger_handler)(log_level_t level, char const *src, char const *msg, void *userdata);
+
+/** Set the log handler.
+
+    @param handler the handler to use, NULL to reset to default handler
+    @param userdata user data passed back to the handler
+*/
+void r_logger_set_log_handler(r_logger_handler const handler, void *userdata);
+
+/** Log a message string.
+
+    @param level a log level
+    @param src the log source, typically the function name ("__func__") or a module ("SoapySDR")
+    @param msg a log message
+*/
+void print_log(log_level_t level, char const *src, char const *msg);
+
+/** Log a message format string.
+
+    Be terse, messages should be shorter than 100 and a maximum length of 200 characters.
+
+    @param level a log level
+    @param src the log source, typically the function name ("__func__") or a module ("SoapySDR")
+    @param fmt a log message format string
+*/
+void print_logf(log_level_t level, char const *src, _Printf_format_string_ char const *fmt, ...)
+#if defined(__GNUC__) || defined(__clang__)
+        __attribute__((format(printf, 3, 4)))
+#endif
+        ;
+
+#endif /* INCLUDE_LOGGER_H_ */

include/sdr.h

@@ -204,4 +204,8 @@ int sdr_start(sdr_dev_t *dev, sdr_event_cb_t cb, void *ctx, uint32_t buf_num, ui
 */
 int sdr_stop(sdr_dev_t *dev);
 
+/** Redirect SoapySDR library logging.
+*/
+void sdr_redirect_logging(void);
+
 #endif /* INCLUDE_SDR_H_ */

src/CMakeLists.txt

@@ -20,6 +20,7 @@ add_library(r_433 STATIC
     http_server.c
     jsmn.c
     list.c
+    logger.c
     mongoose.c
     optparse.c
     output_file.c

src/logger.c

@@ -0,0 +1,50 @@
+/** @file
+    Basic logging.
+
+    Copyright (C) 2021 Christian W. Zuckschwerdt <zany@triq.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+*/
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <logger.h>
+
+static r_logger_handler logger_handler = NULL;
+static void *logger_handler_userdata   = NULL;
+
+static void default_handler(log_level_t level, char const *src, char const *msg)
+{
+    (void)level;
+    fprintf(stderr, "%s: %s\n", src, msg);
+}
+
+void r_logger_set_log_handler(r_logger_handler const handler, void *userdata)
+{
+    logger_handler = handler;
+    logger_handler_userdata = userdata;
+}
+
+void print_log(log_level_t level, char const *src, char const *msg)
+{
+    if (logger_handler) {
+        logger_handler(level, src, msg, logger_handler_userdata);
+    }
+    else {
+        default_handler(level, src, msg);
+    }
+}
+
+void print_logf(log_level_t level, char const *src, char const *fmt, ...)
+{
+    char msg[256];
+    va_list ap;
+    va_start(ap, fmt);
+    vsnprintf(msg, sizeof(msg), fmt, ap);
+    va_end(ap);
+    print_log(level, src, msg);
+}

src/rtl_433.c

@@ -1370,6 +1370,7 @@ int main(int argc, char **argv) {
     r_cfg_t *cfg = &g_cfg;
 
     print_version(); // always print the version info
+    sdr_redirect_logging();
 
     r_init_cfg(cfg);
 

src/sdr.c

@@ -19,6 +19,7 @@
 #include "sdr.h"
 #include "r_util.h"
 #include "optparse.h"
+#include "logger.h"
 #include "fatal.h"
 #ifdef RTLSDR
 #include <rtl-sdr.h>
@@ -1645,3 +1646,18 @@ int sdr_stop(sdr_dev_t *dev)
 
     return -1;
 }
+
+#ifdef SOAPYSDR
+static void soapysdr_log_handler(const SoapySDRLogLevel level, const char *message)
+{
+    // Our log levels are compatible with SoapySDR.
+    print_log((log_level_t)level, "SoapySDR", message);
+}
+#endif
+
+void sdr_redirect_logging(void)
+{
+#ifdef SOAPYSDR
+    SoapySDR_registerLogHandler(soapysdr_log_handler);
+#endif
+}