Add --log-file

adsbus/log.c

@@ -1,22 +1,59 @@
 #include <assert.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include "log.h"
+#include "uuid.h"
 
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 
 static FILE *log_stream = NULL;
+static char *log_path = NULL;
+static uint8_t log_id[UUID_LEN];
+
+static void log_rotate() {
+	uint8_t old_log_id[UUID_LEN], new_log_id[UUID_LEN];
+	uuid_gen(new_log_id);
+	log_write('L', log_id, "Switching to new log with ID %s at: %s", new_log_id, log_path);
+	memcpy(old_log_id, log_id, UUID_LEN);
+	memcpy(log_id, new_log_id, UUID_LEN);
+	assert(!fclose(log_stream));
+	log_stream = fopen(log_path, "a");
+	assert(log_stream);
+	log_write('L', log_id, "Log start after switch from log ID %s", old_log_id);
+}
 
 void log_init() {
-	log_stream = fdopen(STDERR_FILENO, "a");
+	int fd = dup(STDERR_FILENO);
+	assert(fd >= 0);
+	log_stream = fdopen(fd, "a");
 	assert(log_stream);
 	setlinebuf(log_stream);
+
+	uuid_gen(log_id);
+	log_write('L', log_id, "Log start");
 }
 
 void log_cleanup() {
+	log_write('L', log_id, "Log end");
 	assert(!fclose(log_stream));
+	if (log_path) {
+		free(log_path);
+		log_path = NULL;
+	}
+}
+
+bool log_reopen(const char *path) {
+	if (log_path) {
+		free(log_path);
+	}
+	log_path = strdup(path);
+	assert(log_path);
+	log_rotate();
+	return true;
 }
 
 void log_write(char type, const uint8_t *id, const char *fmt, ...) {