tftp: Replace commented out debug prints with log call

There's a few commented out development/debug prints lingering in the
code that can be useful to enable in order to get some basic insights
into what's going on in the server.

While more work is needed to determine what level of debug prints are
useful, and where they should be placed, introduce a '-d' argument to
tqftpserv and translate these to runtime-conditional prints for now.

Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>

tqftpserv.c

@@ -8,6 +8,7 @@
 #include <fcntl.h>
 #include <libgen.h>
 #include <libqrtr.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -78,9 +79,24 @@ struct tftp_client {
 	uint16_t blk_expected;
 };
 
+static bool tftp_debug;
+
 static struct list_head readers = LIST_INIT(readers);
 static struct list_head writers = LIST_INIT(writers);
 
+static void log_debug(const char *fmt, ...)
+{
+	va_list ap;
+
+	if (!tftp_debug)
+		return;
+
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	fflush(stderr);
+}
+
 static int sanitize_path(const char *path)
 {
 	const char *p;
@@ -180,7 +196,7 @@ static ssize_t tftp_send_data(struct tftp_client *client,
 		send_len = p - buf;
 	}
 
-	// printf("[TQFTP] Sending %zd bytes of DATA\n", send_len);
+	log_debug("[TQFTP] Sending %zd bytes of DATA\n", send_len);
 	return send(client->sock, buf, send_len, 0);
 }
 
@@ -523,7 +539,7 @@ static void handle_rrq(const char *buf, size_t len, struct sockaddr_qrtr *sq)
 		return;
 	}
 
-	// printf("[TQFTP] new reader added\n");
+	log_debug("[TQFTP] new reader added\n");
 
 	list_add(&readers, &client->node);
 
@@ -666,7 +682,7 @@ static void handle_wrq(const char *buf, size_t len, struct sockaddr_qrtr *sq)
 		return;
 	}
 
-	// printf("[TQFTP] new writer added\n");
+	log_debug("[TQFTP] new writer added at %d:%d\n", sq->sq_node, sq->sq_port);
 
 	list_add(&writers, &client->node);
 
@@ -738,7 +754,7 @@ static int handle_reader(struct tftp_client *client)
 	}
 
 	last = buf[2] << 8 | buf[3];
-	// printf("[TQFTP] Got ack for %d\n", last);
+	log_debug("[TQFTP] Got ack for %d from %d:%d\n", last, sq.sq_node, sq.sq_port);
 
 	/* We've sent enough data for rsize already */
 	if (last * client->blksize > client->rsize)
@@ -757,7 +773,7 @@ static int handle_reader(struct tftp_client *client)
 			printf("[TQFTP] Sent block %d failed: %zd\n", block + 1, n);
 			break;
 		}
-		// printf("[TQFTP] Sent block %d of %zd\n", block + 1, n);
+		log_debug("[TQFTP] Sent block %d of %zd to %d:%d\n", block + 1, n, sq.sq_node, sq.sq_port);
 		if (n == 0)
 			break;
 		/* We've sent enough data for rsize already */
@@ -856,6 +872,15 @@ static void client_close_and_free(struct tftp_client *client)
 	free(client);
 }
 
+static void print_usage(void)
+{
+	extern const char *__progname;
+
+	fprintf(stderr, "Usage: %s [-d] [-h]\n", __progname);
+	fprintf(stderr, " -d\tPrint detailed debug information\n");
+	fprintf(stderr, " -h\tPrint this usage info\n");
+}
+
 int main(int argc, char **argv)
 {
 	struct tftp_client *client;
@@ -868,9 +893,29 @@ int main(int argc, char **argv)
 	fd_set rfds;
 	int nfds;
 	int opcode;
+	int opt;
 	int ret;
 	int fd;
 
+	while ((opt = getopt(argc, argv, "dh")) != -1) {
+		switch (opt) {
+		case 'd':
+			tftp_debug = true;
+			break;
+		case 'h':
+			print_usage();
+			return 0;
+		default:
+			print_usage();
+			return 1;
+		}
+	}
+
+	if (optind != argc) {
+		print_usage();
+		return 1;
+	}
+
 	fd = qrtr_open(0);
 	if (fd < 0) {
 		fprintf(stderr, "failed to open qrtr socket\n");
@@ -944,14 +989,14 @@ int main(int argc, char **argv)
 
 				switch (pkt.type) {
 				case QRTR_TYPE_BYE:
-					// fprintf(stderr, "[TQFTP] got bye\n");
+					log_debug("[TQFTP] got bye for %d\n", pkt.node);
 					list_for_each_entry_safe(client, next, &writers, node) {
 						if (client->sq.sq_node == sq.sq_node)
 							client_close_and_free(client);
 					}
 					break;
 				case QRTR_TYPE_DEL_CLIENT:
-					// fprintf(stderr, "[TQFTP] got del_client\n");
+					log_debug("[TQFTP] got del_client for %d:%d\n", pkt.node, pkt.port);
 					list_for_each_entry_safe(client, next, &writers, node) {
 						if (!memcmp(&client->sq, &sq, sizeof(sq)))
 							client_close_and_free(client);
@@ -968,7 +1013,6 @@ int main(int argc, char **argv)
 					handle_rrq(buf, len, &sq);
 					break;
 				case OP_WRQ:
-					// printf("[TQFTP] write\n");
 					handle_wrq(buf, len, &sq);
 					break;
 				case OP_ERROR: