ssh: make number of retries configurable

sys/man/1/ssh

@@ -60,6 +60,13 @@ This can be disabled with the
 .B -R
 option.
 .PP
+If
+.I keyboard-interactive
+authentication fails, by default it is retried three times.
+The number of tries can be changed with
+.BR -T .
+Setting it to zero disables keyboard-interactive authentication.
+.PP
 The
 .B -d
 option enables debug output.

sys/src/cmd/ssh.c

@@ -52,9 +52,7 @@ enum {
 	WinPackets = 8,		// (1<<15) * 8 = 256K
 };
 
-enum {
-	MaxPwTries = 3 // retry this often for keyboard-interactive
-};
+int MaxPwTries = 3; // retry this often for keyboard-interactive
 
 typedef struct
 {
@@ -1152,6 +1150,10 @@ main(int argc, char *argv[])
 	case 't':
 		thumbfile = EARGF(usage());
 		break;
+	case 'T':
+		MaxPwTries = strtol(EARGF(usage()), &s, 0);
+		if(*s != 0) usage();
+		break;
 	} ARGEND;
 
 	if(argc == 0)