Tcl exception codes cleanup, shutdown command amendments

This patch might influence openocd Tcl commands behaviour in subtle
ways, please give it a nice testing.

The idea is that if an OpenOCD Tcl command returns an error, an
exception is raised, and then the return code is propogated all the
way up (or to the "catch" if present). This allows to detect
"shutdown" which is not actually an error but has to raise an
exception to stop execution of the commands that follow it in the
script.

openocd_thread special-cases shutdown because it should then terminate
OpenOCD with a success error code, unless shutdown was called with an
optional "error" argument which means terminate with a non-zero exit
code.

Change-Id: I7b6fa8a2e24c947dc45d8def0008b4b007c478b3
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2600
Tested-by: jenkins
Reviewed-by: Juha Niskanen <juha.niskanen@haltian.com>
Reviewed-by: Jens Bauer <jens@gpio.dk>
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

6 files changed, 48 insertions, 30 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 4bec637f..e418e050 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -6486,8 +6486,10 @@ Useful in connection with script files
 (@command{script} command and @command{target_name} configuration).
 @end deffn
 
-@deffn Command shutdown
-Close the OpenOCD daemon, disconnecting all clients (GDB, telnet, other).
+@deffn Command shutdown [@option{error}]
+Close the OpenOCD daemon, disconnecting all clients (GDB, telnet,
+other). If option @option{error} is used, OpenOCD will return a
+non-zero exit code to the parent process.
 @end deffn
 
 @anchor{debuglevel}
diff --git a/src/flash/startup.tcl b/src/flash/startup.tcl
index 7a96a3e3..fbb8d8ee 100644
--- a/src/flash/startup.tcl
+++ b/src/flash/startup.tcl
@@ -8,8 +8,8 @@
 
 proc program_error {description exit} {
 	if {$exit == 1} {
-	        echo $description
-		shutdown
+		echo $description
+		shutdown error
 	}
 
 	error $description
diff --git a/src/helper/command.c b/src/helper/command.c
index 9d19cff4..a0aa9e85 100644
--- a/src/helper/command.c
+++ b/src/helper/command.c
@@ -121,7 +121,7 @@ static int command_retval_set(Jim_Interp *interp, int retval)
 	if (return_retval != NULL)
 		*return_retval = retval;
 
-	return (retval == ERROR_OK) ? JIM_OK : JIM_ERR;
+	return (retval == ERROR_OK) ? JIM_OK : retval;
 }
 
 extern struct command_context *global_cmd_ctx;
@@ -659,24 +659,7 @@ int command_run_line(struct command_context *context, char *line)
 		}
 		Jim_DeleteAssocData(interp, "context");
 	}
-	if (retcode == JIM_ERR) {
-		if (retval == ERROR_COMMAND_CLOSE_CONNECTION) {
-			/* Shutdown request is not an error */
-			return ERROR_OK;
-		} else {
-			/* We do not print the connection closed error message */
-			Jim_MakeErrorMessage(interp);
-			LOG_USER("%s", Jim_GetString(Jim_GetResult(interp), NULL));
-		}
-		if (retval == ERROR_OK) {
-			/* It wasn't a low level OpenOCD command that failed */
-			return ERROR_FAIL;
-		}
-		return retval;
-	} else if (retcode == JIM_EXIT) {
-		/* ignore.
-		 * exit(Jim_GetExitCode(interp)); */
-	} else {
+	if (retcode == JIM_OK) {
 		const char *result;
 		int reslen;
 
@@ -696,7 +679,22 @@ int command_run_line(struct command_context *context, char *line)
 			LOG_USER_N("\n");
 		}
 		retval = ERROR_OK;
+	} else if (retcode == JIM_EXIT) {
+		/* ignore.
+		 * exit(Jim_GetExitCode(interp)); */
+	} else if (retcode == ERROR_COMMAND_CLOSE_CONNECTION) {
+		return retcode;
+	} else {
+		Jim_MakeErrorMessage(interp);
+		LOG_USER("%s", Jim_GetString(Jim_GetResult(interp), NULL));
+
+		if (retval == ERROR_OK) {
+			/* It wasn't a low level OpenOCD command that failed */
+			return ERROR_FAIL;
+		}
+		return retval;
 	}
+
 	return retval;
 }
 
diff --git a/src/helper/startup.tcl b/src/helper/startup.tcl
index 926d26b6..4ca2cabc 100644
--- a/src/helper/startup.tcl
+++ b/src/helper/startup.tcl
@@ -16,10 +16,12 @@ proc exit {} {
 proc ocd_bouncer {name args} {
 	set cmd [format "ocd_%s" $name]
 	set type [eval ocd_command type $cmd $args]
+	set errcode error
 	if {$type == "native"} {
 		return [eval $cmd $args]
 	} else {if {$type == "simple"} {
-		if {[catch {eval $cmd $args}] == 0} {
+		set errcode [catch {eval $cmd $args}]
+		if {$errcode == 0} {
 			return ""
 		} else {
 			# 'classic' commands output error message as part of progress output
@@ -32,7 +34,7 @@ proc ocd_bouncer {name args} {
 	} else {
 		set errmsg [format "invalid subcommand \"%s\"" $args]
 	}}}
-	return -code error $errmsg
+	return -code $errcode $errmsg
 }
 
 # Try flipping / and \ to find file if the filename does not
diff --git a/src/openocd.c b/src/openocd.c
index b0dd21ab..4d4dc2c8 100644
--- a/src/openocd.c
+++ b/src/openocd.c
@@ -283,7 +283,9 @@ static int openocd_thread(int argc, char *argv[], struct command_context *cmd_ct
 		return ERROR_FAIL;
 
 	ret = parse_config_file(cmd_ctx);
-	if (ret != ERROR_OK)
+	if (ret == ERROR_COMMAND_CLOSE_CONNECTION)
+		return ERROR_OK;
+	else if (ret != ERROR_OK)
 		return ERROR_FAIL;
 
 	ret = server_init(cmd_ctx);
@@ -296,9 +298,15 @@ static int openocd_thread(int argc, char *argv[], struct command_context *cmd_ct
 			return ERROR_FAIL;
 	}
 
-	server_loop(cmd_ctx);
+	ret = server_loop(cmd_ctx);
+
+	int last_signal = server_quit();
+	if (last_signal != ERROR_OK)
+		return last_signal;
 
-	return server_quit();
+	if (ret != ERROR_OK)
+		return ERROR_FAIL;
+	return ERROR_OK;
 }
 
 /* normally this is the main() function entry, but if OpenOCD is linked
diff --git a/src/server/server.c b/src/server/server.c
index 73d8b5b6..7e90d89f 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -44,7 +44,8 @@
 
 static struct service *services;
 
-/* shutdown_openocd == 1: exit the main event loop, and quit the debugger */
+/* shutdown_openocd == 1: exit the main event loop, and quit the
+ * debugger; 2: quit with non-zero return code */
 static int shutdown_openocd;
 
 /* store received signal to exit application by killing ourselves */
@@ -499,7 +500,7 @@ int server_loop(struct command_context *command_context)
 #endif
 	}
 
-	return ERROR_OK;
+	return shutdown_openocd != 2 ? ERROR_OK : ERROR_FAIL;
 }
 
 #ifdef _WIN32
@@ -608,6 +609,13 @@ COMMAND_HANDLER(handle_shutdown_command)
 
 	shutdown_openocd = 1;
 
+	if (CMD_ARGC == 1) {
+		if (!strcmp(CMD_ARGV[0], "error")) {
+			shutdown_openocd = 2;
+			return ERROR_FAIL;
+		}
+	}
+
 	return ERROR_COMMAND_CLOSE_CONNECTION;
 }