Add no-return attribute to usage() style functions

A common pattern in command line processing is having a usage()
function that prints out how to use the command line options and
then terminates.

The function is typically used inside a switch block for command
line options like `-h' or unknown options. In a lot of places, the
break keyword is omitted, because the function exits anyway. However,
this triggers gcc warnings about implicit fall-through.

Rather than adding a phony "/* fall-through */" this patch flags the
usage() style function with a gcc attribute, indicating that they do
not return and removes further superfluous break statements.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

13 files changed, 19 insertions, 19 deletions

diff --git a/include/common.h b/include/common.h
index d609257..2ce5d22 100644
--- a/include/common.h
+++ b/include/common.h
@@ -129,6 +129,13 @@ extern "C" {
 	fprintf(stderr, "%s: warning!: " fmt "\n", PROGRAM_NAME, ##__VA_ARGS__); \
 } while(0)
 
+/* for tagging functions that always exit */
+#if defined(__GNUC__) || defined(__clang__)
+	#define NORETURN __attribute__((noreturn))
+#else
+	#define NORETURN
+#endif
+
 /**
  * prompt the user for confirmation
  */
diff --git a/misc-utils/flash_unlock.c b/misc-utils/flash_unlock.c
index 5a3aac5..fbbfa51 100644
--- a/misc-utils/flash_unlock.c
+++ b/misc-utils/flash_unlock.c
@@ -36,7 +36,7 @@ static const char *flash_msg[] = {
 	[ REQUEST_ISLOCKED ]	= "check lock status",
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fprintf(status ? stderr : stdout,
 		"Utility to lock, unlock, or check the lock status of the flash.\n"
@@ -88,7 +88,6 @@ static void process_args(int argc, char *argv[])
 		switch (c) {
 		case 'h':
 			usage(EXIT_SUCCESS);
-			break;
 		case 'i':
 			req = REQUEST_ISLOCKED;
 			req_set++;
@@ -106,7 +105,6 @@ static void process_args(int argc, char *argv[])
 			exit(0);
 		default:
 			usage(EXIT_FAILURE);
-			break;
 		}
 	}
 
diff --git a/misc-utils/flashcp.c b/misc-utils/flashcp.c
index a35e6fc..0718733 100644
--- a/misc-utils/flashcp.c
+++ b/misc-utils/flashcp.c
@@ -81,7 +81,7 @@ static void log_printf (int level,const char *fmt, ...)
 	fflush (fp);
 }
 
-static void showusage(bool error)
+static NORETURN void showusage(bool error)
 {
 	int level = error ? LOG_ERROR : LOG_NORMAL;
 
diff --git a/misc-utils/mtd_debug.c b/misc-utils/mtd_debug.c
index 90f5d52..d90a968 100644
--- a/misc-utils/mtd_debug.c
+++ b/misc-utils/mtd_debug.c
@@ -339,7 +339,7 @@ static int showinfo(int fd)
 	return 0;
 }
 
-static void showusage(void)
+static NORETURN void showusage(void)
 {
 	fprintf(stderr, "usage: %1$s info <device>\n"
 			"       %1$s read <device> <offset> <len> <dest-filename>\n"
diff --git a/nand-utils/nandtest.c b/nand-utils/nandtest.c
index d5c7369..06dec25 100644
--- a/nand-utils/nandtest.c
+++ b/nand-utils/nandtest.c
@@ -17,7 +17,7 @@
 #include "mtd/mtd-user.h"
 #include "common.h"
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fprintf(status ? stderr : stdout,
 		"usage: %s [OPTIONS] <device>\n\n"
@@ -184,14 +184,12 @@ int main(int argc, char **argv)
 		switch (c) {
 		case 'h':
 			usage(EXIT_SUCCESS);
-			break;
 		case 'V':
 			common_print_version();
 			exit(EXIT_SUCCESS);
 			break;
 		case '?':
 			usage(EXIT_FAILURE);
-			break;
 
 		case 'm':
 			markbad = 1;
diff --git a/nand-utils/nftl_format.c b/nand-utils/nftl_format.c
index ec87604..c8b8b50 100644
--- a/nand-utils/nftl_format.c
+++ b/nand-utils/nftl_format.c
@@ -198,7 +198,7 @@ static int checkbbt(void)
 	return (0);
 }
 
-static void usage(int rc)
+static NORETURN void usage(int rc)
 {
 	fprintf(stderr, "Usage: %s [-ib] <mtddevice> [<start offset> [<size>]]\n", PROGRAM_NAME);
 	exit(rc);
@@ -250,13 +250,11 @@ int main(int argc, char **argv)
 			case 'h':
 			case '?':
 				usage(EXIT_SUCCESS);
-				break;
 			case 'V':
 				display_version();
 				break;
 			default:
 				usage(EXIT_FAILURE);
-				break;
 		}
 	}
 
diff --git a/tests/mtd-tests/flash_readtest.c b/tests/mtd-tests/flash_readtest.c
index bc6874a..c5fabc9 100644
--- a/tests/mtd-tests/flash_readtest.c
+++ b/tests/mtd-tests/flash_readtest.c
@@ -54,7 +54,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
diff --git a/tests/mtd-tests/flash_speed.c b/tests/mtd-tests/flash_speed.c
index d5cedba..0058269 100644
--- a/tests/mtd-tests/flash_speed.c
+++ b/tests/mtd-tests/flash_speed.c
@@ -60,7 +60,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
@@ -100,7 +100,6 @@ static void process_options(int argc, char **argv)
 		switch (c) {
 		case 'h':
 			usage(EXIT_SUCCESS);
-			break;
 		case 'b':
 			if (peb >= 0)
 				goto failmulti;
diff --git a/tests/mtd-tests/flash_stress.c b/tests/mtd-tests/flash_stress.c
index f50c664..249d8cb 100644
--- a/tests/mtd-tests/flash_stress.c
+++ b/tests/mtd-tests/flash_stress.c
@@ -63,7 +63,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
diff --git a/tests/mtd-tests/flash_torture.c b/tests/mtd-tests/flash_torture.c
index 21cedf4..5aad8e0 100644
--- a/tests/mtd-tests/flash_torture.c
+++ b/tests/mtd-tests/flash_torture.c
@@ -67,7 +67,7 @@ static void sighandler(int sig)
 		flags &= ~RUN_FOREVER;
 }
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
diff --git a/tests/mtd-tests/nandbiterrs.c b/tests/mtd-tests/nandbiterrs.c
index 200fe1c..ef987dc 100644
--- a/tests/mtd-tests/nandbiterrs.c
+++ b/tests/mtd-tests/nandbiterrs.c
@@ -85,7 +85,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
diff --git a/tests/mtd-tests/nandpagetest.c b/tests/mtd-tests/nandpagetest.c
index 86c9005..2b16cc9 100644
--- a/tests/mtd-tests/nandpagetest.c
+++ b/tests/mtd-tests/nandpagetest.c
@@ -58,7 +58,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"
diff --git a/tests/mtd-tests/nandsubpagetest.c b/tests/mtd-tests/nandsubpagetest.c
index 04f6c8c..cd7e4e8 100644
--- a/tests/mtd-tests/nandsubpagetest.c
+++ b/tests/mtd-tests/nandsubpagetest.c
@@ -57,7 +57,7 @@ static const struct option options[] = {
 	{ NULL, 0, NULL, 0 },
 };
 
-static void usage(int status)
+static NORETURN void usage(int status)
 {
 	fputs(
 	"Usage: "PROGRAM_NAME" [OPTIONS] <device>\n\n"