shell: Added assert

Assert to check columns. Averts a potential divide by zero

Signed-off-by: Kristoffer Rist Skøien <kristoffer.skoien@nordicsemi.no>

subsys/shell/Kconfig

@@ -91,6 +91,7 @@ config SHELL_PRINTF_BUFF_SIZE
 
 config SHELL_DEFAULT_TERMINAL_WIDTH
 	int "Default terminal width"
+	range 1 $(UINT16_MAX)
 	default 80
 	help
 	  Default terminal width is used to break lines.

subsys/shell/shell.c

@@ -141,6 +141,7 @@ static void tab_item_print(const struct shell *sh, const char *option,
 
 	columns = (sh->ctx->vt100_ctx.cons.terminal_wid
 			- z_shell_strlen(tab)) / longest_option;
+	__ASSERT_NO_MSG(columns != 0);
 	diff = longest_option - z_shell_strlen(option);
 
 	if (sh->ctx->vt100_ctx.printed_cmd++ % columns == 0U) {

subsys/shell/shell_cmds.c

@@ -69,9 +69,6 @@
 /* 10 == {esc, [, 2, 5, 0, ;, 2, 5, 0, '\0'} */
 #define SHELL_CURSOR_POSITION_BUFFER	(10u)
 
-#define SHELL_DEFAULT_TERMINAL_WIDTH 80
-#define SHELL_DEFAULT_TERMINAL_HEIGHT 24
-
 /* Function reads cursor position from terminal. */
 static int cursor_position_get(const struct shell *sh, uint16_t *x, uint16_t *y)
 {
@@ -408,8 +405,8 @@ static int cmd_resize_default(const struct shell *sh,
 	ARG_UNUSED(argv);
 
 	Z_SHELL_VT100_CMD(sh, SHELL_VT100_SETCOL_80);
-	sh->ctx->vt100_ctx.cons.terminal_wid = SHELL_DEFAULT_TERMINAL_WIDTH;
-	sh->ctx->vt100_ctx.cons.terminal_hei = SHELL_DEFAULT_TERMINAL_HEIGHT;
+	sh->ctx->vt100_ctx.cons.terminal_wid = CONFIG_SHELL_DEFAULT_TERMINAL_WIDTH;
+	sh->ctx->vt100_ctx.cons.terminal_hei = CONFIG_SHELL_DEFAULT_TERMINAL_HEIGHT;
 
 	return 0;
 }