cli: run_commandf(): small fixups

* vsnprintf() can truncate cmd, hence it makes no sense to launch such
command (it's broken). Moreover, it's better to signalize to the caller
about such case (for facilitating debugging or bug hunting).

* Fix kernel-doc warnings:
  include/command.h:264: info: Scanning doc for run_commandf
  include/command.h:268: warning: contents before sections
  include/command.h:271: warning: No description found for return value
                                  of 'run_commandf'

* Add printf-like format attribute to validate at compile-time the format
string against parameters's type.

* Fix compilation error in case of -Wall, -Werror, -Wextra:
error: variable ā€˜iā€™ set but not used [-Werror=unused-but-set-variable]

* Drop extra ret variable.

Signed-off-by: Evgeny Bachinin <EABachinin@sberdevices.ru>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cli.c b/common/cli.c
index 9451e6a..3916a7b 100644
--- a/common/cli.c
+++ b/common/cli.c
@@ -8,6 +8,8 @@
  * JinHua Luo, GuangDong Linux Center, <luo.jinhua@gd-linux.com>
  */
 
+#define pr_fmt(fmt) "cli: %s: " fmt, __func__
+
 #include <common.h>
 #include <bootstage.h>
 #include <cli.h>
@@ -20,6 +22,7 @@
 #include <malloc.h>
 #include <asm/global_data.h>
 #include <dm/ofnode.h>
+#include <linux/errno.h>
 
 #ifdef CONFIG_CMDLINE
 /*
@@ -129,16 +132,26 @@
 int run_commandf(const char *fmt, ...)
 {
 	va_list args;
-	char cmd[128];
-	int i, ret;
+	int nbytes;
 
 	va_start(args, fmt);
-	i = vsnprintf(cmd, sizeof(cmd), fmt, args);
+	/*
+	 * Limit the console_buffer space being used to CONFIG_SYS_CBSIZE,
+	 * because its last byte is used to fit the replacement of \0 by \n\0
+	 * in underlying hush parser
+	 */
+	nbytes = vsnprintf(console_buffer, CONFIG_SYS_CBSIZE, fmt, args);
 	va_end(args);
 
-	ret = run_command(cmd, 0);
-
-	return ret;
+	if (nbytes < 0) {
+		pr_debug("I/O internal error occurred.\n");
+		return -EIO;
+	} else if (nbytes >= CONFIG_SYS_CBSIZE) {
+		pr_debug("'fmt' size:%d exceeds the limit(%d)\n",
+			 nbytes, CONFIG_SYS_CBSIZE);
+		return -ENOSPC;
+	}
+	return run_command(console_buffer, 0);
 }
 
 /****************************************************************************/