[PATCH 2/3] fastboot: retire strcmp_l1 in favor of str_has_prefix

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

strcmp_l1 is basically str_has_prefix with inverted arguments and a
NULL check.

We don't need the NULL check as cmdbuf and cmd->cmd should always be
non-NULL: The former is the address of an array populated by fastboot
network or USB code and the latter is a pointer to a string literal.

So let's codify the assumption that cmdbuf is not NULL into the
prototype and replace strcmp_l1 with str_has_prefix. This has the added
benefit that str_has_prefix returns the length of the prefix, which
saves us a repeated call to strlen(cmd->cmd);

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
v1 -> v2:
  - new patch
---
 common/fastboot.c  | 14 +++++---------
 include/fastboot.h |  3 ++-
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/common/fastboot.c b/common/fastboot.c
index e85cc6d8aaf8..dc66d7123b02 100644
--- a/common/fastboot.c
+++ b/common/fastboot.c
@@ -287,13 +287,6 @@ static void cb_reboot(struct fastboot *fb, const char *cmd)
 	restart_machine();
 }
 
-static int strcmp_l1(const char *s1, const char *s2)
-{
-	if (!s1 || !s2)
-		return -1;
-	return strncmp(s1, s2, strlen(s1));
-}
-
 static void cb_getvar(struct fastboot *fb, const char *cmd)
 {
 	struct fb_variable *var;
@@ -815,10 +808,13 @@ static void fb_run_command(struct fastboot *fb, const char *cmdbuf,
 	console_countdown_abort("fastboot");
 
 	for (i = 0; i < num_commands; i++) {
+		size_t cmdlen;
+
 		cmd = &cmds[i];
 
-		if (!strcmp_l1(cmd->cmd, cmdbuf)) {
-			cmd->cb(fb, cmdbuf + strlen(cmd->cmd));
+		cmdlen = str_has_prefix(cmdbuf, cmd->cmd);
+		if (cmdlen) {
+			cmd->cb(fb, cmdbuf + cmdlen);
 
 			return;
 		}
diff --git a/include/fastboot.h b/include/fastboot.h
index cd415847e348..4b2fdf3190b2 100644
--- a/include/fastboot.h
+++ b/include/fastboot.h
@@ -87,7 +87,8 @@ int fastboot_tx_print(struct fastboot *fb, enum fastboot_msg_type type,
 		      const char *fmt, ...);
 void fastboot_start_download_generic(struct fastboot *fb);
 void fastboot_download_finished(struct fastboot *fb);
-void fastboot_exec_cmd(struct fastboot *fb, const char *cmdbuf);
+void fastboot_exec_cmd(struct fastboot *fb, const char *cmdbuf)
+        __attribute__((nonnull));
 void fastboot_abort(struct fastboot *fb);
 
 #endif
-- 
2.39.2