[PATCH v3 12/13] env: Simplify env_match() and inline into env_get_f()

["Marek Behún" <kabel@kernel.org>]

From: Marek Behún <marek.behun@nic.cz>

In the past the env_match() function was used to match envs with
- name, i.e. string "name"
- variable assignment, i.e. string "name=other_value"

The latter is not the case anymore, since the env_match() function is
now used only in env_get_f(), and so we can simplify the function into
a simple strncmp() with an additional comparison to '='.

Let's do this, and since the resulting function is quite simple, let's
also inline its code into env_get_f().

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
 cmd/nvedit.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index ffcfb55f10..272d0c7718 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -706,28 +706,19 @@ char *from_env(const char *envvar)
 	return ret;
 }
 
-static const char *env_match(const char *p, const char *s1)
-{
-	while (*s1 == *p++)
-		if (*s1++ == '=')
-			return p;
-
-	if (*s1 == '\0' && p[-1] == '=')
-		return p;
-
-	return NULL;
-}
-
 /*
  * Look up variable from environment for restricted C runtime env.
  */
 int env_get_f(const char *name, char *buf, unsigned len)
 {
 	const char *env, *p, *end;
+	size_t name_len;
 
 	if (name == NULL || *name == '\0')
 		return -1;
 
+	name_len = strlen(name);
+
 	if (gd->env_valid == ENV_INVALID)
 		env = (const char *)default_environment;
 	else
@@ -741,9 +732,9 @@ int env_get_f(const char *name, char *buf, unsigned len)
 			if (end - env >= CONFIG_ENV_SIZE)
 				return -1;
 
-		value = env_match(p, name);
-		if (value == NULL)
+		if (strncmp(name, p, name_len) || p[name_len] != '=')
 			continue;
+		value = &p[name_len + 1];
 
 		res = end - value;
 		memcpy(buf, value, min(len, res + 1));
-- 
2.32.0