From: Marek Behún <marek.behun@nic.cz>
Date: Sun, 17 Oct 2021 15:36:35 +0000 (+0200)
Subject: env: Make return value of env_get_f() behave like sprintf() on success
X-Git-Url: http://git.dujemihanovic.xyz/?a=commitdiff_plain;h=3112ce0ce8195880aec5e9373434a85e21c3e1af;p=u-boot.git

env: Make return value of env_get_f() behave like sprintf() on success

Currently the env_get_f() function's return value behaves weirdly: it
returns the number of bytes written into `buf`, but whether this is
excluding the terminating NULL-byte or including it depends on whether
there was enough space in `buf`.

Change the function to always return the actual length of the value of
the environment variable (excluding the terminating NULL-byte) on
success. This makes it behave like sprintf().

All users of this function in U-Boot are compatible with this change.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index 063cc76282..527b522e9e 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -735,7 +735,7 @@ int env_get_f(const char *name, char *buf, unsigned len)
 
 	for (p = env; *p != '\0'; p = end + 1) {
 		const char *value;
-		int n;
+		int n, res;
 
 		for (end = p; *end != '\0'; ++end)
 			if (end - env >= CONFIG_ENV_SIZE)
@@ -745,11 +745,13 @@ int env_get_f(const char *name, char *buf, unsigned len)
 		if (value == NULL)
 			continue;
 
+		res = end - value;
+
 		/* found; copy out */
 		for (n = 0; n < len; ++n, ++buf) {
 			*buf = *value++;
 			if (*buf == '\0')
-				return n;
+				return res;
 		}
 
 		if (n)
@@ -758,7 +760,7 @@ int env_get_f(const char *name, char *buf, unsigned len)
 		printf("env_buf [%u bytes] too small for value of \"%s\"\n",
 		       len, name);
 
-		return n;
+		return res;
 	}
 
 	return -1;
diff --git a/include/env.h b/include/env.h
index 220ab979d9..ee5e30d036 100644
--- a/include/env.h
+++ b/include/env.h
@@ -120,10 +120,8 @@ char *from_env(const char *envvar);
  * support reading the value (slowly) and some will not.
  *
  * @varname:	Variable to look up
- * @return number of bytes written into @buf, excluding the terminating
- *	NULL-byte if there was enough space in @buf, and including the
- *	terminating NULL-byte if there wasn't enough space, or -1 if the
- *	variable is not found
+ * @return actual length of the variable value excluding the terminating
+ *	NULL-byte, or -1 if the variable is not found
  */
 int env_get_f(const char *name, char *buf, unsigned int len);