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>

1 files changed, 2 insertions, 4 deletions

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);