loadenv: allow more fine grained environment loading

This implements two new options for the loadenv command:

-s: removes (scrubs) old directory contents to be able to
    create a fresh environment from for example /dev/defaultenv
-n: no overwrite. Do not overwrite existing files. This allows
    to keep parts of the old environment.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 12 insertions, 4 deletions

diff --git a/common/environment.c b/common/environment.c
index 69c4c0aa76..e11cd9dd47 100644
--- a/common/environment.c
+++ b/common/environment.c
@@ -206,7 +206,7 @@ EXPORT_SYMBOL(envfs_save);
  * Note: This function will also be used on the host! See note in the header
  * of this file.
  */
-int envfs_load(char *filename, char *dir)
+int envfs_load(char *filename, char *dir, unsigned flags)
 {
 	struct envfs_super super;
 	void *buf = NULL, *buf_free = NULL;
@@ -316,6 +316,14 @@ int envfs_load(char *filename, char *dir)
 			}
 			free(str);
 		} else {
+			struct stat s;
+
+			if (flags & ENV_FLAG_NO_OVERWRITE &&
+					!stat(str, &s)) {
+				printf("skip %s\n", str);
+				goto skip;
+			}
+
 			fd = open(str, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 			free(str);
 			if (fd < 0) {
@@ -333,7 +341,7 @@ int envfs_load(char *filename, char *dir)
 			}
 			close(fd);
 		}
-
+skip:
 		buf += PAD4(inode_size);
 		size -= headerlen_full + PAD4(inode_size) +
 				sizeof(struct envfs_inode);
diff --git a/common/startup.c b/common/startup.c
index 7bb3c73c12..14409a217d 100644
--- a/common/startup.c
+++ b/common/startup.c
@@ -108,12 +108,12 @@ void start_barebox (void)
 	debug("initcalls done\n");
 
 #ifdef CONFIG_ENV_HANDLING
-	if (envfs_load(default_environment_path, "/env")) {
+	if (envfs_load(default_environment_path, "/env", 0)) {
 #ifdef CONFIG_DEFAULT_ENVIRONMENT
 		printf("no valid environment found on %s. "
 			"Using default environment\n",
 			default_environment_path);
-		envfs_load("/dev/defaultenv", "/env");
+		envfs_load("/dev/defaultenv", "/env", 0);
 #endif
 	}
 #endif