[PATCH V2 3/4] Add multi env support to saveenv and loadenv commands.

[Luotao Fu]

saveenv and loadenv commands now support multiple environments. If
CONFIG_MULTI_ENV_HANDLING is turned on. saveenv will try to save the environment
into all available environment backends, while loadenv will load the environment
from the first loadable backend it will find. Also updated the help text.

Signed-off-by: Luotao Fu <l.fu at pengutronix.de>
---
V2 Changes:
* fixed saveenv callback, removed duplicated arg parsing
* fixed loadenv handling, removed unused varaibles.

 commands/loadenv.c |   48 +++++++++++++++++++++++++------
 commands/saveenv.c |   80 +++++++++++++++++++++++++++++++++++----------------
 2 files changed, 94 insertions(+), 34 deletions(-)

diff --git a/commands/loadenv.c b/commands/loadenv.c
index 3da67d9..122a362 100644
--- a/commands/loadenv.c
+++ b/commands/loadenv.c
@@ -26,31 +26,61 @@
 #include <common.h>
 #include <command.h>
 #include <environment.h>
+#include <fs.h>
+#include <linux/stat.h>
 
 static int do_loadenv(struct command *cmdtp, int argc, char *argv[])
 {
-	char *filename, *dirname;
+	char *dirname;
+	int rc = 0;
+#ifdef CONFIG_MULTI_ENV_HANDLING
+	char file[9 + 5];	/* '/dev/env.....' */
+	int i = 0;
+	struct stat file_info;
+#endif
 
 	if (argc < 3)
 		dirname = "/env";
 	else
 		dirname = argv[2];
 
-	if (argc < 2)
-		filename = "/dev/env0";
-	else
-		filename = argv[1];
-	printf("loading environment from %s\n", filename);
+	if (argc > 1) {
+		rc = envfs_load(argv[1], dirname, NULL);
+		return rc ? 1 : 0;
+	}
+
+#ifdef CONFIG_MULTI_ENV_HANDLING
+	/* default filename, loop over all /dev/env[number] till one succeeds */
+	while (1) {
+		sprintf(file, "/dev/env%d", i);
+
+		if (stat(file, &file_info) != 0)
+			break;
+
+		rc = envfs_load(file, dirname, NULL);
+		if (!rc)
+			break;
+		i++;
+	}
+#else
+	rc = envfs_load("/dev/env0", dirname, NULL);
+#endif
 
-	return envfs_load(filename, dirname, NULL);
+	return rc ? 1 : 0;
 }
 
 static const __maybe_unused char cmd_loadenv_help[] =
 "Usage: loadenv [ENVFS] [DIRECTORY]\n"
 "Load the persistent storage contained in <envfs> to the directory\n"
 "<directory>.\n"
-"If ommitted <directory> defaults to /env and <envfs> defaults to /dev/env0.\n"
-"Note that envfs can only handle files. Directories are skipped silently.\n";
+#ifdef CONFIG_MULTI_ENV_HANDLING
+"If ommitted <directory> defaults the command will scan for available"
+" environment backend storages, if more than one of such storages are"
+" available, the environment will try to load the environment from the"
+" loadable backend in ascending order (env0 -> env1).\n";
+#else
+"If ommitted <directory> defaults to /env and <envfs> defaults to /dev/env0.\n";
+#endif
 
 BAREBOX_CMD_START(loadenv)
 	.cmd		= do_loadenv,
diff --git a/commands/saveenv.c b/commands/saveenv.c
index 42ea58f..fa81d80 100644
--- a/commands/saveenv.c
+++ b/commands/saveenv.c
@@ -29,44 +29,33 @@
 #include <fs.h>
 #include <fcntl.h>
 #include <environment.h>
+#include <linux/stat.h>
 
-static int do_saveenv(struct command *cmdtp, int argc, char *argv[])
+static int saveenv(char *filename, char *dirname)
 {
 	int ret, fd;
-	char *filename, *dirname;
 
 	printf("saving environment\n");
-	if (argc < 3)
-		dirname = "/env";
-	else
-		dirname = argv[2];
-	if (argc < 2)
-		filename = "/dev/env0";
-	else
-		filename = argv[1];
 
 	fd = open(filename, O_WRONLY | O_CREAT);
 	if (fd < 0) {
 		printf("could not open %s: %s\n", filename, errno_str());
-		return 1;
+		ret = -ENODEV;
+		goto out_ret;
 	}
 
 	ret = protect(fd, ~0, 0, 0);
-
 	/* ENOSYS is no error here, many devices do not need it */
 	if (ret && errno != -ENOSYS) {
 		printf("could not unprotect %s: %s\n", filename, errno_str());
-		close(fd);
-		return 1;
+		goto out_close;
 	}
 
 	ret = erase(fd, ~0, 0);
-
 	/* ENOSYS is no error here, many devices do not need it */
 	if (ret && errno != -ENOSYS) {
 		printf("could not erase %s: %s\n", filename, errno_str());
-		close(fd);
-		return 1;
+		goto out_close;
 	}
 
 	close(fd);
@@ -74,23 +63,58 @@ static int do_saveenv(struct command *cmdtp, int argc, char *argv[])
 	ret = envfs_save(filename, dirname);
 	if (ret) {
 		printf("saveenv failed\n");
-		goto out;
+		goto out_ret;
 	}
 
 	fd = open(filename, O_WRONLY | O_CREAT);
-
 	ret = protect(fd, ~0, 0, 1);
-
 	/* ENOSYS is no error here, many devices do not need it */
 	if (ret && errno != -ENOSYS) {
 		printf("could not protect %s: %s\n", filename, errno_str());
-		close(fd);
-		return 1;
+		goto out_close;
 	}
 
 	ret = 0;
-out:
+
+out_close:
 	close(fd);
+out_ret:
+	return ret;
+}
+
+static int do_saveenv(struct command *cmdtp, int argc, char *argv[])
+{
+	int ret = 0;
+	char *dirname;
+#ifdef CONFIG_MULTI_ENV_HANDLING
+	int i = 0;
+	char file[9 + 5];
+	struct stat file_info;
+#endif
+
+	printf("saving environment\n");
+	if (argc < 3)
+		dirname = "/env";
+	else
+		dirname = argv[2];
+
+	if (argc > 1)
+		return saveenv(argv[1], dirname);
+#ifdef CONFIG_MULTI_ENV_HANDLING
+	/* default filename, save environment to all /dev/env[number] */
+	while (1) {
+		sprintf(file, "/dev/env%d", i);
+		if (stat(file, &file_info))
+			break;
+
+		ret |= saveenv(file, dirname);
+
+		i++;
+	}
+#else
+	ret = saveenv("/dev/env0", dirname);
+#endif
+
 	return ret;
 }
 
@@ -98,8 +122,14 @@ static const __maybe_unused char cmd_saveenv_help[] =
 "Usage: saveenv [<envfs>] [<directory>]\n"
 "Save the files in <directory> to the persistent storage device <envfs>.\n"
 "<envfs> is normally a block in flash, but could be any other file.\n"
-"If ommitted <directory> defaults to /env and <envfs> defaults to /dev/env0.\n"
-"Note that envfs can only handle files. Directories are skipped silently.\n";
+#ifdef CONFIG_MULTI_ENV_HANDLING
+"If ommitted <directory> defaults the command will scan for available"
+" environment backend storages, if more than one of such storages are"
+" available, the environment will be stored into all of them ascending"
+" order (env0 -> env1).\n";
+#else
+"If ommitted <directory> defaults to /env and <envfs> defaults to /dev/env0.\n";
+#endif
 
 BAREBOX_CMD_START(saveenv)
 	.cmd		= do_saveenv,
-- 
1.7.1