bootstd: Add support for updating elements of the cmdline

Add a bootflow command to update the command line more easily. This allows
changing a particular parameter rather than editing a very long strings.
It is also easier to handle with scripting.

The new 'bootflow cmdline' command allows getting and setting single
parameters.

Fix up the example output while we are here, since there are a few new
items.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/include/bootflow.h b/include/bootflow.h
index 8db875adf6..7a8595f3df 100644
--- a/include/bootflow.h
+++ b/include/bootflow.h
@@ -484,4 +484,46 @@ int bootflow_menu_run(struct bootstd_priv *std, bool text_mode,
 int cmdline_set_arg(char *buf, int maxlen, const char *cmdline,
 		    const char *set_arg, const char *new_val, int *posp);
 
+/**
+ * bootflow_cmdline_set_arg() - Set a single argument for a bootflow
+ *
+ * Update the allocated cmdline and set the bootargs variable
+ *
+ * @bflow: Bootflow to update
+ * @arg: Argument to update (e.g. "console")
+ * @val: Value to set (e.g. "ttyS2") or NULL to delete the argument if present,
+ * "" to set it to an empty value (e.g. "console=") and BOOTFLOWCL_EMPTY to add
+ * it without any value ("initrd")
+ * @set_env: true to set the "bootargs" environment variable too
+ *
+ * Return: 0 if OK, -ENOMEM if out of memory
+ */
+int bootflow_cmdline_set_arg(struct bootflow *bflow, const char *arg,
+			     const char *val, bool set_env);
+
+/**
+ * cmdline_get_arg() - Read an argument from a cmdline
+ *
+ * @cmdline: Command line to read, in the form:
+ *
+ *	fred mary= jane=123 john="has spaces"
+ * @arg: Argument to read (may or may not exist)
+ * @posp: Returns position of argument (after any leading quote) if present
+ * Return: Length of argument value excluding quotes if found, -ENOENT if not
+ * found
+ */
+int cmdline_get_arg(const char *cmdline, const char *arg, int *posp);
+
+/**
+ * bootflow_cmdline_get_arg() - Read an argument from a cmdline
+ *
+ * @bootflow: Bootflow to read from
+ * @arg: Argument to read (may or may not exist)
+ * @valp: Returns a pointer to the argument (after any leading quote) if present
+ * Return: Length of argument value excluding quotes if found, -ENOENT if not
+ * found
+ */
+int bootflow_cmdline_get_arg(struct bootflow *bflow, const char *arg,
+			     const char **val);
+
 #endif