FTR - though I'm too late to the party:

This also fixes a null pointer exception when running of_diff with invalid arguments: https://lore.barebox.org/barebox/[email protected]/

Tested-by: Johannes Zink <[email protected]>

On 6/8/23 15:40, Ahmad Fatoum wrote:
The error check and message is duplicated for each argument and
could be unified if we move it to get_tree instead.

While at it, we limit argc to exactly 3 in case we want to add options
in the future.

Signed-off-by: Ahmad Fatoum <[email protected]>
---
  commands/of_diff.c | 55 ++++++++++++++++------------------------------
  drivers/of/base.c  |  3 +++
  2 files changed, 22 insertions(+), 36 deletions(-)

diff --git a/commands/of_diff.c b/commands/of_diff.c
index 19a4a26d2012..ff3d46c7f530 100644
--- a/commands/of_diff.c
+++ b/commands/of_diff.c
@@ -17,60 +17,43 @@ static struct device_node *get_tree(const char *filename, 
struct device_node *ro
  {
        struct device_node *node;
+ if (!root)
+               root = ERR_PTR(-ENOENT);
+
        if (!strcmp(filename, "-")) {
-               node = of_get_root_node();
-               if (!node)
-                       return ERR_PTR(-ENOENT);
-
-               return of_dup(node);
-       }
-
-       if (!strcmp(filename, "+")) {
-               node = of_get_root_node();
-               if (!node)
-                       return ERR_PTR(-ENOENT);
-
                node = of_dup(root);
-
-               of_fix_tree(node);
-
-               return node;
+       } else if (!strcmp(filename, "+")) {
+               node = of_dup(root);
+               if (!IS_ERR(node))
+                       of_fix_tree(node);
+       } else {
+               node = of_read_file(filename);
        }
- return of_read_file(filename);
+       if (IS_ERR(node))
+               printf("Cannot read %s: %pe\n", filename, node);
+
+       return node;
  }
static int do_of_diff(int argc, char *argv[])
  {
-       int ret = 0;
+       int ret = COMMAND_ERROR;
        struct device_node *a, *b, *root;
- if (argc < 3)
+       if (argc != 3)
                return COMMAND_ERROR_USAGE;
root = of_get_root_node();
        a = get_tree(argv[1], root);
        b = get_tree(argv[2], root);
- if (IS_ERR(a)) {
-               printf("Cannot read %s: %pe\n", argv[1], a);
-               ret = COMMAND_ERROR;
-               a = NULL;
-               goto out;
-       }
+       if (!IS_ERR(a) && !IS_ERR(b))
+               ret = of_diff(a, b, 0) ? COMMAND_ERROR : COMMAND_SUCCESS;
- if (IS_ERR(b)) {
-               printf("Cannot read %s: %pe\n", argv[2], b);
-               ret = COMMAND_ERROR;
-               b = NULL;
-               goto out;
-       }
-
-       ret = of_diff(a, b, 0) ? COMMAND_ERROR : COMMAND_SUCCESS;
-out:
-       if (a && a != root)
+       if (!IS_ERR(a) && a != root)
                of_delete_node(a);
-       if (b && b != root)
+       if (!IS_ERR(b) && b != root)
                of_delete_node(b);
return ret;
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5da188115547..e3416b5b75a7 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2660,6 +2660,9 @@ struct device_node *of_copy_node(struct device_node 
*parent, const struct device
struct device_node *of_dup(const struct device_node *root)
  {
+       if (IS_ERR_OR_NULL(root))
+               return ERR_CAST(root);
+
        return of_copy_node(NULL, root);
  }

--
Pengutronix e.K.                | Johannes Zink                  |
Steuerwalder Str. 21            | https://www.pengutronix.de/    |
31137 Hildesheim, Germany       | Phone: +49-5121-206917-0       |
Amtsgericht Hildesheim, HRA 2686| Fax:   +49-5121-206917-5555    |


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