cmd: Add -s flag to printenv -e for sorted output

Add support for sorting EFI variables by name when using printenv -e.
The -s flag sorts variables alphabetically before display, useful when
dealing with large numbers of variables.

Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>

Series-to: concept
Series-cc: heinrich
Cover-letter:
efi: Improvements to env print -e
Printing EFI variables can be quite verbose, with many hundreds of lines
of text. Part of this is because GUIDs and hex dumps are included. It
can also be hard to find a few variables visually in an unsorted list.

This series makes the feature more user-friendly:
- Puts verbose output behind a -v flag, so that 'env print -e' behaves
  more like 'env print'
- Adds a -s option to sort the list
END
Series-links: 1:15

cmd/nvedit_efi.c

@@ -15,6 +15,7 @@
 #include <malloc.h>
 #include <mapmem.h>
 #include <rtc.h>
+#include <sort.h>
 #include <u-boot/uuid.h>
 #include <linux/kernel.h>
 
@@ -142,6 +143,21 @@ out:
 	return result;
 }
 
+/**
+ * var_info_cmp() - compare two var_info structures by name
+ *
+ * @a: First var_info structure
+ * @b: Second var_info structure
+ * Return: comparison result for qsort
+ */
+static int var_info_cmp(const void *a, const void *b)
+{
+	const struct var_info *va = a;
+	const struct var_info *vb = b;
+
+	return u16_strcmp(va->name, vb->name);
+}
+
 /**
  * efi_dump_var_all() - show information about all the UEFI variables
  *
@@ -150,12 +166,14 @@ out:
  * @guid_p:	GUID to filter by, or NULL for all
  * @verbose:	if true, show detailed information
  * @nodump:	if true, don't show hexadecimal dump
+ * @sort:	if true, sort variables by name before printing
  * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
  *
  * Show information encoded in all the UEFI variables
  */
 static int efi_dump_var_all(int argc,  char *const argv[],
-			    const efi_guid_t *guid_p, bool verbose, bool nodump)
+			    const efi_guid_t *guid_p, bool verbose, bool nodump,
+			    bool sort)
 {
 	efi_uintn_t buf_size, size;
 	struct var_info *var;
@@ -209,6 +227,9 @@ static int efi_dump_var_all(int argc,  char *const argv[],
 		goto done;
 	}
 
+	if (sort && vars.count > 1)
+		qsort(vars.data, vars.count, sizeof(struct var_info), var_info_cmp);
+
 	alist_for_each(var, &vars)
 		efi_dump_single_var(var->name, &var->guid, verbose, nodump);
 
@@ -233,10 +254,11 @@ done:
  * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
  *
  * This function is for "env print -e" or "printenv -e" command:
- *   => env print -e [-v] [-guid <guid> | -all] [var [...]]
+ *   => env print -e [-v] [-s] [-guid <guid> | -all] [var [...]]
  * If one or more variable names are specified, show information
  * named UEFI variables, otherwise show all the UEFI variables.
  * By default, only variable names are shown. Use -v for verbose output.
+ * Use -s to sort variables by name.
  */
 int do_env_print_efi(struct cmd_tbl *cmdtp, int flag, int argc,
 		     char *const argv[])
@@ -245,6 +267,7 @@ int do_env_print_efi(struct cmd_tbl *cmdtp, int flag, int argc,
 	efi_guid_t guid;
 	bool verbose = false;
 	bool nodump = false;
+	bool sort = false;
 	efi_status_t ret;
 
 	/* Initialize EFI drivers */
@@ -270,13 +293,15 @@ int do_env_print_efi(struct cmd_tbl *cmdtp, int flag, int argc,
 			nodump = true;
 		} else if (!strcmp(argv[0], "-v")) {
 			verbose = true;
+		} else if (!strcmp(argv[0], "-s")) {
+			sort = true;
 		} else {
 			return CMD_RET_USAGE;
 		}
 	}
 
 	/* enumerate and show all UEFI variables */
-	return efi_dump_var_all(argc, argv, guid_p, verbose, nodump);
+	return efi_dump_var_all(argc, argv, guid_p, verbose, nodump, sort);
 }
 
 /**