hexdump: Allow ctrl-c to interrupt output

If a long hexdump is initated the user may wish to interrupt it. Add
support for this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/hexdump.h b/include/hexdump.h
index b75e260..f2ca479 100644
--- a/include/hexdump.h
+++ b/include/hexdump.h
@@ -125,6 +125,8 @@
  * @buf: data blob to dump
  * @len: number of bytes in the @buf
  * @ascii: include ASCII after the hex output
+ * Returns: 0 if finished normally, -EINTR if Ctrl-C was pressed, -ENOSYS if not
+ * supported
  *
  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
  * to the stdio, with an optional leading prefix.
@@ -143,8 +145,8 @@
  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
  */
-void print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
-		    int groupsize, const void *buf, size_t len, bool ascii);
+int print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
+		   int groupsize, const void *buf, size_t len, bool ascii);
 
 /**
  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
diff --git a/lib/hexdump.c b/lib/hexdump.c
index a56e108..149c93e 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -125,8 +125,8 @@
 	return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
 }
 
-void print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
-		    int groupsize, const void *buf, size_t len, bool ascii)
+int print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
+		   int groupsize, const void *buf, size_t len, bool ascii)
 {
 	const u8 *ptr = buf;
 	int i, linelen, remaining = len;
@@ -157,7 +157,11 @@
 			printf("%s%s\n", prefix_str, linebuf);
 			break;
 		}
+		if (!IS_ENABLED(CONFIG_SPL_BUILD) && ctrlc())
+			return -EINTR;
 	}
+
+	return 0;
 }
 
 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
@@ -170,9 +174,10 @@
  * Some code in U-Boot copy-pasted from Linux kernel uses both
  * functions below so to keep stuff compilable we keep these stubs here.
  */
-void print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
-		    int groupsize, const void *buf, size_t len, bool ascii)
+int print_hex_dump(const char *prefix_str, int prefix_type, int rowsize,
+		   int groupsize, const void *buf, size_t len, bool ascii)
 {
+	return -ENOSYS;
 }
 
 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,