dummyflasher: Add error check for file read

Print an error message and return if the read from emu_persistent_image
fails.

Change-Id: Icd1a72f9171e547f2081ba4bc53834a17ef7fcab
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1403912
Reviewed-on: https://review.coreboot.org/c/flashrom/+/34845
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67839
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
---
M dummyflasher.c
1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/dummyflasher.c b/dummyflasher.c
index f171128..8c3606e 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -381,8 +381,12 @@
 		if (image_stat.st_size == emu_chip_size) {
 			msg_pdbg("matches.\n");
 			msg_pdbg("Reading %s\n", emu_persistent_image);
-			read_buf_from_file(flashchip_contents, emu_chip_size,
-					   emu_persistent_image);
+			if (read_buf_from_file(flashchip_contents, emu_chip_size,
+					   emu_persistent_image)) {
+				msg_perr("Unable to read %s\n", emu_persistent_image);
+				free(flashchip_contents);
+				return 1;
+			}
 		} else {
 			msg_pdbg("doesn't match.\n");
 		}

