[PATCH 5/6] kexec: Fix return value build warnings

[geoff@xxxxxxxxxxxxx (Geoff Levand)]

Add a local variable and check return values.

Fixes build warnings like these:

  kexec/fs2dt.c: warning: ignoring return value of ?read?

Signed-off-by: Geoff Levand <geoff at infradead.org> for Huawei, Linaro
---
 kexec/fs2dt.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/kexec/fs2dt.c b/kexec/fs2dt.c
index 1f5b0cf..50e173e 100644
--- a/kexec/fs2dt.c
+++ b/kexec/fs2dt.c
@@ -555,6 +555,7 @@ static void putnode(void)
 	/* Add cmdline to the second kernel.  Check to see if the new
 	 * cmdline has a root=.  If not, use the old root= cmdline.  */
 	if (!strcmp(basename,"chosen/")) {
+		size_t result;
 		size_t cmd_len = 0;
 		char *param = NULL;
 		char filename[MAXPATH];
@@ -636,8 +637,13 @@ static void putnode(void)
 			close(fd);
 			goto no_debug;
 		}
-		read(fd, buff, statbuf.st_size);
+		result = read(fd, buff, statbuf.st_size);
 		close(fd);
+		if (result <= 0) {
+			printf("Unable to stat %s, printing from purgatory is diabled\n",
+														filename);
+			goto no_debug;
+		}
 		strncpy(filename, "/proc/device-tree/", MAXPATH);
 		strncat(filename, buff, MAXPATH);
 		strncat(filename, "/compatible", MAXPATH);
@@ -659,8 +665,8 @@ static void putnode(void)
 			close(fd);
 			goto no_debug;
 		}
-		read(fd, buff, statbuf.st_size);
-		if (!strcmp(buff, "hvterm1") || !strcmp(buff, "hvterm-protocol"))
+		result = read(fd, buff, statbuf.st_size);
+		if (result && (!strcmp(buff, "hvterm1") || !strcmp(buff, "hvterm-protocol")))
 			my_debug = 1;
 		close(fd);
 		free(buff);
-- 
1.8.1.2