tools/hv: Check for read/write errors

hv_kvp_daemon currently does not check whether fread() or fwrite()
succeed.  Add the necessary checks.  Also, remove the incorrect use of
feof() before fread().

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 19 insertions, 3 deletions

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 01b3ca583baf..3922abc0daef 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -160,7 +160,12 @@ static void kvp_update_file(int pool)
                                 sizeof(struct kvp_record),
                                 kvp_file_info[pool].num_records, filep);
 
-        fclose(filep);
+        if (ferror(filep) || fclose(filep)) {
+                kvp_release_lock(pool);
+                syslog(LOG_ERR, "Failed to write file, pool: %d", pool);
+                exit(EXIT_FAILURE);
+        }
+
         kvp_release_lock(pool);
 }
 
@@ -181,12 +186,17 @@ static void kvp_update_mem_state(int pool)
                 syslog(LOG_ERR, "Failed to open file, pool: %d", pool);
                 exit(EXIT_FAILURE);
         }
-        while (!feof(filep)) {
+        for (;;) {
                 readp = &record[records_read];
                 records_read += fread(readp, sizeof(struct kvp_record),
                                         ENTRIES_PER_BLOCK * num_blocks,
                                         filep);
 
+                if (ferror(filep)) {
+                        syslog(LOG_ERR, "Failed to read file, pool: %d", pool);
+                        exit(EXIT_FAILURE);
+                }
+
                 if (!feof(filep)) {
                         /*
                          * We have more data to read.
@@ -249,12 +259,18 @@ static int kvp_file_init(void)
                         fclose(filep);
                         return 1;
                 }
-                while (!feof(filep)) {
+                for (;;) {
                         readp = &record[records_read];
                         records_read += fread(readp, sizeof(struct kvp_record),
                                         ENTRIES_PER_BLOCK,
                                         filep);
 
+                        if (ferror(filep)) {
+                                syslog(LOG_ERR, "Failed to read file, pool: %d",
+                                       i);
+                                exit(EXIT_FAILURE);
+                        }
+
                         if (!feof(filep)) {
                                 /*
                                  * We have more data to read.