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>

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 01b3ca5..3922abc 100644 (file)
--- 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.