disk plugin: Support Linux kernels with additional fields.

Linux 4.19 will add additional counters, which caused this plugin to
bail out because it checked the number of fields exactly instead of
ensuring that there are *at least* the number of fields expected.

Fixes: #2951

diff --git a/src/disk.c b/src/disk.c
index e01e150..cfda635 100644 (file)
--- a/src/disk.c
+++ b/src/disk.c
@@ -695,7 +695,9 @@ static int disk_read(void) {
 
     numfields = strsplit(buffer, fields, 32);
 
-    if ((numfields != (14 + fieldshift)) && (numfields != 7))
+    /* need either 7 fields (partition)
+     * or at least 14 fields (15 on Linux 2.4) */
+    if ((numfields != 7) && (numfields < (14 + fieldshift)))
       continue;
 
     minor = atoll(fields[1]);
@@ -729,7 +731,8 @@ static int disk_read(void) {
       read_sectors = atoll(fields[4]);
       write_ops = atoll(fields[5]);
       write_sectors = atoll(fields[6]);
-    } else if (numfields == (14 + fieldshift)) {
+    } else {
+      assert(numfields >= (14 + fieldshift));
       read_ops = atoll(fields[3 + fieldshift]);
       write_ops = atoll(fields[7 + fieldshift]);
 
@@ -748,9 +751,6 @@ static int disk_read(void) {
         io_time = atof(fields[12 + fieldshift]);
         weighted_time = atof(fields[13 + fieldshift]);
       }
-    } else {
-      DEBUG("numfields = %i; => unknown file format.", numfields);
-      continue;
     }
 
     {