lxcContainerSetReadOnly: Refactor cleanup handling

Turn 'mounts' into a proper GStrv after sorting so that automatic
cleanup can be used and shuffle around the cleanup steps so that jumps
can be avoided in favor of direct return of error code.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/lxc/lxc_container.c

@@ -773,8 +773,7 @@ static int lxcContainerSetReadOnly(void)
     FILE *procmnt;
     struct mntent mntent;
     char mntbuf[1024];
-    int ret = -1;
-    char **mounts = NULL;
+    g_auto(GStrv) mounts = NULL;
     size_t nmounts = 0;
     size_t i;
 
@@ -797,13 +796,16 @@ static int lxcContainerSetReadOnly(void)
         VIR_APPEND_ELEMENT(mounts, nmounts, tmp);
     }
 
-    if (!mounts) {
-        ret = 0;
-        goto cleanup;
-    }
+    endmntent(procmnt);
 
-    qsort(mounts, nmounts, sizeof(mounts[0]),
-          virStringSortRevCompare);
+    if (!mounts)
+        return 0;
+
+    qsort(mounts, nmounts, sizeof(mounts[0]), virStringSortRevCompare);
+
+    /* turn 'mounts' into a proper GStrv */
+    VIR_EXPAND_N(mounts, nmounts, 1);
+    nmounts--;
 
     for (i = 0; i < nmounts; i++) {
         VIR_DEBUG("Bind readonly %s", mounts[i]);
@@ -811,16 +813,11 @@ static int lxcContainerSetReadOnly(void)
             virReportSystemError(errno,
                                  _("Failed to make mount %s readonly"),
                                  mounts[i]);
-            goto cleanup;
+            return -1;
         }
     }
 
-    ret = 0;
- cleanup:
-    virStringListFreeCount(mounts, nmounts);
-    endmntent(procmnt);
-    return ret;
-
+    return 0;
 }