Check that FILE_STREAM(channel) is not already closed

isc_log_closefilelogs can also close log files.  isc_log_doit failed
to check if the file handle was still valid before closing it.

diff --git a/lib/isc/log.c b/lib/isc/log.c
index 472c57d956a430370deb9fe30175acefd9534d52..53785df3c632bd85deac730720bfdfaff8856ebe 100644 (file)
--- a/lib/isc/log.c
+++ b/lib/isc/log.c
@@ -1762,8 +1762,11 @@ isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
                                     errno == ENOENT) ||
                                    statbuf.st_size < FILE_MAXSIZE(channel))
                                {
-                                       (void)fclose(FILE_STREAM(channel));
-                                       FILE_STREAM(channel) = NULL;
+                                       if (FILE_STREAM(channel) != NULL) {
+                                               (void)fclose(
+                                                       FILE_STREAM(channel));
+                                               FILE_STREAM(channel) = NULL;
+                                       }
                                        FILE_MAXREACHED(channel) = false;
                                } else {
                                        /*