{
/* Parse configuration while holding the lock. This avoids
duplicate work. */
- conf = __resolv_conf_load (NULL, NULL);
+ struct file_change_detection after_load;
+ conf = __resolv_conf_load (NULL, &after_load);
if (conf != NULL)
{
if (global_copy->conf_current != NULL)
conf_decrement (global_copy->conf_current);
global_copy->conf_current = conf; /* Takes ownership. */
- /* Update file modification stamps. The configuration we
- read could be a newer version of the file, but this does
- not matter because this will lead to an extraneous reload
- later. */
- global_copy->file_resolve_conf = initial;
+ /* Update file change detection data, but only if it matches
+ the initial measurement. This avoids an ABA race in case
+ /etc/resolv.conf is temporarily replaced while the file
+ is read (after the initial measurement), and restored to
+ the initial version later. */
+ if (file_is_unchanged (&initial, &after_load))
+ global_copy->file_resolve_conf = after_load;
+ else
+ /* If there is a discrepancy, trigger a reload during the
+ next use. */
+ global_copy->file_resolve_conf.size = -1;
}
}