Function intr_event_describe_handler

freebsd/kern/kern_intr.c:650–699

* Append a description preceded by a ':' to the name of the specified * interrupt handler. */

 * interrupt handler.
 */
int
intr_event_describe_handler(struct intr_event *ie, void *cookie,
    const char *descr)
{
	struct intr_handler *ih;
	size_t space;
	char *start;

	mtx_lock(&ie->ie_lock);
#ifdef INVARIANTS
	CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
		if (ih == cookie)
			break;
	}
	if (ih == NULL) {
		mtx_unlock(&ie->ie_lock);
		panic("handler %p not found in interrupt event %p", cookie, ie);
	}
#endif
	ih = cookie;

	/*
	 * Look for an existing description by checking for an
	 * existing ":".  This assumes device names do not include
	 * colons.  If one is found, prepare to insert the new
	 * description at that point.  If one is not found, find the
	 * end of the name to use as the insertion point.
	 */
	start = strchr(ih->ih_name, ':');
	if (start == NULL)
		start = strchr(ih->ih_name, 0);

	/*
	 * See if there is enough remaining room in the string for the
	 * description + ":".  The "- 1" leaves room for the trailing
	 * '\0'.  The "+ 1" accounts for the colon.
	 */
	space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
	if (strlen(descr) + 1 > space) {
		mtx_unlock(&ie->ie_lock);
		return (ENOSPC);
	}

	/* Append a colon followed by the description. */
	*start = ':';
	strcpy(start + 1, descr);
	intr_event_update(ie);
	mtx_unlock(&ie->ie_lock);
	return (0);
}

/*
 * Return the ie_source field from the intr_event an intr_handler is