1 files changed, 474 insertions, 0 deletions
diff --git a/src/libudev-queue.c b/src/libudev-queue.c
new file mode 100644
index 0000000000..3d46b67d19
--- /dev/null
+++ b/src/libudev-queue.c
@@ -0,0 +1,474 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2009 Alan Jenkins <alan-jenkins@tuffmail.co.uk>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/stat.h>
+
+#include "libudev.h"
+#include "libudev-private.h"
+
+/**
+ * SECTION:libudev-queue
+ * @short_description: access to currently active events
+ *
+ * The udev daemon processes events asynchronously. All events which do not have
+ * interdependencies run in parallel. This exports the current state of the
+ * event processing queue, and the current event sequence numbers from the kernel
+ * and the udev daemon.
+ */
+
+/**
+ * udev_queue:
+ *
+ * Opaque object representing the current event queue in the udev daemon.
+ */
+struct udev_queue {
+	struct udev *udev;
+	int refcount;
+	struct udev_list queue_list;
+};
+
+/**
+ * udev_queue_new:
+ * @udev: udev library context
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev queue context.
+ *
+ * Returns: the udev queue context, or #NULL on error.
+ **/
+UDEV_EXPORT struct udev_queue *udev_queue_new(struct udev *udev)
+{
+	struct udev_queue *udev_queue;
+
+	if (udev == NULL)
+		return NULL;
+
+	udev_queue = calloc(1, sizeof(struct udev_queue));
+	if (udev_queue == NULL)
+		return NULL;
+	udev_queue->refcount = 1;
+	udev_queue->udev = udev;
+	udev_list_init(udev, &udev_queue->queue_list, false);
+	return udev_queue;
+}
+
+/**
+ * udev_queue_ref:
+ * @udev_queue: udev queue context
+ *
+ * Take a reference of a udev queue context.
+ *
+ * Returns: the same udev queue context.
+ **/
+UDEV_EXPORT struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue)
+{
+	if (udev_queue == NULL)
+		return NULL;
+	udev_queue->refcount++;
+	return udev_queue;
+}
+
+/**
+ * udev_queue_unref:
+ * @udev_queue: udev queue context
+ *
+ * Drop a reference of a udev queue context. If the refcount reaches zero,
+ * the resources of the queue context will be released.
+ **/
+UDEV_EXPORT void udev_queue_unref(struct udev_queue *udev_queue)
+{
+	if (udev_queue == NULL)
+		return;
+	udev_queue->refcount--;
+	if (udev_queue->refcount > 0)
+		return;
+	udev_list_cleanup(&udev_queue->queue_list);
+	free(udev_queue);
+}
+
+/**
+ * udev_queue_get_udev:
+ * @udev_queue: udev queue context
+ *
+ * Retrieve the udev library context the queue context was created with.
+ *
+ * Returns: the udev library context.
+ **/
+UDEV_EXPORT struct udev *udev_queue_get_udev(struct udev_queue *udev_queue)
+{
+	if (udev_queue == NULL)
+		return NULL;
+	return udev_queue->udev;
+}
+
+unsigned long long int udev_get_kernel_seqnum(struct udev *udev)
+{
+	char filename[UTIL_PATH_SIZE];
+	unsigned long long int seqnum;
+	int fd;
+	char buf[32];
+	ssize_t len;
+
+	util_strscpyl(filename, sizeof(filename), udev_get_sys_path(udev), "/kernel/uevent_seqnum", NULL);
+	fd = open(filename, O_RDONLY|O_CLOEXEC);
+	if (fd < 0)
+		return 0;
+	len = read(fd, buf, sizeof(buf));
+	close(fd);
+	if (len <= 2)
+		return 0;
+	buf[len-1] = '\0';
+	seqnum = strtoull(buf, NULL, 10);
+	return seqnum;
+}
+
+/**
+ * udev_queue_get_kernel_seqnum:
+ * @udev_queue: udev queue context
+ *
+ * Returns: the current kernel event sequence number.
+ **/
+UDEV_EXPORT unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue)
+{
+	unsigned long long int seqnum;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+
+	seqnum = udev_get_kernel_seqnum(udev_queue->udev);
+	dbg(udev_queue->udev, "seqnum=%llu\n", seqnum);
+	return seqnum;
+}
+
+int udev_queue_read_seqnum(FILE *queue_file, unsigned long long int *seqnum)
+{
+	if (fread(seqnum, sizeof(unsigned long long int), 1, queue_file) != 1)
+		return -1;
+
+	return 0;
+}
+
+ssize_t udev_queue_skip_devpath(FILE *queue_file)
+{
+	unsigned short int len;
+
+	if (fread(&len, sizeof(unsigned short int), 1, queue_file) == 1) {
+		char devpath[len];
+
+		/* use fread to skip, fseek might drop buffered data */
+		if (fread(devpath, 1, len, queue_file) == len)
+			return len;
+	}
+
+	return -1;
+}
+
+ssize_t udev_queue_read_devpath(FILE *queue_file, char *devpath, size_t size)
+{
+	unsigned short int read_bytes = 0;
+	unsigned short int len;
+
+	if (fread(&len, sizeof(unsigned short int), 1, queue_file) != 1)
+		return -1;
+
+	read_bytes = (len < size - 1) ? len : size - 1;
+	if (fread(devpath, 1, read_bytes, queue_file) != read_bytes)
+		return -1;
+	devpath[read_bytes] = '\0';
+
+	/* if devpath was too long, skip unread characters */
+	if (read_bytes != len) {
+		unsigned short int skip_bytes = len - read_bytes;
+		char buf[skip_bytes];
+
+		if (fread(buf, 1, skip_bytes, queue_file) != skip_bytes)
+			return -1;
+	}
+
+	return read_bytes;
+}
+
+static FILE *open_queue_file(struct udev_queue *udev_queue, unsigned long long int *seqnum_start)
+{
+	char filename[UTIL_PATH_SIZE];
+	FILE *queue_file;
+
+	util_strscpyl(filename, sizeof(filename), udev_get_run_path(udev_queue->udev), "/queue.bin", NULL);
+	queue_file = fopen(filename, "re");
+	if (queue_file == NULL)
+		return NULL;
+
+	if (udev_queue_read_seqnum(queue_file, seqnum_start) < 0) {
+		err(udev_queue->udev, "corrupt queue file\n");
+		fclose(queue_file);
+		return NULL;
+	}
+
+	return queue_file;
+}
+
+/**
+ * udev_queue_get_udev_seqnum:
+ * @udev_queue: udev queue context
+ *
+ * Returns: the last known udev event sequence number.
+ **/
+UDEV_EXPORT unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue)
+{
+	unsigned long long int seqnum_udev;
+	FILE *queue_file;
+
+	queue_file = open_queue_file(udev_queue, &seqnum_udev);
+	if (queue_file == NULL)
+		return 0;
+
+	for (;;) {
+		unsigned long long int seqnum;
+		ssize_t devpath_len;
+
+		if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
+			break;
+		devpath_len = udev_queue_skip_devpath(queue_file);
+		if (devpath_len < 0)
+			break;
+		if (devpath_len > 0)
+			seqnum_udev = seqnum;
+	}
+
+	fclose(queue_file);
+	return seqnum_udev;
+}
+
+/**
+ * udev_queue_get_udev_is_active:
+ * @udev_queue: udev queue context
+ *
+ * Returns: a flag indicating if udev is active.
+ **/
+UDEV_EXPORT int udev_queue_get_udev_is_active(struct udev_queue *udev_queue)
+{
+	unsigned long long int seqnum_start;
+	FILE *queue_file;
+
+	queue_file = open_queue_file(udev_queue, &seqnum_start);
+	if (queue_file == NULL)
+		return 0;
+
+	fclose(queue_file);
+	return 1;
+}
+
+/**
+ * udev_queue_get_queue_is_empty:
+ * @udev_queue: udev queue context
+ *
+ * Returns: a flag indicating if udev is currently handling events.
+ **/
+UDEV_EXPORT int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue)
+{
+	unsigned long long int seqnum_kernel;
+	unsigned long long int seqnum_udev = 0;
+	int queued = 0;
+	int is_empty = 0;
+	FILE *queue_file;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	queue_file = open_queue_file(udev_queue, &seqnum_udev);
+	if (queue_file == NULL)
+		return 1;
+
+	for (;;) {
+		unsigned long long int seqnum;
+		ssize_t devpath_len;
+
+		if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
+			break;
+		devpath_len = udev_queue_skip_devpath(queue_file);
+		if (devpath_len < 0)
+			break;
+
+		if (devpath_len > 0) {
+			queued++;
+			seqnum_udev = seqnum;
+		} else {
+			queued--;
+		}
+	}
+
+	if (queued > 0) {
+		dbg(udev_queue->udev, "queue is not empty\n");
+		goto out;
+	}
+
+	seqnum_kernel = udev_queue_get_kernel_seqnum(udev_queue);
+	if (seqnum_udev < seqnum_kernel) {
+		dbg(udev_queue->udev, "queue is empty but kernel events still pending [%llu]<->[%llu]\n",
+					seqnum_kernel, seqnum_udev);
+		goto out;
+	}
+
+	dbg(udev_queue->udev, "queue is empty\n");
+	is_empty = 1;
+
+out:
+	fclose(queue_file);
+	return is_empty;
+}
+
+/**
+ * udev_queue_get_seqnum_sequence_is_finished:
+ * @udev_queue: udev queue context
+ * @start: first event sequence number
+ * @end: last event sequence number
+ *
+ * Returns: a flag indicating if any of the sequence numbers in the given range is currently active.
+ **/
+UDEV_EXPORT int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_queue,
+					       unsigned long long int start, unsigned long long int end)
+{
+	unsigned long long int seqnum;
+	ssize_t devpath_len;
+	int unfinished;
+	FILE *queue_file;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	queue_file = open_queue_file(udev_queue, &seqnum);
+	if (queue_file == NULL)
+		return 1;
+	if (start < seqnum)
+		start = seqnum;
+	if (start > end) {
+		fclose(queue_file);
+		return 1;
+	}
+	if (end - start > INT_MAX - 1) {
+		fclose(queue_file);
+		return -EOVERFLOW;
+	}
+
+	/*
+	 * we might start with 0, and handle the initial seqnum
+	 * only when we find an entry in the queue file
+	 **/
+	unfinished = end - start;
+
+	do {
+		if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
+			break;
+		devpath_len = udev_queue_skip_devpath(queue_file);
+		if (devpath_len < 0)
+			break;
+
+		/*
+		 * we might start with an empty or re-build queue file, where
+		 * the initial seqnum is not recorded as finished
+		 */
+		if (start == seqnum && devpath_len > 0)
+			unfinished++;
+
+		if (devpath_len == 0) {
+			if (seqnum >= start && seqnum <= end)
+				unfinished--;
+		}
+	} while (unfinished > 0);
+
+	fclose(queue_file);
+
+	return (unfinished == 0);
+}
+
+/**
+ * udev_queue_get_seqnum_is_finished:
+ * @udev_queue: udev queue context
+ * @seqnum: sequence number
+ *
+ * Returns: a flag indicating if the given sequence number is currently active.
+ **/
+UDEV_EXPORT int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum)
+{
+	if (!udev_queue_get_seqnum_sequence_is_finished(udev_queue, seqnum, seqnum))
+		return 0;
+
+	dbg(udev_queue->udev, "seqnum: %llu finished\n", seqnum);
+	return 1;
+}
+
+/**
+ * udev_queue_get_queued_list_entry:
+ * @udev_queue: udev queue context
+ *
+ * Returns: the first entry of the list of queued events.
+ **/
+UDEV_EXPORT struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue)
+{
+	unsigned long long int seqnum;
+	FILE *queue_file;
+
+	if (udev_queue == NULL)
+		return NULL;
+	udev_list_cleanup(&udev_queue->queue_list);
+
+	queue_file = open_queue_file(udev_queue, &seqnum);
+	if (queue_file == NULL)
+		return NULL;
+
+	for (;;) {
+		char syspath[UTIL_PATH_SIZE];
+		char *s;
+		size_t l;
+		ssize_t len;
+		char seqnum_str[32];
+		struct udev_list_entry *list_entry;
+
+		if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
+			break;
+		snprintf(seqnum_str, sizeof(seqnum_str), "%llu", seqnum);
+
+		s = syspath;
+		l = util_strpcpyl(&s, sizeof(syspath), udev_get_sys_path(udev_queue->udev), NULL);
+		len = udev_queue_read_devpath(queue_file, s, l);
+		if (len < 0)
+			break;
+
+		if (len > 0) {
+			udev_list_entry_add(&udev_queue->queue_list, syspath, seqnum_str);
+		} else {
+			udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_queue->queue_list)) {
+				if (strcmp(seqnum_str, udev_list_entry_get_value(list_entry)) == 0) {
+					udev_list_entry_delete(list_entry);
+					break;
+				}
+			}
+		}
+	}
+	fclose(queue_file);
+
+	return udev_list_get_entry(&udev_queue->queue_list);
+}
+
+struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue);
+UDEV_EXPORT struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue)
+{
+	errno = ENOSYS;
+	return NULL;
+}