libudev: add queue interface

udev/lib/Makefile.am

@@ -24,7 +24,8 @@ libudev_la_SOURCES =\
 	libudev-device.c \
 	libudev-enumerate.c \
 	libudev-ctrl.c \
-	libudev-monitor.c
+	libudev-monitor.c \
+	libudev-queue.c
 
 libudev_la_LDFLAGS = \
 	-version-info $(LIBUDEV_LT_CURRENT):$(LIBUDEV_LT_REVISION):$(LIBUDEV_LT_AGE) \

udev/lib/exported_symbols

@@ -51,3 +51,13 @@ udev_monitor_unref
 udev_monitor_get_udev
 udev_monitor_get_fd
 udev_monitor_receive_device
+udev_queue_new
+udev_queue_ref
+udev_queue_unref
+udev_queue_get_udev
+udev_queue_get_kernel_seqnum
+udev_queue_get_udev_seqnum
+udev_queue_get_queue_is_empty
+udev_queue_get_seqnum_is_finished
+udev_queue_get_queued_list_entry
+udev_queue_get_failed_list_entry

udev/lib/libudev-private.h

@@ -120,6 +120,12 @@ extern void list_entry_move_to_end(struct udev_list_entry *list_entry);
 	     entry != NULL; \
 	     entry = tmp, tmp = udev_list_entry_get_next(tmp))
 
+/* libudev-queue */
+extern int queue_export_udev_seqnum(struct udev_queue *udev_queue, unsigned long long int seqnum);
+extern int queue_export_device_queued(struct udev_queue *udev_queue, struct udev_device *udev_device);
+extern int queue_export_device_finished(struct udev_queue *udev_queue, struct udev_device *udev_device);
+extern int queue_export_device_failed(struct udev_queue *udev_queue, struct udev_device *udev_device);
+
 /* libudev-utils */
 #define UTIL_PATH_SIZE		1024
 #define UTIL_LINE_SIZE		2048

udev/lib/libudev-queue.c

@@ -0,0 +1,286 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#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 <sys/stat.h>
+
+#include "libudev.h"
+#include "libudev-private.h"
+
+struct udev_queue {
+	struct udev *udev;
+	int refcount;
+	unsigned long long int last_seen_udev_seqnum;
+	struct list_node queue_list;
+	struct list_node failed_list;
+};
+
+struct udev_queue *udev_queue_new(struct udev *udev)
+{
+	struct udev_queue *udev_queue;
+
+	if (udev == NULL)
+		return NULL;
+
+	udev_queue = malloc(sizeof(struct udev_queue));
+	if (udev_queue == NULL)
+		return NULL;
+	memset(udev_queue, 0x00, sizeof(struct udev_queue));
+	udev_queue->refcount = 1;
+	udev_queue->udev = udev;
+	list_init(&udev_queue->queue_list);
+	list_init(&udev_queue->failed_list);
+	return udev_queue;
+}
+
+struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue)
+{
+	if (udev_queue == NULL)
+		return NULL;
+	udev_queue->refcount++;
+	return udev_queue;
+}
+
+void udev_queue_unref(struct udev_queue *udev_queue)
+{
+	if (udev_queue == NULL)
+		return;
+	udev_queue->refcount--;
+	if (udev_queue->refcount > 0)
+		return;
+	list_cleanup(udev_queue->udev, &udev_queue->queue_list);
+	list_cleanup(udev_queue->udev, &udev_queue->failed_list);
+	free(udev_queue);
+}
+
+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_queue_get_kernel_seqnum(struct udev_queue *udev_queue)
+{
+	char filename[UTIL_PATH_SIZE];
+	unsigned long long int seqnum;
+	int fd;
+	char buf[32];
+	ssize_t len;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	util_strlcpy(filename, udev_get_sys_path(udev_queue->udev), sizeof(filename));
+	util_strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
+	fd = open(filename, O_RDONLY);
+	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);
+	info(udev_queue->udev, "seqnum=%llu\n", seqnum);
+	return seqnum;
+}
+
+unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue)
+{
+	char filename[UTIL_PATH_SIZE];
+	unsigned long long int seqnum;
+	int fd;
+	char buf[32];
+	ssize_t len;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	util_strlcpy(filename, udev_get_dev_path(udev_queue->udev), sizeof(filename));
+	util_strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
+	fd = open(filename, O_RDONLY);
+	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);
+	info(udev_queue->udev, "seqnum=%llu\n", seqnum);
+	udev_queue->last_seen_udev_seqnum = seqnum;
+	return seqnum;
+}
+
+int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue)
+{
+	char queuename[UTIL_PATH_SIZE];
+	struct stat statbuf;
+	unsigned long long int seqnum_kernel;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	util_strlcpy(queuename, udev_get_dev_path(udev_queue->udev), sizeof(queuename));
+	util_strlcat(queuename, "/.udev/queue", sizeof(queuename));
+	if (stat(queuename, &statbuf) == 0) {
+		info(udev_queue->udev, "queue is not empty\n");
+		return 0;
+	}
+	seqnum_kernel = udev_queue_get_kernel_seqnum(udev_queue);
+	if (seqnum_kernel <= udev_queue->last_seen_udev_seqnum) {
+		info(udev_queue->udev, "queue is empty\n");
+		return 1;
+	}
+	udev_queue_get_udev_seqnum(udev_queue);
+	if (seqnum_kernel <= udev_queue->last_seen_udev_seqnum) {
+		info(udev_queue->udev, "queue is empty\n");
+		return 1;
+	}
+	info(udev_queue->udev, "queue is empty, but kernel events still pending [%llu]<->[%llu]\n",
+	     seqnum_kernel, udev_queue->last_seen_udev_seqnum);
+	return 0;
+}
+
+int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum)
+{
+	char filename[UTIL_PATH_SIZE];
+	struct stat statbuf;
+
+	if (udev_queue == NULL)
+		return -EINVAL;
+	/* if we have not seen this seqnum, check if it is/was already queued */
+	if (seqnum < udev_queue->last_seen_udev_seqnum) {
+		udev_queue_get_udev_seqnum(udev_queue);
+		if (seqnum < udev_queue->last_seen_udev_seqnum)
+			return 0;
+	}
+	snprintf(filename, sizeof(filename), "%s/.udev/queue/%llu",
+		 udev_get_dev_path(udev_queue->udev), seqnum);
+	if (stat(filename, &statbuf) == 0)
+		return 0;
+	info(udev_queue->udev, "seqnum: %llu finished\n", seqnum);
+	return 1;
+}
+
+struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue)
+{
+	char path[UTIL_PATH_SIZE];
+	DIR *dir;
+	struct dirent *dent;
+
+	if (udev_queue == NULL)
+		return NULL;
+	list_cleanup(udev_queue->udev, &udev_queue->queue_list);
+	util_strlcpy(path, udev_get_dev_path(udev_queue->udev), sizeof(path));
+	util_strlcat(path, "/.udev/queue", sizeof(path));
+	dir = opendir(path);
+	if (dir == NULL)
+		return NULL;
+	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+		char filename[UTIL_PATH_SIZE];
+		char syspath[UTIL_PATH_SIZE];
+		size_t syslen;
+		ssize_t len;
+
+		if (dent->d_name[0] == '.')
+			continue;
+		util_strlcpy(filename, path, sizeof(filename));
+		util_strlcat(filename, "/", sizeof(filename));
+		util_strlcat(filename, dent->d_name, sizeof(filename));
+
+		syslen = util_strlcpy(syspath, udev_get_sys_path(udev_queue->udev), sizeof(syspath));
+		len = readlink(filename, &syspath[syslen], sizeof(syspath)-syslen);
+		if (len < 0 || len >= (ssize_t)(sizeof(syspath)-syslen))
+			continue;
+		syspath[syslen + len] = '\0';
+		info(udev_queue->udev, "found '%s' [%s]\n", syspath, dent->d_name);
+		list_entry_add(udev_queue->udev, &udev_queue->queue_list, syspath, dent->d_name, 0, 0);
+	}
+	closedir(dir);
+	return list_get_entry(&udev_queue->queue_list);
+}
+
+struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue)
+{
+	char path[UTIL_PATH_SIZE];
+	DIR *dir;
+	struct dirent *dent;
+
+	if (udev_queue == NULL)
+		return NULL;
+	list_cleanup(udev_queue->udev, &udev_queue->failed_list);
+	util_strlcpy(path, udev_get_dev_path(udev_queue->udev), sizeof(path));
+	util_strlcat(path, "/.udev/failed", sizeof(path));
+	dir = opendir(path);
+	if (dir == NULL)
+		return NULL;
+	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+		char filename[UTIL_PATH_SIZE];
+		char syspath[UTIL_PATH_SIZE];
+		struct stat statbuf;
+		size_t syslen;
+		ssize_t len;
+
+		if (dent->d_name[0] == '.')
+			continue;
+		util_strlcpy(filename, path, sizeof(filename));
+		util_strlcat(filename, "/", sizeof(filename));
+		util_strlcat(filename, dent->d_name, sizeof(filename));
+
+		syslen = util_strlcpy(syspath, udev_get_sys_path(udev_queue->udev), sizeof(syspath));
+		len = readlink(filename, &syspath[syslen], sizeof(syspath)-syslen);
+		if (len < 0 || len >= (ssize_t)(sizeof(syspath)-syslen))
+			continue;
+		syspath[syslen + len] = '\0';
+		info(udev_queue->udev, "found '%s' [%s]\n", syspath, dent->d_name);
+		util_strlcpy(filename, syspath, sizeof(filename));
+		util_strlcat(filename, "/uevent", sizeof(filename));
+		if (stat(filename, &statbuf) != 0)
+			continue;
+		list_entry_add(udev_queue->udev, &udev_queue->failed_list, syspath, NULL, 0, 0);
+	}
+	closedir(dir);
+	return list_get_entry(&udev_queue->failed_list);
+}
+
+int queue_export_udev_seqnum(struct udev_queue *udev_queue, unsigned long long int seqnum)
+{
+	return 0;
+}
+
+extern int queue_export_device_queued(struct udev_queue *udev_queue, struct udev_device *udev_device)
+{
+	return 0;
+}
+
+extern int queue_export_device_finished(struct udev_queue *udev_queue, struct udev_device *udev_device)
+{
+	return 0;
+}
+
+extern int queue_export_device_failed(struct udev_queue *udev_queue, struct udev_device *udev_device)
+{
+	return 0;
+}

udev/lib/libudev.h

@@ -96,8 +96,8 @@ extern struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev
 struct udev_enumerate;
 extern struct udev_enumerate *udev_enumerate_new(struct udev *udev);
 extern struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate);
-extern struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate);
 extern void udev_enumerate_unref(struct udev_enumerate *udev_enumerate);
+extern struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate);
 extern int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem);
 extern int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem);
 extern int udev_enumerate_add_match_attr(struct udev_enumerate *udev_enumerate, const char *attr, const char *value);
@@ -107,4 +107,16 @@ extern int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate);
 extern int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate);
 extern struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate);
 
+/* event queue */
+struct udev_queue;
+extern struct udev_queue *udev_queue_new(struct udev *udev);
+extern struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue);
+extern void udev_queue_unref(struct udev_queue *udev_queue);
+extern struct udev *udev_queue_get_udev(struct udev_queue *udev_queue);
+extern unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue);
+extern unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue);
+extern int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue);
+extern int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum);
+extern struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue);
+extern struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue);
 #endif

udev/lib/test-libudev.c

@@ -19,6 +19,7 @@
 
 #include <stdio.h>
 #include <stdarg.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
@@ -168,10 +169,9 @@ static int test_enumerate_print_list(struct udev_enumerate *enumerate)
 		device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
 						      udev_list_entry_get_name(list_entry));
 		if (device != NULL) {
-			printf("device:    '%s' (%s) '%s'\n",
+			printf("device: '%s' (%s)\n",
 			       udev_device_get_syspath(device),
-			       udev_device_get_subsystem(device),
-			       udev_device_get_sysname(device));
+			       udev_device_get_subsystem(device));
 			udev_device_unref(device);
 			count++;
 		}
@@ -230,6 +230,49 @@ static int test_monitor(struct udev *udev, const char *socket_path)
 	return 0;
 }
 
+static int test_queue(struct udev *udev)
+{
+	struct udev_queue *udev_queue;
+	unsigned long long int seqnum;
+	struct udev_list_entry *list_entry;
+
+	udev_queue = udev_queue_new(udev);
+	if (udev_queue == NULL)
+		return -1;
+	seqnum = udev_queue_get_kernel_seqnum(udev_queue);
+	printf("seqnum kernel: %llu\n", seqnum);
+	seqnum = udev_queue_get_udev_seqnum(udev_queue);
+	printf("seqnum udev  : %llu\n", seqnum);
+
+	if (udev_queue_get_queue_is_empty(udev_queue))
+		printf("queue is empty\n");
+	printf("get queue list\n");
+	udev_list_entry_foreach(list_entry, udev_queue_get_queued_list_entry(udev_queue))
+		printf("queued: '%s' [%s]\n", udev_list_entry_get_name(list_entry), udev_list_entry_get_value(list_entry));
+	printf("\n");
+	printf("get queue list again\n");
+	udev_list_entry_foreach(list_entry, udev_queue_get_queued_list_entry(udev_queue))
+		printf("queued: '%s' [%s]\n", udev_list_entry_get_name(list_entry), udev_list_entry_get_value(list_entry));
+	printf("\n");
+	printf("get failed list\n");
+	udev_list_entry_foreach(list_entry, udev_queue_get_failed_list_entry(udev_queue))
+		printf("failed: '%s'\n", udev_list_entry_get_name(list_entry));
+	printf("\n");
+
+	list_entry = udev_queue_get_queued_list_entry(udev_queue);
+	if (list_entry != NULL) {
+		printf("event [%llu] is queued\n", seqnum);
+		seqnum = strtoull(udev_list_entry_get_value(list_entry), NULL, 10);
+		if (udev_queue_get_seqnum_is_finished(udev_queue, seqnum))
+			printf("event [%llu] is not finished\n", seqnum);
+		else
+			printf("event [%llu] is finished\n", seqnum);
+	}
+	printf("\n");
+	udev_queue_unref(udev_queue);
+	return 0;
+}
+
 int main(int argc, char *argv[], char *envp[])
 {
 	struct udev *udev = NULL;
@@ -351,6 +394,8 @@ int main(int argc, char *argv[], char *envp[])
 	test_enumerate_print_list(udev_enumerate);
 	udev_enumerate_unref(udev_enumerate);
 
+	test_queue(udev);
+
 	test_monitor(udev, socket);
 out:
 	udev_unref(udev);