udevd: export current seqnum and add udevsettle

1 files changed, 155 insertions, 0 deletions

diff --git a/udevsettle.c b/udevsettle.c
new file mode 100644
index 0000000000..f0f85ff059
--- /dev/null
+++ b/udevsettle.c
@@ -0,0 +1,155 @@
+/*
+ * udevsettle.c
+ *
+ * Copyright (C) 2006 Kay Sievers <kay@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 version 2 of the License.
+ * 
+ *	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, write to the Free Software Foundation, Inc.,
+ *	675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "udev.h"
+#include "udevd.h"
+
+#define LOOP_PER_SECOND			20
+
+static const char *udev_log_str;
+
+#ifdef USE_LOG
+void log_message(int priority, const char *format, ...)
+{
+	va_list args;
+
+	if (priority > udev_log_priority)
+		return;
+
+	va_start(args, format);
+	vsyslog(priority, format, args);
+	va_end(args);
+}
+#endif
+
+int main(int argc, char *argv[], char *envp[])
+{
+	char queuename[PATH_SIZE];
+	char filename[PATH_SIZE];
+	unsigned long long seq_kernel;
+	unsigned long long seq_udev;
+	char seqnum[32];
+	int fd;
+	ssize_t len;
+	int timeout = 30;
+	int loop;
+	int i;
+	int rc = 1;
+
+	logging_init("udevsettle");
+	udev_config_init();
+	dbg("version %s", UDEV_VERSION);
+
+	udev_log_str = getenv("UDEV_LOG");
+
+	for (i = 1 ; i < argc; i++) {
+		char *arg = argv[i];
+
+		if (strncmp(arg, "--timeout=", 10) == 0) {
+			char *str = &arg[10];
+
+			timeout = atoi(str);
+			dbg("timeout=%i", timeout);
+			if (timeout <= 0) {
+				fprintf(stderr, "Invalid timeout value.\n");
+				goto exit;
+			}
+		} else {
+			fprintf(stderr, "Usage: udevsettle [--timeout=<seconds>]\n");
+			goto exit;
+		}
+	}
+
+	sysfs_init();
+	strlcpy(queuename, udev_root, sizeof(queuename));
+	strlcat(queuename, "/" EVENT_QUEUE_DIR, sizeof(queuename));
+
+	loop = timeout * LOOP_PER_SECOND;
+	while (loop--) {
+		/* wait for events in queue to finish */
+		while (loop--) {
+			struct stat statbuf;
+
+			if (stat(queuename, &statbuf) < 0) {
+				info("queue is empty");
+				break;
+			}
+			usleep(1000 * 1000 / LOOP_PER_SECOND);
+		}
+		if (loop <= 0) {
+			info("timeout waiting for queue");
+			goto exit;
+		}
+
+		/* read current kernel seqnum */
+		strlcpy(filename, sysfs_path, sizeof(filename));
+		strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
+		fd = open(filename, O_RDONLY);
+		if (fd < 0)
+			goto exit;
+		len = read(fd, seqnum, sizeof(seqnum)-1);
+		close(fd);
+		if (len <= 0)
+			goto exit;
+		seqnum[len] = '\0';
+		seq_kernel = strtoull(seqnum, NULL, 10);
+		info("kernel seqnum = %llu", seq_kernel);
+
+		/* read current udev seqnum */
+		strlcpy(filename, udev_root, sizeof(filename));
+		strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
+		fd = open(filename, O_RDONLY);
+		if (fd < 0)
+			goto exit;
+		len = read(fd, seqnum, sizeof(seqnum)-1);
+		close(fd);
+		if (len <= 0)
+			goto exit;
+		seqnum[len] = '\0';
+		seq_udev = strtoull(seqnum, NULL, 10);
+		info("udev seqnum = %llu", seq_udev);
+
+		/* make sure all kernel events have arrived in the queue */
+		if (seq_udev >= seq_kernel) {
+			info("queue is empty and no pending events left");
+			rc = 0;
+			goto exit;
+		}
+		usleep(1000 * 1000 / LOOP_PER_SECOND);
+		info("queue is empty, but events still pending");
+	}
+
+exit:
+	sysfs_cleanup();
+	logging_close();
+	return rc;
+}