[PATCH v1 1/3] tools/usbip: support use case reconnect: prepare

Lars Gunnarsson
2021-10-06T20:48:23Z

This patch implements an usb monitor into libusbip to await usb events,
example connect and disconnect.

Signed-off-by: Lars Gunnarsson <gunnarsson.lars@gmail.com>
---
tools/usb/usbip/.gitignore | 1 +
tools/usb/usbip/libsrc/Makefile.am | 3 +-
tools/usb/usbip/libsrc/usbip_common.h | 1 +
tools/usb/usbip/libsrc/usbip_monitor.c | 147 +++++++++++++++++++++++++
tools/usb/usbip/libsrc/usbip_monitor.h | 21 ++++
5 files changed, 172 insertions(+), 1 deletion(-)
create mode 100644 tools/usb/usbip/libsrc/usbip_monitor.c
create mode 100644 tools/usb/usbip/libsrc/usbip_monitor.h

diff --git a/tools/usb/usbip/.gitignore b/tools/usb/usbip/.gitignore
index 597361a96dbb..6304adefb5e1 100644
--- a/tools/usb/usbip/.gitignore
+++ b/tools/usb/usbip/.gitignore
@@ -28,6 +28,7 @@ libsrc/libusbip_la-usbip_common.lo
libsrc/libusbip_la-usbip_device_driver.lo
libsrc/libusbip_la-usbip_host_common.lo
libsrc/libusbip_la-usbip_host_driver.lo
+libsrc/libusbip_la-usbip_monitor.lo
libsrc/libusbip_la-vhci_driver.lo
src/usbip
src/usbipd
diff --git a/tools/usb/usbip/libsrc/Makefile.am b/tools/usb/usbip/libsrc/Makefile.am
index dabd2c91d311..3e31e33729cf 100644
--- a/tools/usb/usbip/libsrc/Makefile.am
+++ b/tools/usb/usbip/libsrc/Makefile.am
@@ -8,4 +8,5 @@ libusbip_la_SOURCES := names.c names.h usbip_host_driver.c usbip_host_driver.h \
usbip_device_driver.c usbip_device_driver.h \
usbip_common.c usbip_common.h usbip_host_common.h \
usbip_host_common.c vhci_driver.c vhci_driver.h \
- sysfs_utils.c sysfs_utils.h
+ sysfs_utils.c sysfs_utils.h \
+ usbip_monitor.c
diff --git a/tools/usb/usbip/libsrc/usbip_common.h b/tools/usb/usbip/libsrc/usbip_common.h
index 73a367a7fa10..13f1d4ca47c5 100644
--- a/tools/usb/usbip/libsrc/usbip_common.h
+++ b/tools/usb/usbip/libsrc/usbip_common.h
@@ -30,6 +30,7 @@

/* kernel module names */
#define USBIP_CORE_MOD_NAME "usbip-core"
+#define USBIP_USB_DRV_NAME "usb"
#define USBIP_HOST_DRV_NAME "usbip-host"
#define USBIP_DEVICE_DRV_NAME "usbip-vudc"
#define USBIP_VHCI_DRV_NAME "vhci_hcd"
diff --git a/tools/usb/usbip/libsrc/usbip_monitor.c b/tools/usb/usbip/libsrc/usbip_monitor.c
new file mode 100644
index 000000000000..731d344f2965
--- /dev/null
+++ b/tools/usb/usbip/libsrc/usbip_monitor.c
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/**
+ * Copyright (C) 2021 Lars Gunnarsson
+ */
+#include <libudev.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/poll.h>
+
+#include "usbip_monitor.h"
+
+static const size_t MAX_STRLEN = 32;
+
+struct usbip_monitor {
+ const char *busid;
+ struct udev *udev;
+ struct udev_monitor *udev_monitor;
+};
+
+usbip_monitor_t *usbip_monitor_new(void)
+{
+ usbip_monitor_t *monitor = NULL;
+ struct udev *udev = udev_new();
+
+ if (udev) {
+ struct udev_monitor *udev_monitor =
+ udev_monitor_new_from_netlink(udev, "udev");
+ udev_monitor_filter_add_match_subsystem_devtype(
+ udev_monitor,
+ /*subsystem=*/"usb",
+ /*devtype=*/"usb_device");
+ udev_monitor_enable_receiving(udev_monitor);
+ monitor = malloc(sizeof(struct usbip_monitor));
+ monitor->busid = NULL;
+ monitor->udev = udev;
+ monitor->udev_monitor = udev_monitor;
+ }
+ return monitor;
+}
+
+void usbip_monitor_delete(usbip_monitor_t *monitor)
+{
+ if (monitor) {
+ udev_monitor_unref(monitor->udev_monitor);
+ udev_unref(monitor->udev);
+ free(monitor);
+ }
+}
+
+void usbip_monitor_set_busid(usbip_monitor_t *monitor, const char *busid)
+{
+ monitor->busid = busid;
+}
+
+static struct udev_device *await_udev_event(const usbip_monitor_t *monitor)
+{
+ struct udev_device *dev = NULL;
+ int fd = udev_monitor_get_fd(monitor->udev_monitor);
+ const int timeout = -1;
+ const int nfds = 1; // number of file descriptors
+ struct pollfd pollfd[] = { { fd, POLLIN, 0 } };
+ int nfd = poll(pollfd, nfds, timeout);
+
+ if (nfd) {
+ dev = udev_monitor_receive_device(monitor->udev_monitor);
+ }
+ return dev;
+}
+
+static int optional_filter_busid(const char *busid, const char *udev_busid)
+{
+ int filter_match = 0;
+
+ if (busid) {
+ if (strncmp(busid, udev_busid, MAX_STRLEN) == 0) {
+ filter_match = 1;
+ }
+ } else {
+ filter_match = 1;
+ }
+ return filter_match;
+}
+
+static void await_usb_with_driver(const usbip_monitor_t *monitor,
+ const char *driver, const char *action)
+{
+ while (1) {
+ struct udev_device *dev = await_udev_event(monitor);
+
+ if (dev) {
+ const char *udev_action = udev_device_get_action(dev);
+ const char *udev_driver = udev_device_get_driver(dev);
+ const char *udev_busid = udev_device_get_sysname(dev);
+
+ if (strncmp(udev_action, action, MAX_STRLEN) == 0 &&
+ strncmp(udev_driver, driver, MAX_STRLEN) == 0) {
+ if (optional_filter_busid(monitor->busid,
+ udev_busid)) {
+ break;
+ }
+ }
+ udev_device_unref(dev);
+ }
+ }
+}
+
+void usbip_monitor_await_usb_add(const usbip_monitor_t *monitor,
+ const char *driver)
+{
+ await_usb_with_driver(monitor, driver, "add");
+}
+
+void usbip_monitor_await_usb_bind(const usbip_monitor_t *monitor,
+ const char *driver)
+{
+ await_usb_with_driver(monitor, driver, "bind");
+}
+
+static void await_usb(const usbip_monitor_t *monitor, const char *action)
+{
+ while (1) {
+ struct udev_device *dev = await_udev_event(monitor);
+
+ if (dev) {
+ const char *udev_action = udev_device_get_action(dev);
+ const char *udev_busid = udev_device_get_sysname(dev);
+
+ if (strncmp(udev_action, action, MAX_STRLEN) == 0) {
+ if (optional_filter_busid(monitor->busid,
+ udev_busid)) {
+ break;
+ }
+ }
+ udev_device_unref(dev);
+ }
+ }
+}
+
+void usbip_monitor_await_usb_unbind(const usbip_monitor_t *monitor)
+{
+ await_usb(monitor, "unbind");
+}
+
+void usbip_monitor_await_usb_delete(const usbip_monitor_t *monitor)
+{
+ await_usb(monitor, "delete");
+}
diff --git a/tools/usb/usbip/libsrc/usbip_monitor.h b/tools/usb/usbip/libsrc/usbip_monitor.h
new file mode 100644
index 000000000000..474b95c80452
--- /dev/null
+++ b/tools/usb/usbip/libsrc/usbip_monitor.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/**
+ * Copyright (C) 2021 Lars Gunnarsson
+ */
+#ifndef __USBIP_MONITOR_H
+#define __USBIP_MONITOR_H
+
+typedef struct usbip_monitor usbip_monitor_t;
+
+usbip_monitor_t *usbip_monitor_new(void);
+void usbip_monitor_delete(usbip_monitor_t *monitor);
+
+void usbip_monitor_set_busid(usbip_monitor_t *monitor, const char *busid);
+void usbip_monitor_await_usb_add(const usbip_monitor_t *monitor,
+ const char *driver);
+void usbip_monitor_await_usb_bind(const usbip_monitor_t *monitor,
+ const char *driver);
+void usbip_monitor_await_usb_unbind(const usbip_monitor_t *monitor);
+void usbip_monitor_await_usb_delete(const usbip_monitor_t *monitor);
+
+#endif /* __USBIP_MONITOR_H */
--
2.25.1