The branch main has been updated by bapt:
URL:
https://cgit.FreeBSD.org/src/commit/?id=9dc96d8bc3f282fefb186670edbf07c7cc32f9c5
commit 9dc96d8bc3f282fefb186670edbf07c7cc32f9c5
Author: Baptiste Daroussin <b...@freebsd.org>
AuthorDate: 2025-01-04 10:23:12 +0000
Commit: Baptiste Daroussin <b...@freebsd.org>
CommitDate: 2025-01-16 14:10:11 +0000
libusb: hotplug, use events instead of a timer when possible
Try to fetch events from nlsysevent or devd to determine when
to scan the usb bus for devices addition or removal.
if none are available fallback on the regular timer based (4s)
scanner
if devd socket or netlink socket is closed or error fallback on the
timer based method.
Reviewed by: kevans
Differential Revision: https://reviews.freebsd.org/D48300
---
lib/libusb/libusb10.c | 8 ++
lib/libusb/libusb10.h | 16 ++++
lib/libusb/libusb10_hotplug.c | 173 +++++++++++++++++++++++++++++++++++++++++-
3 files changed, 196 insertions(+), 1 deletion(-)
diff --git a/lib/libusb/libusb10.c b/lib/libusb/libusb10.c
index 6d9c11910ea0..afa25eabf459 100644
--- a/lib/libusb/libusb10.c
+++ b/lib/libusb/libusb10.c
@@ -155,6 +155,7 @@ libusb_init_context(libusb_context **context,
return (LIBUSB_ERROR_INVALID_PARAM);
memset(ctx, 0, sizeof(*ctx));
+ ctx->devd_pipe = -1;
debug = getenv("LIBUSB_DEBUG");
if (debug != NULL) {
@@ -280,6 +281,13 @@ libusb_exit(libusb_context *ctx)
HOTPLUG_LOCK(ctx);
td = ctx->hotplug_handler;
ctx->hotplug_handler = NO_THREAD;
+ if (ctx->usb_event_mode == usb_event_devd) {
+ close(ctx->devd_pipe);
+ ctx->devd_pipe = -1;
+ } else if (ctx->usb_event_mode == usb_event_netlink) {
+ close(ctx->ss.fd);
+ ctx->ss.fd = -1;
+ }
HOTPLUG_UNLOCK(ctx);
pthread_join(td, &ptr);
diff --git a/lib/libusb/libusb10.h b/lib/libusb/libusb10.h
index 544364386061..3402e0377c92 100644
--- a/lib/libusb/libusb10.h
+++ b/lib/libusb/libusb10.h
@@ -30,6 +30,12 @@
#ifndef LIBUSB_GLOBAL_INCLUDE_FILE
#include <sys/queue.h>
+#include <netlink/netlink.h>
+#include <netlink/netlink_generic.h>
+#include <netlink/netlink_snl.h>
+#include <netlink/netlink_snl_generic.h>
+#include <netlink/netlink_sysevent.h>
+
#endif
#define GET_CONTEXT(ctx) (((ctx) == NULL) ? usbi_default_context :
(ctx))
@@ -90,12 +96,22 @@ struct libusb_hotplug_callback_handle_struct {
TAILQ_HEAD(libusb_device_head, libusb_device);
+typedef enum {
+ usb_event_none,
+ usb_event_scan,
+ usb_event_devd,
+ usb_event_netlink
+} usb_event_mode_t;
+
struct libusb_context {
int debug;
int debug_fixed;
int ctrl_pipe[2];
int tr_done_ref;
int tr_done_gen;
+ usb_event_mode_t usb_event_mode;
+ int devd_pipe;
+ struct snl_state ss;
pthread_mutex_t ctx_lock;
pthread_mutex_t hotplug_lock;
diff --git a/lib/libusb/libusb10_hotplug.c b/lib/libusb/libusb10_hotplug.c
index 98903686f76b..fd016e972dfb 100644
--- a/lib/libusb/libusb10_hotplug.c
+++ b/lib/libusb/libusb10_hotplug.c
@@ -23,6 +23,7 @@
* SUCH DAMAGE.
*/
+#include <netlink/netlink_snl_generic.h>
#ifdef LIBUSB_GLOBAL_INCLUDE_FILE
#include LIBUSB_GLOBAL_INCLUDE_FILE
#else
@@ -39,6 +40,10 @@
#include <sys/ioctl.h>
#include <sys/queue.h>
#include <sys/endian.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/module.h>
+#include <sys/linker.h>
#endif
#define libusb_device_handle libusb20_device
@@ -49,6 +54,118 @@
#include "libusb.h"
#include "libusb10.h"
+#define DEVDPIPE "/var/run/devd.seqpacket.pipe"
+#define DEVCTL_MAXBUF 1024
+
+typedef enum {
+ broken_event,
+ invalid_event,
+ valid_event,
+} event_t;
+
+static bool
+netlink_init(libusb_context *ctx)
+{
+ struct _getfamily_attrs attrs;
+
+ if (modfind("nlsysevent") < 0)
+ kldload("nlsysevent");
+ if (modfind("nlsysevent") < 0)
+ return (false);
+ if (!snl_init(&ctx->ss, NETLINK_GENERIC))
+ return (false);
+
+ if (!snl_get_genl_family_info(&ctx->ss, "nlsysevent", &attrs))
+ return (false);
+
+ for (unsigned int i = 0; i < attrs.mcast_groups.num_groups; i++) {
+ if (strcmp(attrs.mcast_groups.groups[i]->mcast_grp_name,
+ "USB") == 0) {
+ if (setsockopt(ctx->ss.fd, SOL_NETLINK,
+ NETLINK_ADD_MEMBERSHIP,
+ &attrs.mcast_groups.groups[i]->mcast_grp_id,
+ sizeof(attrs.mcast_groups.groups[i]->mcast_grp_id))
+ == -1) {
+ return (false);
+ }
+ }
+ }
+ ctx->usb_event_mode = usb_event_netlink;
+ return (true);
+}
+
+static bool
+devd_init(libusb_context *ctx)
+{
+ struct sockaddr_un devd_addr;
+
+ bzero(&devd_addr, sizeof(devd_addr));
+ if ((ctx->devd_pipe = socket(PF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK,
0)) < 0)
+ return (false);
+
+ devd_addr.sun_family = PF_LOCAL;
+ strlcpy(devd_addr.sun_path, DEVDPIPE, sizeof(devd_addr.sun_path));
+ if (connect(ctx->devd_pipe, (struct sockaddr *)&devd_addr,
+ sizeof(devd_addr)) == -1) {
+ close(ctx->devd_pipe);
+ ctx->devd_pipe = -1;
+ return (false);
+ }
+
+ ctx->usb_event_mode = usb_event_devd;
+ return (true);
+}
+
+struct nlevent {
+ const char *name;
+ const char *subsystem;
+ const char *type;
+ const char *data;
+};
+
+#define _OUT(_field) offsetof(struct nlevent, _field)
+static struct snl_attr_parser ap_nlevent_get[] = {
+ { .type = NLSE_ATTR_SYSTEM, .off = _OUT(name), .cb =
snl_attr_get_string },
+ { .type = NLSE_ATTR_SUBSYSTEM, .off = _OUT(subsystem), .cb =
snl_attr_get_string },
+ { .type = NLSE_ATTR_TYPE, .off = _OUT(type), .cb = snl_attr_get_string
},
+ { .type = NLSE_ATTR_DATA, .off = _OUT(data), .cb = snl_attr_get_string
},
+};
+#undef _OUT
+
+SNL_DECLARE_GENL_PARSER(nlevent_get_parser, ap_nlevent_get);
+
+static event_t
+verify_event_validity(libusb_context *ctx)
+{
+ if (ctx->usb_event_mode == usb_event_netlink) {
+ struct nlmsghdr *hdr;
+ struct nlevent ne;
+
+ hdr = snl_read_message(&ctx->ss);
+ if (hdr != NULL && hdr->nlmsg_type != NLMSG_ERROR) {
+ memset(&ne, 0, sizeof(ne));
+ if (!snl_parse_nlmsg(&ctx->ss, hdr,
&nlevent_get_parser, &ne))
+ return (broken_event);
+ if (strcmp(ne.subsystem, "DEVICE") == 0)
+ return (valid_event);
+ return (invalid_event);
+ }
+ return (invalid_event);
+ } else if (ctx->usb_event_mode == usb_event_devd) {
+ char buf[DEVCTL_MAXBUF];
+ ssize_t len;
+
+ len = read(ctx->devd_pipe, buf, sizeof(buf));
+ if (len == 0 || (len < 0 && errno != EWOULDBLOCK))
+ return (broken_event);
+ if (len > 0 && strstr(buf, "system=USB") != NULL &&
+ strstr(buf, "subsystem=DEVICE") != NULL)
+ return (valid_event);
+ return (invalid_event);
+ }
+ return (broken_event);
+}
+
static int
libusb_hotplug_equal(libusb_device *_adev, libusb_device *_bdev)
{
@@ -105,6 +222,7 @@ libusb_hotplug_enumerate(libusb_context *ctx, struct
libusb_device_head *phead)
static void *
libusb_hotplug_scan(void *arg)
{
+ struct pollfd pfd;
struct libusb_device_head hotplug_devs;
libusb_hotplug_callback_handle acbh;
libusb_hotplug_callback_handle bcbh;
@@ -112,9 +230,51 @@ libusb_hotplug_scan(void *arg)
libusb_device *temp;
libusb_device *adev;
libusb_device *bdev;
+ int timeout = INFTIM;
+ int nfds;
+ memset(&pfd, 0, sizeof(pfd));
+ if (ctx->usb_event_mode == usb_event_devd) {
+ pfd.fd = ctx->devd_pipe;
+ pfd.events = POLLIN | POLLERR;
+ nfds = 1;
+ } else if (ctx->usb_event_mode == usb_event_netlink) {
+ pfd.fd = ctx->ss.fd;
+ pfd.events = POLLIN | POLLERR;
+ nfds = 1;
+ } else {
+ nfds = 0;
+ timeout = 4000;
+ }
for (;;) {
- usleep(4000000);
+ pfd.revents = 0;
+ if (poll(&pfd, nfds, timeout) > 0) {
+ switch (verify_event_validity(ctx)) {
+ case invalid_event:
+ continue;
+ case valid_event:
+ break;
+ case broken_event:
+ /* There are 2 cases for broken events:
+ * - devd and netlink sockets are not available
+ * anymore (devd restarted, nlsysevent
unloaded)
+ * - libusb_exit has been called as it sets
NO_THREAD
+ * this will result in exiting this loop and
this thread
+ * immediately
+ */
+ nfds = 0;
+ if (ctx->usb_event_mode == usb_event_devd) {
+ if (ctx->devd_pipe != -1)
+ close(ctx->devd_pipe);
+ } else if (ctx->usb_event_mode ==
usb_event_netlink) {
+ if (ctx->ss.fd != -1)
+ close(ctx->ss.fd);
+ }
+ ctx->usb_event_mode = usb_event_scan;
+ timeout = 4000;
+ break;
+ }
+ }
HOTPLUG_LOCK(ctx);
if (ctx->hotplug_handler == NO_THREAD) {
@@ -122,6 +282,10 @@ libusb_hotplug_scan(void *arg)
TAILQ_REMOVE(&ctx->hotplug_devs, adev,
hotplug_entry);
libusb_unref_device(adev);
}
+ if (ctx->usb_event_mode == usb_event_devd)
+ close(ctx->devd_pipe);
+ else if (ctx->usb_event_mode == usb_event_netlink)
+ close(ctx->ss.fd);
HOTPLUG_UNLOCK(ctx);
break;
}
@@ -192,6 +356,13 @@ int libusb_hotplug_register_callback(libusb_context *ctx,
ctx = GET_CONTEXT(ctx);
+ if (ctx->usb_event_mode == usb_event_none) {
+ HOTPLUG_LOCK(ctx);
+ if (!netlink_init(ctx) && !devd_init(ctx))
+ ctx->usb_event_mode = usb_event_scan;
+ HOTPLUG_UNLOCK(ctx);
+ }
+
if (ctx == NULL || cb_fn == NULL || events == 0 ||
vendor_id < -1 || vendor_id > 0xffff ||
product_id < -1 || product_id > 0xffff ||
