libosmocore libusb integration
Osmocom applications typically use libosmocore select.[ch] event loop
code as their main event dispatch mechanism. When they want to deal
with libusb in a non-blocking/asynchronous way, they need to integrate
libusb into that select().
The new libosmousb is doing exactly that: Providing a shared utility
library for Osmocom programs that wish to use libusb. This is useful
for example in simtrace2 host utilitie as well as osmo-e1d.
Change-Id: I656a1a38cbb5b1f3a9145d2869d3b4d0adefcae3
Closes: OS#4299
diff --git a/src/usb/Makefile.am b/src/usb/Makefile.am
new file mode 100644
index 0000000..bca39bf
--- /dev/null
+++ b/src/usb/Makefile.am
@@ -0,0 +1,21 @@
+# This is _NOT_ the library release version, it's an API version.
+# Please read chapter "Library interface versions" of the libtool documentation
+# before making any modifications: https://www.gnu.org/software/libtool/manual/html_node/Versioning.html
+LIBVERSION=0:0:0
+
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)/include
+AM_CFLAGS = -fPIC -Wall $(LIBUSB_CFLAGS) $(TALLOC_CFLAGS)
+AM_LDFLAGS = $(COVERAGE_LDFLAGS)
+
+if ENABLE_LIBUSB
+
+lib_LTLIBRARIES = libosmousb.la
+
+libosmousb_la_SOURCES = osmo_libusb.c
+libosmosim_la_LDFLAGS = -version-info $(LIBVERSION)
+libosmosim_la_LIBADD = \
+ $(top_builddir)/src/libosmocore.la \
+ $(TALLOC_LIBS) \
+ $(LIBUSB_LIBS)
+
+endif
diff --git a/src/usb/osmo_libusb.c b/src/usb/osmo_libusb.c
new file mode 100644
index 0000000..fda9573
--- /dev/null
+++ b/src/usb/osmo_libusb.c
@@ -0,0 +1,137 @@
+/* libosmocore integration with libusb-1.0
+ *
+ * (C) 2019 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <poll.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/talloc.h>
+
+#include <libusb.h>
+
+/***********************************************************************
+ * logging integration
+ ***********************************************************************/
+
+#define DLUSB DLINP
+
+#ifdef LIBUSB_LOG_CB_CONTEXT /* introduced in 1.0.23 */
+static const int usb2logl[] = {
+ [LIBUSB_LOG_LEVEL_NONE] = LOGL_FATAL,
+ [LIBUSB_LOG_LEVEL_ERROR] = LOGL_ERROR,
+ [LIBUSB_LOG_LEVEL_WARNING] = LOGL_NOTICE,
+ [LIBUSB_LOG_LEVEL_INFO] = LOGL_INFO,
+ [LIBUSB_LOG_LEVEL_DEBUG] = LOGL_DEBUG,
+};
+
+/* called by libusb if it wants to log something */
+static void libosmo_usb_log_cb(libusb_context *luctx, enum libusb_log_level level_usb, const char *str)
+{
+ int level = LOGL_NOTICE;
+
+ if (level_usb < ARRAY_SIZE(usb2logl))
+ level = usb2logl[level_usb];
+
+ LOGP(DLUSB, level, "%s", str);
+}
+#endif /* LIBUSB_LOG_CB_CONTEXT */
+
+/***********************************************************************
+ * select loop integration
+ ***********************************************************************/
+
+static int osmo_usb_fd_cb(struct osmo_fd *ofd, unsigned int what)
+{
+ libusb_context *luctx = ofd->data;
+
+ /* we assume that we're running Linux v2.6.27 with timerfd support here
+ * and hence don't have to perform manual timeout handling. See
+ * "Notes on time-based events" at
+ * http://libusb.sourceforge.net/api-1.0/group__libusb__poll.html */
+ struct timeval zero_tv = { 0, 0 };
+ libusb_handle_events_timeout(luctx, &zero_tv);
+
+ return 0;
+}
+
+/* called by libusb if it wants to add a file-descriptor */
+static void osmo_usb_added_cb(int fd, short events, void *user_data)
+{
+ struct osmo_fd *ofd = talloc_zero(OTC_GLOBAL, struct osmo_fd);
+ libusb_context *luctx = user_data;
+ unsigned int when = 0;
+
+ if (events & POLLIN)
+ when |= OSMO_FD_READ;
+ if (events & POLLOUT)
+ when |= OSMO_FD_WRITE;
+
+ osmo_fd_setup(ofd, fd, when, osmo_usb_fd_cb, luctx, 0);
+ osmo_fd_register(ofd);
+}
+
+/* called by libusb if it wants to remove a file-descriptor */
+static void osmo_usb_removed_cb(int fd, void *user_data)
+{
+ struct osmo_fd *ofd = osmo_fd_get_by_fd(fd);
+ if (!fd)
+ return;
+ osmo_fd_unregister(ofd);
+ talloc_free(ofd);
+}
+
+
+/***********************************************************************
+ * initialization
+ ***********************************************************************/
+
+int osmo_libusb_init(libusb_context **pluctx)
+{
+ libusb_context *luctx = NULL;
+ int rc;
+
+ rc = libusb_init(pluctx);
+ if (rc != 0)
+ return rc;
+
+ if (pluctx)
+ luctx = *pluctx;
+
+#ifdef LIBUSB_LOG_CB_CONTEXT /* introduced in 1.0.23 */
+ libusb_set_log_cb(luctx, &libosmo_usb_log_cb, LIBUSB_LOG_CB_CONTEXT);
+#endif
+
+ libusb_set_pollfd_notifiers(luctx, osmo_usb_added_cb, osmo_usb_removed_cb, luctx);
+
+ return 0;
+}
+
+void osmo_libusb_exit(libusb_context *luctx)
+{
+ /* we just assume libusb is cleaning up all the osmo_Fd's we've allocated */
+ libusb_exit(luctx);
+}