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session.c
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/*
* This file is part of the libsigrok project.
*
* Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
* Copyright (C) 2015 Daniel Elstner <daniel.kitta@gmail.com>
*
* 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 3 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 <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <glib.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
/** @cond PRIVATE */
#define LOG_PREFIX "session"
/** @endcond */
/**
* @file
*
* Creating, using, or destroying libsigrok sessions.
*/
/**
* @defgroup grp_session Session handling
*
* Creating, using, or destroying libsigrok sessions.
*
* @{
*/
struct datafeed_callback {
sr_datafeed_callback cb;
void *cb_data;
};
/** Custom GLib event source for generic descriptor I/O.
* @see https://developer.gnome.org/glib/stable/glib-The-Main-Event-Loop.html
*/
struct fd_source {
GSource base;
int64_t timeout_us;
int64_t due_us;
/* Meta-data needed to keep track of installed sources */
struct sr_session *session;
void *key;
GPollFD pollfd;
};
/** FD event source prepare() method.
* This is called immediately before poll().
*/
static gboolean fd_source_prepare(GSource *source, int *timeout)
{
int64_t now_us;
struct fd_source *fsource;
int remaining_ms;
fsource = (struct fd_source *)source;
if (fsource->timeout_us >= 0) {
now_us = g_source_get_time(source);
if (fsource->due_us == 0) {
/* First-time initialization of the expiration time */
fsource->due_us = now_us + fsource->timeout_us;
}
remaining_ms = (MAX(0, fsource->due_us - now_us) + 999) / 1000;
} else {
remaining_ms = -1;
}
*timeout = remaining_ms;
return (remaining_ms == 0);
}
/** FD event source check() method.
* This is called after poll() returns to check whether an event fired.
*/
static gboolean fd_source_check(GSource *source)
{
struct fd_source *fsource;
unsigned int revents;
fsource = (struct fd_source *)source;
revents = fsource->pollfd.revents;
return (revents != 0 || (fsource->timeout_us >= 0
&& fsource->due_us <= g_source_get_time(source)));
}
/** FD event source dispatch() method.
* This is called if either prepare() or check() returned TRUE.
*/
static gboolean fd_source_dispatch(GSource *source,
GSourceFunc callback, void *user_data)
{
struct fd_source *fsource;
unsigned int revents;
gboolean keep;
fsource = (struct fd_source *)source;
revents = fsource->pollfd.revents;
if (!callback) {
sr_err("Callback not set, cannot dispatch event.");
return G_SOURCE_REMOVE;
}
keep = (*SR_RECEIVE_DATA_CALLBACK(callback))
(fsource->pollfd.fd, revents, user_data);
if (fsource->timeout_us >= 0 && G_LIKELY(keep)
&& G_LIKELY(!g_source_is_destroyed(source)))
fsource->due_us = g_source_get_time(source)
+ fsource->timeout_us;
return keep;
}
/** FD event source finalize() method.
*/
static void fd_source_finalize(GSource *source)
{
struct fd_source *fsource;
fsource = (struct fd_source *)source;
sr_dbg("%s: key %p", __func__, fsource->key);
sr_session_source_destroyed(fsource->session, fsource->key, source);
}
/** Create an event source for I/O on a file descriptor.
*
* In order to maintain API compatibility, this event source also doubles
* as a timer event source.
*
* @param session The session the event source belongs to.
* @param key The key used to identify this source.
* @param fd The file descriptor or HANDLE.
* @param events Events.
* @param timeout_ms The timeout interval in ms, or -1 to wait indefinitely.
*
* @return A new event source object, or NULL on failure.
*/
static GSource *fd_source_new(struct sr_session *session, void *key,
gintptr fd, int events, int timeout_ms)
{
static GSourceFuncs fd_source_funcs = {
.prepare = &fd_source_prepare,
.check = &fd_source_check,
.dispatch = &fd_source_dispatch,
.finalize = &fd_source_finalize
};
GSource *source;
struct fd_source *fsource;
source = g_source_new(&fd_source_funcs, sizeof(struct fd_source));
fsource = (struct fd_source *)source;
g_source_set_name(source, (fd < 0) ? "timer" : "fd");
if (timeout_ms >= 0) {
fsource->timeout_us = 1000 * (int64_t)timeout_ms;
fsource->due_us = 0;
} else {
fsource->timeout_us = -1;
fsource->due_us = INT64_MAX;
}
fsource->session = session;
fsource->key = key;
fsource->pollfd.fd = fd;
fsource->pollfd.events = events;
fsource->pollfd.revents = 0;
if (fd >= 0)
g_source_add_poll(source, &fsource->pollfd);
return source;
}
/**
* Create a new session.
*
* @param ctx The context in which to create the new session.
* @param new_session This will contain a pointer to the newly created
* session if the return value is SR_OK, otherwise the value
* is undefined and should not be used. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid argument.
*
* @since 0.4.0
*/
SR_API int sr_session_new(struct sr_context *ctx,
struct sr_session **new_session)
{
struct sr_session *session;
if (!new_session)
return SR_ERR_ARG;
session = g_malloc0(sizeof(struct sr_session));
session->ctx = ctx;
g_mutex_init(&session->main_mutex);
/* To maintain API compatibility, we need a lookup table
* which maps poll_object IDs to GSource* pointers.
*/
session->event_sources = g_hash_table_new(NULL, NULL);
*new_session = session;
return SR_OK;
}
/**
* Destroy a session.
* This frees up all memory used by the session.
*
* @param session The session to destroy. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid session passed.
*
* @since 0.4.0
*/
SR_API int sr_session_destroy(struct sr_session *session)
{
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
sr_session_dev_remove_all(session);
g_slist_free_full(session->owned_devs, (GDestroyNotify)sr_dev_inst_free);
sr_session_datafeed_callback_remove_all(session);
g_hash_table_unref(session->event_sources);
g_mutex_clear(&session->main_mutex);
g_free(session);
return SR_OK;
}
/**
* Remove all the devices from a session.
*
* The session itself (i.e., the struct sr_session) is not free'd and still
* exists after this function returns.
*
* @param session The session to use. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_BUG Invalid session passed.
*
* @since 0.4.0
*/
SR_API int sr_session_dev_remove_all(struct sr_session *session)
{
struct sr_dev_inst *sdi;
GSList *l;
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
for (l = session->devs; l; l = l->next) {
sdi = (struct sr_dev_inst *) l->data;
sdi->session = NULL;
}
g_slist_free(session->devs);
session->devs = NULL;
return SR_OK;
}
/**
* Add a device instance to a session.
*
* @param session The session to add to. Must not be NULL.
* @param sdi The device instance to add to a session. Must not
* be NULL. Also, sdi->driver and sdi->driver->dev_open must
* not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid argument.
*
* @since 0.4.0
*/
SR_API int sr_session_dev_add(struct sr_session *session,
struct sr_dev_inst *sdi)
{
int ret;
if (!sdi) {
sr_err("%s: sdi was NULL", __func__);
return SR_ERR_ARG;
}
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
/* If sdi->session is not NULL, the device is already in this or
* another session. */
if (sdi->session) {
sr_err("%s: already assigned to session", __func__);
return SR_ERR_ARG;
}
/* If sdi->driver is NULL, this is a virtual device. */
if (!sdi->driver) {
/* Just add the device, don't run dev_open(). */
session->devs = g_slist_append(session->devs, sdi);
sdi->session = session;
return SR_OK;
}
/* sdi->driver is non-NULL (i.e. we have a real device). */
if (!sdi->driver->dev_open) {
sr_err("%s: sdi->driver->dev_open was NULL", __func__);
return SR_ERR_BUG;
}
session->devs = g_slist_append(session->devs, sdi);
sdi->session = session;
/* TODO: This is invalid if the session runs in a different thread.
* The usage semantics and restrictions need to be documented.
*/
if (session->running) {
/* Adding a device to a running session. Commit settings
* and start acquisition on that device now. */
if ((ret = sr_config_commit(sdi)) != SR_OK) {
sr_err("Failed to commit device settings before "
"starting acquisition in running session (%s)",
sr_strerror(ret));
return ret;
}
if ((ret = sr_dev_acquisition_start(sdi)) != SR_OK) {
sr_err("Failed to start acquisition of device in "
"running session (%s)", sr_strerror(ret));
return ret;
}
}
return SR_OK;
}
/**
* List all device instances attached to a session.
*
* @param session The session to use. Must not be NULL.
* @param devlist A pointer where the device instance list will be
* stored on return. If no devices are in the session,
* this will be NULL. Each element in the list points
* to a struct sr_dev_inst *.
* The list must be freed by the caller, but not the
* elements pointed to.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid argument.
*
* @since 0.4.0
*/
SR_API int sr_session_dev_list(struct sr_session *session, GSList **devlist)
{
if (!session)
return SR_ERR_ARG;
if (!devlist)
return SR_ERR_ARG;
*devlist = g_slist_copy(session->devs);
return SR_OK;
}
/**
* Remove a device instance from a session.
*
* @param session The session to remove from. Must not be NULL.
* @param sdi The device instance to remove from a session. Must not
* be NULL. Also, sdi->driver and sdi->driver->dev_open must
* not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid argument.
*
* @since 0.4.0
*/
SR_API int sr_session_dev_remove(struct sr_session *session,
struct sr_dev_inst *sdi)
{
if (!sdi) {
sr_err("%s: sdi was NULL", __func__);
return SR_ERR_ARG;
}
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
/* If sdi->session is not session, the device is not in this
* session. */
if (sdi->session != session) {
sr_err("%s: not assigned to this session", __func__);
return SR_ERR_ARG;
}
session->devs = g_slist_remove(session->devs, sdi);
sdi->session = NULL;
return SR_OK;
}
/**
* Remove all datafeed callbacks in a session.
*
* @param session The session to use. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid session passed.
*
* @since 0.4.0
*/
SR_API int sr_session_datafeed_callback_remove_all(struct sr_session *session)
{
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
g_slist_free_full(session->datafeed_callbacks, g_free);
session->datafeed_callbacks = NULL;
return SR_OK;
}
/**
* Add a datafeed callback to a session.
*
* @param session The session to use. Must not be NULL.
* @param cb Function to call when a chunk of data is received.
* Must not be NULL.
* @param cb_data Opaque pointer passed in by the caller.
*
* @retval SR_OK Success.
* @retval SR_ERR_BUG No session exists.
*
* @since 0.3.0
*/
SR_API int sr_session_datafeed_callback_add(struct sr_session *session,
sr_datafeed_callback cb, void *cb_data)
{
struct datafeed_callback *cb_struct;
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_BUG;
}
if (!cb) {
sr_err("%s: cb was NULL", __func__);
return SR_ERR_ARG;
}
cb_struct = g_malloc0(sizeof(struct datafeed_callback));
cb_struct->cb = cb;
cb_struct->cb_data = cb_data;
session->datafeed_callbacks =
g_slist_append(session->datafeed_callbacks, cb_struct);
return SR_OK;
}
/**
* Get the trigger assigned to this session.
*
* @param session The session to use.
*
* @retval NULL Invalid (NULL) session was passed to the function.
* @retval other The trigger assigned to this session (can be NULL).
*
* @since 0.4.0
*/
SR_API struct sr_trigger *sr_session_trigger_get(struct sr_session *session)
{
if (!session)
return NULL;
return session->trigger;
}
/**
* Set the trigger of this session.
*
* @param session The session to use. Must not be NULL.
* @param trig The trigger to assign to this session. Can be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid argument.
*
* @since 0.4.0
*/
SR_API int sr_session_trigger_set(struct sr_session *session, struct sr_trigger *trig)
{
if (!session)
return SR_ERR_ARG;
session->trigger = trig;
return SR_OK;
}
static int verify_trigger(struct sr_trigger *trigger)
{
struct sr_trigger_stage *stage;
struct sr_trigger_match *match;
GSList *l, *m;
if (!trigger->stages) {
sr_err("No trigger stages defined.");
return SR_ERR;
}
sr_spew("Checking trigger:");
for (l = trigger->stages; l; l = l->next) {
stage = l->data;
if (!stage->matches) {
sr_err("Stage %d has no matches defined.", stage->stage);
return SR_ERR;
}
for (m = stage->matches; m; m = m->next) {
match = m->data;
if (!match->channel) {
sr_err("Stage %d match has no channel.", stage->stage);
return SR_ERR;
}
if (!match->match) {
sr_err("Stage %d match is not defined.", stage->stage);
return SR_ERR;
}
sr_spew("Stage %d match on channel %s, match %d", stage->stage,
match->channel->name, match->match);
}
}
return SR_OK;
}
/** Set up the main context the session will be executing in.
*
* Must be called just before the session starts, by the thread which
* will execute the session main loop. Once acquired, the main context
* pointer is immutable for the duration of the session run.
*/
static int set_main_context(struct sr_session *session)
{
GMainContext *main_context;
g_mutex_lock(&session->main_mutex);
/* May happen if sr_session_start() is called a second time
* while the session is still running.
*/
if (session->main_context) {
sr_err("Main context already set.");
g_mutex_unlock(&session->main_mutex);
return SR_ERR;
}
main_context = g_main_context_ref_thread_default();
/*
* Try to use an existing main context if possible, but only if we
* can make it owned by the current thread. Otherwise, create our
* own main context so that event source callbacks can execute in
* the session thread.
*/
if (g_main_context_acquire(main_context)) {
g_main_context_release(main_context);
sr_dbg("Using thread-default main context.");
} else {
g_main_context_unref(main_context);
sr_dbg("Creating our own main context.");
main_context = g_main_context_new();
}
session->main_context = main_context;
g_mutex_unlock(&session->main_mutex);
return SR_OK;
}
/** Unset the main context used for the current session run.
*
* Must be called right after stopping the session. Note that if the
* session is stopped asynchronously, the main loop may still be running
* after the main context has been unset. This is OK as long as no new
* event sources are created -- the main loop holds its own reference
* to the main context.
*/
static int unset_main_context(struct sr_session *session)
{
int ret;
g_mutex_lock(&session->main_mutex);
if (session->main_context) {
g_main_context_unref(session->main_context);
session->main_context = NULL;
ret = SR_OK;
} else {
/* May happen if the set/unset calls are not matched.
*/
sr_err("No main context to unset.");
ret = SR_ERR;
}
g_mutex_unlock(&session->main_mutex);
return ret;
}
static unsigned int session_source_attach(struct sr_session *session,
GSource *source)
{
unsigned int id = 0;
g_mutex_lock(&session->main_mutex);
if (session->main_context)
id = g_source_attach(source, session->main_context);
else
sr_err("Cannot add event source without main context.");
g_mutex_unlock(&session->main_mutex);
return id;
}
/* Idle handler; invoked when the number of registered event sources
* for a running session drops to zero.
*/
static gboolean delayed_stop_check(void *data)
{
struct sr_session *session;
session = data;
session->stop_check_id = 0;
/* Session already ended? */
if (!session->running)
return G_SOURCE_REMOVE;
/* New event sources may have been installed in the meantime. */
if (g_hash_table_size(session->event_sources) != 0)
return G_SOURCE_REMOVE;
session->running = FALSE;
unset_main_context(session);
sr_info("Stopped.");
/* This indicates a bug in user code, since it is not valid to
* restart or destroy a session while it may still be running.
*/
if (!session->main_loop && !session->stopped_callback) {
sr_err("BUG: Session stop left unhandled.");
return G_SOURCE_REMOVE;
}
if (session->main_loop)
g_main_loop_quit(session->main_loop);
if (session->stopped_callback)
(*session->stopped_callback)(session->stopped_cb_data);
return G_SOURCE_REMOVE;
}
static int stop_check_later(struct sr_session *session)
{
GSource *source;
unsigned int source_id;
if (session->stop_check_id != 0)
return SR_OK; /* idle handler already installed */
source = g_idle_source_new();
g_source_set_callback(source, &delayed_stop_check, session, NULL);
source_id = session_source_attach(session, source);
session->stop_check_id = source_id;
g_source_unref(source);
return (source_id != 0) ? SR_OK : SR_ERR;
}
/**
* Start a session.
*
* When this function returns with a status code indicating success, the
* session is running. Use sr_session_stopped_callback_set() to receive
* notification upon completion, or call sr_session_run() to block until
* the session stops.
*
* Session events will be processed in the context of the current thread.
* If a thread-default GLib main context has been set, and is not owned by
* any other thread, it will be used. Otherwise, libsigrok will create its
* own main context for the current thread.
*
* @param session The session to use. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid session passed.
* @retval SR_ERR Other error.
*
* @since 0.4.0
*/
SR_API int sr_session_start(struct sr_session *session)
{
struct sr_dev_inst *sdi;
struct sr_channel *ch;
GSList *l, *c, *lend;
int ret;
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
if (!session->devs) {
sr_err("%s: session->devs was NULL; a session "
"cannot be started without devices.", __func__);
return SR_ERR_ARG;
}
if (session->running) {
sr_err("Cannot (re-)start session while it is still running.");
return SR_ERR;
}
if (session->trigger) {
ret = verify_trigger(session->trigger);
if (ret != SR_OK)
return ret;
}
/* Check enabled channels and commit settings of all devices. */
for (l = session->devs; l; l = l->next) {
sdi = l->data;
for (c = sdi->channels; c; c = c->next) {
ch = c->data;
if (ch->enabled)
break;
}
if (!c) {
sr_err("%s device %s has no enabled channels.",
sdi->driver->name, sdi->connection_id);
return SR_ERR;
}
ret = sr_config_commit(sdi);
if (ret != SR_OK) {
sr_err("Failed to commit %s device %s settings "
"before starting acquisition.",
sdi->driver->name, sdi->connection_id);
return ret;
}
}
ret = set_main_context(session);
if (ret != SR_OK)
return ret;
sr_info("Starting.");
session->running = TRUE;
/* Have all devices start acquisition. */
for (l = session->devs; l; l = l->next) {
if (!(sdi = l->data)) {
sr_err("Device sdi was NULL, can't start session.");
ret = SR_ERR;
break;
}
ret = sr_dev_acquisition_start(sdi);
if (ret != SR_OK) {
sr_err("Could not start %s device %s acquisition.",
sdi->driver->name, sdi->connection_id);
break;
}
}
if (ret != SR_OK) {
/* If there are multiple devices, some of them may already have
* started successfully. Stop them now before returning. */
lend = l->next;
for (l = session->devs; l != lend; l = l->next) {
sdi = l->data;
sr_dev_acquisition_stop(sdi);
}
/* TODO: Handle delayed stops. Need to iterate the event
* sources... */
session->running = FALSE;
unset_main_context(session);
return ret;
}
if (g_hash_table_size(session->event_sources) == 0)
stop_check_later(session);
return SR_OK;
}
/**
* Block until the running session stops.
*
* This is a convenience function which creates a GLib main loop and runs
* it to process session events until the session stops.
*
* Instead of using this function, applications may run their own GLib main
* loop, and use sr_session_stopped_callback_set() to receive notification
* when the session finished running.
*
* @param session The session to use. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid session passed.
* @retval SR_ERR Other error.
*
* @since 0.4.0
*/
SR_API int sr_session_run(struct sr_session *session)
{
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
if (!session->running) {
sr_err("No session running.");
return SR_ERR;
}
if (session->main_loop) {
sr_err("Main loop already created.");
return SR_ERR;
}
g_mutex_lock(&session->main_mutex);
if (!session->main_context) {
sr_err("Cannot run without main context.");
g_mutex_unlock(&session->main_mutex);
return SR_ERR;
}
session->main_loop = g_main_loop_new(session->main_context, FALSE);
g_mutex_unlock(&session->main_mutex);
g_main_loop_run(session->main_loop);
g_main_loop_unref(session->main_loop);
session->main_loop = NULL;
return SR_OK;
}
static gboolean session_stop_sync(void *user_data)
{
struct sr_session *session;
struct sr_dev_inst *sdi;
GSList *node;
session = user_data;
if (!session->running)
return G_SOURCE_REMOVE;
sr_info("Stopping.");
for (node = session->devs; node; node = node->next) {
sdi = node->data;
sr_dev_acquisition_stop(sdi);
}
return G_SOURCE_REMOVE;
}
/**
* Stop a session.
*
* This requests the drivers of each device participating in the session to
* abort the acquisition as soon as possible. Even after this function returns,
* event processing still continues until all devices have actually stopped.
*
* Use sr_session_stopped_callback_set() to receive notification when the event
* processing finished.
*
* This function is reentrant. That is, it may be called from a different
* thread than the one executing the session, as long as it can be ensured
* that the session object is valid.
*
* If the session is not running, sr_session_stop() silently does nothing.
*
* @param session The session to use. Must not be NULL.
*
* @retval SR_OK Success.
* @retval SR_ERR_ARG Invalid session passed.
*
* @since 0.4.0
*/
SR_API int sr_session_stop(struct sr_session *session)
{
GMainContext *main_context;
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
g_mutex_lock(&session->main_mutex);
main_context = (session->main_context)
? g_main_context_ref(session->main_context)
: NULL;
g_mutex_unlock(&session->main_mutex);
if (!main_context) {
sr_dbg("No main context set; already stopped?");
/* Not an error; as it would be racy. */
return SR_OK;
}
g_main_context_invoke(main_context, &session_stop_sync, session);
g_main_context_unref(main_context);
return SR_OK;
}
/**
* Return whether the session is currently running.
*
* Note that this function should be called from the same thread
* the session was started in.
*
* @param session The session to use. Must not be NULL.
*
* @retval TRUE Session is running.
* @retval FALSE Session is not running.
* @retval SR_ERR_ARG Invalid session passed.
*
* @since 0.4.0
*/
SR_API int sr_session_is_running(struct sr_session *session)
{
if (!session) {
sr_err("%s: session was NULL", __func__);
return SR_ERR_ARG;
}
return session->running;
}
/**
* Set the callback to be invoked after a session stopped running.
*
* Install a callback to receive notification when a session run stopped.