X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Ftracepoint.c;h=b109fe30152b2968f7aba03736bab0cae53dbd89;hb=HEAD;hp=526ee00e58d130cd2093ab59e31078b7cdbf52b4;hpb=596c4223bf063ebc06262c08896c596326d036e6;p=lttng-ust.git

diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
deleted file mode 100644
index 526ee00e..00000000
--- a/liblttng-ust/tracepoint.c
+++ /dev/null
@@ -1,673 +0,0 @@
-/*
- * Copyright (C) 2008-2011 Mathieu Desnoyers
- * Copyright (C) 2009 Pierre-Marc Fournier
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
- *
- * Ported to userspace by Pierre-Marc Fournier.
- */
-
-#define _LGPL_SOURCE
-#include <errno.h>
-#include <lttng/tracepoint.h>
-#include <lttng/core.h>
-#include <stdint.h>
-#include <stddef.h>
-#include <urcu/arch.h>
-#include <urcu-bp.h>
-#include <urcu/hlist.h>
-#include <urcu/uatomic.h>
-#include <urcu/compiler.h>
-
-#include <lttng/usterr-signal-safe.h>
-#include "tracepoint-internal.h"
-#include "ltt-tracer-core.h"
-#include "jhash.h"
-
-/* Set to 1 to enable tracepoint debug output */
-static const int tracepoint_debug;
-static int initialized;
-static void (*new_tracepoint_cb)(struct tracepoint *);
-
-/* libraries that contain tracepoints (struct tracepoint_lib) */
-static CDS_LIST_HEAD(libs);
-
-/*
- * The UST lock protects the library tracepoints, the hash table, and
- * the library list.
- * All calls to the tracepoint API must be protected by the UST lock,
- * excepts calls to tracepoint_register_lib and
- * tracepoint_unregister_lib, which take the UST lock themselves.
- */
-
-/*
- * Tracepoint hash table, containing the active tracepoints.
- * Protected by tracepoints_mutex.
- */
-#define TRACEPOINT_HASH_BITS 6
-#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
-static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
-
-static CDS_LIST_HEAD(old_probes);
-static int need_update;
-
-/*
- * Note about RCU :
- * It is used to to delay the free of multiple probes array until a quiescent
- * state is reached.
- * Tracepoint entries modifications are protected by the tracepoints_mutex.
- */
-struct tracepoint_entry {
-	struct cds_hlist_node hlist;
-	struct tracepoint_probe *probes;
-	int refcount;	/* Number of times armed. 0 if disarmed. */
-	char name[0];
-};
-
-struct tp_probes {
-	union {
-		struct cds_list_head list;
-	} u;
-	struct tracepoint_probe probes[0];
-};
-
-static inline void *allocate_probes(int count)
-{
-	struct tp_probes *p  = zmalloc(count * sizeof(struct tracepoint_probe)
-			+ sizeof(struct tp_probes));
-	return p == NULL ? NULL : p->probes;
-}
-
-static inline void release_probes(void *old)
-{
-	if (old) {
-		struct tp_probes *tp_probes = caa_container_of(old,
-			struct tp_probes, probes[0]);
-		synchronize_rcu();
-		free(tp_probes);
-	}
-}
-
-static void debug_print_probes(struct tracepoint_entry *entry)
-{
-	int i;
-
-	if (!tracepoint_debug || !entry->probes)
-		return;
-
-	for (i = 0; entry->probes[i].func; i++)
-		DBG("Probe %d : %p", i, entry->probes[i].func);
-}
-
-static void *
-tracepoint_entry_add_probe(struct tracepoint_entry *entry,
-			   void *probe, void *data)
-{
-	int nr_probes = 0;
-	struct tracepoint_probe *old, *new;
-
-	WARN_ON(!probe);
-
-	debug_print_probes(entry);
-	old = entry->probes;
-	if (old) {
-		/* (N -> N+1), (N != 0, 1) probes */
-		for (nr_probes = 0; old[nr_probes].func; nr_probes++)
-			if (old[nr_probes].func == probe &&
-			    old[nr_probes].data == data)
-				return ERR_PTR(-EEXIST);
-	}
-	/* + 2 : one for new probe, one for NULL func */
-	new = allocate_probes(nr_probes + 2);
-	if (new == NULL)
-		return ERR_PTR(-ENOMEM);
-	if (old)
-		memcpy(new, old, nr_probes * sizeof(struct tracepoint_probe));
-	new[nr_probes].func = probe;
-	new[nr_probes].data = data;
-	new[nr_probes + 1].func = NULL;
-	entry->refcount = nr_probes + 1;
-	entry->probes = new;
-	debug_print_probes(entry);
-	return old;
-}
-
-static void *
-tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe,
-			      void *data)
-{
-	int nr_probes = 0, nr_del = 0, i;
-	struct tracepoint_probe *old, *new;
-
-	old = entry->probes;
-
-	if (!old)
-		return ERR_PTR(-ENOENT);
-
-	debug_print_probes(entry);
-	/* (N -> M), (N > 1, M >= 0) probes */
-	for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
-		if (!probe ||
-		     (old[nr_probes].func == probe &&
-		     old[nr_probes].data == data))
-			nr_del++;
-	}
-
-	if (nr_probes - nr_del == 0) {
-		/* N -> 0, (N > 1) */
-		entry->probes = NULL;
-		entry->refcount = 0;
-		debug_print_probes(entry);
-		return old;
-	} else {
-		int j = 0;
-		/* N -> M, (N > 1, M > 0) */
-		/* + 1 for NULL */
-		new = allocate_probes(nr_probes - nr_del + 1);
-		if (new == NULL)
-			return ERR_PTR(-ENOMEM);
-		for (i = 0; old[i].func; i++)
-			if (probe &&
-			    (old[i].func != probe || old[i].data != data))
-				new[j++] = old[i];
-		new[nr_probes - nr_del].func = NULL;
-		entry->refcount = nr_probes - nr_del;
-		entry->probes = new;
-	}
-	debug_print_probes(entry);
-	return old;
-}
-
-/*
- * Get tracepoint if the tracepoint is present in the tracepoint hash table.
- * Must be called with tracepoints_mutex held.
- * Returns NULL if not present.
- */
-static struct tracepoint_entry *get_tracepoint(const char *name)
-{
-	struct cds_hlist_head *head;
-	struct cds_hlist_node *node;
-	struct tracepoint_entry *e;
-	uint32_t hash = jhash(name, strlen(name), 0);
-
-	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
-	cds_hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name))
-			return e;
-	}
-	return NULL;
-}
-
-/*
- * Add the tracepoint to the tracepoint hash table. Must be called with
- * tracepoints_mutex held.
- */
-static struct tracepoint_entry *add_tracepoint(const char *name)
-{
-	struct cds_hlist_head *head;
-	struct cds_hlist_node *node;
-	struct tracepoint_entry *e;
-	size_t name_len = strlen(name) + 1;
-	uint32_t hash = jhash(name, name_len-1, 0);
-
-	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
-	cds_hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			DBG("tracepoint %s busy", name);
-			return ERR_PTR(-EEXIST);	/* Already there */
-		}
-	}
-	/*
-	 * Using zmalloc here to allocate a variable length element. Could
-	 * cause some memory fragmentation if overused.
-	 */
-	e = zmalloc(sizeof(struct tracepoint_entry) + name_len);
-	if (!e)
-		return ERR_PTR(-ENOMEM);
-	memcpy(&e->name[0], name, name_len);
-	e->probes = NULL;
-	e->refcount = 0;
-	cds_hlist_add_head(&e->hlist, head);
-	return e;
-}
-
-/*
- * Remove the tracepoint from the tracepoint hash table. Must be called with
- * ust_lock held.
- */
-static inline void remove_tracepoint(struct tracepoint_entry *e)
-{
-	cds_hlist_del(&e->hlist);
-	free(e);
-}
-
-/*
- * Sets the probe callback corresponding to one tracepoint.
- */
-static void set_tracepoint(struct tracepoint_entry **entry,
-	struct tracepoint *elem, int active)
-{
-	WARN_ON(strcmp((*entry)->name, elem->name) != 0);
-
-	/*
-	 * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new
-	 * probe callbacks array is consistent before setting a pointer to it.
-	 * This array is referenced by __DO_TRACE from
-	 * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends()
-	 * is used.
-	 */
-	rcu_assign_pointer(elem->probes, (*entry)->probes);
-	elem->state = active;
-}
-
-/*
- * Disable a tracepoint and its probe callback.
- * Note: only waiting an RCU period after setting elem->call to the empty
- * function insures that the original callback is not used anymore. This insured
- * by preempt_disable around the call site.
- */
-static void disable_tracepoint(struct tracepoint *elem)
-{
-	elem->state = 0;
-	rcu_assign_pointer(elem->probes, NULL);
-}
-
-/**
- * tracepoint_update_probe_range - Update a probe range
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Updates the probe callback corresponding to a range of tracepoints.
- */
-static
-void tracepoint_update_probe_range(struct tracepoint * const *begin,
-				   struct tracepoint * const *end)
-{
-	struct tracepoint * const *iter;
-	struct tracepoint_entry *mark_entry;
-
-	for (iter = begin; iter < end; iter++) {
-		if (!*iter)
-			continue;	/* skip dummy */
-		if (!(*iter)->name) {
-			disable_tracepoint(*iter);
-			continue;
-		}
-		mark_entry = get_tracepoint((*iter)->name);
-		if (mark_entry) {
-			set_tracepoint(&mark_entry, *iter,
-					!!mark_entry->refcount);
-		} else {
-			disable_tracepoint(*iter);
-		}
-	}
-}
-
-static void lib_update_tracepoints(void)
-{
-	struct tracepoint_lib *lib;
-
-	cds_list_for_each_entry(lib, &libs, list) {
-		tracepoint_update_probe_range(lib->tracepoints_start,
-				lib->tracepoints_start + lib->tracepoints_count);
-	}
-}
-
-/*
- * Update probes, removing the faulty probes.
- */
-static void tracepoint_update_probes(void)
-{
-	/* tracepoints registered from libraries and executable. */
-	lib_update_tracepoints();
-}
-
-static struct tracepoint_probe *
-tracepoint_add_probe(const char *name, void *probe, void *data)
-{
-	struct tracepoint_entry *entry;
-	struct tracepoint_probe *old;
-
-	entry = get_tracepoint(name);
-	if (!entry) {
-		entry = add_tracepoint(name);
-		if (IS_ERR(entry))
-			return (struct tracepoint_probe *)entry;
-	}
-	old = tracepoint_entry_add_probe(entry, probe, data);
-	if (IS_ERR(old) && !entry->refcount)
-		remove_tracepoint(entry);
-	return old;
-}
-
-/**
- * __tracepoint_probe_register -  Connect a probe to a tracepoint
- * @name: tracepoint name
- * @probe: probe handler
- *
- * Returns 0 if ok, error value on error.
- * The probe address must at least be aligned on the architecture pointer size.
- * Called with the UST lock held.
- */
-int __tracepoint_probe_register(const char *name, void *probe, void *data)
-{
-	void *old;
-
-	old = tracepoint_add_probe(name, probe, data);
-	if (IS_ERR(old))
-		return PTR_ERR(old);
-
-	tracepoint_update_probes();		/* may update entry */
-	release_probes(old);
-	return 0;
-}
-
-static void *tracepoint_remove_probe(const char *name, void *probe, void *data)
-{
-	struct tracepoint_entry *entry;
-	void *old;
-
-	entry = get_tracepoint(name);
-	if (!entry)
-		return ERR_PTR(-ENOENT);
-	old = tracepoint_entry_remove_probe(entry, probe, data);
-	if (IS_ERR(old))
-		return old;
-	if (!entry->refcount)
-		remove_tracepoint(entry);
-	return old;
-}
-
-/**
- * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
- * @name: tracepoint name
- * @probe: probe function pointer
- * @probe: probe data pointer
- *
- * Called with the UST lock held.
- */
-int __tracepoint_probe_unregister(const char *name, void *probe, void *data)
-{
-	void *old;
-
-	old = tracepoint_remove_probe(name, probe, data);
-	if (IS_ERR(old))
-		return PTR_ERR(old);
-
-	tracepoint_update_probes();		/* may update entry */
-	release_probes(old);
-	return 0;
-}
-
-static void tracepoint_add_old_probes(void *old)
-{
-	need_update = 1;
-	if (old) {
-		struct tp_probes *tp_probes = caa_container_of(old,
-			struct tp_probes, probes[0]);
-		cds_list_add(&tp_probes->u.list, &old_probes);
-	}
-}
-
-/**
- * tracepoint_probe_register_noupdate -  register a probe but not connect
- * @name: tracepoint name
- * @probe: probe handler
- *
- * caller must call tracepoint_probe_update_all()
- * Called with the UST lock held.
- */
-int tracepoint_probe_register_noupdate(const char *name, void *probe,
-				       void *data)
-{
-	void *old;
-
-	old = tracepoint_add_probe(name, probe, data);
-	if (IS_ERR(old)) {
-		return PTR_ERR(old);
-	}
-	tracepoint_add_old_probes(old);
-	return 0;
-}
-
-/**
- * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
- * @name: tracepoint name
- * @probe: probe function pointer
- *
- * caller must call tracepoint_probe_update_all()
- * Called with the UST lock held.
- */
-int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
-					 void *data)
-{
-	void *old;
-
-	old = tracepoint_remove_probe(name, probe, data);
-	if (IS_ERR(old)) {
-		return PTR_ERR(old);
-	}
-	tracepoint_add_old_probes(old);
-	return 0;
-}
-
-/**
- * tracepoint_probe_update_all -  update tracepoints
- * Called with the UST lock held.
- */
-void tracepoint_probe_update_all(void)
-{
-	CDS_LIST_HEAD(release_probes);
-	struct tp_probes *pos, *next;
-
-	if (!need_update) {
-		return;
-	}
-	if (!cds_list_empty(&old_probes))
-		cds_list_replace_init(&old_probes, &release_probes);
-	need_update = 0;
-
-	tracepoint_update_probes();
-	cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
-		cds_list_del(&pos->u.list);
-		synchronize_rcu();
-		free(pos);
-	}
-}
-
-/*
- * Returns 0 if current not found.
- * Returns 1 if current found.
- *
- * Called with tracepoint mutex held
- */
-int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
-{
-	struct tracepoint_lib *iter_lib;
-	int found = 0;
-
-	cds_list_for_each_entry(iter_lib, &libs, list) {
-		if (iter_lib < iter->lib)
-			continue;
-		else if (iter_lib > iter->lib)
-			iter->tracepoint = NULL;
-		found = tracepoint_get_iter_range(&iter->tracepoint,
-			iter_lib->tracepoints_start,
-			iter_lib->tracepoints_start + iter_lib->tracepoints_count);
-		if (found) {
-			iter->lib = iter_lib;
-			break;
-		}
-	}
-	return found;
-}
-
-/**
- * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
- * @tracepoint: current tracepoints (in), next tracepoint (out)
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Returns whether a next tracepoint has been found (1) or not (0).
- * Will return the first tracepoint in the range if the input tracepoint is
- * NULL.
- * Called with tracepoint mutex held.
- */
-int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
-	struct tracepoint * const *begin, struct tracepoint * const *end)
-{
-	if (!*tracepoint && begin != end)
-		*tracepoint = begin;
-	while (*tracepoint >= begin && *tracepoint < end) {
-		if (!**tracepoint)
-			(*tracepoint)++;	/* skip dummy */
-		else
-			return 1;
-	}
-	return 0;
-}
-
-/*
- * Called with tracepoint mutex held.
- */
-static void tracepoint_get_iter(struct tracepoint_iter *iter)
-{
-	int found = 0;
-
-	/* tracepoints in libs. */
-	found = lib_get_iter_tracepoints(iter);
-	if (!found)
-		tracepoint_iter_reset(iter);
-}
-
-/*
- * Called with UST lock held.
- */
-void tracepoint_iter_start(struct tracepoint_iter *iter)
-{
-	tracepoint_get_iter(iter);
-}
-
-/*
- * Called with UST lock held.
- */
-void tracepoint_iter_next(struct tracepoint_iter *iter)
-{
-	iter->tracepoint++;
-	/*
-	 * iter->tracepoint may be invalid because we blindly incremented it.
-	 * Make sure it is valid by marshalling on the tracepoints, getting the
-	 * tracepoints from following modules if necessary.
-	 */
-	tracepoint_get_iter(iter);
-}
-
-/*
- * Called with UST lock held.
- */
-void tracepoint_iter_stop(struct tracepoint_iter *iter)
-{
-}
-
-void tracepoint_iter_reset(struct tracepoint_iter *iter)
-{
-	iter->tracepoint = NULL;
-}
-
-void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
-{
-	new_tracepoint_cb = cb;
-}
-
-static void new_tracepoints(struct tracepoint * const *start, struct tracepoint * const *end)
-{
-	if (new_tracepoint_cb) {
-		struct tracepoint * const *t;
-
-		for (t = start; t < end; t++) {
-			if (*t)
-				new_tracepoint_cb(*t);
-		}
-	}
-}
-
-int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
-			    int tracepoints_count)
-{
-	struct tracepoint_lib *pl, *iter;
-
-	init_tracepoint();
-
-	pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib));
-
-	pl->tracepoints_start = tracepoints_start;
-	pl->tracepoints_count = tracepoints_count;
-
-	ust_lock();
-	/*
-	 * We sort the libs by struct lib pointer address.
-	 */
-	cds_list_for_each_entry_reverse(iter, &libs, list) {
-		BUG_ON(iter == pl);    /* Should never be in the list twice */
-		if (iter < pl) {
-			/* We belong to the location right after iter. */
-			cds_list_add(&pl->list, &iter->list);
-			goto lib_added;
-		}
-	}
-	/* We should be added at the head of the list */
-	cds_list_add(&pl->list, &libs);
-lib_added:
-	new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
-
-	/* TODO: update just the loaded lib */
-	lib_update_tracepoints();
-	ust_unlock();
-
-	DBG("just registered a tracepoints section from %p and having %d tracepoints",
-		tracepoints_start, tracepoints_count);
-
-	return 0;
-}
-
-int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start)
-{
-	struct tracepoint_lib *lib;
-
-	ust_lock();
-	cds_list_for_each_entry(lib, &libs, list) {
-		if (lib->tracepoints_start == tracepoints_start) {
-			struct tracepoint_lib *lib2free = lib;
-			cds_list_del(&lib->list);
-			free(lib2free);
-			break;
-		}
-	}
-	ust_unlock();
-
-	return 0;
-}
-
-void init_tracepoint(void)
-{
-	if (uatomic_xchg(&initialized, 1) == 1)
-		return;
-	init_usterr();
-}
-
-void exit_tracepoint(void)
-{
-	initialized = 0;
-}