+++ /dev/null
-/*
- * probes/lttng-uprobes.c
- *
- * LTTng uprobes integration module.
- *
- * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
- * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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; only
- * 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
- */
-
-#include <linux/fdtable.h>
-#include <linux/module.h>
-#include <linux/namei.h>
-#include <linux/slab.h>
-#include <lttng-events.h>
-#include <lttng-tracer.h>
-#include <wrapper/irqflags.h>
-#include <wrapper/ringbuffer/frontend_types.h>
-#include <wrapper/uprobes.h>
-#include <wrapper/vmalloc.h>
-
-static
-int lttng_uprobes_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs)
-{
- struct lttng_event *event =
- container_of(uc, struct lttng_event, u.uprobe.up_consumer);
- struct lttng_probe_ctx lttng_probe_ctx = {
- .event = event,
- .interruptible = !lttng_regs_irqs_disabled(regs),
- };
- struct lttng_channel *chan = event->chan;
- struct lib_ring_buffer_ctx ctx;
- int ret;
-
- struct {
- unsigned long ip;
- } payload;
-
- if (unlikely(!ACCESS_ONCE(chan->session->active)))
- return 0;
- if (unlikely(!ACCESS_ONCE(chan->enabled)))
- return 0;
- if (unlikely(!ACCESS_ONCE(event->enabled)))
- return 0;
-
- lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx,
- sizeof(payload), lttng_alignof(payload), -1);
-
- ret = chan->ops->event_reserve(&ctx, event->id);
- if (ret < 0)
- return 0;
-
- /* Event payload. */
- payload.ip = regs->ip;
- lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
- chan->ops->event_write(&ctx, &payload, sizeof(payload));
- chan->ops->event_commit(&ctx);
- return 0;
-}
-
-/*
- * Create event description.
- */
-static
-int lttng_create_uprobe_event(const char *name, struct lttng_event *event)
-{
- struct lttng_event_desc *desc;
- struct lttng_event_field *fields;
- int ret;
-
- desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
- if (!desc)
- return -ENOMEM;
- desc->name = kstrdup(name, GFP_KERNEL);
- if (!desc->name) {
- ret = -ENOMEM;
- goto error_str;
- }
-
- desc->nr_fields = 1;
- desc->fields = fields =
- kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
-
- if (!desc->fields) {
- ret = -ENOMEM;
- goto error_fields;
- }
- fields[0].name = "ip";
- fields[0].type.atype = atype_integer;
- fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
- fields[0].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
- fields[0].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
- fields[0].type.u.basic.integer.reverse_byte_order = 0;
- fields[0].type.u.basic.integer.base = 16;
- fields[0].type.u.basic.integer.encoding = lttng_encode_none;
-
- desc->owner = THIS_MODULE;
- event->desc = desc;
-
- return 0;
-
-error_fields:
- kfree(desc->name);
-error_str:
- kfree(desc);
- return ret;
-}
-
-int lttng_uprobes_register(const char *name,
- const char *path_name,
- uint64_t offset,
- struct lttng_event *event)
-{
- int ret;
-
- /* Shoudl we fail if the path is empty, it should be checked before */
- if (path_name[0] == '\0')
- path_name = NULL;
-
- ret = lttng_create_uprobe_event(name, event);
- if (ret)
- goto error;
-
- memset(&event->u.uprobe.up_consumer, 0,
- sizeof(event->u.uprobe.up_consumer));
-
- event->u.uprobe.up_consumer.handler = lttng_uprobes_handler_pre;
- if (path_name) {
- struct path path;
- ret = kern_path(path_name, LOOKUP_FOLLOW, &path);
- if (ret)
- goto path_error;
-
- event->u.uprobe.inode = igrab(path.dentry->d_inode);
- }
- event->u.uprobe.offset = offset;
-
- /* Ensure the memory we just allocated don't trigger page faults. */
- wrapper_vmalloc_sync_all();
- printk(KERN_WARNING "Registering probe on inode %lu and offset %llu\n", event->u.uprobe.inode->i_ino, event->u.uprobe.offset);
- ret = wrapper_uprobe_register(event->u.uprobe.inode,
- event->u.uprobe.offset,
- &event->u.uprobe.up_consumer);
- if (ret) {
- printk(KERN_WARNING "Error registering probe on inode %lu "
- "and offset %llu\n", event->u.uprobe.inode->i_ino,
- event->u.uprobe.offset);
- goto register_error;
- }
- return 0;
-
-register_error:
- iput(event->u.uprobe.inode);
-path_error:
- kfree(event->desc->name);
- kfree(event->desc);
-error:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_register);
-
-void lttng_uprobes_unregister(struct lttng_event *event)
-{
- wrapper_uprobe_unregister(event->u.uprobe.inode,
- event->u.uprobe.offset,
- &event->u.uprobe.up_consumer);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_unregister);
-
-void lttng_uprobes_destroy_private(struct lttng_event *event)
-{
- iput(event->u.uprobe.inode);
- kfree(event->desc->name);
- kfree(event->desc);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_private);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Yannick Brosseau");
-MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support");
projects / lttng-modules.git / blobdiff