+++ /dev/null
-/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
- *
- * 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>
- *
- */
-
-#include <wrapper/fdtable.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/namei.h>
-#include <linux/slab.h>
-#include <linux/uaccess.h>
-#include <lttng/events.h>
-#include <lttng/events-internal.h>
-#include <lttng/tracer.h>
-#include <wrapper/irqflags.h>
-#include <ringbuffer/frontend_types.h>
-#include <wrapper/uprobes.h>
-#include <wrapper/vmalloc.h>
-
-static
-int lttng_uprobes_event_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs)
-{
- struct lttng_uprobe_handler *uprobe_handler =
- container_of(uc, struct lttng_uprobe_handler, up_consumer);
- struct lttng_kernel_event_common *event = uprobe_handler->event;
- struct lttng_kernel_probe_ctx lttng_probe_ctx = {
- .event = event,
- .interruptible = !lttng_regs_irqs_disabled(regs),
- };
- struct {
- unsigned long ip;
- } payload;
-
- switch (event->type) {
- case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
- {
- struct lttng_kernel_event_recorder *event_recorder =
- container_of(event, struct lttng_kernel_event_recorder, parent);
- struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
-
- if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active)))
- return 0;
- if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled)))
- return 0;
- break;
- }
- case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
- break;
- default:
- WARN_ON_ONCE(1);
- }
-
- if (unlikely(!LTTNG_READ_ONCE(event->enabled)))
- return 0;
-
- switch (event->type) {
- case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
- {
- struct lttng_kernel_event_recorder *event_recorder =
- container_of(event, struct lttng_kernel_event_recorder, parent);
- struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
- struct lttng_kernel_ring_buffer_ctx ctx;
- int ret;
-
- lib_ring_buffer_ctx_init(&ctx, event_recorder,
- sizeof(payload), lttng_alignof(payload), <tng_probe_ctx);
-
- ret = chan->ops->event_reserve(&ctx);
- if (ret < 0)
- return 0;
-
- /* Event payload. */
- payload.ip = (unsigned long)instruction_pointer(regs);
-
- chan->ops->event_write(&ctx, &payload, sizeof(payload), lttng_alignof(payload));
- chan->ops->event_commit(&ctx);
- break;
- }
- case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
- {
- struct lttng_kernel_event_notifier *event_notifier =
- container_of(event, struct lttng_kernel_event_notifier, parent);
- struct lttng_kernel_notification_ctx notif_ctx;
-
- notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture);
- event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx);
- break;
- }
- default:
- WARN_ON_ONCE(1);
- }
- return 0;
-}
-
-static const struct lttng_kernel_event_field *event_fields[] = {
- lttng_kernel_static_event_field("ip",
- lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16),
- false, false, false),
-};
-
-static const struct lttng_kernel_tracepoint_class tp_class = {
- .nr_fields = ARRAY_SIZE(event_fields),
- .fields = event_fields,
-};
-
-/*
- * Create event description.
- */
-static
-int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder)
-{
- struct lttng_kernel_event_desc *desc;
- int ret;
-
- desc = kzalloc(sizeof(*desc), GFP_KERNEL);
- if (!desc)
- return -ENOMEM;
- desc->tp_class = &tp_class;
- desc->event_name = kstrdup(name, GFP_KERNEL);
- if (!desc->event_name) {
- ret = -ENOMEM;
- goto error_str;
- }
- desc->owner = THIS_MODULE;
- event_recorder->priv->parent.desc = desc;
-
- return 0;
-
-error_str:
- kfree(desc);
- return ret;
-}
-
-/*
- * Create event_notifier description.
- */
-static
-int lttng_create_uprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier)
-{
- struct lttng_kernel_event_desc *desc;
- int ret;
-
- desc = kzalloc(sizeof(*desc), GFP_KERNEL);
- if (!desc)
- return -ENOMEM;
- desc->tp_class = &tp_class;
- desc->event_name = kstrdup(name, GFP_KERNEL);
- if (!desc->event_name) {
- ret = -ENOMEM;
- goto error_str;
- }
- desc->owner = THIS_MODULE;
- event_notifier->priv->parent.desc = desc;
-
- return 0;
-
-error_str:
- kfree(desc);
- return ret;
-}
-
-/*
- * Returns the inode struct from the current task and an fd. The inode is
- * grabbed by this function and must be put once we are done with it using
- * iput().
- */
-static struct inode *get_inode_from_fd(int fd)
-{
- struct file *file;
- struct inode *inode;
-
- rcu_read_lock();
- /*
- * Returns the file backing the given fd. Needs to be done inside an RCU
- * critical section.
- */
- file = lttng_lookup_fd_rcu(fd);
- if (file == NULL) {
- printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd);
- inode = NULL;
- goto error;
- }
-
- /* Grab a reference on the inode. */
- inode = igrab(file->f_path.dentry->d_inode);
- if (inode == NULL)
- printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n");
-error:
- rcu_read_unlock();
- return inode;
-}
-
-
-static
-int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe,
- struct lttng_kernel_abi_event_callsite __user *callsite,
- int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs),
- void *priv_data)
-{
- int ret = 0;
- struct lttng_uprobe_handler *uprobe_handler;
-
- if (!priv_data) {
- ret = -EINVAL;
- goto end;
- }
-
- uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL);
- if (!uprobe_handler) {
- printk(KERN_WARNING "LTTng: Error allocating uprobe_handler");
- ret = -ENOMEM;
- goto end;
- }
-
- /* Ensure the memory we just allocated don't notify page faults. */
- wrapper_vmalloc_sync_mappings();
-
- uprobe_handler->event = priv_data;
- uprobe_handler->up_consumer.handler = handler;
-
- ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t));
- if (ret) {
- goto register_error;
- }
-
- ret = wrapper_uprobe_register(uprobe->inode,
- uprobe_handler->offset, &uprobe_handler->up_consumer);
- if (ret) {
- printk(KERN_WARNING "LTTng: Error registering probe on inode %lu "
- "and offset 0x%llx\n", uprobe->inode->i_ino,
- uprobe_handler->offset);
- ret = -1;
- goto register_error;
- }
-
- list_add(&uprobe_handler->node, &uprobe->head);
-
- return ret;
-
-register_error:
- kfree(uprobe_handler);
-end:
- return ret;
-}
-
-int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event,
- struct lttng_kernel_abi_event_callsite __user *callsite)
-{
- return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite,
- lttng_uprobes_event_handler_pre, event);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite);
-
-static
-int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd)
-{
- int ret = 0;
- struct inode *inode;
-
- inode = get_inode_from_fd(fd);
- if (!inode) {
- printk(KERN_WARNING "LTTng: Cannot get inode from fd\n");
- ret = -EBADF;
- goto inode_error;
- }
- uprobe->inode = inode;
- INIT_LIST_HEAD(&uprobe->head);
-
-inode_error:
- return ret;
-}
-
-int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_recorder *event_recorder)
-{
- int ret = 0;
-
- ret = lttng_create_uprobe_event(name, event_recorder);
- if (ret)
- goto error;
-
- ret = lttng_uprobes_register(&event_recorder->priv->parent.u.uprobe, fd);
- if (ret)
- goto register_error;
-
- return 0;
-
-register_error:
- kfree(event_recorder->priv->parent.desc->event_name);
- kfree(event_recorder->priv->parent.desc);
-error:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_register_event);
-
-int lttng_uprobes_register_event_notifier(const char *name, int fd,
- struct lttng_kernel_event_notifier *event_notifier)
-{
- int ret = 0;
-
- ret = lttng_create_uprobe_event_notifier(name, event_notifier);
- if (ret)
- goto error;
-
- ret = lttng_uprobes_register(&event_notifier->priv->parent.u.uprobe, fd);
- if (ret)
- goto register_error;
-
- return 0;
-
-register_error:
- kfree(event_notifier->priv->parent.desc->event_name);
- kfree(event_notifier->priv->parent.desc);
-error:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_register_event_notifier);
-
-static
-void lttng_uprobes_unregister(struct inode *inode, struct list_head *head)
-{
- struct lttng_uprobe_handler *iter, *tmp;
-
- /*
- * Iterate over the list of handler, remove each handler from the list
- * and free the struct.
- */
- list_for_each_entry_safe(iter, tmp, head, node) {
- wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer);
- list_del(&iter->node);
- kfree(iter);
- }
-}
-
-void lttng_uprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder)
-{
- lttng_uprobes_unregister(event_recorder->priv->parent.u.uprobe.inode, &event_recorder->priv->parent.u.uprobe.head);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event);
-
-void lttng_uprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier)
-{
- lttng_uprobes_unregister(event_notifier->priv->parent.u.uprobe.inode, &event_notifier->priv->parent.u.uprobe.head);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event_notifier);
-
-void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder)
-{
- iput(event_recorder->priv->parent.u.uprobe.inode);
- kfree(event_recorder->priv->parent.desc->event_name);
- kfree(event_recorder->priv->parent.desc);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private);
-
-void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier)
-{
- iput(event_notifier->priv->parent.u.uprobe.inode);
- kfree(event_notifier->priv->parent.desc->event_name);
- kfree(event_notifier->priv->parent.desc);
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Yannick Brosseau");
-MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support");
projects / lttng-modules.git / blobdiff