+++ /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 <linux/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/tracer.h>
-#include <wrapper/irqflags.h>
-#include <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_uprobe_handler *uprobe_handler =
- container_of(uc, struct lttng_uprobe_handler, up_consumer);
- struct lttng_event *event = uprobe_handler->event;
- 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(!READ_ONCE(chan->session->active)))
- return 0;
- if (unlikely(!READ_ONCE(chan->enabled)))
- return 0;
- if (unlikely(!READ_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 = (unsigned long)instruction_pointer(regs);
-
- 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.integer.size = sizeof(unsigned long) * CHAR_BIT;
- fields[0].type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
- fields[0].type.u.integer.signedness = lttng_is_signed_type(unsigned long);
- fields[0].type.u.integer.reverse_byte_order = 0;
- fields[0].type.u.integer.base = 16;
- fields[0].type.u.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;
-}
-
-/*
- * 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 = fcheck(fd);
- if (file == NULL) {
- printk(KERN_WARNING "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 "Cannot grab a reference on the inode.\n");
-error:
- rcu_read_unlock();
- return inode;
-}
-
-int lttng_uprobes_add_callsite(struct lttng_event *event,
- struct lttng_kernel_event_callsite __user *callsite)
-{
- int ret = 0;
- struct lttng_uprobe_handler *uprobe_handler;
-
- if (!event) {
- ret = -EINVAL;
- goto end;
- }
-
- uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL);
- if (!uprobe_handler) {
- printk(KERN_WARNING "Error allocating uprobe_uprobe_handlers");
- ret = -ENOMEM;
- goto end;
- }
-
- /* Ensure the memory we just allocated don't trigger page faults. */
- wrapper_vmalloc_sync_mappings();
-
- uprobe_handler->event = event;
- uprobe_handler->up_consumer.handler = lttng_uprobes_handler_pre;
-
- ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t));
- if (ret) {
- goto register_error;
- }
-
- ret = wrapper_uprobe_register(event->u.uprobe.inode,
- uprobe_handler->offset, &uprobe_handler->up_consumer);
- if (ret) {
- printk(KERN_WARNING "Error registering probe on inode %lu "
- "and offset 0x%llx\n", event->u.uprobe.inode->i_ino,
- uprobe_handler->offset);
- ret = -1;
- goto register_error;
- }
-
- list_add(&uprobe_handler->node, &event->u.uprobe.head);
-
- return ret;
-
-register_error:
- kfree(uprobe_handler);
-end:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_uprobes_add_callsite);
-
-int lttng_uprobes_register(const char *name, int fd, struct lttng_event *event)
-{
- int ret = 0;
- struct inode *inode;
-
- ret = lttng_create_uprobe_event(name, event);
- if (ret)
- goto error;
-
- inode = get_inode_from_fd(fd);
- if (!inode) {
- printk(KERN_WARNING "Cannot get inode from fd\n");
- ret = -EBADF;
- goto inode_error;
- }
- event->u.uprobe.inode = inode;
- INIT_LIST_HEAD(&event->u.uprobe.head);
-
- return 0;
-
-inode_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)
-{
- 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, &event->u.uprobe.head, node) {
- wrapper_uprobe_unregister(event->u.uprobe.inode, iter->offset,
- &iter->up_consumer);
- list_del(&iter->node);
- kfree(iter);
- }
-}
-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