X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=probes%2Flttng-uprobes.c;h=175c0dd9d5993ddcfb63865a6971715b6f94e504;hb=ceabb767180e064629b5a9ab4ed14449da864763;hp=0906992022897fca346e9ab937e51b8b2163c87a;hpb=149b9a9d86d7351ee9a44ce391884cc12e922124;p=lttng-modules.git diff --git a/probes/lttng-uprobes.c b/probes/lttng-uprobes.c index 09069920..175c0dd9 100644 --- a/probes/lttng-uprobes.c +++ b/probes/lttng-uprobes.c @@ -1,4 +1,5 @@ -/* +/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) + * * probes/lttng-uprobes.c * * LTTng uprobes integration module. @@ -6,25 +7,14 @@ * Copyright (C) 2013 Yannick Brosseau * Copyright (C) 2009-2012 Mathieu Desnoyers * - * 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 +#include #include #include #include +#include #include #include #include @@ -35,8 +25,9 @@ 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_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), @@ -47,13 +38,13 @@ int lttng_uprobes_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) struct { unsigned long ip; - } payload; + } payload; - if (unlikely(!ACCESS_ONCE(chan->session->active))) + if (unlikely(!READ_ONCE(chan->session->active))) return 0; - if (unlikely(!ACCESS_ONCE(chan->enabled))) + if (unlikely(!READ_ONCE(chan->enabled))) return 0; - if (unlikely(!ACCESS_ONCE(event->enabled))) + if (unlikely(!READ_ONCE(event->enabled))) return 0; lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, @@ -64,7 +55,8 @@ int lttng_uprobes_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) return 0; /* Event payload. */ - payload.ip = regs->ip; + 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); @@ -100,12 +92,12 @@ int lttng_create_uprobe_event(const char *name, struct lttng_event *event) } 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; + 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; @@ -119,52 +111,108 @@ error_str: return ret; } -int lttng_uprobes_register(const char *name, - const char *path_name, - uint64_t offset, - struct lttng_event *event) +/* + * 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) { - 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) + 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; + } - memset(&event->u.uprobe.up_consumer, 0, - sizeof(event->u.uprobe.up_consumer)); + /* 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; +} - 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; +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; - event->u.uprobe.inode = igrab(path.dentry->d_inode); + if (!event) { + ret = -EINVAL; + goto end; } - event->u.uprobe.offset = offset; - /* Ensure the memory we just allocated don't trigger page faults. */ + 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_all(); - printk(KERN_WARNING "Registering probe on inode %lu and offset %llu\n", event->u.uprobe.inode->i_ino, event->u.uprobe.offset); + + 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, - event->u.uprobe.offset, - &event->u.uprobe.up_consumer); + uprobe_handler->offset, &uprobe_handler->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); + "and offset 0x%llx\n", event->u.uprobe.inode->i_ino, + uprobe_handler->offset); + ret = -1; goto register_error; } - return 0; + + list_add(&uprobe_handler->node, &event->u.uprobe.head); + + return ret; register_error: - iput(event->u.uprobe.inode); -path_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: @@ -174,9 +222,18 @@ 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); + 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);