| /* |
| * (C) Copyright 2009-2011 - |
| * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| * |
| * LTTng procname context. |
| * |
| * Dual LGPL v2.1/GPL v2 license. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/sched.h> |
| #include "ltt-events.h" |
| #include "wrapper/ringbuffer/frontend_types.h" |
| #include "wrapper/vmalloc.h" |
| #include "ltt-tracer.h" |
| |
| static |
| size_t procname_get_size(size_t offset) |
| { |
| size_t size = 0; |
| |
| size += sizeof(current->comm); |
| return size; |
| } |
| |
| /* |
| * Racy read of procname. We simply copy its whole array size. |
| * Races with /proc/<task>/procname write only. |
| * Otherwise having to take a mutex for each event is cumbersome and |
| * could lead to crash in IRQ context and deadlock of the lockdep tracer. |
| */ |
| static |
| void procname_record(struct lttng_ctx_field *field, |
| struct lib_ring_buffer_ctx *ctx, |
| struct ltt_channel *chan) |
| { |
| chan->ops->event_write(ctx, current->comm, sizeof(current->comm)); |
| } |
| |
| int lttng_add_procname_to_ctx(struct lttng_ctx **ctx) |
| { |
| struct lttng_ctx_field *field; |
| |
| field = lttng_append_context(ctx); |
| if (!field) |
| return -ENOMEM; |
| if (lttng_find_context(*ctx, "procname")) { |
| lttng_remove_context_field(ctx, field); |
| return -EEXIST; |
| } |
| field->event_field.name = "procname"; |
| field->event_field.type.atype = atype_array; |
| field->event_field.type.u.array.elem_type.atype = atype_integer; |
| field->event_field.type.u.array.elem_type.u.basic.integer.size = sizeof(char) * CHAR_BIT; |
| field->event_field.type.u.array.elem_type.u.basic.integer.alignment = ltt_alignof(char) * CHAR_BIT; |
| field->event_field.type.u.array.elem_type.u.basic.integer.signedness = is_signed_type(char); |
| field->event_field.type.u.array.elem_type.u.basic.integer.reverse_byte_order = 0; |
| field->event_field.type.u.array.elem_type.u.basic.integer.base = 10; |
| field->event_field.type.u.array.elem_type.u.basic.integer.encoding = lttng_encode_UTF8; |
| field->event_field.type.u.array.length = sizeof(current->comm); |
| |
| field->get_size = procname_get_size; |
| field->record = procname_record; |
| wrapper_vmalloc_sync_all(); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(lttng_add_procname_to_ctx); |
| |
| MODULE_LICENSE("GPL and additional rights"); |
| MODULE_AUTHOR("Mathieu Desnoyers"); |
| MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support"); |