projects / lttng-modules.git / blame
| Commit | Line | Data |
|---|---|---|
| b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
| 9f36eaed | 2 | * |
| 886d51a3 | 3 | * lttng-context-ppid.c |
| b64bc438 MD |
4 | * |
| 5 | * LTTng PPID context. | |
| 6 | * | |
| 886d51a3 | 7 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| b64bc438 MD |
8 | */ |
| 9 | ||
| 10 | #include <linux/module.h> | |
| 11 | #include <linux/slab.h> | |
| 12 | #include <linux/sched.h> | |
| 13 | #include <linux/syscalls.h> | |
| 2df37e95 | 14 | #include <lttng/events.h> |
| 437d5aa5 | 15 | #include <lttng/events-internal.h> |
| 24591303 | 16 | #include <ringbuffer/frontend_types.h> |
| 241ae9a8 | 17 | #include <wrapper/vmalloc.h> |
| 2df37e95 | 18 | #include <lttng/tracer.h> |
| b64bc438 MD |
19 | |
| 20 | static | |
| 21 | size_t ppid_get_size(size_t offset) | |
| 22 | { | |
| 23 | size_t size = 0; | |
| 24 | ||
| a90917c3 | 25 | size += lib_ring_buffer_align(offset, lttng_alignof(pid_t)); |
| b64bc438 MD |
26 | size += sizeof(pid_t); |
| 27 | return size; | |
| 28 | } | |
| 29 | ||
| 30 | static | |
| 437d5aa5 | 31 | void ppid_record(struct lttng_kernel_ctx_field *field, |
| b64bc438 | 32 | struct lib_ring_buffer_ctx *ctx, |
| a90917c3 | 33 | struct lttng_channel *chan) |
| b64bc438 MD |
34 | { |
| 35 | pid_t ppid; | |
| 36 | ||
| 1638c9b4 MD |
37 | /* |
| 38 | * TODO: when we eventually add RCU subsystem instrumentation, | |
| 39 | * taking the rcu read lock here will trigger RCU tracing | |
| 40 | * recursively. We should modify the kernel synchronization so | |
| 41 | * it synchronizes both for RCU and RCU sched, and rely on | |
| 42 | * rcu_read_lock_sched_notrace. | |
| 43 | */ | |
| b64bc438 MD |
44 | rcu_read_lock(); |
| 45 | ppid = task_tgid_nr(current->real_parent); | |
| 46 | rcu_read_unlock(); | |
| a90917c3 | 47 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid)); |
| b64bc438 MD |
48 | chan->ops->event_write(ctx, &ppid, sizeof(ppid)); |
| 49 | } | |
| 50 | ||
| f127e61e | 51 | static |
| 437d5aa5 | 52 | void ppid_get_value(struct lttng_kernel_ctx_field *field, |
| 79150a49 | 53 | struct lttng_probe_ctx *lttng_probe_ctx, |
| f127e61e MD |
54 | union lttng_ctx_value *value) |
| 55 | { | |
| 56 | pid_t ppid; | |
| 57 | ||
| 58 | /* | |
| 59 | * TODO: when we eventually add RCU subsystem instrumentation, | |
| 60 | * taking the rcu read lock here will trigger RCU tracing | |
| 61 | * recursively. We should modify the kernel synchronization so | |
| 62 | * it synchronizes both for RCU and RCU sched, and rely on | |
| 63 | * rcu_read_lock_sched_notrace. | |
| 64 | */ | |
| 65 | rcu_read_lock(); | |
| 66 | ppid = task_tgid_nr(current->real_parent); | |
| 67 | rcu_read_unlock(); | |
| 68 | value->s64 = ppid; | |
| 69 | } | |
| 70 | ||
| 437d5aa5 MD |
71 | static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field( |
| 72 | lttng_kernel_static_event_field("ppid", | |
| 73 | lttng_kernel_static_type_integer_from_type(pid_t, __BYTE_ORDER, 10), | |
| 74 | false, false, false), | |
| 75 | ppid_get_size, | |
| 76 | NULL, | |
| 77 | ppid_record, | |
| 78 | ppid_get_value, | |
| 79 | NULL, NULL); | |
| 80 | ||
| 81 | int lttng_add_ppid_to_ctx(struct lttng_kernel_ctx **ctx) | |
| b64bc438 | 82 | { |
| 437d5aa5 | 83 | int ret; |
| b64bc438 | 84 | |
| 437d5aa5 | 85 | if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name)) |
| 44252f0f | 86 | return -EEXIST; |
| 437d5aa5 | 87 | ret = lttng_kernel_context_append(ctx, ctx_field); |
| 263b6c88 | 88 | wrapper_vmalloc_sync_mappings(); |
| 437d5aa5 | 89 | return ret; |
| b64bc438 MD |
90 | } |
| 91 | EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx); |