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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
a6cf40a4 MJ |
2 | * |
3 | * lttng-context-cgroup-ns.c | |
4 | * | |
5 | * LTTng cgroup namespace context. | |
6 | * | |
7 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * 2019 Michael Jeanson <mjeanson@efficios.com> | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/cgroup.h> | |
2df37e95 | 16 | #include <lttng/events.h> |
437d5aa5 | 17 | #include <lttng/events-internal.h> |
24591303 | 18 | #include <ringbuffer/frontend_types.h> |
a6cf40a4 MJ |
19 | #include <wrapper/vmalloc.h> |
20 | #include <wrapper/namespace.h> | |
2df37e95 | 21 | #include <lttng/tracer.h> |
a6cf40a4 MJ |
22 | |
23 | #if defined(CONFIG_CGROUPS) && \ | |
5f4c791e | 24 | ((LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0)) || \ |
a6cf40a4 MJ |
25 | LTTNG_UBUNTU_KERNEL_RANGE(4,4,0,0, 4,5,0,0)) |
26 | ||
27 | static | |
28 | size_t cgroup_ns_get_size(size_t offset) | |
29 | { | |
30 | size_t size = 0; | |
31 | ||
32 | size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); | |
33 | size += sizeof(unsigned int); | |
34 | return size; | |
35 | } | |
36 | ||
37 | static | |
437d5aa5 | 38 | void cgroup_ns_record(struct lttng_kernel_ctx_field *field, |
a6cf40a4 MJ |
39 | struct lib_ring_buffer_ctx *ctx, |
40 | struct lttng_channel *chan) | |
41 | { | |
42 | unsigned int cgroup_ns_inum = 0; | |
43 | ||
44 | /* | |
45 | * nsproxy can be NULL when scheduled out of exit. | |
46 | * | |
47 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
48 | * precautions should be taken when accessing the current task's | |
49 | * namespaces, just dereference the pointers. | |
50 | */ | |
51 | if (current->nsproxy) | |
52 | cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum; | |
53 | ||
54 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(cgroup_ns_inum)); | |
55 | chan->ops->event_write(ctx, &cgroup_ns_inum, sizeof(cgroup_ns_inum)); | |
56 | } | |
57 | ||
58 | static | |
437d5aa5 | 59 | void cgroup_ns_get_value(struct lttng_kernel_ctx_field *field, |
a6cf40a4 MJ |
60 | struct lttng_probe_ctx *lttng_probe_ctx, |
61 | union lttng_ctx_value *value) | |
62 | { | |
63 | unsigned int cgroup_ns_inum = 0; | |
64 | ||
65 | /* | |
66 | * nsproxy can be NULL when scheduled out of exit. | |
67 | * | |
68 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
69 | * precautions should be taken when accessing the current task's | |
70 | * namespaces, just dereference the pointers. | |
71 | */ | |
72 | if (current->nsproxy) | |
73 | cgroup_ns_inum = current->nsproxy->cgroup_ns->lttng_ns_inum; | |
74 | ||
75 | value->s64 = cgroup_ns_inum; | |
76 | } | |
77 | ||
437d5aa5 MD |
78 | static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field( |
79 | lttng_kernel_static_event_field("cgroup_ns", | |
80 | lttng_kernel_static_type_integer_from_type(unsigned int, __BYTE_ORDER, 10), | |
81 | false, false, false), | |
82 | cgroup_ns_get_size, | |
83 | NULL, | |
84 | cgroup_ns_record, | |
85 | cgroup_ns_get_value, | |
86 | NULL, NULL); | |
87 | ||
88 | int lttng_add_cgroup_ns_to_ctx(struct lttng_kernel_ctx **ctx) | |
a6cf40a4 | 89 | { |
437d5aa5 | 90 | int ret; |
a6cf40a4 | 91 | |
437d5aa5 | 92 | if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name)) |
a6cf40a4 | 93 | return -EEXIST; |
437d5aa5 | 94 | ret = lttng_kernel_context_append(ctx, ctx_field); |
263b6c88 | 95 | wrapper_vmalloc_sync_mappings(); |
437d5aa5 | 96 | return ret; |
a6cf40a4 MJ |
97 | } |
98 | EXPORT_SYMBOL_GPL(lttng_add_cgroup_ns_to_ctx); | |
99 | ||
100 | #endif |