1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
3 * lttng-context-cgroup-ns.c
5 * LTTng cgroup namespace context.
7 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * 2019 Michael Jeanson <mjeanson@efficios.com>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/cgroup.h>
16 #include <lttng/events.h>
17 #include <lttng/events-internal.h>
18 #include <ringbuffer/frontend_types.h>
19 #include <wrapper/vmalloc.h>
20 #include <wrapper/namespace.h>
21 #include <lttng/tracer.h>
23 #if defined(CONFIG_CGROUPS) && \
24 ((LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0)) || \
25 LTTNG_UBUNTU_KERNEL_RANGE(4,4,0,0, 4,5,0,0))
28 size_t cgroup_ns_get_size(void *priv
, struct lttng_kernel_probe_ctx
*probe_ctx
, size_t offset
)
32 size
+= lib_ring_buffer_align(offset
, lttng_alignof(unsigned int));
33 size
+= sizeof(unsigned int);
38 void cgroup_ns_record(void *priv
, struct lttng_kernel_probe_ctx
*probe_ctx
,
39 struct lttng_kernel_ring_buffer_ctx
*ctx
,
40 struct lttng_kernel_channel_buffer
*chan
)
42 unsigned int cgroup_ns_inum
= 0;
45 * nsproxy can be NULL when scheduled out of exit.
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.
52 cgroup_ns_inum
= current
->nsproxy
->cgroup_ns
->lttng_ns_inum
;
54 chan
->ops
->event_write(ctx
, &cgroup_ns_inum
, sizeof(cgroup_ns_inum
), lttng_alignof(cgroup_ns_inum
));
58 void cgroup_ns_get_value(void *priv
,
59 struct lttng_kernel_probe_ctx
*lttng_probe_ctx
,
60 struct lttng_ctx_value
*value
)
62 unsigned int cgroup_ns_inum
= 0;
65 * nsproxy can be NULL when scheduled out of exit.
67 * As documented in 'linux/nsproxy.h' namespaces access rules, no
68 * precautions should be taken when accessing the current task's
69 * namespaces, just dereference the pointers.
72 cgroup_ns_inum
= current
->nsproxy
->cgroup_ns
->lttng_ns_inum
;
74 value
->u
.s64
= cgroup_ns_inum
;
77 static const struct lttng_kernel_ctx_field
*ctx_field
= lttng_kernel_static_ctx_field(
78 lttng_kernel_static_event_field("cgroup_ns",
79 lttng_kernel_static_type_integer_from_type(unsigned int, __BYTE_ORDER
, 10),
86 int lttng_add_cgroup_ns_to_ctx(struct lttng_kernel_ctx
**ctx
)
90 if (lttng_kernel_find_context(*ctx
, ctx_field
->event_field
->name
))
92 ret
= lttng_kernel_context_append(ctx
, ctx_field
);
93 wrapper_vmalloc_sync_mappings();
96 EXPORT_SYMBOL_GPL(lttng_add_cgroup_ns_to_ctx
);