1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
3 * lttng-context-mnt-ns.c
5 * LTTng mount 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 <lttng/events.h>
16 #include <lttng/events-internal.h>
17 #include <linux/nsproxy.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(LTTNG_MNT_NS_MISSING_HEADER) && \
24 (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,8,0))
26 #include <../fs/mount.h>
29 size_t mnt_ns_get_size(void *priv
, struct lttng_kernel_probe_ctx
*probe_ctx
, size_t offset
)
33 size
+= lib_ring_buffer_align(offset
, lttng_alignof(unsigned int));
34 size
+= sizeof(unsigned int);
39 void mnt_ns_record(void *priv
, struct lttng_kernel_probe_ctx
*probe_ctx
,
40 struct lttng_kernel_ring_buffer_ctx
*ctx
,
41 struct lttng_kernel_channel_buffer
*chan
)
43 unsigned int mnt_ns_inum
= 0;
46 * nsproxy can be NULL when scheduled out of exit.
48 * As documented in 'linux/nsproxy.h' namespaces access rules, no
49 * precautions should be taken when accessing the current task's
50 * namespaces, just dereference the pointers.
53 mnt_ns_inum
= current
->nsproxy
->mnt_ns
->lttng_ns_inum
;
55 chan
->ops
->event_write(ctx
, &mnt_ns_inum
, sizeof(mnt_ns_inum
), lttng_alignof(mnt_ns_inum
));
59 void mnt_ns_get_value(void *priv
,
60 struct lttng_kernel_probe_ctx
*lttng_probe_ctx
,
61 struct lttng_ctx_value
*value
)
63 unsigned int mnt_ns_inum
= 0;
66 * nsproxy can be NULL when scheduled out of exit.
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.
73 mnt_ns_inum
= current
->nsproxy
->mnt_ns
->lttng_ns_inum
;
75 value
->u
.s64
= mnt_ns_inum
;
78 static const struct lttng_kernel_ctx_field
*ctx_field
= lttng_kernel_static_ctx_field(
79 lttng_kernel_static_event_field("mnt_ns",
80 lttng_kernel_static_type_integer_from_type(unsigned int, __BYTE_ORDER
, 10),
87 int lttng_add_mnt_ns_to_ctx(struct lttng_kernel_ctx
**ctx
)
91 if (lttng_kernel_find_context(*ctx
, ctx_field
->event_field
->name
))
93 ret
= lttng_kernel_context_append(ctx
, ctx_field
);
94 wrapper_vmalloc_sync_mappings();
97 EXPORT_SYMBOL_GPL(lttng_add_mnt_ns_to_ctx
);