1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
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 <linux/nsproxy.h>
17 #include <wrapper/ringbuffer/frontend_types.h>
18 #include <wrapper/vmalloc.h>
19 #include <wrapper/namespace.h>
20 #include <lttng-tracer.h>
22 #if !defined(LTTNG_MNT_NS_MISSING_HEADER) && \
23 (LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0))
25 #include <../fs/mount.h>
28 size_t mnt_ns_get_size(size_t offset
)
32 size
+= lib_ring_buffer_align(offset
, lttng_alignof(unsigned int));
33 size
+= sizeof(unsigned int);
38 void mnt_ns_record(struct lttng_ctx_field
*field
,
39 struct lib_ring_buffer_ctx
*ctx
,
40 struct lttng_channel
*chan
)
42 unsigned int mnt_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 mnt_ns_inum
= current
->nsproxy
->mnt_ns
->lttng_ns_inum
;
54 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(mnt_ns_inum
));
55 chan
->ops
->event_write(ctx
, &mnt_ns_inum
, sizeof(mnt_ns_inum
));
59 void mnt_ns_get_value(struct lttng_ctx_field
*field
,
60 struct lttng_probe_ctx
*lttng_probe_ctx
,
61 union 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
->s64
= mnt_ns_inum
;
78 int lttng_add_mnt_ns_to_ctx(struct lttng_ctx
**ctx
)
80 struct lttng_ctx_field
*field
;
82 field
= lttng_append_context(ctx
);
85 if (lttng_find_context(*ctx
, "mnt_ns")) {
86 lttng_remove_context_field(ctx
, field
);
89 field
->event_field
.name
= "mnt_ns";
90 field
->event_field
.type
.atype
= atype_integer
;
91 field
->event_field
.type
.u
.basic
.integer
.size
= sizeof(unsigned int) * CHAR_BIT
;
92 field
->event_field
.type
.u
.basic
.integer
.alignment
= lttng_alignof(unsigned int) * CHAR_BIT
;
93 field
->event_field
.type
.u
.basic
.integer
.signedness
= lttng_is_signed_type(unsigned int);
94 field
->event_field
.type
.u
.basic
.integer
.reverse_byte_order
= 0;
95 field
->event_field
.type
.u
.basic
.integer
.base
= 10;
96 field
->event_field
.type
.u
.basic
.integer
.encoding
= lttng_encode_none
;
97 field
->get_size
= mnt_ns_get_size
;
98 field
->record
= mnt_ns_record
;
99 field
->get_value
= mnt_ns_get_value
;
100 lttng_context_update(*ctx
);
101 wrapper_vmalloc_sync_all();
104 EXPORT_SYMBOL_GPL(lttng_add_mnt_ns_to_ctx
);
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