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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
a6cf40a4 MJ |
2 | * |
3 | * lttng-context-uts-ns.c | |
4 | * | |
5 | * LTTng uts 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/utsname.h> | |
16 | #include <lttng-events.h> | |
17 | #include <wrapper/ringbuffer/frontend_types.h> | |
a6cf40a4 MJ |
18 | #include <lttng-tracer.h> |
19 | ||
20 | #if defined(CONFIG_UTS_NS) && \ | |
21 | (LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0)) | |
22 | ||
23 | static | |
24 | size_t uts_ns_get_size(size_t offset) | |
25 | { | |
26 | size_t size = 0; | |
27 | ||
28 | size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); | |
29 | size += sizeof(unsigned int); | |
30 | return size; | |
31 | } | |
32 | ||
33 | static | |
34 | void uts_ns_record(struct lttng_ctx_field *field, | |
35 | struct lib_ring_buffer_ctx *ctx, | |
36 | struct lttng_channel *chan) | |
37 | { | |
38 | unsigned int uts_ns_inum = 0; | |
39 | ||
40 | /* | |
41 | * nsproxy can be NULL when scheduled out of exit. | |
42 | * | |
43 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
44 | * precautions should be taken when accessing the current task's | |
45 | * namespaces, just dereference the pointers. | |
46 | */ | |
47 | if (current->nsproxy) | |
6388029c | 48 | uts_ns_inum = current->nsproxy->uts_ns->ns.inum; |
a6cf40a4 MJ |
49 | |
50 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(uts_ns_inum)); | |
51 | chan->ops->event_write(ctx, &uts_ns_inum, sizeof(uts_ns_inum)); | |
52 | } | |
53 | ||
54 | static | |
55 | void uts_ns_get_value(struct lttng_ctx_field *field, | |
56 | struct lttng_probe_ctx *lttng_probe_ctx, | |
57 | union lttng_ctx_value *value) | |
58 | { | |
59 | unsigned int uts_ns_inum = 0; | |
60 | ||
61 | /* | |
62 | * nsproxy can be NULL when scheduled out of exit. | |
63 | * | |
64 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
65 | * precautions should be taken when accessing the current task's | |
66 | * namespaces, just dereference the pointers. | |
67 | */ | |
68 | if (current->nsproxy) | |
6388029c | 69 | uts_ns_inum = current->nsproxy->uts_ns->ns.inum; |
a6cf40a4 MJ |
70 | |
71 | value->s64 = uts_ns_inum; | |
72 | } | |
73 | ||
74 | int lttng_add_uts_ns_to_ctx(struct lttng_ctx **ctx) | |
75 | { | |
76 | struct lttng_ctx_field *field; | |
77 | ||
78 | field = lttng_append_context(ctx); | |
79 | if (!field) | |
80 | return -ENOMEM; | |
81 | if (lttng_find_context(*ctx, "uts_ns")) { | |
82 | lttng_remove_context_field(ctx, field); | |
83 | return -EEXIST; | |
84 | } | |
85 | field->event_field.name = "uts_ns"; | |
86 | field->event_field.type.atype = atype_integer; | |
ceabb767 MD |
87 | field->event_field.type.u.integer.size = sizeof(unsigned int) * CHAR_BIT; |
88 | field->event_field.type.u.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT; | |
89 | field->event_field.type.u.integer.signedness = lttng_is_signed_type(unsigned int); | |
90 | field->event_field.type.u.integer.reverse_byte_order = 0; | |
91 | field->event_field.type.u.integer.base = 10; | |
92 | field->event_field.type.u.integer.encoding = lttng_encode_none; | |
a6cf40a4 MJ |
93 | field->get_size = uts_ns_get_size; |
94 | field->record = uts_ns_record; | |
95 | field->get_value = uts_ns_get_value; | |
96 | lttng_context_update(*ctx); | |
a6cf40a4 MJ |
97 | return 0; |
98 | } | |
99 | EXPORT_SYMBOL_GPL(lttng_add_uts_ns_to_ctx); | |
100 | ||
101 | #endif |