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1 | /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) |
2 | * | |
3 | * lttng-context-ipc-ns.c | |
4 | * | |
5 | * LTTng ipc 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/ipc_namespace.h> | |
16 | #include <lttng-events.h> | |
17 | #include <wrapper/ringbuffer/frontend_types.h> | |
18 | #include <wrapper/vmalloc.h> | |
19 | #include <wrapper/namespace.h> | |
20 | #include <lttng-tracer.h> | |
21 | ||
22 | #if defined(CONFIG_IPC_NS) && \ | |
23 | (LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0)) | |
24 | ||
25 | static | |
26 | size_t ipc_ns_get_size(size_t offset) | |
27 | { | |
28 | size_t size = 0; | |
29 | ||
30 | size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); | |
31 | size += sizeof(unsigned int); | |
32 | return size; | |
33 | } | |
34 | ||
35 | static | |
36 | void ipc_ns_record(struct lttng_ctx_field *field, | |
37 | struct lib_ring_buffer_ctx *ctx, | |
38 | struct lttng_channel *chan) | |
39 | { | |
40 | unsigned int ipc_ns_inum = 0; | |
41 | ||
42 | /* | |
43 | * nsproxy can be NULL when scheduled out of exit. | |
44 | * | |
45 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
46 | * precautions should be taken when accessing the current task's | |
47 | * namespaces, just dereference the pointers. | |
48 | */ | |
49 | if (current->nsproxy) | |
50 | ipc_ns_inum = current->nsproxy->ipc_ns->lttng_ns_inum; | |
51 | ||
52 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(ipc_ns_inum)); | |
53 | chan->ops->event_write(ctx, &ipc_ns_inum, sizeof(ipc_ns_inum)); | |
54 | } | |
55 | ||
56 | static | |
57 | void ipc_ns_get_value(struct lttng_ctx_field *field, | |
58 | struct lttng_probe_ctx *lttng_probe_ctx, | |
59 | union lttng_ctx_value *value) | |
60 | { | |
61 | unsigned int ipc_ns_inum = 0; | |
62 | ||
63 | /* | |
64 | * nsproxy can be NULL when scheduled out of exit. | |
65 | * | |
66 | * As documented in 'linux/nsproxy.h' namespaces access rules, no | |
67 | * precautions should be taken when accessing the current task's | |
68 | * namespaces, just dereference the pointers. | |
69 | */ | |
70 | if (current->nsproxy) | |
71 | ipc_ns_inum = current->nsproxy->ipc_ns->lttng_ns_inum; | |
72 | ||
73 | value->s64 = ipc_ns_inum; | |
74 | } | |
75 | ||
76 | int lttng_add_ipc_ns_to_ctx(struct lttng_ctx **ctx) | |
77 | { | |
78 | struct lttng_ctx_field *field; | |
79 | ||
80 | field = lttng_append_context(ctx); | |
81 | if (!field) | |
82 | return -ENOMEM; | |
83 | if (lttng_find_context(*ctx, "ipc_ns")) { | |
84 | lttng_remove_context_field(ctx, field); | |
85 | return -EEXIST; | |
86 | } | |
87 | field->event_field.name = "ipc_ns"; | |
88 | field->event_field.type.atype = atype_integer; | |
89 | field->event_field.type.u.basic.integer.size = sizeof(unsigned int) * CHAR_BIT; | |
90 | field->event_field.type.u.basic.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT; | |
91 | field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(unsigned int); | |
92 | field->event_field.type.u.basic.integer.reverse_byte_order = 0; | |
93 | field->event_field.type.u.basic.integer.base = 10; | |
94 | field->event_field.type.u.basic.integer.encoding = lttng_encode_none; | |
95 | field->get_size = ipc_ns_get_size; | |
96 | field->record = ipc_ns_record; | |
97 | field->get_value = ipc_ns_get_value; | |
98 | lttng_context_update(*ctx); | |
99 | wrapper_vmalloc_sync_all(); | |
100 | return 0; | |
101 | } | |
102 | EXPORT_SYMBOL_GPL(lttng_add_ipc_ns_to_ctx); | |
103 | ||
104 | #endif |