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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
a6cf40a4 MJ |
2 | * |
3 | * lttng-context-pid-ns.c | |
4 | * | |
5 | * LTTng pid 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/pid_namespace.h> | |
16 | #include <lttng-events.h> | |
17 | #include <wrapper/ringbuffer/frontend_types.h> | |
a6cf40a4 MJ |
18 | #include <wrapper/namespace.h> |
19 | #include <lttng-tracer.h> | |
20 | ||
21 | #if defined(CONFIG_PID_NS) && \ | |
22 | (LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0)) | |
23 | ||
24 | static | |
25 | size_t pid_ns_get_size(size_t offset) | |
26 | { | |
27 | size_t size = 0; | |
28 | ||
29 | size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); | |
30 | size += sizeof(unsigned int); | |
31 | return size; | |
32 | } | |
33 | ||
34 | static | |
35 | void pid_ns_record(struct lttng_ctx_field *field, | |
36 | struct lib_ring_buffer_ctx *ctx, | |
37 | struct lttng_channel *chan) | |
38 | { | |
39 | struct pid_namespace *ns; | |
40 | unsigned int pid_ns_inum = 0; | |
41 | ||
42 | /* | |
43 | * The pid namespace is an exception -- it's accessed using | |
44 | * task_active_pid_ns. The pid namespace in nsproxy is the | |
45 | * namespace that children will use. | |
46 | */ | |
47 | ns = task_active_pid_ns(current); | |
48 | ||
49 | if (ns) | |
50 | pid_ns_inum = ns->lttng_ns_inum; | |
51 | ||
52 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(pid_ns_inum)); | |
53 | chan->ops->event_write(ctx, &pid_ns_inum, sizeof(pid_ns_inum)); | |
54 | } | |
55 | ||
56 | static | |
57 | void pid_ns_get_value(struct lttng_ctx_field *field, | |
58 | struct lttng_probe_ctx *lttng_probe_ctx, | |
59 | union lttng_ctx_value *value) | |
60 | { | |
61 | struct pid_namespace *ns; | |
62 | unsigned int pid_ns_inum = 0; | |
63 | ||
64 | /* | |
65 | * The pid namespace is an exception -- it's accessed using | |
66 | * task_active_pid_ns. The pid namespace in nsproxy is the | |
67 | * namespace that children will use. | |
68 | */ | |
69 | ns = task_active_pid_ns(current); | |
70 | ||
71 | if (ns) | |
72 | pid_ns_inum = ns->lttng_ns_inum; | |
73 | ||
74 | value->s64 = pid_ns_inum; | |
75 | } | |
76 | ||
77 | int lttng_add_pid_ns_to_ctx(struct lttng_ctx **ctx) | |
78 | { | |
79 | struct lttng_ctx_field *field; | |
80 | ||
81 | field = lttng_append_context(ctx); | |
82 | if (!field) | |
83 | return -ENOMEM; | |
84 | if (lttng_find_context(*ctx, "pid_ns")) { | |
85 | lttng_remove_context_field(ctx, field); | |
86 | return -EEXIST; | |
87 | } | |
88 | field->event_field.name = "pid_ns"; | |
89 | field->event_field.type.atype = atype_integer; | |
ceabb767 MD |
90 | field->event_field.type.u.integer.size = sizeof(unsigned int) * CHAR_BIT; |
91 | field->event_field.type.u.integer.alignment = lttng_alignof(unsigned int) * CHAR_BIT; | |
92 | field->event_field.type.u.integer.signedness = lttng_is_signed_type(unsigned int); | |
93 | field->event_field.type.u.integer.reverse_byte_order = 0; | |
94 | field->event_field.type.u.integer.base = 10; | |
95 | field->event_field.type.u.integer.encoding = lttng_encode_none; | |
a6cf40a4 MJ |
96 | field->get_size = pid_ns_get_size; |
97 | field->record = pid_ns_record; | |
98 | field->get_value = pid_ns_get_value; | |
99 | lttng_context_update(*ctx); | |
a6cf40a4 MJ |
100 | return 0; |
101 | } | |
102 | EXPORT_SYMBOL_GPL(lttng_add_pid_ns_to_ctx); | |
103 | ||
104 | #endif |