2 * lttng-context-vppid.c
6 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/sched.h>
26 #include <linux/syscalls.h>
27 #include <lttng-events.h>
28 #include <wrapper/ringbuffer/frontend_types.h>
29 #include <wrapper/vmalloc.h>
30 #include <lttng-tracer.h>
33 size_t vppid_get_size(size_t offset
)
37 size
+= lib_ring_buffer_align(offset
, lttng_alignof(pid_t
));
38 size
+= sizeof(pid_t
);
43 void vppid_record(struct lttng_ctx_field
*field
,
44 struct lib_ring_buffer_ctx
*ctx
,
45 struct lttng_channel
*chan
)
47 struct task_struct
*parent
;
51 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
52 * the current thread nsproxy to perform the lookup.
56 * TODO: when we eventually add RCU subsystem instrumentation,
57 * taking the rcu read lock here will trigger RCU tracing
58 * recursively. We should modify the kernel synchronization so
59 * it synchronizes both for RCU and RCU sched, and rely on
60 * rcu_read_lock_sched_notrace.
64 parent
= rcu_dereference(current
->real_parent
);
65 if (!current
->nsproxy
)
68 vppid
= task_tgid_vnr(parent
);
70 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(vppid
));
71 chan
->ops
->event_write(ctx
, &vppid
, sizeof(vppid
));
75 void vppid_get_value(struct lttng_ctx_field
*field
,
76 struct lttng_probe_ctx
*lttng_probe_ctx
,
77 union lttng_ctx_value
*value
)
79 struct task_struct
*parent
;
83 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
84 * the current thread nsproxy to perform the lookup.
88 * TODO: when we eventually add RCU subsystem instrumentation,
89 * taking the rcu read lock here will trigger RCU tracing
90 * recursively. We should modify the kernel synchronization so
91 * it synchronizes both for RCU and RCU sched, and rely on
92 * rcu_read_lock_sched_notrace.
96 parent
= rcu_dereference(current
->real_parent
);
97 if (!current
->nsproxy
)
100 vppid
= task_tgid_vnr(parent
);
105 int lttng_add_vppid_to_ctx(struct lttng_ctx
**ctx
)
107 struct lttng_ctx_field
*field
;
109 field
= lttng_append_context(ctx
);
112 if (lttng_find_context(*ctx
, "vppid")) {
113 lttng_remove_context_field(ctx
, field
);
116 field
->event_field
.name
= "vppid";
117 field
->event_field
.type
.atype
= atype_integer
;
118 field
->event_field
.type
.u
.basic
.integer
.size
= sizeof(pid_t
) * CHAR_BIT
;
119 field
->event_field
.type
.u
.basic
.integer
.alignment
= lttng_alignof(pid_t
) * CHAR_BIT
;
120 field
->event_field
.type
.u
.basic
.integer
.signedness
= lttng_is_signed_type(pid_t
);
121 field
->event_field
.type
.u
.basic
.integer
.reverse_byte_order
= 0;
122 field
->event_field
.type
.u
.basic
.integer
.base
= 10;
123 field
->event_field
.type
.u
.basic
.integer
.encoding
= lttng_encode_none
;
124 field
->get_size
= vppid_get_size
;
125 field
->record
= vppid_record
;
126 field
->get_value
= vppid_get_value
;
127 lttng_context_update(*ctx
);
128 wrapper_vmalloc_sync_all();
131 EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx
);
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