2 * (C) Copyright 2009-2011 -
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 * LTTng UST vpid context.
7 * Dual LGPL v2.1/GPL v2 license.
10 #include <sys/types.h>
12 #include <ust/lttng-events.h>
13 #include <ust/lttng-tracer.h>
14 #include <ust/ringbuffer-config.h>
18 pid_t
wrapper_getpid(void)
23 void lttng_context_vpid_reset(void)
28 * We cache the result to ensure we don't trigger a system call for
31 static pid_t cached_vpid
;
34 pid_t
wrapper_getpid(void)
36 if (caa_unlikely(!cached_vpid
))
37 cached_vpid
= getpid();
42 * Upon fork or clone, the PID assigned to our thread is not the same as
45 void lttng_context_vpid_reset(void)
52 size_t vpid_get_size(size_t offset
)
56 size
+= lib_ring_buffer_align(offset
, lttng_alignof(pid_t
));
57 size
+= sizeof(pid_t
);
62 void vpid_record(struct lttng_ctx_field
*field
,
63 struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
64 struct ltt_channel
*chan
)
68 pid
= wrapper_getpid();
69 lib_ring_buffer_align_ctx(ctx
, lttng_alignof(pid
));
70 chan
->ops
->event_write(ctx
, &pid
, sizeof(pid
));
73 int lttng_add_vpid_to_ctx(struct lttng_ctx
**ctx
)
75 struct lttng_ctx_field
*field
;
77 field
= lttng_append_context(ctx
);
80 if (lttng_find_context(*ctx
, "vpid")) {
81 lttng_remove_context_field(ctx
, field
);
84 field
->event_field
.name
= "vpid";
85 field
->event_field
.type
.atype
= atype_integer
;
86 field
->event_field
.type
.u
.basic
.integer
.size
= sizeof(pid_t
) * CHAR_BIT
;
87 field
->event_field
.type
.u
.basic
.integer
.alignment
= lttng_alignof(pid_t
) * CHAR_BIT
;
88 field
->event_field
.type
.u
.basic
.integer
.signedness
= lttng_is_signed_type(pid_t
);
89 field
->event_field
.type
.u
.basic
.integer
.reverse_byte_order
= 0;
90 field
->event_field
.type
.u
.basic
.integer
.base
= 10;
91 field
->event_field
.type
.u
.basic
.integer
.encoding
= lttng_encode_none
;
92 field
->get_size
= vpid_get_size
;
93 field
->record
= vpid_record
;