2 * (C) Copyright 2009-2011 -
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 * LTTng UST procname context.
7 * Dual LGPL v2.1/GPL v2 license.
10 #include <lttng/ust-events.h>
11 #include <lttng/ust-tracer.h>
12 #include <lttng/ringbuffer-config.h>
17 * We cache the result to ensure we don't trigger a system call for
19 * Upon exec, procname changes, but exec takes care of throwing away
20 * this cached version.
22 static char cached_procname
[17];
25 char *wrapper_getprocname(void)
27 if (caa_unlikely(!cached_procname
[0])) {
28 lttng_ust_getprocname(cached_procname
);
29 cached_procname
[LTTNG_UST_PROCNAME_LEN
- 1] = '\0';
31 return cached_procname
;
34 void lttng_context_procname_reset(void)
36 cached_procname
[0] = '\0';
40 size_t procname_get_size(size_t offset
)
44 size
+= LTTNG_UST_PROCNAME_LEN
;
49 void procname_record(struct lttng_ctx_field
*field
,
50 struct lttng_ust_lib_ring_buffer_ctx
*ctx
,
51 struct ltt_channel
*chan
)
55 procname
= wrapper_getprocname();
56 chan
->ops
->event_write(ctx
, procname
, LTTNG_UST_PROCNAME_LEN
);
59 int lttng_add_procname_to_ctx(struct lttng_ctx
**ctx
)
61 struct lttng_ctx_field
*field
;
63 field
= lttng_append_context(ctx
);
66 if (lttng_find_context(*ctx
, "procname")) {
67 lttng_remove_context_field(ctx
, field
);
70 field
->event_field
.name
= "procname";
71 field
->event_field
.type
.atype
= atype_array
;
72 field
->event_field
.type
.u
.array
.elem_type
.atype
= atype_integer
;
73 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.size
= sizeof(char) * CHAR_BIT
;
74 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.alignment
= lttng_alignof(char) * CHAR_BIT
;
75 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.signedness
= lttng_is_signed_type(char);
76 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.reverse_byte_order
= 0;
77 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.base
= 10;
78 field
->event_field
.type
.u
.array
.elem_type
.u
.basic
.integer
.encoding
= lttng_encode_UTF8
;
79 field
->event_field
.type
.u
.array
.length
= LTTNG_UST_PROCNAME_LEN
;
80 field
->get_size
= procname_get_size
;
81 field
->record
= procname_record
;