Refactoring: add back constness of public API structures

[lttng-ust.git] / liblttng-ust / lttng-context-vtid.c

diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c
index 22261f55e02173a6ffdf29370dfb879453c64f23..3530d2668757269d6139369bbae19b0a14912c1f 100644 (file)
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -1,43 +1,30 @@
 /*
- * (C) Copyright       2009-2011 -
- *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * LTTng UST vtid context.
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * LTTng UST vtid context.
  */
 
+#define _LGPL_SOURCE
+#include <limits.h>
+#include <stddef.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
-#include <lttng/ringbuffer-config.h>
-#include "ltt-tracer-core.h"
-
-#ifdef __linux__
-#include <syscall.h>
-#endif
+#include <lttng/ringbuffer-context.h>
+#include <ust-tid.h>
+#include <urcu/tls-compat.h>
 
-#if defined(_syscall0)
-_syscall0(pid_t, gettid)
-#elif defined(__NR_gettid)
-static inline pid_t gettid(void)
-{
-       return syscall(__NR_gettid);
-}
-#else
-#warning "use pid as tid"
-static inline pid_t gettid(void)
-{
-       return getpid();
-}
-#endif
+#include "context-internal.h"
+#include "lttng-tracer-core.h"
 
 /*
  * We cache the result to ensure we don't trigger a system call for
  * each event.
  */
-static __thread pid_t cached_vtid;
+static DEFINE_URCU_TLS(pid_t, cached_vtid);
 
 /*
  * Upon fork or clone, the TID assigned to our thread is not the same as
@@ -46,52 +33,77 @@ static __thread pid_t cached_vtid;
  */
 void lttng_context_vtid_reset(void)
 {
-       cached_vtid = 0;
+       CMM_STORE_SHARED(URCU_TLS(cached_vtid), 0);
 }
 
 static
-size_t vtid_get_size(size_t offset)
+size_t vtid_get_size(void *priv __attribute__((unused)),
+               size_t offset)
 {
        size_t size = 0;
 
-       size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
+       size += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(pid_t));
        size += sizeof(pid_t);
        return size;
 }
 
+static inline
+pid_t wrapper_getvtid(void)
+{
+       pid_t vtid;
+
+       vtid = CMM_LOAD_SHARED(URCU_TLS(cached_vtid));
+       if (caa_unlikely(!vtid)) {
+               vtid = lttng_gettid();
+               CMM_STORE_SHARED(URCU_TLS(cached_vtid), vtid);
+       }
+       return vtid;
+}
+
 static
-void vtid_record(struct lttng_ctx_field *field,
+void vtid_record(void *priv __attribute__((unused)),
                 struct lttng_ust_lib_ring_buffer_ctx *ctx,
-                struct ltt_channel *chan)
+                struct lttng_ust_channel_buffer *chan)
+{
+       pid_t vtid = wrapper_getvtid();
+
+       chan->ops->event_write(ctx, &vtid, sizeof(vtid), lttng_ust_rb_alignof(vtid));
+}
+
+static
+void vtid_get_value(void *priv __attribute__((unused)),
+               struct lttng_ust_ctx_value *value)
 {
-       if (caa_unlikely(!cached_vtid))
-               cached_vtid = gettid();
-       lib_ring_buffer_align_ctx(ctx, lttng_alignof(cached_vtid));
-       chan->ops->event_write(ctx, &cached_vtid, sizeof(cached_vtid));
+       value->u.s64 = wrapper_getvtid();
 }
 
-int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
+static const struct lttng_ust_ctx_field *ctx_field = lttng_ust_static_ctx_field(
+       lttng_ust_static_event_field("vtid",
+               lttng_ust_static_type_integer(sizeof(pid_t) * CHAR_BIT,
+                               lttng_ust_rb_alignof(pid_t) * CHAR_BIT,
+                               lttng_ust_is_signed_type(pid_t),
+                               BYTE_ORDER, 10),
+               false, false),
+       vtid_get_size,
+       vtid_record,
+       vtid_get_value,
+       NULL, NULL);
+
+int lttng_add_vtid_to_ctx(struct lttng_ust_ctx **ctx)
 {
-       struct lttng_ctx_field *field;
-
-       field = lttng_append_context(ctx);
-       if (!field)
-               return -ENOMEM;
-       if (lttng_find_context(*ctx, "vtid")) {
-               lttng_remove_context_field(ctx, field);
-               return -EEXIST;
+       int ret;
+
+       if (lttng_find_context(*ctx, ctx_field->event_field->name)) {
+               ret = -EEXIST;
+               goto error_find_context;
        }
-       field->event_field.name = "vtid";
-       field->event_field.type.atype = atype_integer;
-       field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
-       field->event_field.type.u.basic.integer.reverse_byte_order = 0;
-       field->event_field.type.u.basic.integer.base = 10;
-       field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
-       field->get_size = vtid_get_size;
-       field->record = vtid_record;
+       ret = lttng_ust_context_append(ctx, ctx_field);
+       if (ret)
+               return ret;
        return 0;
+
+error_find_context:
+       return ret;
 }
 
 /*
@@ -99,5 +111,5 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
  */
 void lttng_fixup_vtid_tls(void)
 {
-       asm volatile ("" : : "m" (cached_vtid));
+       asm volatile ("" : : "m" (URCU_TLS(cached_vtid)));
 }