X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-context-procname.c;h=2e2c7fa2ef14a6227007f6746c752d42923fc947;hb=8936b6c0add7eb6706e0a1ca50e03c446dda4006;hp=0e7bf1ce6080ed264be4335dfc8f9de6334273a0;hpb=8c90a710949a214d87084ff67fc85f284bc93ef2;p=lttng-ust.git diff --git a/liblttng-ust/lttng-context-procname.c b/liblttng-ust/lttng-context-procname.c index 0e7bf1ce..2e2c7fa2 100644 --- a/liblttng-ust/lttng-context-procname.c +++ b/liblttng-ust/lttng-context-procname.c @@ -1,32 +1,25 @@ /* - * lttng-context-procname.c - * - * LTTng UST procname context. + * SPDX-License-Identifier: LGPL-2.1-only * * Copyright (C) 2009-2012 Mathieu Desnoyers * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * LTTng UST procname context. */ +#define _LGPL_SOURCE +#include #include #include -#include +#include #include #include #include "compat.h" +#include "context-internal.h" + +/* Maximum number of nesting levels for the procname cache. */ +#define PROCNAME_NESTING_MAX 2 + /* * We cache the result to ensure we don't trigger a system call for * each event. @@ -36,68 +29,101 @@ * be set for a thread before the first event is logged within this * thread. */ -typedef char procname_array[17]; +typedef char procname_array[PROCNAME_NESTING_MAX][17]; + static DEFINE_URCU_TLS(procname_array, cached_procname); +static DEFINE_URCU_TLS(int, procname_nesting); + static inline char *wrapper_getprocname(void) { - if (caa_unlikely(!URCU_TLS(cached_procname)[0])) { - lttng_ust_getprocname(URCU_TLS(cached_procname)); - URCU_TLS(cached_procname)[LTTNG_UST_PROCNAME_LEN - 1] = '\0'; + int nesting = CMM_LOAD_SHARED(URCU_TLS(procname_nesting)); + + if (caa_unlikely(nesting >= PROCNAME_NESTING_MAX)) + return ""; + if (caa_unlikely(!URCU_TLS(cached_procname)[nesting][0])) { + CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting + 1); + /* Increment nesting before updating cache. */ + cmm_barrier(); + lttng_pthread_getname_np(URCU_TLS(cached_procname)[nesting], LTTNG_UST_ABI_PROCNAME_LEN); + URCU_TLS(cached_procname)[nesting][LTTNG_UST_ABI_PROCNAME_LEN - 1] = '\0'; + /* Decrement nesting after updating cache. */ + cmm_barrier(); + CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting); } - return URCU_TLS(cached_procname); + return URCU_TLS(cached_procname)[nesting]; } -void lttng_context_procname_reset(void) +/* Reset should not be called from a signal handler. */ +void lttng_ust_context_procname_reset(void) { - URCU_TLS(cached_procname)[0] = '\0'; + CMM_STORE_SHARED(URCU_TLS(cached_procname)[1][0], '\0'); + CMM_STORE_SHARED(URCU_TLS(procname_nesting), 1); + CMM_STORE_SHARED(URCU_TLS(cached_procname)[0][0], '\0'); + CMM_STORE_SHARED(URCU_TLS(procname_nesting), 0); } static -size_t procname_get_size(size_t offset) +size_t procname_get_size(struct lttng_ust_ctx_field *field, size_t offset) { - size_t size = 0; - - size += LTTNG_UST_PROCNAME_LEN; - return size; + return LTTNG_UST_ABI_PROCNAME_LEN; } static -void procname_record(struct lttng_ctx_field *field, +void procname_record(struct lttng_ust_ctx_field *field, struct lttng_ust_lib_ring_buffer_ctx *ctx, - struct lttng_channel *chan) + struct lttng_ust_channel_buffer *chan) { char *procname; procname = wrapper_getprocname(); - chan->ops->event_write(ctx, procname, LTTNG_UST_PROCNAME_LEN); + chan->ops->event_write(ctx, procname, LTTNG_UST_ABI_PROCNAME_LEN, 1); } -int lttng_add_procname_to_ctx(struct lttng_ctx **ctx) +static +void procname_get_value(struct lttng_ust_ctx_field *field, + struct lttng_ust_ctx_value *value) { - struct lttng_ctx_field *field; + value->u.str = wrapper_getprocname(); +} - field = lttng_append_context(ctx); - if (!field) +int lttng_add_procname_to_ctx(struct lttng_ust_ctx **ctx) +{ + struct lttng_ust_ctx_field *field; + struct lttng_ust_type_common *type; + int ret; + + type = lttng_ust_create_type_array_text(LTTNG_UST_ABI_PROCNAME_LEN); + if (!type) return -ENOMEM; + field = lttng_append_context(ctx); + if (!field) { + ret = -ENOMEM; + goto error_context; + } if (lttng_find_context(*ctx, "procname")) { - lttng_remove_context_field(ctx, field); - return -EEXIST; + ret = -EEXIST; + goto error_find_context; } - field->event_field.name = "procname"; - field->event_field.type.atype = atype_array; - field->event_field.type.u.array.elem_type.atype = atype_integer; - field->event_field.type.u.array.elem_type.u.basic.integer.size = sizeof(char) * CHAR_BIT; - field->event_field.type.u.array.elem_type.u.basic.integer.alignment = lttng_alignof(char) * CHAR_BIT; - field->event_field.type.u.array.elem_type.u.basic.integer.signedness = lttng_is_signed_type(char); - field->event_field.type.u.array.elem_type.u.basic.integer.reverse_byte_order = 0; - field->event_field.type.u.array.elem_type.u.basic.integer.base = 10; - field->event_field.type.u.array.elem_type.u.basic.integer.encoding = lttng_encode_UTF8; - field->event_field.type.u.array.length = LTTNG_UST_PROCNAME_LEN; + field->event_field->name = strdup("procname"); + if (!field->event_field->name) { + ret = -ENOMEM; + goto error_name; + } + field->event_field->type = type; field->get_size = procname_get_size; field->record = procname_record; + field->get_value = procname_get_value; + lttng_context_update(*ctx); return 0; + +error_name: +error_find_context: + lttng_remove_context_field(ctx, field); +error_context: + lttng_ust_destroy_type(type); + return ret; } /*