+++ /dev/null
-/*
- * lttng-context-ipc-ns.c
- *
- * LTTng UST ipc namespace context.
- *
- * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * 2019 Michael Jeanson <mjeanson@efficios.com>
- *
- * 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
- */
-
-#define _LGPL_SOURCE
-#include <stddef.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <lttng/ust-events.h>
-#include <lttng/ust-tracer.h>
-#include <lttng/ringbuffer-config.h>
-#include <lttng/ust-tid.h>
-#include <urcu/tls-compat.h>
-#include "lttng-tracer-core.h"
-#include "ns.h"
-
-/*
- * We cache the result to ensure we don't stat(2) the proc filesystem on
- * each event.
- */
-#ifdef CONFIG_RCU_TLS
-static DEFINE_URCU_TLS(ino_t, cached_ipc_ns) = NS_INO_UNINITIALIZED;
-#else
-static DEFINE_URCU_TLS_INIT(ino_t, cached_ipc_ns, NS_INO_UNINITIALIZED);
-#endif
-
-static
-ino_t get_ipc_ns(void)
-{
- struct stat sb;
- ino_t ipc_ns;
-
- ipc_ns = CMM_LOAD_SHARED(URCU_TLS(cached_ipc_ns));
-
- /*
- * If the cache is populated, do nothing and return the
- * cached inode number.
- */
- if (caa_likely(ipc_ns != NS_INO_UNINITIALIZED))
- return ipc_ns;
-
- /*
- * At this point we have to populate the cache, set the initial
- * value to NS_INO_UNAVAILABLE (0), if we fail to get the inode
- * number from the proc filesystem, this is the value we will
- * cache.
- */
- ipc_ns = NS_INO_UNAVAILABLE;
-
- /*
- * /proc/thread-self was introduced in kernel v3.17
- */
- if (stat("/proc/thread-self/ns/ipc", &sb) == 0) {
- ipc_ns = sb.st_ino;
- } else {
- char proc_ns_path[LTTNG_PROC_NS_PATH_MAX];
-
- if (snprintf(proc_ns_path, LTTNG_PROC_NS_PATH_MAX,
- "/proc/self/task/%d/ns/ipc",
- lttng_gettid()) >= 0) {
-
- if (stat(proc_ns_path, &sb) == 0) {
- ipc_ns = sb.st_ino;
- }
- }
- }
-
- /*
- * And finally, store the inode number in the cache.
- */
- CMM_STORE_SHARED(URCU_TLS(cached_ipc_ns), ipc_ns);
-
- return ipc_ns;
-}
-
-/*
- * The ipc namespace can change for 3 reasons
- * * clone(2) called with CLONE_NEWIPC
- * * setns(2) called with the fd of a different ipc ns
- * * unshare(2) called with CLONE_NEWIPC
- */
-void lttng_context_ipc_ns_reset(void)
-{
- CMM_STORE_SHARED(URCU_TLS(cached_ipc_ns), NS_INO_UNINITIALIZED);
-}
-
-static
-size_t ipc_ns_get_size(struct lttng_ctx_field *field, size_t offset)
-{
- size_t size = 0;
-
- size += lib_ring_buffer_align(offset, lttng_alignof(ino_t));
- size += sizeof(ino_t);
- return size;
-}
-
-static
-void ipc_ns_record(struct lttng_ctx_field *field,
- struct lttng_ust_lib_ring_buffer_ctx *ctx,
- struct lttng_channel *chan)
-{
- ino_t ipc_ns;
-
- ipc_ns = get_ipc_ns();
- lib_ring_buffer_align_ctx(ctx, lttng_alignof(ipc_ns));
- chan->ops->event_write(ctx, &ipc_ns, sizeof(ipc_ns));
-}
-
-static
-void ipc_ns_get_value(struct lttng_ctx_field *field,
- struct lttng_ctx_value *value)
-{
- value->u.s64 = get_ipc_ns();
-}
-
-int lttng_add_ipc_ns_to_ctx(struct lttng_ctx **ctx)
-{
- struct lttng_ctx_field *field;
-
- field = lttng_append_context(ctx);
- if (!field)
- return -ENOMEM;
- if (lttng_find_context(*ctx, "ipc_ns")) {
- lttng_remove_context_field(ctx, field);
- return -EEXIST;
- }
- field->event_field.name = "ipc_ns";
- field->event_field.type.atype = atype_integer;
- field->event_field.type.u.basic.integer.size = sizeof(ino_t) * CHAR_BIT;
- field->event_field.type.u.basic.integer.alignment = lttng_alignof(ino_t) * CHAR_BIT;
- field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(ino_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 = ipc_ns_get_size;
- field->record = ipc_ns_record;
- field->get_value = ipc_ns_get_value;
- lttng_context_update(*ctx);
- return 0;
-}
-
-/*
- * * Force a read (imply TLS fixup for dlopen) of TLS variables.
- * */
-void lttng_fixup_ipc_ns_tls(void)
-{
- asm volatile ("" : : "m" (URCU_TLS(cached_ipc_ns)));
-}