[lttng-dev] [PATCH v2 2/2] Implement base-address-state tracing
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Thu Nov 14 11:30:57 EST 2013
----- Original Message -----
> From: "Paul Woegerer" <paul_woegerer at mentor.com>
> To: lttng-dev at lists.lttng.org, "mathieu desnoyers" <mathieu.desnoyers at efficios.com>
> Sent: Wednesday, November 13, 2013 1:37:40 PM
> Subject: [PATCH v2 2/2] Implement base-address-state tracing
>
> Dump the base-address state (executable and shared objects) into session
> on session-enable (per-session events).
>
> Signed-off-by: Paul Woegerer <paul_woegerer at mentor.com>
> ---
> include/lttng/ust-tracepoint-event.h | 14 +++++++
> liblttng-ust-baddr/Makefile.am | 4 +-
> liblttng-ust-baddr/lttng-ust-baddr.c | 64
> ++++++++++++++++++++++++++++++++
> liblttng-ust-baddr/ust_baddr_statedump.c | 21 +++++++++++
> liblttng-ust-baddr/ust_baddr_statedump.h | 60 ++++++++++++++++++++++++++++++
> liblttng-ust/lttng-events.c | 4 ++
> liblttng-ust/lttng-ust-comm.c | 62
> +++++++++++++++++++++++++++++++
> 7 files changed, 228 insertions(+), 1 deletion(-)
> create mode 100644 liblttng-ust-baddr/ust_baddr_statedump.c
> create mode 100644 liblttng-ust-baddr/ust_baddr_statedump.h
>
> diff --git a/include/lttng/ust-tracepoint-event.h
> b/include/lttng/ust-tracepoint-event.h
> index bb3a05d..be58030 100644
> --- a/include/lttng/ust-tracepoint-event.h
> +++ b/include/lttng/ust-tracepoint-event.h
> @@ -480,6 +480,18 @@ size_t
> __event_get_align__##_provider##___##_name(_TP_ARGS_PROTO(_args)) \
> #define TP_FIELDS(...) __VA_ARGS__
>
> /*
> + * For state dump, check that "session" argument (mandatory) matches the
> + * session this event belongs to. Ensures that we write state dump data only
> + * into the started session, not into all sessions.
> + */
> +#undef _TP_SESSION_CHECK
> +#ifdef TP_SESSION_CHECK
> +#define _TP_SESSION_CHECK(session, csession) (session == csession)
> +#else /* TP_SESSION_CHECK */
> +#define _TP_SESSION_CHECK(session, csession) 1
> +#endif /* TP_SESSION_CHECK */
> +
> +/*
> * Using twice size for filter stack data to hold size and pointer for
> * each field (worse case). For integers, max size required is 64-bit.
> * Same for double-precision floats. Those fit within
> @@ -506,6 +518,8 @@ void
> __event_probe__##_provider##___##_name(_TP_ARGS_DATA_PROTO(_args)) \
> \
> if (0) \
> (void) __dynamic_len_idx; /* don't warn if unused */ \
> + if (!_TP_SESSION_CHECK(session, __chan->session)) \
> + return; \
> if (caa_unlikely(!CMM_ACCESS_ONCE(__chan->session->active))) \
> return; \
> if (caa_unlikely(!CMM_ACCESS_ONCE(__chan->enabled))) \
> diff --git a/liblttng-ust-baddr/Makefile.am b/liblttng-ust-baddr/Makefile.am
> index afa9489..0d3cf28 100644
> --- a/liblttng-ust-baddr/Makefile.am
> +++ b/liblttng-ust-baddr/Makefile.am
> @@ -5,7 +5,9 @@ lib_LTLIBRARIES = liblttng-ust-baddr.la
> liblttng_ust_baddr_la_SOURCES = \
> lttng-ust-baddr.c \
> ust_baddr.c \
> - ust_baddr.h
> + ust_baddr.h \
> + ust_baddr_statedump.c \
> + ust_baddr_statedump.h
> liblttng_ust_baddr_la_LIBADD = \
> -L$(top_builddir)/liblttng-ust/.libs \
> -llttng-ust
> diff --git a/liblttng-ust-baddr/lttng-ust-baddr.c
> b/liblttng-ust-baddr/lttng-ust-baddr.c
> index 21c22a2..f73bf0d 100644
> --- a/liblttng-ust-baddr/lttng-ust-baddr.c
> +++ b/liblttng-ust-baddr/lttng-ust-baddr.c
> @@ -34,6 +34,7 @@
>
> #define TRACEPOINT_DEFINE
> #include "ust_baddr.h"
> +#include "ust_baddr_statedump.h"
>
> int
> push_baddr(void *so_base, const char *so_name)
> @@ -62,3 +63,66 @@ pop_baddr(void *so_base)
> tracepoint(ust_baddr, pop, so_base);
> return 0;
> }
> +
> +static int
> +extract_soinfo_events(struct dl_phdr_info *info, size_t size, void *data)
> +{
> + int j;
> + int num_loadable_segment = 0;
> +
> + for (j = 0; j < info->dlpi_phnum; j++) {
> + char resolved_path[PATH_MAX];
> + struct stat sostat;
> + void *base_addr_ptr;
> +
> + if (info->dlpi_phdr[j].p_type != PT_LOAD)
> + continue;
> +
> + /* Calculate virtual memory address of the loadable segment */
> + base_addr_ptr = (void *) info->dlpi_addr
> + + info->dlpi_phdr[j].p_vaddr;
> +
> + num_loadable_segment += 1;
> + if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0)
> + && num_loadable_segment == 1) {
> + /* If the iterated element is the executable itself we
> + * have to use Dl_info to determine its full path */
small nit: multi line comments should be like this:
/*
* Comment..
* continue....
*/
(throughout the patch)
> + Dl_info dl_info = { 0 };
> + if (!dladdr(base_addr_ptr, &dl_info))
> + return 0;
> + if (!realpath(dl_info.dli_fname, resolved_path))
> + return 0;
> + } else {
> + /* For regular dl_phdr_info entries we have to check if
> + * the path to the shared object really exists */
> + if (!realpath(info->dlpi_name, resolved_path)) {
> + /* Found vDSO, put the 'path' into brackets */
> + snprintf(resolved_path, PATH_MAX - 1, "[%s]",
> + info->dlpi_name);
> + }
> + }
> +
> + if (stat(resolved_path, &sostat)) {
> + sostat.st_size = 0;
> + sostat.st_mtime = -1;
> + }
> +
> + tracepoint(ust_baddr_statedump, soinfo,
> + (struct lttng_session *) data, base_addr_ptr,
> + resolved_path, sostat.st_size, sostat.st_mtime);
> +
> + /* We are only interrested in the base address (lowest virtual
interrested -> interested
> + * address associated with the memory image), skip the rest */
Ah that makes the "break" much clearer now :)
> + break;
> + }
> + return 0;
> +}
> +
> +int
> +baddr_statedump(struct lttng_session *session)
> +{
> + /* Iterate through the list of currently loaded shared objects and
> + * generate events for loadable segments using extract_soinfo_events */
> + dl_iterate_phdr(extract_soinfo_events, session);
> + return 0;
> +}
> diff --git a/liblttng-ust-baddr/ust_baddr_statedump.c
> b/liblttng-ust-baddr/ust_baddr_statedump.c
> new file mode 100644
> index 0000000..75f74ca
> --- /dev/null
> +++ b/liblttng-ust-baddr/ust_baddr_statedump.c
> @@ -0,0 +1,21 @@
> +/*
> + * Copyright (C) 2013 Paul Woegerer <paul_woegerer at mentor.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; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * 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 TRACEPOINT_CREATE_PROBES
> +#define TP_SESSION_CHECK
> +#include "ust_baddr_statedump.h"
> diff --git a/liblttng-ust-baddr/ust_baddr_statedump.h
> b/liblttng-ust-baddr/ust_baddr_statedump.h
> new file mode 100644
> index 0000000..77a9af4
> --- /dev/null
> +++ b/liblttng-ust-baddr/ust_baddr_statedump.h
> @@ -0,0 +1,60 @@
> +#undef TRACEPOINT_PROVIDER
> +#define TRACEPOINT_PROVIDER ust_baddr_statedump
> +
> +#if !defined(_TRACEPOINT_UST_BADDR_STATEDUMP_H) ||
> defined(TRACEPOINT_HEADER_MULTI_READ)
> +#define _TRACEPOINT_UST_BADDR_STATEDUMP_H
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/*
> + * Copyright (C) 2013 Paul Woegerer <paul_woegerer at mentor.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included
> in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
> OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> THE
> + * SOFTWARE.
> + */
> +
> +#include <stdint.h>
> +#include <unistd.h>
> +#include <lttng/ust-events.h>
> +
> +#define LTTNG_UST_BADDR_STATEDUMP_PROVIDER
> +#include <lttng/tracepoint.h>
> +
> +TRACEPOINT_EVENT(ust_baddr_statedump, soinfo,
> + TP_ARGS(struct lttng_session *, session, void *, baddr, const char*,
> sopath, int64_t, size, int64_t, mtime),
> + TP_FIELDS(
> + ctf_integer_hex(void *, baddr, baddr)
> + ctf_string(sopath, sopath)
> + ctf_integer(int64_t, size, size)
> + ctf_integer(int64_t, mtime, mtime)
> + )
> +)
> +
> +#endif /* _TRACEPOINT_UST_BADDR_STATEDUMP_H */
> +
> +#undef TRACEPOINT_INCLUDE
> +#define TRACEPOINT_INCLUDE "./ust_baddr_statedump.h"
> +
> +/* This part must be outside ifdef protection */
> +#include <lttng/tracepoint-event.h>
> +
> +#ifdef __cplusplus
> +}
> +#endif
> diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
> index 26601a6..65ae320 100644
> --- a/liblttng-ust/lttng-events.c
> +++ b/liblttng-ust/lttng-events.c
> @@ -86,6 +86,8 @@ void lttng_session_sync_enablers(struct lttng_session
> *session);
> static
> void lttng_enabler_destroy(struct lttng_enabler *enabler);
>
> +void _lttng_ust_sockinfo_session_enabled(struct lttng_session
> *session_enabled);
> +
> /*
> * Called with ust lock held.
> */
> @@ -293,6 +295,8 @@ int lttng_session_enable(struct lttng_session *session)
> /* Set atomically the state to "active" */
> CMM_ACCESS_ONCE(session->active) = 1;
> CMM_ACCESS_ONCE(session->been_active) = 1;
> +
> + _lttng_ust_sockinfo_session_enabled(session);
> end:
> return ret;
> }
> diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
> index a6e4ba3..3968804 100644
> --- a/liblttng-ust/lttng-ust-comm.c
> +++ b/liblttng-ust/lttng-ust-comm.c
> @@ -34,6 +34,7 @@
> #include <time.h>
> #include <assert.h>
> #include <signal.h>
> +#include <dlfcn.h>
> #include <urcu/uatomic.h>
> #include <urcu/futex.h>
> #include <urcu/compiler.h>
> @@ -106,6 +107,7 @@ struct sock_info {
>
> char wait_shm_path[PATH_MAX];
> char *wait_shm_mmap;
> + struct lttng_session *session_enabled;
OK
> };
>
> /* Socket from app (connect) to session daemon (listen) for communication */
> @@ -122,6 +124,8 @@ struct sock_info global_apps = {
> .notify_socket = -1,
>
> .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
> +
> + .session_enabled = NULL,
If have this NULL field spelled out (not strictly needed, but I understand that we're already putting them = 0 for other fields) for global_apps, we also need it for local_apps (just below).
> };
>
> /* TODO: allow global_apps_sock_path override */
> @@ -176,6 +180,7 @@ static const char *cmd_name_mapping[] = {
>
> static const char *str_timeout;
> static int got_timeout_env;
> +static void *ust_baddr_handle;
>
> extern void lttng_ring_buffer_client_overwrite_init(void);
> extern void lttng_ring_buffer_client_overwrite_rt_init(void);
> @@ -235,6 +240,51 @@ void print_cmd(int cmd, int handle)
> }
>
> static
> +void *lttng_ust_baddr_handle(void)
> +{
> + if (!ust_baddr_handle) {
> + ust_baddr_handle = dlopen(
> + "liblttng-ust-baddr.so.0", RTLD_NOW | RTLD_GLOBAL);
> + if (ust_baddr_handle == NULL)
> + ERR("%s", dlerror());
> + }
> + return ust_baddr_handle;
> +}
> +
> +static void __attribute__((destructor))
> +lttng_ust_baddr_handle_fini(void);
> +static void
> +lttng_ust_baddr_handle_fini(void)
> +{
> + if (ust_baddr_handle) {
> + int ret = dlclose(ust_baddr_handle);
> + if (ret)
> + ERR("%s", dlerror());
> + }
> +}
Rather than adding another destructor to the same file (which can be executed in any order wrt other destructors), could you instead make lttng_ust_exit() call this teardown function ?
> +
> +static
> +int lttng_ust_baddr_statedump(struct lttng_session *session)
> +{
> + static
> + int (*lttng_ust_baddr_init_fn)(struct lttng_session *);
> +
> + if (!lttng_ust_baddr_init_fn) {
> + void *baddr_handle = lttng_ust_baddr_handle();
> + if (baddr_handle) {
> + lttng_ust_baddr_init_fn = dlsym(baddr_handle,
> + "baddr_statedump");
> + if (lttng_ust_baddr_init_fn == NULL)
> + ERR("%s", dlerror());
> + }
> + if (!lttng_ust_baddr_init_fn)
> + return -1;
> + }
> +
> + return lttng_ust_baddr_init_fn(session);
> +}
> +
> +static
> int setup_local_apps(void)
> {
> const char *home_dir;
> @@ -1143,6 +1193,13 @@ restart:
> ret = handle_message(sock_info, sock, &lum);
> if (ret) {
> ERR("Error handling message for %s socket", sock_info->name);
> + } else {
> + struct lttng_session *session =
> + global_apps.session_enabled;
This does not handle local_apps (per-user sessiond).
What you want here is e.g.:
struct lttng_session *session = sock_info->session_enabled;
> + if (session) {
sock_info->session_enabled = NULL;
lttng_ust_baddr_statedump(session);
> + global_apps.session_enabled = NULL;
> + lttng_ust_baddr_statedump(session);
> + }
> }
> continue;
> default:
> @@ -1456,3 +1513,8 @@ void ust_after_fork_child(sigset_t *restore_sigset)
> ust_after_fork_common(restore_sigset);
> lttng_ust_init();
> }
> +
> +void _lttng_ust_sockinfo_session_enabled(struct lttng_session
> *session_enabled)
> +{
> + global_apps.session_enabled = session_enabled;
> +}
void _lttng_ust_sockinfo_session_enabled(struct sock_info *sock_info, struct lttng_session *session_enabled)
{
sock_info->session_enabled = session_enabled;
}
Thanks,
Mathieu
> --
> 1.8.4.2
>
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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