From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Wed, 13 Nov 2013 13:48:30 +0000 (UTC) Subject: [lttng-dev] [PATCH 2/2] Implement base-address-state tracing In-Reply-To: <1384183688-19038-3-git-send-email-paul_woegerer@mentor.com> References: <1384183688-19038-1-git-send-email-paul_woegerer@mentor.com> <1384183688-19038-3-git-send-email-paul_woegerer@mentor.com> Message-ID: <1564035182.66247.1384350510440.JavaMail.zimbra@efficios.com> ----- Original Message ----- > From: "Paul Woegerer" > To: lttng-dev at lists.lttng.org, "mathieu desnoyers" > Sent: Monday, November 11, 2013 10:28:08 AM > Subject: [PATCH 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 > --- > include/lttng/ust-tracepoint-event.h | 14 ++++++++ > liblttng-ust-baddr/Makefile.am | 4 ++- > liblttng-ust-baddr/lttng-ust-baddr.c | 47 +++++++++++++++++++++++++ > liblttng-ust-baddr/ust_baddr_statedump.c | 21 +++++++++++ > liblttng-ust-baddr/ust_baddr_statedump.h | 60 > ++++++++++++++++++++++++++++++++ > liblttng-ust/lttng-events.c | 10 ++++++ > liblttng-ust/lttng-tracer-core.h | 2 ++ > liblttng-ust/lttng-ust-comm.c | 52 +++++++++++++++++++++++++++ > 8 files changed, 209 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..92b5cca 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 +63,49 @@ pop_baddr(void *so_base) > tracepoint(ust_baddr, pop, so_base); > return 0; > } > + > +static int > +_dl_iterate_write_memregion(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++) { > + if (info->dlpi_phdr[j].p_type == PT_LOAD) { if (info->dlpi_phdr[j].p_type != PT_LOAD) continue; will save us one indentation level. > + char resolved_path[PATH_MAX]; > + struct stat sostat; > + void *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) { > + 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 if (!realpath(info->dlpi_name, resolved_path)) > + snprintf(resolved_path, PATH_MAX - 1, "[%s]", > + info->dlpi_name); We have if and else if. What about the else ? We tend to leave at least a comment in these cases, just in case it is forgotten. > + > + 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); > + break; Why are we breaking after the first object's loaded ELF segment ? > + } > + } > + return 0; > +} > + Adding a comment that explains in human readable text what this function is doing would be useful here. > +int > +baddr_statedump(struct lttng_session *session) > +{ > + dl_iterate_phdr(_dl_iterate_write_memregion, 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 > + * > + * 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 > + * > + * 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 > +#include > +#include > + > +#define LTTNG_UST_BADDR_STATEDUMP_PROVIDER > +#include > + > +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 > + > +#ifdef __cplusplus > +} > +#endif > diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c > index 26601a6..814549e 100644 > --- a/liblttng-ust/lttng-events.c > +++ b/liblttng-ust/lttng-events.c > @@ -86,6 +86,14 @@ void lttng_session_sync_enablers(struct lttng_session > *session); > static > void lttng_enabler_destroy(struct lttng_enabler *enabler); > > +static struct lttng_session *_lttng_session_enabled_transition; > +struct lttng_session *lttng_session_enabled_transition(void) Not sure I like the fct vs data naming that only differs from a single underscore. Locking is also not documented here. How about we move this pointer into struct sock_info ? It would therefore be associated with either the "per-user" or "global" sessiond, and therefore we'd have an easier time synchronizing it. There is no actual reason why it should need the ust_lock(). the struct lttng_session "owner" pointer can be casted to a struct sock_info (e.g. lttng_get_notify_socket). You can implement the "getter" function in lttng-ust-comm.c that takes the void *owner as parameter. Thanks, Mathieu > +{ > + struct lttng_session *ret = _lttng_session_enabled_transition; > + _lttng_session_enabled_transition = NULL; > + return ret; > +} > + > /* > * Called with ust lock held. > */ > @@ -293,6 +301,8 @@ 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_session_enabled_transition = session; > end: > return ret; > } > diff --git a/liblttng-ust/lttng-tracer-core.h > b/liblttng-ust/lttng-tracer-core.h > index f643a7e..f77ebaf 100644 > --- a/liblttng-ust/lttng-tracer-core.h > +++ b/liblttng-ust/lttng-tracer-core.h > @@ -45,4 +45,6 @@ const char *lttng_ust_obj_get_name(int id); > > int lttng_get_notify_socket(void *owner); > > +struct lttng_session *lttng_session_enabled_transition(void); > + > #endif /* _LTTNG_TRACER_CORE_H */ > diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c > index a6e4ba3..a0f1b42 100644 > --- a/liblttng-ust/lttng-ust-comm.c > +++ b/liblttng-ust/lttng-ust-comm.c > @@ -43,6 +43,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -176,6 +177,7 @@ 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 +237,51 @@ void print_cmd(int cmd, int handle) > } > > static > +void *lttng_ust_baddr_handle(void) > +{ > + if (!ust_baddr_handle) { > + ust_baddr_handle = lttng_ust_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 = lttng_ust_dlclose(ust_baddr_handle); > + if (ret) > + ERR("%s", dlerror()); > + } > +} > + > +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 +1190,11 @@ 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 = > + lttng_session_enabled_transition(); > + if (session) > + lttng_ust_baddr_statedump(session); > } > continue; > default: > -- > 1.8.4.2 > > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com