[lttng-dev] [RFC PATCH lttng-ust 1/2] Add library load/unload tracking events
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Mon Jul 4 22:53:47 UTC 2016
Track library load and unload, with the following new events:
lttng_ust_lib:load
lttng_ust_lib:build_id
lttng_ust_lib:debug_link
lttng_ust_lib:unload
This takes care of correctly tracing the mapping of direct dependencies
of dlopen'd libraries, which was not appropriately done by tracing just
dlopen events.
Fixes: #1035
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
---
include/lttng/ust-events.h | 2 +
liblttng-ust-dl/lttng-ust-dl.c | 15 +-
liblttng-ust/Makefile.am | 2 +
liblttng-ust/lttng-ust-elf.c | 1 +
liblttng-ust/lttng-ust-statedump.c | 395 +++++++++++++++++++++++++++++++------
5 files changed, 350 insertions(+), 65 deletions(-)
diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index 9f6aa06..309206d 100644
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -722,6 +722,8 @@ struct cds_list_head *_lttng_get_sessions(void);
struct lttng_enum *lttng_ust_enum_get(struct lttng_session *session,
const char *enum_name);
+void lttng_ust_dl_update(void *ip);
+
/* For backward compatibility. Leave those exported symbols in place. */
extern struct lttng_ctx *lttng_static_ctx;
void lttng_context_init(void);
diff --git a/liblttng-ust-dl/lttng-ust-dl.c b/liblttng-ust-dl/lttng-ust-dl.c
index e457e7a..81b5bec 100644
--- a/liblttng-ust-dl/lttng-ust-dl.c
+++ b/liblttng-ust-dl/lttng-ust-dl.c
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2013 Paul Woegerer <paul.woegerer at mentor.com>
* Copyright (C) 2015 Antoine Busque <abusque at efficios.com>
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -26,6 +27,7 @@
#include <lttng/ust-dlfcn.h>
#include <lttng/ust-elf.h>
+#include <lttng/ust-events.h>
#include <helper.h>
#include "usterr-signal-safe.h"
@@ -135,19 +137,21 @@ void *dlopen(const char *filename, int flag)
ret = dlinfo(handle, RTLD_DI_LINKMAP, &p);
if (ret != -1 && p != NULL && p->l_addr != 0) {
- lttng_ust_dl_dlopen((void *) p->l_addr, p->l_name,
+ lttng_ust_dl_dlopen((void *) p->l_addr,
+ p->l_name,
LTTNG_UST_CALLER_IP());
}
}
-
+ lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
return handle;
}
int dlclose(void *handle)
{
+ int ret;
+
if (__tracepoint_ptrs_registered) {
struct link_map *p = NULL;
- int ret;
ret = dlinfo(handle, RTLD_DI_LINKMAP, &p);
if (ret != -1 && p != NULL && p->l_addr != 0) {
@@ -156,6 +160,7 @@ int dlclose(void *handle)
(void *) p->l_addr);
}
}
-
- return _lttng_ust_dl_libc_dlclose(handle);
+ ret = _lttng_ust_dl_libc_dlclose(handle);
+ lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
+ return ret;
}
diff --git a/liblttng-ust/Makefile.am b/liblttng-ust/Makefile.am
index 05929be..a2a32b4 100644
--- a/liblttng-ust/Makefile.am
+++ b/liblttng-ust/Makefile.am
@@ -43,6 +43,8 @@ liblttng_ust_runtime_la_SOURCES = \
lttng-ust-statedump.c \
lttng-ust-statedump.h \
lttng-ust-statedump-provider.h \
+ ust_lib.c \
+ ust_lib.h \
tracepoint-internal.h \
clock.h \
compat.h \
diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c
index 5f27920..e5b8a08 100644
--- a/liblttng-ust/lttng-ust-elf.c
+++ b/liblttng-ust/lttng-ust-elf.c
@@ -25,6 +25,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
+#include <stdbool.h>
#include "lttng-tracer-core.h"
#define BUF_LEN 4096
diff --git a/liblttng-ust/lttng-ust-statedump.c b/liblttng-ust/lttng-ust-statedump.c
index bcb168b..c8e508c 100644
--- a/liblttng-ust/lttng-ust-statedump.c
+++ b/liblttng-ust/lttng-ust-statedump.c
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2013 Paul Woegerer <paul_woegerer at mentor.com>
* Copyright (C) 2015 Antoine Busque <abusque at efficios.com>
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -24,27 +25,32 @@
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
+#include <stdbool.h>
#include <sys/types.h>
#include <unistd.h>
#include <lttng/ust-elf.h>
+#include <helper.h>
#include "lttng-tracer-core.h"
#include "lttng-ust-statedump.h"
+#include "jhash.h"
#define TRACEPOINT_DEFINE
+#include "ust_lib.h" /* Only define. */
+
#define TRACEPOINT_CREATE_PROBES
#define TP_SESSION_CHECK
-#include "lttng-ust-statedump-provider.h"
+#include "lttng-ust-statedump-provider.h" /* Define and create probes. */
struct dl_iterate_data {
- void *owner;
int exec_found;
+ bool first;
+ bool cancel;
};
struct bin_info_data {
- void *owner;
void *base_addr_ptr;
- const char *resolved_path;
+ char resolved_path[PATH_MAX];
char *dbg_file;
uint8_t *build_id;
uint64_t memsz;
@@ -56,14 +62,143 @@ struct bin_info_data {
uint8_t has_debug_link;
};
+struct lttng_ust_dl_node {
+ struct bin_info_data bin_data;
+ struct cds_hlist_node node;
+ bool traced;
+ bool marked;
+};
+
+#define UST_DL_STATE_HASH_BITS 8
+#define UST_DL_STATE_TABLE_SIZE (1 << UST_DL_STATE_HASH_BITS)
+struct cds_hlist_head dl_state_table[UST_DL_STATE_TABLE_SIZE];
+
typedef void (*tracepoint_cb)(struct lttng_session *session, void *priv);
+static
+struct lttng_ust_dl_node *alloc_dl_node(const struct bin_info_data *bin_data)
+{
+ struct lttng_ust_dl_node *e;
+
+ e = zmalloc(sizeof(struct lttng_ust_dl_node));
+ if (!e)
+ return NULL;
+ if (bin_data->dbg_file) {
+ e->bin_data.dbg_file = strdup(bin_data->dbg_file);
+ if (!e->bin_data.dbg_file)
+ goto error;
+ }
+ if (bin_data->build_id) {
+ e->bin_data.build_id = zmalloc(bin_data->build_id_len);
+ if (!e->bin_data.build_id)
+ goto error;
+ memcpy(e->bin_data.build_id, bin_data->build_id,
+ bin_data->build_id_len);
+ }
+ e->bin_data.base_addr_ptr = bin_data->base_addr_ptr;
+ memcpy(e->bin_data.resolved_path, bin_data->resolved_path, PATH_MAX);
+ e->bin_data.memsz = bin_data->memsz;
+ e->bin_data.build_id_len = bin_data->build_id_len;
+ e->bin_data.vdso = bin_data->vdso;
+ e->bin_data.crc = bin_data->crc;
+ e->bin_data.is_pic = bin_data->is_pic;
+ e->bin_data.has_build_id = bin_data->has_build_id;
+ e->bin_data.has_debug_link = bin_data->has_debug_link;
+ return e;
+
+error:
+ free(e->bin_data.build_id);
+ free(e->bin_data.dbg_file);
+ free(e);
+ return NULL;
+}
+
+static
+void free_dl_node(struct lttng_ust_dl_node *e)
+{
+ free(e->bin_data.build_id);
+ free(e->bin_data.dbg_file);
+ free(e);
+}
+
+/* Return 0 if same, nonzero if not. */
+static
+int compare_bin_data(const struct bin_info_data *a,
+ const struct bin_info_data *b)
+{
+ if (a->base_addr_ptr != b->base_addr_ptr)
+ return -1;
+ if (strcmp(a->resolved_path, b->resolved_path) != 0)
+ return -1;
+ if (a->dbg_file && !b->dbg_file)
+ return -1;
+ if (!a->dbg_file && b->dbg_file)
+ return -1;
+ if (a->dbg_file && strcmp(a->dbg_file, b->dbg_file) != 0)
+ return -1;
+ if (a->build_id && !b->build_id)
+ return -1;
+ if (!a->build_id && b->build_id)
+ return -1;
+ if (a->build_id_len != b->build_id_len)
+ return -1;
+ if (a->build_id &&
+ memcmp(a->build_id, b->build_id, a->build_id_len) != 0)
+ return -1;
+ if (a->memsz != b->memsz)
+ return -1;
+ if (a->vdso != b->vdso)
+ return -1;
+ if (a->crc != b->crc)
+ return -1;
+ if (a->is_pic != b->is_pic)
+ return -1;
+ if (a->has_build_id != b->has_build_id)
+ return -1;
+ if (a->has_debug_link != b->has_debug_link)
+ return -1;
+ return 0;
+}
+
+static
+struct lttng_ust_dl_node *find_or_create_dl_node(struct bin_info_data *bin_data)
+{
+ struct cds_hlist_head *head;
+ struct lttng_ust_dl_node *e;
+ unsigned int hash;
+ bool found = false;
+
+ hash = jhash(&bin_data->base_addr_ptr,
+ sizeof(bin_data->base_addr_ptr), 0);
+ head = &dl_state_table[hash & (UST_DL_STATE_TABLE_SIZE - 1)];
+ cds_hlist_for_each_entry_2(e, head, node) {
+ if (compare_bin_data(&e->bin_data, bin_data) != 0)
+ continue;
+ found = true;
+ break;
+ }
+ if (!found) {
+ /* Create */
+ e = alloc_dl_node(bin_data);
+ if (!e)
+ return NULL;
+ cds_hlist_add_head(&e->node, head);
+ }
+ return e;
+}
+
+static
+void remove_dl_node(struct lttng_ust_dl_node *e)
+{
+ cds_hlist_del(&e->node);
+}
+
/*
* Trace statedump event into all sessions owned by the caller thread
* for which statedump is pending.
*/
static
-int trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv)
+void trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv)
{
struct cds_list_head *sessionsp;
struct lttng_session *session;
@@ -76,7 +211,6 @@ int trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv)
continue;
tp_cb(session, priv);
}
- return 0;
}
static
@@ -165,9 +299,22 @@ end:
}
static
-int trace_baddr(struct bin_info_data *bin_data)
+void trace_baddr(struct bin_info_data *bin_data, void *owner)
+{
+ trace_statedump_event(trace_bin_info_cb, owner, bin_data);
+
+ if (bin_data->has_build_id)
+ trace_statedump_event(trace_build_id_cb, owner, bin_data);
+
+ if (bin_data->has_debug_link)
+ trace_statedump_event(trace_debug_link_cb, owner, bin_data);
+}
+
+static
+int extract_baddr(struct bin_info_data *bin_data)
{
int ret = 0;
+ struct lttng_ust_dl_node *e;
if (!bin_data->vdso) {
ret = get_elf_info(bin_data);
@@ -180,73 +327,146 @@ int trace_baddr(struct bin_info_data *bin_data)
bin_data->has_debug_link = 0;
}
- ret = trace_statedump_event(trace_bin_info_cb, bin_data->owner,
- bin_data);
- if (ret) {
+ e = find_or_create_dl_node(bin_data);
+ if (!e) {
+ ret = -1;
goto end;
}
-
- if (bin_data->has_build_id) {
- ret = trace_statedump_event(
- trace_build_id_cb, bin_data->owner, bin_data);
- free(bin_data->build_id);
- if (ret) {
- goto end;
- }
- }
-
- if (bin_data->has_debug_link) {
- ret = trace_statedump_event(
- trace_debug_link_cb, bin_data->owner, bin_data);
- free(bin_data->dbg_file);
- if (ret) {
- goto end;
- }
- }
-
+ e->marked = true;
end:
+ free(bin_data->build_id);
+ bin_data->build_id = NULL;
+ free(bin_data->dbg_file);
+ bin_data->dbg_file = NULL;
return ret;
}
static
-int trace_statedump_start(void *owner)
+void trace_statedump_start(void *owner)
{
- return trace_statedump_event(trace_start_cb, owner, NULL);
+ trace_statedump_event(trace_start_cb, owner, NULL);
}
static
-int trace_statedump_end(void *owner)
+void trace_statedump_end(void *owner)
{
- return trace_statedump_event(trace_end_cb, owner, NULL);
+ trace_statedump_event(trace_end_cb, owner, NULL);
}
static
-int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data)
+void iter_begin(struct dl_iterate_data *data)
{
- int j, ret = 0;
- struct dl_iterate_data *data = _data;
+ unsigned int i;
/*
* UST lock nests within dynamic loader lock.
*
- * Hold this lock across handling of the entire module to
+ * Hold this lock across handling of the module listing to
* protect memory allocation at early process start, due to
* interactions with libc-wrapper lttng malloc instrumentation.
*/
if (ust_lock()) {
- goto end;
+ data->cancel = true;
+ return;
}
+ /* Ensure all entries are unmarked. */
+ for (i = 0; i < UST_DL_STATE_TABLE_SIZE; i++) {
+ struct cds_hlist_head *head;
+ struct lttng_ust_dl_node *e;
+
+ head = &dl_state_table[i];
+ cds_hlist_for_each_entry_2(e, head, node)
+ assert(!e->marked);
+ }
+}
+
+static
+void trace_lib_load(const struct bin_info_data *bin_data, void *ip)
+{
+ tracepoint(lttng_ust_lib, load,
+ ip, bin_data->base_addr_ptr, bin_data->resolved_path,
+ bin_data->memsz, bin_data->has_build_id,
+ bin_data->has_debug_link);
+
+ if (bin_data->has_build_id) {
+ tracepoint(lttng_ust_lib, build_id,
+ ip, bin_data->base_addr_ptr, bin_data->build_id,
+ bin_data->build_id_len);
+ }
+
+ if (bin_data->has_debug_link) {
+ tracepoint(lttng_ust_lib, debug_link,
+ ip, bin_data->base_addr_ptr, bin_data->dbg_file,
+ bin_data->crc);
+ }
+}
+
+static
+void trace_lib_unload(const struct bin_info_data *bin_data, void *ip)
+{
+ tracepoint(lttng_ust_lib, unload, ip, bin_data->base_addr_ptr);
+}
+
+static
+void iter_end(struct dl_iterate_data *data, void *ip)
+{
+ unsigned int i;
+
+ /*
+ * Iterate on hash table.
+ * For each marked, traced, do nothing.
+ * For each marked, not traced, trace lib open event. traced = true.
+ * For each unmarked, traced, trace lib close event. remove node.
+ * For each unmarked, not traced, remove node.
+ */
+ for (i = 0; i < UST_DL_STATE_TABLE_SIZE; i++) {
+ struct cds_hlist_head *head;
+ struct lttng_ust_dl_node *e;
+
+ head = &dl_state_table[i];
+ cds_hlist_for_each_entry_2(e, head, node) {
+ if (e->marked) {
+ if (!e->traced) {
+ trace_lib_load(&e->bin_data, ip);
+ e->traced = true;
+ }
+ } else {
+ if (e->traced)
+ trace_lib_unload(&e->bin_data, ip);
+ remove_dl_node(e);
+ free_dl_node(e);
+ }
+ e->marked = false;
+ }
+ }
+ ust_unlock();
+}
+
+static
+int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data)
+{
+ int j, ret = 0;
+ struct dl_iterate_data *data = _data;
+
+ if (data->first) {
+ iter_begin(data);
+ data->first = false;
+ }
+
+ if (data->cancel)
+ goto end;
+
for (j = 0; j < info->dlpi_phnum; j++) {
struct bin_info_data bin_data;
- char resolved_path[PATH_MAX];
- void *base_addr_ptr;
if (info->dlpi_phdr[j].p_type != PT_LOAD)
continue;
+ memset(&bin_data, 0, sizeof(bin_data));
+
/* Calculate virtual memory address of the loadable segment */
- base_addr_ptr = (void *) info->dlpi_addr +
+ bin_data.base_addr_ptr = (void *) info->dlpi_addr +
info->dlpi_phdr[j].p_vaddr;
if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0)) {
@@ -264,15 +484,16 @@ int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data)
* executable's full path.
*/
path_len = readlink("/proc/self/exe",
- resolved_path,
+ bin_data.resolved_path,
PATH_MAX - 1);
if (path_len <= 0)
break;
- resolved_path[path_len] = '\0';
+ bin_data.resolved_path[path_len] = '\0';
bin_data.vdso = 0;
} else {
- snprintf(resolved_path, PATH_MAX - 1, "[vdso]");
+ snprintf(bin_data.resolved_path,
+ PATH_MAX - 1, "[vdso]");
bin_data.vdso = 1;
}
} else {
@@ -281,8 +502,10 @@ int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data)
* the path to the binary really exists. If not,
* treat as vdso and use dlpi_name as 'path'.
*/
- if (!realpath(info->dlpi_name, resolved_path)) {
- snprintf(resolved_path, PATH_MAX - 1, "[%s]",
+ if (!realpath(info->dlpi_name,
+ bin_data.resolved_path)) {
+ snprintf(bin_data.resolved_path,
+ PATH_MAX - 1, "[%s]",
info->dlpi_name);
bin_data.vdso = 1;
} else {
@@ -290,39 +513,73 @@ int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data)
}
}
- bin_data.owner = data->owner;
- bin_data.base_addr_ptr = base_addr_ptr;
- bin_data.resolved_path = resolved_path;
- ret = trace_baddr(&bin_data);
+ ret = extract_baddr(&bin_data);
break;
}
end:
- ust_unlock();
return ret;
}
-/*
- * Generate a statedump of base addresses of all shared objects loaded
- * by the traced application, as well as for the application's
- * executable itself.
- */
static
-int do_baddr_statedump(void *owner)
+void ust_dl_table_statedump(void *owner)
+{
+ unsigned int i;
+
+ if (ust_lock())
+ goto end;
+
+ /* Statedump each traced table entry into session for owner. */
+ for (i = 0; i < UST_DL_STATE_TABLE_SIZE; i++) {
+ struct cds_hlist_head *head;
+ struct lttng_ust_dl_node *e;
+
+ head = &dl_state_table[i];
+ cds_hlist_for_each_entry_2(e, head, node) {
+ if (e->traced)
+ trace_baddr(&e->bin_data, owner);
+ }
+ }
+
+end:
+ ust_unlock();
+}
+
+void lttng_ust_dl_update(void *ip)
{
struct dl_iterate_data data;
if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP"))
- return 0;
+ return;
- data.owner = owner;
data.exec_found = 0;
+ data.first = true;
+ data.cancel = false;
/*
* Iterate through the list of currently loaded shared objects and
- * generate events for loadable segments using
+ * generate tables entries for loadable segments using
* extract_bin_info_events.
+ * Removed libraries are detected by mark-and-sweep: marking is
+ * done in the iteration over libraries, and sweeping is
+ * performed by iter_end().
*/
dl_iterate_phdr(extract_bin_info_events, &data);
+ if (data.first)
+ iter_begin(&data);
+ iter_end(&data, ip);
+}
+/*
+ * Generate a statedump of base addresses of all shared objects loaded
+ * by the traced application, as well as for the application's
+ * executable itself.
+ */
+static
+int do_baddr_statedump(void *owner)
+{
+ if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP"))
+ return 0;
+ lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
+ ust_dl_table_statedump(owner);
return 0;
}
@@ -348,6 +605,23 @@ void lttng_ust_statedump_init(void)
__tracepoints__init();
__tracepoints__ptrs_init();
__lttng_events_init__lttng_ust_statedump();
+ lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
+}
+
+static
+void ust_dl_state_destroy(void)
+{
+ unsigned int i;
+
+ for (i = 0; i < UST_DL_STATE_TABLE_SIZE; i++) {
+ struct cds_hlist_head *head;
+ struct lttng_ust_dl_node *e, *tmp;
+
+ head = &dl_state_table[i];
+ cds_hlist_for_each_entry_safe_2(e, tmp, head, node)
+ free_dl_node(e);
+ CDS_INIT_HLIST_HEAD(head);
+ }
}
void lttng_ust_statedump_destroy(void)
@@ -355,4 +629,5 @@ void lttng_ust_statedump_destroy(void)
__lttng_events_exit__lttng_ust_statedump();
__tracepoints__ptrs_destroy();
__tracepoints__destroy();
+ ust_dl_state_destroy();
}
--
2.1.4
More information about the lttng-dev
mailing list