liblttng-ust-dl/lttng-ust-dl.c

   1 /*
   2  * Copyright (C) 2013  Paul Woegerer <paul.woegerer@mentor.com>
   3  * Copyright (C) 2015  Antoine Busque <abusque@efficios.com>
   4  * Copyright (C) 2016  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; version 2.1 of
   9  * the License.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #define _LGPL_SOURCE
  22 #include <limits.h>
  23 #include <stdio.h>
  24 #include <stdint.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27
  28 #include <lttng/ust-dlfcn.h>
  29 #include <lttng/ust-elf.h>
  30 #include <lttng/ust-events.h>
  31 #include <helper.h>
  32 #include "usterr-signal-safe.h"
  33
  34 /* Include link.h last else it conflicts with ust-dlfcn. */
  35 #include <link.h>
  36
  37 #define TRACEPOINT_DEFINE
  38 #include "ust_dl.h"
  39
  40 static void *(*__lttng_ust_plibc_dlopen)(const char *filename, int flags);
  41 #ifdef HAVE_DLMOPEN
  42 static void *(*__lttng_ust_plibc_dlmopen)(Lmid_t nsid, const char *filename,
  43                 int flags);
  44 #endif
  45 static int (*__lttng_ust_plibc_dlclose)(void *handle);
  46
  47 static
  48 void *_lttng_ust_dl_libc_dlopen(const char *filename, int flags)
  49 {
  50         if (!__lttng_ust_plibc_dlopen) {
  51                 __lttng_ust_plibc_dlopen = dlsym(RTLD_NEXT, "dlopen");
  52                 if (!__lttng_ust_plibc_dlopen) {
  53                         fprintf(stderr, "%s\n", dlerror());
  54                         return NULL;
  55                 }
  56         }
  57         return __lttng_ust_plibc_dlopen(filename, flags);
  58 }
  59
  60 #ifdef HAVE_DLMOPEN
  61 static
  62 void *_lttng_ust_dl_libc_dlmopen(Lmid_t nsid, const char *filename,
  63                 int flags)
  64 {
  65         if (!__lttng_ust_plibc_dlmopen) {
  66                 __lttng_ust_plibc_dlmopen = dlsym(RTLD_NEXT, "dlmopen");
  67                 if (!__lttng_ust_plibc_dlmopen) {
  68                         fprintf(stderr, "%s\n", dlerror());
  69                         return NULL;
  70                 }
  71         }
  72         return __lttng_ust_plibc_dlmopen(nsid, filename, flags);
  73 }
  74 #endif
  75
  76 static
  77 int _lttng_ust_dl_libc_dlclose(void *handle)
  78 {
  79         if (!__lttng_ust_plibc_dlclose) {
  80                 __lttng_ust_plibc_dlclose = dlsym(RTLD_NEXT, "dlclose");
  81                 if (!__lttng_ust_plibc_dlclose) {
  82                         fprintf(stderr, "%s\n", dlerror());
  83                         return -1;
  84                 }
  85         }
  86         return __lttng_ust_plibc_dlclose(handle);
  87 }
  88
  89 static
  90 void lttng_ust_dl_dlopen(void *so_base, const char *so_name,
  91                 int flags, void *ip)
  92 {
  93         char resolved_path[PATH_MAX];
  94         struct lttng_ust_elf *elf;
  95         uint64_t memsz;
  96         uint8_t *build_id = NULL;
  97         size_t build_id_len;
  98         char *dbg_file = NULL;
  99         uint32_t crc;
 100         int has_build_id = 0, has_debug_link = 0;
 101         int ret;
 102
 103         if (!realpath(so_name, resolved_path)) {
 104                 ERR("could not resolve path '%s'", so_name);
 105                 return;
 106         }
 107
 108         elf = lttng_ust_elf_create(resolved_path);
 109         if (!elf) {
 110                 ERR("could not access file %s", resolved_path);
 111                 return;
 112         }
 113
 114         ret = lttng_ust_elf_get_memsz(elf, &memsz);
 115         if (ret) {
 116                 goto end;
 117         }
 118         ret = lttng_ust_elf_get_build_id(
 119                 elf, &build_id, &build_id_len, &has_build_id);
 120         if (ret) {
 121                 goto end;
 122         }
 123         ret = lttng_ust_elf_get_debug_link(
 124                 elf, &dbg_file, &crc, &has_debug_link);
 125         if (ret) {
 126                 goto end;
 127         }
 128
 129         tracepoint(lttng_ust_dl, dlopen,
 130                 ip, so_base, resolved_path, flags, memsz,
 131                 has_build_id, has_debug_link);
 132
 133         if (has_build_id) {
 134                 tracepoint(lttng_ust_dl, build_id,
 135                         ip, so_base, build_id, build_id_len);
 136         }
 137
 138         if (has_debug_link) {
 139                 tracepoint(lttng_ust_dl, debug_link,
 140                         ip, so_base, dbg_file, crc);
 141         }
 142
 143 end:
 144         free(dbg_file);
 145         free(build_id);
 146         lttng_ust_elf_destroy(elf);
 147         return;
 148 }
 149
 150 #ifdef HAVE_DLMOPEN
 151 static
 152 void lttng_ust_dl_dlmopen(void *so_base, Lmid_t nsid, const char *so_name,
 153                 int flags, void *ip)
 154 {
 155         char resolved_path[PATH_MAX];
 156         struct lttng_ust_elf *elf;
 157         uint64_t memsz;
 158         uint8_t *build_id = NULL;
 159         size_t build_id_len;
 160         char *dbg_file = NULL;
 161         uint32_t crc;
 162         int has_build_id = 0, has_debug_link = 0;
 163         int ret;
 164
 165         if (!realpath(so_name, resolved_path)) {
 166                 ERR("could not resolve path '%s'", so_name);
 167                 return;
 168         }
 169
 170         elf = lttng_ust_elf_create(resolved_path);
 171         if (!elf) {
 172                 ERR("could not access file %s", resolved_path);
 173                 return;
 174         }
 175
 176         ret = lttng_ust_elf_get_memsz(elf, &memsz);
 177         if (ret) {
 178                 goto end;
 179         }
 180         ret = lttng_ust_elf_get_build_id(
 181                 elf, &build_id, &build_id_len, &has_build_id);
 182         if (ret) {
 183                 goto end;
 184         }
 185         ret = lttng_ust_elf_get_debug_link(
 186                 elf, &dbg_file, &crc, &has_debug_link);
 187         if (ret) {
 188                 goto end;
 189         }
 190
 191         tracepoint(lttng_ust_dl, dlmopen,
 192                 ip, so_base, nsid, resolved_path, flags, memsz,
 193                 has_build_id, has_debug_link);
 194
 195         if (has_build_id) {
 196                 tracepoint(lttng_ust_dl, build_id,
 197                         ip, so_base, build_id, build_id_len);
 198         }
 199
 200         if (has_debug_link) {
 201                 tracepoint(lttng_ust_dl, debug_link,
 202                         ip, so_base, dbg_file, crc);
 203         }
 204
 205 end:
 206         free(dbg_file);
 207         free(build_id);
 208         lttng_ust_elf_destroy(elf);
 209         return;
 210 }
 211 #endif
 212
 213 void *dlopen(const char *filename, int flags)
 214 {
 215         void *handle;
 216
 217         handle = _lttng_ust_dl_libc_dlopen(filename, flags);
 218         if (__tracepoint_ptrs_registered && handle) {
 219                 struct link_map *p = NULL;
 220                 int ret;
 221
 222                 ret = dlinfo(handle, RTLD_DI_LINKMAP, &p);
 223                 if (ret != -1 && p != NULL && p->l_addr != 0) {
 224                         lttng_ust_dl_dlopen((void *) p->l_addr,
 225                                 p->l_name, flags, LTTNG_UST_CALLER_IP());
 226                 }
 227         }
 228         lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
 229         return handle;
 230 }
 231
 232 #ifdef HAVE_DLMOPEN
 233 void *dlmopen(Lmid_t nsid, const char *filename, int flags)
 234 {
 235         void *handle;
 236
 237         handle = _lttng_ust_dl_libc_dlmopen(nsid, filename, flags);
 238         if (__tracepoint_ptrs_registered && handle) {
 239                 struct link_map *p = NULL;
 240                 int ret;
 241
 242                 ret = dlinfo(handle, RTLD_DI_LINKMAP, &p);
 243                 if (ret != -1 && p != NULL && p->l_addr != 0) {
 244                         lttng_ust_dl_dlmopen((void *) p->l_addr,
 245                                 nsid, p->l_name, flags,
 246                                 LTTNG_UST_CALLER_IP());
 247                 }
 248         }
 249         lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
 250         return handle;
 251
 252 }
 253 #endif
 254
 255 int dlclose(void *handle)
 256 {
 257         int ret;
 258
 259         if (__tracepoint_ptrs_registered) {
 260                 struct link_map *p = NULL;
 261
 262                 ret = dlinfo(handle, RTLD_DI_LINKMAP, &p);
 263                 if (ret != -1 && p != NULL && p->l_addr != 0) {
 264                         tracepoint(lttng_ust_dl, dlclose,
 265                                 LTTNG_UST_CALLER_IP(),
 266                                 (void *) p->l_addr);
 267                 }
 268         }
 269         ret = _lttng_ust_dl_libc_dlclose(handle);
 270         lttng_ust_dl_update(LTTNG_UST_CALLER_IP());
 271         return ret;
 272 }