liblttng-ust-dl/ustdl.c

   1 /*
   2  * Copyright (C) 2013  Paul Woegerer <paul.woegerer@mentor.com>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; version 2.1 of
   7  * the License.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <inttypes.h>
  21 #include <dlfcn.h>
  22 #include <link.h>
  23 #include <unistd.h>
  24 #include <stdio.h>
  25 #include <signal.h>
  26 #include <sched.h>
  27 #include <stdarg.h>
  28 #include "usterr.h"
  29
  30 #include <lttng/ust-compiler.h>
  31 #include <lttng/ust.h>
  32
  33 static void *(*__lttng_ust_plibc_dlopen)(const char *filename, int flag);
  34 static int (*__lttng_ust_plibc_dlclose)(void *handle);
  35 static void *__lttng_ust_baddr_handle;
  36
  37 static
  38 void *_lttng_ust_dl_libc_dlopen(const char *filename, int flag)
  39 {
  40         if (!__lttng_ust_plibc_dlopen) {
  41                 __lttng_ust_plibc_dlopen = dlsym(RTLD_NEXT, "dlopen");
  42                 if (__lttng_ust_plibc_dlopen == NULL) {
  43                         fprintf(stderr, "%s\n", dlerror());
  44                         return NULL;
  45                 }
  46         }
  47         return __lttng_ust_plibc_dlopen(filename, flag);
  48 }
  49
  50 static
  51 int _lttng_ust_dl_libc_dlclose(void *handle)
  52 {
  53         if (!__lttng_ust_plibc_dlclose) {
  54                 __lttng_ust_plibc_dlclose = dlsym(RTLD_NEXT, "dlclose");
  55                 if (__lttng_ust_plibc_dlclose == NULL) {
  56                         fprintf(stderr, "%s\n", dlerror());
  57                         return -1;
  58                 }
  59         }
  60         return __lttng_ust_plibc_dlclose(handle);
  61 }
  62
  63 static
  64 void *lttng_ust_baddr_handle(void)
  65 {
  66         if (!__lttng_ust_baddr_handle) {
  67                 __lttng_ust_baddr_handle = _lttng_ust_dl_libc_dlopen(
  68                         "liblttng-ust-baddr.so.0", RTLD_NOW | RTLD_GLOBAL);
  69                 if (__lttng_ust_baddr_handle == NULL)
  70                         fprintf(stderr, "%s\n", dlerror());
  71         }
  72         return __lttng_ust_baddr_handle;
  73 }
  74
  75 static
  76 int lttng_ust_baddr_push(void *so_base, const char *so_name)
  77 {
  78         static int
  79         (*lttng_ust_baddr_push_fn)(void *so_base, const char *so_name);
  80         if (!lttng_ust_baddr_push_fn) {
  81                 void *baddr_handle = lttng_ust_baddr_handle();
  82                 if (baddr_handle) {
  83                         lttng_ust_baddr_push_fn = dlsym(baddr_handle,
  84                                 "lttng_ust_push_baddr");
  85                         if (lttng_ust_baddr_push_fn == NULL)
  86                                 fprintf(stderr, "%s\n", dlerror());
  87                 }
  88                 if (!lttng_ust_baddr_push_fn)
  89                         return -1;
  90         }
  91         return lttng_ust_baddr_push_fn(so_base, so_name);
  92 }
  93
  94 static
  95 int lttng_ust_baddr_pop(void *so_base)
  96 {
  97         static int
  98         (*lttng_ust_baddr_pop_fn)(void *so_base);
  99         if (!lttng_ust_baddr_pop_fn) {
 100                 void *baddr_handle = lttng_ust_baddr_handle();
 101                 if (baddr_handle) {
 102                         lttng_ust_baddr_pop_fn = dlsym(baddr_handle,
 103                                 "lttng_ust_pop_baddr");
 104                         if (lttng_ust_baddr_pop_fn == NULL)
 105                                 fprintf(stderr, "%s\n", dlerror());
 106                 }
 107                 if (!lttng_ust_baddr_pop_fn)
 108                         return -1;
 109         }
 110         return lttng_ust_baddr_pop_fn(so_base);
 111 }
 112
 113 void *dlopen(const char *filename, int flag)
 114 {
 115         void *handle = _lttng_ust_dl_libc_dlopen(filename, flag);
 116         if (handle) {
 117                 struct link_map *p = NULL;
 118                 if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL
 119                                 && p->l_addr != 0)
 120                         lttng_ust_baddr_push((void *) p->l_addr, p->l_name);
 121         }
 122         return handle;
 123 }
 124
 125 int dlclose(void *handle)
 126 {
 127         if (handle) {
 128                 struct link_map *p = NULL;
 129                 if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL
 130                                 && p->l_addr != 0)
 131                         lttng_ust_baddr_pop((void *) p->l_addr);
 132         }
 133         return _lttng_ust_dl_libc_dlclose(handle);
 134 }
 135
 136 static void __attribute__((destructor))
 137 lttng_ust_baddr_handle_fini(void);
 138 static void
 139 lttng_ust_baddr_handle_fini(void)
 140 {
 141         if (__lttng_ust_baddr_handle) {
 142                 int ret = _lttng_ust_dl_libc_dlclose(__lttng_ust_baddr_handle);
 143                 if (ret)
 144                         fprintf(stderr, "%s\n", dlerror());
 145         }
 146 }