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 <limits.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <signal.h>
  29 #include <sched.h>
  30 #include <stdarg.h>
  31 #include "usterr.h"
  32
  33 #include <lttng/ust-compiler.h>
  34 #include <lttng/ust.h>
  35
  36 #define TRACEPOINT_DEFINE
  37 #include "ust_baddr.h"
  38
  39 static void *(*__lttng_ust_plibc_dlopen)(const char *filename, int flag);
  40 static int (*__lttng_ust_plibc_dlclose)(void *handle);
  41
  42 static
  43 void *_lttng_ust_dl_libc_dlopen(const char *filename, int flag)
  44 {
  45         if (!__lttng_ust_plibc_dlopen) {
  46                 __lttng_ust_plibc_dlopen = dlsym(RTLD_NEXT, "dlopen");
  47                 if (__lttng_ust_plibc_dlopen == NULL) {
  48                         fprintf(stderr, "%s\n", dlerror());
  49                         return NULL;
  50                 }
  51         }
  52         return __lttng_ust_plibc_dlopen(filename, flag);
  53 }
  54
  55 static
  56 int _lttng_ust_dl_libc_dlclose(void *handle)
  57 {
  58         if (!__lttng_ust_plibc_dlclose) {
  59                 __lttng_ust_plibc_dlclose = dlsym(RTLD_NEXT, "dlclose");
  60                 if (__lttng_ust_plibc_dlclose == NULL) {
  61                         fprintf(stderr, "%s\n", dlerror());
  62                         return -1;
  63                 }
  64         }
  65         return __lttng_ust_plibc_dlclose(handle);
  66 }
  67
  68 static
  69 void lttng_ust_baddr_push(void *so_base, const char *so_name)
  70 {
  71         char resolved_path[PATH_MAX];
  72         struct stat sostat;
  73
  74         if (!realpath(so_name, resolved_path)) {
  75                 ERR("could not resolve path '%s'", so_name);
  76                 return;
  77         }
  78
  79         if (stat(resolved_path, &sostat)) {
  80                 ERR("could not access file status for %s", resolved_path);
  81                 return;
  82         }
  83
  84         tracepoint(ust_baddr, push,
  85                 so_base, resolved_path, sostat.st_size, sostat.st_mtime);
  86         return;
  87 }
  88
  89 void *dlopen(const char *filename, int flag)
  90 {
  91         void *handle = _lttng_ust_dl_libc_dlopen(filename, flag);
  92         if (handle) {
  93                 struct link_map *p = NULL;
  94                 if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL
  95                                 && p->l_addr != 0)
  96                         lttng_ust_baddr_push((void *) p->l_addr, p->l_name);
  97         }
  98         return handle;
  99 }
 100
 101 int dlclose(void *handle)
 102 {
 103         if (handle) {
 104                 struct link_map *p = NULL;
 105                 if (dlinfo(handle, RTLD_DI_LINKMAP, &p) != -1 && p != NULL
 106                                 && p->l_addr != 0)
 107                         tracepoint(ust_baddr, pop, (void *) p->l_addr);
 108         }
 109         return _lttng_ust_dl_libc_dlclose(handle);
 110 }