Intel平台下Linux中 ELF文档动态链接的加载、解析及实例分析（一）: 加载

_dl_open() >> dl_open_worker() >> _dl_map_object()
  1693 struct link_map *
  1694 internal_function
  1695 _dl_map_object (struct link_map *loader, const char *name, int preloaded,
  1696   int type, int trace_mode, int mode)
  1697 {
  1698   int fd;
  1699   char *realname;
  1700   char *name_copy;
  1701   struct link_map *l;
  1702   struct filebuf fb;
  1703 
  1704 
  1705   /* Look for this name among those already loaded.  */
  1706   for (l = GL(dl_loaded); l; l = l->l_next)
  1707    {
  1708        if (!_dl_name_match_p (name, l))
…………….
  1721        return l;
  1722    } 
  1723 
  1724    fd = open_path (name, namelen, preloaded, &env_path_list,
  1725    &realname, &fb);
  1726 
  1727    l = _dl_new_object (name_copy, name, type, loader);
  1728 
  1729    return _dl_map_object_from_fd (name, fd, &fb, realname, loader, type, mode);
  1730 
  1731 
1732 }/*end of _dl_map_object*/

    _dl_open() >> dl_open_worker() >> _dl_map_object() >> open_path()
  1289 static int open_path (const char *name, size_t namelen, int preloaded,
  1290     struct r_search_path_struct *sps, char **realname,
  1291     struct filebuf *fbp)
  1292 
  1293 {
  1294   struct r_search_path_elem **dirs = sps->dirs;
  1295   char *buf;
  1296   int fd = -1;
  1297   const char *current_what = NULL;
  1298   int any = 0;
  1299 
  1300   buf = alloca (max_dirnamelen   max_capstrlen   namelen);
  1301 
  1302   do
  1303     {
  1304       struct r_search_path_elem *this_dir = *dirs;
  1305       size_t buflen = 0;
 ………………
  1310      struct stat64 st;
  1311      
  1312 
  1313       edp = (char *) __mempcpy (buf, this_dir->dirname, this_dir->dirnamelen);
  1314       for (cnt = 0; fd == -1 && cnt < ncapstr;   cnt)
  1315  {
  1316    /* Skip this directory if we know it does not exist.  */
  1317    if (this_dir->status[cnt] == nonexisting)
  1318      continue;
  1319 
  1320    buflen = ((char *) __mempcpy (__mempcpy (edp, capstr[cnt].str,
  1321          capstr[cnt].len), name, namelen)- buf);
  1322 
  1323   
  1324    fd = open_verify (buf, fbp);
  1325         
  1326         
  1327    __xstat64 (_STAT_VER, buf, &st);
  1328    
  1329   
  1341  }
  1342 
…………….
    1358  }
    

strncpy(edp, capstr[cnt].str, capstr[cnt].len);
edp =capstr[cnt].len;
strncpy(edp,name, namelen);
edp =namelen;
buflen=edp-buf;