/* dlclose -- Close a handle opened by `dlopen'. Copyright (C) 1995 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <link.h> #include <dlfcn.h> #include <stdlib.h> #include <sys/types.h> #include <sys/mman.h> #define LOSE(s) _dl_signal_error (0, map->l_name, s) int dlclose (void *handle) { void doit (void) { struct link_map *map = handle; if (map->l_opencount == 0) LOSE ("shared object not open"); /* Decrement the reference count. */ --map->l_opencount; if (map->l_opencount == 0 && map->l_type == lt_loaded) { /* That was the last reference, and this was a dlopen-loaded object. We can unmap it. */ const Elf32_Phdr *ph; if (map->l_info[DT_FINI]) /* Call its termination function. */ (*(void (*) (void)) ((void *) map->l_addr + map->l_info[DT_FINI]->d_un.d_ptr)) (); if (map->l_info[DT_NEEDED]) { /* Also close all the dependencies. */ const char *strtab = (void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr; const Elf32_Dyn *d; for (d = map->l_ld; d->d_tag != DT_NULL; ++d) if (d->d_tag == DT_NEEDED) { /* It must already be open, since this one needed it; so dlopen will just find us its `struct link_map' and bump its reference count. */ struct link_map *o, *dep = dlopen (strtab + d->d_un.d_val, RTLD_LAZY); --dep->l_opencount; /* Lose the ref from that dlopen. */ /* Now we have the handle; we can close it for real. */ o = map; map = dep; doit (); map = o; } } /* Unmap the segments. */ for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph) if (ph->p_type == PT_LOAD) { Elf32_Addr mapstart = ph->p_vaddr & ~(ph->p_align - 1); Elf32_Addr mapend = ((ph->p_vaddr + ph->p_memsz + ph->p_align - 1) & ~(ph->p_align - 1)); munmap ((caddr_t) mapstart, mapend - mapstart); } /* Finally, unlink the data structure and free it. */ map->l_prev->l_next = map->l_next; if (map->l_next) map->l_next->l_prev = map->l_prev; free (map); } } return _dlerror_run (doit) ? -1 : 0; }