diff options
Diffstat (limited to 'elf/dlclose.c')
| -rw-r--r-- | elf/dlclose.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/elf/dlclose.c b/elf/dlclose.c new file mode 100644 index 0000000000..4aa4085f66 --- /dev/null +++ b/elf/dlclose.c @@ -0,0 +1,97 @@ +/* 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, 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; +} + |