| /* Set up the data structures for the system-supplied DSO. |
| Copyright (C) 2012-2018 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 Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| static inline void __attribute__ ((always_inline)) |
| setup_vdso (struct link_map *main_map __attribute__ ((unused)), |
| struct link_map ***first_preload __attribute__ ((unused))) |
| { |
| #ifdef NEED_DL_SYSINFO_DSO |
| if (GLRO(dl_sysinfo_dso) == NULL) |
| return; |
| |
| /* Do an abridged version of the work _dl_map_object_from_fd would do |
| to map in the object. It's already mapped and prelinked (and |
| better be, since it's read-only and so we couldn't relocate it). |
| We just want our data structures to describe it as if we had just |
| mapped and relocated it normally. */ |
| struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL, |
| 0, LM_ID_BASE); |
| if (__glibc_likely (l != NULL)) |
| { |
| static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro; |
| |
| l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso) |
| + GLRO(dl_sysinfo_dso)->e_phoff); |
| l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum; |
| for (uint_fast16_t i = 0; i < l->l_phnum; ++i) |
| { |
| const ElfW(Phdr) *const ph = &l->l_phdr[i]; |
| if (ph->p_type == PT_DYNAMIC) |
| { |
| l->l_ld = (void *) ph->p_vaddr; |
| l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn)); |
| } |
| else if (ph->p_type == PT_LOAD) |
| { |
| if (! l->l_addr) |
| l->l_addr = ph->p_vaddr; |
| if (ph->p_vaddr + ph->p_memsz >= l->l_map_end) |
| l->l_map_end = ph->p_vaddr + ph->p_memsz; |
| if ((ph->p_flags & PF_X) |
| && ph->p_vaddr + ph->p_memsz >= l->l_text_end) |
| l->l_text_end = ph->p_vaddr + ph->p_memsz; |
| } |
| else |
| /* There must be no TLS segment. */ |
| assert (ph->p_type != PT_TLS); |
| } |
| l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso); |
| l->l_addr = l->l_map_start - l->l_addr; |
| l->l_map_end += l->l_addr; |
| l->l_text_end += l->l_addr; |
| l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr); |
| elf_get_dynamic_info (l, dyn_temp); |
| _dl_setup_hash (l); |
| l->l_relocated = 1; |
| |
| /* The vDSO is always used. */ |
| l->l_used = 1; |
| |
| /* Initialize l_local_scope to contain just this map. This allows |
| the use of dl_lookup_symbol_x to resolve symbols within the vdso. |
| So we create a single entry list pointing to l_real as its only |
| element */ |
| l->l_local_scope[0]->r_nlist = 1; |
| l->l_local_scope[0]->r_list = &l->l_real; |
| |
| /* Now that we have the info handy, use the DSO image's soname |
| so this object can be looked up by name. Note that we do not |
| set l_name here. That field gives the file name of the DSO, |
| and this DSO is not associated with any file. */ |
| if (l->l_info[DT_SONAME] != NULL) |
| { |
| /* Work around a kernel problem. The kernel cannot handle |
| addresses in the vsyscall DSO pages in writev() calls. */ |
| const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB]) |
| + l->l_info[DT_SONAME]->d_un.d_val); |
| size_t len = strlen (dsoname) + 1; |
| char *copy = malloc (len); |
| if (copy == NULL) |
| _dl_fatal_printf ("out of memory\n"); |
| l->l_libname->name = l->l_name = memcpy (copy, dsoname, len); |
| } |
| |
| /* Add the vDSO to the object list. */ |
| _dl_add_to_namespace_list (l, LM_ID_BASE); |
| |
| # if IS_IN (rtld) |
| /* Rearrange the list so this DSO appears after rtld_map. */ |
| assert (l->l_next == NULL); |
| assert (l->l_prev == main_map); |
| GL(dl_rtld_map).l_next = l; |
| l->l_prev = &GL(dl_rtld_map); |
| *first_preload = &l->l_next; |
| # else |
| GL(dl_nns) = 1; |
| # endif |
| |
| /* We have a prelinked DSO preloaded by the system. */ |
| GLRO(dl_sysinfo_map) = l; |
| # ifdef NEED_DL_SYSINFO |
| if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT) |
| GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr; |
| # endif |
| } |
| #endif |
| } |