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1 : : /* Coordinate ELF library and application versions. 2 : : Copyright (C) 1998, 1999, 2000, 2002, 2015 Red Hat, Inc. 3 : : This file is part of elfutils. 4 : : Contributed by Ulrich Drepper <drepper@redhat.com>, 1998. 5 : : 6 : : This file is free software; you can redistribute it and/or modify 7 : : it under the terms of either 8 : : 9 : : * the GNU Lesser General Public License as published by the Free 10 : : Software Foundation; either version 3 of the License, or (at 11 : : your option) any later version 12 : : 13 : : or 14 : : 15 : : * the GNU General Public License as published by the Free 16 : : Software Foundation; either version 2 of the License, or (at 17 : : your option) any later version 18 : : 19 : : or both in parallel, as here. 20 : : 21 : : elfutils is distributed in the hope that it will be useful, but 22 : : WITHOUT ANY WARRANTY; without even the implied warranty of 23 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 24 : : General Public License for more details. 25 : : 26 : : You should have received copies of the GNU General Public License and 27 : : the GNU Lesser General Public License along with this program. If 28 : : not, see <http://www.gnu.org/licenses/>. */ 29 : : 30 : : #ifdef HAVE_CONFIG_H 31 : : # include <config.h> 32 : : #endif 33 : : 34 : : #include <libelfP.h> 35 : : #include <pthread.h> 36 : : 37 : : /* Multiple threads may initialize __libelf_version. 38 : : pthread_once() ensures that __libelf_version is initialized only once. */ 39 : : once_define(static, version_once); 40 : : 41 : : /* Currently selected version. Should be EV_CURRENT. 42 : : Will be EV_NONE if elf_version () has not been called yet. */ 43 : : unsigned int __libelf_version = EV_NONE; 44 : : 45 : 8190 : static void initialize_version(void) 46 : : { 47 : 8190 : __libelf_version = EV_CURRENT; 48 : : } 49 : : 50 : : unsigned int 51 : 8190 : elf_version (unsigned int version) 52 : : { 53 [ - + ]: 8190 : if (version == EV_NONE) 54 : : return EV_CURRENT; 55 : : 56 [ + - ]: 8190 : if (likely (version == EV_CURRENT)) 57 : : { 58 : : /* Phew, we know this version. */ 59 : : 60 : : /* Signal that the version is now initialized. */ 61 : 8190 : once(version_once, initialize_version); 62 : : 63 : : /* And return the last (or initial) version. */ 64 : 8190 : return EV_CURRENT; 65 : : } 66 : : 67 : : /* We cannot handle this version. */ 68 : 0 : __libelf_seterrno (ELF_E_UNKNOWN_VERSION); 69 : 0 : return EV_NONE; 70 : : } 71 : : INTDEF(elf_version)