1 /* Accumulation of various pieces of knowledge about ELF. 2 Copyright (C) 2000-2012, 2014 Red Hat, Inc. 3 This file is part of elfutils. 4 Written by Ulrich Drepper <drepper (at) redhat.com>, 2000. 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 #ifndef _ELF_KNOWLEDGE_H 31 #define _ELF_KNOWLEDGE_H 1 32 33 #include <stdbool.h> 34 35 36 /* Test whether a section can be stripped or not. */ 37 #define SECTION_STRIP_P(shdr, name, remove_comment) \ 38 /* Sections which are allocated are not removed. */ \ 39 (((shdr)->sh_flags & SHF_ALLOC) == 0 \ 40 /* We never remove .note sections. */ \ 41 && (shdr)->sh_type != SHT_NOTE \ 42 && (((shdr)->sh_type) != SHT_PROGBITS \ 43 /* Never remove .gnu.warning.* sections. */ \ 44 || (name != NULL \ 45 && strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) != 0\ 46 /* We remove .comment sections only if explicitly told to do so. */\ 47 && (remove_comment \ 48 || strcmp (name, ".comment") != 0)))) 49 50 51 /* Test whether `sh_info' field in section header contains a section 52 index. There are two kinds of sections doing this: 53 54 - the sections containing relocation information reference in this 55 field the section to which the relocations apply; 56 57 - section with the SHF_INFO_LINK flag set to signal that `sh_info' 58 references a section. This allows correct handling of unknown 59 sections. */ 60 #define SH_INFO_LINK_P(Shdr) \ 61 ((Shdr)->sh_type == SHT_REL || (Shdr)->sh_type == SHT_RELA \ 62 || ((Shdr)->sh_flags & SHF_INFO_LINK) != 0) 63 64 65 /* When combining ELF section flags we must distinguish two kinds: 66 67 - flags which cause problem if not added to the result even if not 68 present in all input sections 69 70 - flags which cause problem if added to the result if not present 71 in all input sections 72 73 The following definition is for the general case. There might be 74 machine specific extensions. */ 75 #define SH_FLAGS_COMBINE(Flags1, Flags2) \ 76 (((Flags1 | Flags2) \ 77 & (SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR | SHF_LINK_ORDER \ 78 | SHF_OS_NONCONFORMING | SHF_GROUP)) \ 79 | (Flags1 & Flags2 & (SHF_MERGE | SHF_STRINGS | SHF_INFO_LINK))) 80 81 /* Similar macro: return the bits of the flags which necessarily must 82 match if two sections are automatically combined. Sections still 83 can be forcefully combined in which case SH_FLAGS_COMBINE can be 84 used to determine the combined flags. */ 85 #define SH_FLAGS_IMPORTANT(Flags) \ 86 ((Flags) & ~((GElf_Xword) 0 | SHF_LINK_ORDER | SHF_OS_NONCONFORMING)) 87 88 89 /* Size of an entry in the hash table. The ELF specification says all 90 entries are regardless of platform 32-bits in size. Early 64-bit 91 ports (namely Alpha for Linux) got this wrong. The wording was not 92 clear. 93 94 Several years later the ABI for the 64-bit S390s was developed. 95 Many things were copied from the IA-64 ABI (which uses the correct 96 32-bit entry size) but what do these people do? They use 64-bit 97 entries. It is really shocking to see what kind of morons are out 98 there. And even worse: they are allowed to design ABIs. */ 99 #define SH_ENTSIZE_HASH(Ehdr) \ 100 ((Ehdr)->e_machine == EM_ALPHA \ 101 || ((Ehdr)->e_machine == EM_S390 \ 102 && (Ehdr)->e_ident[EI_CLASS] == ELFCLASS64) ? 8 : 4) 103 104 #endif /* elf-knowledge.h */ 105
