1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include <byteswap.h> 3 #include <stdbool.h> 4 #include <stdio.h> 5 #include <stdlib.h> 6 #include <stdarg.h> 7 #include <string.h> 8 #include <sys/types.h> 9 #include <sys/stat.h> 10 #include <sys/mman.h> 11 #include <fcntl.h> 12 #include <unistd.h> 13 #include <elf.h> 14 #include "../../include/linux/module_symbol.h" 15 16 #include <list_types.h> 17 #include "elfconfig.h" 18 19 /* On BSD-alike OSes elf.h defines these according to host's word size */ 20 #undef ELF_ST_BIND 21 #undef ELF_ST_TYPE 22 #undef ELF_R_SYM 23 #undef ELF_R_TYPE 24 25 #if KERNEL_ELFCLASS == ELFCLASS32 26 27 #define Elf_Ehdr Elf32_Ehdr 28 #define Elf_Shdr Elf32_Shdr 29 #define Elf_Sym Elf32_Sym 30 #define Elf_Addr Elf32_Addr 31 #define Elf_Section Elf32_Half 32 #define ELF_ST_BIND ELF32_ST_BIND 33 #define ELF_ST_TYPE ELF32_ST_TYPE 34 35 #define Elf_Rel Elf32_Rel 36 #define Elf_Rela Elf32_Rela 37 #define ELF_R_SYM ELF32_R_SYM 38 #define ELF_R_TYPE ELF32_R_TYPE 39 #else 40 41 #define Elf_Ehdr Elf64_Ehdr 42 #define Elf_Shdr Elf64_Shdr 43 #define Elf_Sym Elf64_Sym 44 #define Elf_Addr Elf64_Addr 45 #define Elf_Section Elf64_Half 46 #define ELF_ST_BIND ELF64_ST_BIND 47 #define ELF_ST_TYPE ELF64_ST_TYPE 48 49 #define Elf_Rel Elf64_Rel 50 #define Elf_Rela Elf64_Rela 51 #define ELF_R_SYM ELF64_R_SYM 52 #define ELF_R_TYPE ELF64_R_TYPE 53 #endif 54 55 #define bswap(x) \ 56 ({ \ 57 _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ 58 sizeof(x) == 4 || sizeof(x) == 8, "bug"); \ 59 (typeof(x))(sizeof(x) == 2 ? bswap_16(x) : \ 60 sizeof(x) == 4 ? bswap_32(x) : \ 61 sizeof(x) == 8 ? bswap_64(x) : \ 62 x); \ 63 }) 64 65 #define TO_NATIVE(x) \ 66 (target_is_big_endian == host_is_big_endian ? x : bswap(x)) 67 68 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) 69 70 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) 71 72 struct buffer { 73 char *p; 74 int pos; 75 int size; 76 }; 77 78 void __attribute__((format(printf, 2, 3))) 79 buf_printf(struct buffer *buf, const char *fmt, ...); 80 81 void 82 buf_write(struct buffer *buf, const char *s, int len); 83 84 /** 85 * struct module_alias - auto-generated MODULE_ALIAS() 86 * 87 * @node: linked to module::aliases 88 * @str: a string for MODULE_ALIAS() 89 */ 90 struct module_alias { 91 struct list_head node; 92 char str[]; 93 }; 94 95 /** 96 * struct module - represent a module (vmlinux or *.ko) 97 * 98 * @dump_file: path to the .symvers file if loaded from a file 99 * @aliases: list head for module_aliases 100 */ 101 struct module { 102 struct list_head list; 103 struct list_head exported_symbols; 104 struct list_head unresolved_symbols; 105 const char *dump_file; 106 bool is_gpl_compatible; 107 bool is_vmlinux; 108 bool seen; 109 bool has_init; 110 bool has_cleanup; 111 char srcversion[25]; 112 // Missing namespace dependencies 113 struct list_head missing_namespaces; 114 // Actual imported namespaces 115 struct list_head imported_namespaces; 116 struct list_head aliases; 117 char name[]; 118 }; 119 120 struct elf_info { 121 size_t size; 122 Elf_Ehdr *hdr; 123 Elf_Shdr *sechdrs; 124 Elf_Sym *symtab_start; 125 Elf_Sym *symtab_stop; 126 unsigned int export_symbol_secndx; /* .export_symbol section */ 127 char *strtab; 128 char *modinfo; 129 unsigned int modinfo_len; 130 131 /* support for 32bit section numbers */ 132 133 unsigned int num_sections; /* max_secindex + 1 */ 134 unsigned int secindex_strings; 135 /* if Nth symbol table entry has .st_shndx = SHN_XINDEX, 136 * take shndx from symtab_shndx_start[N] instead */ 137 Elf32_Word *symtab_shndx_start; 138 Elf32_Word *symtab_shndx_stop; 139 140 struct symsearch *symsearch; 141 }; 142 143 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ 144 static inline unsigned int get_secindex(const struct elf_info *info, 145 const Elf_Sym *sym) 146 { 147 unsigned int index = sym->st_shndx; 148 149 /* 150 * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available 151 * in the .symtab_shndx section. 152 */ 153 if (index == SHN_XINDEX) 154 return info->symtab_shndx_start[sym - info->symtab_start]; 155 156 /* 157 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of 158 * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real 159 * section indices. 160 */ 161 if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE) 162 return index - SHN_HIRESERVE - 1; 163 164 return index; 165 } 166 167 /* 168 * If there's no name there, ignore it; likewise, ignore it if it's 169 * one of the magic symbols emitted used by current tools. 170 * 171 * Internal symbols created by tools should be ignored by modpost. 172 */ 173 static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym) 174 { 175 const char *name = elf->strtab + sym->st_name; 176 177 if (!name || !strlen(name)) 178 return false; 179 return !is_mapping_symbol(name); 180 } 181 182 /* symsearch.c */ 183 void symsearch_init(struct elf_info *elf); 184 void symsearch_finish(struct elf_info *elf); 185 Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, 186 unsigned int secndx, bool allow_negative, 187 Elf_Addr min_distance); 188 189 /* file2alias.c */ 190 void handle_moddevtable(struct module *mod, struct elf_info *info, 191 Elf_Sym *sym, const char *symname); 192 193 /* sumversion.c */ 194 void get_src_version(const char *modname, char sum[], unsigned sumlen); 195 196 /* from modpost.c */ 197 extern bool target_is_big_endian; 198 extern bool host_is_big_endian; 199 char *read_text_file(const char *filename); 200 char *get_line(char **stringp); 201 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym); 202 203 void __attribute__((format(printf, 2, 3))) 204 modpost_log(bool is_error, const char *fmt, ...); 205 206 /* 207 * warn - show the given message, then let modpost continue running, still 208 * allowing modpost to exit successfully. This should be used when 209 * we still allow to generate vmlinux and modules. 210 * 211 * error - show the given message, then let modpost continue running, but fail 212 * in the end. This should be used when we should stop building vmlinux 213 * or modules, but we can continue running modpost to catch as many 214 * issues as possible. 215 * 216 * fatal - show the given message, and bail out immediately. This should be 217 * used when there is no point to continue running modpost. 218 */ 219 #define warn(fmt, args...) modpost_log(false, fmt, ##args) 220 #define error(fmt, args...) modpost_log(true, fmt, ##args) 221 #define fatal(fmt, args...) do { error(fmt, ##args); exit(1); } while (1) 222