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 __get_unaligned_t(type, ptr) ({ \ 69 const struct { type x; } __attribute__((__packed__)) *__pptr = \ 70 (typeof(__pptr))(ptr); \ 71 __pptr->x; \ 72 }) 73 74 #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) 75 76 #define get_unaligned_native(ptr) \ 77 ({ \ 78 typeof(*(ptr)) _val = get_unaligned(ptr); \ 79 TO_NATIVE(_val); \ 80 }) 81 82 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) 83 84 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) 85 86 struct buffer { 87 char *p; 88 int pos; 89 int size; 90 }; 91 92 void __attribute__((format(printf, 2, 3))) 93 buf_printf(struct buffer *buf, const char *fmt, ...); 94 95 void 96 buf_write(struct buffer *buf, const char *s, int len); 97 98 /** 99 * struct module_alias - auto-generated MODULE_ALIAS() 100 * 101 * @node: linked to module::aliases 102 * @modname: name of the builtin module (only for vmlinux) 103 * @str: a string for MODULE_ALIAS() 104 */ 105 struct module_alias { 106 struct list_head node; 107 char *builtin_modname; 108 char str[]; 109 }; 110 111 /** 112 * struct module - represent a module (vmlinux or *.ko) 113 * 114 * @dump_file: path to the .symvers file if loaded from a file 115 * @aliases: list head for module_aliases 116 * @no_trim_symbol: .no_trim_symbol section data 117 * @no_trim_symbol_len: length of the .no_trim_symbol section 118 */ 119 struct module { 120 struct list_head list; 121 struct list_head exported_symbols; 122 struct list_head unresolved_symbols; 123 const char *dump_file; 124 bool is_gpl_compatible; 125 bool is_vmlinux; 126 bool seen; 127 bool has_init; 128 bool has_cleanup; 129 char srcversion[25]; 130 // Missing namespace dependencies 131 struct list_head missing_namespaces; 132 // Actual imported namespaces 133 struct list_head imported_namespaces; 134 struct list_head aliases; 135 char *no_trim_symbol; 136 unsigned int no_trim_symbol_len; 137 char name[]; 138 }; 139 140 struct elf_info { 141 size_t size; 142 Elf_Ehdr *hdr; 143 Elf_Shdr *sechdrs; 144 Elf_Sym *symtab_start; 145 Elf_Sym *symtab_stop; 146 unsigned int export_symbol_secndx; /* .export_symbol section */ 147 char *strtab; 148 char *modinfo; 149 unsigned int modinfo_len; 150 char *no_trim_symbol; 151 unsigned int no_trim_symbol_len; 152 153 /* support for 32bit section numbers */ 154 155 unsigned int num_sections; /* max_secindex + 1 */ 156 unsigned int secindex_strings; 157 /* if Nth symbol table entry has .st_shndx = SHN_XINDEX, 158 * take shndx from symtab_shndx_start[N] instead */ 159 Elf32_Word *symtab_shndx_start; 160 Elf32_Word *symtab_shndx_stop; 161 162 struct symsearch *symsearch; 163 }; 164 165 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ 166 static inline unsigned int get_secindex(const struct elf_info *info, 167 const Elf_Sym *sym) 168 { 169 unsigned int index = sym->st_shndx; 170 171 /* 172 * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available 173 * in the .symtab_shndx section. 174 */ 175 if (index == SHN_XINDEX) 176 return info->symtab_shndx_start[sym - info->symtab_start]; 177 178 /* 179 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of 180 * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real 181 * section indices. 182 */ 183 if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE) 184 return index - SHN_HIRESERVE - 1; 185 186 return index; 187 } 188 189 /* 190 * If there's no name there, ignore it; likewise, ignore it if it's 191 * one of the magic symbols emitted used by current tools. 192 * 193 * Internal symbols created by tools should be ignored by modpost. 194 */ 195 static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym) 196 { 197 const char *name = elf->strtab + sym->st_name; 198 199 if (!name || !strlen(name)) 200 return false; 201 return !is_mapping_symbol(name); 202 } 203 204 /* symsearch.c */ 205 void symsearch_init(struct elf_info *elf); 206 void symsearch_finish(struct elf_info *elf); 207 Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, 208 unsigned int secndx, bool allow_negative, 209 Elf_Addr min_distance); 210 211 /* file2alias.c */ 212 void handle_moddevtable(struct module *mod, struct elf_info *info, 213 Elf_Sym *sym, const char *symname); 214 215 /* sumversion.c */ 216 void get_src_version(const char *modname, char sum[], unsigned sumlen); 217 218 /* from modpost.c */ 219 extern bool target_is_big_endian; 220 extern bool host_is_big_endian; 221 const char *get_basename(const char *path); 222 char *read_text_file(const char *filename); 223 char *get_line(char **stringp); 224 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym); 225 226 void __attribute__((format(printf, 2, 3))) 227 modpost_log(bool is_error, const char *fmt, ...); 228 229 /* 230 * warn - show the given message, then let modpost continue running, still 231 * allowing modpost to exit successfully. This should be used when 232 * we still allow to generate vmlinux and modules. 233 * 234 * error - show the given message, then let modpost continue running, but fail 235 * in the end. This should be used when we should stop building vmlinux 236 * or modules, but we can continue running modpost to catch as many 237 * issues as possible. 238 * 239 * fatal - show the given message, and bail out immediately. This should be 240 * used when there is no point to continue running modpost. 241 */ 242 #define warn(fmt, args...) modpost_log(false, fmt, ##args) 243 #define error(fmt, args...) modpost_log(true, fmt, ##args) 244 #define fatal(fmt, args...) do { error(fmt, ##args); exit(1); } while (1) 245