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.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 #if KERNEL_ELFDATA != HOST_ELFDATA 66 67 #define TO_NATIVE(x) (bswap(x)) 68 69 #else /* endianness matches */ 70 71 #define TO_NATIVE(x) (x) 72 73 #endif 74 75 #define NOFAIL(ptr) do_nofail((ptr), #ptr) 76 77 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) 78 79 void *do_nofail(void *ptr, const char *expr); 80 81 struct buffer { 82 char *p; 83 int pos; 84 int size; 85 }; 86 87 void __attribute__((format(printf, 2, 3))) 88 buf_printf(struct buffer *buf, const char *fmt, ...); 89 90 void 91 buf_write(struct buffer *buf, const char *s, int len); 92 93 struct module { 94 struct list_head list; 95 struct list_head exported_symbols; 96 struct list_head unresolved_symbols; 97 bool is_gpl_compatible; 98 bool from_dump; /* true if module was loaded from *.symvers */ 99 bool is_vmlinux; 100 bool seen; 101 bool has_init; 102 bool has_cleanup; 103 struct buffer dev_table_buf; 104 char srcversion[25]; 105 // Missing namespace dependencies 106 struct list_head missing_namespaces; 107 // Actual imported namespaces 108 struct list_head imported_namespaces; 109 char name[]; 110 }; 111 112 struct elf_info { 113 size_t size; 114 Elf_Ehdr *hdr; 115 Elf_Shdr *sechdrs; 116 Elf_Sym *symtab_start; 117 Elf_Sym *symtab_stop; 118 unsigned int export_symbol_secndx; /* .export_symbol section */ 119 char *strtab; 120 char *modinfo; 121 unsigned int modinfo_len; 122 123 /* support for 32bit section numbers */ 124 125 unsigned int num_sections; /* max_secindex + 1 */ 126 unsigned int secindex_strings; 127 /* if Nth symbol table entry has .st_shndx = SHN_XINDEX, 128 * take shndx from symtab_shndx_start[N] instead */ 129 Elf32_Word *symtab_shndx_start; 130 Elf32_Word *symtab_shndx_stop; 131 132 struct symsearch *symsearch; 133 }; 134 135 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ 136 static inline unsigned int get_secindex(const struct elf_info *info, 137 const Elf_Sym *sym) 138 { 139 unsigned int index = sym->st_shndx; 140 141 /* 142 * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available 143 * in the .symtab_shndx section. 144 */ 145 if (index == SHN_XINDEX) 146 return info->symtab_shndx_start[sym - info->symtab_start]; 147 148 /* 149 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of 150 * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real 151 * section indices. 152 */ 153 if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE) 154 return index - SHN_HIRESERVE - 1; 155 156 return index; 157 } 158 159 /* 160 * If there's no name there, ignore it; likewise, ignore it if it's 161 * one of the magic symbols emitted used by current tools. 162 * 163 * Internal symbols created by tools should be ignored by modpost. 164 */ 165 static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym) 166 { 167 const char *name = elf->strtab + sym->st_name; 168 169 if (!name || !strlen(name)) 170 return false; 171 return !is_mapping_symbol(name); 172 } 173 174 /* symsearch.c */ 175 void symsearch_init(struct elf_info *elf); 176 void symsearch_finish(struct elf_info *elf); 177 Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, 178 unsigned int secndx, bool allow_negative, 179 Elf_Addr min_distance); 180 181 /* file2alias.c */ 182 void handle_moddevtable(struct module *mod, struct elf_info *info, 183 Elf_Sym *sym, const char *symname); 184 void add_moddevtable(struct buffer *buf, struct module *mod); 185 186 /* sumversion.c */ 187 void get_src_version(const char *modname, char sum[], unsigned sumlen); 188 189 /* from modpost.c */ 190 char *read_text_file(const char *filename); 191 char *get_line(char **stringp); 192 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym); 193 194 enum loglevel { 195 LOG_WARN, 196 LOG_ERROR, 197 }; 198 199 void __attribute__((format(printf, 2, 3))) 200 modpost_log(enum loglevel loglevel, const char *fmt, ...); 201 202 /* 203 * warn - show the given message, then let modpost continue running, still 204 * allowing modpost to exit successfully. This should be used when 205 * we still allow to generate vmlinux and modules. 206 * 207 * error - show the given message, then let modpost continue running, but fail 208 * in the end. This should be used when we should stop building vmlinux 209 * or modules, but we can continue running modpost to catch as many 210 * issues as possible. 211 * 212 * fatal - show the given message, and bail out immediately. This should be 213 * used when there is no point to continue running modpost. 214 */ 215 #define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args) 216 #define error(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args) 217 #define fatal(fmt, args...) do { error(fmt, ##args); exit(1); } while (1) 218