scripts/mod/modpost.h

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