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