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 #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)