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
 86struct buffer {
 87	char *p;
 88	int pos;
 89	int size;
 90};
 91
 92void __attribute__((format(printf, 2, 3)))
 93buf_printf(struct buffer *buf, const char *fmt, ...);
 94
 95void
 96buf_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 */
105struct 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 */
119struct 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
140struct 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" */
166static 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 */
195static 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 */
205void symsearch_init(struct elf_info *elf);
206void symsearch_finish(struct elf_info *elf);
207Elf_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 */
212void handle_moddevtable(struct module *mod, struct elf_info *info,
213			Elf_Sym *sym, const char *symname);
214
215/* sumversion.c */
216void get_src_version(const char *modname, char sum[], unsigned sumlen);
217
218/* from modpost.c */
219extern bool target_is_big_endian;
220extern bool host_is_big_endian;
221const char *get_basename(const char *path);
222char *read_text_file(const char *filename);
223char *get_line(char **stringp);
224void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);
225
226void __attribute__((format(printf, 2, 3)))
227modpost_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)