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 * @str: a string for MODULE_ALIAS()
103 */
104struct 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 * @no_trim_symbol: .no_trim_symbol section data
115 * @no_trim_symbol_len: length of the .no_trim_symbol section
116 */
117struct module {
118 struct list_head list;
119 struct list_head exported_symbols;
120 struct list_head unresolved_symbols;
121 const char *dump_file;
122 bool is_gpl_compatible;
123 bool is_vmlinux;
124 bool seen;
125 bool has_init;
126 bool has_cleanup;
127 char srcversion[25];
128 // Missing namespace dependencies
129 struct list_head missing_namespaces;
130 // Actual imported namespaces
131 struct list_head imported_namespaces;
132 struct list_head aliases;
133 char *no_trim_symbol;
134 unsigned int no_trim_symbol_len;
135 char name[];
136};
137
138struct elf_info {
139 size_t size;
140 Elf_Ehdr *hdr;
141 Elf_Shdr *sechdrs;
142 Elf_Sym *symtab_start;
143 Elf_Sym *symtab_stop;
144 unsigned int export_symbol_secndx; /* .export_symbol section */
145 char *strtab;
146 char *modinfo;
147 unsigned int modinfo_len;
148 char *no_trim_symbol;
149 unsigned int no_trim_symbol_len;
150
151 /* support for 32bit section numbers */
152
153 unsigned int num_sections; /* max_secindex + 1 */
154 unsigned int secindex_strings;
155 /* if Nth symbol table entry has .st_shndx = SHN_XINDEX,
156 * take shndx from symtab_shndx_start[N] instead */
157 Elf32_Word *symtab_shndx_start;
158 Elf32_Word *symtab_shndx_stop;
159
160 struct symsearch *symsearch;
161};
162
163/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
164static inline unsigned int get_secindex(const struct elf_info *info,
165 const Elf_Sym *sym)
166{
167 unsigned int index = sym->st_shndx;
168
169 /*
170 * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available
171 * in the .symtab_shndx section.
172 */
173 if (index == SHN_XINDEX)
174 return info->symtab_shndx_start[sym - info->symtab_start];
175
176 /*
177 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
178 * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real
179 * section indices.
180 */
181 if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE)
182 return index - SHN_HIRESERVE - 1;
183
184 return index;
185}
186
187/*
188 * If there's no name there, ignore it; likewise, ignore it if it's
189 * one of the magic symbols emitted used by current tools.
190 *
191 * Internal symbols created by tools should be ignored by modpost.
192 */
193static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym)
194{
195 const char *name = elf->strtab + sym->st_name;
196
197 if (!name || !strlen(s: name))
198 return false;
199 return !is_mapping_symbol(str: name);
200}
201
202/* symsearch.c */
203void symsearch_init(struct elf_info *elf);
204void symsearch_finish(struct elf_info *elf);
205Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr,
206 unsigned int secndx, bool allow_negative,
207 Elf_Addr min_distance);
208
209/* file2alias.c */
210void handle_moddevtable(struct module *mod, struct elf_info *info,
211 Elf_Sym *sym, const char *symname);
212
213/* sumversion.c */
214void get_src_version(const char *modname, char sum[], unsigned sumlen);
215
216/* from modpost.c */
217extern bool target_is_big_endian;
218extern bool host_is_big_endian;
219const char *get_basename(const char *path);
220char *read_text_file(const char *filename);
221char *get_line(char **stringp);
222void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);
223
224void __attribute__((format(printf, 2, 3)))
225modpost_log(bool is_error, const char *fmt, ...);
226
227/*
228 * warn - show the given message, then let modpost continue running, still
229 * allowing modpost to exit successfully. This should be used when
230 * we still allow to generate vmlinux and modules.
231 *
232 * error - show the given message, then let modpost continue running, but fail
233 * in the end. This should be used when we should stop building vmlinux
234 * or modules, but we can continue running modpost to catch as many
235 * issues as possible.
236 *
237 * fatal - show the given message, and bail out immediately. This should be
238 * used when there is no point to continue running modpost.
239 */
240#define warn(fmt, args...) modpost_log(false, fmt, ##args)
241#define error(fmt, args...) modpost_log(true, fmt, ##args)
242#define fatal(fmt, args...) do { error(fmt, ##args); exit(1); } while (1)
243

source code of linux/scripts/mod/modpost.h