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 struct buffer {
71 char *p;
72 int pos;
73 int size;
74 };
75
76 void __attribute__((format(printf, 2, 3)))
77 buf_printf(struct buffer *buf, const char *fmt, ...);
78
79 void
80 buf_write(struct buffer *buf, const char *s, int len);
81
82 struct module {
83 struct list_head list;
84 struct list_head exported_symbols;
85 struct list_head unresolved_symbols;
86 bool is_gpl_compatible;
87 bool from_dump; /* true if module was loaded from *.symvers */
88 bool is_vmlinux;
89 bool seen;
90 bool has_init;
91 bool has_cleanup;
92 bool is_protected; /* true if module exports are protected */
93 struct buffer dev_table_buf;
94 char srcversion[25];
95 // Missing namespace dependencies
96 struct list_head missing_namespaces;
97 // Actual imported namespaces
98 struct list_head imported_namespaces;
99 char name[];
100 };
101
102 struct elf_info {
103 size_t size;
104 Elf_Ehdr *hdr;
105 Elf_Shdr *sechdrs;
106 Elf_Sym *symtab_start;
107 Elf_Sym *symtab_stop;
108 unsigned int export_symbol_secndx; /* .export_symbol section */
109 char *strtab;
110 char *modinfo;
111 unsigned int modinfo_len;
112
113 /* support for 32bit section numbers */
114
115 unsigned int num_sections; /* max_secindex + 1 */
116 unsigned int secindex_strings;
117 /* if Nth symbol table entry has .st_shndx = SHN_XINDEX,
118 * take shndx from symtab_shndx_start[N] instead */
119 Elf32_Word *symtab_shndx_start;
120 Elf32_Word *symtab_shndx_stop;
121
122 struct symsearch *symsearch;
123 };
124
125 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
get_secindex(const struct elf_info * info,const Elf_Sym * sym)126 static inline unsigned int get_secindex(const struct elf_info *info,
127 const Elf_Sym *sym)
128 {
129 unsigned int index = sym->st_shndx;
130
131 /*
132 * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available
133 * in the .symtab_shndx section.
134 */
135 if (index == SHN_XINDEX)
136 return info->symtab_shndx_start[sym - info->symtab_start];
137
138 /*
139 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
140 * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real
141 * section indices.
142 */
143 if (index >= SHN_LORESERVE && index <= SHN_HIRESERVE)
144 return index - SHN_HIRESERVE - 1;
145
146 return index;
147 }
148
149 /*
150 * If there's no name there, ignore it; likewise, ignore it if it's
151 * one of the magic symbols emitted used by current tools.
152 *
153 * Internal symbols created by tools should be ignored by modpost.
154 */
is_valid_name(struct elf_info * elf,Elf_Sym * sym)155 static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym)
156 {
157 const char *name = elf->strtab + sym->st_name;
158
159 if (!name || !strlen(name))
160 return false;
161 return !is_mapping_symbol(name);
162 }
163
164 /* symsearch.c */
165 void symsearch_init(struct elf_info *elf);
166 void symsearch_finish(struct elf_info *elf);
167 Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr,
168 unsigned int secndx, bool allow_negative,
169 Elf_Addr min_distance);
170
171 /* file2alias.c */
172 void handle_moddevtable(struct module *mod, struct elf_info *info,
173 Elf_Sym *sym, const char *symname);
174 void add_moddevtable(struct buffer *buf, struct module *mod);
175
176 /* sumversion.c */
177 void get_src_version(const char *modname, char sum[], unsigned sumlen);
178
179 /* from modpost.c */
180 extern bool target_is_big_endian;
181 extern bool host_is_big_endian;
182 char *read_text_file(const char *filename);
183 char *get_line(char **stringp);
184 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);
185
186 void __attribute__((format(printf, 2, 3)))
187 modpost_log(bool is_error, const char *fmt, ...);
188
189 /*
190 * warn - show the given message, then let modpost continue running, still
191 * allowing modpost to exit successfully. This should be used when
192 * we still allow to generate vmlinux and modules.
193 *
194 * error - show the given message, then let modpost continue running, but fail
195 * in the end. This should be used when we should stop building vmlinux
196 * or modules, but we can continue running modpost to catch as many
197 * issues as possible.
198 *
199 * fatal - show the given message, and bail out immediately. This should be
200 * used when there is no point to continue running modpost.
201 */
202 #define warn(fmt, args...) modpost_log(false, fmt, ##args)
203 #define error(fmt, args...) modpost_log(true, fmt, ##args)
204 #define fatal(fmt, args...) do { error(fmt, ##args); exit(1); } while (1)
205