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)
218
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