xref: /linux/scripts/mod/modpost.h (revision 69b54314c975f4dfd3a29d6b9211ab68fff46682)
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  
86  struct buffer {
87  	char *p;
88  	int pos;
89  	int size;
90  };
91  
92  void __attribute__((format(printf, 2, 3)))
93  buf_printf(struct buffer *buf, const char *fmt, ...);
94  
95  void
96  buf_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   */
104  struct 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   */
117  struct 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  
138  struct 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" */
get_secindex(const struct elf_info * info,const Elf_Sym * sym)164  static 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   */
is_valid_name(struct elf_info * elf,Elf_Sym * sym)193  static 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(name))
198  		return false;
199  	return !is_mapping_symbol(name);
200  }
201  
202  /* symsearch.c */
203  void symsearch_init(struct elf_info *elf);
204  void symsearch_finish(struct elf_info *elf);
205  Elf_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 */
210  void handle_moddevtable(struct module *mod, struct elf_info *info,
211  			Elf_Sym *sym, const char *symname);
212  
213  /* sumversion.c */
214  void get_src_version(const char *modname, char sum[], unsigned sumlen);
215  
216  /* from modpost.c */
217  extern bool target_is_big_endian;
218  extern bool host_is_big_endian;
219  char *read_text_file(const char *filename);
220  char *get_line(char **stringp);
221  void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);
222  
223  void __attribute__((format(printf, 2, 3)))
224  modpost_log(bool is_error, const char *fmt, ...);
225  
226  /*
227   * warn - show the given message, then let modpost continue running, still
228   *        allowing modpost to exit successfully. This should be used when
229   *        we still allow to generate vmlinux and modules.
230   *
231   * error - show the given message, then let modpost continue running, but fail
232   *         in the end. This should be used when we should stop building vmlinux
233   *         or modules, but we can continue running modpost to catch as many
234   *         issues as possible.
235   *
236   * fatal - show the given message, and bail out immediately. This should be
237   *         used when there is no point to continue running modpost.
238   */
239  #define warn(fmt, args...)	modpost_log(false, fmt, ##args)
240  #define error(fmt, args...)	modpost_log(true, fmt, ##args)
241  #define fatal(fmt, args...)	do { error(fmt, ##args); exit(1); } while (1)
242