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25#include <sys/mman.h>
26#include <sys/stat.h>
27#include <sys/types.h>
28
29#include <byteswap.h>
30#include <elf.h>
31#include <errno.h>
32#include <fcntl.h>
33#include <inttypes.h>
34#include <stdarg.h>
35#include <stdbool.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <string.h>
39#include <unistd.h>
40
41
42#ifndef SHT_GNU_ATTRIBUTES
43# define SHT_GNU_ATTRIBUTES 0x6ffffff5
44#endif
45#ifndef SHT_MIPS_ABIFLAGS
46# define SHT_MIPS_ABIFLAGS 0x7000002a
47#endif
48
49enum {
50 ABI_O32 = (1 << 0),
51 ABI_N32 = (1 << 1),
52 ABI_N64 = (1 << 2),
53
54 ABI_ALL = ABI_O32 | ABI_N32 | ABI_N64,
55};
56
57
58static struct {
59 const char *name;
60 const char *offset_name;
61 unsigned int abis;
62} vdso_symbols[] = {
63 { "__vdso_sigreturn", "off_sigreturn", ABI_O32 },
64 { "__vdso_rt_sigreturn", "off_rt_sigreturn", ABI_ALL },
65 {}
66};
67
68static const char *program_name;
69static const char *vdso_name;
70static unsigned char elf_class;
71static unsigned int elf_abi;
72static bool need_swap;
73static FILE *out_file;
74
75#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
76# define HOST_ORDER ELFDATA2LSB
77#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
78# define HOST_ORDER ELFDATA2MSB
79#endif
80
81#define BUILD_SWAP(bits) \
82 static uint##bits##_t swap_uint##bits(uint##bits##_t val) \
83 { \
84 return need_swap ? bswap_##bits(val) : val; \
85 }
86
87BUILD_SWAP(16)
88BUILD_SWAP(32)
89BUILD_SWAP(64)
90
91#define __FUNC(name, bits) name##bits
92#define _FUNC(name, bits) __FUNC(name, bits)
93#define FUNC(name) _FUNC(name, ELF_BITS)
94
95#define __ELF(x, bits) Elf##bits##_##x
96#define _ELF(x, bits) __ELF(x, bits)
97#define ELF(x) _ELF(x, ELF_BITS)
98
99
100
101
102
103
104#define ELF_BITS 64
105#include "genvdso.h"
106#undef ELF_BITS
107
108#define ELF_BITS 32
109#include "genvdso.h"
110#undef ELF_BITS
111
112static void *map_vdso(const char *path, size_t *_size)
113{
114 int fd;
115 struct stat stat;
116 void *addr;
117 const Elf32_Ehdr *ehdr;
118
119 fd = open(path, O_RDWR);
120 if (fd < 0) {
121 fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
122 path, strerror(errno));
123 return NULL;
124 }
125
126 if (fstat(fd, &stat) != 0) {
127 fprintf(stderr, "%s: Failed to stat '%s': %s\n", program_name,
128 path, strerror(errno));
129 return NULL;
130 }
131
132 addr = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
133 0);
134 if (addr == MAP_FAILED) {
135 fprintf(stderr, "%s: Failed to map '%s': %s\n", program_name,
136 path, strerror(errno));
137 return NULL;
138 }
139
140
141 ehdr = addr;
142
143 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) {
144 fprintf(stderr, "%s: '%s' is not an ELF file\n", program_name,
145 path);
146 return NULL;
147 }
148
149 elf_class = ehdr->e_ident[EI_CLASS];
150 switch (elf_class) {
151 case ELFCLASS32:
152 case ELFCLASS64:
153 break;
154 default:
155 fprintf(stderr, "%s: '%s' has invalid ELF class\n",
156 program_name, path);
157 return NULL;
158 }
159
160 switch (ehdr->e_ident[EI_DATA]) {
161 case ELFDATA2LSB:
162 case ELFDATA2MSB:
163 need_swap = ehdr->e_ident[EI_DATA] != HOST_ORDER;
164 break;
165 default:
166 fprintf(stderr, "%s: '%s' has invalid ELF data order\n",
167 program_name, path);
168 return NULL;
169 }
170
171 if (swap_uint16(ehdr->e_machine) != EM_MIPS) {
172 fprintf(stderr,
173 "%s: '%s' has invalid ELF machine (expected EM_MIPS)\n",
174 program_name, path);
175 return NULL;
176 } else if (swap_uint16(ehdr->e_type) != ET_DYN) {
177 fprintf(stderr,
178 "%s: '%s' has invalid ELF type (expected ET_DYN)\n",
179 program_name, path);
180 return NULL;
181 }
182
183 *_size = stat.st_size;
184 return addr;
185}
186
187static bool patch_vdso(const char *path, void *vdso)
188{
189 if (elf_class == ELFCLASS64)
190 return patch_vdso64(path, vdso);
191 else
192 return patch_vdso32(path, vdso);
193}
194
195static bool get_symbols(const char *path, void *vdso)
196{
197 if (elf_class == ELFCLASS64)
198 return get_symbols64(path, vdso);
199 else
200 return get_symbols32(path, vdso);
201}
202
203int main(int argc, char **argv)
204{
205 const char *dbg_vdso_path, *vdso_path, *out_path;
206 void *dbg_vdso, *vdso;
207 size_t dbg_vdso_size, vdso_size, i;
208
209 program_name = argv[0];
210
211 if (argc < 4 || argc > 5) {
212 fprintf(stderr,
213 "Usage: %s <debug VDSO> <stripped VDSO> <output file> [<name>]\n",
214 program_name);
215 return EXIT_FAILURE;
216 }
217
218 dbg_vdso_path = argv[1];
219 vdso_path = argv[2];
220 out_path = argv[3];
221 vdso_name = (argc > 4) ? argv[4] : "";
222
223 dbg_vdso = map_vdso(dbg_vdso_path, &dbg_vdso_size);
224 if (!dbg_vdso)
225 return EXIT_FAILURE;
226
227 vdso = map_vdso(vdso_path, &vdso_size);
228 if (!vdso)
229 return EXIT_FAILURE;
230
231
232 if (!patch_vdso(dbg_vdso_path, dbg_vdso))
233 return EXIT_FAILURE;
234 if (!patch_vdso(vdso_path, vdso))
235 return EXIT_FAILURE;
236
237 if (msync(dbg_vdso, dbg_vdso_size, MS_SYNC) != 0) {
238 fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
239 dbg_vdso_path, strerror(errno));
240 return EXIT_FAILURE;
241 } else if (msync(vdso, vdso_size, MS_SYNC) != 0) {
242 fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
243 vdso_path, strerror(errno));
244 return EXIT_FAILURE;
245 }
246
247 out_file = fopen(out_path, "w");
248 if (!out_file) {
249 fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
250 out_path, strerror(errno));
251 return EXIT_FAILURE;
252 }
253
254 fprintf(out_file, "/* Automatically generated - do not edit */\n");
255 fprintf(out_file, "#include <linux/linkage.h>\n");
256 fprintf(out_file, "#include <linux/mm.h>\n");
257 fprintf(out_file, "#include <asm/vdso.h>\n");
258
259
260 fprintf(out_file,
261 "static unsigned char vdso_data[PAGE_ALIGN(%zu)] __page_aligned_data = {\n\t",
262 vdso_size);
263 for (i = 0; i < vdso_size; i++) {
264 if (!(i % 10))
265 fprintf(out_file, "\n\t");
266 fprintf(out_file, "0x%02x, ", ((unsigned char *)vdso)[i]);
267 }
268 fprintf(out_file, "\n};\n");
269
270
271 fprintf(out_file,
272 "static struct page *vdso_pages[PAGE_ALIGN(%zu) / PAGE_SIZE];\n",
273 vdso_size);
274
275 fprintf(out_file, "struct mips_vdso_image vdso_image%s%s = {\n",
276 (vdso_name[0]) ? "_" : "", vdso_name);
277 fprintf(out_file, "\t.data = vdso_data,\n");
278 fprintf(out_file, "\t.size = PAGE_ALIGN(%zu),\n", vdso_size);
279 fprintf(out_file, "\t.mapping = {\n");
280 fprintf(out_file, "\t\t.name = \"[vdso]\",\n");
281 fprintf(out_file, "\t\t.pages = vdso_pages,\n");
282 fprintf(out_file, "\t},\n");
283
284
285 if (!get_symbols(dbg_vdso_path, dbg_vdso)) {
286 unlink(out_path);
287 return EXIT_FAILURE;
288 }
289
290 fprintf(out_file, "};\n");
291
292 return EXIT_SUCCESS;
293}
294
