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3e62da95 SM |
1 | /* unexec() support for Cygwin; |
2 | complete rewrite of xemacs Cygwin unexec() code | |
3 | ||
ab422c4d | 4 | Copyright (C) 2004-2013 Free Software Foundation, Inc. |
3e62da95 SM |
5 | |
6 | This file is part of GNU Emacs. | |
7 | ||
9ec0b715 | 8 | GNU Emacs is free software: you can redistribute it and/or modify |
3e62da95 | 9 | it under the terms of the GNU General Public License as published by |
9ec0b715 GM |
10 | the Free Software Foundation, either version 3 of the License, or |
11 | (at your option) any later version. | |
3e62da95 SM |
12 | |
13 | GNU Emacs is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
9ec0b715 | 19 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
3e62da95 SM |
20 | |
21 | #include <config.h> | |
ce701a33 | 22 | #include "unexec.h" |
406af475 | 23 | #include "lisp.h" |
ce701a33 | 24 | |
3e62da95 SM |
25 | #include <stdio.h> |
26 | #include <fcntl.h> | |
27 | #include <a.out.h> | |
28 | #include <unistd.h> | |
29 | #include <assert.h> | |
30 | ||
31 | #define DOTEXE ".exe" | |
32 | ||
a3454eed KB |
33 | extern void report_sheap_usage (int); |
34 | ||
3e62da95 SM |
35 | extern int bss_sbrk_did_unexec; |
36 | ||
a4579d33 KB |
37 | extern int __malloc_initialized; |
38 | ||
3e62da95 SM |
39 | /* emacs symbols that indicate where bss and data end for emacs internals */ |
40 | extern char my_endbss[]; | |
41 | extern char my_edata[]; | |
42 | ||
43 | /* | |
44 | ** header for Windows executable files | |
45 | */ | |
46 | typedef struct | |
47 | { | |
48 | FILHDR file_header; | |
49 | PEAOUTHDR file_optional_header; | |
50 | SCNHDR section_header[32]; | |
51 | } exe_header_t; | |
52 | ||
53 | int debug_unexcw = 0; | |
54 | ||
55 | /* | |
56 | ** Read the header from the executable into memory so we can more easily access it. | |
57 | */ | |
58 | static exe_header_t * | |
59 | read_exe_header (int fd, exe_header_t * exe_header_buffer) | |
60 | { | |
61 | int i; | |
62 | int ret; | |
63 | ||
64 | assert (fd >= 0); | |
65 | assert (exe_header_buffer != 0); | |
66 | ||
67 | ret = lseek (fd, 0L, SEEK_SET); | |
68 | assert (ret != -1); | |
69 | ||
70 | ret = | |
71 | read (fd, &exe_header_buffer->file_header, | |
72 | sizeof (exe_header_buffer->file_header)); | |
73 | assert (ret == sizeof (exe_header_buffer->file_header)); | |
74 | ||
75 | assert (exe_header_buffer->file_header.e_magic == 0x5a4d); | |
76 | assert (exe_header_buffer->file_header.nt_signature == 0x4550); | |
a3454eed KB |
77 | #ifdef __x86_64__ |
78 | assert (exe_header_buffer->file_header.f_magic == 0x8664); | |
79 | #else | |
3e62da95 | 80 | assert (exe_header_buffer->file_header.f_magic == 0x014c); |
a3454eed | 81 | #endif |
3e62da95 SM |
82 | assert (exe_header_buffer->file_header.f_nscns > 0); |
83 | assert (exe_header_buffer->file_header.f_nscns <= | |
84 | sizeof (exe_header_buffer->section_header) / | |
85 | sizeof (exe_header_buffer->section_header[0])); | |
86 | assert (exe_header_buffer->file_header.f_opthdr > 0); | |
87 | ||
88 | ret = | |
89 | read (fd, &exe_header_buffer->file_optional_header, | |
90 | sizeof (exe_header_buffer->file_optional_header)); | |
91 | assert (ret == sizeof (exe_header_buffer->file_optional_header)); | |
92 | ||
a3454eed KB |
93 | #ifdef __x86_64__ |
94 | assert (exe_header_buffer->file_optional_header.magic == 0x020b); | |
95 | #else | |
3e62da95 | 96 | assert (exe_header_buffer->file_optional_header.magic == 0x010b); |
a3454eed | 97 | #endif |
3e62da95 SM |
98 | |
99 | for (i = 0; i < exe_header_buffer->file_header.f_nscns; ++i) | |
100 | { | |
101 | ret = | |
102 | read (fd, &exe_header_buffer->section_header[i], | |
103 | sizeof (exe_header_buffer->section_header[i])); | |
104 | assert (ret == sizeof (exe_header_buffer->section_header[i])); | |
105 | } | |
106 | ||
107 | return (exe_header_buffer); | |
108 | } | |
109 | ||
110 | /* | |
111 | ** Fix the dumped emacs executable: | |
112 | ** | |
113 | ** - copy .data section data of interest from running executable into | |
114 | ** output .exe file | |
115 | ** | |
116 | ** - convert .bss section into an initialized data section (like | |
117 | ** .data) and copy .bss section data of interest from running | |
118 | ** executable into output .exe file | |
119 | */ | |
120 | static void | |
121 | fixup_executable (int fd) | |
122 | { | |
123 | exe_header_t exe_header_buffer; | |
124 | exe_header_t *exe_header; | |
125 | int i; | |
126 | int ret; | |
127 | int found_data = 0; | |
128 | int found_bss = 0; | |
129 | ||
130 | exe_header = read_exe_header (fd, &exe_header_buffer); | |
131 | assert (exe_header != 0); | |
132 | ||
133 | assert (exe_header->file_header.f_nscns > 0); | |
134 | for (i = 0; i < exe_header->file_header.f_nscns; ++i) | |
135 | { | |
136 | unsigned long start_address = | |
137 | exe_header->section_header[i].s_vaddr + | |
138 | exe_header->file_optional_header.ImageBase; | |
139 | unsigned long end_address = | |
140 | exe_header->section_header[i].s_vaddr + | |
141 | exe_header->file_optional_header.ImageBase + | |
142 | exe_header->section_header[i].s_paddr; | |
143 | if (debug_unexcw) | |
a3454eed | 144 | printf ("%8s start %#lx end %#lx\n", |
3e62da95 SM |
145 | exe_header->section_header[i].s_name, |
146 | start_address, end_address); | |
147 | if (my_edata >= (char *) start_address | |
148 | && my_edata < (char *) end_address) | |
149 | { | |
150 | /* data section */ | |
151 | ret = | |
152 | lseek (fd, (long) (exe_header->section_header[i].s_scnptr), | |
153 | SEEK_SET); | |
154 | assert (ret != -1); | |
155 | ret = | |
156 | write (fd, (char *) start_address, | |
157 | my_edata - (char *) start_address); | |
158 | assert (ret == my_edata - (char *) start_address); | |
159 | ++found_data; | |
160 | if (debug_unexcw) | |
a3454eed | 161 | printf (" .data, mem start %#lx mem length %d\n", |
3e62da95 SM |
162 | start_address, my_edata - (char *) start_address); |
163 | if (debug_unexcw) | |
164 | printf (" .data, file start %d file length %d\n", | |
165 | (int) exe_header->section_header[i].s_scnptr, | |
166 | (int) exe_header->section_header[i].s_paddr); | |
167 | } | |
168 | else if (my_endbss >= (char *) start_address | |
169 | && my_endbss < (char *) end_address) | |
170 | { | |
171 | /* bss section */ | |
172 | ++found_bss; | |
173 | if (exe_header->section_header[i].s_flags & 0x00000080) | |
174 | { | |
175 | /* convert uninitialized data section to initialized data section */ | |
176 | struct stat statbuf; | |
177 | ret = fstat (fd, &statbuf); | |
178 | assert (ret != -1); | |
179 | ||
180 | exe_header->section_header[i].s_flags &= ~0x00000080; | |
181 | exe_header->section_header[i].s_flags |= 0x00000040; | |
182 | ||
183 | exe_header->section_header[i].s_scnptr = | |
184 | (statbuf.st_size + | |
185 | exe_header->file_optional_header.FileAlignment) / | |
186 | exe_header->file_optional_header.FileAlignment * | |
187 | exe_header->file_optional_header.FileAlignment; | |
188 | ||
189 | exe_header->section_header[i].s_size = | |
190 | (exe_header->section_header[i].s_paddr + | |
191 | exe_header->file_optional_header.FileAlignment) / | |
192 | exe_header->file_optional_header.FileAlignment * | |
193 | exe_header->file_optional_header.FileAlignment; | |
194 | ||
cc98b684 DC |
195 | /* Make sure the generated bootstrap binary isn't |
196 | * sparse. NT doesn't use a file cache for sparse | |
197 | * executables, so if we bootstrap Emacs using a sparse | |
198 | * bootstrap-emacs.exe, bootstrap takes about twenty | |
199 | * times longer than it would otherwise. */ | |
200 | ||
201 | ret = posix_fallocate (fd, | |
202 | ( exe_header->section_header[i].s_scnptr + | |
203 | exe_header->section_header[i].s_size ), | |
204 | 1); | |
205 | ||
206 | assert (ret != -1); | |
207 | ||
3e62da95 SM |
208 | ret = |
209 | lseek (fd, | |
210 | (long) (exe_header->section_header[i].s_scnptr + | |
211 | exe_header->section_header[i].s_size - 1), | |
212 | SEEK_SET); | |
213 | assert (ret != -1); | |
214 | ret = write (fd, "", 1); | |
215 | assert (ret == 1); | |
216 | ||
217 | ret = | |
218 | lseek (fd, | |
219 | (long) ((char *) &exe_header->section_header[i] - | |
220 | (char *) exe_header), SEEK_SET); | |
221 | assert (ret != -1); | |
222 | ret = | |
223 | write (fd, &exe_header->section_header[i], | |
224 | sizeof (exe_header->section_header[i])); | |
225 | assert (ret == sizeof (exe_header->section_header[i])); | |
226 | if (debug_unexcw) | |
227 | printf (" seek to %ld, write %d\n", | |
228 | (long) ((char *) &exe_header->section_header[i] - | |
229 | (char *) exe_header), | |
230 | sizeof (exe_header->section_header[i])); | |
231 | } | |
232 | /* write initialized data section */ | |
233 | ret = | |
234 | lseek (fd, (long) (exe_header->section_header[i].s_scnptr), | |
235 | SEEK_SET); | |
236 | assert (ret != -1); | |
a4579d33 KB |
237 | /* force the dumped emacs to reinitialize malloc */ |
238 | __malloc_initialized = 0; | |
3e62da95 SM |
239 | ret = |
240 | write (fd, (char *) start_address, | |
241 | my_endbss - (char *) start_address); | |
a4579d33 | 242 | __malloc_initialized = 1; |
3e62da95 SM |
243 | assert (ret == (my_endbss - (char *) start_address)); |
244 | if (debug_unexcw) | |
a3454eed | 245 | printf (" .bss, mem start %#lx mem length %d\n", |
3e62da95 SM |
246 | start_address, my_endbss - (char *) start_address); |
247 | if (debug_unexcw) | |
248 | printf (" .bss, file start %d file length %d\n", | |
249 | (int) exe_header->section_header[i].s_scnptr, | |
250 | (int) exe_header->section_header[i].s_paddr); | |
251 | } | |
252 | } | |
253 | assert (found_bss == 1); | |
254 | assert (found_data == 1); | |
255 | } | |
256 | ||
257 | /* | |
258 | ** Windows likes .exe suffixes on executables. | |
259 | */ | |
260 | static char * | |
261 | add_exe_suffix_if_necessary (const char *name, char *modified) | |
262 | { | |
263 | int i = strlen (name); | |
264 | if (i <= (sizeof (DOTEXE) - 1)) | |
265 | { | |
266 | sprintf (modified, "%s%s", name, DOTEXE); | |
267 | } | |
268 | else if (!strcasecmp (name + i - (sizeof (DOTEXE) - 1), DOTEXE)) | |
269 | { | |
270 | strcpy (modified, name); | |
271 | } | |
272 | else | |
273 | { | |
274 | sprintf (modified, "%s%s", name, DOTEXE); | |
275 | } | |
276 | return (modified); | |
277 | } | |
278 | ||
381259ef | 279 | void |
dd5ecd6b | 280 | unexec (const char *outfile, const char *infile) |
3e62da95 SM |
281 | { |
282 | char infile_buffer[FILENAME_MAX]; | |
283 | char outfile_buffer[FILENAME_MAX]; | |
284 | int fd_in; | |
285 | int fd_out; | |
286 | int ret; | |
287 | int ret2; | |
288 | ||
289 | if (bss_sbrk_did_unexec) | |
290 | { | |
291 | /* can only dump once */ | |
60a294e2 | 292 | printf ("You can only dump Emacs once on this platform.\n"); |
fffe2e14 | 293 | return; |
3e62da95 SM |
294 | } |
295 | ||
296 | report_sheap_usage (1); | |
297 | ||
298 | infile = add_exe_suffix_if_necessary (infile, infile_buffer); | |
299 | outfile = add_exe_suffix_if_necessary (outfile, outfile_buffer); | |
300 | ||
406af475 | 301 | fd_in = emacs_open (infile, O_RDONLY | O_BINARY, 0); |
3e62da95 | 302 | assert (fd_in >= 0); |
406af475 | 303 | fd_out = emacs_open (outfile, O_RDWR | O_TRUNC | O_CREAT | O_BINARY, 0755); |
3e62da95 SM |
304 | assert (fd_out >= 0); |
305 | for (;;) | |
306 | { | |
307 | char buffer[4096]; | |
308 | ret = read (fd_in, buffer, sizeof (buffer)); | |
309 | if (ret == 0) | |
310 | { | |
311 | /* eof */ | |
312 | break; | |
313 | } | |
314 | assert (ret > 0); | |
315 | /* data */ | |
316 | ret2 = write (fd_out, buffer, ret); | |
317 | assert (ret2 == ret); | |
318 | } | |
bacba3c2 | 319 | ret = emacs_close (fd_in); |
3e62da95 SM |
320 | assert (ret == 0); |
321 | ||
322 | bss_sbrk_did_unexec = 1; | |
323 | fixup_executable (fd_out); | |
324 | bss_sbrk_did_unexec = 0; | |
325 | ||
bacba3c2 | 326 | ret = emacs_close (fd_out); |
3e62da95 | 327 | assert (ret == 0); |
3e62da95 | 328 | } |