Commit | Line | Data |
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dcfdbac7 JB |
1 | /* Unexec for HP 9000 Series 800 machines. |
2 | Bob Desinger <hpsemc!bd@hplabs.hp.com> | |
3 | ||
4 | Note that the GNU project considers support for HP operation a | |
5 | peripheral activity which should not be allowed to divert effort | |
6 | from development of the GNU system. Changes in this code will be | |
7 | installed when users send them in, but aside from that we don't | |
8 | plan to think about it, or about whether other Emacs maintenance | |
9 | might break it. | |
10 | ||
11 | ||
12 | Unexec creates a copy of the old a.out file, and replaces the old data | |
13 | area with the current data area. When the new file is executed, the | |
14 | process will see the same data structures and data values that the | |
15 | original process had when unexec was called. | |
16 | ||
17 | Unlike other versions of unexec, this one copies symbol table and | |
18 | debug information to the new a.out file. Thus, the new a.out file | |
19 | may be debugged with symbolic debuggers. | |
20 | ||
21 | If you fix any bugs in this, I'd like to incorporate your fixes. | |
22 | Send them to uunet!hpda!hpsemc!jmorris or jmorris%hpsemc@hplabs.HP.COM. | |
23 | ||
24 | CAVEATS: | |
25 | This routine saves the current value of all static and external | |
26 | variables. This means that any data structure that needs to be | |
27 | initialized must be explicitly reset. Variables will not have their | |
28 | expected default values. | |
29 | ||
30 | Unfortunately, the HP-UX signal handler has internal initialization | |
31 | flags which are not explicitly reset. Thus, for signals to work in | |
32 | conjunction with this routine, the following code must executed when | |
33 | the new process starts up. | |
34 | ||
3f8a3241 | 35 | void _sigreturn (); |
dcfdbac7 | 36 | ... |
3f8a3241 | 37 | sigsetreturn (_sigreturn); |
dcfdbac7 JB |
38 | */ |
39 | \f | |
40 | #include <stdio.h> | |
41 | #include <fcntl.h> | |
42 | #include <errno.h> | |
43 | ||
44 | #include <a.out.h> | |
45 | ||
b8a0abf2 RS |
46 | #ifdef emacs |
47 | #include <config.h> | |
48 | #endif | |
49 | ||
50 | #ifdef HPUX_USE_SHLIBS | |
51 | #include <dl.h> | |
52 | #endif | |
53 | ||
54 | /* brk value to restore, stored as a global. | |
55 | This is really used only if we used shared libraries. */ | |
56 | static long brk_on_dump = 0; | |
57 | ||
58 | /* Called from main, if we use shared libraries. */ | |
59 | int | |
60 | run_time_remap (ignored) | |
61 | char *ignored; | |
62 | { | |
63 | brk (brk_on_dump); | |
64 | } | |
65 | ||
3f8a3241 RS |
66 | #define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1)) /* n is power of 2 */ |
67 | #define min(x,y) (((x) < (y)) ? (x) : (y)) | |
dcfdbac7 JB |
68 | |
69 | ||
70 | /* Create a new a.out file, same as old but with current data space */ | |
71 | ||
3f8a3241 | 72 | unexec (new_name, old_name, new_end_of_text, dummy1, dummy2) |
dcfdbac7 JB |
73 | char new_name[]; /* name of the new a.out file to be created */ |
74 | char old_name[]; /* name of the old a.out file */ | |
75 | char *new_end_of_text; /* ptr to new edata/etext; NOT USED YET */ | |
76 | int dummy1, dummy2; /* not used by emacs */ | |
77 | { | |
78 | int old, new; | |
79 | int old_size, new_size; | |
80 | struct header hdr; | |
81 | struct som_exec_auxhdr auxhdr; | |
d427b66a | 82 | long i; |
dcfdbac7 JB |
83 | |
84 | /* For the greatest flexibility, should create a temporary file in | |
85 | the same directory as the new file. When everything is complete, | |
86 | rename the temp file to the new name. | |
87 | This way, a program could update its own a.out file even while | |
88 | it is still executing. If problems occur, everything is still | |
89 | intact. NOT implemented. */ | |
90 | ||
91 | /* Open the input and output a.out files */ | |
3f8a3241 | 92 | old = open (old_name, O_RDONLY); |
dcfdbac7 | 93 | if (old < 0) |
3f8a3241 RS |
94 | { perror (old_name); exit (1); } |
95 | new = open (new_name, O_CREAT|O_RDWR|O_TRUNC, 0777); | |
dcfdbac7 | 96 | if (new < 0) |
3f8a3241 | 97 | { perror (new_name); exit (1); } |
dcfdbac7 JB |
98 | |
99 | /* Read the old headers */ | |
3f8a3241 | 100 | read_header (old, &hdr, &auxhdr); |
b8a0abf2 RS |
101 | |
102 | brk_on_dump = sbrk (0); | |
dcfdbac7 JB |
103 | |
104 | /* Decide how large the new and old data areas are */ | |
105 | old_size = auxhdr.exec_dsize; | |
d427b66a JB |
106 | /* I suspect these two statements are separate |
107 | to avoid a compiler bug in hpux version 8. */ | |
108 | i = sbrk (0); | |
109 | new_size = i - auxhdr.exec_dmem; | |
dcfdbac7 JB |
110 | |
111 | /* Copy the old file to the new, up to the data space */ | |
3f8a3241 RS |
112 | lseek (old, 0, 0); |
113 | copy_file (old, new, auxhdr.exec_dfile); | |
dcfdbac7 JB |
114 | |
115 | /* Skip the old data segment and write a new one */ | |
3f8a3241 RS |
116 | lseek (old, old_size, 1); |
117 | save_data_space (new, &hdr, &auxhdr, new_size); | |
dcfdbac7 JB |
118 | |
119 | /* Copy the rest of the file */ | |
3f8a3241 | 120 | copy_rest (old, new); |
dcfdbac7 JB |
121 | |
122 | /* Update file pointers since we probably changed size of data area */ | |
3f8a3241 | 123 | update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size); |
dcfdbac7 JB |
124 | |
125 | /* Save the modified header */ | |
3f8a3241 | 126 | write_header (new, &hdr, &auxhdr); |
dcfdbac7 JB |
127 | |
128 | /* Close the binary file */ | |
3f8a3241 RS |
129 | close (old); |
130 | close (new); | |
f3bca33c | 131 | return 0; |
dcfdbac7 JB |
132 | } |
133 | ||
134 | /* Save current data space in the file, update header. */ | |
135 | ||
3f8a3241 | 136 | save_data_space (file, hdr, auxhdr, size) |
dcfdbac7 JB |
137 | int file; |
138 | struct header *hdr; | |
139 | struct som_exec_auxhdr *auxhdr; | |
140 | int size; | |
141 | { | |
142 | /* Write the entire data space out to the file */ | |
3f8a3241 RS |
143 | if (write (file, auxhdr->exec_dmem, size) != size) |
144 | { perror ("Can't save new data space"); exit (1); } | |
dcfdbac7 JB |
145 | |
146 | /* Update the header to reflect the new data size */ | |
147 | auxhdr->exec_dsize = size; | |
148 | auxhdr->exec_bsize = 0; | |
149 | } | |
150 | ||
151 | /* Update the values of file pointers when something is inserted. */ | |
152 | ||
3f8a3241 | 153 | update_file_ptrs (file, hdr, auxhdr, location, offset) |
dcfdbac7 JB |
154 | int file; |
155 | struct header *hdr; | |
156 | struct som_exec_auxhdr *auxhdr; | |
157 | unsigned int location; | |
158 | int offset; | |
159 | { | |
160 | struct subspace_dictionary_record subspace; | |
161 | int i; | |
162 | ||
163 | /* Increase the overall size of the module */ | |
164 | hdr->som_length += offset; | |
165 | ||
166 | /* Update the various file pointers in the header */ | |
167 | #define update(ptr) if (ptr > location) ptr = ptr + offset | |
3f8a3241 RS |
168 | update (hdr->aux_header_location); |
169 | update (hdr->space_strings_location); | |
170 | update (hdr->init_array_location); | |
171 | update (hdr->compiler_location); | |
172 | update (hdr->symbol_location); | |
173 | update (hdr->fixup_request_location); | |
174 | update (hdr->symbol_strings_location); | |
175 | update (hdr->unloadable_sp_location); | |
176 | update (auxhdr->exec_tfile); | |
177 | update (auxhdr->exec_dfile); | |
dcfdbac7 JB |
178 | |
179 | /* Do for each subspace dictionary entry */ | |
3f8a3241 | 180 | lseek (file, hdr->subspace_location, 0); |
dcfdbac7 JB |
181 | for (i = 0; i < hdr->subspace_total; i++) |
182 | { | |
3f8a3241 RS |
183 | if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace)) |
184 | { perror ("Can't read subspace record"); exit (1); } | |
dcfdbac7 JB |
185 | |
186 | /* If subspace has a file location, update it */ | |
187 | if (subspace.initialization_length > 0 | |
188 | && subspace.file_loc_init_value > location) | |
189 | { | |
190 | subspace.file_loc_init_value += offset; | |
3f8a3241 RS |
191 | lseek (file, -sizeof (subspace), 1); |
192 | if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace)) | |
193 | { perror ("Can't update subspace record"); exit (1); } | |
dcfdbac7 JB |
194 | } |
195 | } | |
196 | ||
197 | /* Do for each initialization pointer record */ | |
198 | /* (I don't think it applies to executable files, only relocatables) */ | |
199 | #undef update | |
200 | } | |
201 | ||
202 | /* Read in the header records from an a.out file. */ | |
203 | ||
3f8a3241 | 204 | read_header (file, hdr, auxhdr) |
dcfdbac7 JB |
205 | int file; |
206 | struct header *hdr; | |
207 | struct som_exec_auxhdr *auxhdr; | |
208 | { | |
209 | ||
210 | /* Read the header in */ | |
3f8a3241 RS |
211 | lseek (file, 0, 0); |
212 | if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
213 | { perror ("Couldn't read header from a.out file"); exit (1); } | |
dcfdbac7 JB |
214 | |
215 | if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC | |
216 | && hdr->a_magic != DEMAND_MAGIC) | |
217 | { | |
3f8a3241 RS |
218 | fprintf (stderr, "a.out file doesn't have legal magic number\n"); |
219 | exit (1); | |
dcfdbac7 JB |
220 | } |
221 | ||
3f8a3241 RS |
222 | lseek (file, hdr->aux_header_location, 0); |
223 | if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
dcfdbac7 | 224 | { |
3f8a3241 RS |
225 | perror ("Couldn't read auxiliary header from a.out file"); |
226 | exit (1); | |
dcfdbac7 JB |
227 | } |
228 | } | |
229 | ||
230 | /* Write out the header records into an a.out file. */ | |
231 | ||
3f8a3241 | 232 | write_header (file, hdr, auxhdr) |
dcfdbac7 JB |
233 | int file; |
234 | struct header *hdr; | |
235 | struct som_exec_auxhdr *auxhdr; | |
236 | { | |
237 | /* Update the checksum */ | |
3f8a3241 | 238 | hdr->checksum = calculate_checksum (hdr); |
dcfdbac7 JB |
239 | |
240 | /* Write the header back into the a.out file */ | |
3f8a3241 RS |
241 | lseek (file, 0, 0); |
242 | if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
243 | { perror ("Couldn't write header to a.out file"); exit (1); } | |
244 | lseek (file, hdr->aux_header_location, 0); | |
245 | if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
246 | { perror ("Couldn't write auxiliary header to a.out file"); exit (1); } | |
dcfdbac7 JB |
247 | } |
248 | ||
249 | /* Calculate the checksum of a SOM header record. */ | |
250 | ||
3f8a3241 | 251 | calculate_checksum (hdr) |
dcfdbac7 JB |
252 | struct header *hdr; |
253 | { | |
254 | int checksum, i, *ptr; | |
255 | ||
256 | checksum = 0; ptr = (int *) hdr; | |
257 | ||
3f8a3241 | 258 | for (i = 0; i < sizeof (*hdr) / sizeof (int) - 1; i++) |
dcfdbac7 JB |
259 | checksum ^= ptr[i]; |
260 | ||
3f8a3241 | 261 | return (checksum); |
dcfdbac7 JB |
262 | } |
263 | ||
264 | /* Copy size bytes from the old file to the new one. */ | |
265 | ||
3f8a3241 | 266 | copy_file (old, new, size) |
dcfdbac7 JB |
267 | int new, old; |
268 | int size; | |
269 | { | |
270 | int len; | |
b8a0abf2 | 271 | int buffer[8192]; /* word aligned will be faster */ |
dcfdbac7 JB |
272 | |
273 | for (; size > 0; size -= len) | |
274 | { | |
3f8a3241 RS |
275 | len = min (size, sizeof (buffer)); |
276 | if (read (old, buffer, len) != len) | |
277 | { perror ("Read failure on a.out file"); exit (1); } | |
278 | if (write (new, buffer, len) != len) | |
279 | { perror ("Write failure in a.out file"); exit (1); } | |
dcfdbac7 JB |
280 | } |
281 | } | |
282 | ||
283 | /* Copy the rest of the file, up to EOF. */ | |
284 | ||
3f8a3241 | 285 | copy_rest (old, new) |
dcfdbac7 JB |
286 | int new, old; |
287 | { | |
288 | int buffer[4096]; | |
289 | int len; | |
290 | ||
291 | /* Copy bytes until end of file or error */ | |
3f8a3241 RS |
292 | while ((len = read (old, buffer, sizeof (buffer))) > 0) |
293 | if (write (new, buffer, len) != len) break; | |
dcfdbac7 JB |
294 | |
295 | if (len != 0) | |
3f8a3241 | 296 | { perror ("Unable to copy the rest of the file"); exit (1); } |
dcfdbac7 JB |
297 | } |
298 | ||
299 | #ifdef DEBUG | |
3f8a3241 | 300 | display_header (hdr, auxhdr) |
dcfdbac7 JB |
301 | struct header *hdr; |
302 | struct som_exec_auxhdr *auxhdr; | |
303 | { | |
304 | /* Display the header information (debug) */ | |
3f8a3241 RS |
305 | printf ("\n\nFILE HEADER\n"); |
306 | printf ("magic number %d \n", hdr->a_magic); | |
307 | printf ("text loc %.8x size %d \n", auxhdr->exec_tmem, auxhdr->exec_tsize); | |
308 | printf ("data loc %.8x size %d \n", auxhdr->exec_dmem, auxhdr->exec_dsize); | |
309 | printf ("entry %x \n", auxhdr->exec_entry); | |
310 | printf ("Bss segment size %u\n", auxhdr->exec_bsize); | |
311 | printf ("\n"); | |
312 | printf ("data file loc %d size %d\n", | |
313 | auxhdr->exec_dfile, auxhdr->exec_dsize); | |
314 | printf ("som_length %d\n", hdr->som_length); | |
315 | printf ("unloadable sploc %d size %d\n", | |
316 | hdr->unloadable_sp_location, hdr->unloadable_sp_size); | |
dcfdbac7 JB |
317 | } |
318 | #endif /* DEBUG */ |