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 | ||
dad1bbe2 | 66 | #undef roundup |
3f8a3241 RS |
67 | #define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1)) /* n is power of 2 */ |
68 | #define min(x,y) (((x) < (y)) ? (x) : (y)) | |
dcfdbac7 JB |
69 | |
70 | ||
71 | /* Create a new a.out file, same as old but with current data space */ | |
72 | ||
3f8a3241 | 73 | unexec (new_name, old_name, new_end_of_text, dummy1, dummy2) |
dcfdbac7 JB |
74 | char new_name[]; /* name of the new a.out file to be created */ |
75 | char old_name[]; /* name of the old a.out file */ | |
76 | char *new_end_of_text; /* ptr to new edata/etext; NOT USED YET */ | |
77 | int dummy1, dummy2; /* not used by emacs */ | |
78 | { | |
79 | int old, new; | |
80 | int old_size, new_size; | |
81 | struct header hdr; | |
82 | struct som_exec_auxhdr auxhdr; | |
d427b66a | 83 | long i; |
dcfdbac7 JB |
84 | |
85 | /* For the greatest flexibility, should create a temporary file in | |
86 | the same directory as the new file. When everything is complete, | |
87 | rename the temp file to the new name. | |
88 | This way, a program could update its own a.out file even while | |
89 | it is still executing. If problems occur, everything is still | |
90 | intact. NOT implemented. */ | |
91 | ||
92 | /* Open the input and output a.out files */ | |
3f8a3241 | 93 | old = open (old_name, O_RDONLY); |
dcfdbac7 | 94 | if (old < 0) |
3f8a3241 RS |
95 | { perror (old_name); exit (1); } |
96 | new = open (new_name, O_CREAT|O_RDWR|O_TRUNC, 0777); | |
dcfdbac7 | 97 | if (new < 0) |
3f8a3241 | 98 | { perror (new_name); exit (1); } |
dcfdbac7 JB |
99 | |
100 | /* Read the old headers */ | |
3f8a3241 | 101 | read_header (old, &hdr, &auxhdr); |
b8a0abf2 RS |
102 | |
103 | brk_on_dump = sbrk (0); | |
dcfdbac7 JB |
104 | |
105 | /* Decide how large the new and old data areas are */ | |
106 | old_size = auxhdr.exec_dsize; | |
d427b66a JB |
107 | /* I suspect these two statements are separate |
108 | to avoid a compiler bug in hpux version 8. */ | |
109 | i = sbrk (0); | |
110 | new_size = i - auxhdr.exec_dmem; | |
dcfdbac7 JB |
111 | |
112 | /* Copy the old file to the new, up to the data space */ | |
3f8a3241 RS |
113 | lseek (old, 0, 0); |
114 | copy_file (old, new, auxhdr.exec_dfile); | |
dcfdbac7 JB |
115 | |
116 | /* Skip the old data segment and write a new one */ | |
3f8a3241 RS |
117 | lseek (old, old_size, 1); |
118 | save_data_space (new, &hdr, &auxhdr, new_size); | |
dcfdbac7 JB |
119 | |
120 | /* Copy the rest of the file */ | |
3f8a3241 | 121 | copy_rest (old, new); |
dcfdbac7 JB |
122 | |
123 | /* Update file pointers since we probably changed size of data area */ | |
3f8a3241 | 124 | update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size); |
dcfdbac7 JB |
125 | |
126 | /* Save the modified header */ | |
3f8a3241 | 127 | write_header (new, &hdr, &auxhdr); |
dcfdbac7 JB |
128 | |
129 | /* Close the binary file */ | |
3f8a3241 RS |
130 | close (old); |
131 | close (new); | |
f3bca33c | 132 | return 0; |
dcfdbac7 JB |
133 | } |
134 | ||
135 | /* Save current data space in the file, update header. */ | |
136 | ||
3f8a3241 | 137 | save_data_space (file, hdr, auxhdr, size) |
dcfdbac7 JB |
138 | int file; |
139 | struct header *hdr; | |
140 | struct som_exec_auxhdr *auxhdr; | |
141 | int size; | |
142 | { | |
143 | /* Write the entire data space out to the file */ | |
3f8a3241 RS |
144 | if (write (file, auxhdr->exec_dmem, size) != size) |
145 | { perror ("Can't save new data space"); exit (1); } | |
dcfdbac7 JB |
146 | |
147 | /* Update the header to reflect the new data size */ | |
148 | auxhdr->exec_dsize = size; | |
149 | auxhdr->exec_bsize = 0; | |
150 | } | |
151 | ||
152 | /* Update the values of file pointers when something is inserted. */ | |
153 | ||
3f8a3241 | 154 | update_file_ptrs (file, hdr, auxhdr, location, offset) |
dcfdbac7 JB |
155 | int file; |
156 | struct header *hdr; | |
157 | struct som_exec_auxhdr *auxhdr; | |
158 | unsigned int location; | |
159 | int offset; | |
160 | { | |
161 | struct subspace_dictionary_record subspace; | |
162 | int i; | |
163 | ||
164 | /* Increase the overall size of the module */ | |
165 | hdr->som_length += offset; | |
166 | ||
167 | /* Update the various file pointers in the header */ | |
168 | #define update(ptr) if (ptr > location) ptr = ptr + offset | |
3f8a3241 RS |
169 | update (hdr->aux_header_location); |
170 | update (hdr->space_strings_location); | |
171 | update (hdr->init_array_location); | |
172 | update (hdr->compiler_location); | |
173 | update (hdr->symbol_location); | |
174 | update (hdr->fixup_request_location); | |
175 | update (hdr->symbol_strings_location); | |
176 | update (hdr->unloadable_sp_location); | |
177 | update (auxhdr->exec_tfile); | |
178 | update (auxhdr->exec_dfile); | |
dcfdbac7 JB |
179 | |
180 | /* Do for each subspace dictionary entry */ | |
3f8a3241 | 181 | lseek (file, hdr->subspace_location, 0); |
dcfdbac7 JB |
182 | for (i = 0; i < hdr->subspace_total; i++) |
183 | { | |
3f8a3241 RS |
184 | if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace)) |
185 | { perror ("Can't read subspace record"); exit (1); } | |
dcfdbac7 JB |
186 | |
187 | /* If subspace has a file location, update it */ | |
188 | if (subspace.initialization_length > 0 | |
189 | && subspace.file_loc_init_value > location) | |
190 | { | |
191 | subspace.file_loc_init_value += offset; | |
3f8a3241 RS |
192 | lseek (file, -sizeof (subspace), 1); |
193 | if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace)) | |
194 | { perror ("Can't update subspace record"); exit (1); } | |
dcfdbac7 JB |
195 | } |
196 | } | |
197 | ||
198 | /* Do for each initialization pointer record */ | |
199 | /* (I don't think it applies to executable files, only relocatables) */ | |
200 | #undef update | |
201 | } | |
202 | ||
203 | /* Read in the header records from an a.out file. */ | |
204 | ||
3f8a3241 | 205 | read_header (file, hdr, auxhdr) |
dcfdbac7 JB |
206 | int file; |
207 | struct header *hdr; | |
208 | struct som_exec_auxhdr *auxhdr; | |
209 | { | |
210 | ||
211 | /* Read the header in */ | |
3f8a3241 RS |
212 | lseek (file, 0, 0); |
213 | if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
214 | { perror ("Couldn't read header from a.out file"); exit (1); } | |
dcfdbac7 JB |
215 | |
216 | if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC | |
217 | && hdr->a_magic != DEMAND_MAGIC) | |
218 | { | |
3f8a3241 RS |
219 | fprintf (stderr, "a.out file doesn't have legal magic number\n"); |
220 | exit (1); | |
dcfdbac7 JB |
221 | } |
222 | ||
3f8a3241 RS |
223 | lseek (file, hdr->aux_header_location, 0); |
224 | if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
dcfdbac7 | 225 | { |
3f8a3241 RS |
226 | perror ("Couldn't read auxiliary header from a.out file"); |
227 | exit (1); | |
dcfdbac7 JB |
228 | } |
229 | } | |
230 | ||
231 | /* Write out the header records into an a.out file. */ | |
232 | ||
3f8a3241 | 233 | write_header (file, hdr, auxhdr) |
dcfdbac7 JB |
234 | int file; |
235 | struct header *hdr; | |
236 | struct som_exec_auxhdr *auxhdr; | |
237 | { | |
238 | /* Update the checksum */ | |
3f8a3241 | 239 | hdr->checksum = calculate_checksum (hdr); |
dcfdbac7 JB |
240 | |
241 | /* Write the header back into the a.out file */ | |
3f8a3241 RS |
242 | lseek (file, 0, 0); |
243 | if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
244 | { perror ("Couldn't write header to a.out file"); exit (1); } | |
245 | lseek (file, hdr->aux_header_location, 0); | |
246 | if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
247 | { perror ("Couldn't write auxiliary header to a.out file"); exit (1); } | |
dcfdbac7 JB |
248 | } |
249 | ||
250 | /* Calculate the checksum of a SOM header record. */ | |
251 | ||
3f8a3241 | 252 | calculate_checksum (hdr) |
dcfdbac7 JB |
253 | struct header *hdr; |
254 | { | |
255 | int checksum, i, *ptr; | |
256 | ||
257 | checksum = 0; ptr = (int *) hdr; | |
258 | ||
3f8a3241 | 259 | for (i = 0; i < sizeof (*hdr) / sizeof (int) - 1; i++) |
dcfdbac7 JB |
260 | checksum ^= ptr[i]; |
261 | ||
3f8a3241 | 262 | return (checksum); |
dcfdbac7 JB |
263 | } |
264 | ||
265 | /* Copy size bytes from the old file to the new one. */ | |
266 | ||
3f8a3241 | 267 | copy_file (old, new, size) |
dcfdbac7 JB |
268 | int new, old; |
269 | int size; | |
270 | { | |
271 | int len; | |
b8a0abf2 | 272 | int buffer[8192]; /* word aligned will be faster */ |
dcfdbac7 JB |
273 | |
274 | for (; size > 0; size -= len) | |
275 | { | |
3f8a3241 RS |
276 | len = min (size, sizeof (buffer)); |
277 | if (read (old, buffer, len) != len) | |
278 | { perror ("Read failure on a.out file"); exit (1); } | |
279 | if (write (new, buffer, len) != len) | |
280 | { perror ("Write failure in a.out file"); exit (1); } | |
dcfdbac7 JB |
281 | } |
282 | } | |
283 | ||
284 | /* Copy the rest of the file, up to EOF. */ | |
285 | ||
3f8a3241 | 286 | copy_rest (old, new) |
dcfdbac7 JB |
287 | int new, old; |
288 | { | |
289 | int buffer[4096]; | |
290 | int len; | |
291 | ||
292 | /* Copy bytes until end of file or error */ | |
3f8a3241 RS |
293 | while ((len = read (old, buffer, sizeof (buffer))) > 0) |
294 | if (write (new, buffer, len) != len) break; | |
dcfdbac7 JB |
295 | |
296 | if (len != 0) | |
3f8a3241 | 297 | { perror ("Unable to copy the rest of the file"); exit (1); } |
dcfdbac7 JB |
298 | } |
299 | ||
300 | #ifdef DEBUG | |
3f8a3241 | 301 | display_header (hdr, auxhdr) |
dcfdbac7 JB |
302 | struct header *hdr; |
303 | struct som_exec_auxhdr *auxhdr; | |
304 | { | |
305 | /* Display the header information (debug) */ | |
3f8a3241 RS |
306 | printf ("\n\nFILE HEADER\n"); |
307 | printf ("magic number %d \n", hdr->a_magic); | |
308 | printf ("text loc %.8x size %d \n", auxhdr->exec_tmem, auxhdr->exec_tsize); | |
309 | printf ("data loc %.8x size %d \n", auxhdr->exec_dmem, auxhdr->exec_dsize); | |
310 | printf ("entry %x \n", auxhdr->exec_entry); | |
311 | printf ("Bss segment size %u\n", auxhdr->exec_bsize); | |
312 | printf ("\n"); | |
313 | printf ("data file loc %d size %d\n", | |
314 | auxhdr->exec_dfile, auxhdr->exec_dsize); | |
315 | printf ("som_length %d\n", hdr->som_length); | |
316 | printf ("unloadable sploc %d size %d\n", | |
317 | hdr->unloadable_sp_location, hdr->unloadable_sp_size); | |
dcfdbac7 JB |
318 | } |
319 | #endif /* DEBUG */ |