Commit | Line | Data |
---|---|---|
89117df0 GM |
1 | /* Unexec for HP 9000 Series 800 machines. |
2 | ||
3 | This file is in the public domain. | |
4 | ||
5 | Author: John V. Morris | |
6 | ||
7 | This file was written by John V. Morris at Hewlett Packard. | |
8 | Both the author and Hewlett Packard Co. have disclaimed the | |
9 | copyright on this file, and it is therefore in the public domain. | |
10 | (Search for "hp9k800" in copyright.list.) | |
11 | */ | |
12 | ||
13 | /* | |
14 | Bob Desinger <hpsemc!bd@hplabs.hp.com> | |
15 | ||
16 | Note that the GNU project considers support for HP operation a | |
17 | peripheral activity which should not be allowed to divert effort | |
18 | from development of the GNU system. Changes in this code will be | |
19 | installed when users send them in, but aside from that we don't | |
20 | plan to think about it, or about whether other Emacs maintenance | |
21 | might break it. | |
22 | ||
23 | ||
24 | Unexec creates a copy of the old a.out file, and replaces the old data | |
25 | area with the current data area. When the new file is executed, the | |
26 | process will see the same data structures and data values that the | |
27 | original process had when unexec was called. | |
28 | ||
29 | Unlike other versions of unexec, this one copies symbol table and | |
30 | debug information to the new a.out file. Thus, the new a.out file | |
31 | may be debugged with symbolic debuggers. | |
32 | ||
33 | If you fix any bugs in this, I'd like to incorporate your fixes. | |
34 | Send them to uunet!hpda!hpsemc!jmorris or jmorris%hpsemc@hplabs.HP.COM. | |
35 | ||
36 | CAVEATS: | |
37 | This routine saves the current value of all static and external | |
38 | variables. This means that any data structure that needs to be | |
39 | initialized must be explicitly reset. Variables will not have their | |
40 | expected default values. | |
41 | ||
42 | Unfortunately, the HP-UX signal handler has internal initialization | |
43 | flags which are not explicitly reset. Thus, for signals to work in | |
44 | conjunction with this routine, the following code must executed when | |
45 | the new process starts up. | |
46 | ||
47 | void _sigreturn (); | |
48 | ... | |
49 | sigsetreturn (_sigreturn); | |
50 | */ | |
51 | \f | |
89117df0 | 52 | #include <config.h> |
ce701a33 | 53 | #include "unexec.h" |
406af475 | 54 | #include "lisp.h" |
ce701a33 | 55 | |
89117df0 GM |
56 | #include <stdio.h> |
57 | #include <fcntl.h> | |
58 | #include <errno.h> | |
89117df0 | 59 | #include <a.out.h> |
89117df0 | 60 | #include <dl.h> |
89117df0 GM |
61 | |
62 | /* brk value to restore, stored as a global. | |
63 | This is really used only if we used shared libraries. */ | |
64 | static long brk_on_dump = 0; | |
65 | ||
66 | /* Called from main, if we use shared libraries. */ | |
67 | int | |
1dae0f0a | 68 | run_time_remap (char *ignored) |
89117df0 GM |
69 | { |
70 | brk ((char *) brk_on_dump); | |
71 | } | |
72 | ||
73 | #undef roundup | |
74 | #define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1)) /* n is power of 2 */ | |
75 | #define min(x,y) (((x) < (y)) ? (x) : (y)) | |
76 | ||
89117df0 GM |
77 | /* Save current data space in the file, update header. */ |
78 | ||
1dae0f0a AS |
79 | static void |
80 | save_data_space (int file, struct header *hdr, struct som_exec_auxhdr *auxhdr, | |
81 | int size) | |
89117df0 GM |
82 | { |
83 | /* Write the entire data space out to the file */ | |
84 | if (write (file, auxhdr->exec_dmem, size) != size) | |
85 | { perror ("Can't save new data space"); exit (1); } | |
86 | ||
87 | /* Update the header to reflect the new data size */ | |
88 | auxhdr->exec_dsize = size; | |
89 | auxhdr->exec_bsize = 0; | |
90 | } | |
91 | ||
92 | /* Update the values of file pointers when something is inserted. */ | |
93 | ||
1dae0f0a AS |
94 | static void |
95 | update_file_ptrs (int file, struct header *hdr, struct som_exec_auxhdr *auxhdr, | |
96 | unsigned int location, int offset) | |
89117df0 GM |
97 | { |
98 | struct subspace_dictionary_record subspace; | |
99 | int i; | |
100 | ||
101 | /* Increase the overall size of the module */ | |
102 | hdr->som_length += offset; | |
103 | ||
104 | /* Update the various file pointers in the header */ | |
105 | #define update(ptr) if (ptr > location) ptr = ptr + offset | |
106 | update (hdr->aux_header_location); | |
107 | update (hdr->space_strings_location); | |
108 | update (hdr->init_array_location); | |
109 | update (hdr->compiler_location); | |
110 | update (hdr->symbol_location); | |
111 | update (hdr->fixup_request_location); | |
112 | update (hdr->symbol_strings_location); | |
113 | update (hdr->unloadable_sp_location); | |
114 | update (auxhdr->exec_tfile); | |
115 | update (auxhdr->exec_dfile); | |
116 | ||
117 | /* Do for each subspace dictionary entry */ | |
118 | lseek (file, hdr->subspace_location, 0); | |
119 | for (i = 0; i < hdr->subspace_total; i++) | |
120 | { | |
121 | if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace)) | |
122 | { perror ("Can't read subspace record"); exit (1); } | |
123 | ||
124 | /* If subspace has a file location, update it */ | |
125 | if (subspace.initialization_length > 0 | |
126 | && subspace.file_loc_init_value > location) | |
127 | { | |
128 | subspace.file_loc_init_value += offset; | |
129 | lseek (file, -sizeof (subspace), 1); | |
130 | if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace)) | |
131 | { perror ("Can't update subspace record"); exit (1); } | |
132 | } | |
133 | } | |
134 | ||
135 | /* Do for each initialization pointer record */ | |
136 | /* (I don't think it applies to executable files, only relocatables) */ | |
137 | #undef update | |
138 | } | |
139 | ||
140 | /* Read in the header records from an a.out file. */ | |
141 | ||
1dae0f0a AS |
142 | static void |
143 | read_header (int file, struct header *hdr, struct som_exec_auxhdr *auxhdr) | |
89117df0 GM |
144 | { |
145 | ||
146 | /* Read the header in */ | |
147 | lseek (file, 0, 0); | |
148 | if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
149 | { perror ("Couldn't read header from a.out file"); exit (1); } | |
150 | ||
151 | if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC | |
152 | && hdr->a_magic != DEMAND_MAGIC) | |
153 | { | |
5af1f9fe | 154 | fprintf (stderr, "a.out file doesn't have valid magic number\n"); |
89117df0 GM |
155 | exit (1); |
156 | } | |
157 | ||
158 | lseek (file, hdr->aux_header_location, 0); | |
159 | if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
160 | { | |
161 | perror ("Couldn't read auxiliary header from a.out file"); | |
162 | exit (1); | |
163 | } | |
164 | } | |
165 | ||
166 | /* Write out the header records into an a.out file. */ | |
167 | ||
1dae0f0a AS |
168 | static void |
169 | write_header (int file, struct header *hdr, struct som_exec_auxhdr *auxhdr) | |
89117df0 GM |
170 | { |
171 | /* Update the checksum */ | |
172 | hdr->checksum = calculate_checksum (hdr); | |
173 | ||
174 | /* Write the header back into the a.out file */ | |
175 | lseek (file, 0, 0); | |
176 | if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr)) | |
177 | { perror ("Couldn't write header to a.out file"); exit (1); } | |
178 | lseek (file, hdr->aux_header_location, 0); | |
179 | if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr)) | |
180 | { perror ("Couldn't write auxiliary header to a.out file"); exit (1); } | |
181 | } | |
182 | ||
183 | /* Calculate the checksum of a SOM header record. */ | |
184 | ||
1dae0f0a AS |
185 | static int |
186 | calculate_checksum (struct header *hdr) | |
89117df0 GM |
187 | { |
188 | int checksum, i, *ptr; | |
189 | ||
190 | checksum = 0; ptr = (int *) hdr; | |
191 | ||
192 | for (i = 0; i < sizeof (*hdr) / sizeof (int) - 1; i++) | |
193 | checksum ^= ptr[i]; | |
194 | ||
195 | return (checksum); | |
196 | } | |
197 | ||
198 | /* Copy size bytes from the old file to the new one. */ | |
199 | ||
1dae0f0a AS |
200 | static void |
201 | copy_file (int old, int new, int size) | |
89117df0 GM |
202 | { |
203 | int len; | |
204 | int buffer[8192]; /* word aligned will be faster */ | |
205 | ||
206 | for (; size > 0; size -= len) | |
207 | { | |
208 | len = min (size, sizeof (buffer)); | |
209 | if (read (old, buffer, len) != len) | |
210 | { perror ("Read failure on a.out file"); exit (1); } | |
211 | if (write (new, buffer, len) != len) | |
212 | { perror ("Write failure in a.out file"); exit (1); } | |
213 | } | |
214 | } | |
215 | ||
216 | /* Copy the rest of the file, up to EOF. */ | |
217 | ||
1dae0f0a AS |
218 | static void |
219 | copy_rest (int old, int new) | |
89117df0 GM |
220 | { |
221 | int buffer[4096]; | |
222 | int len; | |
223 | ||
224 | /* Copy bytes until end of file or error */ | |
225 | while ((len = read (old, buffer, sizeof (buffer))) > 0) | |
226 | if (write (new, buffer, len) != len) break; | |
227 | ||
228 | if (len != 0) | |
229 | { perror ("Unable to copy the rest of the file"); exit (1); } | |
230 | } | |
231 | ||
232 | #ifdef DEBUG | |
1dae0f0a AS |
233 | static void |
234 | display_header (struct header *hdr, struct som_exec_auxhdr *auxhdr) | |
89117df0 GM |
235 | { |
236 | /* Display the header information (debug) */ | |
237 | printf ("\n\nFILE HEADER\n"); | |
238 | printf ("magic number %d \n", hdr->a_magic); | |
239 | printf ("text loc %.8x size %d \n", auxhdr->exec_tmem, auxhdr->exec_tsize); | |
240 | printf ("data loc %.8x size %d \n", auxhdr->exec_dmem, auxhdr->exec_dsize); | |
241 | printf ("entry %x \n", auxhdr->exec_entry); | |
242 | printf ("Bss segment size %u\n", auxhdr->exec_bsize); | |
243 | printf ("\n"); | |
244 | printf ("data file loc %d size %d\n", | |
245 | auxhdr->exec_dfile, auxhdr->exec_dsize); | |
246 | printf ("som_length %d\n", hdr->som_length); | |
247 | printf ("unloadable sploc %d size %d\n", | |
248 | hdr->unloadable_sp_location, hdr->unloadable_sp_size); | |
249 | } | |
250 | #endif /* DEBUG */ | |
1dae0f0a AS |
251 | |
252 | ||
253 | /* Create a new a.out file, same as old but with current data space */ | |
254 | void | |
255 | unexec (const char *new_name, /* name of the new a.out file to be created */ | |
256 | const char *old_name) /* name of the old a.out file */ | |
257 | { | |
258 | int old, new; | |
259 | int old_size, new_size; | |
260 | struct header hdr; | |
261 | struct som_exec_auxhdr auxhdr; | |
262 | long i; | |
263 | ||
264 | /* For the greatest flexibility, should create a temporary file in | |
265 | the same directory as the new file. When everything is complete, | |
266 | rename the temp file to the new name. | |
267 | This way, a program could update its own a.out file even while | |
268 | it is still executing. If problems occur, everything is still | |
269 | intact. NOT implemented. */ | |
270 | ||
271 | /* Open the input and output a.out files */ | |
406af475 | 272 | old = emacs_open (old_name, O_RDONLY, 0); |
1dae0f0a AS |
273 | if (old < 0) |
274 | { perror (old_name); exit (1); } | |
406af475 | 275 | new = emacs_open (new_name, O_CREAT | O_RDWR | O_TRUNC, 0777); |
1dae0f0a AS |
276 | if (new < 0) |
277 | { perror (new_name); exit (1); } | |
278 | ||
279 | /* Read the old headers */ | |
280 | read_header (old, &hdr, &auxhdr); | |
281 | ||
282 | brk_on_dump = (long) sbrk (0); | |
283 | ||
284 | /* Decide how large the new and old data areas are */ | |
285 | old_size = auxhdr.exec_dsize; | |
286 | /* I suspect these two statements are separate | |
287 | to avoid a compiler bug in hpux version 8. */ | |
288 | i = (long) sbrk (0); | |
289 | new_size = i - auxhdr.exec_dmem; | |
290 | ||
291 | /* Copy the old file to the new, up to the data space */ | |
292 | lseek (old, 0, 0); | |
293 | copy_file (old, new, auxhdr.exec_dfile); | |
294 | ||
295 | /* Skip the old data segment and write a new one */ | |
296 | lseek (old, old_size, 1); | |
297 | save_data_space (new, &hdr, &auxhdr, new_size); | |
298 | ||
299 | /* Copy the rest of the file */ | |
300 | copy_rest (old, new); | |
301 | ||
302 | /* Update file pointers since we probably changed size of data area */ | |
303 | update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size); | |
304 | ||
305 | /* Save the modified header */ | |
306 | write_header (new, &hdr, &auxhdr); | |
307 | ||
308 | /* Close the binary file */ | |
bacba3c2 PE |
309 | emacs_close (old); |
310 | emacs_close (new); | |
1dae0f0a | 311 | } |