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7838db54 ML |
1 | /* Copyright (c) 1982 Regents of the University of California */ |
2 | ||
33ece7d5 | 3 | static char sccsid[] = "@(#)ptrace.c 1.2 %G%"; |
7838db54 ML |
4 | |
5 | /* | |
6 | * routines for tracing the execution of a process | |
7 | * | |
8 | * The system call "ptrace" does all the work, these | |
9 | * routines just try to interface easily to it. | |
10 | */ | |
11 | ||
12 | #include "defs.h" | |
13 | #include <signal.h> | |
14 | #include <sys/param.h> | |
15 | #include <sys/reg.h> | |
16 | #include "process.h" | |
17 | #include "object.h" | |
18 | #include "process.rep" | |
19 | ||
20 | # if (isvaxpx) | |
21 | # include "pxinfo.h" | |
22 | # endif | |
23 | ||
24 | /* | |
25 | * This magic macro enables us to look at the process' registers | |
26 | * in its user structure. Very gross. | |
27 | */ | |
28 | ||
29 | #define regloc(reg) (ctob(UPAGES) + ( sizeof(int) * (reg) )) | |
30 | ||
31 | #define WMASK (~(sizeof(WORD) - 1)) | |
32 | #define cachehash(addr) ((unsigned) ((addr >> 2) % CSIZE)) | |
33 | ||
34 | #define FIRSTSIG SIGINT | |
35 | #define LASTSIG SIGQUIT | |
36 | #define ischild(pid) ((pid) == 0) | |
37 | #define traceme() ptrace(0, 0, 0, 0) | |
38 | #define setrep(n) (1 << ((n)-1)) | |
39 | #define istraced(p) (p->sigset&setrep(p->signo)) | |
40 | ||
41 | /* | |
42 | * ptrace options (specified in first argument) | |
43 | */ | |
44 | ||
45 | #define UREAD 3 /* read from process's user structure */ | |
46 | #define UWRITE 6 /* write to process's user structure */ | |
47 | #define IREAD 1 /* read from process's instruction space */ | |
48 | #define IWRITE 4 /* write to process's instruction space */ | |
49 | #define DREAD 2 /* read from process's data space */ | |
50 | #define DWRITE 5 /* write to process's data space */ | |
51 | #define CONT 7 /* continue stopped process */ | |
52 | #define SSTEP 9 /* continue for approximately one instruction */ | |
53 | #define PKILL 8 /* terminate the process */ | |
54 | ||
55 | /* | |
56 | * Start up a new process by forking and exec-ing the | |
57 | * given argument list, returning when the process is loaded | |
58 | * and ready to execute. The PROCESS information (pointed to | |
59 | * by the first argument) is appropriately filled. | |
60 | * | |
61 | * If the given PROCESS structure is associated with an already running | |
62 | * process, we terminate it. | |
63 | */ | |
64 | ||
65 | /* VARARGS2 */ | |
33ece7d5 | 66 | pstart(p, cmd, argv, infile, outfile) |
7838db54 | 67 | PROCESS *p; |
33ece7d5 | 68 | char *cmd; |
7838db54 ML |
69 | char **argv; |
70 | char *infile; | |
71 | char *outfile; | |
72 | { | |
73 | int status; | |
74 | FILE *in, *out; | |
75 | ||
76 | if (p->pid != 0) { /* child already running? */ | |
77 | ptrace(PKILL, p->pid, 0, 0); /* ... kill it! */ | |
78 | } | |
79 | psigtrace(p, SIGTRAP, TRUE); | |
80 | if ((p->pid = fork()) == -1) { | |
81 | panic("can't fork"); | |
82 | } | |
83 | if (ischild(p->pid)) { | |
84 | traceme(); | |
85 | if (infile != NIL) { | |
86 | if ((in = fopen(infile, "r")) == NIL) { | |
87 | printf("can't read %s\n", infile); | |
88 | exit(1); | |
89 | } | |
90 | fswap(0, fileno(in)); | |
91 | } | |
92 | if (outfile != NIL) { | |
93 | if ((out = fopen(outfile, "w")) == NIL) { | |
94 | printf("can't write %s\n", outfile); | |
95 | exit(1); | |
96 | } | |
97 | fswap(1, fileno(out)); | |
98 | } | |
33ece7d5 | 99 | execvp(cmd, argv); |
7838db54 ML |
100 | panic("can't exec %s", argv[0]); |
101 | } | |
102 | pwait(p->pid, &status); | |
103 | getinfo(p, status); | |
7838db54 ML |
104 | } |
105 | ||
106 | /* | |
107 | * Continue a stopped process. The argument points to a PROCESS structure. | |
108 | * Before the process is restarted it's user area is modified according to | |
109 | * the values in the structure. When this routine finishes, | |
110 | * the structure has the new values from the process's user area. | |
111 | * | |
112 | * Pcont terminates when the process stops with a signal pending that | |
113 | * is being traced (via psigtrace), or when the process terminates. | |
114 | */ | |
115 | ||
116 | pcont(p) | |
117 | PROCESS *p; | |
118 | { | |
119 | int status; | |
120 | ||
121 | if (p->pid == 0) { | |
122 | error("program not active"); | |
123 | } | |
124 | do { | |
125 | setinfo(p); | |
126 | sigs_off(); | |
127 | if (ptrace(CONT, p->pid, p->pc, p->signo) < 0) { | |
128 | panic("can't continue process"); | |
129 | } | |
130 | pwait(p->pid, &status); | |
131 | sigs_on(); | |
132 | getinfo(p, status); | |
133 | } while (p->status == STOPPED && !istraced(p)); | |
134 | } | |
135 | ||
136 | /* | |
137 | * single step as best ptrace can | |
138 | */ | |
139 | ||
140 | pstep(p) | |
141 | PROCESS *p; | |
142 | { | |
143 | int status; | |
144 | ||
145 | setinfo(p); | |
146 | sigs_off(); | |
147 | ptrace(SSTEP, p->pid, p->pc, p->signo); | |
148 | pwait(p->pid, &status); | |
149 | sigs_on(); | |
150 | getinfo(p, status); | |
151 | } | |
152 | ||
153 | /* | |
154 | * Return from execution when the given signal is pending. | |
155 | */ | |
156 | ||
157 | psigtrace(p, sig, sw) | |
158 | PROCESS *p; | |
159 | int sig; | |
160 | int sw; | |
161 | { | |
162 | if (sw) { | |
163 | p->sigset |= setrep(sig); | |
164 | } else { | |
165 | p->sigset &= ~setrep(sig); | |
166 | } | |
167 | } | |
168 | ||
169 | /* | |
170 | * Don't catch any signals. | |
171 | * Particularly useful when letting a process finish uninhibited (i.e. px). | |
172 | */ | |
173 | ||
174 | unsetsigtraces(p) | |
175 | PROCESS *p; | |
176 | { | |
177 | p->sigset = 0; | |
178 | } | |
179 | ||
180 | /* | |
181 | * turn off attention to signals not being caught | |
182 | */ | |
183 | ||
184 | typedef int INTFUNC(); | |
185 | ||
186 | LOCAL INTFUNC *sigfunc[NSIG]; | |
187 | ||
188 | LOCAL sigs_off() | |
189 | { | |
190 | register int i; | |
191 | ||
192 | for (i = FIRSTSIG; i < LASTSIG; i++) { | |
193 | if (i != SIGKILL) { | |
194 | sigfunc[i] = signal(i, SIG_IGN); | |
195 | } | |
196 | } | |
197 | } | |
198 | ||
199 | /* | |
200 | * turn back on attention to signals | |
201 | */ | |
202 | ||
203 | LOCAL sigs_on() | |
204 | { | |
205 | register int i; | |
206 | ||
207 | for (i = FIRSTSIG; i < LASTSIG; i++) { | |
208 | if (i != SIGKILL) { | |
209 | signal(i, sigfunc[i]); | |
210 | } | |
211 | } | |
212 | } | |
213 | ||
214 | /* | |
215 | * get PROCESS information from process's user area | |
216 | */ | |
217 | ||
218 | LOCAL int rloc[] ={ | |
219 | R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, | |
220 | }; | |
221 | ||
222 | LOCAL getinfo(p, status) | |
223 | register PROCESS *p; | |
224 | register int status; | |
225 | { | |
226 | register int i; | |
227 | ||
228 | p->signo = (status&0177); | |
229 | p->exitval = ((status >> 8)&0377); | |
230 | if (p->signo == STOPPED) { | |
231 | p->status = p->signo; | |
232 | p->signo = p->exitval; | |
233 | p->exitval = 0; | |
234 | } else { | |
235 | p->status = FINISHED; | |
236 | return; | |
237 | } | |
238 | for (i = 0; i < NREG; i++) { | |
239 | p->reg[i] = ptrace(UREAD, p->pid, regloc(rloc[i]), 0); | |
240 | p->oreg[i] = p->reg[i]; | |
241 | } | |
242 | p->fp = p->ofp = ptrace(UREAD, p->pid, regloc(FP), 0); | |
243 | p->ap = p->oap = ptrace(UREAD, p->pid, regloc(AP), 0); | |
244 | p->sp = p->osp = ptrace(UREAD, p->pid, regloc(SP), 0); | |
245 | p->pc = p->opc = ptrace(UREAD, p->pid, regloc(PC), 0); | |
246 | } | |
247 | ||
248 | /* | |
249 | * set process's user area information from given PROCESS structure | |
250 | */ | |
251 | ||
252 | LOCAL setinfo(p) | |
253 | register PROCESS *p; | |
254 | { | |
255 | register int i; | |
256 | register int r; | |
257 | ||
258 | if (istraced(p)) { | |
259 | p->signo = 0; | |
260 | } | |
261 | for (i = 0; i < NREG; i++) { | |
262 | if ((r = p->reg[i]) != p->oreg[i]) { | |
263 | ptrace(UWRITE, p->pid, regloc(rloc[i]), r); | |
264 | } | |
265 | } | |
266 | if ((r = p->fp) != p->ofp) { | |
267 | ptrace(UWRITE, p->pid, regloc(FP), r); | |
268 | } | |
269 | if ((r = p->sp) != p->osp) { | |
270 | ptrace(UWRITE, p->pid, regloc(SP), r); | |
271 | } | |
272 | if ((r = p->ap) != p->oap) { | |
273 | ptrace(UWRITE, p->pid, regloc(AP), r); | |
274 | } | |
275 | if ((r = p->pc) != p->opc) { | |
276 | ptrace(UWRITE, p->pid, regloc(PC), r); | |
277 | } | |
278 | } | |
279 | ||
280 | /* | |
281 | * Structure for reading and writing by words, but dealing with bytes. | |
282 | */ | |
283 | ||
284 | typedef union { | |
285 | WORD pword; | |
286 | BYTE pbyte[sizeof(WORD)]; | |
287 | } PWORD; | |
288 | ||
289 | /* | |
290 | * Read (write) from (to) the process' address space. | |
291 | * We must deal with ptrace's inability to look anywhere other | |
292 | * than at a word boundary. | |
293 | */ | |
294 | ||
295 | LOCAL WORD fetch(); | |
296 | LOCAL store(); | |
297 | ||
298 | pio(p, op, seg, buff, addr, nbytes) | |
299 | PROCESS *p; | |
300 | PIO_OP op; | |
301 | PIO_SEG seg; | |
302 | char *buff; | |
303 | ADDRESS addr; | |
304 | int nbytes; | |
305 | { | |
306 | register int i; | |
307 | register ADDRESS newaddr; | |
308 | register char *cp; | |
309 | char *bufend; | |
310 | PWORD w; | |
311 | ADDRESS wordaddr; | |
312 | int byteoff; | |
313 | ||
314 | if (p->status != STOPPED) { | |
315 | error("program is not active"); | |
316 | } | |
317 | cp = buff; | |
318 | newaddr = addr; | |
319 | wordaddr = (newaddr&WMASK); | |
320 | if (wordaddr != newaddr) { | |
321 | w.pword = fetch(p, seg, wordaddr); | |
322 | for (i = newaddr - wordaddr; i<sizeof(WORD) && nbytes>0; i++) { | |
323 | if (op == PREAD) { | |
324 | *cp++ = w.pbyte[i]; | |
325 | } else { | |
326 | w.pbyte[i] = *cp++; | |
327 | } | |
328 | nbytes--; | |
329 | } | |
330 | if (op == PWRITE) { | |
331 | store(p, seg, wordaddr, w.pword); | |
332 | } | |
333 | newaddr = wordaddr + sizeof(WORD); | |
334 | } | |
335 | byteoff = (nbytes&(~WMASK)); | |
336 | nbytes -= byteoff; | |
337 | bufend = cp + nbytes; | |
338 | while (cp < bufend) { | |
339 | if (op == PREAD) { | |
340 | *((WORD *) cp) = fetch(p, seg, newaddr); | |
341 | } else { | |
342 | store(p, seg, newaddr, *((WORD *) cp)); | |
343 | } | |
344 | cp += sizeof(WORD); | |
345 | newaddr += sizeof(WORD); | |
346 | } | |
347 | if (byteoff > 0) { | |
348 | w.pword = fetch(p, seg, newaddr); | |
349 | for (i = 0; i < byteoff; i++) { | |
350 | if (op == PREAD) { | |
351 | *cp++ = w.pbyte[i]; | |
352 | } else { | |
353 | w.pbyte[i] = *cp++; | |
354 | } | |
355 | } | |
356 | if (op == PWRITE) { | |
357 | store(p, seg, newaddr, w.pword); | |
358 | } | |
359 | } | |
360 | } | |
361 | ||
362 | /* | |
363 | * Get a word from a process at the given address. | |
364 | * The address is assumed to be on a word boundary. | |
365 | * | |
366 | * We use a simple cache scheme to avoid redundant references to | |
367 | * the instruction space (which is assumed to be pure). In the | |
368 | * case of px, the "instruction" space lies between ENDOFF and | |
369 | * ENDOFF + objsize. | |
370 | * | |
371 | * It is necessary to use a write-through scheme so that | |
372 | * breakpoints right next to each other don't interfere. | |
373 | */ | |
374 | ||
375 | LOCAL WORD fetch(p, seg, addr) | |
376 | PROCESS *p; | |
377 | PIO_SEG seg; | |
378 | register int addr; | |
379 | { | |
380 | register CACHEWORD *wp; | |
381 | register WORD w; | |
382 | ||
383 | switch (seg) { | |
384 | case TEXTSEG: | |
385 | # if (isvaxpx) | |
386 | panic("tried to fetch from px i-space"); | |
387 | /* NOTREACHED */ | |
388 | # else | |
389 | wp = &p->word[cachehash(addr)]; | |
390 | if (addr == 0 || wp->addr != addr) { | |
391 | w = ptrace(IREAD, p->pid, addr, 0); | |
392 | wp->addr = addr; | |
393 | wp->val = w; | |
394 | } else { | |
395 | w = wp->val; | |
396 | } | |
397 | break; | |
398 | # endif | |
399 | ||
400 | case DATASEG: | |
401 | # if (isvaxpx) | |
402 | if (addr >= ENDOFF && addr < ENDOFF + objsize) { | |
403 | wp = &p->word[cachehash(addr)]; | |
404 | if (addr == 0 || wp->addr != addr) { | |
405 | w = ptrace(DREAD, p->pid, addr, 0); | |
406 | wp->addr = addr; | |
407 | wp->val = w; | |
408 | } else { | |
409 | w = wp->val; | |
410 | } | |
411 | } else { | |
412 | w = ptrace(DREAD, p->pid, addr, 0); | |
413 | } | |
414 | # else | |
415 | w = ptrace(DREAD, p->pid, addr, 0); | |
416 | # endif | |
417 | break; | |
418 | ||
419 | default: | |
420 | panic("fetch: bad seg %d", seg); | |
421 | /* NOTREACHED */ | |
422 | } | |
423 | return(w); | |
424 | } | |
425 | ||
426 | /* | |
427 | * Put a word into the process' address space at the given address. | |
428 | * The address is assumed to be on a word boundary. | |
429 | */ | |
430 | ||
431 | LOCAL store(p, seg, addr, data) | |
432 | PROCESS *p; | |
433 | PIO_SEG seg; | |
434 | int addr; | |
435 | WORD data; | |
436 | { | |
437 | register CACHEWORD *wp; | |
438 | ||
439 | switch (seg) { | |
440 | case TEXTSEG: | |
441 | wp = &p->word[cachehash(addr)]; | |
442 | wp->addr = addr; | |
443 | wp->val = data; | |
444 | ptrace(IWRITE, p->pid, addr, data); | |
445 | break; | |
446 | ||
447 | case DATASEG: | |
448 | # if (isvaxpx) | |
449 | if (addr >= ENDOFF && addr < ENDOFF + objsize) { | |
450 | wp = &p->word[cachehash(addr)]; | |
451 | wp->addr = addr; | |
452 | wp->val = data; | |
453 | } | |
454 | # endif | |
455 | ptrace(DWRITE, p->pid, addr, data); | |
456 | break; | |
457 | ||
458 | default: | |
459 | panic("store: bad seg %d", seg); | |
460 | /*NOTREACHED*/ | |
461 | } | |
462 | } | |
463 | ||
464 | /* | |
465 | * Swap file numbers so as to redirect standard input and output. | |
466 | */ | |
467 | ||
468 | LOCAL fswap(oldfd, newfd) | |
469 | int oldfd; | |
470 | int newfd; | |
471 | { | |
472 | if (oldfd != newfd) { | |
473 | close(oldfd); | |
474 | dup(newfd); | |
475 | close(newfd); | |
476 | } | |
477 | } |