| 1 | /* |
| 2 | * Copyright (c) 1980 Regents of the University of California. |
| 3 | * All rights reserved. The Berkeley software License Agreement |
| 4 | * specifies the terms and conditions for redistribution. |
| 5 | */ |
| 6 | |
| 7 | #ifndef lint |
| 8 | static char sccsid[] = "@(#)ptrace.c 5.1 (Berkeley) %G%"; |
| 9 | #endif not lint |
| 10 | |
| 11 | /* |
| 12 | * routines for tracing the execution of a process |
| 13 | * |
| 14 | * The system call "ptrace" does all the work, these |
| 15 | * routines just try to interface easily to it. |
| 16 | */ |
| 17 | |
| 18 | #include "defs.h" |
| 19 | #include <signal.h> |
| 20 | #include <sys/param.h> |
| 21 | #include <machine/reg.h> |
| 22 | #include "process.h" |
| 23 | #include "object.h" |
| 24 | #include "process.rep" |
| 25 | |
| 26 | # if (isvaxpx) |
| 27 | # include "pxinfo.h" |
| 28 | # endif |
| 29 | |
| 30 | #ifndef vax |
| 31 | # define U_PAGE 0x2400 |
| 32 | # define U_AR0 (14*sizeof(int)) |
| 33 | LOCAL int ar0val = -1; |
| 34 | #endif |
| 35 | |
| 36 | /* |
| 37 | * This magic macro enables us to look at the process' registers |
| 38 | * in its user structure. Very gross. |
| 39 | */ |
| 40 | |
| 41 | #ifdef vax |
| 42 | # define regloc(reg) (ctob(UPAGES) + ( sizeof(int) * (reg) )) |
| 43 | #else |
| 44 | # define regloc(reg) (ar0val + ( sizeof(int) * (reg) )) |
| 45 | #endif |
| 46 | |
| 47 | #define WMASK (~(sizeof(WORD) - 1)) |
| 48 | #define cachehash(addr) ((unsigned) ((addr >> 2) % CSIZE)) |
| 49 | |
| 50 | #define FIRSTSIG SIGINT |
| 51 | #define LASTSIG SIGQUIT |
| 52 | #define ischild(pid) ((pid) == 0) |
| 53 | #define traceme() ptrace(0, 0, 0, 0) |
| 54 | #define setrep(n) (1 << ((n)-1)) |
| 55 | #define istraced(p) (p->sigset&setrep(p->signo)) |
| 56 | |
| 57 | /* |
| 58 | * ptrace options (specified in first argument) |
| 59 | */ |
| 60 | |
| 61 | #define UREAD 3 /* read from process's user structure */ |
| 62 | #define UWRITE 6 /* write to process's user structure */ |
| 63 | #define IREAD 1 /* read from process's instruction space */ |
| 64 | #define IWRITE 4 /* write to process's instruction space */ |
| 65 | #define DREAD 2 /* read from process's data space */ |
| 66 | #define DWRITE 5 /* write to process's data space */ |
| 67 | #define CONT 7 /* continue stopped process */ |
| 68 | #define SSTEP 9 /* continue for approximately one instruction */ |
| 69 | #define PKILL 8 /* terminate the process */ |
| 70 | |
| 71 | /* |
| 72 | * Start up a new process by forking and exec-ing the |
| 73 | * given argument list, returning when the process is loaded |
| 74 | * and ready to execute. The PROCESS information (pointed to |
| 75 | * by the first argument) is appropriately filled. |
| 76 | * |
| 77 | * If the given PROCESS structure is associated with an already running |
| 78 | * process, we terminate it. |
| 79 | */ |
| 80 | |
| 81 | /* VARARGS2 */ |
| 82 | pstart(p, cmd, argv, infile, outfile) |
| 83 | PROCESS *p; |
| 84 | char *cmd; |
| 85 | char **argv; |
| 86 | char *infile; |
| 87 | char *outfile; |
| 88 | { |
| 89 | int status; |
| 90 | FILE *in, *out; |
| 91 | |
| 92 | if (p->pid != 0) { /* child already running? */ |
| 93 | ptrace(PKILL, p->pid, 0, 0); /* ... kill it! */ |
| 94 | } |
| 95 | psigtrace(p, SIGTRAP, TRUE); |
| 96 | if ((p->pid = fork()) == -1) { |
| 97 | panic("can't fork"); |
| 98 | } |
| 99 | if (ischild(p->pid)) { |
| 100 | traceme(); |
| 101 | if (infile != NIL) { |
| 102 | if ((in = fopen(infile, "r")) == NIL) { |
| 103 | printf("can't read %s\n", infile); |
| 104 | exit(1); |
| 105 | } |
| 106 | fswap(0, fileno(in)); |
| 107 | } |
| 108 | if (outfile != NIL) { |
| 109 | if ((out = fopen(outfile, "w")) == NIL) { |
| 110 | printf("can't write %s\n", outfile); |
| 111 | exit(1); |
| 112 | } |
| 113 | fswap(1, fileno(out)); |
| 114 | } |
| 115 | execvp(cmd, argv); |
| 116 | panic("can't exec %s", argv[0]); |
| 117 | } |
| 118 | pwait(p->pid, &status); |
| 119 | getinfo(p, status); |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Continue a stopped process. The argument points to a PROCESS structure. |
| 124 | * Before the process is restarted it's user area is modified according to |
| 125 | * the values in the structure. When this routine finishes, |
| 126 | * the structure has the new values from the process's user area. |
| 127 | * |
| 128 | * Pcont terminates when the process stops with a signal pending that |
| 129 | * is being traced (via psigtrace), or when the process terminates. |
| 130 | */ |
| 131 | |
| 132 | pcont(p) |
| 133 | PROCESS *p; |
| 134 | { |
| 135 | int status; |
| 136 | |
| 137 | if (p->pid == 0) { |
| 138 | error("program not active"); |
| 139 | } |
| 140 | do { |
| 141 | setinfo(p); |
| 142 | sigs_off(); |
| 143 | if (ptrace(CONT, p->pid, p->pc, p->signo) < 0) { |
| 144 | panic("can't continue process"); |
| 145 | } |
| 146 | pwait(p->pid, &status); |
| 147 | sigs_on(); |
| 148 | getinfo(p, status); |
| 149 | } while (p->status == STOPPED && !istraced(p)); |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * single step as best ptrace can |
| 154 | */ |
| 155 | |
| 156 | pstep(p) |
| 157 | PROCESS *p; |
| 158 | { |
| 159 | int status; |
| 160 | |
| 161 | setinfo(p); |
| 162 | sigs_off(); |
| 163 | ptrace(SSTEP, p->pid, p->pc, p->signo); |
| 164 | pwait(p->pid, &status); |
| 165 | sigs_on(); |
| 166 | getinfo(p, status); |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Return from execution when the given signal is pending. |
| 171 | */ |
| 172 | |
| 173 | psigtrace(p, sig, sw) |
| 174 | PROCESS *p; |
| 175 | int sig; |
| 176 | int sw; |
| 177 | { |
| 178 | if (sw) { |
| 179 | p->sigset |= setrep(sig); |
| 180 | } else { |
| 181 | p->sigset &= ~setrep(sig); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * Don't catch any signals. |
| 187 | * Particularly useful when letting a process finish uninhibited (i.e. px). |
| 188 | */ |
| 189 | |
| 190 | unsetsigtraces(p) |
| 191 | PROCESS *p; |
| 192 | { |
| 193 | p->sigset = 0; |
| 194 | } |
| 195 | |
| 196 | /* |
| 197 | * turn off attention to signals not being caught |
| 198 | */ |
| 199 | |
| 200 | typedef int INTFUNC(); |
| 201 | |
| 202 | LOCAL INTFUNC *sigfunc[NSIG]; |
| 203 | |
| 204 | LOCAL sigs_off() |
| 205 | { |
| 206 | register int i; |
| 207 | |
| 208 | for (i = FIRSTSIG; i < LASTSIG; i++) { |
| 209 | if (i != SIGKILL) { |
| 210 | sigfunc[i] = signal(i, SIG_IGN); |
| 211 | } |
| 212 | } |
| 213 | } |
| 214 | |
| 215 | /* |
| 216 | * turn back on attention to signals |
| 217 | */ |
| 218 | |
| 219 | LOCAL sigs_on() |
| 220 | { |
| 221 | register int i; |
| 222 | |
| 223 | for (i = FIRSTSIG; i < LASTSIG; i++) { |
| 224 | if (i != SIGKILL) { |
| 225 | signal(i, sigfunc[i]); |
| 226 | } |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | /* |
| 231 | * get PROCESS information from process's user area |
| 232 | */ |
| 233 | |
| 234 | #if vax |
| 235 | LOCAL int rloc[] ={ |
| 236 | R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, |
| 237 | }; |
| 238 | #else |
| 239 | LOCAL int rloc[] ={ |
| 240 | R0, R1, R2, R3, R4, R5, R6, R7, AR0, AR1, AR2, AR3, AR4, AR5, |
| 241 | }; |
| 242 | #endif |
| 243 | |
| 244 | LOCAL getinfo(p, status) |
| 245 | register PROCESS *p; |
| 246 | register int status; |
| 247 | { |
| 248 | register int i; |
| 249 | |
| 250 | p->signo = (status&0177); |
| 251 | p->exitval = ((status >> 8)&0377); |
| 252 | if (p->signo == STOPPED) { |
| 253 | p->status = p->signo; |
| 254 | p->signo = p->exitval; |
| 255 | p->exitval = 0; |
| 256 | } else { |
| 257 | p->status = FINISHED; |
| 258 | return; |
| 259 | } |
| 260 | #ifndef vax |
| 261 | if (ar0val < 0){ |
| 262 | ar0val = ptrace(UREAD, p->pid, U_AR0, 0); |
| 263 | ar0val -= U_PAGE; |
| 264 | } |
| 265 | #endif |
| 266 | for (i = 0; i < NREG; i++) { |
| 267 | p->reg[i] = ptrace(UREAD, p->pid, regloc(rloc[i]), 0); |
| 268 | p->oreg[i] = p->reg[i]; |
| 269 | } |
| 270 | #ifdef vax |
| 271 | p->fp = p->ofp = ptrace(UREAD, p->pid, regloc(FP), 0); |
| 272 | p->ap = p->oap = ptrace(UREAD, p->pid, regloc(AP), 0); |
| 273 | p->sp = p->osp = ptrace(UREAD, p->pid, regloc(SP), 0); |
| 274 | p->pc = p->opc = ptrace(UREAD, p->pid, regloc(PC), 0); |
| 275 | #else |
| 276 | p->fp = p->ofp = ptrace(UREAD, p->pid, regloc(AR6), 0); |
| 277 | p->ap = p->oap = p->fp; |
| 278 | p->sp = p->osp = ptrace(UREAD, p->pid, regloc(SP), 0); |
| 279 | p->pc = p->opc = ptrace(UREAD, p->pid, regloc(PC), 0); |
| 280 | #endif |
| 281 | } |
| 282 | |
| 283 | /* |
| 284 | * set process's user area information from given PROCESS structure |
| 285 | */ |
| 286 | |
| 287 | LOCAL setinfo(p) |
| 288 | register PROCESS *p; |
| 289 | { |
| 290 | register int i; |
| 291 | register int r; |
| 292 | |
| 293 | if (istraced(p)) { |
| 294 | p->signo = 0; |
| 295 | } |
| 296 | for (i = 0; i < NREG; i++) { |
| 297 | if ((r = p->reg[i]) != p->oreg[i]) { |
| 298 | ptrace(UWRITE, p->pid, regloc(rloc[i]), r); |
| 299 | } |
| 300 | } |
| 301 | #if vax |
| 302 | if ((r = p->fp) != p->ofp) { |
| 303 | ptrace(UWRITE, p->pid, regloc(FP), r); |
| 304 | } |
| 305 | if ((r = p->sp) != p->osp) { |
| 306 | ptrace(UWRITE, p->pid, regloc(SP), r); |
| 307 | } |
| 308 | if ((r = p->ap) != p->oap) { |
| 309 | ptrace(UWRITE, p->pid, regloc(AP), r); |
| 310 | } |
| 311 | #else |
| 312 | if ((r = p->fp) != p->ofp) { |
| 313 | ptrace(UWRITE, p->pid, regloc(AR6), r); |
| 314 | } |
| 315 | if ((r = p->sp) != p->osp) { |
| 316 | ptrace(UWRITE, p->pid, regloc(SP), r); |
| 317 | } |
| 318 | #endif |
| 319 | if ((r = p->pc) != p->opc) { |
| 320 | ptrace(UWRITE, p->pid, regloc(PC), r); |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | /* |
| 325 | * Structure for reading and writing by words, but dealing with bytes. |
| 326 | */ |
| 327 | |
| 328 | typedef union { |
| 329 | WORD pword; |
| 330 | BYTE pbyte[sizeof(WORD)]; |
| 331 | } PWORD; |
| 332 | |
| 333 | /* |
| 334 | * Read (write) from (to) the process' address space. |
| 335 | * We must deal with ptrace's inability to look anywhere other |
| 336 | * than at a word boundary. |
| 337 | */ |
| 338 | |
| 339 | LOCAL WORD fetch(); |
| 340 | LOCAL store(); |
| 341 | |
| 342 | pio(p, op, seg, buff, addr, nbytes) |
| 343 | PROCESS *p; |
| 344 | PIO_OP op; |
| 345 | PIO_SEG seg; |
| 346 | char *buff; |
| 347 | ADDRESS addr; |
| 348 | int nbytes; |
| 349 | { |
| 350 | register int i; |
| 351 | register ADDRESS newaddr; |
| 352 | register char *cp; |
| 353 | char *bufend; |
| 354 | PWORD w; |
| 355 | ADDRESS wordaddr; |
| 356 | int byteoff; |
| 357 | |
| 358 | if (p->status != STOPPED) { |
| 359 | error("program is not active"); |
| 360 | } |
| 361 | cp = buff; |
| 362 | newaddr = addr; |
| 363 | wordaddr = (newaddr&WMASK); |
| 364 | if (wordaddr != newaddr) { |
| 365 | w.pword = fetch(p, seg, wordaddr); |
| 366 | for (i = newaddr - wordaddr; i<sizeof(WORD) && nbytes>0; i++) { |
| 367 | if (op == PREAD) { |
| 368 | *cp++ = w.pbyte[i]; |
| 369 | } else { |
| 370 | w.pbyte[i] = *cp++; |
| 371 | } |
| 372 | nbytes--; |
| 373 | } |
| 374 | if (op == PWRITE) { |
| 375 | store(p, seg, wordaddr, w.pword); |
| 376 | } |
| 377 | newaddr = wordaddr + sizeof(WORD); |
| 378 | } |
| 379 | byteoff = (nbytes&(~WMASK)); |
| 380 | nbytes -= byteoff; |
| 381 | bufend = cp + nbytes; |
| 382 | while (cp < bufend) { |
| 383 | if (op == PREAD) { |
| 384 | *((WORD *) cp) = fetch(p, seg, newaddr); |
| 385 | } else { |
| 386 | store(p, seg, newaddr, *((WORD *) cp)); |
| 387 | } |
| 388 | cp += sizeof(WORD); |
| 389 | newaddr += sizeof(WORD); |
| 390 | } |
| 391 | if (byteoff > 0) { |
| 392 | w.pword = fetch(p, seg, newaddr); |
| 393 | for (i = 0; i < byteoff; i++) { |
| 394 | if (op == PREAD) { |
| 395 | *cp++ = w.pbyte[i]; |
| 396 | } else { |
| 397 | w.pbyte[i] = *cp++; |
| 398 | } |
| 399 | } |
| 400 | if (op == PWRITE) { |
| 401 | store(p, seg, newaddr, w.pword); |
| 402 | } |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * Get a word from a process at the given address. |
| 408 | * The address is assumed to be on a word boundary. |
| 409 | * |
| 410 | * We use a simple cache scheme to avoid redundant references to |
| 411 | * the instruction space (which is assumed to be pure). In the |
| 412 | * case of px, the "instruction" space lies between ENDOFF and |
| 413 | * ENDOFF + objsize. |
| 414 | * |
| 415 | * It is necessary to use a write-through scheme so that |
| 416 | * breakpoints right next to each other don't interfere. |
| 417 | */ |
| 418 | |
| 419 | LOCAL WORD fetch(p, seg, addr) |
| 420 | PROCESS *p; |
| 421 | PIO_SEG seg; |
| 422 | register int addr; |
| 423 | { |
| 424 | register CACHEWORD *wp; |
| 425 | register WORD w; |
| 426 | |
| 427 | switch (seg) { |
| 428 | case TEXTSEG: |
| 429 | # if (isvaxpx) |
| 430 | panic("tried to fetch from px i-space"); |
| 431 | /* NOTREACHED */ |
| 432 | # else |
| 433 | wp = &p->word[cachehash(addr)]; |
| 434 | if (addr == 0 || wp->addr != addr) { |
| 435 | w = ptrace(IREAD, p->pid, addr, 0); |
| 436 | wp->addr = addr; |
| 437 | wp->val = w; |
| 438 | } else { |
| 439 | w = wp->val; |
| 440 | } |
| 441 | break; |
| 442 | # endif |
| 443 | |
| 444 | case DATASEG: |
| 445 | # if (isvaxpx) |
| 446 | if (addr >= ENDOFF && addr < ENDOFF + objsize) { |
| 447 | wp = &p->word[cachehash(addr)]; |
| 448 | if (addr == 0 || wp->addr != addr) { |
| 449 | w = ptrace(DREAD, p->pid, addr, 0); |
| 450 | wp->addr = addr; |
| 451 | wp->val = w; |
| 452 | } else { |
| 453 | w = wp->val; |
| 454 | } |
| 455 | } else { |
| 456 | w = ptrace(DREAD, p->pid, addr, 0); |
| 457 | } |
| 458 | # else |
| 459 | w = ptrace(DREAD, p->pid, addr, 0); |
| 460 | # endif |
| 461 | break; |
| 462 | |
| 463 | default: |
| 464 | panic("fetch: bad seg %d", seg); |
| 465 | /* NOTREACHED */ |
| 466 | } |
| 467 | return(w); |
| 468 | } |
| 469 | |
| 470 | /* |
| 471 | * Put a word into the process' address space at the given address. |
| 472 | * The address is assumed to be on a word boundary. |
| 473 | */ |
| 474 | |
| 475 | LOCAL store(p, seg, addr, data) |
| 476 | PROCESS *p; |
| 477 | PIO_SEG seg; |
| 478 | int addr; |
| 479 | WORD data; |
| 480 | { |
| 481 | register CACHEWORD *wp; |
| 482 | |
| 483 | switch (seg) { |
| 484 | case TEXTSEG: |
| 485 | wp = &p->word[cachehash(addr)]; |
| 486 | wp->addr = addr; |
| 487 | wp->val = data; |
| 488 | ptrace(IWRITE, p->pid, addr, data); |
| 489 | break; |
| 490 | |
| 491 | case DATASEG: |
| 492 | # if (isvaxpx) |
| 493 | if (addr >= ENDOFF && addr < ENDOFF + objsize) { |
| 494 | wp = &p->word[cachehash(addr)]; |
| 495 | wp->addr = addr; |
| 496 | wp->val = data; |
| 497 | } |
| 498 | # endif |
| 499 | ptrace(DWRITE, p->pid, addr, data); |
| 500 | break; |
| 501 | |
| 502 | default: |
| 503 | panic("store: bad seg %d", seg); |
| 504 | /*NOTREACHED*/ |
| 505 | } |
| 506 | } |
| 507 | |
| 508 | /* |
| 509 | * Initialize the instruction cache for a process. |
| 510 | * This is particularly necessary after the program has been remade. |
| 511 | */ |
| 512 | |
| 513 | initcache(process) |
| 514 | PROCESS *process; |
| 515 | { |
| 516 | register int i; |
| 517 | |
| 518 | for (i = 0; i < CSIZE; i++) { |
| 519 | process->word[i].addr = 0; |
| 520 | } |
| 521 | } |
| 522 | |
| 523 | /* |
| 524 | * Swap file numbers so as to redirect standard input and output. |
| 525 | */ |
| 526 | |
| 527 | LOCAL fswap(oldfd, newfd) |
| 528 | int oldfd; |
| 529 | int newfd; |
| 530 | { |
| 531 | if (oldfd != newfd) { |
| 532 | close(oldfd); |
| 533 | dup(newfd); |
| 534 | close(newfd); |
| 535 | } |
| 536 | } |