1 /* 2 * Copyright (c) 1991, 1992 Paul Kranenburg <pk (at) cs.few.eur.nl> 3 * Copyright (c) 1993 Branko Lankester <branko (at) hacktic.nl> 4 * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs (at) world.std.com> 5 * Copyright (c) 1996-1999 Wichert Akkerman <wichert (at) cistron.nl> 6 * Copyright (c) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation 7 * Linux for s390 port by D.J. Barrow 8 * <barrow_dj (at) mail.yahoo.com,djbarrow (at) de.ibm.com> 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include "defs.h" 35 #include "nsig.h" 36 37 /* The libc headers do not define this constant since it should only be 38 used by the implementation. So we define it here. */ 39 #ifndef SA_RESTORER 40 # ifdef ASM_SA_RESTORER 41 # define SA_RESTORER ASM_SA_RESTORER 42 # endif 43 #endif 44 45 /* 46 * Some architectures define SA_RESTORER in their headers, 47 * but do not actually have sa_restorer. 48 * 49 * Some architectures, otherwise, do not define SA_RESTORER in their headers, 50 * but actually have sa_restorer. 51 */ 52 #ifdef SA_RESTORER 53 # if defined HPPA || defined IA64 54 # define HAVE_SA_RESTORER 0 55 # else 56 # define HAVE_SA_RESTORER 1 57 # endif 58 #else /* !SA_RESTORER */ 59 # if defined SPARC || defined SPARC64 || defined M68K 60 # define HAVE_SA_RESTORER 1 61 # else 62 # define HAVE_SA_RESTORER 0 63 # endif 64 #endif 65 66 #include "xlat/sa_handler_values.h" 67 #include "xlat/sigact_flags.h" 68 #include "xlat/sigprocmaskcmds.h" 69 70 /* Anonymous realtime signals. */ 71 #ifndef ASM_SIGRTMIN 72 /* Linux kernel >= 3.18 defines SIGRTMIN to 32 on all architectures. */ 73 # define ASM_SIGRTMIN 32 74 #endif 75 #ifndef ASM_SIGRTMAX 76 /* Under glibc 2.1, SIGRTMAX et al are functions, but __SIGRTMAX is a 77 constant. This is what we want. Otherwise, just use SIGRTMAX. */ 78 # ifdef SIGRTMAX 79 # ifndef __SIGRTMAX 80 # define __SIGRTMAX SIGRTMAX 81 # endif 82 # endif 83 # ifdef __SIGRTMAX 84 # define ASM_SIGRTMAX __SIGRTMAX 85 # endif 86 #endif 87 88 /* Note on the size of sigset_t: 89 * 90 * In glibc, sigset_t is an array with space for 1024 bits (!), 91 * even though all arches supported by Linux have only 64 signals 92 * except MIPS, which has 128. IOW, it is 128 bytes long. 93 * 94 * In-kernel sigset_t is sized correctly (it is either 64 or 128 bit long). 95 * However, some old syscall return only 32 lower bits (one word). 96 * Example: sys_sigpending vs sys_rt_sigpending. 97 * 98 * Be aware of this fact when you try to 99 * memcpy(&tcp->u_arg[1], &something, sizeof(sigset_t)) 100 * - sizeof(sigset_t) is much bigger than you think, 101 * it may overflow tcp->u_arg[] array, and it may try to copy more data 102 * than is really available in <something>. 103 * Similarly, 104 * umoven(tcp, addr, sizeof(sigset_t), &sigset) 105 * may be a bad idea: it'll try to read much more data than needed 106 * to fetch a sigset_t. 107 * Use NSIG_BYTES as a size instead. 108 */ 109 110 static const char * 111 get_sa_handler_str(kernel_ulong_t handler) 112 { 113 return xlookup(sa_handler_values, handler); 114 } 115 116 static void 117 print_sa_handler(kernel_ulong_t handler) 118 { 119 const char *sa_handler_str = get_sa_handler_str(handler); 120 121 if (sa_handler_str) 122 tprints(sa_handler_str); 123 else 124 printaddr(handler); 125 } 126 127 const char * 128 signame(const int sig) 129 { 130 static char buf[sizeof("SIGRT_%u") + sizeof(int)*3]; 131 132 if (sig >= 0) { 133 const unsigned int s = sig; 134 135 if (s < nsignals) 136 return signalent[s]; 137 #ifdef ASM_SIGRTMAX 138 if (s >= ASM_SIGRTMIN && s <= (unsigned int) ASM_SIGRTMAX) { 139 sprintf(buf, "SIGRT_%u", s - ASM_SIGRTMIN); 140 return buf; 141 } 142 #endif 143 } 144 sprintf(buf, "%d", sig); 145 return buf; 146 } 147 148 static unsigned int 149 popcount32(const uint32_t *a, unsigned int size) 150 { 151 unsigned int count = 0; 152 153 for (; size; ++a, --size) { 154 uint32_t x = *a; 155 156 #ifdef HAVE___BUILTIN_POPCOUNT 157 count += __builtin_popcount(x); 158 #else 159 for (; x; ++count) 160 x &= x - 1; 161 #endif 162 } 163 164 return count; 165 } 166 167 const char * 168 sprintsigmask_n(const char *prefix, const void *sig_mask, unsigned int bytes) 169 { 170 /* 171 * The maximum number of signal names to be printed 172 * is NSIG_BYTES * 8 * 2 / 3. 173 * Most of signal names have length 7, 174 * average length of signal names is less than 7. 175 * The length of prefix string does not exceed 16. 176 */ 177 static char outstr[128 + 8 * (NSIG_BYTES * 8 * 2 / 3)]; 178 179 char *s; 180 const uint32_t *mask; 181 uint32_t inverted_mask[NSIG_BYTES / 4]; 182 unsigned int size; 183 int i; 184 char sep; 185 186 s = stpcpy(outstr, prefix); 187 188 mask = sig_mask; 189 /* length of signal mask in 4-byte words */ 190 size = (bytes >= NSIG_BYTES) ? NSIG_BYTES / 4 : (bytes + 3) / 4; 191 192 /* check whether 2/3 or more bits are set */ 193 if (popcount32(mask, size) >= size * (4 * 8) * 2 / 3) { 194 /* show those signals that are NOT in the mask */ 195 unsigned int j; 196 for (j = 0; j < size; ++j) 197 inverted_mask[j] = ~mask[j]; 198 mask = inverted_mask; 199 *s++ = '~'; 200 } 201 202 sep = '['; 203 for (i = 0; (i = next_set_bit(mask, i, size * (4 * 8))) >= 0; ) { 204 ++i; 205 *s++ = sep; 206 if ((unsigned) i < nsignals) { 207 s = stpcpy(s, signalent[i] + 3); 208 } 209 #ifdef ASM_SIGRTMAX 210 else if (i >= ASM_SIGRTMIN && i <= ASM_SIGRTMAX) { 211 s += sprintf(s, "RT_%u", i - ASM_SIGRTMIN); 212 } 213 #endif 214 else { 215 s += sprintf(s, "%u", i); 216 } 217 sep = ' '; 218 } 219 if (sep == '[') 220 *s++ = sep; 221 *s++ = ']'; 222 *s = '\0'; 223 return outstr; 224 } 225 226 #define sprintsigmask_val(prefix, mask) \ 227 sprintsigmask_n((prefix), &(mask), sizeof(mask)) 228 229 #define tprintsigmask_val(prefix, mask) \ 230 tprints(sprintsigmask_n((prefix), &(mask), sizeof(mask))) 231 232 void 233 printsignal(int nr) 234 { 235 tprints(signame(nr)); 236 } 237 238 static void 239 print_sigset_addr_len_limit(struct tcb *const tcp, const kernel_ulong_t addr, 240 const kernel_ulong_t len, const unsigned int min_len) 241 { 242 /* 243 * Here len is usually equal to NSIG_BYTES or current_wordsize. 244 * But we code this defensively: 245 */ 246 if (len < min_len || len > NSIG_BYTES) { 247 printaddr(addr); 248 return; 249 } 250 int mask[NSIG_BYTES / sizeof(int)] = {}; 251 if (umoven_or_printaddr(tcp, addr, len, mask)) 252 return; 253 tprints(sprintsigmask_n("", mask, len)); 254 } 255 256 void 257 print_sigset_addr_len(struct tcb *const tcp, const kernel_ulong_t addr, 258 const kernel_ulong_t len) 259 { 260 print_sigset_addr_len_limit(tcp, addr, len, current_wordsize); 261 } 262 263 SYS_FUNC(sigsetmask) 264 { 265 if (entering(tcp)) { 266 tprintsigmask_val("", tcp->u_arg[0]); 267 } 268 else if (!syserror(tcp)) { 269 tcp->auxstr = sprintsigmask_val("old mask ", tcp->u_rval); 270 return RVAL_HEX | RVAL_STR; 271 } 272 return 0; 273 } 274 275 struct old_sigaction { 276 /* sa_handler may be a libc #define, need to use other name: */ 277 #ifdef MIPS 278 unsigned int sa_flags; 279 unsigned long sa_handler__; 280 /* Kernel treats sa_mask as an array of longs. */ 281 unsigned long sa_mask[NSIG / sizeof(long)]; 282 #else 283 unsigned long sa_handler__; 284 unsigned long sa_mask; 285 unsigned long sa_flags; 286 #endif /* !MIPS */ 287 #if HAVE_SA_RESTORER 288 unsigned long sa_restorer; 289 #endif 290 }; 291 292 struct old_sigaction32 { 293 /* sa_handler may be a libc #define, need to use other name: */ 294 uint32_t sa_handler__; 295 uint32_t sa_mask; 296 uint32_t sa_flags; 297 #if HAVE_SA_RESTORER 298 uint32_t sa_restorer; 299 #endif 300 }; 301 302 static void 303 decode_old_sigaction(struct tcb *const tcp, const kernel_ulong_t addr) 304 { 305 struct old_sigaction sa; 306 307 #ifndef current_wordsize 308 if (current_wordsize < sizeof(sa.sa_handler__)) { 309 struct old_sigaction32 sa32; 310 311 if (umove_or_printaddr(tcp, addr, &sa32)) 312 return; 313 314 memset(&sa, 0, sizeof(sa)); 315 sa.sa_handler__ = sa32.sa_handler__; 316 sa.sa_flags = sa32.sa_flags; 317 #if HAVE_SA_RESTORER && defined SA_RESTORER 318 sa.sa_restorer = sa32.sa_restorer; 319 #endif 320 sa.sa_mask = sa32.sa_mask; 321 } else 322 #endif 323 if (umove_or_printaddr(tcp, addr, &sa)) 324 return; 325 326 tprints("{sa_handler="); 327 print_sa_handler(sa.sa_handler__); 328 tprints(", sa_mask="); 329 #ifdef MIPS 330 tprintsigmask_addr("", sa.sa_mask); 331 #else 332 tprintsigmask_val("", sa.sa_mask); 333 #endif 334 tprints(", sa_flags="); 335 printflags(sigact_flags, sa.sa_flags, "SA_???"); 336 #if HAVE_SA_RESTORER && defined SA_RESTORER 337 if (sa.sa_flags & SA_RESTORER) { 338 tprints(", sa_restorer="); 339 printaddr(sa.sa_restorer); 340 } 341 #endif 342 tprints("}"); 343 } 344 345 SYS_FUNC(sigaction) 346 { 347 if (entering(tcp)) { 348 printsignal(tcp->u_arg[0]); 349 tprints(", "); 350 decode_old_sigaction(tcp, tcp->u_arg[1]); 351 tprints(", "); 352 } else 353 decode_old_sigaction(tcp, tcp->u_arg[2]); 354 return 0; 355 } 356 357 SYS_FUNC(signal) 358 { 359 if (entering(tcp)) { 360 printsignal(tcp->u_arg[0]); 361 tprints(", "); 362 print_sa_handler(tcp->u_arg[1]); 363 return 0; 364 } else if (!syserror(tcp)) { 365 tcp->auxstr = get_sa_handler_str(tcp->u_rval); 366 return RVAL_HEX | RVAL_STR; 367 } 368 return 0; 369 } 370 371 SYS_FUNC(siggetmask) 372 { 373 if (exiting(tcp)) { 374 tcp->auxstr = sprintsigmask_val("mask ", tcp->u_rval); 375 } 376 return RVAL_HEX | RVAL_STR; 377 } 378 379 SYS_FUNC(sigsuspend) 380 { 381 tprintsigmask_val("", tcp->u_arg[2]); 382 383 return RVAL_DECODED; 384 } 385 386 /* "Old" sigprocmask, which operates with word-sized signal masks */ 387 SYS_FUNC(sigprocmask) 388 { 389 # ifdef ALPHA 390 if (entering(tcp)) { 391 /* 392 * Alpha/OSF is different: it doesn't pass in two pointers, 393 * but rather passes in the new bitmask as an argument and 394 * then returns the old bitmask. This "works" because we 395 * only have 64 signals to worry about. If you want more, 396 * use of the rt_sigprocmask syscall is required. 397 * Alpha: 398 * old = osf_sigprocmask(how, new); 399 * Everyone else: 400 * ret = sigprocmask(how, &new, &old, ...); 401 */ 402 printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???"); 403 tprintsigmask_val(", ", tcp->u_arg[1]); 404 } 405 else if (!syserror(tcp)) { 406 tcp->auxstr = sprintsigmask_val("old mask ", tcp->u_rval); 407 return RVAL_HEX | RVAL_STR; 408 } 409 # else /* !ALPHA */ 410 if (entering(tcp)) { 411 printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???"); 412 tprints(", "); 413 print_sigset_addr_len(tcp, tcp->u_arg[1], current_wordsize); 414 tprints(", "); 415 } 416 else { 417 print_sigset_addr_len(tcp, tcp->u_arg[2], current_wordsize); 418 } 419 # endif /* !ALPHA */ 420 return 0; 421 } 422 423 SYS_FUNC(kill) 424 { 425 tprintf("%d, %s", 426 (int) tcp->u_arg[0], 427 signame(tcp->u_arg[1])); 428 429 return RVAL_DECODED; 430 } 431 432 SYS_FUNC(tgkill) 433 { 434 tprintf("%d, %d, %s", 435 (int) tcp->u_arg[0], 436 (int) tcp->u_arg[1], 437 signame(tcp->u_arg[2])); 438 439 return RVAL_DECODED; 440 } 441 442 SYS_FUNC(sigpending) 443 { 444 if (exiting(tcp)) 445 print_sigset_addr_len(tcp, tcp->u_arg[0], current_wordsize); 446 return 0; 447 } 448 449 SYS_FUNC(rt_sigprocmask) 450 { 451 /* Note: arg[3] is the length of the sigset. Kernel requires NSIG_BYTES */ 452 if (entering(tcp)) { 453 printxval(sigprocmaskcmds, tcp->u_arg[0], "SIG_???"); 454 tprints(", "); 455 print_sigset_addr_len(tcp, tcp->u_arg[1], tcp->u_arg[3]); 456 tprints(", "); 457 } 458 else { 459 print_sigset_addr_len(tcp, tcp->u_arg[2], tcp->u_arg[3]); 460 tprintf(", %" PRI_klu, tcp->u_arg[3]); 461 } 462 return 0; 463 } 464 465 /* Structure describing the action to be taken when a signal arrives. */ 466 struct new_sigaction 467 { 468 /* sa_handler may be a libc #define, need to use other name: */ 469 #ifdef MIPS 470 unsigned int sa_flags; 471 unsigned long sa_handler__; 472 #else 473 unsigned long sa_handler__; 474 unsigned long sa_flags; 475 #endif /* !MIPS */ 476 #if HAVE_SA_RESTORER 477 unsigned long sa_restorer; 478 #endif 479 /* Kernel treats sa_mask as an array of longs. */ 480 unsigned long sa_mask[NSIG / sizeof(long)]; 481 }; 482 /* Same for i386-on-x86_64 and similar cases */ 483 struct new_sigaction32 484 { 485 uint32_t sa_handler__; 486 uint32_t sa_flags; 487 #if HAVE_SA_RESTORER 488 uint32_t sa_restorer; 489 #endif 490 uint32_t sa_mask[2 * (NSIG / sizeof(long))]; 491 }; 492 493 static void 494 decode_new_sigaction(struct tcb *const tcp, const kernel_ulong_t addr) 495 { 496 struct new_sigaction sa; 497 498 #ifndef current_wordsize 499 if (current_wordsize < sizeof(sa.sa_handler__)) { 500 struct new_sigaction32 sa32; 501 502 if (umove_or_printaddr(tcp, addr, &sa32)) 503 return; 504 505 memset(&sa, 0, sizeof(sa)); 506 sa.sa_handler__ = sa32.sa_handler__; 507 sa.sa_flags = sa32.sa_flags; 508 #if HAVE_SA_RESTORER && defined SA_RESTORER 509 sa.sa_restorer = sa32.sa_restorer; 510 #endif 511 /* Kernel treats sa_mask as an array of longs. 512 * For 32-bit process, "long" is uint32_t, thus, for example, 513 * 32th bit in sa_mask will end up as bit 0 in sa_mask[1]. 514 * But for (64-bit) kernel, 32th bit in sa_mask is 515 * 32th bit in 0th (64-bit) long! 516 * For little-endian, it's the same. 517 * For big-endian, we swap 32-bit words. 518 */ 519 sa.sa_mask[0] = ULONG_LONG(sa32.sa_mask[0], sa32.sa_mask[1]); 520 } else 521 #endif 522 if (umove_or_printaddr(tcp, addr, &sa)) 523 return; 524 525 tprints("{sa_handler="); 526 print_sa_handler(sa.sa_handler__); 527 tprints(", sa_mask="); 528 /* 529 * Sigset size is in tcp->u_arg[4] (SPARC) 530 * or in tcp->u_arg[3] (all other), 531 * but kernel won't handle sys_rt_sigaction 532 * with wrong sigset size (just returns EINVAL instead). 533 * We just fetch the right size, which is NSIG_BYTES. 534 */ 535 tprintsigmask_val("", sa.sa_mask); 536 tprints(", sa_flags="); 537 538 printflags(sigact_flags, sa.sa_flags, "SA_???"); 539 #if HAVE_SA_RESTORER && defined SA_RESTORER 540 if (sa.sa_flags & SA_RESTORER) { 541 tprints(", sa_restorer="); 542 printaddr(sa.sa_restorer); 543 } 544 #endif 545 tprints("}"); 546 } 547 548 SYS_FUNC(rt_sigaction) 549 { 550 if (entering(tcp)) { 551 printsignal(tcp->u_arg[0]); 552 tprints(", "); 553 decode_new_sigaction(tcp, tcp->u_arg[1]); 554 tprints(", "); 555 } else { 556 decode_new_sigaction(tcp, tcp->u_arg[2]); 557 #if defined(SPARC) || defined(SPARC64) 558 tprintf(", %#" PRI_klx ", %" PRI_klu, tcp->u_arg[3], tcp->u_arg[4]); 559 #elif defined(ALPHA) 560 tprintf(", %" PRI_klu ", %#" PRI_klx, tcp->u_arg[3], tcp->u_arg[4]); 561 #else 562 tprintf(", %" PRI_klu, tcp->u_arg[3]); 563 #endif 564 } 565 return 0; 566 } 567 568 SYS_FUNC(rt_sigpending) 569 { 570 if (exiting(tcp)) { 571 /* 572 * One of the few syscalls where sigset size (arg[1]) 573 * is allowed to be <= NSIG_BYTES, not strictly ==. 574 * This allows non-rt sigpending() syscall 575 * to reuse rt_sigpending() code in kernel. 576 */ 577 print_sigset_addr_len_limit(tcp, tcp->u_arg[0], 578 tcp->u_arg[1], 1); 579 tprintf(", %" PRI_klu, tcp->u_arg[1]); 580 } 581 return 0; 582 } 583 584 SYS_FUNC(rt_sigsuspend) 585 { 586 /* NB: kernel requires arg[1] == NSIG_BYTES */ 587 print_sigset_addr_len(tcp, tcp->u_arg[0], tcp->u_arg[1]); 588 tprintf(", %" PRI_klu, tcp->u_arg[1]); 589 590 return RVAL_DECODED; 591 } 592 593 static void 594 print_sigqueueinfo(struct tcb *const tcp, const int sig, 595 const kernel_ulong_t addr) 596 { 597 printsignal(sig); 598 tprints(", "); 599 printsiginfo_at(tcp, addr); 600 } 601 602 SYS_FUNC(rt_sigqueueinfo) 603 { 604 tprintf("%d, ", (int) tcp->u_arg[0]); 605 print_sigqueueinfo(tcp, tcp->u_arg[1], tcp->u_arg[2]); 606 607 return RVAL_DECODED; 608 } 609 610 SYS_FUNC(rt_tgsigqueueinfo) 611 { 612 tprintf("%d, %d, ", (int) tcp->u_arg[0], (int) tcp->u_arg[1]); 613 print_sigqueueinfo(tcp, tcp->u_arg[2], tcp->u_arg[3]); 614 615 return RVAL_DECODED; 616 } 617 618 SYS_FUNC(rt_sigtimedwait) 619 { 620 /* NB: kernel requires arg[3] == NSIG_BYTES */ 621 if (entering(tcp)) { 622 print_sigset_addr_len(tcp, tcp->u_arg[0], tcp->u_arg[3]); 623 tprints(", "); 624 if (!(tcp->u_arg[1] && verbose(tcp))) { 625 /* 626 * This is the only "return" parameter, 627 * if we are not going to fetch it on exit, 628 * decode all parameters on entry. 629 */ 630 printaddr(tcp->u_arg[1]); 631 tprints(", "); 632 print_timespec(tcp, tcp->u_arg[2]); 633 tprintf(", %" PRI_klu, tcp->u_arg[3]); 634 } else { 635 char *sts = xstrdup(sprint_timespec(tcp, tcp->u_arg[2])); 636 set_tcb_priv_data(tcp, sts, free); 637 } 638 } else { 639 if (tcp->u_arg[1] && verbose(tcp)) { 640 printsiginfo_at(tcp, tcp->u_arg[1]); 641 tprints(", "); 642 tprints(get_tcb_priv_data(tcp)); 643 tprintf(", %" PRI_klu, tcp->u_arg[3]); 644 } 645 646 if (!syserror(tcp) && tcp->u_rval) { 647 tcp->auxstr = signame(tcp->u_rval); 648 return RVAL_STR; 649 } 650 } 651 return 0; 652 }; 653 654 SYS_FUNC(restart_syscall) 655 { 656 tprintf("<... resuming interrupted %s ...>", 657 tcp->s_prev_ent ? tcp->s_prev_ent->sys_name : "system call"); 658 659 return RVAL_DECODED; 660 } 661
