1 /* Low-level child interface to ptrace. 2 3 Copyright (C) 1988-1996, 1998-2002, 2004-2012 Free Software 4 Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "command.h" 23 #include "inferior.h" 24 #include "inflow.h" 25 #include "terminal.h" 26 #include "gdbcore.h" 27 #include "regcache.h" 28 29 #include "gdb_assert.h" 30 #include "gdb_string.h" 31 #include "gdb_ptrace.h" 32 #include "gdb_wait.h" 33 #include <signal.h> 34 35 #include "inf-ptrace.h" 36 #include "inf-child.h" 37 #include "gdbthread.h" 38 39 40 41 #ifdef PT_GET_PROCESS_STATE 42 43 static int 44 inf_ptrace_follow_fork (struct target_ops *ops, int follow_child) 45 { 46 pid_t pid, fpid; 47 ptrace_state_t pe; 48 49 pid = ptid_get_pid (inferior_ptid); 50 51 if (ptrace (PT_GET_PROCESS_STATE, pid, 52 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 53 perror_with_name (("ptrace")); 54 55 gdb_assert (pe.pe_report_event == PTRACE_FORK); 56 fpid = pe.pe_other_pid; 57 58 if (follow_child) 59 { 60 struct inferior *parent_inf, *child_inf; 61 struct thread_info *tp; 62 63 parent_inf = find_inferior_pid (pid); 64 65 /* Add the child. */ 66 child_inf = add_inferior (fpid); 67 child_inf->attach_flag = parent_inf->attach_flag; 68 copy_terminal_info (child_inf, parent_inf); 69 child_inf->pspace = parent_inf->pspace; 70 child_inf->aspace = parent_inf->aspace; 71 72 /* Before detaching from the parent, remove all breakpoints from 73 it. */ 74 remove_breakpoints (); 75 76 if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1) 77 perror_with_name (("ptrace")); 78 79 /* Switch inferior_ptid out of the parent's way. */ 80 inferior_ptid = pid_to_ptid (fpid); 81 82 /* Delete the parent. */ 83 detach_inferior (pid); 84 85 add_thread_silent (inferior_ptid); 86 } 87 else 88 { 89 /* Breakpoints have already been detached from the child by 90 infrun.c. */ 91 92 if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1) 93 perror_with_name (("ptrace")); 94 } 95 96 return 0; 97 } 98 99 #endif /* PT_GET_PROCESS_STATE */ 100 101 102 /* Prepare to be traced. */ 103 104 static void 105 inf_ptrace_me (void) 106 { 107 /* "Trace me, Dr. Memory!" */ 108 ptrace (PT_TRACE_ME, 0, (PTRACE_TYPE_ARG3)0, 0); 109 } 110 111 /* Start a new inferior Unix child process. EXEC_FILE is the file to 112 run, ALLARGS is a string containing the arguments to the program. 113 ENV is the environment vector to pass. If FROM_TTY is non-zero, be 114 chatty about it. */ 115 116 static void 117 inf_ptrace_create_inferior (struct target_ops *ops, 118 char *exec_file, char *allargs, char **env, 119 int from_tty) 120 { 121 int pid; 122 123 /* Do not change either targets above or the same target if already present. 124 The reason is the target stack is shared across multiple inferiors. */ 125 int ops_already_pushed = target_is_pushed (ops); 126 struct cleanup *back_to = NULL; 127 128 if (! ops_already_pushed) 129 { 130 /* Clear possible core file with its process_stratum. */ 131 push_target (ops); 132 back_to = make_cleanup_unpush_target (ops); 133 } 134 135 pid = fork_inferior (exec_file, allargs, env, inf_ptrace_me, NULL, 136 NULL, NULL, NULL); 137 138 if (! ops_already_pushed) 139 discard_cleanups (back_to); 140 141 /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h, and will 142 be 1 or 2 depending on whether we're starting without or with a 143 shell. */ 144 startup_inferior (START_INFERIOR_TRAPS_EXPECTED); 145 146 /* On some targets, there must be some explicit actions taken after 147 the inferior has been started up. */ 148 target_post_startup_inferior (pid_to_ptid (pid)); 149 } 150 151 #ifdef PT_GET_PROCESS_STATE 152 153 static void 154 inf_ptrace_post_startup_inferior (ptid_t pid) 155 { 156 ptrace_event_t pe; 157 158 /* Set the initial event mask. */ 159 memset (&pe, 0, sizeof pe); 160 pe.pe_set_event |= PTRACE_FORK; 161 if (ptrace (PT_SET_EVENT_MASK, ptid_get_pid (pid), 162 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 163 perror_with_name (("ptrace")); 164 } 165 166 #endif 167 168 /* Clean up a rotting corpse of an inferior after it died. */ 169 170 static void 171 inf_ptrace_mourn_inferior (struct target_ops *ops) 172 { 173 int status; 174 175 /* Wait just one more time to collect the inferior's exit status. 176 Do not check whether this succeeds though, since we may be 177 dealing with a process that we attached to. Such a process will 178 only report its exit status to its original parent. */ 179 waitpid (ptid_get_pid (inferior_ptid), &status, 0); 180 181 generic_mourn_inferior (); 182 183 if (!have_inferiors ()) 184 unpush_target (ops); 185 } 186 187 /* Attach to the process specified by ARGS. If FROM_TTY is non-zero, 188 be chatty about it. */ 189 190 static void 191 inf_ptrace_attach (struct target_ops *ops, char *args, int from_tty) 192 { 193 char *exec_file; 194 pid_t pid; 195 struct inferior *inf; 196 197 /* Do not change either targets above or the same target if already present. 198 The reason is the target stack is shared across multiple inferiors. */ 199 int ops_already_pushed = target_is_pushed (ops); 200 struct cleanup *back_to = NULL; 201 202 pid = parse_pid_to_attach (args); 203 204 if (pid == getpid ()) /* Trying to masturbate? */ 205 error (_("I refuse to debug myself!")); 206 207 if (! ops_already_pushed) 208 { 209 /* target_pid_to_str already uses the target. Also clear possible core 210 file with its process_stratum. */ 211 push_target (ops); 212 back_to = make_cleanup_unpush_target (ops); 213 } 214 215 if (from_tty) 216 { 217 exec_file = get_exec_file (0); 218 219 if (exec_file) 220 printf_unfiltered (_("Attaching to program: %s, %s\n"), exec_file, 221 target_pid_to_str (pid_to_ptid (pid))); 222 else 223 printf_unfiltered (_("Attaching to %s\n"), 224 target_pid_to_str (pid_to_ptid (pid))); 225 226 gdb_flush (gdb_stdout); 227 } 228 229 #ifdef PT_ATTACH 230 errno = 0; 231 ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3)0, 0); 232 if (errno != 0) 233 perror_with_name (("ptrace")); 234 #else 235 error (_("This system does not support attaching to a process")); 236 #endif 237 238 inf = current_inferior (); 239 inferior_appeared (inf, pid); 240 inf->attach_flag = 1; 241 inferior_ptid = pid_to_ptid (pid); 242 243 /* Always add a main thread. If some target extends the ptrace 244 target, it should decorate the ptid later with more info. */ 245 add_thread_silent (inferior_ptid); 246 247 if (! ops_already_pushed) 248 discard_cleanups (back_to); 249 } 250 251 #ifdef PT_GET_PROCESS_STATE 252 253 void 254 inf_ptrace_post_attach (int pid) 255 { 256 ptrace_event_t pe; 257 258 /* Set the initial event mask. */ 259 memset (&pe, 0, sizeof pe); 260 pe.pe_set_event |= PTRACE_FORK; 261 if (ptrace (PT_SET_EVENT_MASK, pid, 262 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 263 perror_with_name (("ptrace")); 264 } 265 266 #endif 267 268 /* Detach from the inferior, optionally passing it the signal 269 specified by ARGS. If FROM_TTY is non-zero, be chatty about it. */ 270 271 static void 272 inf_ptrace_detach (struct target_ops *ops, char *args, int from_tty) 273 { 274 pid_t pid = ptid_get_pid (inferior_ptid); 275 int sig = 0; 276 277 if (from_tty) 278 { 279 char *exec_file = get_exec_file (0); 280 if (exec_file == 0) 281 exec_file = ""; 282 printf_unfiltered (_("Detaching from program: %s, %s\n"), exec_file, 283 target_pid_to_str (pid_to_ptid (pid))); 284 gdb_flush (gdb_stdout); 285 } 286 if (args) 287 sig = atoi (args); 288 289 #ifdef PT_DETACH 290 /* We'd better not have left any breakpoints in the program or it'll 291 die when it hits one. Also note that this may only work if we 292 previously attached to the inferior. It *might* work if we 293 started the process ourselves. */ 294 errno = 0; 295 ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, sig); 296 if (errno != 0) 297 perror_with_name (("ptrace")); 298 #else 299 error (_("This system does not support detaching from a process")); 300 #endif 301 302 inferior_ptid = null_ptid; 303 detach_inferior (pid); 304 305 if (!have_inferiors ()) 306 unpush_target (ops); 307 } 308 309 /* Kill the inferior. */ 310 311 static void 312 inf_ptrace_kill (struct target_ops *ops) 313 { 314 pid_t pid = ptid_get_pid (inferior_ptid); 315 int status; 316 317 if (pid == FAKE_PROCESS_ID) 318 return; 319 320 ptrace (PT_KILL, pid, (PTRACE_TYPE_ARG3)0, 0); 321 waitpid (pid, &status, 0); 322 323 target_mourn_inferior (); 324 } 325 326 /* Stop the inferior. */ 327 328 static void 329 inf_ptrace_stop (ptid_t ptid) 330 { 331 /* Send a SIGINT to the process group. This acts just like the user 332 typed a ^C on the controlling terminal. Note that using a 333 negative process number in kill() is a System V-ism. The proper 334 BSD interface is killpg(). However, all modern BSDs support the 335 System V interface too. */ 336 kill (-inferior_process_group (), SIGINT); 337 } 338 339 /* Resume execution of thread PTID, or all threads if PTID is -1. If 340 STEP is nonzero, single-step it. If SIGNAL is nonzero, give it 341 that signal. */ 342 343 static void 344 inf_ptrace_resume (struct target_ops *ops, 345 ptid_t ptid, int step, enum target_signal signal) 346 { 347 pid_t pid = ptid_get_pid (ptid); 348 int request; 349 350 if (pid == -1) 351 /* Resume all threads. Traditionally ptrace() only supports 352 single-threaded processes, so simply resume the inferior. */ 353 pid = ptid_get_pid (inferior_ptid); 354 355 if (catch_syscall_enabled () > 0) 356 request = PT_SYSCALL; 357 else 358 request = PT_CONTINUE; 359 360 if (step) 361 { 362 /* If this system does not support PT_STEP, a higher level 363 function will have called single_step() to transmute the step 364 request into a continue request (by setting breakpoints on 365 all possible successor instructions), so we don't have to 366 worry about that here. */ 367 request = PT_STEP; 368 } 369 370 /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from 371 where it was. If GDB wanted it to start some other way, we have 372 already written a new program counter value to the child. */ 373 errno = 0; 374 ptrace (request, pid, (PTRACE_TYPE_ARG3)1, target_signal_to_host (signal)); 375 if (errno != 0) 376 perror_with_name (("ptrace")); 377 } 378 379 /* Wait for the child specified by PTID to do something. Return the 380 process ID of the child, or MINUS_ONE_PTID in case of error; store 381 the status in *OURSTATUS. */ 382 383 static ptid_t 384 inf_ptrace_wait (struct target_ops *ops, 385 ptid_t ptid, struct target_waitstatus *ourstatus, int options) 386 { 387 pid_t pid; 388 int status, save_errno; 389 390 do 391 { 392 set_sigint_trap (); 393 394 do 395 { 396 pid = waitpid (ptid_get_pid (ptid), &status, 0); 397 save_errno = errno; 398 } 399 while (pid == -1 && errno == EINTR); 400 401 clear_sigint_trap (); 402 403 if (pid == -1) 404 { 405 fprintf_unfiltered (gdb_stderr, 406 _("Child process unexpectedly missing: %s.\n"), 407 safe_strerror (save_errno)); 408 409 /* Claim it exited with unknown signal. */ 410 ourstatus->kind = TARGET_WAITKIND_SIGNALLED; 411 ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; 412 return inferior_ptid; 413 } 414 415 /* Ignore terminated detached child processes. */ 416 if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid)) 417 pid = -1; 418 } 419 while (pid == -1); 420 421 #ifdef PT_GET_PROCESS_STATE 422 if (WIFSTOPPED (status)) 423 { 424 ptrace_state_t pe; 425 pid_t fpid; 426 427 if (ptrace (PT_GET_PROCESS_STATE, pid, 428 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 429 perror_with_name (("ptrace")); 430 431 switch (pe.pe_report_event) 432 { 433 case PTRACE_FORK: 434 ourstatus->kind = TARGET_WAITKIND_FORKED; 435 ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid); 436 437 /* Make sure the other end of the fork is stopped too. */ 438 fpid = waitpid (pe.pe_other_pid, &status, 0); 439 if (fpid == -1) 440 perror_with_name (("waitpid")); 441 442 if (ptrace (PT_GET_PROCESS_STATE, fpid, 443 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 444 perror_with_name (("ptrace")); 445 446 gdb_assert (pe.pe_report_event == PTRACE_FORK); 447 gdb_assert (pe.pe_other_pid == pid); 448 if (fpid == ptid_get_pid (inferior_ptid)) 449 { 450 ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid); 451 return pid_to_ptid (fpid); 452 } 453 454 return pid_to_ptid (pid); 455 } 456 } 457 #endif 458 459 store_waitstatus (ourstatus, status); 460 return pid_to_ptid (pid); 461 } 462 463 /* Attempt a transfer all LEN bytes starting at OFFSET between the 464 inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer. 465 Return the number of bytes actually transferred. */ 466 467 static LONGEST 468 inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object, 469 const char *annex, gdb_byte *readbuf, 470 const gdb_byte *writebuf, 471 ULONGEST offset, LONGEST len) 472 { 473 pid_t pid = ptid_get_pid (inferior_ptid); 474 475 switch (object) 476 { 477 case TARGET_OBJECT_MEMORY: 478 #ifdef PT_IO 479 /* OpenBSD 3.1, NetBSD 1.6 and FreeBSD 5.0 have a new PT_IO 480 request that promises to be much more efficient in reading 481 and writing data in the traced process's address space. */ 482 { 483 struct ptrace_io_desc piod; 484 485 /* NOTE: We assume that there are no distinct address spaces 486 for instruction and data. However, on OpenBSD 3.9 and 487 later, PIOD_WRITE_D doesn't allow changing memory that's 488 mapped read-only. Since most code segments will be 489 read-only, using PIOD_WRITE_D will prevent us from 490 inserting breakpoints, so we use PIOD_WRITE_I instead. */ 491 piod.piod_op = writebuf ? PIOD_WRITE_I : PIOD_READ_D; 492 piod.piod_addr = writebuf ? (void *) writebuf : readbuf; 493 piod.piod_offs = (void *) (long) offset; 494 piod.piod_len = len; 495 496 errno = 0; 497 if (ptrace (PT_IO, pid, (caddr_t)&piod, 0) == 0) 498 /* Return the actual number of bytes read or written. */ 499 return piod.piod_len; 500 /* If the PT_IO request is somehow not supported, fallback on 501 using PT_WRITE_D/PT_READ_D. Otherwise we will return zero 502 to indicate failure. */ 503 if (errno != EINVAL) 504 return 0; 505 } 506 #endif 507 { 508 union 509 { 510 PTRACE_TYPE_RET word; 511 gdb_byte byte[sizeof (PTRACE_TYPE_RET)]; 512 } buffer; 513 ULONGEST rounded_offset; 514 LONGEST partial_len; 515 516 /* Round the start offset down to the next long word 517 boundary. */ 518 rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET); 519 520 /* Since ptrace will transfer a single word starting at that 521 rounded_offset the partial_len needs to be adjusted down to 522 that (remember this function only does a single transfer). 523 Should the required length be even less, adjust it down 524 again. */ 525 partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset; 526 if (partial_len > len) 527 partial_len = len; 528 529 if (writebuf) 530 { 531 /* If OFFSET:PARTIAL_LEN is smaller than 532 ROUNDED_OFFSET:WORDSIZE then a read/modify write will 533 be needed. Read in the entire word. */ 534 if (rounded_offset < offset 535 || (offset + partial_len 536 < rounded_offset + sizeof (PTRACE_TYPE_RET))) 537 /* Need part of initial word -- fetch it. */ 538 buffer.word = ptrace (PT_READ_I, pid, 539 (PTRACE_TYPE_ARG3)(uintptr_t) 540 rounded_offset, 0); 541 542 /* Copy data to be written over corresponding part of 543 buffer. */ 544 memcpy (buffer.byte + (offset - rounded_offset), 545 writebuf, partial_len); 546 547 errno = 0; 548 ptrace (PT_WRITE_D, pid, 549 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 550 buffer.word); 551 if (errno) 552 { 553 /* Using the appropriate one (I or D) is necessary for 554 Gould NP1, at least. */ 555 errno = 0; 556 ptrace (PT_WRITE_I, pid, 557 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 558 buffer.word); 559 if (errno) 560 return 0; 561 } 562 } 563 564 if (readbuf) 565 { 566 errno = 0; 567 buffer.word = ptrace (PT_READ_I, pid, 568 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 569 0); 570 if (errno) 571 return 0; 572 /* Copy appropriate bytes out of the buffer. */ 573 memcpy (readbuf, buffer.byte + (offset - rounded_offset), 574 partial_len); 575 } 576 577 return partial_len; 578 } 579 580 case TARGET_OBJECT_UNWIND_TABLE: 581 return -1; 582 583 case TARGET_OBJECT_AUXV: 584 return -1; 585 586 case TARGET_OBJECT_WCOOKIE: 587 return -1; 588 589 default: 590 return -1; 591 } 592 } 593 594 /* Return non-zero if the thread specified by PTID is alive. */ 595 596 static int 597 inf_ptrace_thread_alive (struct target_ops *ops, ptid_t ptid) 598 { 599 /* ??? Is kill the right way to do this? */ 600 return (kill (ptid_get_pid (ptid), 0) != -1); 601 } 602 603 /* Print status information about what we're accessing. */ 604 605 static void 606 inf_ptrace_files_info (struct target_ops *ignore) 607 { 608 struct inferior *inf = current_inferior (); 609 610 printf_filtered (_("\tUsing the running image of %s %s.\n"), 611 inf->attach_flag ? "attached" : "child", 612 target_pid_to_str (inferior_ptid)); 613 } 614 615 static char * 616 inf_ptrace_pid_to_str (struct target_ops *ops, ptid_t ptid) 617 { 618 return normal_pid_to_str (ptid); 619 } 620 621 /* Create a prototype ptrace target. The client can override it with 622 local methods. */ 623 624 struct target_ops * 625 inf_ptrace_target (void) 626 { 627 struct target_ops *t = inf_child_target (); 628 629 t->to_attach = inf_ptrace_attach; 630 t->to_detach = inf_ptrace_detach; 631 t->to_resume = inf_ptrace_resume; 632 t->to_wait = inf_ptrace_wait; 633 t->to_files_info = inf_ptrace_files_info; 634 t->to_kill = inf_ptrace_kill; 635 t->to_create_inferior = inf_ptrace_create_inferior; 636 #ifdef PT_GET_PROCESS_STATE 637 t->to_follow_fork = inf_ptrace_follow_fork; 638 t->to_post_startup_inferior = inf_ptrace_post_startup_inferior; 639 t->to_post_attach = inf_ptrace_post_attach; 640 #endif 641 t->to_mourn_inferior = inf_ptrace_mourn_inferior; 642 t->to_thread_alive = inf_ptrace_thread_alive; 643 t->to_pid_to_str = inf_ptrace_pid_to_str; 644 t->to_stop = inf_ptrace_stop; 645 t->to_xfer_partial = inf_ptrace_xfer_partial; 646 647 return t; 648 } 649 650 651 /* Pointer to a function that returns the offset within the user area 652 where a particular register is stored. */ 653 static CORE_ADDR (*inf_ptrace_register_u_offset)(struct gdbarch *, int, int); 654 655 /* Fetch register REGNUM from the inferior. */ 656 657 static void 658 inf_ptrace_fetch_register (struct regcache *regcache, int regnum) 659 { 660 struct gdbarch *gdbarch = get_regcache_arch (regcache); 661 CORE_ADDR addr; 662 size_t size; 663 PTRACE_TYPE_RET *buf; 664 int pid, i; 665 666 /* This isn't really an address, but ptrace thinks of it as one. */ 667 addr = inf_ptrace_register_u_offset (gdbarch, regnum, 0); 668 if (addr == (CORE_ADDR)-1 669 || gdbarch_cannot_fetch_register (gdbarch, regnum)) 670 { 671 regcache_raw_supply (regcache, regnum, NULL); 672 return; 673 } 674 675 /* Cater for systems like GNU/Linux, that implement threads as 676 separate processes. */ 677 pid = ptid_get_lwp (inferior_ptid); 678 if (pid == 0) 679 pid = ptid_get_pid (inferior_ptid); 680 681 size = register_size (gdbarch, regnum); 682 gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); 683 buf = alloca (size); 684 685 /* Read the register contents from the inferior a chunk at a time. */ 686 for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) 687 { 688 errno = 0; 689 buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, 0); 690 if (errno != 0) 691 error (_("Couldn't read register %s (#%d): %s."), 692 gdbarch_register_name (gdbarch, regnum), 693 regnum, safe_strerror (errno)); 694 695 addr += sizeof (PTRACE_TYPE_RET); 696 } 697 regcache_raw_supply (regcache, regnum, buf); 698 } 699 700 /* Fetch register REGNUM from the inferior. If REGNUM is -1, do this 701 for all registers. */ 702 703 static void 704 inf_ptrace_fetch_registers (struct target_ops *ops, 705 struct regcache *regcache, int regnum) 706 { 707 if (regnum == -1) 708 for (regnum = 0; 709 regnum < gdbarch_num_regs (get_regcache_arch (regcache)); 710 regnum++) 711 inf_ptrace_fetch_register (regcache, regnum); 712 else 713 inf_ptrace_fetch_register (regcache, regnum); 714 } 715 716 /* Store register REGNUM into the inferior. */ 717 718 static void 719 inf_ptrace_store_register (const struct regcache *regcache, int regnum) 720 { 721 struct gdbarch *gdbarch = get_regcache_arch (regcache); 722 CORE_ADDR addr; 723 size_t size; 724 PTRACE_TYPE_RET *buf; 725 int pid, i; 726 727 /* This isn't really an address, but ptrace thinks of it as one. */ 728 addr = inf_ptrace_register_u_offset (gdbarch, regnum, 1); 729 if (addr == (CORE_ADDR)-1 730 || gdbarch_cannot_store_register (gdbarch, regnum)) 731 return; 732 733 /* Cater for systems like GNU/Linux, that implement threads as 734 separate processes. */ 735 pid = ptid_get_lwp (inferior_ptid); 736 if (pid == 0) 737 pid = ptid_get_pid (inferior_ptid); 738 739 size = register_size (gdbarch, regnum); 740 gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); 741 buf = alloca (size); 742 743 /* Write the register contents into the inferior a chunk at a time. */ 744 regcache_raw_collect (regcache, regnum, buf); 745 for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) 746 { 747 errno = 0; 748 ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, buf[i]); 749 if (errno != 0) 750 error (_("Couldn't write register %s (#%d): %s."), 751 gdbarch_register_name (gdbarch, regnum), 752 regnum, safe_strerror (errno)); 753 754 addr += sizeof (PTRACE_TYPE_RET); 755 } 756 } 757 758 /* Store register REGNUM back into the inferior. If REGNUM is -1, do 759 this for all registers. */ 760 761 static void 762 inf_ptrace_store_registers (struct target_ops *ops, 763 struct regcache *regcache, int regnum) 764 { 765 if (regnum == -1) 766 for (regnum = 0; 767 regnum < gdbarch_num_regs (get_regcache_arch (regcache)); 768 regnum++) 769 inf_ptrace_store_register (regcache, regnum); 770 else 771 inf_ptrace_store_register (regcache, regnum); 772 } 773 774 /* Create a "traditional" ptrace target. REGISTER_U_OFFSET should be 775 a function returning the offset within the user area where a 776 particular register is stored. */ 777 778 struct target_ops * 779 inf_ptrace_trad_target (CORE_ADDR (*register_u_offset) 780 (struct gdbarch *, int, int)) 781 { 782 struct target_ops *t = inf_ptrace_target(); 783 784 gdb_assert (register_u_offset); 785 inf_ptrace_register_u_offset = register_u_offset; 786 t->to_fetch_registers = inf_ptrace_fetch_registers; 787 t->to_store_registers = inf_ptrace_store_registers; 788 789 return t; 790 } 791