1/* Low-level child interface to ptrace. 2 3 Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 4 1999, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 5 Free Software Foundation, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 21 22#include "defs.h" 23#include "command.h" 24#include "inferior.h" 25#include "inflow.h" 26#include "terminal.h" 27#include "gdbcore.h" 28#include "regcache.h" 29 30#include "gdb_assert.h" 31#include "gdb_string.h" 32#include "gdb_ptrace.h" 33#include "gdb_wait.h" 34#include <signal.h> 35 36#include "inf-ptrace.h" 37#include "inf-child.h" 38#include "gdbthread.h" 39 40 41 42#ifdef PT_GET_PROCESS_STATE 43 44static int 45inf_ptrace_follow_fork (struct target_ops *ops, int follow_child) 46{ 47 pid_t pid, fpid; 48 ptrace_state_t pe; 49 50 pid = ptid_get_pid (inferior_ptid); 51 52 if (ptrace (PT_GET_PROCESS_STATE, pid, 53 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 54 perror_with_name (("ptrace")); 55 56 gdb_assert (pe.pe_report_event == PTRACE_FORK); 57 fpid = pe.pe_other_pid; 58 59 if (follow_child) 60 { 61 struct inferior *parent_inf, *child_inf; 62 struct thread_info *tp; 63 64 parent_inf = find_inferior_pid (pid); 65 66 /* Add the child. */ 67 child_inf = add_inferior (fpid); 68 child_inf->attach_flag = parent_inf->attach_flag; 69 copy_terminal_info (child_inf, parent_inf); 70 child_inf->pspace = parent_inf->pspace; 71 child_inf->aspace = parent_inf->aspace; 72 73 /* Before detaching from the parent, remove all breakpoints from 74 it. */ 75 remove_breakpoints (); 76 77 if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1) 78 perror_with_name (("ptrace")); 79 80 /* Switch inferior_ptid out of the parent's way. */ 81 inferior_ptid = pid_to_ptid (fpid); 82 83 /* Delete the parent. */ 84 detach_inferior (pid); 85 86 add_thread_silent (inferior_ptid); 87 } 88 else 89 { 90 /* Breakpoints have already been detached from the child by 91 infrun.c. */ 92 93 if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1) 94 perror_with_name (("ptrace")); 95 } 96 97 return 0; 98} 99 100#endif /* PT_GET_PROCESS_STATE */ 101 102 103/* Prepare to be traced. */ 104 105static void 106inf_ptrace_me (void) 107{ 108 /* "Trace me, Dr. Memory!" */ 109 ptrace (PT_TRACE_ME, 0, (PTRACE_TYPE_ARG3)0, 0); 110} 111 112/* Start a new inferior Unix child process. EXEC_FILE is the file to 113 run, ALLARGS is a string containing the arguments to the program. 114 ENV is the environment vector to pass. If FROM_TTY is non-zero, be 115 chatty about it. */ 116 117static void 118inf_ptrace_create_inferior (struct target_ops *ops, 119 char *exec_file, char *allargs, char **env, 120 int from_tty) 121{ 122 int pid; 123 124 /* Do not change either targets above or the same target if already present. 125 The reason is the target stack is shared across multiple inferiors. */ 126 int ops_already_pushed = target_is_pushed (ops); 127 struct cleanup *back_to = NULL; 128 129 if (! ops_already_pushed) 130 { 131 /* Clear possible core file with its process_stratum. */ 132 push_target (ops); 133 back_to = make_cleanup_unpush_target (ops); 134 } 135 136 pid = fork_inferior (exec_file, allargs, env, inf_ptrace_me, NULL, 137 NULL, NULL); 138 139 if (! ops_already_pushed) 140 discard_cleanups (back_to); 141 142 /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h, and will 143 be 1 or 2 depending on whether we're starting without or with a 144 shell. */ 145 startup_inferior (START_INFERIOR_TRAPS_EXPECTED); 146 147 /* On some targets, there must be some explicit actions taken after 148 the inferior has been started up. */ 149 target_post_startup_inferior (pid_to_ptid (pid)); 150} 151 152#ifdef PT_GET_PROCESS_STATE 153 154static void 155inf_ptrace_post_startup_inferior (ptid_t pid) 156{ 157 ptrace_event_t pe; 158 159 /* Set the initial event mask. */ 160 memset (&pe, 0, sizeof pe); 161 pe.pe_set_event |= PTRACE_FORK; 162 if (ptrace (PT_SET_EVENT_MASK, ptid_get_pid (pid), 163 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 164 perror_with_name (("ptrace")); 165} 166 167#endif 168 169/* Clean up a rotting corpse of an inferior after it died. */ 170 171static void 172inf_ptrace_mourn_inferior (struct target_ops *ops) 173{ 174 int status; 175 176 /* Wait just one more time to collect the inferior's exit status. 177 Do not check whether this succeeds though, since we may be 178 dealing with a process that we attached to. Such a process will 179 only report its exit status to its original parent. */ 180 waitpid (ptid_get_pid (inferior_ptid), &status, 0); 181 182 generic_mourn_inferior (); 183 184 if (!have_inferiors ()) 185 unpush_target (ops); 186} 187 188/* Attach to the process specified by ARGS. If FROM_TTY is non-zero, 189 be chatty about it. */ 190 191static void 192inf_ptrace_attach (struct target_ops *ops, char *args, int from_tty) 193{ 194 char *exec_file; 195 pid_t pid; 196 struct inferior *inf; 197 198 /* Do not change either targets above or the same target if already present. 199 The reason is the target stack is shared across multiple inferiors. */ 200 int ops_already_pushed = target_is_pushed (ops); 201 struct cleanup *back_to = NULL; 202 203 pid = parse_pid_to_attach (args); 204 205 if (pid == getpid ()) /* Trying to masturbate? */ 206 error (_("I refuse to debug myself!")); 207 208 if (! ops_already_pushed) 209 { 210 /* target_pid_to_str already uses the target. Also clear possible core 211 file with its process_stratum. */ 212 push_target (ops); 213 back_to = make_cleanup_unpush_target (ops); 214 } 215 216 if (from_tty) 217 { 218 exec_file = get_exec_file (0); 219 220 if (exec_file) 221 printf_unfiltered (_("Attaching to program: %s, %s\n"), exec_file, 222 target_pid_to_str (pid_to_ptid (pid))); 223 else 224 printf_unfiltered (_("Attaching to %s\n"), 225 target_pid_to_str (pid_to_ptid (pid))); 226 227 gdb_flush (gdb_stdout); 228 } 229 230#ifdef PT_ATTACH 231 errno = 0; 232 ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3)0, 0); 233 if (errno != 0) 234 perror_with_name (("ptrace")); 235#else 236 error (_("This system does not support attaching to a process")); 237#endif 238 239 inf = current_inferior (); 240 inferior_appeared (inf, pid); 241 inf->attach_flag = 1; 242 inferior_ptid = pid_to_ptid (pid); 243 244 /* Always add a main thread. If some target extends the ptrace 245 target, it should decorate the ptid later with more info. */ 246 add_thread_silent (inferior_ptid); 247 248 if (! ops_already_pushed) 249 discard_cleanups (back_to); 250} 251 252#ifdef PT_GET_PROCESS_STATE 253 254void 255inf_ptrace_post_attach (int pid) 256{ 257 ptrace_event_t pe; 258 259 /* Set the initial event mask. */ 260 memset (&pe, 0, sizeof pe); 261 pe.pe_set_event |= PTRACE_FORK; 262 if (ptrace (PT_SET_EVENT_MASK, pid, 263 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 264 perror_with_name (("ptrace")); 265} 266 267#endif 268 269/* Detach from the inferior, optionally passing it the signal 270 specified by ARGS. If FROM_TTY is non-zero, be chatty about it. */ 271 272static void 273inf_ptrace_detach (struct target_ops *ops, char *args, int from_tty) 274{ 275 pid_t pid = ptid_get_pid (inferior_ptid); 276 int sig = 0; 277 278 if (from_tty) 279 { 280 char *exec_file = get_exec_file (0); 281 if (exec_file == 0) 282 exec_file = ""; 283 printf_unfiltered (_("Detaching from program: %s, %s\n"), exec_file, 284 target_pid_to_str (pid_to_ptid (pid))); 285 gdb_flush (gdb_stdout); 286 } 287 if (args) 288 sig = atoi (args); 289 290#ifdef PT_DETACH 291 /* We'd better not have left any breakpoints in the program or it'll 292 die when it hits one. Also note that this may only work if we 293 previously attached to the inferior. It *might* work if we 294 started the process ourselves. */ 295 errno = 0; 296 ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, sig); 297 if (errno != 0) 298 perror_with_name (("ptrace")); 299#else 300 error (_("This system does not support detaching from a process")); 301#endif 302 303 inferior_ptid = null_ptid; 304 detach_inferior (pid); 305 306 if (!have_inferiors ()) 307 unpush_target (ops); 308} 309 310/* Kill the inferior. */ 311 312static void 313inf_ptrace_kill (struct target_ops *ops) 314{ 315 pid_t pid = ptid_get_pid (inferior_ptid); 316 int status; 317 318 if (pid == 0) 319 return; 320 321 ptrace (PT_KILL, pid, (PTRACE_TYPE_ARG3)0, 0); 322 waitpid (pid, &status, 0); 323 324 target_mourn_inferior (); 325} 326 327/* Stop the inferior. */ 328 329static void 330inf_ptrace_stop (ptid_t ptid) 331{ 332 /* Send a SIGINT to the process group. This acts just like the user 333 typed a ^C on the controlling terminal. Note that using a 334 negative process number in kill() is a System V-ism. The proper 335 BSD interface is killpg(). However, all modern BSDs support the 336 System V interface too. */ 337 kill (-inferior_process_group (), SIGINT); 338} 339 340/* Resume execution of thread PTID, or all threads if PTID is -1. If 341 STEP is nonzero, single-step it. If SIGNAL is nonzero, give it 342 that signal. */ 343 344static void 345inf_ptrace_resume (struct target_ops *ops, 346 ptid_t ptid, int step, enum target_signal signal) 347{ 348 pid_t pid = ptid_get_pid (ptid); 349 int request, sig; 350 351 if (pid == -1) 352 /* Resume all threads. Traditionally ptrace() only supports 353 single-threaded processes, so simply resume the inferior. */ 354 pid = ptid_get_pid (inferior_ptid); 355 356 if (catch_syscall_enabled () > 0) 357 request = PT_SYSCALL; 358 else 359 request = PT_CONTINUE; 360 361 if (step) 362 { 363 /* If this system does not support PT_STEP, a higher level 364 function will have called single_step() to transmute the step 365 request into a continue request (by setting breakpoints on 366 all possible successor instructions), so we don't have to 367 worry about that here. */ 368 request = PT_STEP; 369#ifdef __NetBSD__ 370 sig = ptid_get_lwp(ptid); 371#else 372 sig = 0; 373#endif 374 } else 375 sig = target_signal_to_host (signal); 376 377 /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from 378 where it was. If GDB wanted it to start some other way, we have 379 already written a new program counter value to the child. */ 380 errno = 0; 381 ptrace (request, pid, (PTRACE_TYPE_ARG3)1, sig); 382 if (errno != 0) 383 perror_with_name (("ptrace")); 384} 385 386/* Wait for the child specified by PTID to do something. Return the 387 process ID of the child, or MINUS_ONE_PTID in case of error; store 388 the status in *OURSTATUS. */ 389 390static ptid_t 391inf_ptrace_wait (struct target_ops *ops, 392 ptid_t ptid, struct target_waitstatus *ourstatus, int options) 393{ 394 pid_t pid; 395 int status, save_errno; 396 397 do 398 { 399 set_sigint_trap (); 400 401 do 402 { 403 pid = waitpid (ptid_get_pid (ptid), &status, 0); 404 save_errno = errno; 405 } 406 while (pid == -1 && errno == EINTR); 407 408 clear_sigint_trap (); 409 410 if (pid == -1) 411 { 412 fprintf_unfiltered (gdb_stderr, 413 _("Child process unexpectedly missing: %s.\n"), 414 safe_strerror (save_errno)); 415 416 /* Claim it exited with unknown signal. */ 417 ourstatus->kind = TARGET_WAITKIND_SIGNALLED; 418 ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; 419 return inferior_ptid; 420 } 421 422 /* Ignore terminated detached child processes. */ 423 if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid)) 424 pid = -1; 425 } 426 while (pid == -1); 427 428#ifdef PT_GET_PROCESS_STATE 429 if (WIFSTOPPED (status)) 430 { 431 ptrace_state_t pe; 432 pid_t fpid; 433 434 if (ptrace (PT_GET_PROCESS_STATE, pid, 435 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 436 perror_with_name (("ptrace")); 437 438 switch (pe.pe_report_event) 439 { 440 case PTRACE_FORK: 441 ourstatus->kind = TARGET_WAITKIND_FORKED; 442 ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid); 443 444 /* Make sure the other end of the fork is stopped too. */ 445 fpid = waitpid (pe.pe_other_pid, &status, 0); 446 if (fpid == -1) 447 perror_with_name (("waitpid")); 448 449 if (ptrace (PT_GET_PROCESS_STATE, fpid, 450 (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) 451 perror_with_name (("ptrace")); 452 453 gdb_assert (pe.pe_report_event == PTRACE_FORK); 454 gdb_assert (pe.pe_other_pid == pid); 455 if (fpid == ptid_get_pid (inferior_ptid)) 456 { 457 ourstatus->value.related_pid = pid_to_ptid (pe.pe_other_pid); 458 return pid_to_ptid (fpid); 459 } 460 461 return pid_to_ptid (pid); 462 } 463 } 464#endif 465 466 store_waitstatus (ourstatus, status); 467 return pid_to_ptid (pid); 468} 469 470/* Attempt a transfer all LEN bytes starting at OFFSET between the 471 inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer. 472 Return the number of bytes actually transferred. */ 473 474static LONGEST 475inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object, 476 const char *annex, gdb_byte *readbuf, 477 const gdb_byte *writebuf, 478 ULONGEST offset, LONGEST len) 479{ 480 pid_t pid = ptid_get_pid (inferior_ptid); 481 482 switch (object) 483 { 484 case TARGET_OBJECT_MEMORY: 485#ifdef PT_IO 486 /* OpenBSD 3.1, NetBSD 1.6 and FreeBSD 5.0 have a new PT_IO 487 request that promises to be much more efficient in reading 488 and writing data in the traced process's address space. */ 489 { 490 struct ptrace_io_desc piod; 491 492 /* NOTE: We assume that there are no distinct address spaces 493 for instruction and data. However, on OpenBSD 3.9 and 494 later, PIOD_WRITE_D doesn't allow changing memory that's 495 mapped read-only. Since most code segments will be 496 read-only, using PIOD_WRITE_D will prevent us from 497 inserting breakpoints, so we use PIOD_WRITE_I instead. */ 498 piod.piod_op = writebuf ? PIOD_WRITE_I : PIOD_READ_D; 499 piod.piod_addr = writebuf ? (void *) writebuf : readbuf; 500 piod.piod_offs = (void *) (long) offset; 501 piod.piod_len = len; 502 503 errno = 0; 504 if (ptrace (PT_IO, pid, (caddr_t)&piod, 0) == 0) 505 /* Return the actual number of bytes read or written. */ 506 return piod.piod_len; 507 /* If the PT_IO request is somehow not supported, fallback on 508 using PT_WRITE_D/PT_READ_D. Otherwise we will return zero 509 to indicate failure. */ 510 if (errno != EINVAL) 511 return 0; 512 } 513#endif 514 { 515 union 516 { 517 PTRACE_TYPE_RET word; 518 gdb_byte byte[sizeof (PTRACE_TYPE_RET)]; 519 } buffer; 520 ULONGEST rounded_offset; 521 LONGEST partial_len; 522 523 /* Round the start offset down to the next long word 524 boundary. */ 525 rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET); 526 527 /* Since ptrace will transfer a single word starting at that 528 rounded_offset the partial_len needs to be adjusted down to 529 that (remember this function only does a single transfer). 530 Should the required length be even less, adjust it down 531 again. */ 532 partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset; 533 if (partial_len > len) 534 partial_len = len; 535 536 if (writebuf) 537 { 538 /* If OFFSET:PARTIAL_LEN is smaller than 539 ROUNDED_OFFSET:WORDSIZE then a read/modify write will 540 be needed. Read in the entire word. */ 541 if (rounded_offset < offset 542 || (offset + partial_len 543 < rounded_offset + sizeof (PTRACE_TYPE_RET))) 544 /* Need part of initial word -- fetch it. */ 545 buffer.word = ptrace (PT_READ_I, pid, 546 (PTRACE_TYPE_ARG3)(uintptr_t) 547 rounded_offset, 0); 548 549 /* Copy data to be written over corresponding part of 550 buffer. */ 551 memcpy (buffer.byte + (offset - rounded_offset), 552 writebuf, partial_len); 553 554 errno = 0; 555 ptrace (PT_WRITE_D, pid, 556 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 557 buffer.word); 558 if (errno) 559 { 560 /* Using the appropriate one (I or D) is necessary for 561 Gould NP1, at least. */ 562 errno = 0; 563 ptrace (PT_WRITE_I, pid, 564 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 565 buffer.word); 566 if (errno) 567 return 0; 568 } 569 } 570 571 if (readbuf) 572 { 573 errno = 0; 574 buffer.word = ptrace (PT_READ_I, pid, 575 (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, 576 0); 577 if (errno) 578 return 0; 579 /* Copy appropriate bytes out of the buffer. */ 580 memcpy (readbuf, buffer.byte + (offset - rounded_offset), 581 partial_len); 582 } 583 584 return partial_len; 585 } 586 587 case TARGET_OBJECT_UNWIND_TABLE: 588 return -1; 589 590 case TARGET_OBJECT_AUXV: 591 return -1; 592 593 case TARGET_OBJECT_WCOOKIE: 594 return -1; 595 596 default: 597 return -1; 598 } 599} 600 601/* Return non-zero if the thread specified by PTID is alive. */ 602 603static int 604inf_ptrace_thread_alive (struct target_ops *ops, ptid_t ptid) 605{ 606 /* ??? Is kill the right way to do this? */ 607 return (kill (ptid_get_pid (ptid), 0) != -1); 608} 609 610/* Print status information about what we're accessing. */ 611 612static void 613inf_ptrace_files_info (struct target_ops *ignore) 614{ 615 struct inferior *inf = current_inferior (); 616 617 printf_filtered (_("\tUsing the running image of %s %s.\n"), 618 inf->attach_flag ? "attached" : "child", 619 target_pid_to_str (inferior_ptid)); 620} 621 622static char * 623inf_ptrace_pid_to_str (struct target_ops *ops, ptid_t ptid) 624{ 625 return normal_pid_to_str (ptid); 626} 627 628/* Create a prototype ptrace target. The client can override it with 629 local methods. */ 630 631struct target_ops * 632inf_ptrace_target (void) 633{ 634 struct target_ops *t = inf_child_target (); 635 636 t->to_attach = inf_ptrace_attach; 637 t->to_detach = inf_ptrace_detach; 638 t->to_resume = inf_ptrace_resume; 639 t->to_wait = inf_ptrace_wait; 640 t->to_files_info = inf_ptrace_files_info; 641 t->to_kill = inf_ptrace_kill; 642 t->to_create_inferior = inf_ptrace_create_inferior; 643#ifdef PT_GET_PROCESS_STATE 644 t->to_follow_fork = inf_ptrace_follow_fork; 645 t->to_post_startup_inferior = inf_ptrace_post_startup_inferior; 646 t->to_post_attach = inf_ptrace_post_attach; 647#endif 648 t->to_mourn_inferior = inf_ptrace_mourn_inferior; 649 t->to_thread_alive = inf_ptrace_thread_alive; 650 t->to_pid_to_str = inf_ptrace_pid_to_str; 651 t->to_stop = inf_ptrace_stop; 652 t->to_xfer_partial = inf_ptrace_xfer_partial; 653 654 return t; 655} 656 657 658/* Pointer to a function that returns the offset within the user area 659 where a particular register is stored. */ 660static CORE_ADDR (*inf_ptrace_register_u_offset)(struct gdbarch *, int, int); 661 662/* Fetch register REGNUM from the inferior. */ 663 664static void 665inf_ptrace_fetch_register (struct regcache *regcache, int regnum) 666{ 667 struct gdbarch *gdbarch = get_regcache_arch (regcache); 668 CORE_ADDR addr; 669 size_t size; 670 PTRACE_TYPE_RET *buf; 671 int pid, i; 672 673 /* This isn't really an address, but ptrace thinks of it as one. */ 674 addr = inf_ptrace_register_u_offset (gdbarch, regnum, 0); 675 if (addr == (CORE_ADDR)-1 676 || gdbarch_cannot_fetch_register (gdbarch, regnum)) 677 { 678 regcache_raw_supply (regcache, regnum, NULL); 679 return; 680 } 681 682 /* Cater for systems like GNU/Linux, that implement threads as 683 separate processes. */ 684 pid = ptid_get_lwp (inferior_ptid); 685 if (pid == 0) 686 pid = ptid_get_pid (inferior_ptid); 687 688 size = register_size (gdbarch, regnum); 689 gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); 690 buf = alloca (size); 691 692 /* Read the register contents from the inferior a chunk at a time. */ 693 for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) 694 { 695 errno = 0; 696 buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, 0); 697 if (errno != 0) 698 error (_("Couldn't read register %s (#%d): %s."), 699 gdbarch_register_name (gdbarch, regnum), 700 regnum, safe_strerror (errno)); 701 702 addr += sizeof (PTRACE_TYPE_RET); 703 } 704 regcache_raw_supply (regcache, regnum, buf); 705} 706 707/* Fetch register REGNUM from the inferior. If REGNUM is -1, do this 708 for all registers. */ 709 710static void 711inf_ptrace_fetch_registers (struct target_ops *ops, 712 struct regcache *regcache, int regnum) 713{ 714 if (regnum == -1) 715 for (regnum = 0; 716 regnum < gdbarch_num_regs (get_regcache_arch (regcache)); 717 regnum++) 718 inf_ptrace_fetch_register (regcache, regnum); 719 else 720 inf_ptrace_fetch_register (regcache, regnum); 721} 722 723/* Store register REGNUM into the inferior. */ 724 725static void 726inf_ptrace_store_register (const struct regcache *regcache, int regnum) 727{ 728 struct gdbarch *gdbarch = get_regcache_arch (regcache); 729 CORE_ADDR addr; 730 size_t size; 731 PTRACE_TYPE_RET *buf; 732 int pid, i; 733 734 /* This isn't really an address, but ptrace thinks of it as one. */ 735 addr = inf_ptrace_register_u_offset (gdbarch, regnum, 1); 736 if (addr == (CORE_ADDR)-1 737 || gdbarch_cannot_store_register (gdbarch, regnum)) 738 return; 739 740 /* Cater for systems like GNU/Linux, that implement threads as 741 separate processes. */ 742 pid = ptid_get_lwp (inferior_ptid); 743 if (pid == 0) 744 pid = ptid_get_pid (inferior_ptid); 745 746 size = register_size (gdbarch, regnum); 747 gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); 748 buf = alloca (size); 749 750 /* Write the register contents into the inferior a chunk at a time. */ 751 regcache_raw_collect (regcache, regnum, buf); 752 for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) 753 { 754 errno = 0; 755 ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, buf[i]); 756 if (errno != 0) 757 error (_("Couldn't write register %s (#%d): %s."), 758 gdbarch_register_name (gdbarch, regnum), 759 regnum, safe_strerror (errno)); 760 761 addr += sizeof (PTRACE_TYPE_RET); 762 } 763} 764 765/* Store register REGNUM back into the inferior. If REGNUM is -1, do 766 this for all registers. */ 767 768static void 769inf_ptrace_store_registers (struct target_ops *ops, 770 struct regcache *regcache, int regnum) 771{ 772 if (regnum == -1) 773 for (regnum = 0; 774 regnum < gdbarch_num_regs (get_regcache_arch (regcache)); 775 regnum++) 776 inf_ptrace_store_register (regcache, regnum); 777 else 778 inf_ptrace_store_register (regcache, regnum); 779} 780 781/* Create a "traditional" ptrace target. REGISTER_U_OFFSET should be 782 a function returning the offset within the user area where a 783 particular register is stored. */ 784 785struct target_ops * 786inf_ptrace_trad_target (CORE_ADDR (*register_u_offset) 787 (struct gdbarch *, int, int)) 788{ 789 struct target_ops *t = inf_ptrace_target(); 790 791 gdb_assert (register_u_offset); 792 inf_ptrace_register_u_offset = register_u_offset; 793 t->to_fetch_registers = inf_ptrace_fetch_registers; 794 t->to_store_registers = inf_ptrace_store_registers; 795 796 return t; 797} 798