1/* Low level interface to ptrace, for the remote server for GDB. 2 Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004 3 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 59 Temple Place - Suite 330, 20 Boston, MA 02111-1307, USA. */ 21 22#include <sys/cdefs.h> 23__FBSDID("$FreeBSD$"); 24 25#include "server.h" 26#include "fbsd-low.h" 27 28#include <sys/wait.h> 29#include <sys/param.h> 30#include <sys/ptrace.h> 31#include <sys/user.h> 32#include <sys/ioctl.h> 33#include <dirent.h> 34#include <errno.h> 35#include <fcntl.h> 36#include <signal.h> 37#include <stdio.h> 38#include <stdlib.h> 39#include <string.h> 40#include <unistd.h> 41 42/* ``all_threads'' is keyed by the LWP ID - it should be the thread ID instead, 43 however. This requires changing the ID in place when we go from !using_threads 44 to using_threads, immediately. 45 46 ``all_processes'' is keyed by the process ID - which on Linux is (presently) 47 the same as the LWP ID. */ 48 49struct inferior_list all_processes; 50 51/* FIXME this is a bit of a hack, and could be removed. */ 52int stopping_threads; 53 54/* FIXME make into a target method? */ 55int using_threads; 56 57static void fbsd_resume_one_process (struct inferior_list_entry *entry, 58 int step, int signal); 59static void fbsd_resume (struct thread_resume *resume_info); 60static void stop_all_processes (void); 61static int fbsd_wait_for_event (struct thread_info *child); 62 63struct pending_signals 64{ 65 int signal; 66 struct pending_signals *prev; 67}; 68 69#define PTRACE_ARG3_TYPE caddr_t 70#define PTRACE_XFER_TYPE int 71 72int debug_threads = 0; 73 74#define pid_of(proc) ((proc)->head.id) 75 76/* FIXME: Delete eventually. */ 77#define inferior_pid (pid_of (get_thread_process (current_inferior))) 78 79/* This function should only be called if the process got a SIGTRAP. 80 The SIGTRAP could mean several things. 81 82 On i386, where decr_pc_after_break is non-zero: 83 If we were single-stepping this process using PT_STEP, 84 we will get only the one SIGTRAP (even if the instruction we 85 stepped over was a breakpoint). The value of $eip will be the 86 next instruction. 87 If we continue the process using PTRACE_CONT, we will get a 88 SIGTRAP when we hit a breakpoint. The value of $eip will be 89 the instruction after the breakpoint (i.e. needs to be 90 decremented). If we report the SIGTRAP to GDB, we must also 91 report the undecremented PC. If we cancel the SIGTRAP, we 92 must resume at the decremented PC. 93 94 (Presumably, not yet tested) On a non-decr_pc_after_break machine 95 with hardware or kernel single-step: 96 If we single-step over a breakpoint instruction, our PC will 97 point at the following instruction. If we continue and hit a 98 breakpoint instruction, our PC will point at the breakpoint 99 instruction. */ 100 101static CORE_ADDR 102get_stop_pc (void) 103{ 104 CORE_ADDR stop_pc = (*the_low_target.get_pc) (); 105 106 if (get_thread_process (current_inferior)->stepping) 107 return stop_pc; 108 else 109 return stop_pc - the_low_target.decr_pc_after_break; 110} 111 112static void * 113add_process (int pid) 114{ 115 struct process_info *process; 116 117 process = (struct process_info *) malloc (sizeof (*process)); 118 memset (process, 0, sizeof (*process)); 119 120 process->head.id = pid; 121 122 /* Default to tid == lwpid == pid. */ 123 process->tid = pid; 124 process->lwpid = pid; 125 126 add_inferior_to_list (&all_processes, &process->head); 127 128 return process; 129} 130 131/* Start an inferior process and returns its pid. 132 ALLARGS is a vector of program-name and args. */ 133 134static int 135fbsd_create_inferior (char *program, char **allargs) 136{ 137 void *new_process; 138 int pid; 139 140 pid = vfork (); 141 if (pid < 0) 142 perror_with_name ("vfork"); 143 144 if (pid == 0) 145 { 146 ptrace (PT_TRACE_ME, 0, 0, 0); 147 148 setpgid (0, 0); 149 150 execv (program, allargs); 151 152 fprintf (stderr, "Cannot exec %s: %s.\n", program, 153 strerror (errno)); 154 fflush (stderr); 155 _exit (0177); 156 } 157 158 new_process = add_process (pid); 159 add_thread (pid, new_process); 160 161 return pid; 162} 163 164/* Attach to an inferior process. */ 165 166void 167fbsd_attach_lwp (int pid, int tid) 168{ 169 struct process_info *new_process; 170 171 if (ptrace (PT_ATTACH, pid, 0, 0) != 0) 172 { 173 fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid, 174 strerror (errno), errno); 175 fflush (stderr); 176 177 /* If we fail to attach to an LWP, just return. */ 178 if (!using_threads) 179 _exit (0177); 180 return; 181 } 182 183 new_process = (struct process_info *) add_process (pid); 184 add_thread (tid, new_process); 185 186 /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH 187 brings it to a halt. We should ignore that SIGSTOP and resume the process 188 (unless this is the first process, in which case the flag will be cleared 189 in fbsd_attach). 190 191 On the other hand, if we are currently trying to stop all threads, we 192 should treat the new thread as if we had sent it a SIGSTOP. This works 193 because we are guaranteed that add_process added us to the end of the 194 list, and so the new thread has not yet reached wait_for_sigstop (but 195 will). */ 196 if (! stopping_threads) 197 new_process->stop_expected = 1; 198} 199 200int 201fbsd_attach (int pid) 202{ 203 struct process_info *process; 204 205 fbsd_attach_lwp (pid, pid); 206 207 /* Don't ignore the initial SIGSTOP if we just attached to this process. */ 208 process = (struct process_info *) find_inferior_id (&all_processes, pid); 209 process->stop_expected = 0; 210 211 return 0; 212} 213 214/* Kill the inferior process. Make us have no inferior. */ 215 216static void 217fbsd_kill_one_process (struct inferior_list_entry *entry) 218{ 219 struct thread_info *thread = (struct thread_info *) entry; 220 struct process_info *process = get_thread_process (thread); 221 int wstat; 222 223 do 224 { 225 ptrace (PT_KILL, pid_of (process), 0, 0); 226 227 /* Make sure it died. The loop is most likely unnecessary. */ 228 wstat = fbsd_wait_for_event (thread); 229 } while (WIFSTOPPED (wstat)); 230} 231 232static void 233fbsd_kill (void) 234{ 235 for_each_inferior (&all_threads, fbsd_kill_one_process); 236} 237 238static void 239fbsd_detach_one_process (struct inferior_list_entry *entry) 240{ 241 struct thread_info *thread = (struct thread_info *) entry; 242 struct process_info *process = get_thread_process (thread); 243 244 ptrace (PT_DETACH, pid_of (process), 0, 0); 245} 246 247static void 248fbsd_detach (void) 249{ 250 for_each_inferior (&all_threads, fbsd_detach_one_process); 251} 252 253/* Return nonzero if the given thread is still alive. */ 254static int 255fbsd_thread_alive (int tid) 256{ 257 if (find_inferior_id (&all_threads, tid) != NULL) 258 return 1; 259 else 260 return 0; 261} 262 263/* Return nonzero if this process stopped at a breakpoint which 264 no longer appears to be inserted. Also adjust the PC 265 appropriately to resume where the breakpoint used to be. */ 266static int 267check_removed_breakpoint (struct process_info *event_child) 268{ 269 CORE_ADDR stop_pc; 270 struct thread_info *saved_inferior; 271 272 if (event_child->pending_is_breakpoint == 0) 273 return 0; 274 275 if (debug_threads) 276 fprintf (stderr, "Checking for breakpoint.\n"); 277 278 saved_inferior = current_inferior; 279 current_inferior = get_process_thread (event_child); 280 281 stop_pc = get_stop_pc (); 282 283 /* If the PC has changed since we stopped, then we shouldn't do 284 anything. This happens if, for instance, GDB handled the 285 decr_pc_after_break subtraction itself. */ 286 if (stop_pc != event_child->pending_stop_pc) 287 { 288 if (debug_threads) 289 fprintf (stderr, "Ignoring, PC was changed.\n"); 290 291 event_child->pending_is_breakpoint = 0; 292 current_inferior = saved_inferior; 293 return 0; 294 } 295 296 /* If the breakpoint is still there, we will report hitting it. */ 297 if ((*the_low_target.breakpoint_at) (stop_pc)) 298 { 299 if (debug_threads) 300 fprintf (stderr, "Ignoring, breakpoint is still present.\n"); 301 current_inferior = saved_inferior; 302 return 0; 303 } 304 305 if (debug_threads) 306 fprintf (stderr, "Removed breakpoint.\n"); 307 308 /* For decr_pc_after_break targets, here is where we perform the 309 decrement. We go immediately from this function to resuming, 310 and can not safely call get_stop_pc () again. */ 311 if (the_low_target.set_pc != NULL) 312 (*the_low_target.set_pc) (stop_pc); 313 314 /* We consumed the pending SIGTRAP. */ 315 event_child->pending_is_breakpoint = 0; 316 event_child->status_pending_p = 0; 317 event_child->status_pending = 0; 318 319 current_inferior = saved_inferior; 320 return 1; 321} 322 323/* Return 1 if this process has an interesting status pending. This function 324 may silently resume an inferior process. */ 325static int 326status_pending_p (struct inferior_list_entry *entry, void *dummy) 327{ 328 struct process_info *process = (struct process_info *) entry; 329 330 if (process->status_pending_p) 331 if (check_removed_breakpoint (process)) 332 { 333 /* This thread was stopped at a breakpoint, and the breakpoint 334 is now gone. We were told to continue (or step...) all threads, 335 so GDB isn't trying to single-step past this breakpoint. 336 So instead of reporting the old SIGTRAP, pretend we got to 337 the breakpoint just after it was removed instead of just 338 before; resume the process. */ 339 fbsd_resume_one_process (&process->head, 0, 0); 340 return 0; 341 } 342 343 return process->status_pending_p; 344} 345 346static void 347fbsd_wait_for_process (struct process_info **childp, int *wstatp) 348{ 349 int ret; 350 int to_wait_for = -1; 351 352 if (*childp != NULL) 353 to_wait_for = (*childp)->lwpid; 354 355 while (1) 356 { 357 ret = waitpid (to_wait_for, wstatp, WNOHANG); 358 359 if (ret == -1) 360 { 361 if (errno != ECHILD) 362 perror_with_name ("waitpid"); 363 } 364 else if (ret > 0) 365 break; 366 367 usleep (1000); 368 } 369 370 if (debug_threads 371 && (!WIFSTOPPED (*wstatp) 372 || (WSTOPSIG (*wstatp) != 32 373 && WSTOPSIG (*wstatp) != 33))) 374 fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp); 375 376 if (to_wait_for == -1) 377 *childp = (struct process_info *) find_inferior_id (&all_processes, ret); 378 379 (*childp)->stopped = 1; 380 (*childp)->pending_is_breakpoint = 0; 381 382 if (debug_threads 383 && WIFSTOPPED (*wstatp)) 384 { 385 current_inferior = (struct thread_info *) 386 find_inferior_id (&all_threads, (*childp)->tid); 387 /* For testing only; i386_stop_pc prints out a diagnostic. */ 388 if (the_low_target.get_pc != NULL) 389 get_stop_pc (); 390 } 391} 392 393static int 394fbsd_wait_for_event (struct thread_info *child) 395{ 396 CORE_ADDR stop_pc; 397 struct process_info *event_child; 398 int wstat; 399 400 /* Check for a process with a pending status. */ 401 /* It is possible that the user changed the pending task's registers since 402 it stopped. We correctly handle the change of PC if we hit a breakpoint 403 (in check_removed_breakpoint); signals should be reported anyway. */ 404 if (child == NULL) 405 { 406 event_child = (struct process_info *) 407 find_inferior (&all_processes, status_pending_p, NULL); 408 if (debug_threads && event_child) 409 fprintf (stderr, "Got a pending child %d\n", event_child->lwpid); 410 } 411 else 412 { 413 event_child = get_thread_process (child); 414 if (event_child->status_pending_p 415 && check_removed_breakpoint (event_child)) 416 event_child = NULL; 417 } 418 419 if (event_child != NULL) 420 { 421 if (event_child->status_pending_p) 422 { 423 if (debug_threads) 424 fprintf (stderr, "Got an event from pending child %d (%04x)\n", 425 event_child->lwpid, event_child->status_pending); 426 wstat = event_child->status_pending; 427 event_child->status_pending_p = 0; 428 event_child->status_pending = 0; 429 current_inferior = get_process_thread (event_child); 430 return wstat; 431 } 432 } 433 434 /* We only enter this loop if no process has a pending wait status. Thus 435 any action taken in response to a wait status inside this loop is 436 responding as soon as we detect the status, not after any pending 437 events. */ 438 while (1) 439 { 440 if (child == NULL) 441 event_child = NULL; 442 else 443 event_child = get_thread_process (child); 444 445 fbsd_wait_for_process (&event_child, &wstat); 446 447 if (event_child == NULL) 448 error ("event from unknown child"); 449 450 current_inferior = (struct thread_info *) 451 find_inferior_id (&all_threads, event_child->tid); 452 453 if (using_threads) 454 { 455 /* Check for thread exit. */ 456 if (! WIFSTOPPED (wstat)) 457 { 458 if (debug_threads) 459 fprintf (stderr, "Thread %d (LWP %d) exiting\n", 460 event_child->tid, event_child->head.id); 461 462 /* If the last thread is exiting, just return. */ 463 if (all_threads.head == all_threads.tail) 464 return wstat; 465 466 dead_thread_notify (event_child->tid); 467 468 remove_inferior (&all_processes, &event_child->head); 469 free (event_child); 470 remove_thread (current_inferior); 471 current_inferior = (struct thread_info *) all_threads.head; 472 473 /* If we were waiting for this particular child to do something... 474 well, it did something. */ 475 if (child != NULL) 476 return wstat; 477 478 /* Wait for a more interesting event. */ 479 continue; 480 } 481 482 if (WIFSTOPPED (wstat) 483 && WSTOPSIG (wstat) == SIGSTOP 484 && event_child->stop_expected) 485 { 486 if (debug_threads) 487 fprintf (stderr, "Expected stop.\n"); 488 event_child->stop_expected = 0; 489 fbsd_resume_one_process (&event_child->head, 490 event_child->stepping, 0); 491 continue; 492 } 493 494 /* FIXME drow/2002-06-09: Get signal numbers from the inferior's 495 thread library? */ 496 if (WIFSTOPPED (wstat)) 497 { 498 if (debug_threads) 499 fprintf (stderr, "Ignored signal %d for %d (LWP %d).\n", 500 WSTOPSIG (wstat), event_child->tid, 501 event_child->head.id); 502 fbsd_resume_one_process (&event_child->head, 503 event_child->stepping, 504 WSTOPSIG (wstat)); 505 continue; 506 } 507 } 508 509 /* If this event was not handled above, and is not a SIGTRAP, report 510 it. */ 511 if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP) 512 return wstat; 513 514 /* If this target does not support breakpoints, we simply report the 515 SIGTRAP; it's of no concern to us. */ 516 if (the_low_target.get_pc == NULL) 517 return wstat; 518 519 stop_pc = get_stop_pc (); 520 521 /* bp_reinsert will only be set if we were single-stepping. 522 Notice that we will resume the process after hitting 523 a gdbserver breakpoint; single-stepping to/over one 524 is not supported (yet). */ 525 if (event_child->bp_reinsert != 0) 526 { 527 if (debug_threads) 528 fprintf (stderr, "Reinserted breakpoint.\n"); 529 reinsert_breakpoint (event_child->bp_reinsert); 530 event_child->bp_reinsert = 0; 531 532 /* Clear the single-stepping flag and SIGTRAP as we resume. */ 533 fbsd_resume_one_process (&event_child->head, 0, 0); 534 continue; 535 } 536 537 if (debug_threads) 538 fprintf (stderr, "Hit a (non-reinsert) breakpoint.\n"); 539 540 if (check_breakpoints (stop_pc) != 0) 541 { 542 /* We hit one of our own breakpoints. We mark it as a pending 543 breakpoint, so that check_removed_breakpoint () will do the PC 544 adjustment for us at the appropriate time. */ 545 event_child->pending_is_breakpoint = 1; 546 event_child->pending_stop_pc = stop_pc; 547 548 /* Now we need to put the breakpoint back. We continue in the event 549 loop instead of simply replacing the breakpoint right away, 550 in order to not lose signals sent to the thread that hit the 551 breakpoint. Unfortunately this increases the window where another 552 thread could sneak past the removed breakpoint. For the current 553 use of server-side breakpoints (thread creation) this is 554 acceptable; but it needs to be considered before this breakpoint 555 mechanism can be used in more general ways. For some breakpoints 556 it may be necessary to stop all other threads, but that should 557 be avoided where possible. 558 559 If breakpoint_reinsert_addr is NULL, that means that we can 560 use PT_STEP on this platform. Uninsert the breakpoint, 561 mark it for reinsertion, and single-step. 562 563 Otherwise, call the target function to figure out where we need 564 our temporary breakpoint, create it, and continue executing this 565 process. */ 566 if (the_low_target.breakpoint_reinsert_addr == NULL) 567 { 568 event_child->bp_reinsert = stop_pc; 569 uninsert_breakpoint (stop_pc); 570 fbsd_resume_one_process (&event_child->head, 1, 0); 571 } 572 else 573 { 574 reinsert_breakpoint_by_bp 575 (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ()); 576 fbsd_resume_one_process (&event_child->head, 0, 0); 577 } 578 579 continue; 580 } 581 582 /* If we were single-stepping, we definitely want to report the 583 SIGTRAP. The single-step operation has completed, so also 584 clear the stepping flag; in general this does not matter, 585 because the SIGTRAP will be reported to the client, which 586 will give us a new action for this thread, but clear it for 587 consistency anyway. It's safe to clear the stepping flag 588 because the only consumer of get_stop_pc () after this point 589 is check_removed_breakpoint, and pending_is_breakpoint is not 590 set. It might be wiser to use a step_completed flag instead. */ 591 if (event_child->stepping) 592 { 593 event_child->stepping = 0; 594 return wstat; 595 } 596 597 /* A SIGTRAP that we can't explain. It may have been a breakpoint. 598 Check if it is a breakpoint, and if so mark the process information 599 accordingly. This will handle both the necessary fiddling with the 600 PC on decr_pc_after_break targets and suppressing extra threads 601 hitting a breakpoint if two hit it at once and then GDB removes it 602 after the first is reported. Arguably it would be better to report 603 multiple threads hitting breakpoints simultaneously, but the current 604 remote protocol does not allow this. */ 605 if ((*the_low_target.breakpoint_at) (stop_pc)) 606 { 607 event_child->pending_is_breakpoint = 1; 608 event_child->pending_stop_pc = stop_pc; 609 } 610 611 return wstat; 612 } 613 614 /* NOTREACHED */ 615 return 0; 616} 617 618/* Wait for process, returns status. */ 619 620static unsigned char 621fbsd_wait (char *status) 622{ 623 int w; 624 struct thread_info *child = NULL; 625 626retry: 627 /* If we were only supposed to resume one thread, only wait for 628 that thread - if it's still alive. If it died, however - which 629 can happen if we're coming from the thread death case below - 630 then we need to make sure we restart the other threads. We could 631 pick a thread at random or restart all; restarting all is less 632 arbitrary. */ 633 if (cont_thread > 0) 634 { 635 child = (struct thread_info *) find_inferior_id (&all_threads, 636 cont_thread); 637 638 /* No stepping, no signal - unless one is pending already, of course. */ 639 if (child == NULL) 640 { 641 struct thread_resume resume_info; 642 resume_info.thread = -1; 643 resume_info.step = resume_info.sig = resume_info.leave_stopped = 0; 644 fbsd_resume (&resume_info); 645 } 646 } 647 648 enable_async_io (); 649 unblock_async_io (); 650 w = fbsd_wait_for_event (child); 651 stop_all_processes (); 652 disable_async_io (); 653 654 /* If we are waiting for a particular child, and it exited, 655 fbsd_wait_for_event will return its exit status. Similarly if 656 the last child exited. If this is not the last child, however, 657 do not report it as exited until there is a 'thread exited' response 658 available in the remote protocol. Instead, just wait for another event. 659 This should be safe, because if the thread crashed we will already 660 have reported the termination signal to GDB; that should stop any 661 in-progress stepping operations, etc. 662 663 Report the exit status of the last thread to exit. This matches 664 LinuxThreads' behavior. */ 665 666 if (all_threads.head == all_threads.tail) 667 { 668 if (WIFEXITED (w)) 669 { 670 fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w)); 671 *status = 'W'; 672 clear_inferiors (); 673 free (all_processes.head); 674 all_processes.head = all_processes.tail = NULL; 675 return ((unsigned char) WEXITSTATUS (w)); 676 } 677 else if (!WIFSTOPPED (w)) 678 { 679 fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w)); 680 *status = 'X'; 681 clear_inferiors (); 682 free (all_processes.head); 683 all_processes.head = all_processes.tail = NULL; 684 return ((unsigned char) WTERMSIG (w)); 685 } 686 } 687 else 688 { 689 if (!WIFSTOPPED (w)) 690 goto retry; 691 } 692 693 *status = 'T'; 694 return ((unsigned char) WSTOPSIG (w)); 695} 696 697static void 698send_sigstop (struct inferior_list_entry *entry) 699{ 700 struct process_info *process = (struct process_info *) entry; 701 702 if (process->stopped) 703 return; 704 705 /* If we already have a pending stop signal for this process, don't 706 send another. */ 707 if (process->stop_expected) 708 { 709 process->stop_expected = 0; 710 return; 711 } 712 713 if (debug_threads) 714 fprintf (stderr, "Sending sigstop to process %d\n", process->head.id); 715 716 kill (process->head.id, SIGSTOP); 717 process->sigstop_sent = 1; 718} 719 720static void 721wait_for_sigstop (struct inferior_list_entry *entry) 722{ 723 struct process_info *process = (struct process_info *) entry; 724 struct thread_info *saved_inferior, *thread; 725 int wstat, saved_tid; 726 727 if (process->stopped) 728 return; 729 730 saved_inferior = current_inferior; 731 saved_tid = ((struct inferior_list_entry *) saved_inferior)->id; 732 thread = (struct thread_info *) find_inferior_id (&all_threads, 733 process->tid); 734 wstat = fbsd_wait_for_event (thread); 735 736 /* If we stopped with a non-SIGSTOP signal, save it for later 737 and record the pending SIGSTOP. If the process exited, just 738 return. */ 739 if (WIFSTOPPED (wstat) 740 && WSTOPSIG (wstat) != SIGSTOP) 741 { 742 if (debug_threads) 743 fprintf (stderr, "Stopped with non-sigstop signal\n"); 744 process->status_pending_p = 1; 745 process->status_pending = wstat; 746 process->stop_expected = 1; 747 } 748 749 if (fbsd_thread_alive (saved_tid)) 750 current_inferior = saved_inferior; 751 else 752 { 753 if (debug_threads) 754 fprintf (stderr, "Previously current thread died.\n"); 755 756 /* Set a valid thread as current. */ 757 set_desired_inferior (0); 758 } 759} 760 761static void 762stop_all_processes (void) 763{ 764 stopping_threads = 1; 765 for_each_inferior (&all_processes, send_sigstop); 766 for_each_inferior (&all_processes, wait_for_sigstop); 767 stopping_threads = 0; 768} 769 770/* Resume execution of the inferior process. 771 If STEP is nonzero, single-step it. 772 If SIGNAL is nonzero, give it that signal. */ 773 774static void 775fbsd_resume_one_process (struct inferior_list_entry *entry, 776 int step, int signal) 777{ 778 struct process_info *process = (struct process_info *) entry; 779 struct thread_info *saved_inferior; 780 781 if (process->stopped == 0) 782 return; 783 784 /* If we have pending signals or status, and a new signal, enqueue the 785 signal. Also enqueue the signal if we are waiting to reinsert a 786 breakpoint; it will be picked up again below. */ 787 if (signal != 0 788 && (process->status_pending_p || process->pending_signals != NULL 789 || process->bp_reinsert != 0)) 790 { 791 struct pending_signals *p_sig; 792 p_sig = malloc (sizeof (*p_sig)); 793 p_sig->prev = process->pending_signals; 794 p_sig->signal = signal; 795 process->pending_signals = p_sig; 796 } 797 798 if (process->status_pending_p && !check_removed_breakpoint (process)) 799 return; 800 801 saved_inferior = current_inferior; 802 current_inferior = get_process_thread (process); 803 804 if (debug_threads) 805 fprintf (stderr, "Resuming process %d (%s, signal %d, stop %s)\n", inferior_pid, 806 step ? "step" : "continue", signal, 807 process->stop_expected ? "expected" : "not expected"); 808 809 /* This bit needs some thinking about. If we get a signal that 810 we must report while a single-step reinsert is still pending, 811 we often end up resuming the thread. It might be better to 812 (ew) allow a stack of pending events; then we could be sure that 813 the reinsert happened right away and not lose any signals. 814 815 Making this stack would also shrink the window in which breakpoints are 816 uninserted (see comment in fbsd_wait_for_process) but not enough for 817 complete correctness, so it won't solve that problem. It may be 818 worthwhile just to solve this one, however. */ 819 if (process->bp_reinsert != 0) 820 { 821 if (debug_threads) 822 fprintf (stderr, " pending reinsert at %08lx", (long)process->bp_reinsert); 823 if (step == 0) 824 fprintf (stderr, "BAD - reinserting but not stepping.\n"); 825 step = 1; 826 827 /* Postpone any pending signal. It was enqueued above. */ 828 signal = 0; 829 } 830 831 check_removed_breakpoint (process); 832 833 if (debug_threads && the_low_target.get_pc != NULL) 834 { 835 fprintf (stderr, " "); 836 (long) (*the_low_target.get_pc) (); 837 } 838 839 /* If we have pending signals, consume one unless we are trying to reinsert 840 a breakpoint. */ 841 if (process->pending_signals != NULL && process->bp_reinsert == 0) 842 { 843 struct pending_signals **p_sig; 844 845 p_sig = &process->pending_signals; 846 while ((*p_sig)->prev != NULL) 847 p_sig = &(*p_sig)->prev; 848 849 signal = (*p_sig)->signal; 850 free (*p_sig); 851 *p_sig = NULL; 852 } 853 854 regcache_invalidate_one ((struct inferior_list_entry *) 855 get_process_thread (process)); 856 errno = 0; 857 process->stopped = 0; 858 process->stepping = step; 859 ptrace (step ? PT_STEP : PT_CONTINUE, process->lwpid, (PTRACE_ARG3_TYPE) 1, signal); 860 861 current_inferior = saved_inferior; 862 if (errno) 863 perror_with_name ("ptrace"); 864} 865 866static struct thread_resume *resume_ptr; 867 868/* This function is called once per thread. We look up the thread 869 in RESUME_PTR, and mark the thread with a pointer to the appropriate 870 resume request. 871 872 This algorithm is O(threads * resume elements), but resume elements 873 is small (and will remain small at least until GDB supports thread 874 suspension). */ 875static void 876fbsd_set_resume_request (struct inferior_list_entry *entry) 877{ 878 struct process_info *process; 879 struct thread_info *thread; 880 int ndx; 881 882 thread = (struct thread_info *) entry; 883 process = get_thread_process (thread); 884 885 ndx = 0; 886 while (resume_ptr[ndx].thread != -1 && resume_ptr[ndx].thread != entry->id) 887 ndx++; 888 889 process->resume = &resume_ptr[ndx]; 890} 891 892/* This function is called once per thread. We check the thread's resume 893 request, which will tell us whether to resume, step, or leave the thread 894 stopped; and what signal, if any, it should be sent. For threads which 895 we aren't explicitly told otherwise, we preserve the stepping flag; this 896 is used for stepping over gdbserver-placed breakpoints. */ 897 898static void 899fbsd_continue_one_thread (struct inferior_list_entry *entry) 900{ 901 struct process_info *process; 902 struct thread_info *thread; 903 int step; 904 905 thread = (struct thread_info *) entry; 906 process = get_thread_process (thread); 907 908 if (process->resume->leave_stopped) 909 return; 910 911 if (process->resume->thread == -1) 912 step = process->stepping || process->resume->step; 913 else 914 step = process->resume->step; 915 916 fbsd_resume_one_process (&process->head, step, process->resume->sig); 917 918 process->resume = NULL; 919} 920 921/* This function is called once per thread. We check the thread's resume 922 request, which will tell us whether to resume, step, or leave the thread 923 stopped; and what signal, if any, it should be sent. We queue any needed 924 signals, since we won't actually resume. We already have a pending event 925 to report, so we don't need to preserve any step requests; they should 926 be re-issued if necessary. */ 927 928static void 929fbsd_queue_one_thread (struct inferior_list_entry *entry) 930{ 931 struct process_info *process; 932 struct thread_info *thread; 933 934 thread = (struct thread_info *) entry; 935 process = get_thread_process (thread); 936 937 if (process->resume->leave_stopped) 938 return; 939 940 /* If we have a new signal, enqueue the signal. */ 941 if (process->resume->sig != 0) 942 { 943 struct pending_signals *p_sig; 944 p_sig = malloc (sizeof (*p_sig)); 945 p_sig->prev = process->pending_signals; 946 p_sig->signal = process->resume->sig; 947 process->pending_signals = p_sig; 948 } 949 950 process->resume = NULL; 951} 952 953/* Set DUMMY if this process has an interesting status pending. */ 954static int 955resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p) 956{ 957 struct process_info *process = (struct process_info *) entry; 958 959 /* Processes which will not be resumed are not interesting, because 960 we might not wait for them next time through fbsd_wait. */ 961 if (process->resume->leave_stopped) 962 return 0; 963 964 /* If this thread has a removed breakpoint, we won't have any 965 events to report later, so check now. check_removed_breakpoint 966 may clear status_pending_p. We avoid calling check_removed_breakpoint 967 for any thread that we are not otherwise going to resume - this 968 lets us preserve stopped status when two threads hit a breakpoint. 969 GDB removes the breakpoint to single-step a particular thread 970 past it, then re-inserts it and resumes all threads. We want 971 to report the second thread without resuming it in the interim. */ 972 if (process->status_pending_p) 973 check_removed_breakpoint (process); 974 975 if (process->status_pending_p) 976 * (int *) flag_p = 1; 977 978 return 0; 979} 980 981static void 982fbsd_resume (struct thread_resume *resume_info) 983{ 984 int pending_flag; 985 986 /* Yes, the use of a global here is rather ugly. */ 987 resume_ptr = resume_info; 988 989 for_each_inferior (&all_threads, fbsd_set_resume_request); 990 991 /* If there is a thread which would otherwise be resumed, which 992 has a pending status, then don't resume any threads - we can just 993 report the pending status. Make sure to queue any signals 994 that would otherwise be sent. */ 995 pending_flag = 0; 996 find_inferior (&all_processes, resume_status_pending_p, &pending_flag); 997 998 if (debug_threads) 999 { 1000 if (pending_flag) 1001 fprintf (stderr, "Not resuming, pending status\n"); 1002 else 1003 fprintf (stderr, "Resuming, no pending status\n"); 1004 } 1005 1006 if (pending_flag) 1007 for_each_inferior (&all_threads, fbsd_queue_one_thread); 1008 else 1009 { 1010 block_async_io (); 1011 enable_async_io (); 1012 for_each_inferior (&all_threads, fbsd_continue_one_thread); 1013 } 1014} 1015 1016 1017static int 1018regsets_fetch_inferior_registers () 1019{ 1020 struct regset_info *regset; 1021 1022 regset = target_regsets; 1023 1024 while (regset->size >= 0) 1025 { 1026 void *buf; 1027 int res; 1028 1029 if (regset->size == 0) 1030 { 1031 regset ++; 1032 continue; 1033 } 1034 1035 buf = malloc (regset->size); 1036 res = ptrace (regset->get_request, inferior_pid, (PTRACE_ARG3_TYPE) buf, 0); 1037 if (res < 0) 1038 { 1039 char s[256]; 1040 sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d", 1041 inferior_pid); 1042 perror (s); 1043 } 1044 regset->store_function (buf); 1045 regset ++; 1046 } 1047 return 0; 1048} 1049 1050static int 1051regsets_store_inferior_registers () 1052{ 1053 struct regset_info *regset; 1054 1055 regset = target_regsets; 1056 1057 while (regset->size >= 0) 1058 { 1059 void *buf; 1060 int res; 1061 1062 if (regset->size == 0) 1063 { 1064 regset ++; 1065 continue; 1066 } 1067 1068 buf = malloc (regset->size); 1069 regset->fill_function (buf); 1070 res = ptrace (regset->set_request, inferior_pid, (PTRACE_ARG3_TYPE) buf, 0); 1071 if (res < 0) 1072 { 1073 perror ("Warning: ptrace(regsets_store_inferior_registers)"); 1074 } 1075 regset ++; 1076 free (buf); 1077 } 1078 return 0; 1079} 1080 1081void 1082fbsd_fetch_registers (int regno) 1083{ 1084 regsets_fetch_inferior_registers (); 1085} 1086 1087void 1088fbsd_store_registers (int regno) 1089{ 1090 regsets_store_inferior_registers (); 1091} 1092 1093 1094/* Copy LEN bytes from inferior's memory starting at MEMADDR 1095 to debugger memory starting at MYADDR. */ 1096 1097static int 1098fbsd_read_memory (CORE_ADDR memaddr, char *myaddr, int len) 1099{ 1100 register int i; 1101 /* Round starting address down to longword boundary. */ 1102 register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); 1103 /* Round ending address up; get number of longwords that makes. */ 1104 register int count 1105 = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) 1106 / sizeof (PTRACE_XFER_TYPE); 1107 /* Allocate buffer of that many longwords. */ 1108 register PTRACE_XFER_TYPE *buffer 1109 = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); 1110 1111 /* Read all the longwords */ 1112 for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) 1113 { 1114 errno = 0; 1115 buffer[i] = ptrace (PT_READ_D, inferior_pid, (PTRACE_ARG3_TYPE) (intptr_t)addr, 0); 1116 if (errno) 1117 return errno; 1118 } 1119 1120 /* Copy appropriate bytes out of the buffer. */ 1121 memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len); 1122 1123 return 0; 1124} 1125 1126/* Copy LEN bytes of data from debugger memory at MYADDR 1127 to inferior's memory at MEMADDR. 1128 On failure (cannot write the inferior) 1129 returns the value of errno. */ 1130 1131static int 1132fbsd_write_memory (CORE_ADDR memaddr, const char *myaddr, int len) 1133{ 1134 register int i; 1135 /* Round starting address down to longword boundary. */ 1136 register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); 1137 /* Round ending address up; get number of longwords that makes. */ 1138 register int count 1139 = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); 1140 /* Allocate buffer of that many longwords. */ 1141 register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); 1142 extern int errno; 1143 1144 if (debug_threads) 1145 { 1146 fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr); 1147 } 1148 1149 /* Fill start and end extra bytes of buffer with existing memory data. */ 1150 1151 buffer[0] = ptrace (PT_READ_D, inferior_pid, 1152 (PTRACE_ARG3_TYPE) (intptr_t)addr, 0); 1153 1154 if (count > 1) 1155 { 1156 buffer[count - 1] 1157 = ptrace (PT_READ_D, inferior_pid, 1158 (PTRACE_ARG3_TYPE) (intptr_t) (addr + (count - 1) 1159 * sizeof (PTRACE_XFER_TYPE)), 1160 0); 1161 } 1162 1163 /* Copy data to be written over corresponding part of buffer */ 1164 1165 memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len); 1166 1167 /* Write the entire buffer. */ 1168 1169 for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) 1170 { 1171 errno = 0; 1172 ptrace (PT_WRITE_D, inferior_pid, (PTRACE_ARG3_TYPE) (intptr_t)addr, buffer[i]); 1173 if (errno) 1174 return errno; 1175 } 1176 1177 return 0; 1178} 1179 1180static void 1181fbsd_look_up_symbols (void) 1182{ 1183#ifdef USE_THREAD_DB 1184 if (using_threads) 1185 return; 1186 1187 using_threads = thread_db_init (); 1188#endif 1189} 1190 1191static void 1192fbsd_send_signal (int signum) 1193{ 1194 extern int signal_pid; 1195 1196 if (cont_thread > 0) 1197 { 1198 struct process_info *process; 1199 1200 process = get_thread_process (current_inferior); 1201 kill (process->lwpid, signum); 1202 } 1203 else 1204 kill (signal_pid, signum); 1205} 1206 1207/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET 1208 to debugger memory starting at MYADDR. */ 1209 1210static int 1211fbsd_read_auxv (CORE_ADDR offset, char *myaddr, unsigned int len) 1212{ 1213 char filename[PATH_MAX]; 1214 int fd, n; 1215 1216 snprintf (filename, sizeof filename, "/proc/%d/auxv", inferior_pid); 1217 1218 fd = open (filename, O_RDONLY); 1219 if (fd < 0) 1220 return -1; 1221 1222 if (offset != (CORE_ADDR) 0 1223 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) 1224 n = -1; 1225 else 1226 n = read (fd, myaddr, len); 1227 1228 close (fd); 1229 1230 return n; 1231} 1232 1233 1234static struct target_ops fbsd_target_ops = { 1235 fbsd_create_inferior, 1236 fbsd_attach, 1237 fbsd_kill, 1238 fbsd_detach, 1239 fbsd_thread_alive, 1240 fbsd_resume, 1241 fbsd_wait, 1242 fbsd_fetch_registers, 1243 fbsd_store_registers, 1244 fbsd_read_memory, 1245 fbsd_write_memory, 1246 fbsd_look_up_symbols, 1247 fbsd_send_signal, 1248 fbsd_read_auxv, 1249}; 1250 1251static void 1252fbsd_init_signals () 1253{ 1254} 1255 1256void 1257initialize_low (void) 1258{ 1259 using_threads = 0; 1260 set_target_ops (&fbsd_target_ops); 1261 set_breakpoint_data (the_low_target.breakpoint, 1262 the_low_target.breakpoint_len); 1263 init_registers (); 1264 fbsd_init_signals (); 1265} 1266