| 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 |
| 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 2 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, write to the Free Software |
| 21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| 22 | Boston, MA 02110-1301, USA. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "command.h" |
| 26 | #include "inferior.h" |
| 27 | #include "inflow.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "regcache.h" |
| 30 | |
| 31 | #include "gdb_stdint.h" |
| 32 | #include "gdb_assert.h" |
| 33 | #include "gdb_string.h" |
| 34 | #include "gdb_ptrace.h" |
| 35 | #include "gdb_wait.h" |
| 36 | #include <signal.h> |
| 37 | |
| 38 | #include "inf-child.h" |
| 39 | |
| 40 | /* HACK: Save the ptrace ops returned by inf_ptrace_target. */ |
| 41 | static struct target_ops *ptrace_ops_hack; |
| 42 | \f |
| 43 | |
| 44 | #ifdef PT_GET_PROCESS_STATE |
| 45 | |
| 46 | static int |
| 47 | inf_ptrace_follow_fork (struct target_ops *ops, int follow_child) |
| 48 | { |
| 49 | pid_t pid, fpid; |
| 50 | ptrace_state_t pe; |
| 51 | |
| 52 | /* FIXME: kettenis/20050720: This stuff should really be passed as |
| 53 | an argument by our caller. */ |
| 54 | { |
| 55 | ptid_t ptid; |
| 56 | struct target_waitstatus status; |
| 57 | |
| 58 | get_last_target_status (&ptid, &status); |
| 59 | gdb_assert (status.kind == TARGET_WAITKIND_FORKED); |
| 60 | |
| 61 | pid = ptid_get_pid (ptid); |
| 62 | } |
| 63 | |
| 64 | if (ptrace (PT_GET_PROCESS_STATE, pid, |
| 65 | (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) |
| 66 | perror_with_name (("ptrace")); |
| 67 | |
| 68 | gdb_assert (pe.pe_report_event == PTRACE_FORK); |
| 69 | fpid = pe.pe_other_pid; |
| 70 | |
| 71 | if (follow_child) |
| 72 | { |
| 73 | inferior_ptid = pid_to_ptid (fpid); |
| 74 | detach_breakpoints (pid); |
| 75 | |
| 76 | /* Reset breakpoints in the child as appropriate. */ |
| 77 | follow_inferior_reset_breakpoints (); |
| 78 | |
| 79 | if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1) |
| 80 | perror_with_name (("ptrace")); |
| 81 | } |
| 82 | else |
| 83 | { |
| 84 | inferior_ptid = pid_to_ptid (pid); |
| 85 | detach_breakpoints (fpid); |
| 86 | |
| 87 | if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1) |
| 88 | perror_with_name (("ptrace")); |
| 89 | } |
| 90 | |
| 91 | return 0; |
| 92 | } |
| 93 | |
| 94 | #endif /* PT_GET_PROCESS_STATE */ |
| 95 | \f |
| 96 | |
| 97 | /* Prepare to be traced. */ |
| 98 | |
| 99 | static void |
| 100 | inf_ptrace_me (void) |
| 101 | { |
| 102 | /* "Trace me, Dr. Memory!" */ |
| 103 | ptrace (PT_TRACE_ME, 0, (PTRACE_TYPE_ARG3)0, 0); |
| 104 | } |
| 105 | |
| 106 | /* Start tracing PID. */ |
| 107 | |
| 108 | static void |
| 109 | inf_ptrace_him (int pid) |
| 110 | { |
| 111 | push_target (ptrace_ops_hack); |
| 112 | |
| 113 | /* On some targets, there must be some explicit synchronization |
| 114 | between the parent and child processes after the debugger |
| 115 | forks, and before the child execs the debuggee program. This |
| 116 | call basically gives permission for the child to exec. */ |
| 117 | |
| 118 | target_acknowledge_created_inferior (pid); |
| 119 | |
| 120 | /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h, and will |
| 121 | be 1 or 2 depending on whether we're starting without or with a |
| 122 | shell. */ |
| 123 | startup_inferior (START_INFERIOR_TRAPS_EXPECTED); |
| 124 | |
| 125 | /* On some targets, there must be some explicit actions taken after |
| 126 | the inferior has been started up. */ |
| 127 | target_post_startup_inferior (pid_to_ptid (pid)); |
| 128 | } |
| 129 | |
| 130 | /* Start a new inferior Unix child process. EXEC_FILE is the file to |
| 131 | run, ALLARGS is a string containing the arguments to the program. |
| 132 | ENV is the environment vector to pass. If FROM_TTY is non-zero, be |
| 133 | chatty about it. */ |
| 134 | |
| 135 | static void |
| 136 | inf_ptrace_create_inferior (char *exec_file, char *allargs, char **env, |
| 137 | int from_tty) |
| 138 | { |
| 139 | fork_inferior (exec_file, allargs, env, inf_ptrace_me, inf_ptrace_him, |
| 140 | NULL, NULL); |
| 141 | } |
| 142 | |
| 143 | #ifdef PT_GET_PROCESS_STATE |
| 144 | |
| 145 | static void |
| 146 | inf_ptrace_post_startup_inferior (ptid_t pid) |
| 147 | { |
| 148 | ptrace_event_t pe; |
| 149 | |
| 150 | /* Set the initial event mask. */ |
| 151 | memset (&pe, 0, sizeof pe); |
| 152 | pe.pe_set_event |= PTRACE_FORK; |
| 153 | if (ptrace (PT_SET_EVENT_MASK, ptid_get_pid (pid), |
| 154 | (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) |
| 155 | perror_with_name (("ptrace")); |
| 156 | } |
| 157 | |
| 158 | #endif |
| 159 | |
| 160 | /* Clean up a rotting corpse of an inferior after it died. */ |
| 161 | |
| 162 | static void |
| 163 | inf_ptrace_mourn_inferior (void) |
| 164 | { |
| 165 | int status; |
| 166 | |
| 167 | /* Wait just one more time to collect the inferior's exit status. |
| 168 | Do not check whether this succeeds though, since we may be |
| 169 | dealing with a process that we attached to. Such a process will |
| 170 | only report its exit status to its original parent. */ |
| 171 | waitpid (ptid_get_pid (inferior_ptid), &status, 0); |
| 172 | |
| 173 | unpush_target (ptrace_ops_hack); |
| 174 | generic_mourn_inferior (); |
| 175 | } |
| 176 | |
| 177 | /* Attach to the process specified by ARGS. If FROM_TTY is non-zero, |
| 178 | be chatty about it. */ |
| 179 | |
| 180 | static void |
| 181 | inf_ptrace_attach (char *args, int from_tty) |
| 182 | { |
| 183 | char *exec_file; |
| 184 | pid_t pid; |
| 185 | char *dummy; |
| 186 | |
| 187 | if (!args) |
| 188 | error_no_arg (_("process-id to attach")); |
| 189 | |
| 190 | dummy = args; |
| 191 | pid = strtol (args, &dummy, 0); |
| 192 | /* Some targets don't set errno on errors, grrr! */ |
| 193 | if (pid == 0 && args == dummy) |
| 194 | error (_("Illegal process-id: %s."), args); |
| 195 | |
| 196 | if (pid == getpid ()) /* Trying to masturbate? */ |
| 197 | error (_("I refuse to debug myself!")); |
| 198 | |
| 199 | if (from_tty) |
| 200 | { |
| 201 | exec_file = get_exec_file (0); |
| 202 | |
| 203 | if (exec_file) |
| 204 | printf_unfiltered (_("Attaching to program: %s, %s\n"), exec_file, |
| 205 | target_pid_to_str (pid_to_ptid (pid))); |
| 206 | else |
| 207 | printf_unfiltered (_("Attaching to %s\n"), |
| 208 | target_pid_to_str (pid_to_ptid (pid))); |
| 209 | |
| 210 | gdb_flush (gdb_stdout); |
| 211 | } |
| 212 | |
| 213 | #ifdef PT_ATTACH |
| 214 | errno = 0; |
| 215 | ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3)0, 0); |
| 216 | if (errno != 0) |
| 217 | perror_with_name (("ptrace")); |
| 218 | attach_flag = 1; |
| 219 | #else |
| 220 | error (_("This system does not support attaching to a process")); |
| 221 | #endif |
| 222 | |
| 223 | inferior_ptid = pid_to_ptid (pid); |
| 224 | push_target (ptrace_ops_hack); |
| 225 | } |
| 226 | |
| 227 | #ifdef PT_GET_PROCESS_STATE |
| 228 | |
| 229 | void |
| 230 | inf_ptrace_post_attach (int pid) |
| 231 | { |
| 232 | ptrace_event_t pe; |
| 233 | |
| 234 | /* Set the initial event mask. */ |
| 235 | memset (&pe, 0, sizeof pe); |
| 236 | pe.pe_set_event |= PTRACE_FORK; |
| 237 | if (ptrace (PT_SET_EVENT_MASK, pid, |
| 238 | (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) |
| 239 | perror_with_name (("ptrace")); |
| 240 | } |
| 241 | |
| 242 | #endif |
| 243 | |
| 244 | /* Detach from the inferior, optionally passing it the signal |
| 245 | specified by ARGS. If FROM_TTY is non-zero, be chatty about it. */ |
| 246 | |
| 247 | static void |
| 248 | inf_ptrace_detach (char *args, int from_tty) |
| 249 | { |
| 250 | pid_t pid = ptid_get_pid (inferior_ptid); |
| 251 | int sig = 0; |
| 252 | |
| 253 | if (from_tty) |
| 254 | { |
| 255 | char *exec_file = get_exec_file (0); |
| 256 | if (exec_file == 0) |
| 257 | exec_file = ""; |
| 258 | printf_unfiltered (_("Detaching from program: %s, %s\n"), exec_file, |
| 259 | target_pid_to_str (pid_to_ptid (pid))); |
| 260 | gdb_flush (gdb_stdout); |
| 261 | } |
| 262 | if (args) |
| 263 | sig = atoi (args); |
| 264 | |
| 265 | #ifdef PT_DETACH |
| 266 | /* We'd better not have left any breakpoints in the program or it'll |
| 267 | die when it hits one. Also note that this may only work if we |
| 268 | previously attached to the inferior. It *might* work if we |
| 269 | started the process ourselves. */ |
| 270 | errno = 0; |
| 271 | ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, sig); |
| 272 | if (errno != 0) |
| 273 | perror_with_name (("ptrace")); |
| 274 | attach_flag = 0; |
| 275 | #else |
| 276 | error (_("This system does not support detaching from a process")); |
| 277 | #endif |
| 278 | |
| 279 | inferior_ptid = null_ptid; |
| 280 | unpush_target (ptrace_ops_hack); |
| 281 | } |
| 282 | |
| 283 | /* Kill the inferior. */ |
| 284 | |
| 285 | static void |
| 286 | inf_ptrace_kill (void) |
| 287 | { |
| 288 | pid_t pid = ptid_get_pid (inferior_ptid); |
| 289 | int status; |
| 290 | |
| 291 | if (pid == 0) |
| 292 | return; |
| 293 | |
| 294 | ptrace (PT_KILL, pid, (PTRACE_TYPE_ARG3)0, 0); |
| 295 | waitpid (pid, &status, 0); |
| 296 | |
| 297 | target_mourn_inferior (); |
| 298 | } |
| 299 | |
| 300 | /* Stop the inferior. */ |
| 301 | |
| 302 | static void |
| 303 | inf_ptrace_stop (void) |
| 304 | { |
| 305 | /* Send a SIGINT to the process group. This acts just like the user |
| 306 | typed a ^C on the controlling terminal. Note that using a |
| 307 | negative process number in kill() is a System V-ism. The proper |
| 308 | BSD interface is killpg(). However, all modern BSDs support the |
| 309 | System V interface too. */ |
| 310 | kill (-inferior_process_group, SIGINT); |
| 311 | } |
| 312 | |
| 313 | /* Resume execution of thread PTID, or all threads if PTID is -1. If |
| 314 | STEP is nonzero, single-step it. If SIGNAL is nonzero, give it |
| 315 | that signal. */ |
| 316 | |
| 317 | static void |
| 318 | inf_ptrace_resume (ptid_t ptid, int step, enum target_signal signal) |
| 319 | { |
| 320 | pid_t pid = ptid_get_pid (ptid); |
| 321 | int request = PT_CONTINUE; |
| 322 | |
| 323 | if (pid == -1) |
| 324 | /* Resume all threads. Traditionally ptrace() only supports |
| 325 | single-threaded processes, so simply resume the inferior. */ |
| 326 | pid = ptid_get_pid (inferior_ptid); |
| 327 | |
| 328 | if (step) |
| 329 | { |
| 330 | /* If this system does not support PT_STEP, a higher level |
| 331 | function will have called single_step() to transmute the step |
| 332 | request into a continue request (by setting breakpoints on |
| 333 | all possible successor instructions), so we don't have to |
| 334 | worry about that here. */ |
| 335 | request = PT_STEP; |
| 336 | } |
| 337 | |
| 338 | /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from |
| 339 | where it was. If GDB wanted it to start some other way, we have |
| 340 | already written a new program counter value to the child. */ |
| 341 | errno = 0; |
| 342 | ptrace (request, pid, (PTRACE_TYPE_ARG3)1, target_signal_to_host (signal)); |
| 343 | if (errno != 0) |
| 344 | perror_with_name (("ptrace")); |
| 345 | } |
| 346 | |
| 347 | /* Wait for the child specified by PTID to do something. Return the |
| 348 | process ID of the child, or MINUS_ONE_PTID in case of error; store |
| 349 | the status in *OURSTATUS. */ |
| 350 | |
| 351 | static ptid_t |
| 352 | inf_ptrace_wait (ptid_t ptid, struct target_waitstatus *ourstatus) |
| 353 | { |
| 354 | pid_t pid; |
| 355 | int status, save_errno; |
| 356 | |
| 357 | do |
| 358 | { |
| 359 | set_sigint_trap (); |
| 360 | set_sigio_trap (); |
| 361 | |
| 362 | do |
| 363 | { |
| 364 | pid = waitpid (ptid_get_pid (ptid), &status, 0); |
| 365 | save_errno = errno; |
| 366 | } |
| 367 | while (pid == -1 && errno == EINTR); |
| 368 | |
| 369 | clear_sigio_trap (); |
| 370 | clear_sigint_trap (); |
| 371 | |
| 372 | if (pid == -1) |
| 373 | { |
| 374 | fprintf_unfiltered (gdb_stderr, |
| 375 | _("Child process unexpectedly missing: %s.\n"), |
| 376 | safe_strerror (save_errno)); |
| 377 | |
| 378 | /* Claim it exited with unknown signal. */ |
| 379 | ourstatus->kind = TARGET_WAITKIND_SIGNALLED; |
| 380 | ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; |
| 381 | return minus_one_ptid; |
| 382 | } |
| 383 | |
| 384 | /* Ignore terminated detached child processes. */ |
| 385 | if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid)) |
| 386 | pid = -1; |
| 387 | } |
| 388 | while (pid == -1); |
| 389 | |
| 390 | #ifdef PT_GET_PROCESS_STATE |
| 391 | if (WIFSTOPPED (status)) |
| 392 | { |
| 393 | ptrace_state_t pe; |
| 394 | pid_t fpid; |
| 395 | |
| 396 | if (ptrace (PT_GET_PROCESS_STATE, pid, |
| 397 | (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) |
| 398 | perror_with_name (("ptrace")); |
| 399 | |
| 400 | switch (pe.pe_report_event) |
| 401 | { |
| 402 | case PTRACE_FORK: |
| 403 | ourstatus->kind = TARGET_WAITKIND_FORKED; |
| 404 | ourstatus->value.related_pid = pe.pe_other_pid; |
| 405 | |
| 406 | /* Make sure the other end of the fork is stopped too. */ |
| 407 | fpid = waitpid (pe.pe_other_pid, &status, 0); |
| 408 | if (fpid == -1) |
| 409 | perror_with_name (("waitpid")); |
| 410 | |
| 411 | if (ptrace (PT_GET_PROCESS_STATE, fpid, |
| 412 | (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) |
| 413 | perror_with_name (("ptrace")); |
| 414 | |
| 415 | gdb_assert (pe.pe_report_event == PTRACE_FORK); |
| 416 | gdb_assert (pe.pe_other_pid == pid); |
| 417 | if (fpid == ptid_get_pid (inferior_ptid)) |
| 418 | { |
| 419 | ourstatus->value.related_pid = pe.pe_other_pid; |
| 420 | return pid_to_ptid (fpid); |
| 421 | } |
| 422 | |
| 423 | return pid_to_ptid (pid); |
| 424 | } |
| 425 | } |
| 426 | #endif |
| 427 | |
| 428 | store_waitstatus (ourstatus, status); |
| 429 | return pid_to_ptid (pid); |
| 430 | } |
| 431 | |
| 432 | /* Attempt a transfer all LEN bytes starting at OFFSET between the |
| 433 | inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer. |
| 434 | Return the number of bytes actually transferred. */ |
| 435 | |
| 436 | static LONGEST |
| 437 | inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object, |
| 438 | const char *annex, gdb_byte *readbuf, |
| 439 | const gdb_byte *writebuf, |
| 440 | ULONGEST offset, LONGEST len) |
| 441 | { |
| 442 | pid_t pid = ptid_get_pid (inferior_ptid); |
| 443 | |
| 444 | switch (object) |
| 445 | { |
| 446 | case TARGET_OBJECT_MEMORY: |
| 447 | #ifdef PT_IO |
| 448 | /* OpenBSD 3.1, NetBSD 1.6 and FreeBSD 5.0 have a new PT_IO |
| 449 | request that promises to be much more efficient in reading |
| 450 | and writing data in the traced process's address space. */ |
| 451 | { |
| 452 | struct ptrace_io_desc piod; |
| 453 | |
| 454 | /* NOTE: We assume that there are no distinct address spaces |
| 455 | for instruction and data. However, on OpenBSD 3.9 and |
| 456 | later, PIOD_WRITE_D doesn't allow changing memory that's |
| 457 | mapped read-only. Since most code segments will be |
| 458 | read-only, using PIOD_WRITE_D will prevent us from |
| 459 | inserting breakpoints, so we use PIOD_WRITE_I instead. */ |
| 460 | piod.piod_op = writebuf ? PIOD_WRITE_I : PIOD_READ_D; |
| 461 | piod.piod_addr = writebuf ? (void *) writebuf : readbuf; |
| 462 | piod.piod_offs = (void *) (long) offset; |
| 463 | piod.piod_len = len; |
| 464 | |
| 465 | errno = 0; |
| 466 | if (ptrace (PT_IO, pid, (caddr_t)&piod, 0) == 0) |
| 467 | /* Return the actual number of bytes read or written. */ |
| 468 | return piod.piod_len; |
| 469 | /* If the PT_IO request is somehow not supported, fallback on |
| 470 | using PT_WRITE_D/PT_READ_D. Otherwise we will return zero |
| 471 | to indicate failure. */ |
| 472 | if (errno != EINVAL) |
| 473 | return 0; |
| 474 | } |
| 475 | #endif |
| 476 | { |
| 477 | union |
| 478 | { |
| 479 | PTRACE_TYPE_RET word; |
| 480 | gdb_byte byte[sizeof (PTRACE_TYPE_RET)]; |
| 481 | } buffer; |
| 482 | ULONGEST rounded_offset; |
| 483 | LONGEST partial_len; |
| 484 | |
| 485 | /* Round the start offset down to the next long word |
| 486 | boundary. */ |
| 487 | rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET); |
| 488 | |
| 489 | /* Since ptrace will transfer a single word starting at that |
| 490 | rounded_offset the partial_len needs to be adjusted down to |
| 491 | that (remember this function only does a single transfer). |
| 492 | Should the required length be even less, adjust it down |
| 493 | again. */ |
| 494 | partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset; |
| 495 | if (partial_len > len) |
| 496 | partial_len = len; |
| 497 | |
| 498 | if (writebuf) |
| 499 | { |
| 500 | /* If OFFSET:PARTIAL_LEN is smaller than |
| 501 | ROUNDED_OFFSET:WORDSIZE then a read/modify write will |
| 502 | be needed. Read in the entire word. */ |
| 503 | if (rounded_offset < offset |
| 504 | || (offset + partial_len |
| 505 | < rounded_offset + sizeof (PTRACE_TYPE_RET))) |
| 506 | /* Need part of initial word -- fetch it. */ |
| 507 | buffer.word = ptrace (PT_READ_I, pid, |
| 508 | (PTRACE_TYPE_ARG3)(uintptr_t) |
| 509 | rounded_offset, 0); |
| 510 | |
| 511 | /* Copy data to be written over corresponding part of |
| 512 | buffer. */ |
| 513 | memcpy (buffer.byte + (offset - rounded_offset), |
| 514 | writebuf, partial_len); |
| 515 | |
| 516 | errno = 0; |
| 517 | ptrace (PT_WRITE_D, pid, |
| 518 | (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, |
| 519 | buffer.word); |
| 520 | if (errno) |
| 521 | { |
| 522 | /* Using the appropriate one (I or D) is necessary for |
| 523 | Gould NP1, at least. */ |
| 524 | errno = 0; |
| 525 | ptrace (PT_WRITE_I, pid, |
| 526 | (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, |
| 527 | buffer.word); |
| 528 | if (errno) |
| 529 | return 0; |
| 530 | } |
| 531 | } |
| 532 | |
| 533 | if (readbuf) |
| 534 | { |
| 535 | errno = 0; |
| 536 | buffer.word = ptrace (PT_READ_I, pid, |
| 537 | (PTRACE_TYPE_ARG3)(uintptr_t)rounded_offset, |
| 538 | 0); |
| 539 | if (errno) |
| 540 | return 0; |
| 541 | /* Copy appropriate bytes out of the buffer. */ |
| 542 | memcpy (readbuf, buffer.byte + (offset - rounded_offset), |
| 543 | partial_len); |
| 544 | } |
| 545 | |
| 546 | return partial_len; |
| 547 | } |
| 548 | |
| 549 | case TARGET_OBJECT_UNWIND_TABLE: |
| 550 | return -1; |
| 551 | |
| 552 | case TARGET_OBJECT_AUXV: |
| 553 | return -1; |
| 554 | |
| 555 | case TARGET_OBJECT_WCOOKIE: |
| 556 | return -1; |
| 557 | |
| 558 | default: |
| 559 | return -1; |
| 560 | } |
| 561 | } |
| 562 | |
| 563 | /* Return non-zero if the thread specified by PTID is alive. */ |
| 564 | |
| 565 | static int |
| 566 | inf_ptrace_thread_alive (ptid_t ptid) |
| 567 | { |
| 568 | /* ??? Is kill the right way to do this? */ |
| 569 | return (kill (ptid_get_pid (ptid), 0) != -1); |
| 570 | } |
| 571 | |
| 572 | /* Print status information about what we're accessing. */ |
| 573 | |
| 574 | static void |
| 575 | inf_ptrace_files_info (struct target_ops *ignore) |
| 576 | { |
| 577 | printf_filtered (_("\tUsing the running image of %s %s.\n"), |
| 578 | attach_flag ? "attached" : "child", |
| 579 | target_pid_to_str (inferior_ptid)); |
| 580 | } |
| 581 | |
| 582 | /* Create a prototype ptrace target. The client can override it with |
| 583 | local methods. */ |
| 584 | |
| 585 | struct target_ops * |
| 586 | inf_ptrace_target (void) |
| 587 | { |
| 588 | struct target_ops *t = inf_child_target (); |
| 589 | |
| 590 | t->to_attach = inf_ptrace_attach; |
| 591 | t->to_detach = inf_ptrace_detach; |
| 592 | t->to_resume = inf_ptrace_resume; |
| 593 | t->to_wait = inf_ptrace_wait; |
| 594 | t->to_files_info = inf_ptrace_files_info; |
| 595 | t->to_kill = inf_ptrace_kill; |
| 596 | t->to_create_inferior = inf_ptrace_create_inferior; |
| 597 | #ifdef PT_GET_PROCESS_STATE |
| 598 | t->to_follow_fork = inf_ptrace_follow_fork; |
| 599 | t->to_post_startup_inferior = inf_ptrace_post_startup_inferior; |
| 600 | t->to_post_attach = inf_ptrace_post_attach; |
| 601 | #endif |
| 602 | t->to_mourn_inferior = inf_ptrace_mourn_inferior; |
| 603 | t->to_thread_alive = inf_ptrace_thread_alive; |
| 604 | t->to_pid_to_str = normal_pid_to_str; |
| 605 | t->to_stop = inf_ptrace_stop; |
| 606 | t->to_xfer_partial = inf_ptrace_xfer_partial; |
| 607 | |
| 608 | ptrace_ops_hack = t; |
| 609 | return t; |
| 610 | } |
| 611 | \f |
| 612 | |
| 613 | /* Pointer to a function that returns the offset within the user area |
| 614 | where a particular register is stored. */ |
| 615 | static CORE_ADDR (*inf_ptrace_register_u_offset)(struct gdbarch *, int, int); |
| 616 | |
| 617 | /* Fetch register REGNUM from the inferior. */ |
| 618 | |
| 619 | static void |
| 620 | inf_ptrace_fetch_register (struct regcache *regcache, int regnum) |
| 621 | { |
| 622 | CORE_ADDR addr; |
| 623 | size_t size; |
| 624 | PTRACE_TYPE_RET *buf; |
| 625 | int pid, i; |
| 626 | |
| 627 | /* This isn't really an address, but ptrace thinks of it as one. */ |
| 628 | addr = inf_ptrace_register_u_offset (current_gdbarch, regnum, 0); |
| 629 | if (addr == (CORE_ADDR)-1 |
| 630 | || gdbarch_cannot_fetch_register (current_gdbarch, regnum)) |
| 631 | { |
| 632 | regcache_raw_supply (regcache, regnum, NULL); |
| 633 | return; |
| 634 | } |
| 635 | |
| 636 | /* Cater for systems like GNU/Linux, that implement threads as |
| 637 | separate processes. */ |
| 638 | pid = ptid_get_lwp (inferior_ptid); |
| 639 | if (pid == 0) |
| 640 | pid = ptid_get_pid (inferior_ptid); |
| 641 | |
| 642 | size = register_size (current_gdbarch, regnum); |
| 643 | gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); |
| 644 | buf = alloca (size); |
| 645 | |
| 646 | /* Read the register contents from the inferior a chunk at a time. */ |
| 647 | for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) |
| 648 | { |
| 649 | errno = 0; |
| 650 | buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, 0); |
| 651 | if (errno != 0) |
| 652 | error (_("Couldn't read register %s (#%d): %s."), |
| 653 | gdbarch_register_name (current_gdbarch, regnum), |
| 654 | regnum, safe_strerror (errno)); |
| 655 | |
| 656 | addr += sizeof (PTRACE_TYPE_RET); |
| 657 | } |
| 658 | regcache_raw_supply (regcache, regnum, buf); |
| 659 | } |
| 660 | |
| 661 | /* Fetch register REGNUM from the inferior. If REGNUM is -1, do this |
| 662 | for all registers. */ |
| 663 | |
| 664 | static void |
| 665 | inf_ptrace_fetch_registers (struct regcache *regcache, int regnum) |
| 666 | { |
| 667 | if (regnum == -1) |
| 668 | for (regnum = 0; regnum < gdbarch_num_regs (current_gdbarch); regnum++) |
| 669 | inf_ptrace_fetch_register (regcache, regnum); |
| 670 | else |
| 671 | inf_ptrace_fetch_register (regcache, regnum); |
| 672 | } |
| 673 | |
| 674 | /* Store register REGNUM into the inferior. */ |
| 675 | |
| 676 | static void |
| 677 | inf_ptrace_store_register (const struct regcache *regcache, int regnum) |
| 678 | { |
| 679 | CORE_ADDR addr; |
| 680 | size_t size; |
| 681 | PTRACE_TYPE_RET *buf; |
| 682 | int pid, i; |
| 683 | |
| 684 | /* This isn't really an address, but ptrace thinks of it as one. */ |
| 685 | addr = inf_ptrace_register_u_offset (current_gdbarch, regnum, 1); |
| 686 | if (addr == (CORE_ADDR)-1 |
| 687 | || gdbarch_cannot_store_register (current_gdbarch, regnum)) |
| 688 | return; |
| 689 | |
| 690 | /* Cater for systems like GNU/Linux, that implement threads as |
| 691 | separate processes. */ |
| 692 | pid = ptid_get_lwp (inferior_ptid); |
| 693 | if (pid == 0) |
| 694 | pid = ptid_get_pid (inferior_ptid); |
| 695 | |
| 696 | size = register_size (current_gdbarch, regnum); |
| 697 | gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0); |
| 698 | buf = alloca (size); |
| 699 | |
| 700 | /* Write the register contents into the inferior a chunk at a time. */ |
| 701 | regcache_raw_collect (regcache, regnum, buf); |
| 702 | for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++) |
| 703 | { |
| 704 | errno = 0; |
| 705 | ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, buf[i]); |
| 706 | if (errno != 0) |
| 707 | error (_("Couldn't write register %s (#%d): %s."), |
| 708 | gdbarch_register_name (current_gdbarch, regnum), |
| 709 | regnum, safe_strerror (errno)); |
| 710 | |
| 711 | addr += sizeof (PTRACE_TYPE_RET); |
| 712 | } |
| 713 | } |
| 714 | |
| 715 | /* Store register REGNUM back into the inferior. If REGNUM is -1, do |
| 716 | this for all registers. */ |
| 717 | |
| 718 | void |
| 719 | inf_ptrace_store_registers (struct regcache *regcache, int regnum) |
| 720 | { |
| 721 | if (regnum == -1) |
| 722 | for (regnum = 0; regnum < gdbarch_num_regs (current_gdbarch); regnum++) |
| 723 | inf_ptrace_store_register (regcache, regnum); |
| 724 | else |
| 725 | inf_ptrace_store_register (regcache, regnum); |
| 726 | } |
| 727 | |
| 728 | /* Create a "traditional" ptrace target. REGISTER_U_OFFSET should be |
| 729 | a function returning the offset within the user area where a |
| 730 | particular register is stored. */ |
| 731 | |
| 732 | struct target_ops * |
| 733 | inf_ptrace_trad_target (CORE_ADDR (*register_u_offset) |
| 734 | (struct gdbarch *, int, int)) |
| 735 | { |
| 736 | struct target_ops *t = inf_ptrace_target(); |
| 737 | |
| 738 | gdb_assert (register_u_offset); |
| 739 | inf_ptrace_register_u_offset = register_u_offset; |
| 740 | t->to_fetch_registers = inf_ptrace_fetch_registers; |
| 741 | t->to_store_registers = inf_ptrace_store_registers; |
| 742 | |
| 743 | return t; |
| 744 | } |