1 /* Low level Unix child interface to ptrace, for GDB when running under Unix.
3 Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
4 1998, 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
6 This file is part of GDB.
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 2 of the License, or
11 (at your option) any later version.
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.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
25 #include "gdb_ptrace.h"
31 #include "inf-child.h"
33 #include "gdb_string.h"
38 /* HACK: Save the ptrace ops returned by ptrace_target. */
39 static struct target_ops
*ptrace_ops_hack
;
42 inf_ptrace_kill_inferior (void)
45 int pid
= PIDGET (inferior_ptid
);
50 /* This once used to call "kill" to kill the inferior just in case
51 the inferior was still running. As others have noted in the past
52 (kingdon) there shouldn't be any way to get here if the inferior
53 is still running -- else there's a major problem elsewere in gdb
54 and it needs to be fixed.
56 The kill call causes problems under hpux10, so it's been removed;
57 if this causes problems we'll deal with them as they arise. */
58 ptrace (PT_KILL
, pid
, (PTRACE_TYPE_ARG3
) 0, 0);
60 target_mourn_inferior ();
63 /* Resume execution of the inferior process. If STEP is nonzero,
64 single-step it. If SIGNAL is nonzero, give it that signal. */
67 inf_ptrace_resume (ptid_t ptid
, int step
, enum target_signal signal
)
69 int request
= PT_CONTINUE
;
70 int pid
= PIDGET (ptid
);
73 /* Resume all threads. */
74 /* I think this only gets used in the non-threaded case, where
75 "resume all threads" and "resume inferior_ptid" are the
77 pid
= PIDGET (inferior_ptid
);
81 /* If this system does not support PT_STEP, a higher level
82 function will have called single_step() to transmute the step
83 request into a continue request (by setting breakpoints on
84 all possible successor instructions), so we don't have to
85 worry about that here. */
89 /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from
90 where it was. If GDB wanted it to start some other way, we have
91 already written a new PC value to the child. */
93 ptrace (request
, pid
, (PTRACE_TYPE_ARG3
) 1, target_signal_to_host (signal
));
95 perror_with_name ("ptrace");
98 /* Wait for child to do something. Return pid of child, or -1 in case
99 of error; store status through argument pointer OURSTATUS. */
102 inf_ptrace_wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
)
106 char *execd_pathname
= NULL
;
110 enum target_waitkind kind
;
115 set_sigint_trap (); /* Causes SIGINT to be passed on to the
119 pid
= wait (&status
);
125 clear_sigint_trap ();
129 if (save_errno
== EINTR
)
132 fprintf_unfiltered (gdb_stderr
,
133 "Child process unexpectedly missing: %s.\n",
134 safe_strerror (save_errno
));
136 /* Claim it exited with unknown signal. */
137 ourstatus
->kind
= TARGET_WAITKIND_SIGNALLED
;
138 ourstatus
->value
.sig
= TARGET_SIGNAL_UNKNOWN
;
139 return pid_to_ptid (-1);
144 if (target_has_exited (pid
, status
, &exit_status
))
146 /* ??rehrauer: For now, ignore this. */
150 if (!target_thread_alive (pid_to_ptid (pid
)))
152 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
153 return pid_to_ptid (pid
);
156 while (pid
!= PIDGET (inferior_ptid
)); /* Some other child died or stopped */
158 store_waitstatus (ourstatus
, status
);
159 return pid_to_ptid (pid
);
162 /* Check to see if the given thread is alive.
164 FIXME: Is kill() ever the right way to do this? I doubt it, but
165 for now we're going to try and be compatable with the old thread
169 inf_ptrace_thread_alive (ptid_t ptid
)
171 pid_t pid
= PIDGET (ptid
);
173 return (kill (pid
, 0) != -1);
176 /* Attach to process PID, then initialize for debugging it. */
179 inf_ptrace_attach (char *args
, int from_tty
)
186 error_no_arg ("process-id to attach");
189 pid
= strtol (args
, &dummy
, 0);
190 /* Some targets don't set errno on errors, grrr! */
191 if (pid
== 0 && args
== dummy
)
192 error ("Illegal process-id: %s\n", args
);
194 if (pid
== getpid ()) /* Trying to masturbate? */
195 error ("I refuse to debug myself!");
199 exec_file
= (char *) get_exec_file (0);
202 printf_unfiltered ("Attaching to program: %s, %s\n", exec_file
,
203 target_pid_to_str (pid_to_ptid (pid
)));
205 printf_unfiltered ("Attaching to %s\n",
206 target_pid_to_str (pid_to_ptid (pid
)));
208 gdb_flush (gdb_stdout
);
213 ptrace (PT_ATTACH
, pid
, (PTRACE_TYPE_ARG3
) 0, 0);
215 perror_with_name ("ptrace");
218 error ("This system does not support attaching to a process");
221 inferior_ptid
= pid_to_ptid (pid
);
222 push_target (ptrace_ops_hack
);
226 inf_ptrace_post_attach (int pid
)
228 /* This version of Unix doesn't require a meaningful "post attach"
229 operation by a debugger. */
232 /* Take a program previously attached to and detaches it. The program
233 resumes execution and will no longer stop on signals, etc. We'd
234 better not have left any breakpoints in the program or it'll die
235 when it hits one. For this to work, it may be necessary for the
236 process to have been previously attached. It *might* work if the
237 program was started via the normal ptrace (PTRACE_TRACEME). */
240 inf_ptrace_detach (char *args
, int from_tty
)
243 int pid
= PIDGET (inferior_ptid
);
247 char *exec_file
= get_exec_file (0);
250 printf_unfiltered ("Detaching from program: %s, %s\n", exec_file
,
251 target_pid_to_str (pid_to_ptid (pid
)));
252 gdb_flush (gdb_stdout
);
259 ptrace (PT_DETACH
, pid
, (PTRACE_TYPE_ARG3
) 1, sig
);
261 perror_with_name ("ptrace");
264 error ("This system does not support detaching from a process");
267 inferior_ptid
= null_ptid
;
268 unpush_target (ptrace_ops_hack
);
271 /* Get ready to modify the registers array. On machines which store
272 individual registers, this doesn't need to do anything. On
273 machines which store all the registers in one fell swoop, this
274 makes sure that registers contains all the registers from the
275 program being debugged. */
278 inf_ptrace_prepare_to_store (void)
282 /* Print status information about what we're accessing. */
285 inf_ptrace_files_info (struct target_ops
*ignore
)
287 printf_unfiltered ("\tUsing the running image of %s %s.\n",
288 attach_flag
? "attached" : "child",
289 target_pid_to_str (inferior_ptid
));
293 inf_ptrace_open (char *arg
, int from_tty
)
295 error ("Use the \"run\" command to start a Unix child process.");
298 /* Stub function which causes the inferior that runs it, to be ptrace-able
299 by its parent process. */
304 /* "Trace me, Dr. Memory!" */
305 ptrace (0, 0, (PTRACE_TYPE_ARG3
) 0, 0);
308 /* Stub function which causes the GDB that runs it, to start ptrace-ing
309 the child process. */
312 inf_ptrace_him (int pid
)
314 push_target (ptrace_ops_hack
);
316 /* On some targets, there must be some explicit synchronization
317 between the parent and child processes after the debugger
318 forks, and before the child execs the debuggee program. This
319 call basically gives permission for the child to exec.
322 target_acknowledge_created_inferior (pid
);
324 /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h,
325 * and will be 1 or 2 depending on whether we're starting
326 * without or with a shell.
328 startup_inferior (START_INFERIOR_TRAPS_EXPECTED
);
330 /* On some targets, there must be some explicit actions taken after
331 the inferior has been started up.
333 target_post_startup_inferior (pid_to_ptid (pid
));
336 /* Start an inferior Unix child process and sets inferior_ptid to its
337 pid. EXEC_FILE is the file to run. ALLARGS is a string containing
338 the arguments to the program. ENV is the environment vector to
339 pass. Errors reported with error(). */
342 inf_ptrace_create_inferior (char *exec_file
, char *allargs
, char **env
,
345 fork_inferior (exec_file
, allargs
, env
, inf_ptrace_me
, inf_ptrace_him
,
347 /* We are at the first instruction we care about. */
348 observer_notify_inferior_created (¤t_target
, from_tty
);
349 /* Pedal to the metal... */
350 proceed ((CORE_ADDR
) -1, TARGET_SIGNAL_0
, 0);
354 inf_ptrace_post_startup_inferior (ptid_t ptid
)
356 /* This version of Unix doesn't require a meaningful "post startup inferior"
357 operation by a debugger.
362 inf_ptrace_acknowledge_created_inferior (int pid
)
364 /* This version of Unix doesn't require a meaningful "acknowledge created inferior"
365 operation by a debugger.
370 inf_ptrace_insert_fork_catchpoint (int pid
)
372 /* This version of Unix doesn't support notification of fork events. */
377 inf_ptrace_remove_fork_catchpoint (int pid
)
379 /* This version of Unix doesn't support notification of fork events. */
384 inf_ptrace_insert_vfork_catchpoint (int pid
)
386 /* This version of Unix doesn't support notification of vfork events. */
391 inf_ptrace_remove_vfork_catchpoint (int pid
)
393 /* This version of Unix doesn't support notification of vfork events. */
398 inf_ptrace_follow_fork (int follow_child
)
400 /* This version of Unix doesn't support following fork or vfork events. */
405 inf_ptrace_insert_exec_catchpoint (int pid
)
407 /* This version of Unix doesn't support notification of exec events. */
412 inf_ptrace_remove_exec_catchpoint (int pid
)
414 /* This version of Unix doesn't support notification of exec events. */
419 inf_ptrace_reported_exec_events_per_exec_call (void)
421 /* This version of Unix doesn't support notification of exec events.
427 inf_ptrace_has_exited (int pid
, int wait_status
, int *exit_status
)
429 if (WIFEXITED (wait_status
))
431 *exit_status
= WEXITSTATUS (wait_status
);
435 if (WIFSIGNALED (wait_status
))
437 *exit_status
= 0; /* ?? Don't know what else to say here. */
441 /* ?? Do we really need to consult the event state, too? Assume the
442 wait_state alone suffices.
448 inf_ptrace_mourn_inferior (void)
450 unpush_target (ptrace_ops_hack
);
451 generic_mourn_inferior ();
455 inf_ptrace_can_run (void)
460 /* Send a SIGINT to the process group. This acts just like the user
461 typed a ^C on the controlling terminal.
463 XXX - This may not be correct for all systems. Some may want to
464 use killpg() instead of kill (-pgrp). */
467 inf_ptrace_stop (void)
469 kill (-inferior_process_group
, SIGINT
);
472 /* Perform a partial transfer to/from the specified object. For
473 memory transfers, fall back to the old memory xfer functions. */
476 inf_ptrace_xfer_partial (struct target_ops
*ops
, enum target_object object
,
477 const char *annex
, void *readbuf
,
478 const void *writebuf
, ULONGEST offset
, LONGEST len
)
482 case TARGET_OBJECT_MEMORY
:
484 /* OpenBSD 3.1, NetBSD 1.6 and FreeBSD 5.0 have a new PT_IO
485 request that promises to be much more efficient in reading
486 and writing data in the traced process's address space. */
488 struct ptrace_io_desc piod
;
490 /* NOTE: We assume that there are no distinct address spaces
491 for instruction and data. */
492 piod
.piod_op
= writebuf
? PIOD_WRITE_D
: PIOD_READ_D
;
493 piod
.piod_addr
= writebuf
? (void *) writebuf
: readbuf
;
494 piod
.piod_offs
= (void *) (long) offset
;
498 if (ptrace (PT_IO
, PIDGET (inferior_ptid
), (caddr_t
) &piod
, 0) == 0)
499 /* Return the actual number of bytes read or written. */
500 return piod
.piod_len
;
501 /* If the PT_IO request is somehow not supported, fallback on
502 using PT_WRITE_D/PT_READ_D. Otherwise we will return zero
503 to indicate failure. */
511 PTRACE_TYPE_RET word
;
512 unsigned char byte
[sizeof (PTRACE_TYPE_RET
)];
514 ULONGEST rounded_offset
;
517 /* Round the start offset down to the next long word
519 rounded_offset
= offset
& -(ULONGEST
) sizeof (PTRACE_TYPE_RET
);
521 /* Since ptrace will transfer a single word starting at that
522 rounded_offset the partial_len needs to be adjusted down to
523 that (remember this function only does a single transfer).
524 Should the required length be even less, adjust it down
526 partial_len
= (rounded_offset
+ sizeof (PTRACE_TYPE_RET
)) - offset
;
527 if (partial_len
> len
)
532 /* If OFFSET:PARTIAL_LEN is smaller than
533 ROUNDED_OFFSET:WORDSIZE then a read/modify write will
534 be needed. Read in the entire word. */
535 if (rounded_offset
< offset
536 || (offset
+ partial_len
537 < rounded_offset
+ sizeof (PTRACE_TYPE_RET
)))
538 /* Need part of initial word -- fetch it. */
539 buffer
.word
= ptrace (PT_READ_I
, PIDGET (inferior_ptid
),
540 (PTRACE_TYPE_ARG3
) (long) rounded_offset
,
543 /* Copy data to be written over corresponding part of
545 memcpy (buffer
.byte
+ (offset
- rounded_offset
), writebuf
, partial_len
);
548 ptrace (PT_WRITE_D
, PIDGET (inferior_ptid
),
549 (PTRACE_TYPE_ARG3
) (long) rounded_offset
,
553 /* Using the appropriate one (I or D) is necessary for
554 Gould NP1, at least. */
556 ptrace (PT_WRITE_I
, PIDGET (inferior_ptid
),
557 (PTRACE_TYPE_ARG3
) (long) rounded_offset
,
566 buffer
.word
= ptrace (PT_READ_I
, PIDGET (inferior_ptid
),
567 (PTRACE_TYPE_ARG3
) (long) rounded_offset
, 0);
570 /* Copy appropriate bytes out of the buffer. */
571 memcpy (readbuf
, buffer
.byte
+ (offset
- rounded_offset
),
577 case TARGET_OBJECT_UNWIND_TABLE
:
580 case TARGET_OBJECT_AUXV
:
583 case TARGET_OBJECT_WCOOKIE
:
592 inf_ptrace_pid_to_str (ptid_t ptid
)
594 return normal_pid_to_str (ptid
);
598 inf_ptrace_target (void)
600 struct target_ops
*t
= inf_child_target ();
601 t
->to_open
= inf_ptrace_open
;
602 t
->to_attach
= inf_ptrace_attach
;
603 t
->to_post_attach
= inf_ptrace_post_attach
;
604 t
->to_detach
= inf_ptrace_detach
;
605 t
->to_resume
= inf_ptrace_resume
;
606 t
->to_wait
= inf_ptrace_wait
;
607 t
->to_prepare_to_store
= inf_ptrace_prepare_to_store
;
608 t
->to_xfer_partial
= inf_ptrace_xfer_partial
;
609 t
->to_files_info
= inf_ptrace_files_info
;
610 t
->to_kill
= inf_ptrace_kill_inferior
;
611 t
->to_create_inferior
= inf_ptrace_create_inferior
;
612 t
->to_post_startup_inferior
= inf_ptrace_post_startup_inferior
;
613 t
->to_acknowledge_created_inferior
=
614 inf_ptrace_acknowledge_created_inferior
;
615 t
->to_insert_fork_catchpoint
= inf_ptrace_insert_fork_catchpoint
;
616 t
->to_remove_fork_catchpoint
= inf_ptrace_remove_fork_catchpoint
;
617 t
->to_insert_vfork_catchpoint
= inf_ptrace_insert_vfork_catchpoint
;
618 t
->to_remove_vfork_catchpoint
= inf_ptrace_remove_vfork_catchpoint
;
619 t
->to_follow_fork
= inf_ptrace_follow_fork
;
620 t
->to_insert_exec_catchpoint
= inf_ptrace_insert_exec_catchpoint
;
621 t
->to_remove_exec_catchpoint
= inf_ptrace_remove_exec_catchpoint
;
622 t
->to_reported_exec_events_per_exec_call
=
623 inf_ptrace_reported_exec_events_per_exec_call
;
624 t
->to_has_exited
= inf_ptrace_has_exited
;
625 t
->to_mourn_inferior
= inf_ptrace_mourn_inferior
;
626 t
->to_can_run
= inf_ptrace_can_run
;
627 t
->to_thread_alive
= inf_ptrace_thread_alive
;
628 t
->to_pid_to_str
= inf_ptrace_pid_to_str
;
629 t
->to_stop
= inf_ptrace_stop
;
630 t
->to_stratum
= process_stratum
;
631 t
->to_has_all_memory
= 1;
632 t
->to_has_memory
= 1;
634 t
->to_has_registers
= 1;
635 t
->to_has_execution
= 1;
636 t
->to_magic
= OPS_MAGIC
;