1/* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
2
3   Copyright (C) 1986-2023 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 3 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, see <http://www.gnu.org/licenses/>.  */
19
20#include "defs.h"
21#include "inferior.h"
22#include "target.h"
23#include "gdbcore.h"
24#include "symfile.h"
25#include "objfiles.h"
26#include "bfd.h"
27#include "gdb-stabs.h"
28#include "regcache.h"
29#include "arch-utils.h"
30#include "inf-child.h"
31#include "inf-ptrace.h"
32#include "ppc-tdep.h"
33#include "rs6000-aix-tdep.h"
34#include "exec.h"
35#include "observable.h"
36#include "xcoffread.h"
37
38#include <sys/ptrace.h>
39#include <sys/reg.h>
40
41#include <sys/dir.h>
42#include <sys/user.h>
43#include <signal.h>
44#include <sys/ioctl.h>
45#include <fcntl.h>
46
47#include <a.out.h>
48#include <sys/file.h>
49#include <sys/stat.h>
50#include "gdb_bfd.h"
51#include <sys/core.h>
52#define __LDINFO_PTRACE32__	/* for __ld_info32 */
53#define __LDINFO_PTRACE64__	/* for __ld_info64 */
54#include <sys/ldr.h>
55#include <sys/systemcfg.h>
56
57/* Header files for getting ppid in AIX of a child process.  */
58#include <procinfo.h>
59#include <sys/types.h>
60
61/* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
62   debugging 32-bit and 64-bit processes.  Define a typedef and macros for
63   accessing fields in the appropriate structures.  */
64
65/* In 32-bit compilation mode (which is the only mode from which ptrace()
66   works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */
67
68#if defined (__ld_info32) || defined (__ld_info64)
69# define ARCH3264
70#endif
71
72/* Return whether the current architecture is 64-bit.  */
73
74#ifndef ARCH3264
75# define ARCH64() 0
76#else
77# define ARCH64() (register_size (target_gdbarch (), 0) == 8)
78#endif
79
80class rs6000_nat_target final : public inf_ptrace_target
81{
82public:
83  void fetch_registers (struct regcache *, int) override;
84  void store_registers (struct regcache *, int) override;
85
86  enum target_xfer_status xfer_partial (enum target_object object,
87					const char *annex,
88					gdb_byte *readbuf,
89					const gdb_byte *writebuf,
90					ULONGEST offset, ULONGEST len,
91					ULONGEST *xfered_len) override;
92
93  void create_inferior (const char *, const std::string &,
94			char **, int) override;
95
96  ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
97
98  /* Fork detection related functions, For adding multi process debugging
99     support.  */
100  void follow_fork (inferior *, ptid_t, target_waitkind, bool, bool) override;
101
102protected:
103
104  void post_startup_inferior (ptid_t ptid) override;
105
106private:
107  enum target_xfer_status
108    xfer_shared_libraries (enum target_object object,
109			   const char *annex, gdb_byte *readbuf,
110			   const gdb_byte *writebuf,
111			   ULONGEST offset, ULONGEST len,
112			   ULONGEST *xfered_len);
113};
114
115static rs6000_nat_target the_rs6000_nat_target;
116
117/* The below declaration is to track number of times, parent has
118   reported fork event before its children.  */
119
120static std::list<pid_t> aix_pending_parent;
121
122/* The below declaration is for a child process event that
123   is reported before its corresponding parent process in
124   the event of a fork ().  */
125
126static std::list<pid_t> aix_pending_children;
127
128static void
129aix_remember_child (pid_t pid)
130{
131  aix_pending_children.push_front (pid);
132}
133
134static void
135aix_remember_parent (pid_t pid)
136{
137  aix_pending_parent.push_front (pid);
138}
139
140/* This function returns a parent of a child process.  */
141
142static pid_t
143find_my_aix_parent (pid_t child_pid)
144{
145  struct procsinfo ProcessBuffer1;
146
147  if (getprocs (&ProcessBuffer1, sizeof (ProcessBuffer1),
148		NULL, 0, &child_pid, 1) != 1)
149    return 0;
150  else
151    return ProcessBuffer1.pi_ppid;
152}
153
154/* In the below function we check if there was any child
155   process pending.  If it exists we return it from the
156   list, otherwise we return a null.  */
157
158static pid_t
159has_my_aix_child_reported (pid_t parent_pid)
160{
161  pid_t child = 0;
162  auto it = std::find_if (aix_pending_children.begin (),
163			  aix_pending_children.end (),
164			  [=] (pid_t child_pid)
165			  {
166			    return find_my_aix_parent (child_pid) == parent_pid;
167			  });
168  if (it != aix_pending_children.end ())
169    {
170      child = *it;
171      aix_pending_children.erase (it);
172    }
173  return child;
174}
175
176/* In the below function we check if there was any parent
177   process pending.  If it exists we return it from the
178   list, otherwise we return a null.  */
179
180static pid_t
181has_my_aix_parent_reported (pid_t child_pid)
182{
183  pid_t my_parent = find_my_aix_parent (child_pid);
184  auto it = std::find (aix_pending_parent.begin (),
185		       aix_pending_parent.end (),
186		       my_parent);
187  if (it != aix_pending_parent.end ())
188    {
189      aix_pending_parent.erase (it);
190      return my_parent;
191    }
192  return 0;
193}
194
195/* Given REGNO, a gdb register number, return the corresponding
196   number suitable for use as a ptrace() parameter.  Return -1 if
197   there's no suitable mapping.  Also, set the int pointed to by
198   ISFLOAT to indicate whether REGNO is a floating point register.  */
199
200static int
201regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
202{
203  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
204
205  *isfloat = 0;
206  if (tdep->ppc_gp0_regnum <= regno
207      && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
208    return regno;
209  else if (tdep->ppc_fp0_regnum >= 0
210	   && tdep->ppc_fp0_regnum <= regno
211	   && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
212    {
213      *isfloat = 1;
214      return regno - tdep->ppc_fp0_regnum + FPR0;
215    }
216  else if (regno == gdbarch_pc_regnum (gdbarch))
217    return IAR;
218  else if (regno == tdep->ppc_ps_regnum)
219    return MSR;
220  else if (regno == tdep->ppc_cr_regnum)
221    return CR;
222  else if (regno == tdep->ppc_lr_regnum)
223    return LR;
224  else if (regno == tdep->ppc_ctr_regnum)
225    return CTR;
226  else if (regno == tdep->ppc_xer_regnum)
227    return XER;
228  else if (tdep->ppc_fpscr_regnum >= 0
229	   && regno == tdep->ppc_fpscr_regnum)
230    return FPSCR;
231  else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
232    return MQ;
233  else
234    return -1;
235}
236
237/* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
238
239static int
240rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
241{
242#ifdef HAVE_PTRACE64
243  int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
244#else
245  int ret = ptrace (req, id, (int *)addr, data, buf);
246#endif
247#if 0
248  printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
249	  req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
250#endif
251  return ret;
252}
253
254/* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
255
256static int
257rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
258{
259#ifdef ARCH3264
260#  ifdef HAVE_PTRACE64
261  int ret = ptrace64 (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
262#  else
263  int ret = ptracex (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
264#  endif
265#else
266  int ret = 0;
267#endif
268#if 0
269  printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
270	  req, id, hex_string (addr), data, (unsigned int)buf, ret);
271#endif
272  return ret;
273}
274
275void rs6000_nat_target::post_startup_inferior (ptid_t ptid)
276{
277
278  /* In AIX to turn on multi process debugging in ptrace
279     PT_MULTI is the option to be passed,
280     with the process ID which can fork () and
281     the data parameter [fourth parameter] must be 1.  */
282
283  if (!ARCH64 ())
284    rs6000_ptrace32 (PT_MULTI, ptid.pid(), 0, 1, 0);
285  else
286    rs6000_ptrace64 (PT_MULTI, ptid.pid(), 0, 1, 0);
287}
288
289void
290rs6000_nat_target::follow_fork (inferior *child_inf, ptid_t child_ptid,
291				target_waitkind fork_kind, bool follow_child,
292				bool detach_fork)
293{
294
295  /* Once the fork event is detected the infrun.c code
296     calls the target_follow_fork to take care of
297     follow child and detach the child activity which is
298     done using the function below.  */
299
300  inf_ptrace_target::follow_fork (child_inf, child_ptid, fork_kind,
301				  follow_child, detach_fork);
302
303  /* If we detach fork and follow child we do not want the child
304     process to geneate events that ptrace can trace.  Hence we
305     detach it.  */
306
307  if (detach_fork && !follow_child)
308  {
309    if (ARCH64 ())
310      rs6000_ptrace64 (PT_DETACH, child_ptid.pid (), 0, 0, 0);
311    else
312      rs6000_ptrace32 (PT_DETACH, child_ptid.pid (), 0, 0, 0);
313  }
314}
315
316/* Fetch register REGNO from the inferior.  */
317
318static void
319fetch_register (struct regcache *regcache, int regno)
320{
321  struct gdbarch *gdbarch = regcache->arch ();
322  int addr[PPC_MAX_REGISTER_SIZE];
323  int nr, isfloat;
324  pid_t pid = regcache->ptid ().pid ();
325
326  /* Retrieved values may be -1, so infer errors from errno.  */
327  errno = 0;
328
329  nr = regmap (gdbarch, regno, &isfloat);
330
331  /* Floating-point registers.  */
332  if (isfloat)
333    rs6000_ptrace32 (PT_READ_FPR, pid, addr, nr, 0);
334
335  /* Bogus register number.  */
336  else if (nr < 0)
337    {
338      if (regno >= gdbarch_num_regs (gdbarch))
339	gdb_printf (gdb_stderr,
340		    "gdb error: register no %d not implemented.\n",
341		    regno);
342      return;
343    }
344
345  /* Fixed-point registers.  */
346  else
347    {
348      if (!ARCH64 ())
349	*addr = rs6000_ptrace32 (PT_READ_GPR, pid, (int *) nr, 0, 0);
350      else
351	{
352	  /* PT_READ_GPR requires the buffer parameter to point to long long,
353	     even if the register is really only 32 bits.  */
354	  long long buf;
355	  rs6000_ptrace64 (PT_READ_GPR, pid, nr, 0, &buf);
356	  if (register_size (gdbarch, regno) == 8)
357	    memcpy (addr, &buf, 8);
358	  else
359	    *addr = buf;
360	}
361    }
362
363  if (!errno)
364    regcache->raw_supply (regno, (char *) addr);
365  else
366    {
367#if 0
368      /* FIXME: this happens 3 times at the start of each 64-bit program.  */
369      perror (_("ptrace read"));
370#endif
371      errno = 0;
372    }
373}
374
375/* Store register REGNO back into the inferior.  */
376
377static void
378store_register (struct regcache *regcache, int regno)
379{
380  struct gdbarch *gdbarch = regcache->arch ();
381  int addr[PPC_MAX_REGISTER_SIZE];
382  int nr, isfloat;
383  pid_t pid = regcache->ptid ().pid ();
384
385  /* Fetch the register's value from the register cache.  */
386  regcache->raw_collect (regno, addr);
387
388  /* -1 can be a successful return value, so infer errors from errno.  */
389  errno = 0;
390
391  nr = regmap (gdbarch, regno, &isfloat);
392
393  /* Floating-point registers.  */
394  if (isfloat)
395    rs6000_ptrace32 (PT_WRITE_FPR, pid, addr, nr, 0);
396
397  /* Bogus register number.  */
398  else if (nr < 0)
399    {
400      if (regno >= gdbarch_num_regs (gdbarch))
401	gdb_printf (gdb_stderr,
402		    "gdb error: register no %d not implemented.\n",
403		    regno);
404    }
405
406  /* Fixed-point registers.  */
407  else
408    {
409      /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
410	 the register's value is passed by value, but for 64-bit inferiors,
411	 the address of a buffer containing the value is passed.  */
412      if (!ARCH64 ())
413	rs6000_ptrace32 (PT_WRITE_GPR, pid, (int *) nr, *addr, 0);
414      else
415	{
416	  /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
417	     area, even if the register is really only 32 bits.  */
418	  long long buf;
419	  if (register_size (gdbarch, regno) == 8)
420	    memcpy (&buf, addr, 8);
421	  else
422	    buf = *addr;
423	  rs6000_ptrace64 (PT_WRITE_GPR, pid, nr, 0, &buf);
424	}
425    }
426
427  if (errno)
428    {
429      perror (_("ptrace write"));
430      errno = 0;
431    }
432}
433
434/* Read from the inferior all registers if REGNO == -1 and just register
435   REGNO otherwise.  */
436
437void
438rs6000_nat_target::fetch_registers (struct regcache *regcache, int regno)
439{
440  struct gdbarch *gdbarch = regcache->arch ();
441  if (regno != -1)
442    fetch_register (regcache, regno);
443
444  else
445    {
446      ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
447
448      /* Read 32 general purpose registers.  */
449      for (regno = tdep->ppc_gp0_regnum;
450	   regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
451	   regno++)
452	{
453	  fetch_register (regcache, regno);
454	}
455
456      /* Read general purpose floating point registers.  */
457      if (tdep->ppc_fp0_regnum >= 0)
458	for (regno = 0; regno < ppc_num_fprs; regno++)
459	  fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
460
461      /* Read special registers.  */
462      fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
463      fetch_register (regcache, tdep->ppc_ps_regnum);
464      fetch_register (regcache, tdep->ppc_cr_regnum);
465      fetch_register (regcache, tdep->ppc_lr_regnum);
466      fetch_register (regcache, tdep->ppc_ctr_regnum);
467      fetch_register (regcache, tdep->ppc_xer_regnum);
468      if (tdep->ppc_fpscr_regnum >= 0)
469	fetch_register (regcache, tdep->ppc_fpscr_regnum);
470      if (tdep->ppc_mq_regnum >= 0)
471	fetch_register (regcache, tdep->ppc_mq_regnum);
472    }
473}
474
475/* Store our register values back into the inferior.
476   If REGNO is -1, do this for all registers.
477   Otherwise, REGNO specifies which register (so we can save time).  */
478
479void
480rs6000_nat_target::store_registers (struct regcache *regcache, int regno)
481{
482  struct gdbarch *gdbarch = regcache->arch ();
483  if (regno != -1)
484    store_register (regcache, regno);
485
486  else
487    {
488      ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
489
490      /* Write general purpose registers first.  */
491      for (regno = tdep->ppc_gp0_regnum;
492	   regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
493	   regno++)
494	{
495	  store_register (regcache, regno);
496	}
497
498      /* Write floating point registers.  */
499      if (tdep->ppc_fp0_regnum >= 0)
500	for (regno = 0; regno < ppc_num_fprs; regno++)
501	  store_register (regcache, tdep->ppc_fp0_regnum + regno);
502
503      /* Write special registers.  */
504      store_register (regcache, gdbarch_pc_regnum (gdbarch));
505      store_register (regcache, tdep->ppc_ps_regnum);
506      store_register (regcache, tdep->ppc_cr_regnum);
507      store_register (regcache, tdep->ppc_lr_regnum);
508      store_register (regcache, tdep->ppc_ctr_regnum);
509      store_register (regcache, tdep->ppc_xer_regnum);
510      if (tdep->ppc_fpscr_regnum >= 0)
511	store_register (regcache, tdep->ppc_fpscr_regnum);
512      if (tdep->ppc_mq_regnum >= 0)
513	store_register (regcache, tdep->ppc_mq_regnum);
514    }
515}
516
517/* Implement the to_xfer_partial target_ops method.  */
518
519enum target_xfer_status
520rs6000_nat_target::xfer_partial (enum target_object object,
521				 const char *annex, gdb_byte *readbuf,
522				 const gdb_byte *writebuf,
523				 ULONGEST offset, ULONGEST len,
524				 ULONGEST *xfered_len)
525{
526  pid_t pid = inferior_ptid.pid ();
527  int arch64 = ARCH64 ();
528
529  switch (object)
530    {
531    case TARGET_OBJECT_LIBRARIES_AIX:
532      return xfer_shared_libraries (object, annex,
533				    readbuf, writebuf,
534				    offset, len, xfered_len);
535    case TARGET_OBJECT_MEMORY:
536      {
537	union
538	{
539	  PTRACE_TYPE_RET word;
540	  gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
541	} buffer;
542	ULONGEST rounded_offset;
543	LONGEST partial_len;
544
545	/* Round the start offset down to the next long word
546	   boundary.  */
547	rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
548
549	/* Since ptrace will transfer a single word starting at that
550	   rounded_offset the partial_len needs to be adjusted down to
551	   that (remember this function only does a single transfer).
552	   Should the required length be even less, adjust it down
553	   again.  */
554	partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
555	if (partial_len > len)
556	  partial_len = len;
557
558	if (writebuf)
559	  {
560	    /* If OFFSET:PARTIAL_LEN is smaller than
561	       ROUNDED_OFFSET:WORDSIZE then a read/modify write will
562	       be needed.  Read in the entire word.  */
563	    if (rounded_offset < offset
564		|| (offset + partial_len
565		    < rounded_offset + sizeof (PTRACE_TYPE_RET)))
566	      {
567		/* Need part of initial word -- fetch it.  */
568		if (arch64)
569		  buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
570						 rounded_offset, 0, NULL);
571		else
572		  buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
573						 (int *) (uintptr_t)
574						 rounded_offset,
575						 0, NULL);
576	      }
577
578	    /* Copy data to be written over corresponding part of
579	       buffer.  */
580	    memcpy (buffer.byte + (offset - rounded_offset),
581		    writebuf, partial_len);
582
583	    errno = 0;
584	    if (arch64)
585	      rs6000_ptrace64 (PT_WRITE_D, pid,
586			       rounded_offset, buffer.word, NULL);
587	    else
588	      rs6000_ptrace32 (PT_WRITE_D, pid,
589			       (int *) (uintptr_t) rounded_offset,
590			       buffer.word, NULL);
591	    if (errno)
592	      return TARGET_XFER_EOF;
593	  }
594
595	if (readbuf)
596	  {
597	    errno = 0;
598	    if (arch64)
599	      buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
600					     rounded_offset, 0, NULL);
601	    else
602	      buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
603					     (int *)(uintptr_t)rounded_offset,
604					     0, NULL);
605	    if (errno)
606	      return TARGET_XFER_EOF;
607
608	    /* Copy appropriate bytes out of the buffer.  */
609	    memcpy (readbuf, buffer.byte + (offset - rounded_offset),
610		    partial_len);
611	  }
612
613	*xfered_len = (ULONGEST) partial_len;
614	return TARGET_XFER_OK;
615      }
616
617    default:
618      return TARGET_XFER_E_IO;
619    }
620}
621
622/* Wait for the child specified by PTID to do something.  Return the
623   process ID of the child, or MINUS_ONE_PTID in case of error; store
624   the status in *OURSTATUS.  */
625
626ptid_t
627rs6000_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
628			 target_wait_flags options)
629{
630  pid_t pid;
631  int status, save_errno;
632
633  while (1)
634    {
635      set_sigint_trap ();
636
637      do
638	{
639	  pid = waitpid (ptid.pid (), &status, 0);
640	  save_errno = errno;
641	}
642      while (pid == -1 && errno == EINTR);
643
644      clear_sigint_trap ();
645
646      if (pid == -1)
647	{
648	  gdb_printf (gdb_stderr,
649		      _("Child process unexpectedly missing: %s.\n"),
650		      safe_strerror (save_errno));
651
652	  ourstatus->set_ignore ();
653	  return minus_one_ptid;
654	}
655
656      /* Ignore terminated detached child processes.  */
657      if (!WIFSTOPPED (status) && find_inferior_pid (this, pid) == nullptr)
658	continue;
659
660      /* Check for a fork () event.  */
661      if ((status & 0xff) == W_SFWTED)
662	{
663	  /* Checking whether it is a parent or a child event.  */
664
665	  /* If the event is a child we check if there was a parent
666	     event recorded before.  If yes we got the parent child
667	     relationship.  If not we push this child and wait for
668	     the next fork () event.  */
669	  if (find_inferior_pid (this, pid) == nullptr)
670	    {
671	      pid_t parent_pid = has_my_aix_parent_reported (pid);
672	      if (parent_pid > 0)
673		{
674		  ourstatus->set_forked (ptid_t (pid));
675		  return ptid_t (parent_pid);
676		}
677	      aix_remember_child (pid);
678	    }
679
680	  /* If the event is a parent we check if there was a child
681	     event recorded before.  If yes we got the parent child
682	     relationship.  If not we push this parent and wait for
683	     the next fork () event.  */
684	  else
685	    {
686	      pid_t child_pid = has_my_aix_child_reported (pid);
687	      if (child_pid > 0)
688		{
689		  ourstatus->set_forked (ptid_t (child_pid));
690		  return ptid_t (pid);
691		}
692	      aix_remember_parent (pid);
693	    }
694	  continue;
695	}
696
697      break;
698    }
699
700  /* AIX has a couple of strange returns from wait().  */
701
702  /* stop after load" status.  */
703  if (status == 0x57c)
704    ourstatus->set_loaded ();
705  /* 0x7f is signal 0.  0x17f and 0x137f are status returned
706     if we follow parent, a switch is made to a child post parent
707     execution and child continues its execution [user switches
708     to child and presses continue].  */
709  else if (status == 0x7f || status == 0x17f || status == 0x137f)
710    ourstatus->set_spurious ();
711  /* A normal waitstatus.  Let the usual macros deal with it.  */
712  else
713    *ourstatus = host_status_to_waitstatus (status);
714
715  return ptid_t (pid);
716}
717
718
719/* Set the current architecture from the host running GDB.  Called when
720   starting a child process.  */
721
722void
723rs6000_nat_target::create_inferior (const char *exec_file,
724				    const std::string &allargs,
725				    char **env, int from_tty)
726{
727  enum bfd_architecture arch;
728  unsigned long mach;
729  bfd abfd;
730
731  inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
732
733  if (__power_rs ())
734    {
735      arch = bfd_arch_rs6000;
736      mach = bfd_mach_rs6k;
737    }
738  else
739    {
740      arch = bfd_arch_powerpc;
741      mach = bfd_mach_ppc;
742    }
743
744  /* FIXME: schauer/2002-02-25:
745     We don't know if we are executing a 32 or 64 bit executable,
746     and have no way to pass the proper word size to rs6000_gdbarch_init.
747     So we have to avoid switching to a new architecture, if the architecture
748     matches already.
749     Blindly calling rs6000_gdbarch_init used to work in older versions of
750     GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
751     determine the wordsize.  */
752  if (current_program_space->exec_bfd ())
753    {
754      const struct bfd_arch_info *exec_bfd_arch_info;
755
756      exec_bfd_arch_info
757	= bfd_get_arch_info (current_program_space->exec_bfd ());
758      if (arch == exec_bfd_arch_info->arch)
759	return;
760    }
761
762  bfd_default_set_arch_mach (&abfd, arch, mach);
763
764  gdbarch_info info;
765  info.bfd_arch_info = bfd_get_arch_info (&abfd);
766  info.abfd = current_program_space->exec_bfd ();
767
768  if (!gdbarch_update_p (info))
769    internal_error (_("rs6000_create_inferior: failed "
770		      "to select architecture"));
771}
772
773
774/* Shared Object support.  */
775
776/* Return the LdInfo data for the given process.  Raises an error
777   if the data could not be obtained.  */
778
779static gdb::byte_vector
780rs6000_ptrace_ldinfo (ptid_t ptid)
781{
782  const int pid = ptid.pid ();
783  gdb::byte_vector ldi (1024);
784  int rc = -1;
785
786  while (1)
787    {
788      if (ARCH64 ())
789	rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi.data (),
790			      ldi.size (), NULL);
791      else
792	rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi.data (),
793			      ldi.size (), NULL);
794
795      if (rc != -1)
796	break; /* Success, we got the entire ld_info data.  */
797
798      if (errno != ENOMEM)
799	perror_with_name (_("ptrace ldinfo"));
800
801      /* ldi is not big enough.  Double it and try again.  */
802      ldi.resize (ldi.size () * 2);
803    }
804
805  return ldi;
806}
807
808/* Implement the to_xfer_partial target_ops method for
809   TARGET_OBJECT_LIBRARIES_AIX objects.  */
810
811enum target_xfer_status
812rs6000_nat_target::xfer_shared_libraries
813  (enum target_object object,
814   const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
815   ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
816{
817  ULONGEST result;
818
819  /* This function assumes that it is being run with a live process.
820     Core files are handled via gdbarch.  */
821  gdb_assert (target_has_execution ());
822
823  if (writebuf)
824    return TARGET_XFER_E_IO;
825
826  gdb::byte_vector ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
827  result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf.data (),
828				      readbuf, offset, len, 1);
829
830  if (result == 0)
831    return TARGET_XFER_EOF;
832  else
833    {
834      *xfered_len = result;
835      return TARGET_XFER_OK;
836    }
837}
838
839void _initialize_rs6000_nat ();
840void
841_initialize_rs6000_nat ()
842{
843  add_inf_child_target (&the_rs6000_nat_target);
844}
845