gdb/rs6000-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2013 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 "libbfd.h"             /* For bfd_default_set_arch_mach (FIXME) */
  27 #include "bfd.h"
  28 #include "exceptions.h"
  29 #include "gdb-stabs.h"
  30 #include "regcache.h"
  31 #include "arch-utils.h"
  32 #include "inf-child.h"
  33 #include "inf-ptrace.h"
  34 #include "ppc-tdep.h"
  35 #include "rs6000-tdep.h"
  36 #include "rs6000-aix-tdep.h"
  37 #include "exec.h"
  38 #include "observer.h"
  39 #include "xcoffread.h"
  40
  41 #include <sys/ptrace.h>
  42 #include <sys/reg.h>
  43
  44 #include <sys/dir.h>
  45 #include <sys/user.h>
  46 #include <signal.h>
  47 #include <sys/ioctl.h>
  48 #include <fcntl.h>
  49 #include <errno.h>
  50
  51 #include <a.out.h>
  52 #include <sys/file.h>
  53 #include "gdb_stat.h"
  54 #include "gdb_bfd.h"
  55 #include <sys/core.h>
  56 #define __LDINFO_PTRACE32__     /* for __ld_info32 */
  57 #define __LDINFO_PTRACE64__     /* for __ld_info64 */
  58 #include <sys/ldr.h>
  59 #include <sys/systemcfg.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 #ifdef __ld_info32
  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
  80 static void exec_one_dummy_insn (struct regcache *);
  81
  82 static LONGEST rs6000_xfer_shared_libraries
  83   (struct target_ops *ops, enum target_object object,
  84    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
  85    ULONGEST offset, LONGEST len);
  86
  87 /* Given REGNO, a gdb register number, return the corresponding
  88    number suitable for use as a ptrace() parameter.  Return -1 if
  89    there's no suitable mapping.  Also, set the int pointed to by
  90    ISFLOAT to indicate whether REGNO is a floating point register.  */
  91
  92 static int
  93 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  94 {
  95   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  96
  97   *isfloat = 0;
  98   if (tdep->ppc_gp0_regnum <= regno
  99       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
 100     return regno;
 101   else if (tdep->ppc_fp0_regnum >= 0
 102            && tdep->ppc_fp0_regnum <= regno
 103            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 104     {
 105       *isfloat = 1;
 106       return regno - tdep->ppc_fp0_regnum + FPR0;
 107     }
 108   else if (regno == gdbarch_pc_regnum (gdbarch))
 109     return IAR;
 110   else if (regno == tdep->ppc_ps_regnum)
 111     return MSR;
 112   else if (regno == tdep->ppc_cr_regnum)
 113     return CR;
 114   else if (regno == tdep->ppc_lr_regnum)
 115     return LR;
 116   else if (regno == tdep->ppc_ctr_regnum)
 117     return CTR;
 118   else if (regno == tdep->ppc_xer_regnum)
 119     return XER;
 120   else if (tdep->ppc_fpscr_regnum >= 0
 121            && regno == tdep->ppc_fpscr_regnum)
 122     return FPSCR;
 123   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 124     return MQ;
 125   else
 126     return -1;
 127 }
 128
 129 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 130
 131 static int
 132 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 133 {
 134   int ret = ptrace (req, id, (int *)addr, data, buf);
 135 #if 0
 136   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 137           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 138 #endif
 139   return ret;
 140 }
 141
 142 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 143
 144 static int
 145 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 146 {
 147 #ifdef ARCH3264
 148   int ret = ptracex (req, id, addr, data, buf);
 149 #else
 150   int ret = 0;
 151 #endif
 152 #if 0
 153   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 154           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 155 #endif
 156   return ret;
 157 }
 158
 159 /* Fetch register REGNO from the inferior.  */
 160
 161 static void
 162 fetch_register (struct regcache *regcache, int regno)
 163 {
 164   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 165   int addr[MAX_REGISTER_SIZE];
 166   int nr, isfloat;
 167
 168   /* Retrieved values may be -1, so infer errors from errno.  */
 169   errno = 0;
 170
 171   nr = regmap (gdbarch, regno, &isfloat);
 172
 173   /* Floating-point registers.  */
 174   if (isfloat)
 175     rs6000_ptrace32 (PT_READ_FPR, PIDGET (inferior_ptid), addr, nr, 0);
 176
 177   /* Bogus register number.  */
 178   else if (nr < 0)
 179     {
 180       if (regno >= gdbarch_num_regs (gdbarch))
 181         fprintf_unfiltered (gdb_stderr,
 182                             "gdb error: register no %d not implemented.\n",
 183                             regno);
 184       return;
 185     }
 186
 187   /* Fixed-point registers.  */
 188   else
 189     {
 190       if (!ARCH64 ())
 191         *addr = rs6000_ptrace32 (PT_READ_GPR, PIDGET (inferior_ptid),
 192                                  (int *) nr, 0, 0);
 193       else
 194         {
 195           /* PT_READ_GPR requires the buffer parameter to point to long long,
 196              even if the register is really only 32 bits.  */
 197           long long buf;
 198           rs6000_ptrace64 (PT_READ_GPR, PIDGET (inferior_ptid), nr, 0, &buf);
 199           if (register_size (gdbarch, regno) == 8)
 200             memcpy (addr, &buf, 8);
 201           else
 202             *addr = buf;
 203         }
 204     }
 205
 206   if (!errno)
 207     regcache_raw_supply (regcache, regno, (char *) addr);
 208   else
 209     {
 210 #if 0
 211       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 212       perror (_("ptrace read"));
 213 #endif
 214       errno = 0;
 215     }
 216 }
 217
 218 /* Store register REGNO back into the inferior.  */
 219
 220 static void
 221 store_register (struct regcache *regcache, int regno)
 222 {
 223   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 224   int addr[MAX_REGISTER_SIZE];
 225   int nr, isfloat;
 226
 227   /* Fetch the register's value from the register cache.  */
 228   regcache_raw_collect (regcache, regno, addr);
 229
 230   /* -1 can be a successful return value, so infer errors from errno.  */
 231   errno = 0;
 232
 233   nr = regmap (gdbarch, regno, &isfloat);
 234
 235   /* Floating-point registers.  */
 236   if (isfloat)
 237     rs6000_ptrace32 (PT_WRITE_FPR, PIDGET (inferior_ptid), addr, nr, 0);
 238
 239   /* Bogus register number.  */
 240   else if (nr < 0)
 241     {
 242       if (regno >= gdbarch_num_regs (gdbarch))
 243         fprintf_unfiltered (gdb_stderr,
 244                             "gdb error: register no %d not implemented.\n",
 245                             regno);
 246     }
 247
 248   /* Fixed-point registers.  */
 249   else
 250     {
 251       if (regno == gdbarch_sp_regnum (gdbarch))
 252         /* Execute one dummy instruction (which is a breakpoint) in inferior
 253            process to give kernel a chance to do internal housekeeping.
 254            Otherwise the following ptrace(2) calls will mess up user stack
 255            since kernel will get confused about the bottom of the stack
 256            (%sp).  */
 257         exec_one_dummy_insn (regcache);
 258
 259       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 260          the register's value is passed by value, but for 64-bit inferiors,
 261          the address of a buffer containing the value is passed.  */
 262       if (!ARCH64 ())
 263         rs6000_ptrace32 (PT_WRITE_GPR, PIDGET (inferior_ptid),
 264                          (int *) nr, *addr, 0);
 265       else
 266         {
 267           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 268              area, even if the register is really only 32 bits.  */
 269           long long buf;
 270           if (register_size (gdbarch, regno) == 8)
 271             memcpy (&buf, addr, 8);
 272           else
 273             buf = *addr;
 274           rs6000_ptrace64 (PT_WRITE_GPR, PIDGET (inferior_ptid), nr, 0, &buf);
 275         }
 276     }
 277
 278   if (errno)
 279     {
 280       perror (_("ptrace write"));
 281       errno = 0;
 282     }
 283 }
 284
 285 /* Read from the inferior all registers if REGNO == -1 and just register
 286    REGNO otherwise.  */
 287
 288 static void
 289 rs6000_fetch_inferior_registers (struct target_ops *ops,
 290                                  struct regcache *regcache, int regno)
 291 {
 292   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 293   if (regno != -1)
 294     fetch_register (regcache, regno);
 295
 296   else
 297     {
 298       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 299
 300       /* Read 32 general purpose registers.  */
 301       for (regno = tdep->ppc_gp0_regnum;
 302            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 303            regno++)
 304         {
 305           fetch_register (regcache, regno);
 306         }
 307
 308       /* Read general purpose floating point registers.  */
 309       if (tdep->ppc_fp0_regnum >= 0)
 310         for (regno = 0; regno < ppc_num_fprs; regno++)
 311           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 312
 313       /* Read special registers.  */
 314       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 315       fetch_register (regcache, tdep->ppc_ps_regnum);
 316       fetch_register (regcache, tdep->ppc_cr_regnum);
 317       fetch_register (regcache, tdep->ppc_lr_regnum);
 318       fetch_register (regcache, tdep->ppc_ctr_regnum);
 319       fetch_register (regcache, tdep->ppc_xer_regnum);
 320       if (tdep->ppc_fpscr_regnum >= 0)
 321         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 322       if (tdep->ppc_mq_regnum >= 0)
 323         fetch_register (regcache, tdep->ppc_mq_regnum);
 324     }
 325 }
 326
 327 /* Store our register values back into the inferior.
 328    If REGNO is -1, do this for all registers.
 329    Otherwise, REGNO specifies which register (so we can save time).  */
 330
 331 static void
 332 rs6000_store_inferior_registers (struct target_ops *ops,
 333                                  struct regcache *regcache, int regno)
 334 {
 335   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 336   if (regno != -1)
 337     store_register (regcache, regno);
 338
 339   else
 340     {
 341       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 342
 343       /* Write general purpose registers first.  */
 344       for (regno = tdep->ppc_gp0_regnum;
 345            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 346            regno++)
 347         {
 348           store_register (regcache, regno);
 349         }
 350
 351       /* Write floating point registers.  */
 352       if (tdep->ppc_fp0_regnum >= 0)
 353         for (regno = 0; regno < ppc_num_fprs; regno++)
 354           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 355
 356       /* Write special registers.  */
 357       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 358       store_register (regcache, tdep->ppc_ps_regnum);
 359       store_register (regcache, tdep->ppc_cr_regnum);
 360       store_register (regcache, tdep->ppc_lr_regnum);
 361       store_register (regcache, tdep->ppc_ctr_regnum);
 362       store_register (regcache, tdep->ppc_xer_regnum);
 363       if (tdep->ppc_fpscr_regnum >= 0)
 364         store_register (regcache, tdep->ppc_fpscr_regnum);
 365       if (tdep->ppc_mq_regnum >= 0)
 366         store_register (regcache, tdep->ppc_mq_regnum);
 367     }
 368 }
 369
 370
 371 /* Attempt a transfer all LEN bytes starting at OFFSET between the
 372    inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer.
 373    Return the number of bytes actually transferred.  */
 374
 375 static LONGEST
 376 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 377                      const char *annex, gdb_byte *readbuf,
 378                      const gdb_byte *writebuf,
 379                      ULONGEST offset, LONGEST len)
 380 {
 381   pid_t pid = ptid_get_pid (inferior_ptid);
 382   int arch64 = ARCH64 ();
 383
 384   switch (object)
 385     {
 386     case TARGET_OBJECT_LIBRARIES_AIX:
 387       return rs6000_xfer_shared_libraries (ops, object, annex,
 388                                            readbuf, writebuf,
 389                                            offset, len);
 390     case TARGET_OBJECT_MEMORY:
 391       {
 392         union
 393         {
 394           PTRACE_TYPE_RET word;
 395           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 396         } buffer;
 397         ULONGEST rounded_offset;
 398         LONGEST partial_len;
 399
 400         /* Round the start offset down to the next long word
 401            boundary.  */
 402         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 403
 404         /* Since ptrace will transfer a single word starting at that
 405            rounded_offset the partial_len needs to be adjusted down to
 406            that (remember this function only does a single transfer).
 407            Should the required length be even less, adjust it down
 408            again.  */
 409         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 410         if (partial_len > len)
 411           partial_len = len;
 412
 413         if (writebuf)
 414           {
 415             /* If OFFSET:PARTIAL_LEN is smaller than
 416                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 417                be needed.  Read in the entire word.  */
 418             if (rounded_offset < offset
 419                 || (offset + partial_len
 420                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 421               {
 422                 /* Need part of initial word -- fetch it.  */
 423                 if (arch64)
 424                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 425                                                  rounded_offset, 0, NULL);
 426                 else
 427                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 428                                                  (int *) (uintptr_t)
 429                                                  rounded_offset,
 430                                                  0, NULL);
 431               }
 432
 433             /* Copy data to be written over corresponding part of
 434                buffer.  */
 435             memcpy (buffer.byte + (offset - rounded_offset),
 436                     writebuf, partial_len);
 437
 438             errno = 0;
 439             if (arch64)
 440               rs6000_ptrace64 (PT_WRITE_D, pid,
 441                                rounded_offset, buffer.word, NULL);
 442             else
 443               rs6000_ptrace32 (PT_WRITE_D, pid,
 444                                (int *) (uintptr_t) rounded_offset,
 445                                buffer.word, NULL);
 446             if (errno)
 447               return 0;
 448           }
 449
 450         if (readbuf)
 451           {
 452             errno = 0;
 453             if (arch64)
 454               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 455                                              rounded_offset, 0, NULL);
 456             else
 457               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 458                                              (int *)(uintptr_t)rounded_offset,
 459                                              0, NULL);
 460             if (errno)
 461               return 0;
 462
 463             /* Copy appropriate bytes out of the buffer.  */
 464             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 465                     partial_len);
 466           }
 467
 468         return partial_len;
 469       }
 470
 471     default:
 472       return -1;
 473     }
 474 }
 475
 476 /* Wait for the child specified by PTID to do something.  Return the
 477    process ID of the child, or MINUS_ONE_PTID in case of error; store
 478    the status in *OURSTATUS.  */
 479
 480 static ptid_t
 481 rs6000_wait (struct target_ops *ops,
 482              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 483 {
 484   pid_t pid;
 485   int status, save_errno;
 486
 487   do
 488     {
 489       set_sigint_trap ();
 490
 491       do
 492         {
 493           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 494           save_errno = errno;
 495         }
 496       while (pid == -1 && errno == EINTR);
 497
 498       clear_sigint_trap ();
 499
 500       if (pid == -1)
 501         {
 502           fprintf_unfiltered (gdb_stderr,
 503                               _("Child process unexpectedly missing: %s.\n"),
 504                               safe_strerror (save_errno));
 505
 506           /* Claim it exited with unknown signal.  */
 507           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 508           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 509           return inferior_ptid;
 510         }
 511
 512       /* Ignore terminated detached child processes.  */
 513       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 514         pid = -1;
 515     }
 516   while (pid == -1);
 517
 518   /* AIX has a couple of strange returns from wait().  */
 519
 520   /* stop after load" status.  */
 521   if (status == 0x57c)
 522     ourstatus->kind = TARGET_WAITKIND_LOADED;
 523   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 524   else if (status == 0x7f)
 525     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 526   /* A normal waitstatus.  Let the usual macros deal with it.  */
 527   else
 528     store_waitstatus (ourstatus, status);
 529
 530   return pid_to_ptid (pid);
 531 }
 532
 533 /* Execute one dummy breakpoint instruction.  This way we give the kernel
 534    a chance to do some housekeeping and update inferior's internal data,
 535    including u_area.  */
 536
 537 static void
 538 exec_one_dummy_insn (struct regcache *regcache)
 539 {
 540 #define DUMMY_INSN_ADDR AIX_TEXT_SEGMENT_BASE+0x200
 541
 542   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 543   int ret, status, pid;
 544   CORE_ADDR prev_pc;
 545   void *bp;
 546
 547   /* We plant one dummy breakpoint into DUMMY_INSN_ADDR address.  We
 548      assume that this address will never be executed again by the real
 549      code.  */
 550
 551   bp = deprecated_insert_raw_breakpoint (gdbarch, NULL, DUMMY_INSN_ADDR);
 552
 553   /* You might think this could be done with a single ptrace call, and
 554      you'd be correct for just about every platform I've ever worked
 555      on.  However, rs6000-ibm-aix4.1.3 seems to have screwed this up --
 556      the inferior never hits the breakpoint (it's also worth noting
 557      powerpc-ibm-aix4.1.3 works correctly).  */
 558   prev_pc = regcache_read_pc (regcache);
 559   regcache_write_pc (regcache, DUMMY_INSN_ADDR);
 560   if (ARCH64 ())
 561     ret = rs6000_ptrace64 (PT_CONTINUE, PIDGET (inferior_ptid), 1, 0, NULL);
 562   else
 563     ret = rs6000_ptrace32 (PT_CONTINUE, PIDGET (inferior_ptid),
 564                            (int *) 1, 0, NULL);
 565
 566   if (ret != 0)
 567     perror (_("pt_continue"));
 568
 569   do
 570     {
 571       pid = waitpid (PIDGET (inferior_ptid), &status, 0);
 572     }
 573   while (pid != PIDGET (inferior_ptid));
 574
 575   regcache_write_pc (regcache, prev_pc);
 576   deprecated_remove_raw_breakpoint (gdbarch, bp);
 577 }
 578 \f
 579
 580 /* Set the current architecture from the host running GDB.  Called when
 581    starting a child process.  */
 582
 583 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 584                                       char *allargs, char **env, int from_tty);
 585 static void
 586 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 587                         char *allargs, char **env, int from_tty)
 588 {
 589   enum bfd_architecture arch;
 590   unsigned long mach;
 591   bfd abfd;
 592   struct gdbarch_info info;
 593
 594   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 595
 596   if (__power_rs ())
 597     {
 598       arch = bfd_arch_rs6000;
 599       mach = bfd_mach_rs6k;
 600     }
 601   else
 602     {
 603       arch = bfd_arch_powerpc;
 604       mach = bfd_mach_ppc;
 605     }
 606
 607   /* FIXME: schauer/2002-02-25:
 608      We don't know if we are executing a 32 or 64 bit executable,
 609      and have no way to pass the proper word size to rs6000_gdbarch_init.
 610      So we have to avoid switching to a new architecture, if the architecture
 611      matches already.
 612      Blindly calling rs6000_gdbarch_init used to work in older versions of
 613      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 614      determine the wordsize.  */
 615   if (exec_bfd)
 616     {
 617       const struct bfd_arch_info *exec_bfd_arch_info;
 618
 619       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 620       if (arch == exec_bfd_arch_info->arch)
 621         return;
 622     }
 623
 624   bfd_default_set_arch_mach (&abfd, arch, mach);
 625
 626   gdbarch_info_init (&info);
 627   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 628   info.abfd = exec_bfd;
 629
 630   if (!gdbarch_update_p (info))
 631     internal_error (__FILE__, __LINE__,
 632                     _("rs6000_create_inferior: failed "
 633                       "to select architecture"));
 634 }
 635 \f
 636
 637 /* Shared Object support.  */
 638
 639 /* Return the LdInfo data for the given process.  Raises an error
 640    if the data could not be obtained.
 641
 642    The returned value must be deallocated after use.  */
 643
 644 static gdb_byte *
 645 rs6000_ptrace_ldinfo (ptid_t ptid)
 646 {
 647   const int pid = ptid_get_pid (ptid);
 648   int ldi_size = 1024;
 649   gdb_byte *ldi = xmalloc (ldi_size);
 650   int rc = -1;
 651
 652   while (1)
 653     {
 654       if (ARCH64 ())
 655         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 656                               NULL);
 657       else
 658         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 659
 660       if (rc != -1)
 661         break; /* Success, we got the entire ld_info data.  */
 662
 663       if (errno != ENOMEM)
 664         perror_with_name (_("ptrace ldinfo"));
 665
 666       /* ldi is not big enough.  Double it and try again.  */
 667       ldi_size *= 2;
 668       ldi = xrealloc (ldi, ldi_size);
 669     }
 670
 671   return ldi;
 672 }
 673
 674 /* Implement the to_xfer_partial target_ops method for
 675    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 676
 677 static LONGEST
 678 rs6000_xfer_shared_libraries
 679   (struct target_ops *ops, enum target_object object,
 680    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 681    ULONGEST offset, LONGEST len)
 682 {
 683   gdb_byte *ldi_buf;
 684   ULONGEST result;
 685   struct cleanup *cleanup;
 686
 687   /* This function assumes that it is being run with a live process.
 688      Core files are handled via gdbarch.  */
 689   gdb_assert (target_has_execution);
 690
 691   if (writebuf)
 692     return -1;
 693
 694   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 695   gdb_assert (ldi_buf != NULL);
 696   cleanup = make_cleanup (xfree, ldi_buf);
 697   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 698                                       readbuf, offset, len, 1);
 699   xfree (ldi_buf);
 700
 701   do_cleanups (cleanup);
 702   return result;
 703 }
 704
 705 void _initialize_rs6000_nat (void);
 706
 707 void
 708 _initialize_rs6000_nat (void)
 709 {
 710   struct target_ops *t;
 711
 712   t = inf_ptrace_target ();
 713   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 714   t->to_store_registers = rs6000_store_inferior_registers;
 715   t->to_xfer_partial = rs6000_xfer_partial;
 716
 717   super_create_inferior = t->to_create_inferior;
 718   t->to_create_inferior = rs6000_create_inferior;
 719
 720   t->to_wait = rs6000_wait;
 721
 722   add_target (t);
 723 }