gdb/fbsd-tdep.c

   1 /* Target-dependent code for FreeBSD, architecture-independent.
   2
   3    Copyright (C) 2002-2017 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 "auxv.h"
  22 #include "gdbcore.h"
  23 #include "inferior.h"
  24 #include "regcache.h"
  25 #include "regset.h"
  26 #include "gdbthread.h"
  27 #include "xml-syscall.h"
  28
  29 #include "elf-bfd.h"
  30 #include "fbsd-tdep.h"
  31
  32
  33 /* FreeBSD kernels 12.0 and later include a copy of the
  34    'ptrace_lwpinfo' structure returned by the PT_LWPINFO ptrace
  35    operation in an ELF core note (NT_FREEBSD_PTLWPINFO) for each LWP.
  36    The constants below define the offset of field members and flags in
  37    this structure used by methods in this file.  Note that the
  38    'ptrace_lwpinfo' struct in the note is preceded by a 4 byte integer
  39    containing the size of the structure.  */
  40
  41 #define LWPINFO_OFFSET          0x4
  42
  43 /* Offsets in ptrace_lwpinfo.  */
  44 #define LWPINFO_PL_FLAGS        0x8
  45 #define LWPINFO64_PL_SIGINFO    0x30
  46 #define LWPINFO32_PL_SIGINFO    0x2c
  47
  48 /* Flags in pl_flags.  */
  49 #define PL_FLAG_SI      0x20    /* siginfo is valid */
  50
  51 /* Sizes of siginfo_t.  */
  52 #define SIZE64_SIGINFO_T        80
  53 #define SIZE32_SIGINFO_T        64
  54
  55 static struct gdbarch_data *fbsd_gdbarch_data_handle;
  56
  57 struct fbsd_gdbarch_data
  58   {
  59     struct type *siginfo_type;
  60   };
  61
  62 static void *
  63 init_fbsd_gdbarch_data (struct gdbarch *gdbarch)
  64 {
  65   return GDBARCH_OBSTACK_ZALLOC (gdbarch, struct fbsd_gdbarch_data);
  66 }
  67
  68 static struct fbsd_gdbarch_data *
  69 get_fbsd_gdbarch_data (struct gdbarch *gdbarch)
  70 {
  71   return ((struct fbsd_gdbarch_data *)
  72           gdbarch_data (gdbarch, fbsd_gdbarch_data_handle));
  73 }
  74
  75 /* This is how we want PTIDs from core files to be printed.  */
  76
  77 static const char *
  78 fbsd_core_pid_to_str (struct gdbarch *gdbarch, ptid_t ptid)
  79 {
  80   static char buf[80];
  81
  82   if (ptid_get_lwp (ptid) != 0)
  83     {
  84       xsnprintf (buf, sizeof buf, "LWP %ld", ptid_get_lwp (ptid));
  85       return buf;
  86     }
  87
  88   return normal_pid_to_str (ptid);
  89 }
  90
  91 /* Extract the name assigned to a thread from a core.  Returns the
  92    string in a static buffer.  */
  93
  94 static const char *
  95 fbsd_core_thread_name (struct gdbarch *gdbarch, struct thread_info *thr)
  96 {
  97   static char buf[80];
  98   struct bfd_section *section;
  99   bfd_size_type size;
 100
 101   if (ptid_get_lwp (thr->ptid) != 0)
 102     {
 103       /* FreeBSD includes a NT_FREEBSD_THRMISC note for each thread
 104          whose contents are defined by a "struct thrmisc" declared in
 105          <sys/procfs.h> on FreeBSD.  The per-thread name is stored as
 106          a null-terminated string as the first member of the
 107          structure.  Rather than define the full structure here, just
 108          extract the null-terminated name from the start of the
 109          note.  */
 110       thread_section_name section_name (".thrmisc", thr->ptid);
 111
 112       section = bfd_get_section_by_name (core_bfd, section_name.c_str ());
 113       if (section != NULL && bfd_section_size (core_bfd, section) > 0)
 114         {
 115           /* Truncate the name if it is longer than "buf".  */
 116           size = bfd_section_size (core_bfd, section);
 117           if (size > sizeof buf - 1)
 118             size = sizeof buf - 1;
 119           if (bfd_get_section_contents (core_bfd, section, buf, (file_ptr) 0,
 120                                         size)
 121               && buf[0] != '\0')
 122             {
 123               buf[size] = '\0';
 124
 125               /* Note that each thread will report the process command
 126                  as its thread name instead of an empty name if a name
 127                  has not been set explicitly.  Return a NULL name in
 128                  that case.  */
 129               if (strcmp (buf, elf_tdata (core_bfd)->core->program) != 0)
 130                 return buf;
 131             }
 132         }
 133     }
 134
 135   return NULL;
 136 }
 137
 138 /* Implement the "core_xfer_siginfo" gdbarch method.  */
 139
 140 static LONGEST
 141 fbsd_core_xfer_siginfo (struct gdbarch *gdbarch, gdb_byte *readbuf,
 142                         ULONGEST offset, ULONGEST len)
 143 {
 144   size_t siginfo_size;
 145
 146   if (gdbarch_long_bit (gdbarch) == 32)
 147     siginfo_size = SIZE32_SIGINFO_T;
 148   else
 149     siginfo_size = SIZE64_SIGINFO_T;
 150   if (offset > siginfo_size)
 151     return -1;
 152
 153   thread_section_name section_name (".note.freebsdcore.lwpinfo", inferior_ptid);
 154   asection *section = bfd_get_section_by_name (core_bfd, section_name.c_str ());
 155   if (section == NULL)
 156     return -1;
 157
 158   gdb_byte buf[4];
 159   if (!bfd_get_section_contents (core_bfd, section, buf,
 160                                  LWPINFO_OFFSET + LWPINFO_PL_FLAGS, 4))
 161     return -1;
 162
 163   int pl_flags = extract_signed_integer (buf, 4, gdbarch_byte_order (gdbarch));
 164   if (!(pl_flags & PL_FLAG_SI))
 165     return -1;
 166
 167   if (offset + len > siginfo_size)
 168     len = siginfo_size - offset;
 169
 170   ULONGEST siginfo_offset;
 171   if (gdbarch_long_bit (gdbarch) == 32)
 172     siginfo_offset = LWPINFO_OFFSET + LWPINFO32_PL_SIGINFO;
 173   else
 174     siginfo_offset = LWPINFO_OFFSET + LWPINFO64_PL_SIGINFO;
 175
 176   if (!bfd_get_section_contents (core_bfd, section, readbuf,
 177                                  siginfo_offset + offset, len))
 178     return -1;
 179
 180   return len;
 181 }
 182
 183 static int
 184 find_signalled_thread (struct thread_info *info, void *data)
 185 {
 186   if (info->suspend.stop_signal != GDB_SIGNAL_0
 187       && ptid_get_pid (info->ptid) == ptid_get_pid (inferior_ptid))
 188     return 1;
 189
 190   return 0;
 191 }
 192
 193 /* Structure for passing information from
 194    fbsd_collect_thread_registers via an iterator to
 195    fbsd_collect_regset_section_cb. */
 196
 197 struct fbsd_collect_regset_section_cb_data
 198 {
 199   const struct regcache *regcache;
 200   bfd *obfd;
 201   char *note_data;
 202   int *note_size;
 203   unsigned long lwp;
 204   enum gdb_signal stop_signal;
 205   int abort_iteration;
 206 };
 207
 208 static void
 209 fbsd_collect_regset_section_cb (const char *sect_name, int size,
 210                                 const struct regset *regset,
 211                                 const char *human_name, void *cb_data)
 212 {
 213   char *buf;
 214   struct fbsd_collect_regset_section_cb_data *data
 215     = (struct fbsd_collect_regset_section_cb_data *) cb_data;
 216
 217   if (data->abort_iteration)
 218     return;
 219
 220   gdb_assert (regset->collect_regset);
 221
 222   buf = (char *) xmalloc (size);
 223   regset->collect_regset (regset, data->regcache, -1, buf, size);
 224
 225   /* PRSTATUS still needs to be treated specially.  */
 226   if (strcmp (sect_name, ".reg") == 0)
 227     data->note_data = (char *) elfcore_write_prstatus
 228       (data->obfd, data->note_data, data->note_size, data->lwp,
 229        gdb_signal_to_host (data->stop_signal), buf);
 230   else
 231     data->note_data = (char *) elfcore_write_register_note
 232       (data->obfd, data->note_data, data->note_size,
 233        sect_name, buf, size);
 234   xfree (buf);
 235
 236   if (data->note_data == NULL)
 237     data->abort_iteration = 1;
 238 }
 239
 240 /* Records the thread's register state for the corefile note
 241    section.  */
 242
 243 static char *
 244 fbsd_collect_thread_registers (const struct regcache *regcache,
 245                                ptid_t ptid, bfd *obfd,
 246                                char *note_data, int *note_size,
 247                                enum gdb_signal stop_signal)
 248 {
 249   struct gdbarch *gdbarch = regcache->arch ();
 250   struct fbsd_collect_regset_section_cb_data data;
 251
 252   data.regcache = regcache;
 253   data.obfd = obfd;
 254   data.note_data = note_data;
 255   data.note_size = note_size;
 256   data.stop_signal = stop_signal;
 257   data.abort_iteration = 0;
 258   data.lwp = ptid_get_lwp (ptid);
 259
 260   gdbarch_iterate_over_regset_sections (gdbarch,
 261                                         fbsd_collect_regset_section_cb,
 262                                         &data, regcache);
 263   return data.note_data;
 264 }
 265
 266 struct fbsd_corefile_thread_data
 267 {
 268   struct gdbarch *gdbarch;
 269   bfd *obfd;
 270   char *note_data;
 271   int *note_size;
 272   enum gdb_signal stop_signal;
 273 };
 274
 275 /* Records the thread's register state for the corefile note
 276    section.  */
 277
 278 static void
 279 fbsd_corefile_thread (struct thread_info *info,
 280                       struct fbsd_corefile_thread_data *args)
 281 {
 282   struct regcache *regcache;
 283
 284   regcache = get_thread_arch_regcache (info->ptid, args->gdbarch);
 285
 286   target_fetch_registers (regcache, -1);
 287
 288   args->note_data = fbsd_collect_thread_registers
 289     (regcache, info->ptid, args->obfd, args->note_data,
 290      args->note_size, args->stop_signal);
 291 }
 292
 293 /* Create appropriate note sections for a corefile, returning them in
 294    allocated memory.  */
 295
 296 static char *
 297 fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 298 {
 299   struct fbsd_corefile_thread_data thread_args;
 300   char *note_data = NULL;
 301   Elf_Internal_Ehdr *i_ehdrp;
 302   struct thread_info *curr_thr, *signalled_thr, *thr;
 303
 304   /* Put a "FreeBSD" label in the ELF header.  */
 305   i_ehdrp = elf_elfheader (obfd);
 306   i_ehdrp->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
 307
 308   gdb_assert (gdbarch_iterate_over_regset_sections_p (gdbarch));
 309
 310   if (get_exec_file (0))
 311     {
 312       const char *fname = lbasename (get_exec_file (0));
 313       char *psargs = xstrdup (fname);
 314
 315       if (get_inferior_args ())
 316         psargs = reconcat (psargs, psargs, " ", get_inferior_args (),
 317                            (char *) NULL);
 318
 319       note_data = elfcore_write_prpsinfo (obfd, note_data, note_size,
 320                                           fname, psargs);
 321     }
 322
 323   /* Thread register information.  */
 324   TRY
 325     {
 326       update_thread_list ();
 327     }
 328   CATCH (e, RETURN_MASK_ERROR)
 329     {
 330       exception_print (gdb_stderr, e);
 331     }
 332   END_CATCH
 333
 334   /* Like the kernel, prefer dumping the signalled thread first.
 335      "First thread" is what tools use to infer the signalled thread.
 336      In case there's more than one signalled thread, prefer the
 337      current thread, if it is signalled.  */
 338   curr_thr = inferior_thread ();
 339   if (curr_thr->suspend.stop_signal != GDB_SIGNAL_0)
 340     signalled_thr = curr_thr;
 341   else
 342     {
 343       signalled_thr = iterate_over_threads (find_signalled_thread, NULL);
 344       if (signalled_thr == NULL)
 345         signalled_thr = curr_thr;
 346     }
 347
 348   thread_args.gdbarch = gdbarch;
 349   thread_args.obfd = obfd;
 350   thread_args.note_data = note_data;
 351   thread_args.note_size = note_size;
 352   thread_args.stop_signal = signalled_thr->suspend.stop_signal;
 353
 354   fbsd_corefile_thread (signalled_thr, &thread_args);
 355   ALL_NON_EXITED_THREADS (thr)
 356     {
 357       if (thr == signalled_thr)
 358         continue;
 359       if (ptid_get_pid (thr->ptid) != ptid_get_pid (inferior_ptid))
 360         continue;
 361
 362       fbsd_corefile_thread (thr, &thread_args);
 363     }
 364
 365   note_data = thread_args.note_data;
 366
 367   return note_data;
 368 }
 369
 370 /* Print descriptions of FreeBSD-specific AUXV entries to FILE.  */
 371
 372 static void
 373 fbsd_print_auxv_entry (struct gdbarch *gdbarch, struct ui_file *file,
 374                        CORE_ADDR type, CORE_ADDR val)
 375 {
 376   const char *name;
 377   const char *description;
 378   enum auxv_format format;
 379
 380   switch (type)
 381     {
 382 #define _TAGNAME(tag) #tag
 383 #define TAGNAME(tag) _TAGNAME(AT_##tag)
 384 #define TAG(tag, text, kind) \
 385       case AT_FREEBSD_##tag: name = TAGNAME(tag); description = text; format = kind; break
 386       TAG (EXECPATH, _("Executable path"), AUXV_FORMAT_STR);
 387       TAG (CANARY, _("Canary for SSP"), AUXV_FORMAT_HEX);
 388       TAG (CANARYLEN, ("Length of the SSP canary"), AUXV_FORMAT_DEC);
 389       TAG (OSRELDATE, _("OSRELDATE"), AUXV_FORMAT_DEC);
 390       TAG (NCPUS, _("Number of CPUs"), AUXV_FORMAT_DEC);
 391       TAG (PAGESIZES, _("Pagesizes"), AUXV_FORMAT_HEX);
 392       TAG (PAGESIZESLEN, _("Number of pagesizes"), AUXV_FORMAT_DEC);
 393       TAG (TIMEKEEP, _("Pointer to timehands"), AUXV_FORMAT_HEX);
 394       TAG (STACKPROT, _("Initial stack protection"), AUXV_FORMAT_HEX);
 395       TAG (EHDRFLAGS, _("ELF header e_flags"), AUXV_FORMAT_HEX);
 396       TAG (HWCAP, _("Machine-dependent CPU capability hints"), AUXV_FORMAT_HEX);
 397     default:
 398       default_print_auxv_entry (gdbarch, file, type, val);
 399       return;
 400     }
 401
 402   fprint_auxv_entry (file, name, description, format, type, val);
 403 }
 404
 405 /* Implement the "get_siginfo_type" gdbarch method.  */
 406
 407 static struct type *
 408 fbsd_get_siginfo_type (struct gdbarch *gdbarch)
 409 {
 410   struct fbsd_gdbarch_data *fbsd_gdbarch_data;
 411   struct type *int_type, *int32_type, *uint32_type, *long_type, *void_ptr_type;
 412   struct type *uid_type, *pid_type;
 413   struct type *sigval_type, *reason_type;
 414   struct type *siginfo_type;
 415   struct type *type;
 416
 417   fbsd_gdbarch_data = get_fbsd_gdbarch_data (gdbarch);
 418   if (fbsd_gdbarch_data->siginfo_type != NULL)
 419     return fbsd_gdbarch_data->siginfo_type;
 420
 421   int_type = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch),
 422                                 0, "int");
 423   int32_type = arch_integer_type (gdbarch, 32, 0, "int32_t");
 424   uint32_type = arch_integer_type (gdbarch, 32, 1, "uint32_t");
 425   long_type = arch_integer_type (gdbarch, gdbarch_long_bit (gdbarch),
 426                                  0, "long");
 427   void_ptr_type = lookup_pointer_type (builtin_type (gdbarch)->builtin_void);
 428
 429   /* union sigval */
 430   sigval_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_UNION);
 431   TYPE_NAME (sigval_type) = xstrdup ("sigval");
 432   append_composite_type_field (sigval_type, "sival_int", int_type);
 433   append_composite_type_field (sigval_type, "sival_ptr", void_ptr_type);
 434
 435   /* __pid_t */
 436   pid_type = arch_type (gdbarch, TYPE_CODE_TYPEDEF,
 437                         TYPE_LENGTH (int32_type) * TARGET_CHAR_BIT, "__pid_t");
 438   TYPE_TARGET_TYPE (pid_type) = int32_type;
 439   TYPE_TARGET_STUB (pid_type) = 1;
 440
 441   /* __uid_t */
 442   uid_type = arch_type (gdbarch, TYPE_CODE_TYPEDEF,
 443                         TYPE_LENGTH (uint32_type) * TARGET_CHAR_BIT,
 444                         "__uid_t");
 445   TYPE_TARGET_TYPE (uid_type) = uint32_type;
 446   TYPE_TARGET_STUB (uid_type) = 1;
 447
 448   /* _reason */
 449   reason_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_UNION);
 450
 451   /* _fault */
 452   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 453   append_composite_type_field (type, "si_trapno", int_type);
 454   append_composite_type_field (reason_type, "_fault", type);
 455
 456   /* _timer */
 457   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 458   append_composite_type_field (type, "si_timerid", int_type);
 459   append_composite_type_field (type, "si_overrun", int_type);
 460   append_composite_type_field (reason_type, "_timer", type);
 461
 462   /* _mesgq */
 463   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 464   append_composite_type_field (type, "si_mqd", int_type);
 465   append_composite_type_field (reason_type, "_mesgq", type);
 466
 467   /* _poll */
 468   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 469   append_composite_type_field (type, "si_band", long_type);
 470   append_composite_type_field (reason_type, "_poll", type);
 471
 472   /* __spare__ */
 473   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 474   append_composite_type_field (type, "__spare1__", long_type);
 475   append_composite_type_field (type, "__spare2__",
 476                                init_vector_type (int_type, 7));
 477   append_composite_type_field (reason_type, "__spare__", type);
 478
 479   /* struct siginfo */
 480   siginfo_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 481   TYPE_NAME (siginfo_type) = xstrdup ("siginfo");
 482   append_composite_type_field (siginfo_type, "si_signo", int_type);
 483   append_composite_type_field (siginfo_type, "si_errno", int_type);
 484   append_composite_type_field (siginfo_type, "si_code", int_type);
 485   append_composite_type_field (siginfo_type, "si_pid", pid_type);
 486   append_composite_type_field (siginfo_type, "si_uid", uid_type);
 487   append_composite_type_field (siginfo_type, "si_status", int_type);
 488   append_composite_type_field (siginfo_type, "si_addr", void_ptr_type);
 489   append_composite_type_field (siginfo_type, "si_value", sigval_type);
 490   append_composite_type_field (siginfo_type, "_reason", reason_type);
 491
 492   fbsd_gdbarch_data->siginfo_type = siginfo_type;
 493
 494   return siginfo_type;
 495 }
 496
 497 /* Implement the "get_syscall_number" gdbarch method.  */
 498
 499 static LONGEST
 500 fbsd_get_syscall_number (struct gdbarch *gdbarch,
 501                          ptid_t ptid)
 502 {
 503
 504   /* FreeBSD doesn't use gdbarch_get_syscall_number since FreeBSD
 505      native targets fetch the system call number from the
 506      'pl_syscall_code' member of struct ptrace_lwpinfo in fbsd_wait.
 507      However, system call catching requires this function to be
 508      set.  */
 509
 510   internal_error (__FILE__, __LINE__, _("fbsd_get_sycall_number called"));
 511 }
 512
 513 /* To be called from GDB_OSABI_FREEBSD handlers. */
 514
 515 void
 516 fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 517 {
 518   set_gdbarch_core_pid_to_str (gdbarch, fbsd_core_pid_to_str);
 519   set_gdbarch_core_thread_name (gdbarch, fbsd_core_thread_name);
 520   set_gdbarch_core_xfer_siginfo (gdbarch, fbsd_core_xfer_siginfo);
 521   set_gdbarch_make_corefile_notes (gdbarch, fbsd_make_corefile_notes);
 522   set_gdbarch_print_auxv_entry (gdbarch, fbsd_print_auxv_entry);
 523   set_gdbarch_get_siginfo_type (gdbarch, fbsd_get_siginfo_type);
 524
 525   /* `catch syscall' */
 526   set_xml_syscall_file_name (gdbarch, "syscalls/freebsd.xml");
 527   set_gdbarch_get_syscall_number (gdbarch, fbsd_get_syscall_number);
 528 }
 529
 530 void
 531 _initialize_fbsd_tdep (void)
 532 {
 533   fbsd_gdbarch_data_handle =
 534     gdbarch_data_register_post_init (init_fbsd_gdbarch_data);
 535 }