gdb/dtrace-probe.c

   1 /* DTrace probe support for GDB.
   2
   3    Copyright (C) 2014-2016 Free Software Foundation, Inc.
   4
   5    Contributed by Oracle, 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 3 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, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "probe.h"
  24 #include "vec.h"
  25 #include "elf-bfd.h"
  26 #include "gdbtypes.h"
  27 #include "obstack.h"
  28 #include "objfiles.h"
  29 #include "complaints.h"
  30 #include "value.h"
  31 #include "ax.h"
  32 #include "ax-gdb.h"
  33 #include "language.h"
  34 #include "parser-defs.h"
  35 #include "inferior.h"
  36
  37 /* The type of the ELF sections where we will find the DOF programs
  38    with information about probes.  */
  39
  40 #ifndef SHT_SUNW_dof
  41 # define SHT_SUNW_dof   0x6ffffff4
  42 #endif
  43
  44 /* Forward declaration.  */
  45
  46 extern const struct probe_ops dtrace_probe_ops;
  47
  48 /* The following structure represents a single argument for the
  49    probe.  */
  50
  51 struct dtrace_probe_arg
  52 {
  53   /* The type of the probe argument.  */
  54   struct type *type;
  55
  56   /* A string describing the type.  */
  57   char *type_str;
  58
  59   /* The argument converted to an internal GDB expression.  */
  60   struct expression *expr;
  61 };
  62
  63 typedef struct dtrace_probe_arg dtrace_probe_arg_s;
  64 DEF_VEC_O (dtrace_probe_arg_s);
  65
  66 /* The following structure represents an enabler for a probe.  */
  67
  68 struct dtrace_probe_enabler
  69 {
  70   /* Program counter where the is-enabled probe is installed.  The
  71      contents (nops, whatever...) stored at this address are
  72      architecture dependent.  */
  73   CORE_ADDR address;
  74 };
  75
  76 typedef struct dtrace_probe_enabler dtrace_probe_enabler_s;
  77 DEF_VEC_O (dtrace_probe_enabler_s);
  78
  79 /* The following structure represents a dtrace probe.  */
  80
  81 struct dtrace_probe
  82 {
  83   /* Generic information about the probe.  This must be the first
  84      element of this struct, in order to maintain binary compatibility
  85      with the `struct probe' and be able to fully abstract it.  */
  86   struct probe p;
  87
  88   /* A probe can have zero or more arguments.  */
  89   int probe_argc;
  90   VEC (dtrace_probe_arg_s) *args;
  91
  92   /* A probe can have zero or more "enablers" associated with it.  */
  93   VEC (dtrace_probe_enabler_s) *enablers;
  94
  95   /* Whether the expressions for the arguments have been built.  */
  96   unsigned int args_expr_built : 1;
  97 };
  98
  99 /* Implementation of the probe_is_linespec method.  */
 100
 101 static int
 102 dtrace_probe_is_linespec (const char **linespecp)
 103 {
 104   static const char *const keywords[] = { "-pdtrace", "-probe-dtrace", NULL };
 105
 106   return probe_is_linespec_by_keyword (linespecp, keywords);
 107 }
 108
 109 /* DOF programs can contain an arbitrary number of sections of 26
 110    different types.  In order to support DTrace USDT probes we only
 111    need to handle a subset of these section types, fortunately.  These
 112    section types are defined in the following enumeration.
 113
 114    See linux/dtrace/dof_defines.h for a complete list of section types
 115    along with their values.  */
 116
 117 enum dtrace_dof_sect_type
 118 {
 119   /* Null section.  */
 120   DTRACE_DOF_SECT_TYPE_NONE = 0,
 121   /* A dof_ecbdesc_t. */
 122   DTRACE_DOF_SECT_TYPE_ECBDESC = 3,
 123   /* A string table.  */
 124   DTRACE_DOF_SECT_TYPE_STRTAB = 8,
 125   /* A dof_provider_t  */
 126   DTRACE_DOF_SECT_TYPE_PROVIDER = 15,
 127   /* Array of dof_probe_t  */
 128   DTRACE_DOF_SECT_TYPE_PROBES = 16,
 129   /* An array of probe arg mappings.  */
 130   DTRACE_DOF_SECT_TYPE_PRARGS = 17,
 131   /* An array of probe arg offsets.  */
 132   DTRACE_DOF_SECT_TYPE_PROFFS = 18,
 133   /* An array of probe is-enabled offsets.  */
 134   DTRACE_DOF_SECT_TYPE_PRENOFFS = 26
 135 };
 136
 137 /* The following collection of data structures map the structure of
 138    DOF entities.  Again, we only cover the subset of DOF used to
 139    implement USDT probes.
 140
 141    See linux/dtrace/dof.h header for a complete list of data
 142    structures.  */
 143
 144 /* Offsets to index the dofh_ident[] array defined below.  */
 145
 146 enum dtrace_dof_ident
 147 {
 148   /* First byte of the magic number.  */
 149   DTRACE_DOF_ID_MAG0 = 0,
 150   /* Second byte of the magic number.  */
 151   DTRACE_DOF_ID_MAG1 = 1,
 152   /* Third byte of the magic number.  */
 153   DTRACE_DOF_ID_MAG2 = 2,
 154   /* Fourth byte of the magic number.  */
 155   DTRACE_DOF_ID_MAG3 = 3,
 156   /* An enum_dof_encoding value.  */
 157   DTRACE_DOF_ID_ENCODING = 5
 158 };
 159
 160 /* Possible values for dofh_ident[DOF_ID_ENCODING].  */
 161
 162 enum dtrace_dof_encoding
 163 {
 164   /* The DOF program is little-endian.  */
 165   DTRACE_DOF_ENCODE_LSB = 1,
 166   /* The DOF program is big-endian.  */
 167   DTRACE_DOF_ENCODE_MSB = 2
 168 };
 169
 170 /* A DOF header, which describes the contents of a DOF program: number
 171    of sections, size, etc.  */
 172
 173 struct dtrace_dof_hdr
 174 {
 175   /* Identification bytes (see above). */
 176   uint8_t dofh_ident[16];
 177   /* File attribute flags (if any). */
 178   uint32_t dofh_flags;
 179   /* Size of file header in bytes. */
 180   uint32_t dofh_hdrsize;
 181   /* Size of section header in bytes. */
 182   uint32_t dofh_secsize;
 183   /* Number of section headers. */
 184   uint32_t dofh_secnum;
 185   /* File offset of section headers. */
 186   uint64_t dofh_secoff;
 187   /* File size of loadable portion. */
 188   uint64_t dofh_loadsz;
 189   /* File size of entire DOF file. */
 190   uint64_t dofh_filesz;
 191   /* Reserved for future use. */
 192   uint64_t dofh_pad;
 193 };
 194
 195 /* A DOF section, whose contents depend on its type.  The several
 196    supported section types are described in the enum
 197    dtrace_dof_sect_type above.  */
 198
 199 struct dtrace_dof_sect
 200 {
 201   /* Section type (see the define above). */
 202   uint32_t dofs_type;
 203   /* Section data memory alignment. */
 204   uint32_t dofs_align;
 205   /* Section flags (if any). */
 206   uint32_t dofs_flags;
 207   /* Size of section entry (if table). */
 208   uint32_t dofs_entsize;
 209   /* DOF + offset points to the section data. */
 210   uint64_t dofs_offset;
 211   /* Size of section data in bytes.  */
 212   uint64_t dofs_size;
 213 };
 214
 215 /* A DOF provider, which is the provider of a probe.  */
 216
 217 struct dtrace_dof_provider
 218 {
 219   /* Link to a DTRACE_DOF_SECT_TYPE_STRTAB section. */
 220   uint32_t dofpv_strtab;
 221   /* Link to a DTRACE_DOF_SECT_TYPE_PROBES section. */
 222   uint32_t dofpv_probes;
 223   /* Link to a DTRACE_DOF_SECT_TYPE_PRARGS section. */
 224   uint32_t dofpv_prargs;
 225   /* Link to a DTRACE_DOF_SECT_TYPE_PROFFS section. */
 226   uint32_t dofpv_proffs;
 227   /* Provider name string. */
 228   uint32_t dofpv_name;
 229   /* Provider attributes. */
 230   uint32_t dofpv_provattr;
 231   /* Module attributes. */
 232   uint32_t dofpv_modattr;
 233   /* Function attributes. */
 234   uint32_t dofpv_funcattr;
 235   /* Name attributes. */
 236   uint32_t dofpv_nameattr;
 237   /* Args attributes. */
 238   uint32_t dofpv_argsattr;
 239   /* Link to a DTRACE_DOF_SECT_PRENOFFS section. */
 240   uint32_t dofpv_prenoffs;
 241 };
 242
 243 /* A set of DOF probes and is-enabled probes sharing a base address
 244    and several attributes.  The particular locations and attributes of
 245    each probe are maintained in arrays in several other DOF sections.
 246    See the comment in dtrace_process_dof_probe for details on how
 247    these attributes are stored.  */
 248
 249 struct dtrace_dof_probe
 250 {
 251   /* Probe base address or offset. */
 252   uint64_t dofpr_addr;
 253   /* Probe function string. */
 254   uint32_t dofpr_func;
 255   /* Probe name string. */
 256   uint32_t dofpr_name;
 257   /* Native argument type strings. */
 258   uint32_t dofpr_nargv;
 259   /* Translated argument type strings. */
 260   uint32_t dofpr_xargv;
 261   /* Index of first argument mapping. */
 262   uint32_t dofpr_argidx;
 263   /* Index of first offset entry. */
 264   uint32_t dofpr_offidx;
 265   /* Native argument count. */
 266   uint8_t  dofpr_nargc;
 267   /* Translated argument count. */
 268   uint8_t  dofpr_xargc;
 269   /* Number of offset entries for probe. */
 270   uint16_t dofpr_noffs;
 271   /* Index of first is-enabled offset. */
 272   uint32_t dofpr_enoffidx;
 273   /* Number of is-enabled offsets. */
 274   uint16_t dofpr_nenoffs;
 275   /* Reserved for future use. */
 276   uint16_t dofpr_pad1;
 277   /* Reserved for future use. */
 278   uint32_t dofpr_pad2;
 279 };
 280
 281 /* DOF supports two different encodings: MSB (big-endian) and LSB
 282    (little-endian).  The encoding is itself encoded in the DOF header.
 283    The following function returns an unsigned value in the host
 284    endianness.  */
 285
 286 #define DOF_UINT(dof, field)                                            \
 287   extract_unsigned_integer ((gdb_byte *) &(field),                      \
 288                             sizeof ((field)),                           \
 289                             (((dof)->dofh_ident[DTRACE_DOF_ID_ENCODING] \
 290                               == DTRACE_DOF_ENCODE_MSB)                 \
 291                              ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE))
 292
 293 /* The following macro applies a given byte offset to a DOF (a pointer
 294    to a dtrace_dof_hdr structure) and returns the resulting
 295    address.  */
 296
 297 #define DTRACE_DOF_PTR(dof, offset) (&((char *) (dof))[(offset)])
 298
 299 /* The following macro returns a pointer to the beginning of a given
 300    section in a DOF object.  The section is referred to by its index
 301    in the sections array.  */
 302
 303 #define DTRACE_DOF_SECT(dof, idx)                                       \
 304   ((struct dtrace_dof_sect *)                                           \
 305    DTRACE_DOF_PTR ((dof),                                               \
 306                    DOF_UINT ((dof), (dof)->dofh_secoff)                 \
 307                    + ((idx) * DOF_UINT ((dof), (dof)->dofh_secsize))))
 308
 309 /* Helper function to examine the probe described by the given PROBE
 310    and PROVIDER data structures and add it to the PROBESP vector.
 311    STRTAB, OFFTAB, EOFFTAB and ARGTAB are pointers to tables in the
 312    DOF program containing the attributes for the probe.  */
 313
 314 static void
 315 dtrace_process_dof_probe (struct objfile *objfile,
 316                           struct gdbarch *gdbarch, VEC (probe_p) **probesp,
 317                           struct dtrace_dof_hdr *dof,
 318                           struct dtrace_dof_probe *probe,
 319                           struct dtrace_dof_provider *provider,
 320                           char *strtab, char *offtab, char *eofftab,
 321                           char *argtab, uint64_t strtab_size)
 322 {
 323   int i, j, num_probes, num_enablers;
 324   struct cleanup *cleanup;
 325   VEC (dtrace_probe_enabler_s) *enablers;
 326   char *p;
 327
 328   /* Each probe section can define zero or more probes of two
 329      different types:
 330
 331      - probe->dofpr_noffs regular probes whose program counters are
 332        stored in 32bit words starting at probe->dofpr_addr +
 333        offtab[probe->dofpr_offidx].
 334
 335      - probe->dofpr_nenoffs is-enabled probes whose program counters
 336        are stored in 32bit words starting at probe->dofpr_addr +
 337        eofftab[probe->dofpr_enoffidx].
 338
 339      However is-enabled probes are not probes per-se, but an
 340      optimization hack that is implemented in the kernel in a very
 341      similar way than normal probes.  This is how we support
 342      is-enabled probes on GDB:
 343
 344      - Our probes are always DTrace regular probes.
 345
 346      - Our probes can be associated with zero or more "enablers".  The
 347        list of enablers is built from the is-enabled probes defined in
 348        the Probe section.
 349
 350      - Probes having a non-empty list of enablers can be enabled or
 351        disabled using the `enable probe' and `disable probe' commands
 352        respectively.  The `Enabled' column in the output of `info
 353        probes' will read `yes' if the enablers are activated, `no'
 354        otherwise.
 355
 356      - Probes having an empty list of enablers are always enabled.
 357        The `Enabled' column in the output of `info probes' will
 358        read `always'.
 359
 360      It follows that if there are DTrace is-enabled probes defined for
 361      some provider/name but no DTrace regular probes defined then the
 362      GDB user wont be able to enable/disable these conditionals.  */
 363
 364   num_probes = DOF_UINT (dof, probe->dofpr_noffs);
 365   if (num_probes == 0)
 366     return;
 367
 368   /* Build the list of enablers for the probes defined in this Probe
 369      DOF section.  */
 370   enablers = NULL;
 371   cleanup
 372     = make_cleanup (VEC_cleanup (dtrace_probe_enabler_s), &enablers);
 373   num_enablers = DOF_UINT (dof, probe->dofpr_nenoffs);
 374   for (i = 0; i < num_enablers; i++)
 375     {
 376       struct dtrace_probe_enabler enabler;
 377       uint32_t enabler_offset
 378         = ((uint32_t *) eofftab)[DOF_UINT (dof, probe->dofpr_enoffidx) + i];
 379
 380       enabler.address = DOF_UINT (dof, probe->dofpr_addr)
 381         + DOF_UINT (dof, enabler_offset);
 382       VEC_safe_push (dtrace_probe_enabler_s, enablers, &enabler);
 383     }
 384
 385   for (i = 0; i < num_probes; i++)
 386     {
 387       uint32_t probe_offset
 388         = ((uint32_t *) offtab)[DOF_UINT (dof, probe->dofpr_offidx) + i];
 389       struct dtrace_probe *ret =
 390         XOBNEW (&objfile->per_bfd->storage_obstack, struct dtrace_probe);
 391
 392       ret->p.pops = &dtrace_probe_ops;
 393       ret->p.arch = gdbarch;
 394       ret->args_expr_built = 0;
 395
 396       /* Set the provider and the name of the probe.  */
 397       ret->p.provider
 398         = xstrdup (strtab + DOF_UINT (dof, provider->dofpv_name));
 399       ret->p.name = xstrdup (strtab + DOF_UINT (dof, probe->dofpr_name));
 400
 401       /* The probe address.  */
 402       ret->p.address
 403         = DOF_UINT (dof, probe->dofpr_addr) + DOF_UINT (dof, probe_offset);
 404
 405       /* Number of arguments in the probe.  */
 406       ret->probe_argc = DOF_UINT (dof, probe->dofpr_nargc);
 407
 408       /* Store argument type descriptions.  A description of the type
 409          of the argument is in the (J+1)th null-terminated string
 410          starting at 'strtab' + 'probe->dofpr_nargv'.  */
 411       ret->args = NULL;
 412       p = strtab + DOF_UINT (dof, probe->dofpr_nargv);
 413       for (j = 0; j < ret->probe_argc; j++)
 414         {
 415           struct dtrace_probe_arg arg;
 416           expression_up expr;
 417
 418           /* Set arg.expr to ensure all fields in expr are initialized and
 419              the compiler will not warn when arg is used.  */
 420           arg.expr = NULL;
 421           arg.type_str = xstrdup (p);
 422
 423           /* Use strtab_size as a sentinel.  */
 424           while (*p++ != '\0' && p - strtab < strtab_size);
 425
 426           /* Try to parse a type expression from the type string.  If
 427              this does not work then we set the type to `long
 428              int'.  */
 429           arg.type = builtin_type (gdbarch)->builtin_long;
 430
 431           TRY
 432             {
 433               expr = parse_expression_with_language (arg.type_str, language_c);
 434             }
 435           CATCH (ex, RETURN_MASK_ERROR)
 436             {
 437             }
 438           END_CATCH
 439
 440           if (expr != NULL && expr->elts[0].opcode == OP_TYPE)
 441             arg.type = expr->elts[1].type;
 442
 443           VEC_safe_push (dtrace_probe_arg_s, ret->args, &arg);
 444         }
 445
 446       /* Add the vector of enablers to this probe, if any.  */
 447       ret->enablers = VEC_copy (dtrace_probe_enabler_s, enablers);
 448
 449       /* Successfully created probe.  */
 450       VEC_safe_push (probe_p, *probesp, (struct probe *) ret);
 451     }
 452
 453   do_cleanups (cleanup);
 454 }
 455
 456 /* Helper function to collect the probes described in the DOF program
 457    whose header is pointed by DOF and add them to the PROBESP vector.
 458    SECT is the ELF section containing the DOF program and OBJFILE is
 459    its containing object file.  */
 460
 461 static void
 462 dtrace_process_dof (asection *sect, struct objfile *objfile,
 463                     VEC (probe_p) **probesp, struct dtrace_dof_hdr *dof)
 464 {
 465   struct gdbarch *gdbarch = get_objfile_arch (objfile);
 466   struct dtrace_dof_sect *section;
 467   int i;
 468
 469   /* The first step is to check for the DOF magic number.  If no valid
 470      DOF data is found in the section then a complaint is issued to
 471      the user and the section skipped.  */
 472   if (dof->dofh_ident[DTRACE_DOF_ID_MAG0] != 0x7F
 473       || dof->dofh_ident[DTRACE_DOF_ID_MAG1] != 'D'
 474       || dof->dofh_ident[DTRACE_DOF_ID_MAG2] != 'O'
 475       || dof->dofh_ident[DTRACE_DOF_ID_MAG3] != 'F')
 476     goto invalid_dof_data;
 477
 478   /* Make sure the encoding mark is either DTRACE_DOF_ENCODE_LSB or
 479      DTRACE_DOF_ENCODE_MSB.  */
 480   if (dof->dofh_ident[DTRACE_DOF_ID_ENCODING] != DTRACE_DOF_ENCODE_LSB
 481       && dof->dofh_ident[DTRACE_DOF_ID_ENCODING] != DTRACE_DOF_ENCODE_MSB)
 482     goto invalid_dof_data;
 483
 484   /* Make sure this DOF is not an enabling DOF, i.e. there are no ECB
 485      Description sections.  */
 486   section = (struct dtrace_dof_sect *) DTRACE_DOF_PTR (dof,
 487                                                        DOF_UINT (dof, dof->dofh_secoff));
 488   for (i = 0; i < DOF_UINT (dof, dof->dofh_secnum); i++, section++)
 489     if (section->dofs_type == DTRACE_DOF_SECT_TYPE_ECBDESC)
 490       return;
 491
 492   /* Iterate over any section of type Provider and extract the probe
 493      information from them.  If there are no "provider" sections on
 494      the DOF then we just return.  */
 495   section = (struct dtrace_dof_sect *) DTRACE_DOF_PTR (dof,
 496                                                        DOF_UINT (dof, dof->dofh_secoff));
 497   for (i = 0; i < DOF_UINT (dof, dof->dofh_secnum); i++, section++)
 498     if (DOF_UINT (dof, section->dofs_type) == DTRACE_DOF_SECT_TYPE_PROVIDER)
 499       {
 500         struct dtrace_dof_provider *provider = (struct dtrace_dof_provider *)
 501           DTRACE_DOF_PTR (dof, DOF_UINT (dof, section->dofs_offset));
 502         struct dtrace_dof_sect *strtab_s
 503           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_strtab));
 504         struct dtrace_dof_sect *probes_s
 505           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_probes));
 506         struct dtrace_dof_sect *args_s
 507           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_prargs));
 508         struct dtrace_dof_sect *offsets_s
 509           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_proffs));
 510         struct dtrace_dof_sect *eoffsets_s
 511           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_prenoffs));
 512         char *strtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, strtab_s->dofs_offset));
 513         char *offtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, offsets_s->dofs_offset));
 514         char *eofftab = DTRACE_DOF_PTR (dof, DOF_UINT (dof, eoffsets_s->dofs_offset));
 515         char *argtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, args_s->dofs_offset));
 516         unsigned int entsize = DOF_UINT (dof, probes_s->dofs_entsize);
 517         int num_probes;
 518
 519         if (DOF_UINT (dof, section->dofs_size)
 520             < sizeof (struct dtrace_dof_provider))
 521           {
 522             /* The section is smaller than expected, so do not use it.
 523                This has been observed on x86-solaris 10.  */
 524             goto invalid_dof_data;
 525           }
 526
 527         /* Very, unlikely, but could crash gdb if not handled
 528            properly.  */
 529         if (entsize == 0)
 530           goto invalid_dof_data;
 531
 532         num_probes = DOF_UINT (dof, probes_s->dofs_size) / entsize;
 533
 534         for (i = 0; i < num_probes; i++)
 535           {
 536             struct dtrace_dof_probe *probe = (struct dtrace_dof_probe *)
 537               DTRACE_DOF_PTR (dof, DOF_UINT (dof, probes_s->dofs_offset)
 538                               + (i * DOF_UINT (dof, probes_s->dofs_entsize)));
 539
 540             dtrace_process_dof_probe (objfile,
 541                                       gdbarch, probesp,
 542                                       dof, probe,
 543                                       provider, strtab, offtab, eofftab, argtab,
 544                                       DOF_UINT (dof, strtab_s->dofs_size));
 545           }
 546       }
 547
 548   return;
 549
 550  invalid_dof_data:
 551   complaint (&symfile_complaints,
 552              _("skipping section '%s' which does not contain valid DOF data."),
 553              sect->name);
 554 }
 555
 556 /* Helper function to build the GDB internal expressiosn that, once
 557    evaluated, will calculate the values of the arguments of a given
 558    PROBE.  */
 559
 560 static void
 561 dtrace_build_arg_exprs (struct dtrace_probe *probe,
 562                         struct gdbarch *gdbarch)
 563 {
 564   struct parser_state pstate;
 565   struct dtrace_probe_arg *arg;
 566   int i;
 567
 568   probe->args_expr_built = 1;
 569
 570   /* Iterate over the arguments in the probe and build the
 571      corresponding GDB internal expression that will generate the
 572      value of the argument when executed at the PC of the probe.  */
 573   for (i = 0; i < probe->probe_argc; i++)
 574     {
 575       struct cleanup *back_to;
 576
 577       arg = VEC_index (dtrace_probe_arg_s, probe->args, i);
 578
 579       /* Initialize the expression buffer in the parser state.  The
 580          language does not matter, since we are using our own
 581          parser.  */
 582       initialize_expout (&pstate, 10, current_language, gdbarch);
 583       back_to = make_cleanup (free_current_contents, &pstate.expout);
 584
 585       /* The argument value, which is ABI dependent and casted to
 586          `long int'.  */
 587       gdbarch_dtrace_parse_probe_argument (gdbarch, &pstate, i);
 588
 589       discard_cleanups (back_to);
 590
 591       /* Casting to the expected type, but only if the type was
 592          recognized at probe load time.  Otherwise the argument will
 593          be evaluated as the long integer passed to the probe.  */
 594       if (arg->type != NULL)
 595         {
 596           write_exp_elt_opcode (&pstate, UNOP_CAST);
 597           write_exp_elt_type (&pstate, arg->type);
 598           write_exp_elt_opcode (&pstate, UNOP_CAST);
 599         }
 600
 601       reallocate_expout (&pstate);
 602       arg->expr = pstate.expout;
 603       prefixify_expression (arg->expr);
 604     }
 605 }
 606
 607 /* Helper function to return the Nth argument of a given PROBE.  */
 608
 609 static struct dtrace_probe_arg *
 610 dtrace_get_arg (struct dtrace_probe *probe, unsigned n,
 611                 struct gdbarch *gdbarch)
 612 {
 613   if (!probe->args_expr_built)
 614     dtrace_build_arg_exprs (probe, gdbarch);
 615
 616   return VEC_index (dtrace_probe_arg_s, probe->args, n);
 617 }
 618
 619 /* Implementation of the get_probes method.  */
 620
 621 static void
 622 dtrace_get_probes (VEC (probe_p) **probesp, struct objfile *objfile)
 623 {
 624   bfd *abfd = objfile->obfd;
 625   asection *sect = NULL;
 626
 627   /* Do nothing in case this is a .debug file, instead of the objfile
 628      itself.  */
 629   if (objfile->separate_debug_objfile_backlink != NULL)
 630     return;
 631
 632   /* Iterate over the sections in OBJFILE looking for DTrace
 633      information.  */
 634   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 635     {
 636       if (elf_section_data (sect)->this_hdr.sh_type == SHT_SUNW_dof)
 637         {
 638           bfd_byte *dof;
 639
 640           /* Read the contents of the DOF section and then process it to
 641              extract the information of any probe defined into it.  */
 642           if (!bfd_malloc_and_get_section (abfd, sect, &dof))
 643             complaint (&symfile_complaints,
 644                        _("could not obtain the contents of"
 645                          "section '%s' in objfile `%s'."),
 646                        sect->name, abfd->filename);
 647
 648           dtrace_process_dof (sect, objfile, probesp,
 649                               (struct dtrace_dof_hdr *) dof);
 650           xfree (dof);
 651         }
 652     }
 653 }
 654
 655 /* Helper function to determine whether a given probe is "enabled" or
 656    "disabled".  A disabled probe is a probe in which one or more
 657    enablers are disabled.  */
 658
 659 static int
 660 dtrace_probe_is_enabled (struct dtrace_probe *probe)
 661 {
 662   int i;
 663   struct gdbarch *gdbarch = probe->p.arch;
 664   struct dtrace_probe_enabler *enabler;
 665
 666   for (i = 0;
 667        VEC_iterate (dtrace_probe_enabler_s, probe->enablers, i, enabler);
 668        i++)
 669     if (!gdbarch_dtrace_probe_is_enabled (gdbarch, enabler->address))
 670       return 0;
 671
 672   return 1;
 673 }
 674
 675 /* Implementation of the get_probe_address method.  */
 676
 677 static CORE_ADDR
 678 dtrace_get_probe_address (struct probe *probe, struct objfile *objfile)
 679 {
 680   gdb_assert (probe->pops == &dtrace_probe_ops);
 681   return probe->address + ANOFFSET (objfile->section_offsets,
 682                                     SECT_OFF_DATA (objfile));
 683 }
 684
 685 /* Implementation of the get_probe_argument_count method.  */
 686
 687 static unsigned
 688 dtrace_get_probe_argument_count (struct probe *probe_generic,
 689                                  struct frame_info *frame)
 690 {
 691   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 692
 693   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 694
 695   return dtrace_probe->probe_argc;
 696 }
 697
 698 /* Implementation of the can_evaluate_probe_arguments method.  */
 699
 700 static int
 701 dtrace_can_evaluate_probe_arguments (struct probe *probe_generic)
 702 {
 703   struct gdbarch *gdbarch = probe_generic->arch;
 704
 705   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 706   return gdbarch_dtrace_parse_probe_argument_p (gdbarch);
 707 }
 708
 709 /* Implementation of the evaluate_probe_argument method.  */
 710
 711 static struct value *
 712 dtrace_evaluate_probe_argument (struct probe *probe_generic, unsigned n,
 713                                 struct frame_info *frame)
 714 {
 715   struct gdbarch *gdbarch = probe_generic->arch;
 716   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 717   struct dtrace_probe_arg *arg;
 718   int pos = 0;
 719
 720   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 721
 722   arg = dtrace_get_arg (dtrace_probe, n, gdbarch);
 723   return evaluate_subexp_standard (arg->type, arg->expr, &pos, EVAL_NORMAL);
 724 }
 725
 726 /* Implementation of the compile_to_ax method.  */
 727
 728 static void
 729 dtrace_compile_to_ax (struct probe *probe_generic, struct agent_expr *expr,
 730                       struct axs_value *value, unsigned n)
 731 {
 732   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 733   struct dtrace_probe_arg *arg;
 734   union exp_element *pc;
 735
 736   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 737
 738   arg = dtrace_get_arg (dtrace_probe, n, expr->gdbarch);
 739
 740   pc = arg->expr->elts;
 741   gen_expr (arg->expr, &pc, expr, value);
 742
 743   require_rvalue (expr, value);
 744   value->type = arg->type;
 745 }
 746
 747 /* Implementation of the probe_destroy method.  */
 748
 749 static void
 750 dtrace_probe_destroy (struct probe *probe_generic)
 751 {
 752   struct dtrace_probe *probe = (struct dtrace_probe *) probe_generic;
 753   struct dtrace_probe_arg *arg;
 754   int i;
 755
 756   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 757
 758   for (i = 0; VEC_iterate (dtrace_probe_arg_s, probe->args, i, arg); i++)
 759     {
 760       xfree (arg->type_str);
 761       xfree (arg->expr);
 762     }
 763
 764   VEC_free (dtrace_probe_enabler_s, probe->enablers);
 765   VEC_free (dtrace_probe_arg_s, probe->args);
 766 }
 767
 768 /* Implementation of the type_name method.  */
 769
 770 static const char *
 771 dtrace_type_name (struct probe *probe_generic)
 772 {
 773   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 774   return "dtrace";
 775 }
 776
 777 /* Implementation of the gen_info_probes_table_header method.  */
 778
 779 static void
 780 dtrace_gen_info_probes_table_header (VEC (info_probe_column_s) **heads)
 781 {
 782   info_probe_column_s dtrace_probe_column;
 783
 784   dtrace_probe_column.field_name = "enabled";
 785   dtrace_probe_column.print_name = _("Enabled");
 786
 787   VEC_safe_push (info_probe_column_s, *heads, &dtrace_probe_column);
 788 }
 789
 790 /* Implementation of the gen_info_probes_table_values method.  */
 791
 792 static void
 793 dtrace_gen_info_probes_table_values (struct probe *probe_generic,
 794                                      VEC (const_char_ptr) **ret)
 795 {
 796   struct dtrace_probe *probe = (struct dtrace_probe *) probe_generic;
 797   const char *val = NULL;
 798
 799   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 800
 801   if (VEC_empty (dtrace_probe_enabler_s, probe->enablers))
 802     val = "always";
 803   else if (!gdbarch_dtrace_probe_is_enabled_p (probe_generic->arch))
 804     val = "unknown";
 805   else if (dtrace_probe_is_enabled (probe))
 806     val = "yes";
 807   else
 808     val = "no";
 809
 810   VEC_safe_push (const_char_ptr, *ret, val);
 811 }
 812
 813 /* Implementation of the enable_probe method.  */
 814
 815 static void
 816 dtrace_enable_probe (struct probe *probe)
 817 {
 818   struct gdbarch *gdbarch = probe->arch;
 819   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe;
 820   struct dtrace_probe_enabler *enabler;
 821   int i;
 822
 823   gdb_assert (probe->pops == &dtrace_probe_ops);
 824
 825   /* Enabling a dtrace probe implies patching the text section of the
 826      running process, so make sure the inferior is indeed running.  */
 827   if (ptid_equal (inferior_ptid, null_ptid))
 828     error (_("No inferior running"));
 829
 830   /* Fast path.  */
 831   if (dtrace_probe_is_enabled (dtrace_probe))
 832     return;
 833
 834   /* Iterate over all defined enabler in the given probe and enable
 835      them all using the corresponding gdbarch hook.  */
 836
 837   for (i = 0;
 838        VEC_iterate (dtrace_probe_enabler_s, dtrace_probe->enablers, i, enabler);
 839        i++)
 840     if (gdbarch_dtrace_enable_probe_p (gdbarch))
 841       gdbarch_dtrace_enable_probe (gdbarch, enabler->address);
 842 }
 843
 844
 845 /* Implementation of the disable_probe method.  */
 846
 847 static void
 848 dtrace_disable_probe (struct probe *probe)
 849 {
 850   struct gdbarch *gdbarch = probe->arch;
 851   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe;
 852   struct dtrace_probe_enabler *enabler;
 853   int i;
 854
 855   gdb_assert (probe->pops == &dtrace_probe_ops);
 856
 857   /* Disabling a dtrace probe implies patching the text section of the
 858      running process, so make sure the inferior is indeed running.  */
 859   if (ptid_equal (inferior_ptid, null_ptid))
 860     error (_("No inferior running"));
 861
 862   /* Fast path.  */
 863   if (!dtrace_probe_is_enabled (dtrace_probe))
 864     return;
 865
 866   /* Are we trying to disable a probe that does not have any enabler
 867      associated?  */
 868   if (VEC_empty (dtrace_probe_enabler_s, dtrace_probe->enablers))
 869     error (_("Probe %s:%s cannot be disabled: no enablers."), probe->provider, probe->name);
 870
 871   /* Iterate over all defined enabler in the given probe and disable
 872      them all using the corresponding gdbarch hook.  */
 873
 874   for (i = 0;
 875        VEC_iterate (dtrace_probe_enabler_s, dtrace_probe->enablers, i, enabler);
 876        i++)
 877     if (gdbarch_dtrace_disable_probe_p (gdbarch))
 878       gdbarch_dtrace_disable_probe (gdbarch, enabler->address);
 879 }
 880
 881 /* DTrace probe_ops.  */
 882
 883 const struct probe_ops dtrace_probe_ops =
 884 {
 885   dtrace_probe_is_linespec,
 886   dtrace_get_probes,
 887   dtrace_get_probe_address,
 888   dtrace_get_probe_argument_count,
 889   dtrace_can_evaluate_probe_arguments,
 890   dtrace_evaluate_probe_argument,
 891   dtrace_compile_to_ax,
 892   NULL, /* set_semaphore  */
 893   NULL, /* clear_semaphore  */
 894   dtrace_probe_destroy,
 895   dtrace_type_name,
 896   dtrace_gen_info_probes_table_header,
 897   dtrace_gen_info_probes_table_values,
 898   dtrace_enable_probe,
 899   dtrace_disable_probe
 900 };
 901
 902 /* Implementation of the `info probes dtrace' command.  */
 903
 904 static void
 905 info_probes_dtrace_command (char *arg, int from_tty)
 906 {
 907   info_probes_for_ops (arg, from_tty, &dtrace_probe_ops);
 908 }
 909
 910 void _initialize_dtrace_probe (void);
 911
 912 void
 913 _initialize_dtrace_probe (void)
 914 {
 915   VEC_safe_push (probe_ops_cp, all_probe_ops, &dtrace_probe_ops);
 916
 917   add_cmd ("dtrace", class_info, info_probes_dtrace_command,
 918            _("\
 919 Show information about DTrace static probes.\n\
 920 Usage: info probes dtrace [PROVIDER [NAME [OBJECT]]]\n\
 921 Each argument is a regular expression, used to select probes.\n\
 922 PROVIDER matches probe provider names.\n\
 923 NAME matches the probe names.\n\
 924 OBJECT matches the executable or shared library name."),
 925            info_probes_cmdlist_get ());
 926 }