/* Read and display shared object profiling data.

   Copyright (C) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <argp.h>

#include <dlfcn.h>

#include <elf.h>

#include <error.h>

#include <fcntl.h>

#include <inttypes.h>

#include <libintl.h>

#include <locale.h>

#include <obstack.h>

#include <search.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <stdint.h>

#include <ldsodefs.h>

#include <sys/gmon.h>

#include <sys/gmon_out.h>

#include <sys/mman.h>

#include <sys/param.h>

#include <sys/stat.h>

/* Get libc version number.  */

#include "../version.h"

#define PACKAGE _libc_intl_domainname

#include <endian.h>

#if BYTE_ORDER == BIG_ENDIAN

# define byteorder ELFDATA2MSB

# define byteorder_name "big-endian"

#elif BYTE_ORDER == LITTLE_ENDIAN

# define byteorder ELFDATA2LSB

# define byteorder_name "little-endian"

#else

# error "Unknown BYTE_ORDER " BYTE_ORDER

# define byteorder ELFDATANONE

#endif

#ifndef PATH_MAX

# define PATH_MAX 1024

#endif

extern int __profile_frequency (void);

/* Name and version of program.  */

static void print_version (FILE *stream, struct argp_state *state);

void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;

#define OPT_TEST	1

/* Definitions of arguments for argp functions.  */

static const struct argp_option options[] =

{

  { NULL, 0, NULL, 0, N_("Output selection:") },

  { "call-pairs", 'c', NULL, 0,

    N_("print list of count paths and their number of use") },

  { "flat-profile", 'p', NULL, 0,

    N_("generate flat profile with counts and ticks") },

  { "graph", 'q', NULL, 0, N_("generate call graph") },

  { "test", OPT_TEST, NULL, OPTION_HIDDEN, NULL },

  { NULL, 0, NULL, 0, NULL }

};

/* Short description of program.  */

static const char doc[] = N_("Read and display shared object profiling data.");

//For bug reporting instructions, please see:\n

//<http://www.gnu.org/software/libc/bugs.html>.\n");

/* Strings for arguments in help texts.  */

static const char args_doc[] = N_("SHOBJ [PROFDATA]");

/* Prototype for option handler.  */

static error_t parse_opt (int key, char *arg, struct argp_state *state);

/* Function to print some extra text in the help message.  */

static char *more_help (int key, const char *text, void *input);

/* Data structure to communicate with argp functions.  */

static struct argp argp =

{

  options, parse_opt, args_doc, doc, NULL, more_help

};

/* Operation modes.  */

static enum

{

  NONE = 0,

  FLAT_MODE = 1 << 0,

  CALL_GRAPH_MODE = 1 << 1,

  CALL_PAIRS = 1 << 2,

  DEFAULT_MODE = FLAT_MODE | CALL_GRAPH_MODE

} mode;

/* Nozero for testing.  */

static int do_test;

/* Strcuture describing calls.  */

struct here_fromstruct

{

  struct here_cg_arc_record volatile *here;

  uint16_t link;

};

/* We define a special type to address the elements of the arc table.

   This is basically the `gmon_cg_arc_record' format but it includes

   the room for the tag and it uses real types.  */

struct here_cg_arc_record

{

  uintptr_t from_pc;

  uintptr_t self_pc;

  uint32_t count;

} __attribute__ ((packed));

struct known_symbol;

struct arc_list

{

  size_t idx;

  uintmax_t count;

  struct arc_list *next;

};

static struct obstack ob_list;

struct known_symbol

{

  const char *name;

  uintptr_t addr;

  size_t size;

  bool weak;

  bool hidden;

  uintmax_t ticks;

  uintmax_t calls;

  struct arc_list *froms;

  struct arc_list *tos;

};

struct shobj

{

  const char *name;		/* User-provided name.  */

  struct link_map *map;

  const char *dynstrtab;	/* Dynamic string table of shared object.  */

  const char *soname;		/* Soname of shared object.  */

  uintptr_t lowpc;

  uintptr_t highpc;

  unsigned long int kcountsize;

  size_t expected_size;		/* Expected size of profiling file.  */

  size_t tossize;

  size_t fromssize;

  size_t fromlimit;

  unsigned int hashfraction;

  int s_scale;

  void *symbol_map;

  size_t symbol_mapsize;

  const ElfW(Sym) *symtab;

  size_t symtab_size;

  const char *strtab;

  struct obstack ob_str;

  struct obstack ob_sym;

};

struct real_gmon_hist_hdr

{

  char *low_pc;

  char *high_pc;

  int32_t hist_size;

  int32_t prof_rate;

  char dimen[15];

  char dimen_abbrev;

};

struct profdata

{

  void *addr;

  off_t size;

  char *hist;

  struct real_gmon_hist_hdr *hist_hdr;

  uint16_t *kcount;

  uint32_t narcs;		/* Number of arcs in toset.  */

  struct here_cg_arc_record *data;

  uint16_t *tos;

  struct here_fromstruct *froms;

};

/* Search tree for symbols.  */

static void *symroot;

static struct known_symbol **sortsym;

static size_t symidx;

static uintmax_t total_ticks;

/* Prototypes for local functions.  */

static struct shobj *load_shobj (const char *name);

static void unload_shobj (struct shobj *shobj);

static struct profdata *load_profdata (const char *name, struct shobj *shobj);

static void unload_profdata (struct profdata *profdata);

static void count_total_ticks (struct shobj *shobj, struct profdata *profdata);

static void count_calls (struct shobj *shobj, struct profdata *profdata);

static void read_symbols (struct shobj *shobj);

static void add_arcs (struct profdata *profdata);

static void generate_flat_profile (struct profdata *profdata);

static void generate_call_graph (struct profdata *profdata);

static void generate_call_pair_list (struct profdata *profdata);

int

main (int argc, char *argv[])

{

  const char *shobj;

  const char *profdata;

  struct shobj *shobj_handle;

  struct profdata *profdata_handle;

  int remaining;

  setlocale (LC_ALL, "");

  /* Initialize the message catalog.  */

  textdomain (_libc_intl_domainname);

  /* Parse and process arguments.  */

  argp_parse (&argp, argc, argv, 0, &remaining, NULL);

  if (argc - remaining == 0 || argc - remaining > 2)

    {

      /* We need exactly two non-option parameter.  */

      argp_help (&argp, stdout, ARGP_HELP_SEE | ARGP_HELP_EXIT_ERR,

		 program_invocation_short_name);

      exit (1);

    }

  /* Get parameters.  */

  shobj = argv[remaining];

  if (argc - remaining == 2)

    profdata = argv[remaining + 1];

  else

    /* No filename for the profiling data given.  We will determine it

       from the soname of the shobj, later.  */

    profdata = NULL;

  /* First see whether we can load the shared object.  */

  shobj_handle = load_shobj (shobj);

  if (shobj_handle == NULL)

    exit (1);

  /* We can now determine the filename for the profiling data, if

     nececessary.  */

  if (profdata == NULL)

    {

      char *newp;

      const char *soname;

      size_t soname_len;

      soname = shobj_handle->soname ?: basename (shobj);

      soname_len = strlen (soname);

      newp = (char *) alloca (soname_len + sizeof ".profile");

      stpcpy (mempcpy (newp, soname, soname_len), ".profile");

      profdata = newp;

    }

  /* Now see whether the profiling data file matches the given object.   */

  profdata_handle = load_profdata (profdata, shobj_handle);

  if (profdata_handle == NULL)

    {

      unload_shobj (shobj_handle);

      exit (1);

    }

  read_symbols (shobj_handle);

  /* Count the ticks.  */

  count_total_ticks (shobj_handle, profdata_handle);

  /* Count the calls.  */

  count_calls (shobj_handle, profdata_handle);

  /* Add the arc information.  */

  add_arcs (profdata_handle);

  /* If no mode is specified fall back to the default mode.  */

  if (mode == NONE)

    mode = DEFAULT_MODE;

  /* Do some work.  */

  if (mode & FLAT_MODE)

    generate_flat_profile (profdata_handle);

  if (mode & CALL_GRAPH_MODE)

    generate_call_graph (profdata_handle);

  if (mode & CALL_PAIRS)

    generate_call_pair_list (profdata_handle);

  /* Free the resources.  */

  unload_shobj (shobj_handle);

  unload_profdata (profdata_handle);

  return 0;

}

/* Handle program arguments.  */

static error_t

parse_opt (int key, char *arg, struct argp_state *state)

{

  switch (key)

    {

    case 'c':

      mode |= CALL_PAIRS;

      break;

    case 'p':

      mode |= FLAT_MODE;

      break;

    case 'q':

      mode |= CALL_GRAPH_MODE;

      break;

    case OPT_TEST:

      do_test = 1;

      break;

    default:

      return ARGP_ERR_UNKNOWN;

    }

  return 0;

}

static char *

more_help (int key, const char *text, void *input)

{

  char *tp = NULL;

  switch (key)

    {

    case ARGP_KEY_HELP_EXTRA:

      /* We print some extra information.  */

      if (asprintf (&tp, gettext ("\

For bug reporting instructions, please see:\n\

%s.\n"), REPORT_BUGS_TO) < 0)

	return NULL;

      return tp;

    default:

      break;

    }

  return (char *) text;

}

/* Print the version information.  */

static void

print_version (FILE *stream, struct argp_state *state)

{

  fprintf (stream, "sprof %s%s\n", PKGVERSION, VERSION);

  fprintf (stream, gettext ("\

Copyright (C) %s Free Software Foundation, Inc.\n\

This is free software; see the source for copying conditions.  There is NO\n\

warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\

"),

	   "2018");

  fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");

}

/* Note that we must not use `dlopen' etc.  The shobj object must not

   be loaded for use.  */

static struct shobj *

load_shobj (const char *name)

{

  struct link_map *map = NULL;

  struct shobj *result;

  ElfW(Addr) mapstart = ~((ElfW(Addr)) 0);

  ElfW(Addr) mapend = 0;

  const ElfW(Phdr) *ph;

  size_t textsize;

  ElfW(Ehdr) *ehdr;

  int fd;

  ElfW(Shdr) *shdr;

  size_t pagesize = getpagesize ();

  /* Since we use dlopen() we must be prepared to work around the sometimes

     strange lookup rules for the shared objects.  If we have a file foo.so

     in the current directory and the user specfies foo.so on the command

     line (without specifying a directory) we should load the file in the

     current directory even if a normal dlopen() call would read the other

     file.  We do this by adding a directory portion to the name.  */

  if (strchr (name, '/') == NULL)

    {

      char *load_name = (char *) alloca (strlen (name) + 3);

      stpcpy (stpcpy (load_name, "./"), name);

      map = (struct link_map *) dlopen (load_name, RTLD_LAZY | __RTLD_SPROF);

    }

  if (map == NULL)

    {

      map = (struct link_map *) dlopen (name, RTLD_LAZY | __RTLD_SPROF);

      if (map == NULL)

	{

	  error (0, errno, _("failed to load shared object `%s'"), name);

	  return NULL;

	}

    }

  /* Prepare the result.  */

  result = (struct shobj *) calloc (1, sizeof (struct shobj));

  if (result == NULL)

    {

      error (0, errno, _("cannot create internal descriptor"));

      dlclose (map);

      return NULL;

    }

  result->name = name;

  result->map = map;

  /* Compute the size of the sections which contain program code.

     This must match the code in dl-profile.c (_dl_start_profile).  */

  for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)

    if (ph->p_type == PT_LOAD && (ph->p_flags & PF_X))

      {

	ElfW(Addr) start = (ph->p_vaddr & ~(pagesize - 1));

	ElfW(Addr) end = ((ph->p_vaddr + ph->p_memsz + pagesize - 1)

			  & ~(pagesize - 1));

	if (start < mapstart)

	  mapstart = start;

	if (end > mapend)

	  mapend = end;

      }

  result->lowpc = ROUNDDOWN ((uintptr_t) (mapstart + map->l_addr),

			     HISTFRACTION * sizeof (HISTCOUNTER));

  result->highpc = ROUNDUP ((uintptr_t) (mapend + map->l_addr),

			    HISTFRACTION * sizeof (HISTCOUNTER));

  if (do_test)

    printf ("load addr: %0#*" PRIxPTR "\n"

	    "lower bound PC: %0#*" PRIxPTR "\n"

	    "upper bound PC: %0#*" PRIxPTR "\n",

	    __ELF_NATIVE_CLASS == 32 ? 10 : 18, map->l_addr,

	    __ELF_NATIVE_CLASS == 32 ? 10 : 18, result->lowpc,

	    __ELF_NATIVE_CLASS == 32 ? 10 : 18, result->highpc);

  textsize = result->highpc - result->lowpc;

  result->kcountsize = textsize / HISTFRACTION;

  result->hashfraction = HASHFRACTION;

  if (do_test)

    printf ("hashfraction = %d\ndivider = %Zu\n",

	    result->hashfraction,

	    result->hashfraction * sizeof (struct here_fromstruct));

  result->tossize = textsize / HASHFRACTION;

  result->fromlimit = textsize * ARCDENSITY / 100;

  if (result->fromlimit < MINARCS)

    result->fromlimit = MINARCS;

  if (result->fromlimit > MAXARCS)

    result->fromlimit = MAXARCS;

  result->fromssize = result->fromlimit * sizeof (struct here_fromstruct);

  result->expected_size = (sizeof (struct gmon_hdr)

			   + 4 + sizeof (struct gmon_hist_hdr)

			   + result->kcountsize

			   + 4 + 4

			   + (result->fromssize

			      * sizeof (struct here_cg_arc_record)));

  if (do_test)

    printf ("expected size: %Zd\n", result->expected_size);

#define SCALE_1_TO_1	0x10000L

  if (result->kcountsize < result->highpc - result->lowpc)

    {

      size_t range = result->highpc - result->lowpc;

      size_t quot = range / result->kcountsize;

      if (quot >= SCALE_1_TO_1)

	result->s_scale = 1;

      else if (quot >= SCALE_1_TO_1 / 256)

	result->s_scale = SCALE_1_TO_1 / quot;

      else if (range > ULONG_MAX / 256)

	result->s_scale = ((SCALE_1_TO_1 * 256)

			   / (range / (result->kcountsize / 256)));

      else

	result->s_scale = ((SCALE_1_TO_1 * 256)

			   / ((range * 256) / result->kcountsize));

    }

  else

    result->s_scale = SCALE_1_TO_1;

  if (do_test)

    printf ("s_scale: %d\n", result->s_scale);

  /* Determine the dynamic string table.  */

  if (map->l_info[DT_STRTAB] == NULL)

    result->dynstrtab = NULL;

  else

    result->dynstrtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);

  if (do_test)

    printf ("string table: %p\n", result->dynstrtab);

  /* Determine the soname.  */

  if (map->l_info[DT_SONAME] == NULL)

    result->soname = NULL;

  else

    result->soname = result->dynstrtab + map->l_info[DT_SONAME]->d_un.d_val;

  if (do_test && result->soname != NULL)

    printf ("soname: %s\n", result->soname);

  /* Now we have to load the symbol table.

     First load the section header table.  */

  ehdr = (ElfW(Ehdr) *) map->l_map_start;

  /* Make sure we are on the right party.  */

  if (ehdr->e_shentsize != sizeof (ElfW(Shdr)))

    abort ();

  /* And we need the shared object file descriptor again.  */

  fd = open (map->l_name, O_RDONLY);

  if (fd == -1)

    /* Dooh, this really shouldn't happen.  We know the file is available.  */

    error (EXIT_FAILURE, errno, _("Reopening shared object `%s' failed"),

	   map->l_name);

  /* Map the section header.  */

  size_t size = ehdr->e_shnum * sizeof (ElfW(Shdr));

  shdr = (ElfW(Shdr) *) alloca (size);

  if (pread (fd, shdr, size, ehdr->e_shoff) != size)

    error (EXIT_FAILURE, errno, _("reading of section headers failed"));

  /* Get the section header string table.  */

  char *shstrtab = (char *) alloca (shdr[ehdr->e_shstrndx].sh_size);

  if (pread (fd, shstrtab, shdr[ehdr->e_shstrndx].sh_size,

	     shdr[ehdr->e_shstrndx].sh_offset)

      != shdr[ehdr->e_shstrndx].sh_size)

    error (EXIT_FAILURE, errno,

	   _("reading of section header string table failed"));

  /* Search for the ".symtab" section.  */

  ElfW(Shdr) *symtab_entry = NULL;

  ElfW(Shdr) *debuglink_entry = NULL;

  for (int idx = 0; idx < ehdr->e_shnum; ++idx)

    if (shdr[idx].sh_type == SHT_SYMTAB

	&& strcmp (shstrtab + shdr[idx].sh_name, ".symtab") == 0)

      {

	symtab_entry = &shdr[idx];

	break;

      }

    else if (shdr[idx].sh_type == SHT_PROGBITS

	     && strcmp (shstrtab + shdr[idx].sh_name, ".gnu_debuglink") == 0)

      debuglink_entry = &shdr[idx];

  /* Get the file name of the debuginfo file if necessary.  */

  int symfd = fd;

  if (symtab_entry == NULL && debuglink_entry != NULL)

    {

      size_t size = debuglink_entry->sh_size;

      char *debuginfo_fname = (char *) alloca (size + 1);

      debuginfo_fname[size] = '\0';

      if (pread (fd, debuginfo_fname, size, debuglink_entry->sh_offset)

	  != size)

	{

	  fprintf (stderr, _("*** Cannot read debuginfo file name: %m\n"));

	  goto no_debuginfo;

	}

      static const char procpath[] = "/proc/self/fd/%d";

      char origprocname[sizeof (procpath) + sizeof (int) * 3];

      snprintf (origprocname, sizeof (origprocname), procpath, fd);

      char *origlink = (char *) alloca (PATH_MAX);

      ssize_t n = readlink (origprocname, origlink, PATH_MAX - 1);

      if (n == -1)

	goto no_debuginfo;

      origlink[n] = '\0';

      /* Try to find the actual file.  There are three places:

	 1. the same directory the DSO is in

	 2. in a subdir named .debug of the directory the DSO is in

	 3. in /usr/lib/debug/PATH-OF-DSO

      */

      char *realname = canonicalize_file_name (origlink);

      char *cp = NULL;

      if (realname == NULL || (cp = strrchr (realname, '/')) == NULL)

	error (EXIT_FAILURE, errno, _("cannot determine file name"));

      /* Leave the last slash in place.  */

      *++cp = '\0';

      /* First add the debuginfo file name only.  */

      static const char usrlibdebug[]= "/usr/lib/debug/";

      char *workbuf = (char *) alloca (sizeof (usrlibdebug)

				       + (cp - realname)

				       + strlen (debuginfo_fname));

      strcpy (stpcpy (workbuf, realname), debuginfo_fname);

      int fd2 = open (workbuf, O_RDONLY);

      if (fd2 == -1)

	{

	  strcpy (stpcpy (stpcpy (workbuf, realname), ".debug/"),

		  debuginfo_fname);

	  fd2 = open (workbuf, O_RDONLY);

	  if (fd2 == -1)

	    {

	      strcpy (stpcpy (stpcpy (workbuf, usrlibdebug), realname),

		      debuginfo_fname);

	      fd2 = open (workbuf, O_RDONLY);

	    }

	}

      if (fd2 != -1)

	{

	  ElfW(Ehdr) ehdr2;

	  /* Read the ELF header.  */

	  if (pread (fd2, &ehdr2, sizeof (ehdr2), 0) != sizeof (ehdr2))

	    error (EXIT_FAILURE, errno,

		   _("reading of ELF header failed"));

	  /* Map the section header.  */

	  size_t size = ehdr2.e_shnum * sizeof (ElfW(Shdr));

	  ElfW(Shdr) *shdr2 = (ElfW(Shdr) *) alloca (size);

	  if (pread (fd2, shdr2, size, ehdr2.e_shoff) != size)

	    error (EXIT_FAILURE, errno,

		   _("reading of section headers failed"));

	  /* Get the section header string table.  */

	  shstrtab = (char *) alloca (shdr2[ehdr2.e_shstrndx].sh_size);

	  if (pread (fd2, shstrtab, shdr2[ehdr2.e_shstrndx].sh_size,

		     shdr2[ehdr2.e_shstrndx].sh_offset)

	      != shdr2[ehdr2.e_shstrndx].sh_size)

	    error (EXIT_FAILURE, errno,

		   _("reading of section header string table failed"));

	  /* Search for the ".symtab" section.  */

	  for (int idx = 0; idx < ehdr2.e_shnum; ++idx)

	    if (shdr2[idx].sh_type == SHT_SYMTAB

		&& strcmp (shstrtab + shdr2[idx].sh_name, ".symtab") == 0)

	      {

		symtab_entry = &shdr2[idx];

		shdr = shdr2;

		symfd = fd2;

		break;

	      }

	  if  (fd2 != symfd)

	    close (fd2);

	}

    }

 no_debuginfo:

  if (symtab_entry == NULL)

    {

      fprintf (stderr, _("\

*** The file `%s' is stripped: no detailed analysis possible\n"),

	      name);

      result->symtab = NULL;

      result->strtab = NULL;

    }

  else

    {

      ElfW(Off) min_offset, max_offset;

      ElfW(Shdr) *strtab_entry;

      strtab_entry = &shdr[symtab_entry->sh_link];

      /* Find the minimum and maximum offsets that include both the symbol

	 table and the string table.  */

      if (symtab_entry->sh_offset < strtab_entry->sh_offset)

	{

	  min_offset = symtab_entry->sh_offset & ~(pagesize - 1);

	  max_offset = strtab_entry->sh_offset + strtab_entry->sh_size;

	}

      else

	{

	  min_offset = strtab_entry->sh_offset & ~(pagesize - 1);

	  max_offset = symtab_entry->sh_offset + symtab_entry->sh_size;

	}

      result->symbol_map = mmap (NULL, max_offset - min_offset,

				 PROT_READ, MAP_SHARED|MAP_FILE, symfd,

				 min_offset);

      if (result->symbol_map == MAP_FAILED)

	error (EXIT_FAILURE, errno, _("failed to load symbol data"));

      result->symtab

	= (const ElfW(Sym) *) ((const char *) result->symbol_map

			       + (symtab_entry->sh_offset - min_offset));

      result->symtab_size = symtab_entry->sh_size;

      result->strtab = ((const char *) result->symbol_map

			+ (strtab_entry->sh_offset - min_offset));

      result->symbol_mapsize = max_offset - min_offset;

    }

  /* Free the descriptor for the shared object.  */

  close (fd);

  if (symfd != fd)

    close (symfd);

  return result;

}

static void

unload_shobj (struct shobj *shobj)

{

  munmap (shobj->symbol_map, shobj->symbol_mapsize);

  dlclose (shobj->map);

}

static struct profdata *

load_profdata (const char *name, struct shobj *shobj)

{

  struct profdata *result;

  int fd;

  struct stat64 st;

  void *addr;

  uint32_t *narcsp;

  size_t fromlimit;

  struct here_cg_arc_record *data;

  struct here_fromstruct *froms;

  uint16_t *tos;

  size_t fromidx;

  size_t idx;

  fd = open (name, O_RDONLY);

  if (fd == -1)

    {

      char *ext_name;

      if (errno != ENOENT || strchr (name, '/') != NULL)

	/* The file exists but we are not allowed to read it or the

	   file does not exist and the name includes a path

	   specification..  */

	return NULL;

      /* A file with the given name does not exist in the current

	 directory, try it in the default location where the profiling

	 files are created.  */

      ext_name = (char *) alloca (strlen (name) + sizeof "/var/tmp/");

      stpcpy (stpcpy (ext_name, "/var/tmp/"), name);

      name = ext_name;

      fd = open (ext_name, O_RDONLY);

      if (fd == -1)

	{

	  /* Even this file does not exist.  */

	  error (0, errno, _("cannot load profiling data"));

	  return NULL;

	}

    }

  /* We have found the file, now make sure it is the right one for the

     data file.  */

  if (fstat64 (fd, &st) < 0)

    {

      error (0, errno, _("while stat'ing profiling data file"));

      close (fd);

      return NULL;

    }

  if ((size_t) st.st_size != shobj->expected_size)

    {

      error (0, 0,

	     _("profiling data file `%s' does not match shared object `%s'"),

	     name, shobj->name);

      close (fd);

      return NULL;

    }

  /* The data file is most probably the right one for our shared

     object.  Map it now.  */

  addr = mmap (NULL, st.st_size, PROT_READ, MAP_SHARED|MAP_FILE, fd, 0);

  if (addr == MAP_FAILED)

    {

      error (0, errno, _("failed to mmap the profiling data file"));

      close (fd);

      return NULL;

    }

  /* We don't need the file desriptor anymore.  */

  if (close (fd) < 0)

    {

      error (0, errno, _("error while closing the profiling data file"));

      munmap (addr, st.st_size);

      return NULL;

    }

  /* Prepare the result.  */

  result = (struct profdata *) calloc (1, sizeof (struct profdata));

  if (result == NULL)

    {

      error (0, errno, _("cannot create internal descriptor"));

      munmap (addr, st.st_size);

      return NULL;

    }

  /* Store the address and size so that we can later free the resources.  */

  result->addr = addr;

  result->size = st.st_size;

  /* Pointer to data after the header.  */

  result->hist = (char *) ((struct gmon_hdr *) addr + 1);

  result->hist_hdr = (struct real_gmon_hist_hdr *) ((char *) result->hist

						    + sizeof (uint32_t));

  result->kcount = (uint16_t *) ((char *) result->hist + sizeof (uint32_t)

				 + sizeof (struct real_gmon_hist_hdr));

  /* Compute pointer to array of the arc information.  */

  narcsp = (uint32_t *) ((char *) result->kcount + shobj->kcountsize

			 + sizeof (uint32_t));

  result->narcs = *narcsp;

  result->data = (struct here_cg_arc_record *) ((char *) narcsp

						+ sizeof (uint32_t));

  /* Create the gmon_hdr we expect or write.  */

  struct real_gmon_hdr

  {

    char cookie[4];

    int32_t version;

    char spare[3 * 4];

  } gmon_hdr;

  if (sizeof (gmon_hdr) != sizeof (struct gmon_hdr)

      || (offsetof (struct real_gmon_hdr, cookie)

	  != offsetof (struct gmon_hdr, cookie))

      || (offsetof (struct real_gmon_hdr, version)

	  != offsetof (struct gmon_hdr, version)))

    abort ();

  memcpy (&gmon_hdr.cookie[0], GMON_MAGIC, sizeof (gmon_hdr.cookie));

  gmon_hdr.version = GMON_SHOBJ_VERSION;

  memset (gmon_hdr.spare, '\0', sizeof (gmon_hdr.spare));

  /* Create the hist_hdr we expect or write.  */

  struct real_gmon_hist_hdr hist_hdr;

  if (sizeof (hist_hdr) != sizeof (struct gmon_hist_hdr)

      || (offsetof (struct real_gmon_hist_hdr, low_pc)

	  != offsetof (struct gmon_hist_hdr, low_pc))

      || (offsetof (struct real_gmon_hist_hdr, high_pc)

	  != offsetof (struct gmon_hist_hdr, high_pc))

      || (offsetof (struct real_gmon_hist_hdr, hist_size)

	  != offsetof (struct gmon_hist_hdr, hist_size))

      || (offsetof (struct real_gmon_hist_hdr, prof_rate)

	  != offsetof (struct gmon_hist_hdr, prof_rate))

      || (offsetof (struct real_gmon_hist_hdr, dimen)

	  != offsetof (struct gmon_hist_hdr, dimen))

      || (offsetof (struct real_gmon_hist_hdr, dimen_abbrev)

	  != offsetof (struct gmon_hist_hdr, dimen_abbrev)))