find/util.c - master - niceSOFT/findutils

find/util.c
1 156 строк31 KB
James Youngman
find: delete wholly-empty function header comments.
19 июл 2026, 13:20
19 июл 2026, 13:20863ba88
/* util.c -- functions for initializing new tree elements, and other things.
   Copyright (C) 1990-2026 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

/* config.h must always come first. */
#include <config.h>

/* system headers. */
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>
#include <sys/stat.h>           /* for fstatat() */
#include <sys/time.h>
#include <sys/utsname.h>

/* gnulib headers. */
#include "fdleak.h"
#include "progname.h"
#include "quotearg.h"
#include "save-cwd.h"
#include "timespec.h"
#include "xalloc.h"

/* find headers. */
#include "defs.h"
#include "dircallback.h"
#include "bugreports.h"
#include "system.h"


struct debug_option_assoc
{
  const char *name;
  int val;
  const char *docstring;
};
static struct debug_option_assoc debugassoc[] = {
  {"exec", DebugExec,
   "Show diagnostic information relating to -exec, -execdir, -ok and -okdir"},
  {"opt", DebugExpressionTree | DebugTreeOpt,
   "Show diagnostic information relating to optimisation"},
  {"rates", DebugSuccessRates, "Indicate how often each predicate succeeded"},
  {"search", DebugSearch, "Navigate the directory tree verbosely"},
  {"stat", DebugStat, "Trace calls to stat(2) and lstat(2)"},
  {"time", DebugTime,
   "Show diagnostic information relating to time-of-day and timestamp comparisons"},
  {"tree", DebugExpressionTree, "Display the expression tree"},

  {"all", DebugAll, "Set all of the debug flags (but help)"},
  {"help", DebugHelp, "Explain the various -D options"},
};

#define N_DEBUGASSOC (sizeof(debugassoc)/sizeof(debugassoc[0]))




/* Add a primary of predicate type PRED_FUNC (described by ENTRY) to the predicate input list.

   Return a pointer to the predicate node just inserted.

   Fills in the following cells of the new predicate node:

   pred_func        PRED_FUNC
   args(.str)       NULL
   p_type           PRIMARY_TYPE
   p_prec           NO_PREC

   Other cells that need to be filled in are defaulted by
   get_new_pred_chk_op, which is used to ensure that the prior node is
   either not there at all (we are the very first node) or is an
   operator. */
struct predicate *
insert_primary_withpred (const struct parser_table *entry,
                         PRED_FUNC pred_func, const char *arg)
{
  struct predicate *new_pred;

  new_pred = get_new_pred_chk_op (entry, arg);
  new_pred->pred_func = pred_func;
  new_pred->p_name = entry->parser_name;
  new_pred->args.str = NULL;
  new_pred->p_type = PRIMARY_TYPE;
  new_pred->p_prec = NO_PREC;
  return new_pred;
}

/* Add a primary described by ENTRY to the predicate input list.

   Return a pointer to the predicate node just inserted.

   Fills in the following cells of the new predicate node:

   pred_func        PRED_FUNC
   args(.str)       NULL
   p_type           PRIMARY_TYPE
   p_prec           NO_PREC

   Other cells that need to be filled in are defaulted by
   get_new_pred_chk_op, which is used to ensure that the prior node is
   either not there at all (we are the very first node) or is an
   operator. */
struct predicate *
insert_primary (const struct parser_table *entry, const char *arg)
{
  assert (entry->pred_func != NULL);
  return insert_primary_withpred (entry, entry->pred_func, arg);
}

struct predicate *
insert_primary_noarg (const struct parser_table *entry)
{
  return insert_primary (entry, NULL);
}



static void
show_valid_debug_options (int full)
{
  size_t i;
  fputs (_("Valid arguments for -D:\n"), stdout);
  if (full)
    {
      for (i = 0; i < N_DEBUGASSOC; ++i)
        {
          fprintf (stdout, "%-10s %s\n",
                   debugassoc[i].name, debugassoc[i].docstring);
        }
    }
  else
    {
      for (i = 0; i < N_DEBUGASSOC; ++i)
        {
          fprintf (stdout, "%s%s", (i > 0 ? ", " : "      "),
                   debugassoc[i].name);
        }
    }
}

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    {
      fprintf (stderr, _("Try '%s --help' for more information.\n"),
               program_name);
      exit (status);
    }

#define HTL(t) fputs (t, stdout);

  fprintf (stdout, _("\
Usage: %s [-H] [-L] [-P] [-Olevel] [-D debugopts] [path...] [expression]\n"), program_name);

  HTL (_("\n\
Default path is the current directory; default expression is -print.\n\
Expression may consist of: operators, options, tests, and actions.\n"));
  HTL (_("\n\
Operators (decreasing precedence; -and is implicit where no others are given):\n\
      ( EXPR )   ! EXPR   -not EXPR   EXPR1 -a EXPR2   EXPR1 -and EXPR2\n\
      EXPR1 -o EXPR2   EXPR1 -or EXPR2   EXPR1 , EXPR2\n"));
  HTL (_("\n\
Positional options (always true):\n\
      -daystart -follow -nowarn -regextype -warn\n"));
  HTL (_("\n\
Normal options (always true, specified before other expressions):\n\
      -depth -files0-from FILE -maxdepth LEVELS -mindepth LEVELS\n\
      -mount -noleaf -xdev -ignore_readdir_race -noignore_readdir_race\n"));
  HTL (_("\n\
Tests (N can be +N or -N or N):\n\
      -amin N -anewer FILE -atime N -cmin N -cnewer FILE -context CONTEXT\n\
      -ctime N -empty -false -fstype TYPE -gid N -group NAME -ilname PATTERN\n\
      -iname PATTERN -inum N -iwholename PATTERN -iregex PATTERN\n\
      -links N -lname PATTERN -mmin N -mtime N -name PATTERN -newer FILE\n\
      -newerXY REFERENCE -nouser -nogroup -path PATTERN -perm [-/]MODE\n\
      -regex PATTERN -readable -writable -executable\n\
      -wholename PATTERN -size N[bcwkMG] -true -type [bcdpflsD] -uid N\n\
      -used N -user NAME -xtype [bcdpfls]\n"));
  HTL (_("\n\
Actions:\n\
      -delete -print0 -printf FORMAT -fprintf FILE FORMAT -print \n\
      -fprint0 FILE -fprint FILE -ls -fls FILE -prune -quit\n\
      -exec COMMAND ; -exec COMMAND {} + -ok COMMAND ;\n\
      -execdir COMMAND ; -execdir COMMAND {} + -okdir COMMAND ;\n"));

  HTL (_("\n\
Other common options:\n"));
  HTL (_("      --help                   display this help and exit\n"));
  HTL (_
       ("      --version                output version information and exit\n\n"));

  HTL (_("\n\
In -newerXY, XY stands for the combination [aBcm][aBcmt]; see find(1).\n\
\n"));

  show_valid_debug_options (0);
  HTL (_("\n\
Use '-D help' for a description of the options, or see find(1).\n\
\n"));

  explain_how_to_report_bugs (stdout, program_name);
  exit (status);
}

void
set_stat_placeholders (struct stat *p)
{
  (void) p;                     /* silence warning for systems lacking these fields. */
#if HAVE_STRUCT_STAT_ST_BIRTHTIME
  p->st_birthtime = 0;
#endif
#if HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
  p->st_birthtimensec = 0;
#endif
#if HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC
  p->st_birthtimespec.tv_nsec = -1;
#endif
#if HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_SEC
  p->st_birthtimespec.tv_sec = 0;
#else
  /* Avoid pointless compiler warning about unused parameters if none of these
     macros are set to nonzero values. */
  (void) p;
#endif
}


/* Get the stat information for a file, if it is
 * not already known.  Returns 0 on success.
 */
int
get_statinfo (const char *pathname, const char *name, struct stat *p)
{
  /* Set markers in fields so we have a good idea if the implementation
   * didn't bother to set them (e.g., NetBSD st_birthtimespec for MS-DOS
   * files)
   */
  if (!state.have_stat)
    {
      set_stat_placeholders (p);
      if (0 == (*options.xstat) (name, p))
        {
          if (00000 == p->st_mode)
            {
              /* Savannah bug #16378. */
              error (0, 0, _("WARNING: file %s appears to have mode 0000"),
                     quotearg_n_style (0, options.err_quoting_style, name));
              state.exit_status = EXIT_FAILURE;
            }
        }
      else
        {
          if (!options.ignore_readdir_race || (errno != ENOENT))
            {
              nonfatal_target_file_error (errno, pathname);
            }
          return -1;
        }
    }
  state.have_stat = true;
  state.have_type = true;
  state.type = p->st_mode;

  return 0;
}

/* Get the stat/type/inode information for a file, if it is not
 * already known.   Returns 0 on success (or if we did nothing).
 */
static int
get_info (const char *pathname, struct stat *p, struct predicate *pred_ptr)
{
  bool todo = false;

  /* If we need the full stat info, or we need the type info but don't
   * already have it, stat the file now.
   */
  if (pred_ptr->need_stat && !state.have_stat)
    {
      todo = true;              /* need full stat info */
    }
  else if (pred_ptr->need_type && !state.have_type)
    {
      todo = true;              /* need to stat to get the type */
    }
  else if (pred_ptr->need_inum)
    {
      if (!p->st_ino)
        {
          todo = true;          /* need to stat to get the inode number */
        }
      else if ((!state.have_type) || S_ISDIR (p->st_mode))
        {
          /* For now we decide not to trust struct dirent.d_ino for
           * directory entries that are subdirectories, in case this
           * subdirectory is a mount point.  We also need to call a
           * stat function if we don't have st_ino (i.e. it is zero).
           */
          todo = true;
        }
    }
  if (todo)
    {
      if (get_statinfo (pathname, state.rel_pathname, p) != 0)
        return -1;              /* failure. */
    }
  return 0;                     /* success, or nothing to do. */
}

/* Determine if we can use O_NOFOLLOW.
 */
#if defined O_NOFOLLOW
bool
check_nofollow (void)
{
  struct utsname uts;
  float release;

  if (0 == O_NOFOLLOW)
    {
      return false;
    }

  if (0 == uname (&uts))
    {
      /* POSIX requires that atof ignores "unrecognised suffixes"; we specifically
       * want that behaviour. */
      double (*conversion) (const char *) = atof;       /* avoid sc_prohibit_atoi_atof check. */
      release = conversion (uts.release);

      if (0 == strcmp ("Linux", uts.sysname))
        {
          /* Linux kernels 2.1.126 and earlier ignore the O_NOFOLLOW flag. */
          return release >= 2.2f;       /* close enough */
        }
      else if (0 == strcmp ("FreeBSD", uts.sysname))
        {
          /* FreeBSD 3.0-CURRENT and later support it */
          return release >= 3.1f;
        }
    }

  /* Well, O_NOFOLLOW was defined, so we'll try to use it. */
  return true;
}
#endif


static int
exec_cb (void *context)
{
  struct exec_val *execp = context;
  bc_do_exec (&execp->ctl, &execp->state);
  return 0;
}

static void
do_exec (struct exec_val *execp)
{
  run_in_dir (execp->wd_for_exec, exec_cb, execp);
  if (execp->wd_for_exec != initial_wd)
    {
      free_cwd (execp->wd_for_exec);
      free (execp->wd_for_exec);
      execp->wd_for_exec = NULL;
    }
}


/* Examine the predicate list for instances of -execdir or -okdir
 * which have been terminated with '+' (build argument list) rather
 * than ';' (singles only).  If there are any, run them (this will
 * have no effect if there are no arguments waiting).
 */
static void
do_complete_pending_execdirs (struct predicate *p)
{
  if (NULL == p)
    return;

  assert (state.execdirs_outstanding);

  do_complete_pending_execdirs (p->pred_left);

  /* We only want to do work here if there is a dir-local pending
   * exec.  This is because the completion of work for -exec ... {} +
   * happens when the program exits, not when we leave a directory.
   */
  if (pred_is (p, pred_okdir) || pred_is (p, pred_execdir))
    {
      /* It's an exec-family predicate.  p->args.exec_val is valid. */
      assert (predicate_uses_exec (p));
      if (p->args.exec_vec.multiple)
        {
          struct exec_val *execp = &p->args.exec_vec;

          /* This one was terminated by '+' and so might have some
           * left... Run it if necessary.
           */
          if (execp->state.todo)
            {
              /* There are not-yet-executed arguments. */
              do_exec (execp);
            }
        }
    }

  do_complete_pending_execdirs (p->pred_right);
}

void
complete_pending_execdirs (void)
{
  if (state.execdirs_outstanding)
    {
      do_complete_pending_execdirs (get_eval_tree ());
      state.execdirs_outstanding = false;
    }
}

/* Examine the predicate list for instances of -exec which have been
 * terminated with '+' (build argument list) rather than ';' (singles
 * only).  If there are any, run them (this will have no effect if
 * there are no arguments waiting).
 */
void
complete_pending_execs (struct predicate *p)
{
  if (NULL == p)
    return;
  complete_pending_execs (p->pred_left);

  /* It's an exec-family predicate then p->args.exec_val is valid
   * and we can check it.
   */
  if (predicate_uses_exec (p) && p->args.exec_vec.multiple)
    {
      struct exec_val *execp = &p->args.exec_vec;

      /* This one was terminated by '+' and so might have some
       * left... Run it if necessary.  Set state.exit_status if
       * there are any problems.
       */
      if (execp->state.todo)
        {
          /* There are not-yet-executed arguments. */
          bc_do_exec (&execp->ctl, &execp->state);
        }
    }

  complete_pending_execs (p->pred_right);
}

void
record_initial_cwd (void)
{
  initial_wd = xmalloc (sizeof (*initial_wd));
  if (0 != save_cwd (initial_wd))
    {
      const char *wd_name = (initial_wd->desc < 0
                             && initial_wd->name) ? initial_wd->name : NULL;
      if (wd_name)
        {
          error (EXIT_FAILURE, errno,
                 _("Failed to save initial working directory %s"), wd_name);
        }
      else
        {
          error (EXIT_FAILURE, errno,
                 _("Failed to save initial working directory"));
        }
    }
}

static void
cleanup_initial_cwd (void)
{
  if (0 == restore_cwd (initial_wd))
    {
      free_cwd (initial_wd);
      free (initial_wd);
      initial_wd = NULL;
    }
  else
    {
      const char *wd_name = (initial_wd->desc < 0
                             && initial_wd->name) ? initial_wd->name : NULL;
      if (wd_name)
        {
          error (0, errno,
                 _("Failed to restore initial working directory %s"),
                 wd_name);
        }
      else
        {
          error (0, errno, _("Failed to restore initial working directory"));
        }
      /* since we may already be in atexit, die with _exit(). */
      _exit (EXIT_FAILURE);
    }
}


static void
traverse_tree (struct predicate *tree, void (*callback) (struct predicate *))
{
  if (tree->pred_left)
    traverse_tree (tree->pred_left, callback);

  callback (tree);

  if (tree->pred_right)
    traverse_tree (tree->pred_right, callback);
}

/* After sharefile_destroy is called, our output file
 * pointers will be dangling (fclose will already have
 * been called on them).  NULL these out.
 */
static void
undangle_file_pointers (struct predicate *p)
{
  if (pred_is (p, pred_fprint)
      || pred_is (p, pred_fprintf)
      || pred_is (p, pred_fls) || pred_is (p, pred_fprint0))
    {
      /* The file was already fclose()d by sharefile_destroy. */
      p->args.printf_vec.stream = NULL;
    }
}

/* Complete any outstanding commands.
 * Flush and close any open files.
 */
void
cleanup (void)
{
  struct predicate *eval_tree = get_eval_tree ();
  if (eval_tree)
    {
      traverse_tree (eval_tree, complete_pending_execs);
      complete_pending_execdirs ();
    }

  /* Close output files and NULL out references to them. */
  sharefile_destroy (state.shared_files);
  if (eval_tree)
    traverse_tree (eval_tree, undangle_file_pointers);

  cleanup_initial_cwd ();

  if (fd_leak_check_is_enabled ())
    {
      complain_about_leaky_fds ();
      forget_non_cloexec_fds ();
    }

  if (fflush (stdout) == EOF)
    nonfatal_nontarget_file_error (errno, "standard output");
}


static int
fallback_stat (const char *name, struct stat *p, int prev_rv)
{
  /* Our original stat() call failed.  Perhaps we can't follow a
   * symbolic link.  If that might be the problem, lstat() the link.
   * Otherwise, admit defeat.
   */
  switch (errno)
    {
    case ENOENT:
    case ENOTDIR:
      if (options.debug_options & DebugStat)
        fprintf (stderr,
                 "fallback_stat(): stat(%s) failed; falling back on lstat()\n",
                 name);
      return fstatat (state.cwd_dir_fd, name, p, AT_SYMLINK_NOFOLLOW);

    case EACCES:
    case EIO:
    case ELOOP:
    case ENAMETOOLONG:
#ifdef EOVERFLOW
    case EOVERFLOW:            /* EOVERFLOW is not #defined on UNICOS. */
#endif
    default:
      return prev_rv;
    }
}


/* optionh_stat() implements the stat operation when the -H option is
 * in effect.
 *
 * If the item to be examined is a command-line argument, we follow
 * symbolic links.  If the stat() call fails on the command-line item,
 * we fall back on the properties of the symbolic link.
 *
 * If the item to be examined is not a command-line argument, we
 * examine the link itself.
 */
int
optionh_stat (const char *name, struct stat *p)
{
  if (AT_FDCWD != state.cwd_dir_fd)
    assert (state.cwd_dir_fd >= 0);
  set_stat_placeholders (p);
  if (0 == state.curdepth)
    {
      /* This file is from the command line; deference the link (if it
       * is a link).
       */
      int rv;
      rv = fstatat (state.cwd_dir_fd, name, p, 0);
      if (0 == rv)
        return 0;               /* success */
      else
        return fallback_stat (name, p, rv);
    }
  else
    {
      /* Not a file on the command line; do not dereference the link.
       */
      return fstatat (state.cwd_dir_fd, name, p, AT_SYMLINK_NOFOLLOW);
    }
}

/* optionl_stat() implements the stat operation when the -L option is
 * in effect.  That option makes us examine the thing the symbolic
 * link points to, not the symbolic link itself.
 */
int
optionl_stat (const char *name, struct stat *p)
{
  int rv;
  if (AT_FDCWD != state.cwd_dir_fd)
    assert (state.cwd_dir_fd >= 0);

  set_stat_placeholders (p);
  rv = fstatat (state.cwd_dir_fd, name, p, 0);
  if (0 == rv)
    return 0;                   /* normal case. */
  else
    return fallback_stat (name, p, rv);
}

/* optionp_stat() implements the stat operation when the -P option is
 * in effect (this is also the default).  That option makes us examine
 * the symbolic link itself, not the thing it points to.
 */
int
optionp_stat (const char *name, struct stat *p)
{
  assert ((state.cwd_dir_fd >= 0) || (state.cwd_dir_fd == AT_FDCWD));
  set_stat_placeholders (p);
  return fstatat (state.cwd_dir_fd, name, p, AT_SYMLINK_NOFOLLOW);
}


static uintmax_t stat_count = 0u;

int
debug_stat (const char *file, struct stat *bufp)
{
  ++stat_count;
  fprintf (stderr, "debug_stat (%s)\n", file);

  switch (options.symlink_handling)
    {
    case SYMLINK_ALWAYS_DEREF:
      return optionl_stat (file, bufp);
    case SYMLINK_DEREF_ARGSONLY:
      return optionh_stat (file, bufp);
    case SYMLINK_NEVER_DEREF:
      return optionp_stat (file, bufp);
    }
   /*NOTREACHED*/ assert (0);
  return -1;
}


bool
following_links (void)
{
  switch (options.symlink_handling)
    {
    case SYMLINK_ALWAYS_DEREF:
      return true;
    case SYMLINK_DEREF_ARGSONLY:
      return (state.curdepth == 0);
    case SYMLINK_NEVER_DEREF:
    default:
      return false;
    }
}


/* Take a "mode" indicator and fill in the files of 'state'.
 */
bool
digest_mode (mode_t *mode,
             const char *pathname,
             const char *name, struct stat *pstat, bool leaf)
{
  /* If we know the type of the directory entry, and it is not a
   * symbolic link, we may be able to avoid a stat() or lstat() call.
   */
  if (*mode)
    {
      if (S_ISLNK (*mode) && following_links ())
        {
          /* mode is wrong because we should have followed the symlink. */
          if (get_statinfo (pathname, name, pstat) != 0)
            return false;
          *mode = state.type = pstat->st_mode;
          state.have_type = true;
        }
      else
        {
          state.have_type = true;
          pstat->st_mode = state.type = *mode;
        }
    }
  else
    {
      /* Mode is not yet known; may have to stat the file unless we
       * can deduce that it is not a directory (which is all we need to
       * know at this stage)
       */
      if (leaf)
        {
          state.have_stat = false;
          state.have_type = false;
          state.type = 0;
        }
      else
        {
          if (get_statinfo (pathname, name, pstat) != 0)
            return false;

          /* If -L is in effect and we are dealing with a symlink,
           * st_mode is the mode of the pointed-to file, while mode is
           * the mode of the directory entry (S_IFLNK).  Hence now
           * that we have the stat information, override "mode".
           */
          state.type = *mode = pstat->st_mode;
          state.have_type = true;
        }
    }

  /* success. */
  return true;
}


/* Return true if there are no predicates with no_default_print in
   predicate list PRED, false if there are any.
   Returns true if default print should be performed */

bool
default_prints (struct predicate *pred)
{
  while (pred != NULL)
    {
      if (pred->no_default_print)
        return (false);
      pred = pred->pred_next;
    }
  return (true);
}

bool
looks_like_expression (const char *arg, bool leading)
{
  switch (arg[0])
    {
    case '-':
      if (arg[1])               /* "-foo" is an expression.  */
        return true;
      else
        return false;           /* Just "-" is a filename. */
      break;

    case ')':
    case ',':
      if (arg[1])
        return false;           /* )x and ,z are not expressions */
      else
        return !leading;        /* A leading ) or , is not either */

      /* ( and ! are part of an expression, but (2 and !foo are
       * filenames.
       */
    case '!':
    case '(':
      if (arg[1])
        return false;
      else
        return true;

    default:
      return false;
    }
}

static void
process_debug_options (char *arg)
{
  const char *p;
  char *token_context = NULL;
  const char delimiters[] = ",";
  bool empty = true;
  size_t i;

  p = strtok_r (arg, delimiters, &token_context);
  while (p)
    {
      empty = false;

      for (i = 0; i < N_DEBUGASSOC; ++i)
        {
          if (0 == strcmp (debugassoc[i].name, p))
            {
              options.debug_options |= debugassoc[i].val;
              break;
            }
        }
      if (i >= N_DEBUGASSOC)
        {
          error (0, 0, _("Ignoring unrecognised debug flag %s"),
                 quotearg_n_style (0, options.err_quoting_style, arg));
        }
      p = strtok_r (NULL, delimiters, &token_context);
    }
  if (empty)
    {
      error (0, 0, _("Empty argument to the -D option."));
      usage (EXIT_FAILURE);
    }
  else if (options.debug_options & DebugHelp)
    {
      show_valid_debug_options (1);
      exit (EXIT_SUCCESS);
    }
}


static void
process_optimisation_option (const char *arg)
{
  if (0 == arg[0])
    {
      error (EXIT_FAILURE, 0,
             _
             ("The -O option must be immediately followed by a decimal integer"));
    }
  else
    {
      unsigned long opt_level;
      char *end;

      if (!isdigit ((unsigned char) arg[0]))
        {
          error (EXIT_FAILURE, 0,
                 _("Please specify a decimal number immediately after -O"));
        }
      else
        {
          int prev_errno = errno;
          errno = 0;

          opt_level = strtoul (arg, &end, 10);
          if ((0 == opt_level) && (end == arg))
            {
              error (EXIT_FAILURE, 0,
                     _
                     ("Please specify a decimal number immediately after -O"));
            }
          else if (*end)
            {
              /* unwanted trailing characters. */
              error (EXIT_FAILURE, 0, _("Invalid optimisation level %s"),
                     arg);
            }
          else if ((ULONG_MAX == opt_level) && errno)
            {
              error (EXIT_FAILURE, errno,
                     _("Invalid optimisation level %s"), arg);
            }
          else if (opt_level > USHRT_MAX)
            {
              /* tricky to test, as on some platforms USHORT_MAX and ULONG_MAX
               * can have the same value, though this is unusual.
               */
              error (EXIT_FAILURE, 0,
                     _("Optimisation level %lu is too high.  "
                       "If you want to find files very quickly, "
                       "consider using GNU locate."), opt_level);
            }
          else
            {
              options.optimisation_level = opt_level;
              errno = prev_errno;
            }
        }
    }
}

int
process_leading_options (int argc, char *argv[])
{
  int i, end_of_leading_options;

  for (i = 1; (end_of_leading_options = i) < argc; ++i)
    {
      if (0 == strcmp ("-H", argv[i]))
        {
          /* Meaning: dereference symbolic links on command line, but nowhere else. */
          set_follow_state (SYMLINK_DEREF_ARGSONLY);
        }
      else if (0 == strcmp ("-L", argv[i]))
        {
          /* Meaning: dereference all symbolic links. */
          set_follow_state (SYMLINK_ALWAYS_DEREF);
        }
      else if (0 == strcmp ("-P", argv[i]))
        {
          /* Meaning: never dereference symbolic links (default). */
          set_follow_state (SYMLINK_NEVER_DEREF);
        }
      else if (0 == strcmp ("--", argv[i]))
        {
          /* -- signifies the end of options. */
          end_of_leading_options = i + 1;       /* Next time start with the next option */
          break;
        }
      else if (0 == strcmp ("-D", argv[i]))
        {
          if (argc <= i + 1)
            {
              error (0, 0, _("Missing argument after the -D option."));
              usage (EXIT_FAILURE);
            }
          process_debug_options (argv[i + 1]);
          ++i;                  /* skip the argument too. */
        }
      else if (0 == strncmp ("-O", argv[i], 2))
        {
          process_optimisation_option (argv[i] + 2);
        }
      else
        {
          /* Hmm, must be one of
           * (a) A path name
           * (b) A predicate
           */
          end_of_leading_options = i;   /* Next time start with this option */
          break;
        }
    }
  return end_of_leading_options;
}

void
set_option_defaults (struct options *p)
{
  if (getenv ("POSIXLY_CORRECT"))
    p->posixly_correct = true;
  else
    p->posixly_correct = false;

  /* We call check_nofollow() before setlocale() because the numbers
   * for which we check (in the results of uname) definitely have "."
   * as the decimal point indicator even under locales for which that
   * is not normally true.   Hence atof would do the wrong thing
   * if we call it after setlocale().
   */
#ifdef O_NOFOLLOW
  p->open_nofollow_available = check_nofollow ();
#else
  p->open_nofollow_available = false;
#endif

  p->regex_options = RE_SYNTAX_EMACS;

  if (isatty (0))
    {
      p->warnings = true;
      p->literal_control_chars = false;
    }
  else
    {
      p->warnings = false;
      p->literal_control_chars = false; /* may change */
    }
  if (p->posixly_correct)
    {
      p->warnings = false;
    }

  p->do_dir_first = true;
  p->explicit_depth = false;
  p->maxdepth = p->mindepth = -1;

  p->start_time = current_timespec ();
  p->cur_day_start.tv_sec = p->start_time.tv_sec - DAYSECS;
  p->cur_day_start.tv_nsec = p->start_time.tv_nsec;

  p->full_days = false;
  p->mount = p->xdev = false;
  p->ignore_readdir_race = false;

  if (p->posixly_correct)
    p->output_block_size = 512;
  else
    p->output_block_size = 1024;

  p->debug_options = 0uL;
  p->optimisation_level = 1;

  if (getenv ("FIND_BLOCK_SIZE"))
    {
      /* Support for FIND_BLOCK_SIZE was removed in 2003
       * (7da8b17cf1b690c8ef016eca2ae50c21e5a9d911).
       */
      error (EXIT_FAILURE, 0,
             _("The environment variable FIND_BLOCK_SIZE is not supported, "
               "the only thing that affects the block size is the "
               "POSIXLY_CORRECT environment variable"));
    }

#if LEAF_OPTIMISATION
  /* The leaf optimisation is enabled. */
  p->no_leaf_check = false;
#else
  /* The leaf optimisation is disabled. */
  p->no_leaf_check = true;
#endif

  set_follow_state (SYMLINK_NEVER_DEREF);       /* The default is equivalent to -P. */

  p->err_quoting_style = locale_quoting_style;

  p->files0_from = NULL;
  p->ok_prompt_stdin = false;
}


bool
apply_predicate (const char *pathname, struct stat *stat_buf,
                 struct predicate *p)
{
  ++p->perf.visits;

  if (p->need_stat || p->need_type || p->need_inum)
    {
      /* We may need a stat here. */
      if (get_info (pathname, stat_buf, p) != 0)
        return false;
    }
  if ((p->pred_func) (pathname, stat_buf, p))
    {
      ++(p->perf.successes);
      return true;
    }
  else
    {
      return false;
    }
}


bool
is_exec_in_local_dir (const PRED_FUNC pred_func)
{
  return pred_execdir == pred_func || pred_okdir == pred_func;
}

const char *
safely_quote_err_filename (int n, char const *arg)
{
  return quotearg_n_style (n, options.err_quoting_style, arg);
}

static void
report_file_err (int exitval, int errno_value,
                 bool is_target_file, const char *name)
{
  /* It is important that the errno value is passed in as a function
   * argument before we call safely_quote_err_filename(), because otherwise
   * we might find that safely_quote_err_filename() changes errno.
   */
  if (!is_target_file || !state.already_issued_stat_error_msg)
    {
      error (exitval, errno_value, "%s", safely_quote_err_filename (0, name));
      state.exit_status = EXIT_FAILURE;
    }
  if (is_target_file)
    {
      state.already_issued_stat_error_msg = true;
    }
}

void
nonfatal_target_file_error (int errno_value, const char *name)
{
  report_file_err (0, errno_value, true, name);
}

/* fatal_target_file_error
 *
 * Report an error on a target file (i.e. a file we are searching).
 * Such errors are only reported once per searched file.
 */
void
fatal_target_file_error (int errno_value, const char *name)
{
  report_file_err (1, errno_value, true, name);
   /*NOTREACHED*/ abort ();
}

void
nonfatal_nontarget_file_error (int errno_value, const char *name)
{
  report_file_err (0, errno_value, false, name);
}

void
fatal_nontarget_file_error (int errno_value, const char *name)
{
  /* We're going to exit fatally, so make sure we always issue the error
   * message, even if it will be duplicate.   Motivation: otherwise it may
   * not be clear what went wrong.
   */
  state.already_issued_stat_error_msg = false;
  report_file_err (1, errno_value, false, name);
   /*NOTREACHED*/ abort ();
}