Serving the Web/ServingTheWeb1995.disc1of1.iso/linux/slacksrce/d/libc/libc-4.6/libc-4/libc-linux/io/ftw.c

C/C++ Source or Header | 1994-12-08 | 5.0 KB | 237 lines

/* Copyright (C) 1992, 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ian Lance Taylor ([e-mail]).

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <ftw.h>

#ifdef linux
#define d_namlen    d_reclen
#endif

/* Traverse one level of a directory tree.  */

static int
#ifdef linux
DEFUN (ftw_dir, (dirs, level, descriptors, dir, len, func),
       DIR **dirs AND int level AND int descriptors AND
       char *dir AND size_t len AND
       __ftw_func_t func)
#else
DEFUN (ftw_dir, (dirs, level, descriptors, dir, len, func),
       DIR **dirs AND int level AND int descriptors AND
       char *dir AND size_t len AND
       int EXFUN((*func), (CONST char *file, struct stat *status,
               int flag)))
#endif
{
  int got;
  struct dirent *entry;

  got = 0;

  errno = 0;

  while ((entry = readdir (dirs[level])) != NULL)
    {
      struct stat s;
      int flag, ret, newlev;

      ++got;

      if (entry->d_name[0] == '.'
      && (entry->d_namlen == 1 ||
          (entry->d_namlen == 2 && entry->d_name[1] == '.')))
    {
      errno = 0;
      continue;
    }

      if (entry->d_namlen + len + 1 > PATH_MAX)
    {
#ifdef ENAMETOOLONG
      errno = ENAMETOOLONG;
#else
      errno = ENOMEM;
#endif
      return -1;
    }

      dir[len] = '/';
      memcpy ((PTR) (dir + len + 1), (PTR) entry->d_name,
          entry->d_namlen + 1);

      if (stat (dir, &s) < 0)
    {
      /* Following POSIX.1 2.4 ENOENT is returned if the file cannot
       * be stat'ed.  This can happen for a file returned by readdir
       * if it's an unresolved symbolic link.  This should be regarded
       * as an forgivable error.  -- Uli.  */
      if (errno != EACCES && errno != ENOENT)
        return -1;
      flag = FTW_NS;
    }
      else if (S_ISDIR (s.st_mode))
    {
      newlev = (level + 1) % descriptors;

      if (dirs[newlev] != NULL)
        closedir (dirs[newlev]);

      dirs[newlev] = opendir (dir);
      if (dirs[newlev] != NULL)
        flag = FTW_D;
      else
        {
          if (errno != EACCES)
        return -1;
          flag = FTW_DNR;
        }
    }
      else
    flag = FTW_F;

      ret = (*func) (dir, &s, flag);

      if (flag == FTW_D)
    {
      if (ret == 0)
        ret = ftw_dir (dirs, newlev, descriptors, dir,
               entry->d_namlen + len + 1, func);
      if (dirs[newlev] != NULL)
        {
          int save;

          save = errno;
          closedir (dirs[newlev]);
          errno = save;
          dirs[newlev] = NULL;
        }
    }

      if (ret != 0)
    return ret;

      if (dirs[level] == NULL)
    {
      int skip;

      dir[len] = '\0';
      dirs[level] = opendir (dir);
      if (dirs[level] == NULL)
        return -1;
      skip = got;
      while (skip-- != 0)
        {
          errno = 0;
          if (readdir (dirs[level]) == NULL)
        return errno == 0 ? 0 : -1;
        }
    }

      errno = 0;
    }

  return errno == 0 ? 0 : -1;
}

/* Call a function on every element in a directory tree.  */


int
#ifdef linux
DEFUN(ftw, (dir, func, descriptors),
      CONST char *dir AND
      __ftw_func_t func AND int descriptors)
#else
DEFUN(ftw, (dir, func, descriptors),
      CONST char *dir AND
      *func), (CONST char *file, struct stat *status,
              int flag)) AND
      int descriptors)
#endif
{
  DIR **dirs;
  size_t len;
  char buf[PATH_MAX + 1];
  struct stat s;
  int flag, ret;
  int i;

  if (descriptors <= 0)
    descriptors = 1;

  dirs = (DIR **) __alloca (descriptors * sizeof (DIR *));
  i = descriptors;
  while (i-- > 0)
    dirs[i] = NULL;

  if (stat (dir, &s) < 0)
    {
      /* Following POSIX.1 2.4 ENOENT is returned if the file cannot
       * be stat'ed.  This can happen for a file returned by readdir
       * if it's an unresolved symbolic link.  This should be regarded
       * as an forgivable error.  -- Uli.  */
      if (errno != EACCES && errno != ENOENT)
    return -1;
      flag = FTW_NS;
    }
  else if (S_ISDIR (s.st_mode))
    {
      dirs[0] = opendir (dir);
      if (dirs[0] != NULL)
    flag = FTW_D;
      else
    {
      if (errno != EACCES)
        return -1;
      flag = FTW_DNR;
    }
    }
  else
    flag = FTW_F;

  len = strlen (dir);
  memcpy ((PTR) buf, (PTR) dir, len + 1);

  ret = (*func) (buf, &s, flag);

  if (flag == FTW_D)
    {
      if (ret == 0)
    ret = ftw_dir (dirs, 0, descriptors, buf, len, func);
      if (dirs[0] != NULL)
    {
      int save;

      save = errno;
      closedir (dirs[0]);
      errno = save;
    }
    }

  return ret;
}