Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-01/ohlutil.zip/MKFIFO.C

C/C++ Source or Header | 1990-06-22 | 5.0 KB | 214 lines

/* mkfifo -- make fifo's (named pipes)
   Copyright (C) 1990 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 1, 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* Usage: mkfifo [-p] [-m mode] [+path] [+mode mode] path...

   Options:
   -p, +path        Ensure that the given path(s) exist:
            Make any missing parent directories for each argument.
            Parent dirs default to umask modified by `u+wx'.
            Do not consider an argument fifo that already
            exists to be an error.
   -m, +mode mode    Set the mode of created fifo's to `mode', which is
            symbolic as in chmod and uses the umask as a point of
            departure.

   David MacKenzie <[e-mail]>  */

#include <stdio.h>
#include <sys/types.h>
#include "system.h"
#include "getopt.h"
#include "modechange.h"

#ifdef STDC_HEADERS
#include <errno.h>
#include <stdlib.h>
#else
extern int errno;
#endif

#ifndef _POSIX_SOURCE
#define mkfifo(path, mode) (mknod ((path), (mode) | S_IFIFO, 0))
#endif

int make_path ();
void error ();
void strip_trailing_slashes ();
void usage ();

/* If nonzero, ensure that a path exists.  */
int path_mode;

/* The name this program was run with. */
char *program_name;

struct option longopts[] =
{
  {"mode", 1, NULL, 'm'},
  {"path", 0, &path_mode, 1},
  {NULL, 0, NULL, 0}
};

void
main (argc, argv)
     int argc;
     char **argv;
{
  unsigned short newmode;
  unsigned short parent_mode;
  struct mode_change *change;
  char *symbolic_mode;
  int errors = 0;
  int optc;
  int ind;

  program_name = argv[0];
  path_mode = 0;
  symbolic_mode = NULL;

  while ((optc = getopt_long (argc, argv, "pm:", longopts, &ind)) != EOF)
    {
      if (optc == 0 && longopts[ind].flag == 0)
    optc = longopts[ind].val;
      switch (optc)
    {
    case 0:            /* Long option. */
      break;
    case 'p':
      path_mode = 1;
      break;
    case 'm':
      symbolic_mode = optarg;
      break;
    default:
      usage ();
    }
    }

  if (optind == argc)
    usage ();

  newmode = 0777 & ~umask (0);
  parent_mode = newmode | 0300;    /* u+wx */
  newmode &= ~0111;        /* Remove execute permission. */
  if (symbolic_mode)
    {
      change = mode_compile (symbolic_mode, MODE_MASK_EQUALS | MODE_MASK_PLUS);
      if (change == MODE_INVALID)
    error (1, 0, "invalid mode");
      else if (change == MODE_MEMORY_EXHAUSTED)
    error (1, 0, "virtual memory exhausted");
      newmode = mode_adjust (newmode, change);
    }

  for (; optind < argc; ++optind)
    {
      strip_trailing_slashes (argv[optind]);
      if (path_mode)
    errors |= make_path (argv[optind], newmode, parent_mode);
      else if (mkfifo (argv[optind], newmode))
    {
      error (0, errno, "cannot make fifo `%s'", argv[optind]);
      errors = 1;
    }
    }

  exit (errors);
}

/* Make sure fifo `path' and all leading directories exist,
   and give it permission mode `mode'.
   If any leading directories are created, give them permission
   mode `parent_mode'.
   Return 0 if successful, 1 if errors occur. */

int
make_path (path, mode, parent_mode)
     char *path;
     unsigned short mode;
     unsigned short parent_mode;
{
  char *slash;
  struct stat stats;

  if (stat (path, &stats))
    {
      slash = path;
      while (*slash == '/')
    slash++;
      while (slash = index (slash, '/'))
    {
      *slash = 0;
      if (stat (path, &stats))
        {
          if (mkdir (path, parent_mode))
        {
          error (0, errno, "cannot make directory `%s'", path);
          return 1;
        }
        }
      else if ((stats.st_mode & S_IFMT) != S_IFDIR)
        {
          error (0, 0, "`%s' is not a directory", path);
          return 1;
        }
      *slash++ = '/';
    }

      if (mkfifo (path, mode))
    {
      error (0, errno, "cannot make fifo `%s'", path);
      return 1;
    }
    }
  else if ((stats.st_mode & S_IFMT) != S_IFIFO)
    {
      error (0, 0, "`%s' is not a fifo", path);
      return 1;
    }
  else if (chmod (path, mode))
    {
      error (0, errno, "cannot change mode of `%s'", path);
      return 1;
    }
  return 0;
}

/* Remove trailing slashes from PATH; they cause some system calls to fail. */

void
strip_trailing_slashes (path)
     char *path;
{
  int last;

  last = strlen (path) - 1;
  while (last > 0 && path[last] == '/')
    path[last--] = '\0';
}

void
usage ()
{
  fprintf (stderr, "\
Usage: %s [-p] [-m mode] [+path] [+mode mode] path...\n",
       program_name);
  exit (1);
}