/* `sln' program to create symbolic links between files.

   Copyright (C) 1998-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   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 <error.h>

#include <errno.h>

#include <libintl.h>

#include <locale.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <errno.h>

#include <ctype.h>

#include <stdio.h>

#include <string.h>

#include <limits.h>

#include "../version.h"

#define PACKAGE _libc_intl_domainname

static int makesymlink (const char *src, const char *dest);

static int makesymlinks (const char *file);

static void usage (void);

int

main (int argc, char **argv)

{

  /* Set locale via LC_ALL.  */

  setlocale (LC_ALL, "");

  /* Set the text message domain.  */

  textdomain (PACKAGE);

  switch (argc)

    {

    case 2:

      if (strcmp (argv[1], "--version") == 0) {

	printf ("sln %s%s\n", PKGVERSION, VERSION);

	return 0;

      } else if (strcmp (argv[1], "--help") == 0) {

	usage ();

	return 0;

      }

      return makesymlinks (argv [1]);

      break;

    case 3:

      return makesymlink (argv [1], argv [2]);

      break;

    default:

      usage ();

      return 1;

      break;

    }

}

static void

usage (void)

{

  printf (_("Usage: sln src dest|file\n\n"));

  printf (_("For bug reporting instructions, please see:\n\

%s.\n"), REPORT_BUGS_TO);

}

static int

makesymlinks (const char *file)

{

  char *buffer = NULL;

  size_t bufferlen = 0;

  int ret;

  int lineno;

  FILE *fp;

  if (strcmp (file, "-") == 0)

    fp = stdin;

  else

    {

      fp = fopen (file, "r");

      if (fp == NULL)

	{

	  fprintf (stderr, _("%s: file open error: %m\n"), file);

	  return 1;

	}

    }

  ret = 0;

  lineno = 0;

  while (!feof_unlocked (fp))

    {

      ssize_t n = getline (&buffer, &bufferlen, fp);

      char *src;

      char *dest;

      char *cp = buffer;

      if (n < 0)

	break;

      if (buffer[n - 1] == '\n')

	buffer[n - 1] = '\0';

      ++lineno;

      while (isspace (*cp))

	++cp;

      if (*cp == '\0')

	/* Ignore empty lines.  */

	continue;

      src = cp;

      do

	++cp;

      while (*cp != '\0' && ! isspace (*cp));

      if (*cp != '\0')

	*cp++ = '\0';

      while (isspace (*cp))

	++cp;

      if (*cp == '\0')

	{

	  fprintf (stderr, _("No target in line %d\n"), lineno);

	  ret = 1;

	  continue;

	}

      dest = cp;

      do

	++cp;

      while (*cp != '\0' && ! isspace (*cp));

      if (*cp != '\0')

	*cp++ = '\0';

      ret |= makesymlink (src, dest);

    }

  fclose (fp);

  return ret;

}

static int

makesymlink (const char *src, const char *dest)

{

  struct stat64 stats;

  const char *error;

  /* Destination must not be a directory. */

  if (lstat64 (dest, &stats) == 0)

    {

      if (S_ISDIR (stats.st_mode))

	{

	  fprintf (stderr, _("%s: destination must not be a directory\n"),

		   dest);

	  return 1;

	}

      else if (unlink (dest) && errno != ENOENT)

	{

	  fprintf (stderr, _("%s: failed to remove the old destination\n"),

		   dest);

	  return 1;

	}

    }

  else if (errno != ENOENT)

    {

      error = strerror (errno);

      fprintf (stderr, _("%s: invalid destination: %s\n"), dest, error);

      return -1;

    }

  if (symlink (src, dest) == 0)

    {

      /* Destination must exist by now. */

      if (access (dest, F_OK))

        {

	  error = strerror (errno);

	  unlink (dest);

	  fprintf (stderr, _("Invalid link from \"%s\" to \"%s\": %s\n"),

		   src, dest, error);

	  return 1;

	}

      return 0;

    }

  else

    {

      error = strerror (errno);

      fprintf (stderr, _("Invalid link from \"%s\" to \"%s\": %s\n"),

	       src, dest, error);

      return 1;

    }

}