genfile.c

gnu tar 源码包。 tar 软件是 Unix 系统下的一个打包软件

	error (EXIT_FAILURE, 0, _("file name contains null character"));
      obstack_1grow (stk, c);
      counter++;
    }

  obstack_1grow (stk, 0);

  return (counter == 0 && c == EOF);
}

void
generate_files_from_list ()
{
  FILE *fp = strcmp (files_from, "-") ? fopen (files_from, "rb") : stdin;
  struct obstack stk;

  if (!fp)
    error (EXIT_FAILURE, errno, _("cannot open `%s'"), files_from);

  obstack_init (&stk);
  while (!read_name_from_file (fp, &stk))
    {
      char *name = obstack_finish (&stk);
      generate_simple_file (name);
      verify_file (name);
      obstack_free (&stk, name);
    }
  fclose (fp);
  obstack_free (&stk, NULL);
}


/* Generate Mode: sparse files */

static void
mkhole (int fd, off_t displ)
{
  if (lseek (fd, displ, SEEK_CUR) == -1)
    error (EXIT_FAILURE, errno, "lseek");
  ftruncate (fd, lseek (fd, 0, SEEK_CUR));
}

static void
mksparse (int fd, off_t displ, char *marks)
{
  if (lseek (fd, displ, SEEK_CUR) == -1)
    error (EXIT_FAILURE, errno, "lseek");

  for (; *marks; marks++)
    {
      memset (buffer, *marks, block_size);
      if (write (fd, buffer, block_size) != block_size)
	error (EXIT_FAILURE, errno, "write");
    }
}

static void
generate_sparse_file (int argc, char **argv)
{
  int i;
  int fd;
  int flags = O_CREAT | O_RDWR | O_BINARY;

  if (!file_name)
    error (EXIT_FAILURE, 0,
	   _("cannot generate sparse files on standard output, use --file option"));
  if (!seek_offset)
    flags |= O_TRUNC;
  fd = open (file_name, flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
  if (fd < 0)
    error (EXIT_FAILURE, errno, _("cannot open `%s'"), file_name);

  buffer = xmalloc (block_size);

  file_length = 0;

  for (i = 0; i < argc; i += 2)
    {
      off_t displ = get_size (argv[i], 1);
      file_length += displ;

      if (i == argc-1)
	{
	  mkhole (fd, displ);
	  break;
	}
      else
	{
	  file_length += block_size * strlen (argv[i+1]);
	  mksparse (fd, displ, argv[i+1]);
	}
    }

  close (fd);
}


/* Status Mode */

void
print_time (time_t t)
{
  char buf[20]; /* ccyy-mm-dd HH:MM:SS\0 */
  strftime (buf, sizeof buf, "%Y-%m-%d %H:%M:%S", gmtime (&t));
  printf ("%s ", buf);
}

void
print_stat (const char *name)
{
  char *fmt, *p;
  struct stat st;
  char buf[UINTMAX_STRSIZE_BOUND];

  if (stat (name, &st))
    {
      error (0, errno, _("stat(%s) failed"), name);
      return;
    }

  fmt = strdup (stat_format);
  for (p = strtok (fmt, ","); p; )
    {
      if (memcmp (p, "st_", 3) == 0)
	p += 3;
      if (strcmp (p, "name") == 0)
	printf ("%s", name);
      else if (strcmp (p, "dev") == 0)
	printf ("%lu", (unsigned long) st.st_dev);
      else if (strcmp (p, "ino") == 0)
	printf ("%lu", (unsigned long) st.st_ino);
      else if (strncmp (p, "mode", 4) == 0)
	{
	  mode_t mask = ~0;

	  if (ispunct (p[4]))
	    {
	      char *q;

	      mask = strtoul (p + 5, &q, 8);
	      if (*q)
		{
		  printf ("\n");
		  error (EXIT_FAILURE, 0, _("incorrect mask (near `%s')"), q);
		}
	    }
	  else if (p[4])
	    {
	      printf ("\n");
	      error (EXIT_FAILURE, 0, _("Unknown field `%s'"), p);
	    }
	  printf ("%0o", st.st_mode & mask);
	}
      else if (strcmp (p, "nlink") == 0)
	printf ("%lu", (unsigned long) st.st_nlink);
      else if (strcmp (p, "uid") == 0)
	printf ("%ld", (long unsigned) st.st_uid);
      else if (strcmp (p, "gid") == 0)
	printf ("%lu", (unsigned long) st.st_gid);
      else if (strcmp (p, "size") == 0)
	printf ("%s", umaxtostr (st.st_size, buf));
      else if (strcmp (p, "blksize") == 0)
	printf ("%s", umaxtostr (st.st_blksize, buf));
      else if (strcmp (p, "blocks") == 0)
	printf ("%s", umaxtostr (st.st_blocks, buf));
      else if (strcmp (p, "atime") == 0)
	printf ("%lu", (unsigned long) st.st_atime);
      else if (strcmp (p, "atimeH") == 0)
	print_time (st.st_atime);
      else if (strcmp (p, "mtime") == 0)
	printf ("%lu", (unsigned long) st.st_mtime);
      else if (strcmp (p, "mtimeH") == 0)
	print_time (st.st_mtime);
      else if (strcmp (p, "ctime") == 0)
	printf ("%lu", (unsigned long) st.st_ctime);
      else if (strcmp (p, "ctimeH") == 0)
	print_time (st.st_ctime);
      else if (strcmp (p, "sparse") == 0)
	printf ("%d", ST_IS_SPARSE (st));
      else
	{
	  printf ("\n");
	  error (EXIT_FAILURE, 0, _("Unknown field `%s'"), p);
	}
      p = strtok (NULL, ",");
      if (p)
	printf (" ");
    }
  printf ("\n");
  free (fmt);
}


/* Exec Mode */

void
exec_checkpoint (struct action *p)
{
  if (verbose)
    printf ("processing checkpoint %lu\n", (unsigned long) p->checkpoint);
  switch (p->action)
    {
    case OPT_TOUCH:
      {
	struct timespec ts[2];

	ts[0] = ts[1] = p->ts;
	if (utimens (p->name, ts) != 0)
	  {
	    error (0, errno, _("cannot set time on `%s'"), p->name);
	    break;
	  }
      }
      break;

    case OPT_APPEND:
      {
	FILE *fp = fopen (p->name, "ab");
	if (!fp)
	  {
	    error (0, errno, _("cannot open `%s'"), p->name);
	    break;
	  }

	fill (fp, p->size, p->pattern);
	fclose (fp);
      }
      break;

    case OPT_TRUNCATE:
      {
	int fd = open (p->name, O_RDWR | O_BINARY);
	if (fd == -1)
	  {
	    error (0, errno, _("cannot open `%s'"), p->name);
	    break;
	  }
	ftruncate (fd, p->size);
	close (fd);
      }
      break;

    case OPT_EXEC:
      system (p->name);
      break;

    default:
      abort ();
    }
}

void
process_checkpoint (size_t n)
{
  struct action *p, *prev = NULL;

  for (p = action_list; p; )
    {
      struct action *next = p->next;

      if (p->checkpoint <= n)
	{
	  exec_checkpoint (p);
	  /* Remove the item from the list */
	  if (prev)
	    prev->next = next;
	  else
	    action_list = next;
	  free (p);
	}
      else
	prev = p;

      p = next;
    }
}

#define CHECKPOINT_TEXT "Write checkpoint"

void
exec_command (void)
{
  int status;
  pid_t pid;
  int fd[2];
  char *p;
  FILE *fp;
  char buf[128];

  /* Insert --checkpoint option.
     FIXME: This assumes that exec_argv does not use traditional tar options
     (without dash) */
  exec_argc++;
  exec_argv = xrealloc (exec_argv, (exec_argc + 1) * sizeof (*exec_argv));
  memmove (exec_argv+2, exec_argv+1, (exec_argc - 1) * sizeof (*exec_argv));
  exec_argv[1] = "--checkpoint";

#ifdef SIGCHLD
  /* System V fork+wait does not work if SIGCHLD is ignored.  */
  signal (SIGCHLD, SIG_DFL);
#endif

  pipe (fd);

  pid = fork ();
  if (pid == -1)
    error (EXIT_FAILURE, errno, "fork");

  if (pid == 0)
    {
      /* Child */

      /* Pipe stderr */
      if (fd[1] != 2)
	dup2 (fd[1], 2);
      close (fd[0]);

      /* Make sure POSIX locale is used */
      setenv ("LC_ALL", "POSIX", 1);

      execvp (exec_argv[0], exec_argv);
      error (EXIT_FAILURE, errno, "execvp");
    }

  /* Master */
  close (fd[1]);
  fp = fdopen (fd[0], "rb");
  if (fp == NULL)
    error (EXIT_FAILURE, errno, "fdopen");

  while ((p = fgets (buf, sizeof buf, fp)))
    {
      while (*p && !isspace (*p) && *p != ':')
	p++;

      if (*p == ':')
	{
	  for (p++; *p && isspace (*p); p++)
	    ;

	  if (*p
	      && memcmp (p, CHECKPOINT_TEXT, sizeof CHECKPOINT_TEXT - 1) == 0)
	    {
	      char *end;
	      size_t n = strtoul (p + sizeof CHECKPOINT_TEXT - 1, &end, 10);
	      if (!(*end && !isspace (*end)))
		{
		  process_checkpoint (n);
		  continue;
		}
	    }
	}
      fprintf (stderr, "%s", buf);
    }

  /* Collect exit status */
  waitpid (pid, &status, 0);

  if (verbose)
    {
      if (WIFEXITED (status))
	{
	  if (WEXITSTATUS (status) == 0)
	    printf (_("Command exited successfully\n"));
	  else
	    printf (_("Command failed with status %d\n"),
		    WEXITSTATUS (status));
	}
      else if (WIFSIGNALED (status))
	printf (_("Command terminated on signal %d\n"), WTERMSIG (status));
      else if (WIFSTOPPED (status))
	printf (_("Command stopped on signal %d\n"), WSTOPSIG (status));
#ifdef WCOREDUMP
      else if (WCOREDUMP (status))
	printf (_("Command dumped core\n"));
#endif
      else
	printf(_("Command terminated\n"));
    }

  if (WIFEXITED (status))
    exit (WEXITSTATUS (status));
  exit (EXIT_FAILURE);
}

int
main (int argc, char **argv)
{
  int index;

  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  get_date (&touch_time, "now", NULL);

  /* Decode command options.  */

  if (argp_parse (&argp, argc, argv, 0, &index, NULL))
    exit (EXIT_FAILURE);

  argc -= index;
  argv += index;

  switch (mode)
    {
    case mode_stat:
      if (argc == 0)
	error (EXIT_FAILURE, 0, _("--stat requires file names"));

      while (argc--)
	print_stat (*argv++);
      break;

    case mode_sparse:
      generate_sparse_file (argc, argv);
      verify_file (file_name);
      break;

    case mode_generate:
      if (argc)
	error (EXIT_FAILURE, 0, _("too many arguments"));
      if (files_from)
	generate_files_from_list ();
      else
	{
	  generate_simple_file (file_name);
	  verify_file (file_name);
	}
      break;

    case mode_exec:
      exec_command ();
      break;

    default:
      /* Just in case */
      abort ();
    }
  exit (EXIT_SUCCESS);
}