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+/* Functions for communicating with a remote tape drive.
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+ Copyright (C) 1988, 1992 Free Software Foundation, Inc.
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+
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+ This program is free software; you can redistribute it and/or modify
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+ it under the terms of the GNU General Public License as published by
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+ the Free Software Foundation; either version 2, or (at your option)
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+ any later version.
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+
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+ This program is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ GNU General Public License for more details.
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+
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+ You should have received a copy of the GNU General Public License
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+ along with this program; if not, write to the Free Software
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+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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+
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+/* The man page rmt(8) for /etc/rmt documents the remote mag tape
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+ protocol which rdump and rrestore use. Unfortunately, the man
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+ page is *WRONG*. The author of the routines I'm including originally
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+ wrote his code just based on the man page, and it didn't work, so he
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+ went to the rdump source to figure out why. The only thing he had to
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+ change was to check for the 'F' return code in addition to the 'E',
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+ and to separate the various arguments with \n instead of a space. I
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+ personally don't think that this is much of a problem, but I wanted to
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+ point it out. -- Arnold Robbins
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+
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+ Originally written by Jeff Lee, modified some by Arnold Robbins.
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+ Redone as a library that can replace open, read, write, etc., by
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+ Fred Fish, with some additional work by Arnold Robbins.
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+ Modified to make all rmtXXX calls into macros for speed by Jay Fenlason.
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+ Use -DUSE_REXEC for rexec code, courtesy of Dan Kegel, srs!dan. */
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+
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+#include <stdio.h>
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+#include <sys/types.h>
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+#include <signal.h>
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+
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+#ifndef NO_MTIO
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+#include <sys/ioctl.h>
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+#include <sys/mtio.h>
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+#endif
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+
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+#ifdef USE_REXEC
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+#include <netdb.h>
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+#endif
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+
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+#include <errno.h>
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+#include <setjmp.h>
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+#include <sys/stat.h>
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+
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+#ifndef errno
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+extern int errno;
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+#endif
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+
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+/* Maximum size of a fully qualified host name. */
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+#define MAXHOSTLEN 257
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+
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+/* Size of buffers for reading and writing commands to rmt.
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+ (An arbitrary limit.) */
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+#define CMDBUFSIZE 64
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+
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+#ifndef RETSIGTYPE
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+#define RETSIGTYPE void
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+#endif
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+
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+/* Maximum number of simultaneous remote tape connections.
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+ (Another arbitrary limit.) */
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+#define MAXUNIT 4
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+
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+/* Return the parent's read side of remote tape connection FILDES. */
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+#define READ(fildes) (from_rmt[fildes][0])
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+
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+/* Return the parent's write side of remote tape connection FILDES. */
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+#define WRITE(fildes) (to_rmt[fildes][1])
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+
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+/* The pipes for receiving data from remote tape drives. */
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+static int from_rmt[MAXUNIT][2] = {-1, -1, -1, -1, -1, -1, -1, -1};
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+
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+/* The pipes for sending data to remote tape drives. */
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+static int to_rmt[MAXUNIT][2] = {-1, -1, -1, -1, -1, -1, -1, -1};
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+
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+/* Temporary variable used by macros in rmt.h. */
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+char *__rmt_path;
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+
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+/* Close remote tape connection FILDES. */
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+
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+static void
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+_rmt_shutdown (fildes)
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+ int fildes;
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+{
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+ close (READ (fildes));
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+ close (WRITE (fildes));
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+ READ (fildes) = -1;
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+ WRITE (fildes) = -1;
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+}
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+
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+/* Attempt to perform the remote tape command specified in BUF
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+ on remote tape connection FILDES.
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+ Return 0 if successful, -1 on error. */
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+
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+static int
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+command (fildes, buf)
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+ int fildes;
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+ char *buf;
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+{
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+ register int buflen;
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+ RETSIGTYPE (*pipe_handler) ();
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+
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+ /* Save the current pipe handler and try to make the request. */
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+
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+ pipe_handler = signal (SIGPIPE, SIG_IGN);
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+ buflen = strlen (buf);
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+ if (write (WRITE (fildes), buf, buflen) == buflen)
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+ {
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+ signal (SIGPIPE, pipe_handler);
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+ return 0;
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+ }
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+
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+ /* Something went wrong. Close down and go home. */
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+
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+ signal (SIGPIPE, pipe_handler);
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+ _rmt_shutdown (fildes);
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+ errno = EIO;
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+ return -1;
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+}
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+
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+/* Read and return the status from remote tape connection FILDES.
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+ If an error occurred, return -1 and set errno. */
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+
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+static int
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+status (fildes)
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+ int fildes;
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+{
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+ int i;
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+ char c, *cp;
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+ char buffer[CMDBUFSIZE];
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+
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+ /* Read the reply command line. */
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+
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+ for (i = 0, cp = buffer; i < CMDBUFSIZE; i++, cp++)
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+ {
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+ if (read (READ (fildes), cp, 1) != 1)
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+ {
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+ _rmt_shutdown (fildes);
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+ errno = EIO;
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+ return -1;
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+ }
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+ if (*cp == '\n')
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+ {
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+ *cp = '\0';
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+ break;
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+ }
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+ }
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+
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+ if (i == CMDBUFSIZE)
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+ {
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+ _rmt_shutdown (fildes);
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+ errno = EIO;
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+ return -1;
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+ }
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+
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+ /* Check the return status. */
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+
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+ for (cp = buffer; *cp; cp++)
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+ if (*cp != ' ')
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+ break;
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+
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+ if (*cp == 'E' || *cp == 'F')
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+ {
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+ errno = atoi (cp + 1);
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+ /* Skip the error message line. */
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+ while (read (READ (fildes), &c, 1) == 1)
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+ if (c == '\n')
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+ break;
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+
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+ if (*cp == 'F')
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+ _rmt_shutdown (fildes);
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+
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+ return -1;
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+ }
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+
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+ /* Check for mis-synced pipes. */
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+
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+ if (*cp != 'A')
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+ {
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+ _rmt_shutdown (fildes);
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+ errno = EIO;
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+ return -1;
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+ }
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+
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+ /* Got an `A' (success) response. */
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+ return atoi (cp + 1);
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+}
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+
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+#ifdef USE_REXEC
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+/* Execute /etc/rmt as user USER on remote system HOST using rexec.
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+ Return a file descriptor of a bidirectional socket for stdin and stdout.
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+ If USER is NULL, or an empty string, use the current username.
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+
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+ By default, this code is not used, since it requires that
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+ the user have a .netrc file in his/her home directory, or that the
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+ application designer be willing to have rexec prompt for login and
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+ password info. This may be unacceptable, and .rhosts files for use
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+ with rsh are much more common on BSD systems. */
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+
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+static int
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+_rmt_rexec (host, user)
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+ char *host;
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+ char *user;
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+{
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+ struct servent *rexecserv;
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+ int save_stdin = dup (fileno (stdin));
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+ int save_stdout = dup (fileno (stdout));
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+ int tape_fd; /* Return value. */
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+
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+ /* When using cpio -o < filename, stdin is no longer the tty.
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+ But the rexec subroutine reads the login and the passwd on stdin,
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+ to allow remote execution of the command.
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+ So, reopen stdin and stdout on /dev/tty before the rexec and
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+ give them back their original value after. */
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+ if (freopen ("/dev/tty", "r", stdin) == NULL)
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+ freopen ("/dev/null", "r", stdin);
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+ if (freopen ("/dev/tty", "w", stdout) == NULL)
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+ freopen ("/dev/null", "w", stdout);
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+
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+ rexecserv = getservbyname ("exec", "tcp");
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+ if (NULL == rexecserv)
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+ {
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+ fprintf (stderr, "exec/tcp: service not available");
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+ exit (1);
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+ }
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+ if (user != NULL && *user == '\0')
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+ user = NULL;
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+ tape_fd = rexec (&host, rexecserv->s_port, user, NULL,
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+ "/etc/rmt", (int *) NULL);
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+ fclose (stdin);
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+ fdopen (save_stdin, "r");
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+ fclose (stdout);
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+ fdopen (save_stdout, "w");
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+
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+ return tape_fd;
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+}
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+#endif /* USE_REXEC */
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+
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+/* Open a magtape device on the system specified in PATH, as the given user.
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+ PATH has the form `[user@]system:/dev/????'.
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+ If COMPAT is defined, it can also have the form `system[.user]:/dev/????'.
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+
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+ OFLAG is O_RDONLY, O_WRONLY, etc.
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+ MODE is ignored; 0666 is always used.
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+
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+ If successful, return the remote tape pipe number plus BIAS.
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+ On error, return -1. */
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+
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+int
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+__rmt_open (path, oflag, mode, bias)
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+ char *path;
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+ int oflag;
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+ int mode;
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+ int bias;
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+{
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+ int i, rc;
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+ char buffer[CMDBUFSIZE]; /* Command buffer. */
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+ char system[MAXHOSTLEN]; /* The remote host name. */
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+ char device[CMDBUFSIZE]; /* The remote device name. */
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+ char login[CMDBUFSIZE]; /* The remote user name. */
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+ char *sys, *dev, *user; /* For copying into the above buffers. */
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+
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+ sys = system;
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+ dev = device;
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+ user = login;
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+
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+ /* Find an unused pair of file descriptors. */
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+
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+ for (i = 0; i < MAXUNIT; i++)
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+ if (READ (i) == -1 && WRITE (i) == -1)
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+ break;
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+
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+ if (i == MAXUNIT)
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+ {
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+ errno = EMFILE;
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+ return -1;
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+ }
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+
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+ /* Pull apart the system and device, and optional user.
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+ Don't munge the original string. */
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+
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+ while (*path != '@'
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+#ifdef COMPAT
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+ && *path != '.'
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+#endif
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+ && *path != ':')
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+ {
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+ *sys++ = *path++;
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+ }
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+ *sys = '\0';
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+ path++;
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+
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+ if (*(path - 1) == '@')
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+ {
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+ /* Saw user part of user@host. Start over. */
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+ strcpy (user, system);
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+ sys = system;
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+ while (*path != ':')
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+ {
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+ *sys++ = *path++;
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+ }
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+ *sys = '\0';
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+ path++;
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+ }
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+#ifdef COMPAT
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+ else if (*(path - 1) == '.')
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+ {
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+ while (*path != ':')
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+ {
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+ *user++ = *path++;
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+ }
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+ *user = '\0';
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+ path++;
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+ }
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+#endif
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+ else
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+ *user = '\0';
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+
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+ while (*path)
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+ {
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+ *dev++ = *path++;
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+ }
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+ *dev = '\0';
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+
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+#ifdef USE_REXEC
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+ /* Execute the remote command using rexec. */
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+ READ (i) = WRITE (i) = _rmt_rexec (system, login);
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+ if (READ (i) < 0)
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+ return -1;
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+#else /* !USE_REXEC */
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+ /* Set up the pipes for the `rsh' command, and fork. */
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+
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+ if (pipe (to_rmt[i]) == -1 || pipe (from_rmt[i]) == -1)
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+ return -1;
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+
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+ rc = fork ();
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+ if (rc == -1)
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+ return -1;
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+
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+ if (rc == 0)
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+ {
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+ /* Child. */
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+ close (0);
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+ dup (to_rmt[i][0]);
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+ close (to_rmt[i][0]);
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+ close (to_rmt[i][1]);
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+
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+ close (1);
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+ dup (from_rmt[i][1]);
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+ close (from_rmt[i][0]);
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+ close (from_rmt[i][1]);
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+
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+ setuid (getuid ());
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+ setgid (getgid ());
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+
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+ if (*login)
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+ {
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+ execl ("/usr/ucb/rsh", "rsh", system, "-l", login,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/remsh", "remsh", system, "-l", login,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/rsh", "rsh", system, "-l", login,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bsd/rsh", "rsh", system, "-l", login,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/nsh", "nsh", system, "-l", login,
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+ "/etc/rmt", (char *) 0);
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+ }
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+ else
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+ {
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+ execl ("/usr/ucb/rsh", "rsh", system,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/remsh", "remsh", system,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/rsh", "rsh", system,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bsd/rsh", "rsh", system,
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+ "/etc/rmt", (char *) 0);
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+ execl ("/usr/bin/nsh", "nsh", system,
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+ "/etc/rmt", (char *) 0);
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+ }
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+
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+ /* Bad problems if we get here. */
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+
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+ perror ("cannot execute remote shell");
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+ _exit (1);
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+ }
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+
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+ /* Parent. */
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+ close (to_rmt[i][0]);
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+ close (from_rmt[i][1]);
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+#endif /* !USE_REXEC */
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+
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+ /* Attempt to open the tape device. */
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+
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+ sprintf (buffer, "O%s\n%d\n", device, oflag);
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+ if (command (i, buffer) == -1 || status (i) == -1)
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+ return -1;
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+
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+ return i + bias;
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+}
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+
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+/* Close remote tape connection FILDES and shut down.
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+ Return 0 if successful, -1 on error. */
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+
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+int
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+__rmt_close (fildes)
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+ int fildes;
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+{
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+ int rc;
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+
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+ if (command (fildes, "C\n") == -1)
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+ return -1;
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+
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+ rc = status (fildes);
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+ _rmt_shutdown (fildes);
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+ return rc;
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+}
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+
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+/* Read up to NBYTE bytes into BUF from remote tape connection FILDES.
|
|
|
+ Return the number of bytes read on success, -1 on error. */
|
|
|
+
|
|
|
+int
|
|
|
+__rmt_read (fildes, buf, nbyte)
|
|
|
+ int fildes;
|
|
|
+ char *buf;
|
|
|
+ unsigned int nbyte;
|
|
|
+{
|
|
|
+ int rc, i;
|
|
|
+ char buffer[CMDBUFSIZE];
|
|
|
+
|
|
|
+ sprintf (buffer, "R%d\n", nbyte);
|
|
|
+ if (command (fildes, buffer) == -1 || (rc = status (fildes)) == -1)
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ for (i = 0; i < rc; i += nbyte, buf += nbyte)
|
|
|
+ {
|
|
|
+ nbyte = read (READ (fildes), buf, rc);
|
|
|
+ if (nbyte <= 0)
|
|
|
+ {
|
|
|
+ _rmt_shutdown (fildes);
|
|
|
+ errno = EIO;
|
|
|
+ return -1;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ return rc;
|
|
|
+}
|
|
|
+
|
|
|
+/* Write NBYTE bytes from BUF to remote tape connection FILDES.
|
|
|
+ Return the number of bytes written on success, -1 on error. */
|
|
|
+
|
|
|
+int
|
|
|
+__rmt_write (fildes, buf, nbyte)
|
|
|
+ int fildes;
|
|
|
+ char *buf;
|
|
|
+ unsigned int nbyte;
|
|
|
+{
|
|
|
+ char buffer[CMDBUFSIZE];
|
|
|
+ RETSIGTYPE (*pipe_handler) ();
|
|
|
+
|
|
|
+ sprintf (buffer, "W%d\n", nbyte);
|
|
|
+ if (command (fildes, buffer) == -1)
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ pipe_handler = signal (SIGPIPE, SIG_IGN);
|
|
|
+ if (write (WRITE (fildes), buf, nbyte) == nbyte)
|
|
|
+ {
|
|
|
+ signal (SIGPIPE, pipe_handler);
|
|
|
+ return status (fildes);
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Write error. */
|
|
|
+ signal (SIGPIPE, pipe_handler);
|
|
|
+ _rmt_shutdown (fildes);
|
|
|
+ errno = EIO;
|
|
|
+ return -1;
|
|
|
+}
|
|
|
+
|
|
|
+/* Perform an imitation lseek operation on remote tape connection FILDES.
|
|
|
+ Return the new file offset if successful, -1 if on error. */
|
|
|
+
|
|
|
+long
|
|
|
+__rmt_lseek (fildes, offset, whence)
|
|
|
+ int fildes;
|
|
|
+ long offset;
|
|
|
+ int whence;
|
|
|
+{
|
|
|
+ char buffer[CMDBUFSIZE];
|
|
|
+
|
|
|
+ sprintf (buffer, "L%ld\n%d\n", offset, whence);
|
|
|
+ if (command (fildes, buffer) == -1)
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ return status (fildes);
|
|
|
+}
|
|
|
+
|
|
|
+/* Perform a raw tape operation on remote tape connection FILDES.
|
|
|
+ Return the results of the ioctl, or -1 on error. */
|
|
|
+
|
|
|
+#ifndef NO_MTIO
|
|
|
+__rmt_ioctl (fildes, op, arg)
|
|
|
+ int fildes, op;
|
|
|
+ char *arg;
|
|
|
+{
|
|
|
+ char c;
|
|
|
+ int rc, cnt;
|
|
|
+ char buffer[CMDBUFSIZE];
|
|
|
+
|
|
|
+ switch (op)
|
|
|
+ {
|
|
|
+ default:
|
|
|
+ errno = EINVAL;
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ case MTIOCTOP:
|
|
|
+ /* MTIOCTOP is the easy one. Nothing is transfered in binary. */
|
|
|
+ sprintf (buffer, "I%d\n%d\n", ((struct mtop *) arg)->mt_op,
|
|
|
+ ((struct mtop *) arg)->mt_count);
|
|
|
+ if (command (fildes, buffer) == -1)
|
|
|
+ return -1;
|
|
|
+ return status (fildes); /* Return the count. */
|
|
|
+
|
|
|
+ case MTIOCGET:
|
|
|
+ /* Grab the status and read it directly into the structure.
|
|
|
+ This assumes that the status buffer is not padded
|
|
|
+ and that 2 shorts fit in a long without any word
|
|
|
+ alignment problems; i.e., the whole struct is contiguous.
|
|
|
+ NOTE - this is probably NOT a good assumption. */
|
|
|
+
|
|
|
+ if (command (fildes, "S") == -1 || (rc = status (fildes)) == -1)
|
|
|
+ return -1;
|
|
|
+
|
|
|
+ for (; rc > 0; rc -= cnt, arg += cnt)
|
|
|
+ {
|
|
|
+ cnt = read (READ (fildes), arg, rc);
|
|
|
+ if (cnt <= 0)
|
|
|
+ {
|
|
|
+ _rmt_shutdown (fildes);
|
|
|
+ errno = EIO;
|
|
|
+ return -1;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ /* Check for byte position. mt_type is a small integer field
|
|
|
+ (normally) so we will check its magnitude. If it is larger than
|
|
|
+ 256, we will assume that the bytes are swapped and go through
|
|
|
+ and reverse all the bytes. */
|
|
|
+
|
|
|
+ if (((struct mtget *) arg)->mt_type < 256)
|
|
|
+ return 0;
|
|
|
+
|
|
|
+ for (cnt = 0; cnt < rc; cnt += 2)
|
|
|
+ {
|
|
|
+ c = arg[cnt];
|
|
|
+ arg[cnt] = arg[cnt + 1];
|
|
|
+ arg[cnt + 1] = c;
|
|
|
+ }
|
|
|
+
|
|
|
+ return 0;
|
|
|
+ }
|
|
|
+}
|
|
|
+#endif /* NO_MTIO */
|