741 lines
19 KiB
C
741 lines
19 KiB
C
/* Functions for communicating with a remote tape drive.
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Copyright 1988, 1992, 1994, 1996, 1997, 1999, 2000, 2001, 2004 Free
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Software Foundation, Inc.
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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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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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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 Foundation,
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Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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/* The man page rmt(8) for /etc/rmt documents the remote mag tape protocol
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which rdump and rrestore use. Unfortunately, the man page is *WRONG*.
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The author of the routines I'm including originally wrote his code just
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based on the man page, and it didn't work, so he went to the rdump source
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to figure out why. The only thing he had to change was to check for the
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'F' return code in addition to the 'E', and to separate the various
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arguments with \n instead of a space. I personally don't think that this
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is much of a problem, but I wanted to point it out. -- Arnold Robbins
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Originally written by Jeff Lee, modified some by Arnold Robbins. Redone
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as a library that can replace open, read, write, etc., by Fred Fish, with
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some additional work by Arnold Robbins. Modified to make all rmt* calls
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into macros for speed by Jay Fenlason. Use -DWITH_REXEC for rexec
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code, courtesy of Dan Kegel. */
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#include "system.h"
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#include <safe-read.h>
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#include <full-write.h>
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/* Try hard to get EOPNOTSUPP defined. 486/ISC has it in net/errno.h,
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3B2/SVR3 has it in sys/inet.h. Otherwise, like on MSDOS, use EINVAL. */
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#ifndef EOPNOTSUPP
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# if HAVE_NET_ERRNO_H
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# include <net/errno.h>
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# endif
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# if HAVE_SYS_INET_H
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# include <sys/inet.h>
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# endif
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# ifndef EOPNOTSUPP
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# define EOPNOTSUPP EINVAL
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# endif
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#endif
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#include <signal.h>
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#if HAVE_NETDB_H
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# include <netdb.h>
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#endif
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#include <rmt.h>
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#include <localedir.h>
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/* Exit status if exec errors. */
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#define EXIT_ON_EXEC_ERROR 128
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/* FIXME: Size of buffers for reading and writing commands to rmt. */
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#define COMMAND_BUFFER_SIZE 64
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#ifndef RETSIGTYPE
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# define RETSIGTYPE void
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#endif
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/* FIXME: Maximum number of simultaneous remote tape connections. */
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#define MAXUNIT 4
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#define PREAD 0 /* read file descriptor from pipe() */
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#define PWRITE 1 /* write file descriptor from pipe() */
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/* Return the parent's read side of remote tape connection Fd. */
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#define READ_SIDE(Fd) (from_remote[Fd][PREAD])
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/* Return the parent's write side of remote tape connection Fd. */
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#define WRITE_SIDE(Fd) (to_remote[Fd][PWRITE])
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/* The pipes for receiving data from remote tape drives. */
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static int from_remote[MAXUNIT][2] = {{-1, -1}, {-1, -1}, {-1, -1}, {-1, -1}};
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/* The pipes for sending data to remote tape drives. */
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static int to_remote[MAXUNIT][2] = {{-1, -1}, {-1, -1}, {-1, -1}, {-1, -1}};
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char *rmt_command = DEFAULT_RMT_COMMAND;
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/* Temporary variable used by macros in rmt.h. */
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char *rmt_dev_name__;
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/* If true, always consider file names to be local, even if they contain
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colons */
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bool force_local_option;
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/* Close remote tape connection HANDLE, and reset errno to ERRNO_VALUE. */
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static void
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_rmt_shutdown (int handle, int errno_value)
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{
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close (READ_SIDE (handle));
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close (WRITE_SIDE (handle));
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READ_SIDE (handle) = -1;
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WRITE_SIDE (handle) = -1;
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errno = errno_value;
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}
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/* Attempt to perform the remote tape command specified in BUFFER on
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remote tape connection HANDLE. Return 0 if successful, -1 on
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error. */
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static int
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do_command (int handle, const char *buffer)
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{
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/* Save the current pipe handler and try to make the request. */
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size_t length = strlen (buffer);
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RETSIGTYPE (*pipe_handler) () = signal (SIGPIPE, SIG_IGN);
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ssize_t written = full_write (WRITE_SIDE (handle), buffer, length);
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signal (SIGPIPE, pipe_handler);
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if (written == length)
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return 0;
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/* Something went wrong. Close down and go home. */
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_rmt_shutdown (handle, EIO);
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return -1;
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}
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static char *
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get_status_string (int handle, char *command_buffer)
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{
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char *cursor;
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int counter;
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/* Read the reply command line. */
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for (counter = 0, cursor = command_buffer;
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counter < COMMAND_BUFFER_SIZE;
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counter++, cursor++)
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{
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if (safe_read (READ_SIDE (handle), cursor, 1) != 1)
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{
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_rmt_shutdown (handle, EIO);
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return 0;
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}
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if (*cursor == '\n')
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{
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*cursor = '\0';
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break;
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}
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}
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if (counter == COMMAND_BUFFER_SIZE)
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{
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_rmt_shutdown (handle, EIO);
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return 0;
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}
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/* Check the return status. */
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for (cursor = command_buffer; *cursor; cursor++)
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if (*cursor != ' ')
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break;
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if (*cursor == 'E' || *cursor == 'F')
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{
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/* Skip the error message line. */
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/* FIXME: there is better to do than merely ignoring error messages
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coming from the remote end. Translate them, too... */
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{
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char character;
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while (safe_read (READ_SIDE (handle), &character, 1) == 1)
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if (character == '\n')
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break;
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}
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errno = atoi (cursor + 1);
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if (*cursor == 'F')
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_rmt_shutdown (handle, errno);
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return 0;
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}
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/* Check for mis-synced pipes. */
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if (*cursor != 'A')
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{
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_rmt_shutdown (handle, EIO);
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return 0;
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}
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/* Got an `A' (success) response. */
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return cursor + 1;
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}
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/* Read and return the status from remote tape connection HANDLE. If
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an error occurred, return -1 and set errno. */
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static long int
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get_status (int handle)
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{
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char command_buffer[COMMAND_BUFFER_SIZE];
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const char *status = get_status_string (handle, command_buffer);
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if (status)
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{
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long int result = atol (status);
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if (0 <= result)
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return result;
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errno = EIO;
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}
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return -1;
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}
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static off_t
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get_status_off (int handle)
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{
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char command_buffer[COMMAND_BUFFER_SIZE];
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const char *status = get_status_string (handle, command_buffer);
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if (! status)
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return -1;
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else
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{
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/* Parse status, taking care to check for overflow.
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We can't use standard functions,
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since off_t might be longer than long. */
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off_t count = 0;
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int negative;
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for (; *status == ' ' || *status == '\t'; status++)
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continue;
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negative = *status == '-';
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status += negative || *status == '+';
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for (;;)
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{
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int digit = *status++ - '0';
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if (9 < (unsigned) digit)
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break;
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else
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{
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off_t c10 = 10 * count;
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off_t nc = negative ? c10 - digit : c10 + digit;
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if (c10 / 10 != count || (negative ? c10 < nc : nc < c10))
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return -1;
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count = nc;
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}
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}
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return count;
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}
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}
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#if WITH_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
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stdout. If USER is zero, use the current username.
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By default, this code is not used, since it requires that the user
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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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static int
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_rmt_rexec (char *host, char *user)
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{
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int saved_stdin = dup (STDIN_FILENO);
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int saved_stdout = dup (STDOUT_FILENO);
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struct servent *rexecserv;
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int result;
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/* When using cpio -o < filename, stdin is no longer the tty. But the
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rexec subroutine reads the login and the passwd on stdin, to allow
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remote execution of the command. So, reopen stdin and stdout on
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/dev/tty before the rexec and give them back their original value
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after. */
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if (! freopen ("/dev/tty", "r", stdin))
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freopen ("/dev/null", "r", stdin);
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if (! freopen ("/dev/tty", "w", stdout))
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freopen ("/dev/null", "w", stdout);
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if (rexecserv = getservbyname ("exec", "tcp"), !rexecserv)
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error (EXIT_ON_EXEC_ERROR, 0, _("exec/tcp: Service not available"));
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result = rexec (&host, rexecserv->s_port, user, 0, rmt_command, 0);
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if (fclose (stdin) == EOF)
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error (0, errno, _("stdin"));
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fdopen (saved_stdin, "r");
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if (fclose (stdout) == EOF)
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error (0, errno, _("stdout"));
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fdopen (saved_stdout, "w");
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return result;
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}
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#endif /* WITH_REXEC */
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/* Place into BUF a string representing OFLAG, which must be suitable
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as argument 2 of `open'. BUF must be large enough to hold the
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result. This function should generate a string that decode_oflag
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can parse. */
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static void
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encode_oflag (char *buf, int oflag)
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{
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sprintf (buf, "%d ", oflag);
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switch (oflag & O_ACCMODE)
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{
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case O_RDONLY: strcat (buf, "O_RDONLY"); break;
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case O_RDWR: strcat (buf, "O_RDWR"); break;
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case O_WRONLY: strcat (buf, "O_WRONLY"); break;
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default: abort ();
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}
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#ifdef O_APPEND
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if (oflag & O_APPEND) strcat (buf, "|O_APPEND");
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#endif
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if (oflag & O_CREAT) strcat (buf, "|O_CREAT");
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#ifdef O_DSYNC
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if (oflag & O_DSYNC) strcat (buf, "|O_DSYNC");
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#endif
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if (oflag & O_EXCL) strcat (buf, "|O_EXCL");
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#ifdef O_LARGEFILE
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if (oflag & O_LARGEFILE) strcat (buf, "|O_LARGEFILE");
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#endif
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#ifdef O_NOCTTY
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if (oflag & O_NOCTTY) strcat (buf, "|O_NOCTTY");
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#endif
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#ifdef O_NONBLOCK
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if (oflag & O_NONBLOCK) strcat (buf, "|O_NONBLOCK");
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#endif
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#ifdef O_RSYNC
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if (oflag & O_RSYNC) strcat (buf, "|O_RSYNC");
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#endif
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#ifdef O_SYNC
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if (oflag & O_SYNC) strcat (buf, "|O_SYNC");
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#endif
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if (oflag & O_TRUNC) strcat (buf, "|O_TRUNC");
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}
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/* Open a file (a magnetic tape device?) on the system specified in
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FILE_NAME, as the given user. FILE_NAME has the form `[USER@]HOST:FILE'.
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OPEN_MODE is O_RDONLY, O_WRONLY, etc. If successful, return the
|
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remote pipe number plus BIAS. REMOTE_SHELL may be overridden. On
|
||
error, return -1. */
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int
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rmt_open__ (const char *file_name, int open_mode, int bias,
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const char *remote_shell)
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{
|
||
int remote_pipe_number; /* pseudo, biased file descriptor */
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||
char *file_name_copy; /* copy of file_name string */
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char *remote_host; /* remote host name */
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char *remote_file; /* remote file name (often a device) */
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||
char *remote_user; /* remote user name */
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||
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/* Find an unused pair of file descriptors. */
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||
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for (remote_pipe_number = 0;
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remote_pipe_number < MAXUNIT;
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remote_pipe_number++)
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if (READ_SIDE (remote_pipe_number) == -1
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&& WRITE_SIDE (remote_pipe_number) == -1)
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break;
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||
|
||
if (remote_pipe_number == MAXUNIT)
|
||
{
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errno = EMFILE;
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||
return -1;
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||
}
|
||
|
||
/* Pull apart the system and device, and optional user. */
|
||
|
||
{
|
||
char *cursor;
|
||
|
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file_name_copy = xstrdup (file_name);
|
||
remote_host = file_name_copy;
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||
remote_user = 0;
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remote_file = 0;
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||
|
||
for (cursor = file_name_copy; *cursor; cursor++)
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switch (*cursor)
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||
{
|
||
default:
|
||
break;
|
||
|
||
case '\n':
|
||
/* Do not allow newlines in the file_name, since the protocol
|
||
uses newline delimiters. */
|
||
free (file_name_copy);
|
||
errno = ENOENT;
|
||
return -1;
|
||
|
||
case '@':
|
||
if (!remote_user)
|
||
{
|
||
remote_user = remote_host;
|
||
*cursor = '\0';
|
||
remote_host = cursor + 1;
|
||
}
|
||
break;
|
||
|
||
case ':':
|
||
if (!remote_file)
|
||
{
|
||
*cursor = '\0';
|
||
remote_file = cursor + 1;
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* FIXME: Should somewhat validate the decoding, here. */
|
||
|
||
if (remote_user && *remote_user == '\0')
|
||
remote_user = 0;
|
||
|
||
#if WITH_REXEC
|
||
|
||
/* Execute the remote command using rexec. */
|
||
|
||
READ_SIDE (remote_pipe_number) = _rmt_rexec (remote_host, remote_user);
|
||
if (READ_SIDE (remote_pipe_number) < 0)
|
||
{
|
||
int e = errno;
|
||
free (file_name_copy);
|
||
errno = e;
|
||
return -1;
|
||
}
|
||
|
||
WRITE_SIDE (remote_pipe_number) = READ_SIDE (remote_pipe_number);
|
||
|
||
#else /* not WITH_REXEC */
|
||
{
|
||
const char *remote_shell_basename;
|
||
pid_t status;
|
||
|
||
/* Identify the remote command to be executed. */
|
||
|
||
if (!remote_shell)
|
||
{
|
||
#ifdef REMOTE_SHELL
|
||
remote_shell = REMOTE_SHELL;
|
||
#else
|
||
free (file_name_copy);
|
||
errno = EIO;
|
||
return -1;
|
||
#endif
|
||
}
|
||
remote_shell_basename = base_name (remote_shell);
|
||
|
||
/* Set up the pipes for the `rsh' command, and fork. */
|
||
|
||
if (pipe (to_remote[remote_pipe_number]) == -1
|
||
|| pipe (from_remote[remote_pipe_number]) == -1)
|
||
{
|
||
int e = errno;
|
||
free (file_name_copy);
|
||
errno = e;
|
||
return -1;
|
||
}
|
||
|
||
status = fork ();
|
||
if (status == -1)
|
||
{
|
||
int e = errno;
|
||
free (file_name_copy);
|
||
errno = e;
|
||
return -1;
|
||
}
|
||
|
||
if (status == 0)
|
||
{
|
||
/* Child. */
|
||
|
||
close (STDIN_FILENO);
|
||
dup (to_remote[remote_pipe_number][PREAD]);
|
||
close (to_remote[remote_pipe_number][PREAD]);
|
||
close (to_remote[remote_pipe_number][PWRITE]);
|
||
|
||
close (STDOUT_FILENO);
|
||
dup (from_remote[remote_pipe_number][PWRITE]);
|
||
close (from_remote[remote_pipe_number][PREAD]);
|
||
close (from_remote[remote_pipe_number][PWRITE]);
|
||
|
||
sys_reset_uid_gid ();
|
||
|
||
if (remote_user)
|
||
execl (remote_shell, remote_shell_basename, remote_host,
|
||
"-l", remote_user, rmt_command, (char *) 0);
|
||
else
|
||
execl (remote_shell, remote_shell_basename, remote_host,
|
||
rmt_command, (char *) 0);
|
||
|
||
/* Bad problems if we get here. */
|
||
|
||
/* In a previous version, _exit was used here instead of exit. */
|
||
error (EXIT_ON_EXEC_ERROR, errno, _("Cannot execute remote shell"));
|
||
}
|
||
|
||
/* Parent. */
|
||
|
||
close (from_remote[remote_pipe_number][PWRITE]);
|
||
close (to_remote[remote_pipe_number][PREAD]);
|
||
}
|
||
#endif /* not WITH_REXEC */
|
||
|
||
/* Attempt to open the tape device. */
|
||
|
||
{
|
||
size_t remote_file_len = strlen (remote_file);
|
||
char *command_buffer = xmalloc (remote_file_len + 1000);
|
||
sprintf (command_buffer, "O%s\n", remote_file);
|
||
encode_oflag (command_buffer + remote_file_len + 2, open_mode);
|
||
strcat (command_buffer, "\n");
|
||
if (do_command (remote_pipe_number, command_buffer) == -1
|
||
|| get_status (remote_pipe_number) == -1)
|
||
{
|
||
int e = errno;
|
||
free (command_buffer);
|
||
free (file_name_copy);
|
||
_rmt_shutdown (remote_pipe_number, e);
|
||
return -1;
|
||
}
|
||
free (command_buffer);
|
||
}
|
||
|
||
free (file_name_copy);
|
||
return remote_pipe_number + bias;
|
||
}
|
||
|
||
/* Close remote tape connection HANDLE and shut down. Return 0 if
|
||
successful, -1 on error. */
|
||
int
|
||
rmt_close__ (int handle)
|
||
{
|
||
long int status;
|
||
|
||
if (do_command (handle, "C\n") == -1)
|
||
return -1;
|
||
|
||
status = get_status (handle);
|
||
_rmt_shutdown (handle, errno);
|
||
return status;
|
||
}
|
||
|
||
/* Read up to LENGTH bytes into BUFFER from remote tape connection HANDLE.
|
||
Return the number of bytes read on success, SAFE_READ_ERROR on error. */
|
||
size_t
|
||
rmt_read__ (int handle, char *buffer, size_t length)
|
||
{
|
||
char command_buffer[COMMAND_BUFFER_SIZE];
|
||
size_t status;
|
||
size_t rlen;
|
||
size_t counter;
|
||
|
||
sprintf (command_buffer, "R%lu\n", (unsigned long) length);
|
||
if (do_command (handle, command_buffer) == -1
|
||
|| (status = get_status (handle)) == SAFE_READ_ERROR)
|
||
return SAFE_READ_ERROR;
|
||
|
||
for (counter = 0; counter < status; counter += rlen, buffer += rlen)
|
||
{
|
||
rlen = safe_read (READ_SIDE (handle), buffer, status - counter);
|
||
if (rlen == SAFE_READ_ERROR || rlen == 0)
|
||
{
|
||
_rmt_shutdown (handle, EIO);
|
||
return SAFE_READ_ERROR;
|
||
}
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
/* Write LENGTH bytes from BUFFER to remote tape connection HANDLE.
|
||
Return the number of bytes written. */
|
||
size_t
|
||
rmt_write__ (int handle, char *buffer, size_t length)
|
||
{
|
||
char command_buffer[COMMAND_BUFFER_SIZE];
|
||
RETSIGTYPE (*pipe_handler) ();
|
||
size_t written;
|
||
|
||
sprintf (command_buffer, "W%lu\n", (unsigned long) length);
|
||
if (do_command (handle, command_buffer) == -1)
|
||
return 0;
|
||
|
||
pipe_handler = signal (SIGPIPE, SIG_IGN);
|
||
written = full_write (WRITE_SIDE (handle), buffer, length);
|
||
signal (SIGPIPE, pipe_handler);
|
||
if (written == length)
|
||
{
|
||
long int r = get_status (handle);
|
||
if (r < 0)
|
||
return 0;
|
||
if (r == length)
|
||
return length;
|
||
written = r;
|
||
}
|
||
|
||
/* Write error. */
|
||
|
||
_rmt_shutdown (handle, EIO);
|
||
return written;
|
||
}
|
||
|
||
/* Perform an imitation lseek operation on remote tape connection
|
||
HANDLE. Return the new file offset if successful, -1 if on error. */
|
||
off_t
|
||
rmt_lseek__ (int handle, off_t offset, int whence)
|
||
{
|
||
char command_buffer[COMMAND_BUFFER_SIZE];
|
||
char operand_buffer[UINTMAX_STRSIZE_BOUND];
|
||
uintmax_t u = offset < 0 ? - (uintmax_t) offset : (uintmax_t) offset;
|
||
char *p = operand_buffer + sizeof operand_buffer;
|
||
|
||
*--p = 0;
|
||
do
|
||
*--p = '0' + (int) (u % 10);
|
||
while ((u /= 10) != 0);
|
||
if (offset < 0)
|
||
*--p = '-';
|
||
|
||
switch (whence)
|
||
{
|
||
case SEEK_SET: whence = 0; break;
|
||
case SEEK_CUR: whence = 1; break;
|
||
case SEEK_END: whence = 2; break;
|
||
default: abort ();
|
||
}
|
||
|
||
sprintf (command_buffer, "L%s\n%d\n", p, whence);
|
||
|
||
if (do_command (handle, command_buffer) == -1)
|
||
return -1;
|
||
|
||
return get_status_off (handle);
|
||
}
|
||
|
||
/* Perform a raw tape operation on remote tape connection HANDLE.
|
||
Return the results of the ioctl, or -1 on error. */
|
||
int
|
||
rmt_ioctl__ (int handle, int operation, char *argument)
|
||
{
|
||
switch (operation)
|
||
{
|
||
default:
|
||
errno = EOPNOTSUPP;
|
||
return -1;
|
||
|
||
#ifdef MTIOCTOP
|
||
case MTIOCTOP:
|
||
{
|
||
char command_buffer[COMMAND_BUFFER_SIZE];
|
||
char operand_buffer[UINTMAX_STRSIZE_BOUND];
|
||
uintmax_t u = (((struct mtop *) argument)->mt_count < 0
|
||
? - (uintmax_t) ((struct mtop *) argument)->mt_count
|
||
: (uintmax_t) ((struct mtop *) argument)->mt_count);
|
||
char *p = operand_buffer + sizeof operand_buffer;
|
||
|
||
*--p = 0;
|
||
do
|
||
*--p = '0' + (int) (u % 10);
|
||
while ((u /= 10) != 0);
|
||
if (((struct mtop *) argument)->mt_count < 0)
|
||
*--p = '-';
|
||
|
||
/* MTIOCTOP is the easy one. Nothing is transferred in binary. */
|
||
|
||
sprintf (command_buffer, "I%d\n%s\n",
|
||
((struct mtop *) argument)->mt_op, p);
|
||
if (do_command (handle, command_buffer) == -1)
|
||
return -1;
|
||
|
||
return get_status (handle);
|
||
}
|
||
#endif /* MTIOCTOP */
|
||
|
||
#ifdef MTIOCGET
|
||
case MTIOCGET:
|
||
{
|
||
ssize_t status;
|
||
size_t counter;
|
||
|
||
/* 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 (do_command (handle, "S") == -1
|
||
|| (status = get_status (handle), status == -1))
|
||
return -1;
|
||
|
||
for (; status > 0; status -= counter, argument += counter)
|
||
{
|
||
counter = safe_read (READ_SIDE (handle), argument, status);
|
||
if (counter == SAFE_READ_ERROR || counter == 0)
|
||
{
|
||
_rmt_shutdown (handle, EIO);
|
||
return -1;
|
||
}
|
||
}
|
||
|
||
/* Check for byte position. mt_type (or mt_model) 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 *) argument)->MTIO_CHECK_FIELD < 256)
|
||
return 0;
|
||
|
||
for (counter = 0; counter < status; counter += 2)
|
||
{
|
||
char copy = argument[counter];
|
||
|
||
argument[counter] = argument[counter + 1];
|
||
argument[counter + 1] = copy;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
#endif /* MTIOCGET */
|
||
|
||
}
|
||
}
|