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- Subject: v18i109: Remote tape library
- Newsgroups: comp.sources.unix
- Sender: sources
- Approved: rsalz@uunet.UU.NET
-
- Submitted-by: arnold@emoryu1.cc.emory.edu (Arnold D. Robbins)
- Posting-number: Volume 18, Issue 109
- Archive-name: rmtlib2
-
- [ Needs for for non-BSD-dervied systems. --r$ ]
-
- This is the remote mag tape library. It allows a program that uses
- Unix system calls to transparently use a file (usually a tape drive) on
- another system via /etc/rmt, simply by including <rmt.h>. It is
- particularly useful with tar and dd, and is supplied with GNU tar.
-
- This package has evolved somewhat over the years. My thanks to the
- people who did most of the original work, and those who've contributed
- bug fixes; appropriate credit is in the man page and source files.
-
- Enjoy,
-
- Arnold Robbins
- Emory U. Computing Center
- arnold@emoryu1.cc.emory.edu
- gatech!emoryu1!arnold
-
- ----------------------------------------
- #! /bin/sh
- # This is a shell archive, meaning:
- # 1. Remove everything above the #! /bin/sh line.
- # 2. Save the resulting text in a file.
- # 3. Execute the file with /bin/sh (not csh) to create:
- # README
- # Makefile
- # rmt.h
- # rmtlib.c
- # rmtops.3
- export PATH; PATH=/bin:/usr/bin:$PATH
- echo shar: "extracting 'README'" '(602 characters)'
- if test -f 'README'
- then
- echo shar: "will not over-write existing file 'README'"
- else
- cat << \SHAR_EOF > 'README'
- README
-
- This is the remote mag tape library. It allows a program that uses
- Unix system calls to transparently use a file (usually a tape drive) on
- another system via /etc/rmt, simply by including <rmt.h>. It is
- particularly useful with tar and dd, and is supplied with GNU tar.
-
- This package has evolved somewhat over the years. My thanks to the
- people who did most of the original work, and those who've contributed
- bug fixes; appropriate credit is in the man page and source files.
-
- Enjoy,
-
- Arnold Robbins
- Emory U. Computing Center
- arnold@emoryu1.cc.emory.edu
- gatech!emoryu1!arnold
- +1 404 727 7636
- SHAR_EOF
- fi
- echo shar: "extracting 'Makefile'" '(421 characters)'
- if test -f 'Makefile'
- then
- echo shar: "will not over-write existing file 'Makefile'"
- else
- cat << \SHAR_EOF > 'Makefile'
- #
- # $Header: Makefile,v 1.1 86/10/09 16:42:13 root Locked $
- #
- # $Log: Makefile,v $
- # Revision 1.1 86/10/09 16:42:13 root
- # Initial revision
- #
- #
- # Makefile for rmtlib
-
- CFLAGS= -O
- SRC= rmtlib.c
- DOC= rmtops.3
-
- MANSEC=3
- DEST= /usr/lib
-
- librmt.a: rmtlib.o
- ar rv librmt.a rmtlib.o
-
- install: librmt.a
- cp librmt.a /usr/lib
- ranlib /usr/lib/librmt.a
- cp $(DOC) /usr/man/man$(MANSEC)/rmtops.$(MANSEC)
-
- clean:
- rm -f rmtlib.o
- SHAR_EOF
- fi
- echo shar: "extracting 'rmt.h'" '(1056 characters)'
- if test -f 'rmt.h'
- then
- echo shar: "will not over-write existing file 'rmt.h'"
- else
- cat << \SHAR_EOF > 'rmt.h'
- /*
- * $Header: rmt.h,v 1.1 86/10/09 16:17:20 root Locked $
- *
- * $Log: rmt.h,v $
- * Revision 1.1 86/10/09 16:17:20 root
- * Initial revision
- *
- */
-
- /*
- * rmt.h
- *
- * Added routines to replace open(), close(), lseek(), ioctl(), etc.
- * The preprocessor can be used to remap these the rmtopen(), etc
- * thus minimizing source changes.
- *
- * This file must be included before <sys/stat.h>, since it redefines
- * stat to be rmtstat, so that struct stat xyzzy; declarations work
- * properly.
- *
- * -- Fred Fish (w/some changes by Arnold Robbins)
- */
-
-
- #ifndef access /* avoid multiple redefinition */
- #ifndef lint /* in this case what lint doesn't know won't hurt it */
- #define access rmtaccess
- #define close rmtclose
- #define creat rmtcreat
- #define dup rmtdup
- #define fcntl rmtfcntl
- #define fstat rmtfstat
- #define ioctl rmtioctl
- #define isatty rmtisatty
- #define lseek rmtlseek
- #define lstat rmtlstat
- #define open rmtopen
- #define read rmtread
- #define stat rmtstat
- #define write rmtwrite
-
- extern long rmtlseek (); /* all the rest are int's */
- #endif
- #endif
- SHAR_EOF
- fi
- echo shar: "extracting 'rmtlib.c'" '(16015 characters)'
- if test -f 'rmtlib.c'
- then
- echo shar: "will not over-write existing file 'rmtlib.c'"
- else
- cat << \SHAR_EOF > 'rmtlib.c'
- #ifndef lint
- static char *RCSid = "$Header: /usr/src/local/usr.lib/librmt/RCS/rmtlib.c,v 1.7 89/03/23 14:09:51 root Exp Locker: root $";
- #endif
-
- /*
- * $Log: rmtlib.c,v $
- * Revision 1.7 89/03/23 14:09:51 root
- * Fix from haynes@ucscc.ucsc.edu for use w/compat. ADR.
- *
- * Revision 1.6 88/10/25 17:04:29 root
- * rexec code and a bug fix from srs!dan, miscellanious cleanup. ADR.
- *
- * Revision 1.5 88/10/25 16:30:17 root
- * Fix from jeff@gatech.edu for getting user@host:dev right. ADR.
- *
- * Revision 1.4 87/10/30 10:36:12 root
- * Made 4.2 syntax a compile time option. ADR.
- *
- * Revision 1.3 87/04/22 11:16:48 root
- * Two fixes from parmelee@wayback.cs.cornell.edu to correctly
- * do fd biasing and rmt protocol on 'S' command. ADR.
- *
- * Revision 1.2 86/10/09 16:38:53 root
- * Changed to reflect 4.3BSD rcp syntax. ADR.
- *
- * Revision 1.1 86/10/09 16:17:35 root
- * Initial revision
- *
- */
-
- /*
- * rmt --- remote tape emulator subroutines
- *
- * Originally written by Jeff Lee, modified some by Arnold Robbins
- *
- * WARNING: The man page rmt(8) for /etc/rmt documents the remote mag
- * tape protocol which rdump and rrestore use. Unfortunately, the man
- * page is *WRONG*. The author of the routines I'm including originally
- * wrote his code just based on the man page, and it didn't work, so he
- * went to the rdump source to figure out why. The only thing he had to
- * change was to check for the 'F' return code in addition to the 'E',
- * and to separate the various arguments with \n instead of a space. I
- * personally don't think that this is much of a problem, but I wanted to
- * point it out.
- * -- Arnold Robbins
- *
- * Redone as a library that can replace open, read, write, etc, by
- * Fred Fish, with some additional work by Arnold Robbins.
- */
-
- /*
- * MAXUNIT --- Maximum number of remote tape file units
- *
- * READ --- Return the number of the read side file descriptor
- * WRITE --- Return the number of the write side file descriptor
- */
-
- #define RMTIOCTL 1
- /* #define USE_REXEC 1 /* rexec code courtesy of Dan Kegel, srs!dan */
-
- #include <stdio.h>
- #include <signal.h>
- #include <sys/types.h>
-
- #ifdef RMTIOCTL
- #include <sys/ioctl.h>
- #include <sys/mtio.h>
- #endif
-
- #ifdef USE_REXEC
- #include <netdb.h>
- #endif
-
- #include <errno.h>
- #include <setjmp.h>
- #include <sys/stat.h>
-
- #define BUFMAGIC 64 /* a magic number for buffer sizes */
- #define MAXUNIT 4
-
- #define READ(fd) (Ctp[fd][0])
- #define WRITE(fd) (Ptc[fd][1])
-
- static int Ctp[MAXUNIT][2] = { -1, -1, -1, -1, -1, -1, -1, -1 };
- static int Ptc[MAXUNIT][2] = { -1, -1, -1, -1, -1, -1, -1, -1 };
-
- static jmp_buf Jmpbuf;
- extern int errno;
-
- /*
- * abort --- close off a remote tape connection
- */
-
- static void abort(fildes)
- int fildes;
- {
- close(READ(fildes));
- close(WRITE(fildes));
- READ(fildes) = -1;
- WRITE(fildes) = -1;
- }
-
-
-
- /*
- * command --- attempt to perform a remote tape command
- */
-
- static int command(fildes, buf)
- int fildes;
- char *buf;
- {
- register int blen;
- int (*pstat)();
-
- /*
- * save current pipe status and try to make the request
- */
-
- blen = strlen(buf);
- pstat = signal(SIGPIPE, SIG_IGN);
- if (write(WRITE(fildes), buf, blen) == blen)
- {
- signal(SIGPIPE, pstat);
- return(0);
- }
-
- /*
- * something went wrong. close down and go home
- */
-
- signal(SIGPIPE, pstat);
- abort(fildes);
-
- errno = EIO;
- return(-1);
- }
-
-
-
- /*
- * status --- retrieve the status from the pipe
- */
-
- static int status(fildes)
- int fildes;
- {
- int i;
- char c, *cp;
- char buffer[BUFMAGIC];
-
- /*
- * read the reply command line
- */
-
- for (i = 0, cp = buffer; i < BUFMAGIC; i++, cp++)
- {
- if (read(READ(fildes), cp, 1) != 1)
- {
- abort(fildes);
- errno = EIO;
- return(-1);
- }
- if (*cp == '\n')
- {
- *cp = 0;
- break;
- }
- }
-
- if (i == BUFMAGIC)
- {
- abort(fildes);
- errno = EIO;
- return(-1);
- }
-
- /*
- * check the return status
- */
-
- for (cp = buffer; *cp; cp++)
- if (*cp != ' ')
- break;
-
- if (*cp == 'E' || *cp == 'F')
- {
- errno = atoi(cp + 1);
- while (read(READ(fildes), &c, 1) == 1)
- if (c == '\n')
- break;
-
- if (*cp == 'F')
- abort(fildes);
-
- return(-1);
- }
-
- /*
- * check for mis-synced pipes
- */
-
- if (*cp != 'A')
- {
- abort(fildes);
- errno = EIO;
- return(-1);
- }
-
- return(atoi(cp + 1));
- }
-
- #ifdef USE_REXEC
-
- /*
- * _rmt_rexec
- *
- * execute /etc/rmt on a remote system using rexec().
- * Return file descriptor of bidirectional socket for stdin and stdout
- * If username is NULL, or an empty string, uses current username.
- *
- * ADR: By default, this code is not used, since it requires that
- * the user have a .netrc file in his/her home directory, or that the
- * application designer be willing to have rexec prompt for login and
- * password info. This may be unacceptable, and .rhosts files for use
- * with rsh are much more common on BSD systems.
- */
-
- static int
- _rmt_rexec(host, user)
- char *host;
- char *user; /* may be NULL */
- {
- struct servent *rexecserv;
-
- rexecserv = getservbyname("exec", "tcp");
- if (NULL == rexecserv) {
- fprintf (stderr, "? exec/tcp: service not available.");
- exit (-1);
- }
- if ((user != NULL) && *user == '\0')
- user = (char *) NULL;
- return rexec (&host, rexecserv->s_port, user, NULL,
- "/etc/rmt", (int *)NULL);
- }
- #endif /* USE_REXEC */
-
- /*
- * _rmt_open --- open a magtape device on system specified, as given user
- *
- * file name has the form [user@]system:/dev/????
- #ifdef COMPAT
- * file name has the form system[.user]:/dev/????
- #endif
- */
-
- #define MAXHOSTLEN 257 /* BSD allows very long host names... */
-
- static int _rmt_open (path, oflag, mode)
- char *path;
- int oflag;
- int mode;
- {
- int i, rc;
- char buffer[BUFMAGIC];
- char system[MAXHOSTLEN];
- char device[BUFMAGIC];
- char login[BUFMAGIC];
- char *sys, *dev, *user;
-
- sys = system;
- dev = device;
- user = login;
-
- /*
- * first, find an open pair of file descriptors
- */
-
- for (i = 0; i < MAXUNIT; i++)
- if (READ(i) == -1 && WRITE(i) == -1)
- break;
-
- if (i == MAXUNIT)
- {
- errno = EMFILE;
- return(-1);
- }
-
- /*
- * pull apart system and device, and optional user
- * don't munge original string
- * if COMPAT is defined, also handle old (4.2) style person.site notation.
- */
-
- while (*path != '@'
- #ifdef COMPAT
- && *path != '.'
- #endif
- && *path != ':') {
- *sys++ = *path++;
- }
- *sys = '\0';
- path++;
-
- if (*(path - 1) == '@')
- {
- (void) strcpy (user, system); /* saw user part of user@host */
- sys = system; /* start over */
- while (*path != ':') {
- *sys++ = *path++;
- }
- *sys = '\0';
- path++;
- }
- #ifdef COMPAT
- else if (*(path - 1) == '.')
- {
- while (*path != ':') {
- *user++ = *path++;
- }
- *user = '\0';
- path++;
- }
- #endif
- else
- *user = '\0';
-
- while (*path) {
- *dev++ = *path++;
- }
- *dev = '\0';
-
- #ifdef USE_REXEC
- /*
- * Execute the remote command using rexec
- */
- READ(i) = WRITE(i) = _rmt_rexec(system, login);
- if (READ(i) < 0)
- return -1;
- #else
- /*
- * setup the pipes for the 'rsh' command and fork
- */
-
- if (pipe(Ptc[i]) == -1 || pipe(Ctp[i]) == -1)
- return(-1);
-
- if ((rc = fork()) == -1)
- return(-1);
-
- if (rc == 0)
- {
- close(0);
- dup(Ptc[i][0]);
- close(Ptc[i][0]); close(Ptc[i][1]);
- close(1);
- dup(Ctp[i][1]);
- close(Ctp[i][0]); close(Ctp[i][1]);
- (void) setuid (getuid ());
- (void) setgid (getgid ());
- if (*login)
- {
- execl("/usr/ucb/rsh", "rsh", system, "-l", login,
- "/etc/rmt", (char *) 0);
- execl("/usr/bin/remsh", "remsh", system, "-l", login,
- "/etc/rmt", (char *) 0);
- }
- else
- {
- execl("/usr/ucb/rsh", "rsh", system,
- "/etc/rmt", (char *) 0);
- execl("/usr/bin/remsh", "remsh", system,
- "/etc/rmt", (char *) 0);
- }
-
- /*
- * bad problems if we get here
- */
-
- perror("exec");
- exit(1);
- }
-
- close(Ptc[i][0]); close(Ctp[i][1]);
- #endif
-
- /*
- * now attempt to open the tape device
- */
-
- sprintf(buffer, "O%s\n%d\n", device, oflag);
- if (command(i, buffer) == -1 || status(i) == -1)
- return(-1);
-
- return(i);
- }
-
-
-
- /*
- * _rmt_close --- close a remote magtape unit and shut down
- */
-
- static int _rmt_close(fildes)
- int fildes;
- {
- int rc;
-
- if (command(fildes, "C\n") != -1)
- {
- rc = status(fildes);
-
- abort(fildes);
- return(rc);
- }
-
- return(-1);
- }
-
-
-
- /*
- * _rmt_read --- read a buffer from a remote tape
- */
-
- static int _rmt_read(fildes, buf, nbyte)
- int fildes;
- char *buf;
- unsigned int nbyte;
- {
- int rc, i;
- char buffer[BUFMAGIC];
-
- 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)
- {
- abort(fildes);
- errno = EIO;
- return(-1);
- }
- }
-
- return(rc);
- }
-
-
-
- /*
- * _rmt_write --- write a buffer to the remote tape
- */
-
- static int _rmt_write(fildes, buf, nbyte)
- int fildes;
- char *buf;
- unsigned int nbyte;
- {
- int rc;
- char buffer[BUFMAGIC];
- int (*pstat)();
-
- sprintf(buffer, "W%d\n", nbyte);
- if (command(fildes, buffer) == -1)
- return(-1);
-
- pstat = signal(SIGPIPE, SIG_IGN);
- if (write(WRITE(fildes), buf, nbyte) == nbyte)
- {
- signal (SIGPIPE, pstat);
- return(status(fildes));
- }
-
- signal (SIGPIPE, pstat);
- abort(fildes);
- errno = EIO;
- return(-1);
- }
-
-
-
- /*
- * _rmt_lseek --- perform an imitation lseek operation remotely
- */
-
- static long _rmt_lseek(fildes, offset, whence)
- int fildes;
- long offset;
- int whence;
- {
- char buffer[BUFMAGIC];
-
- sprintf(buffer, "L%d\n%d\n", offset, whence);
- if (command(fildes, buffer) == -1)
- return(-1);
-
- return(status(fildes));
- }
-
-
- /*
- * _rmt_ioctl --- perform raw tape operations remotely
- */
-
- #ifdef RMTIOCTL
- static _rmt_ioctl(fildes, op, arg)
- int fildes, op;
- char *arg;
- {
- char c;
- int rc, cnt;
- char buffer[BUFMAGIC];
-
- /*
- * MTIOCOP is the easy one. nothing is transfered in binary
- */
-
- if (op == MTIOCTOP)
- {
- 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));
- }
-
- /*
- * we can only handle 2 ops, if not the other one, punt
- */
-
- if (op != MTIOCGET)
- {
- errno = EINVAL;
- return(-1);
- }
-
- /*
- * grab the status and read it directly into the structure
- * this assumes that the status buffer is (hopefully) not
- * padded and that 2 shorts fit in a long without any word
- * alignment problems, ie - 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)
- {
- abort(fildes);
- errno = EIO;
- return(-1);
- }
- }
-
- /*
- * now we 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 /* RMTIOCTL */
-
- /*
- * Added routines to replace open(), close(), lseek(), ioctl(), etc.
- * The preprocessor can be used to remap these the rmtopen(), etc
- * thus minimizing source changes:
- *
- * #ifdef <something>
- * # define access rmtaccess
- * # define close rmtclose
- * # define creat rmtcreat
- * # define dup rmtdup
- * # define fcntl rmtfcntl
- * # define fstat rmtfstat
- * # define ioctl rmtioctl
- * # define isatty rmtisatty
- * # define lseek rmtlseek
- * # define lstat rmtlstat
- * # define open rmtopen
- * # define read rmtread
- * # define stat rmtstat
- * # define write rmtwrite
- * #endif
- *
- * -- Fred Fish
- *
- * ADR --- I set up a <rmt.h> include file for this
- *
- */
-
- /*
- * Note that local vs remote file descriptors are distinquished
- * by adding a bias to the remote descriptors. This is a quick
- * and dirty trick that may not be portable to some systems.
- */
-
- #define REM_BIAS 128
-
-
- /*
- * Test pathname to see if it is local or remote. A remote device
- * is any string that contains ":/dev/". Returns 1 if remote,
- * 0 otherwise.
- */
-
- static int remdev (path)
- register char *path;
- {
- #define strchr index
- extern char *strchr ();
-
- if ((path = strchr (path, ':')) != NULL)
- {
- if (strncmp (path + 1, "/dev/", 5) == 0)
- {
- return (1);
- }
- }
- return (0);
- }
-
-
- /*
- * Open a local or remote file. Looks just like open(2) to
- * caller.
- */
-
- int rmtopen (path, oflag, mode)
- char *path;
- int oflag;
- int mode;
- {
- int fd;
-
- if (remdev (path))
- {
- fd = _rmt_open (path, oflag, mode);
-
- return (fd == -1) ? -1 : (fd + REM_BIAS);
- }
- else
- {
- return (open (path, oflag, mode));
- }
- }
-
- /*
- * Test pathname for specified access. Looks just like access(2)
- * to caller.
- */
-
- int rmtaccess (path, amode)
- char *path;
- int amode;
- {
- if (remdev (path))
- {
- return (0); /* Let /etc/rmt find out */
- }
- else
- {
- return (access (path, amode));
- }
- }
-
-
- /*
- * Read from stream. Looks just like read(2) to caller.
- */
-
- int rmtread (fildes, buf, nbyte)
- int fildes;
- char *buf;
- unsigned int nbyte;
- {
- if (isrmt (fildes))
- {
- return (_rmt_read (fildes - REM_BIAS, buf, nbyte));
- }
- else
- {
- return (read (fildes, buf, nbyte));
- }
- }
-
-
- /*
- * Write to stream. Looks just like write(2) to caller.
- */
-
- int rmtwrite (fildes, buf, nbyte)
- int fildes;
- char *buf;
- unsigned int nbyte;
- {
- if (isrmt (fildes))
- {
- return (_rmt_write (fildes - REM_BIAS, buf, nbyte));
- }
- else
- {
- return (write (fildes, buf, nbyte));
- }
- }
-
- /*
- * Perform lseek on file. Looks just like lseek(2) to caller.
- */
-
- long rmtlseek (fildes, offset, whence)
- int fildes;
- long offset;
- int whence;
- {
- if (isrmt (fildes))
- {
- return (_rmt_lseek (fildes - REM_BIAS, offset, whence));
- }
- else
- {
- return (lseek (fildes, offset, whence));
- }
- }
-
-
- /*
- * Close a file. Looks just like close(2) to caller.
- */
-
- int rmtclose (fildes)
- int fildes;
- {
- if (isrmt (fildes))
- {
- return (_rmt_close (fildes - REM_BIAS));
- }
- else
- {
- return (close (fildes));
- }
- }
-
- /*
- * Do ioctl on file. Looks just like ioctl(2) to caller.
- */
-
- int rmtioctl (fildes, request, arg)
- int fildes;
- unsigned long request;
- char *arg;
- {
- if (isrmt (fildes))
- {
- #ifdef RMTIOCTL
- return (_rmt_ioctl (fildes - REM_BIAS, request, arg));
- #else
- errno = EOPNOTSUPP;
- return (-1); /* For now (fnf) */
- #endif
- }
- else
- {
- return (ioctl (fildes, request, arg));
- }
- }
-
-
- /*
- * Duplicate an open file descriptor. Looks just like dup(2)
- * to caller.
- */
-
- int rmtdup (fildes)
- int fildes;
- {
- if (isrmt (fildes))
- {
- errno = EOPNOTSUPP;
- return (-1); /* For now (fnf) */
- }
- else
- {
- return (dup (fildes));
- }
- }
-
- /*
- * Get file status. Looks just like fstat(2) to caller.
- */
-
- int rmtfstat (fildes, buf)
- int fildes;
- struct stat *buf;
- {
- if (isrmt (fildes))
- {
- errno = EOPNOTSUPP;
- return (-1); /* For now (fnf) */
- }
- else
- {
- return (fstat (fildes, buf));
- }
- }
-
-
- /*
- * Get file status. Looks just like stat(2) to caller.
- */
-
- int rmtstat (path, buf)
- char *path;
- struct stat *buf;
- {
- if (remdev (path))
- {
- errno = EOPNOTSUPP;
- return (-1); /* For now (fnf) */
- }
- else
- {
- return (stat (path, buf));
- }
- }
-
-
-
- /*
- * Create a file from scratch. Looks just like creat(2) to the caller.
- */
-
- #include <sys/file.h> /* BSD DEPENDANT!!! */
- /* #include <fcntl.h> /* use this one for S5 with remote stuff */
-
- int rmtcreat (path, mode)
- char *path;
- int mode;
- {
- if (remdev (path))
- {
- return (rmtopen (path, 1 | O_CREAT, mode));
- }
- else
- {
- return (creat (path, mode));
- }
- }
-
- /*
- * Isrmt. Let a programmer know he has a remote device.
- */
-
- int isrmt (fd)
- int fd;
- {
- return (fd >= REM_BIAS);
- }
-
- /*
- * Rmtfcntl. Do a remote fcntl operation.
- */
-
- int rmtfcntl (fd, cmd, arg)
- int fd, cmd, arg;
- {
- if (isrmt (fd))
- {
- errno = EOPNOTSUPP;
- return (-1);
- }
- else
- {
- return (fcntl (fd, cmd, arg));
- }
- }
-
- /*
- * Rmtisatty. Do the isatty function.
- */
-
- int rmtisatty (fd)
- int fd;
- {
- if (isrmt (fd))
- return (0);
- else
- return (isatty (fd));
- }
-
-
- /*
- * Get file status, even if symlink. Looks just like lstat(2) to caller.
- */
-
- int rmtlstat (path, buf)
- char *path;
- struct stat *buf;
- {
- if (remdev (path))
- {
- errno = EOPNOTSUPP;
- return (-1); /* For now (fnf) */
- }
- else
- {
- return (lstat (path, buf));
- }
- }
- SHAR_EOF
- fi
- echo shar: "extracting 'rmtops.3'" '(5300 characters)'
- if test -f 'rmtops.3'
- then
- echo shar: "will not over-write existing file 'rmtops.3'"
- else
- cat << \SHAR_EOF > 'rmtops.3'
- ...
- ... $Header: rmtops.3,v 1.4 88/10/25 17:05:05 root Locked $
- ...
- ... $Log: rmtops.3,v $
- ... Revision 1.4 88/10/25 17:05:05 root
- ... Documented configuration options and added Dan Kegel to AUTHORS. ADR.
- ...
- ... Revision 1.3 87/10/30 10:36:38 root
- ... Some cleanup. 4.3 syntax is default, 4.2 is a compile time option.
- ...
- ... Revision 1.2 86/10/09 16:38:02 root
- ... Changed to reflect 4.3BSD rcp syntax and better rmt(8) capabilities. ADR.
- ...
- ... Revision 1.1 86/10/09 16:18:47 root
- ... Initial revision
- ...
- ...
- .TH RMTOPS 3 local
- .SH NAME
- rmtops \- access tape drives on remote machines
- .SH SYNOPSIS
- .nf
- .ft B
- #include <rmt.h>
- #include <sys/stat.h> /* MUST come after <rmt.h> */
-
- int isrmt (fd)
- int fd;
-
- int rmtaccess (file, mode)
- char *file;
- int mode;
-
- int rmtclose (fd)
- int fd;
-
- int rmtcreat (file, mode)
- char *file;
- int mode;
-
- int rmtdup (fd)
- int fd;
-
- int rmtfcntl (fd, cmd, arg)
- int fd, cmd, arg;
-
- int rmtfstat (fd, buf)
- int fd;
- struct stat *buf;
-
- int rmtioctl (fd, request, argp)
- int fd, request;
- char *argp;
-
- int rmtisatty (fd)
- int fd;
-
- long rmtlseek (fd, offset, whence)
- int fd, whence;
- long offset;
-
- int rmtlstat (file, buf)
- char *file;
- struct stat *buf;
-
- int rmtopen (file, flags [, mode])
- char *file;
- int flags, mode;
-
- int rmtread (fd, buf, nbytes)
- int fd, nbytes;
- char *buf;
-
- int rmtstat (file, buf)
- char *file;
- struct stat *buf;
-
- int rmtwrite (fd, buf, nbytes)
- int fd, nbytes;
- char *buf;
- .fi
- .ft R
- .SH DESCRIPTION
- .I Rmtops
- provides a simple means of transparently accessing tape drives
- on remote machines over the ethernet, via
- .IR rsh (1)
- and
- .IR rmt (8).
- These routines are used like their corresponding
- system calls, but allow the user to open up a tape drive on a remote
- system on which he or she has an account and the appropriate remote
- permissions.
- .PP
- A remote tape drive file name has the form
- .sp
- .RS
- .RI [ user @] system :/dev/???
- .RE
- .sp
- where
- .I system
- is the remote system,
- .I /dev/???
- is the particular drive on the remote system (raw, blocked, rewinding,
- non-rewinding, etc.), and the optional
- .I user
- is the login name to be used on the remote system, if different from
- the current user's login name.
- .PP
- The library source code may be optionally compiled to recognize the
- old, 4.2 BSD, remote syntax
- .sp
- .RS
- .IR system [. user ]:/dev/???
- .RE
- .sp
- By default, only the first form (introduced in 4.3 BSD) is recognized.
- .PP
- For transparency, the user should include the file
- .IR <rmt.h> ,
- which has the following defines in it:
- .PP
- .nf
- #define access rmtaccess
- #define close rmtclose
- #define creat rmtcreat
- #define dup rmtdup
- #define fcntl rmtfcntl
- #define fstat rmtfstat
- #define ioctl rmtioctl
- #define isatty rmtisatty
- #define lseek rmtlseek
- #define lstat rmtlstat
- #define open rmtopen
- #define read rmtread
- #define stat rmtstat
- #define write rmtwrite
- .fi
- .PP
- This allows the programmer to use
- .IR open ,
- .IR close ,
- .IR read ,
- .IR write ,
- etc. in their normal fashion, with the
- .I rmtops
- routines taking care of differentiating between local and remote files.
- This file should be included
- .I before
- including the file
- .IR <sys/stat.h> ,
- since it redefines the identifier ``stat,'' which is used to declare
- objects of type
- .BR "struct stat" .
- .PP
- The routines differentiate between local and remote file descriptors by
- adding a bias (currently 128) to the file descriptor of the pipe.
- The programmer, if he or she must know if a file is remote, should use the
- .I isrmt
- function.
- .SH FILES
- .TP
- .B /usr/lib/librmt.a
- Contains the remote tape library. To include the library with a program,
- add the flag
- .B \-lrmt
- to the
- .IR cc (1)
- command line.
- .SH SEE ALSO
- .IR rcp (1),
- .IR rsh (1),
- .IR rmt (8),
- and the appropriate system calls in section 2.
- .SH DIAGNOSTICS
- Several of these routines will return \-1 and set
- .I errno
- to EOPNOTSUPP, if they are given a remote file name or a file descriptor
- on an open remote file (e.g.,
- .IR rmtdup ).
- .SH BUGS
- See \s-1DIAGNOSTICS\s+1 above. It is to be hoped that true remote file systems
- will eventually appear, and eliminate the need for these routines.
- .PP
- There is no way to use remote tape drives with the
- .IR stdio (3)
- package, short of recompiling it entirely to use these routines.
- .PP
- The
- .IR rmt (8)
- protocol is not very capable. In particular, it relies on
- TCP/IP sockets for error free transmission, and does no data validation
- of its own.
- .SH CONFIGURATION OPTIONS
- The library may be compiled to allow the use of 4.2 BSD style remote
- file names. This is not recommended.
- .PP
- By default, the library opens two pipes to
- .IR rsh (1).
- It may optionally be compiled to use
- .IR rexec (3),
- instead. Doing so requires the use of a
- .I .netrc
- file in the user's home directory, or that the application designer
- be willing to have
- .I rexec
- prompt the user for a login name and password on the remote host.
- .SH AUTHORS
- Jeff Lee (gatech!jeff) wrote the original routines for accessing
- tape drives via
- .IR rmt (8).
- .PP
- Fred Fish (unisoft!fnf) redid them into a general purpose library.
- .PP
- Arnold Robbins
- (formerly gatech!arnold, now emory!arnold)
- added the ability to specify a user
- name on the remote system, the
- .B <rmt.h>
- include file, this man page,
- cleaned up the library a little,
- and made the appropriate changes for 4.3 BSD.
- .PP
- Dan Kegel (srs!dan) contributed the code to use
- .IR rexec (3)
- library routine.
- SHAR_EOF
- fi
- exit 0
- # End of shell archive
-
-