Add -P arguments for dump(8) and restore(8) which allow the user to

use backup methods other than files and tapes.  The -P argument is
a normal sh(1) pipeline with either $DUMP_VOLUME or $RESTORE_VOLUME
defined in the environment, respectively.

For example, I can back up my home to three DVD+R[W]s as so:
Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
/dev/ad0s2e  40028550 10093140 26733126    27%    /home
green# dump -0 -L -C16 -B4589840 -P 'growisofs -Z /dev/cd0=/dev/fd/0' /home

4 files changed, 92 insertions, 19 deletions

diff --git a/sbin/restore/extern.h b/sbin/restore/extern.h
index 2d1f464..9edf6f9 100644
--- a/sbin/restore/extern.h
+++ b/sbin/restore/extern.h
@@ -87,7 +87,7 @@ void		 rst_closedir(RST_DIR *dirp);
 void	 	 runcmdshell(void);
 char		*savename(char *);
 void	 	 setdirmodes(int);
-void		 setinput(char *);
+void		 setinput(char *, int);
 void		 setup(void);
 void	 	 skipdirs(void);
 void		 skipfile(void);
diff --git a/sbin/restore/main.c b/sbin/restore/main.c
index 9006ea5..b2ace5d 100644
--- a/sbin/restore/main.c
+++ b/sbin/restore/main.c
@@ -62,6 +62,7 @@ static const char rcsid[] =
 int	bflag = 0, cvtflag = 0, dflag = 0, vflag = 0, yflag = 0;
 int	hflag = 1, mflag = 1, Nflag = 0;
 int	uflag = 0;
+int	pipecmd = 0;
 char	command = '\0';
 long	dumpnum = 1;
 long	volno = 0;
@@ -93,10 +94,9 @@ main(int argc, char *argv[])
 
 	(void)setlocale(LC_ALL, "");
 
-	if ((inputdev = getenv("TAPE")) == NULL)
-		inputdev = _PATH_DEFTAPE;
+	inputdev = NULL;
 	obsolete(&argc, &argv);
-	while ((ch = getopt(argc, argv, "b:df:himNRrs:tuvxy")) != -1)
+	while ((ch = getopt(argc, argv, "b:df:himNP:Rrs:tuvxy")) != -1)
 		switch(ch) {
 		case 'b':
 			/* Change default tape blocksize. */
@@ -111,8 +111,18 @@ main(int argc, char *argv[])
 			dflag = 1;
 			break;
 		case 'f':
+			if (pipecmd)
+				errx(1,
+				    "-P and -f options are mutually exclusive");
 			inputdev = optarg;
 			break;
+		case 'P':
+			if (!pipecmd && inputdev)
+				errx(1,
+				    "-P and -f options are mutually exclusive");
+			inputdev = optarg;
+			pipecmd = 1;
+			break;
 		case 'h':
 			hflag = 0;
 			break;
@@ -165,7 +175,9 @@ main(int argc, char *argv[])
 		(void) signal(SIGTERM, SIG_IGN);
 	setlinebuf(stderr);
 
-	setinput(inputdev);
+	if (inputdev == NULL && (inputdev = getenv("TAPE")) == NULL)
+		inputdev = _PATH_DEFTAPE;
+	setinput(inputdev, pipecmd);
 
 	if (argc == 0) {
 		argc = 1;
@@ -277,12 +289,17 @@ main(int argc, char *argv[])
 static void
 usage()
 {
-	(void)fprintf(stderr, "usage:\t%s\n\t%s\n\t%s\n\t%s\n\t%s\n",
-	  "restore -i [-cdhmNuvy] [-b blocksize] [-f file] [-s fileno]",
-	  "restore -r [-cdNuvy] [-b blocksize] [-f file] [-s fileno]",
-	  "restore -R [-cdNuvy] [-b blocksize] [-f file] [-s fileno]",
-	  "restore -x [-cdhmNuvy] [-b blocksize] [-f file] [-s fileno] [file ...]",
-	  "restore -t [-cdhNuvy] [-b blocksize] [-f file] [-s fileno] [file ...]");
+	const char *const common =
+	    "[-b blocksize] [-P pipecmd | -f file] [-s fileno]";
+	const char *const fileell = "[file ...]";
+
+	(void)fprintf(stderr, "usage:\t%s %s\n\t%s %s\n\t%s %s\n"
+	    "\t%s %s %s\n\t%s %s %s\n",
+	    "restore -i [-cdhmNuvy]", common,
+	    "restore -r [-cdNuvy]", common,
+	    "restore -R [-cdNuvy]", common,
+	    "restore -x [-cdhmNuvy]", common, fileell,
+	    "restore -t [-cdhNuvy]", common, fileell);
 	done(1);
 }
 
diff --git a/sbin/restore/restore.8 b/sbin/restore/restore.8
index 4d970a7..8b1514a 100644
--- a/sbin/restore/restore.8
+++ b/sbin/restore/restore.8
@@ -40,32 +40,32 @@
 .Fl i
 .Op Fl cdhmNuvy
 .Op Fl b Ar blocksize
-.Op Fl f Ar file
+.Op Fl f Ar file | Fl P Ar pipecommand
 .Op Fl s Ar fileno
 .Nm
 .Fl R
 .Op Fl cdNuvy
 .Op Fl b Ar blocksize
-.Op Fl f Ar file
+.Op Fl f Ar file | Fl P Ar pipecommand
 .Op Fl s Ar fileno
 .Nm
 .Fl r
 .Op Fl cdNuvy
 .Op Fl b Ar blocksize
-.Op Fl f Ar file
+.Op Fl f Ar file | Fl P Ar pipecommand
 .Op Fl s Ar fileno
 .Nm
 .Fl t
 .Op Fl cdhNuvy
 .Op Fl b Ar blocksize
-.Op Fl f Ar file
+.Op Fl f Ar file | Fl P Ar pipecommand
 .Op Fl s Ar fileno
 .Op Ar
 .Nm
 .Fl x
 .Op Fl cdhmNuvy
 .Op Fl b Ar blocksize
-.Op Fl f Ar file
+.Op Fl f Ar file | Fl P Ar pipecommand
 .Op Fl s Ar fileno
 .Op Ar
 .Pp
@@ -93,7 +93,9 @@ The
 utility works across a network;
 to do this see the
 .Fl f
-flag described below.
+and
+.Fl P
+flags described below.
 Other arguments to the command are file or directory
 names specifying the files that are to be restored.
 Unless the
@@ -304,6 +306,25 @@ or
 .Nm
 reads from the named file on the remote host using
 .Xr rmt 8 .
+.It Fl P Ar pipecommand
+Use
+.Xr popen 3
+to execute the
+.Xr sh 1
+script string defined by
+.Ar pipecommand
+as the input for every volume in the backup.
+This child pipeline's
+.Dv stdout
+.Pa ( /dev/fd/1 )
+is redirected to the
+.Nm
+input stream, and the environment variable
+.Ev RESTORE_VOLUME
+is set to the current volume number being read.
+The
+.Ar pipecommand
+script is started each time a volume is loaded, as if it were a tape drive.
 .It Fl h
 Extract the actual directory,
 rather than the files that it references.
diff --git a/sbin/restore/tape.c b/sbin/restore/tape.c
index 0b59364..6a2163b 100644
--- a/sbin/restore/tape.c
+++ b/sbin/restore/tape.c
@@ -65,6 +65,8 @@ static const char rcsid[] =
 static long	fssize = MAXBSIZE;
 static int	mt = -1;
 static int	pipein = 0;
+static int	pipecmdin = 0;
+static FILE	*popenfp = NULL;
 static char	*magtape;
 static int	blkcnt;
 static int	numtrec;
@@ -109,7 +111,7 @@ static void	 xtrskip(char *, long);
  * Set up an input source
  */
 void
-setinput(char *source)
+setinput(char *source, int ispipecommand)
 {
 	FLUSHTAPEBUF();
 	if (bflag)
@@ -118,6 +120,9 @@ setinput(char *source)
 		newtapebuf(NTREC > HIGHDENSITYTREC ? NTREC : HIGHDENSITYTREC);
 	terminal = stdin;
 
+	if (ispipecommand)
+		pipecmdin++;
+	else
 #ifdef RRESTORE
 	if (strchr(source, ':')) {
 		host = source;
@@ -182,6 +187,15 @@ setup(void)
 	struct stat stbuf;
 
 	vprintf(stdout, "Verify tape and initialize maps\n");
+	if (pipecmdin) {
+		if (setenv("RESTORE_VOLUME", "1", 1) == -1) {
+			fprintf(stderr, "Cannot set $RESTORE_VOLUME: %s\n",
+			    strerror(errno));
+			done(1);
+		}
+		popenfp = popen(magtape, "r");
+		mt = popenfp ? fileno(popenfp) : -1;
+	} else
 #ifdef RRESTORE
 	if (host)
 		mt = rmtopen(magtape, 0);
@@ -304,6 +318,10 @@ getvol(long nextvol)
 		}
 		if (volno == 1)
 			return;
+		if (pipecmdin) {
+			closemt();
+			goto getpipecmdhdr;
+		}
 		goto gethdr;
 	}
 again:
@@ -364,6 +382,19 @@ again:
 		(void) strcpy(magtape, buf);
 		magtape[strlen(magtape) - 1] = '\0';
 	}
+	if (pipecmdin) {
+		char volno[sizeof("2147483647")];
+
+getpipecmdhdr:
+		(void)sprintf(volno, "%d", newvol);
+		if (setenv("RESTORE_VOLUME", volno, 1) == -1) {
+			fprintf(stderr, "Cannot set $RESTORE_VOLUME: %s\n",
+			    strerror(errno));
+			done(1);
+		}
+		popenfp = popen(magtape, "r");
+		mt = popenfp ? fileno(popenfp) : -1;
+	} else
 #ifdef RRESTORE
 	if (host)
 		mt = rmtopen(magtape, 0);
@@ -493,7 +524,7 @@ setdumpnum(void)
 		rmtioctl(MTFSF, dumpnum - 1);
 	else
 #endif
-		if (ioctl(mt, MTIOCTOP, (char *)&tcom) < 0)
+		if (!pipecmdin && ioctl(mt, MTIOCTOP, (char *)&tcom) < 0)
 			fprintf(stderr, "ioctl MTFSF: %s\n", strerror(errno));
 }
 
@@ -982,6 +1013,10 @@ closemt(void)
 
 	if (mt < 0)
 		return;
+	if (pipecmdin) {
+		pclose(popenfp);
+		popenfp = NULL;
+	} else
 #ifdef RRESTORE
 	if (host)
 		rmtclose();