From 3f166ce0f5ac7c935eea8f826081e7dd4e90407b Mon Sep 17 00:00:00 2001 From: Sergey Poznyakoff Date: Tue, 6 Dec 2005 23:13:19 +0000 Subject: [PATCH] Update --info-scripts documentation --- doc/tar.texi | 66 ++++++++++++++++++++++++++-------------------------- 1 file changed, 33 insertions(+), 33 deletions(-) diff --git a/doc/tar.texi b/doc/tar.texi index 605c0ef..8d09671 100644 --- a/doc/tar.texi +++ b/doc/tar.texi @@ -2826,6 +2826,12 @@ from the archive. @xref{Recursive Unlink}. Directs @command{tar} to remove the source file from the file system after appending it to an archive. @xref{remove files}. +@item --restrict + +Disable use of some potentially harmful @command{tar} options. +Currently this option disables shell invocaton from multi-volume menu +(@pxref{Using Multiple Tapes}). + @item --rmt-command=@var{cmd} Notifies @command{tar} that it should use @var{cmd} instead of @@ -8619,9 +8625,8 @@ the first archive, using @value{op-multi-volume}, and then put in the second tape when prompted, so @command{tar} can restore both halves of the file.) -@GNUTAR{} multi-volume archives do not use a truly -portable format. You need @GNUTAR{} at both end to -process them properly. +@GNUTAR{} multi-volume archives do not use a truly portable format. +You need @GNUTAR{} at both ends to process them properly. When prompting for a new tape, @command{tar} accepts any of the following responses: @@ -8634,7 +8639,8 @@ Request @command{tar} to exit immediately. @item n @var{file name} Request @command{tar} to write the next volume on the file @var{file name}. @item ! -Request @command{tar} to run a subshell. +Request @command{tar} to run a subshell. This option can be disabled +by giving @option{--restrict} command line option to @command{tar}. @item y Request @command{tar} to begin writing the next volume. @end table @@ -8676,9 +8682,12 @@ Format of the archive being processed. @xref{Formats}, for a complete list of archive format names. @end table -If the program fails, @command{tar} exits; otherwise, it begins -writing the next volume. The behavior of the @samp{n} response to the -normal tape-change prompt is not available if you use @value{op-info-script}. +The info script can instruct @command{tar} to use new archive name, +by writing in to file descriptor 3 (see below for an +example). + +If the info script fails, @command{tar} exits; otherwise, it begins +writing the next volume. The method @command{tar} uses to detect end of tape is not perfect, and fails on some operating systems or on some devices. You can use the @@ -8701,43 +8710,34 @@ finished, it will rewrite the file with the now-current volume number. per @value{ref-label}, it @emph{only} affects the number used in the prompt.) -If you want @command{tar} to cycle through a series of tape drives, then -you can use the @samp{n} response to the tape-change prompt. This -method can be used with info scripts as well, although it is not as -straight-forward as using @samp{n} response. For example, the -following script cycles through a series of archive files named -@file{archive-@var{vol}}, where @var{vol} is the archive volume -number: +If you want @command{tar} to cycle through a series of files or tape +drives, there are three approaches to choose from. First of all, you +can give @command{tar} multiple @value{op-file} options. In this case +the specified files will be used, in sequence, as the successive +volumes of the archive. Only when the first one in the sequence needs +to be used again will @command{tar} prompt for a tape change (or run +the info script). Secondly, you can use the @samp{n} response to the +tape-change prompt, and, finally, you can use an info script, that +writes new archive name to file descriptor. The following example +illustrates this approach: @smallexample @group +#! /bin/sh echo Preparing volume $TAR_VOLUME of $TAR_ARCHIVE. +name=`expr $TAR_ARCHIVE : '\(.*\)-.*'` case $TAR_SUBCOMMAND in --c) mv $TAR_ARCHIVE $@{TAR_ARCHIVE@}$(($TAR_VOLUME - 1));; --d|-x|-t) test -r $@{TAR_ARCHIVE@}$(($TAR_VOLUME)) || exit 1 - ln -sf $@{TAR_ARCHIVE@}$(($TAR_VOLUME)) $TAR_ARCHIVE;; +-c) ;; +-d|-x|-t) test -r $@{name:-$TAR_ARCHIVE@}-$TAR_VOLUME || exit 1 + ;; *) exit 1 esac + +echo $@{name:-$TAR_ARCHIVE@}-$TAR_VOLUME >&3 @end group @end smallexample -@noindent -The same approach can be used to cycle through a series of tape drives. - -Another possibility is to give @command{tar} multiple @value{op-file} -options. In this case the specified files will be used, in sequence, -as the successive volumes of the archive. Only when the first one in -the sequence needs to be used again will @command{tar} prompt for a -tape change (or run the info script). - -Multi-volume archives - -With @value{op-multi-volume}, @command{tar} will not abort when it cannot -read or write any more data. Instead, it will ask you to prepare a new -volume. If the archive is on a magnetic tape, you should change tapes -now; if the archive is on a floppy disk, you should change disks, etc. - Each volume of a multi-volume archive is an independent @command{tar} archive, complete in itself. For example, you can list or extract any volume alone; just don't specify @value{op-multi-volume}. However, if one -- 2.45.2