From 8ccb487c21368a7fdc8c7c72315325bf0aa06147 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 19:44:12 +0200 Subject: Adding upstream version 3:4.8.29. Signed-off-by: Daniel Baumann --- src/vfs/extfs/helpers/README | 200 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 src/vfs/extfs/helpers/README (limited to 'src/vfs/extfs/helpers/README') diff --git a/src/vfs/extfs/helpers/README b/src/vfs/extfs/helpers/README new file mode 100644 index 0000000..5eb2a10 --- /dev/null +++ b/src/vfs/extfs/helpers/README @@ -0,0 +1,200 @@ + Writing scripts for Midnight Commander's external vfs + +IMPORTANT NOTE: There may be some bugs left in extfs. Enjoy. + +Starting with version 3.1, the Midnight Commander comes with so called +extfs, which is one of the virtual filesystems. This system makes it +possible to create new virtual filesystems for the GNU MC very easily. + +To handle requests, create a shell/perl/python/etc script/program +(with executable permissions) in $(libexecdir)/mc/extfs.d +or in ~/.local/share/mc/extfs.d/. + +(Note: $(libexecdir) should be substituted for actual libexecdir path +stored when configured or compiled, like /usr/local/libexec or /usr/libexec). + +Assign a vfs suffix. For example, if you have .zip file, and would like +to see what's inside it, path will be + +/anypath/my.zip/uzip://some_path/... + +In this example, .zip is suffix, but I call vfs 'uzip'. Why? Well, +what this vfs essentially does is UNzip. UN is too long, so I choosed +U. Note that sometime in future filesystem like zip may exist: It will +take whole tree and create .zip file from it. So /usr/zip:// will be +zipfile containing whole /usr tree. + +If your vfs does not require file to work on, add '+' to the end of name. +Note, that trailing '+' in file name is not a part of vfs name, it is +just an vfs attribue. So you have not use it in vfs commands: + +cd rpms:// + +is correct command, and + +cd rpms+:// + +is incorrect command. + + +* Commands that should be implemented by your shell script +---------------------------------------------------------- + +Return zero from your script upon completion of the command, otherwise +nonzero for failure or in case of an unsupported command. + +$libdir/extfs/prefix command [arguments] + +* Command: list archivename + +This command should list the complete archive content in the following format +(a little modified ls -l listing): + +AAAAAAA NNN OOOOOOOO GGGGGGGG SSSSSSSS DATETIME [PATH/]FILENAME [-> [PATH/]FILENAME[/]]] + +where (things in [] are optional): + +AAAAAAA is the permission string like in ls -l +NNN is the number of links +OOOOOOOO is the owner (either UID or name) +GGGGGGGG is the group (either GID or name) +SSSSSSSS is the file size +FILENAME is the filename +PATH is the path from the archive's root without the leading slash (/) +DATETIME has one of the following formats: + Mon DD hh:mm[:ss], Mon DD YYYY, MM-DD-YYYY hh:mm[:ss] + + where Mon is a three letter English month name, DD is day + 01-31 (can be 1-31, if following Mon), MM is month 01-12, + YYYY is four digit year, hh is hours, mm is minutes, + and ss is optional seconds. + +If the -> [PATH/]FILENAME part is present, it means: + +If permissions start with an l (ell), then it is the name that symlink +points to. (If this PATH starts with a MC vfs prefix, then it is a symlink +somewhere to the other virtual filesystem (if you want to specify path from +the local root, use local:/path_name instead of /path_name, since /path_name +means from root of the archive listed). + +If permissions do not start with l, but number of links is greater than one, +then it says that this file should be a hardlinked with the other file. + +The result of list command must not contain "." and ".." items. + +* Command: copyout archivename storedfilename extractto + +This should extract from archive archivename the file called +storedfilename (possibly with path if not located in archive's root +[this is wrong. current extfs strips paths! -- pavel@ucw.cz]) +to file extractto. + +* Command: copyin archivename storedfilename sourcefile + +This should add to the archivename the sourcefile with the name +storedfilename inside the archive. + +Important note: archivename in the above examples may not have the +extension you are expecting to have, like it may happen that +archivename will be something like /tmp/f43513254 or just +anything. Some archivers do not like it, so you'll have to find some +workaround. + +* Command: rm archivename storedfilename + +This should remove storedfilename from archivename. + +* Command: mkdir archivename dirname + +This should create a new directory called dirname inside archivename. + +* Command: rmdir archivename dirname + +This should remove an existing directory dirname. If the directory is +not empty, mc will recursively delete it (possibly prompting). + +* Command: run + +Undocumented :-) + +--------------------------------------------------------- + +Don't forget to mark this file executable (chmod 755 ThisFile, for example) + +For skeleton structure of executable, look at some of filesystems +similar to yours. + +--------------------------------------------------------- + +In constructing these routines, errors will be made, and mc will not display +a malformed printing line. That can lead the programmer down many false +trails in search of the bug. Since this routine is an executable shell script +it can be run from the command line independently of mc, and its output will +show on the console or can be redirected to a file. + +* Putting it to use +---------------------------------------------------------- +The file .mc.ext in a home directory, and in mc's user directory (commonly +/etc/mc), contains instructions for operations on files depending +on filename extensions. It is well documented in other files in this +distribution, so here are just a few notes specifically on use of the +Virtual File System you just built. + +There are entries in .mc.ext defining a few operations that can be done on a +file from an mc panel. Typically they are annotated with a hash mark and a +file extension like this: + +# zip + +There must be a way to find the file by extension, so the next line does +that. In essence it says "identify the string ".zip" or (|) ".ZIP" at the +end ($) of a filename": + +regex/\.(zip|ZIP)$ + +The operations themselves follow that. They must be indented by at least a +space, and a tab works as well. In particular, the Open operation will +now use your new virtual file system by cd'ing to it like this: + + Open=%cd zip:%d/%p + +This is the line used when a file is highlighted in a panel and the user +presses or . The contents of the archive should show just +as if they were in a real directory, and can be manipulated as such. +The rest of the entry pertains to use of the F3 View key: + + View=%view{ascii} unzip -v %f + +And perhaps an optional icon for X: + + Icon=zip.xpm + +And perhaps an operation to extract the contents of the file, called from +a menu selection: + + Extract=unzip %f '*' + +This is just an example. The current entry for .zip files has a menu selection +of 'Unzip' which could be used in place of 'Extract'. What goes here depends +on what items you have in, or add to, the menu system, and that's another +subject. The sum of this is the .mc.ext entry: + +# zip +regex/\.(zip|ZIP)$ + Open=%cd %p/uzip:// + View=%view{ascii} unzip -v %f + Icon=zip.xpm + Extract=unzip %f '*' + +Add an entry like this to the .mc.ext file in a user's home directory, If you +want others to have it, add it to the mc.ext file in the mc system directory, +often /etc/mc/mc.ext. Notice this file is not prepended with a dot. + +Once all this is done, and things are in their proper places, exit mc if you +were using it, and restart it so it picks up the new information. + +That's all there is to it. The hardest part is making a listing function +that sorts the output of a system listing command and turns it into a form +that mc can use. Currently awk (or gawk) is used because nearly all systems +have it. If another scripting language is available, like perl, that could +also be used. -- cgit v1.2.3