pax_global_header00006660000000000000000000000064147011203270014507gustar00rootroot0000000000000052 comment=ec342280389f14bf8e9aadc7947a41a726d06061 fusefile-2.0/000077500000000000000000000000001470112032700131525ustar00rootroot00000000000000fusefile-2.0/.gitweb000066400000000000000000000001311470112032700144270ustar00rootroot00000000000000description = FUSE file mount combining fragments of files as a file. category = goodies fusefile-2.0/LICENSE000066400000000000000000001044051470112032700141630ustar00rootroot00000000000000 GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 Copyright (C) 2007 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The GNU General Public License is a free, copyleft license for software and other kinds of works. The licenses for most software and other practical works are designed to take away your freedom to share and change the works. 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IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 17. Interpretation of Sections 15 and 16. If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee. END OF TERMS AND CONDITIONS How to Apply These Terms to Your New Programs If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. fusefile Copyright (C) 2019 Ralph Ronnquist This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Also add information on how to contact you by electronic and paper mail. If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode: fusefile Copyright (C) 2019 Ralph Ronnquist This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an "about box". You should also get your employer (if you work as a programmer) or school, if any, to sign a "copyright disclaimer" for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see . The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read . fusefile-2.0/Makefile000066400000000000000000000014421470112032700146130ustar00rootroot00000000000000BINS = fusefile default: $(BINS) ifneq (${DEBUG},) ${BINS}: CFLAGS += -DDEBUG=1 -g endif ${BINS}: CFLAGS += -Wall -D_FILE_OFFSET_BITS=64 fusefile: LDFLAGS = -lfuse3 -pthread .INTERMEDIATE: fusefile.o fusefile.o: fusefile.c fusefile: fusefile.o $(CC) $(CFLAGS) $(CPPFLAGS) $? $(LDFLAGS) $(TARGET_ARCH) -o $@ clean: rm -f $(BINS) README.html: README.adoc asciidoctor $< > $@ # Building a debian package SBINDIR = $(DESTDIR)/usr/sbin MAN8DIR = $(DESTDIR)/usr/share/man/man8 SBINFILES = fusefile fusedisk MAN8FILES = fusefile.8 INSTALLTARGETS = $(addprefix $(SBINDIR)/,$(SBINFILES)) INSTALLTARGETS += $(addprefix $(MAN8DIR)/,$(MAN8FILES)) $(SBINDIR)/% $(MAN8DIR)/%: % install -D -T $< $@ install: $(INSTALLTARGETS) deb: PREFIX= INCLUDE_PREFIX=/usr dpkg-buildpackage --build=full -uc -us fusefile-2.0/README.adoc000066400000000000000000000013101470112032700147320ustar00rootroot00000000000000# fusefile :author: Ralph Ronnquist :revdate: Sun, 30 Apr 2023 21:18:34 +1000 This project implements a "fuse" device to mount a concatenation of fragments of one or more files as a single file. The __fused file__ allows writing to fragments (without changing their sizes); of course only for writable fragment files. The fused file may be set up with an __overlay file__ to capture changes instead of writing the underlying fragment files. ==== This is a usage example to set up a fused file C consisting of files A and B: ---- $ fusefile C A B ---- ==== ==== This is an example of tearing down a fused file C: ---- $ fusermount -u C ---- ==== See the +man page+ for usage details and some more examples. fusefile-2.0/asynctest.lsp000077500000000000000000000037721470112032700157230ustar00rootroot00000000000000#!/usr/bin/newlisp # # This is a test script for the overlay function of fusefile. # # 1) prepare a base image # 2) set up a fusefile # 3) run tests # 4) dismantle the fusefile # 5) remove test images ; ID is hour, minute and second values packed into a string (constant 'ID (apply string (3 3 (now))) 'BASE (format "%s.raw" ID) 'SEGSZ 17000 'SEGN 40 'FILE (join (map (fn (R) (format "%s/%d:%d" (cons BASE R))) (map (curry map (curry * SEGSZ) R) '((14 22) (0 3) (22 40) (3 22)))) " ") 'LIBC6 "/lib/x86_64-linux-gnu/libc.so.6" 'MINE "mine" ) (import LIBC6 "on_exit" "int" "void*" "void*") ;; BASE is set up as a holes file with SEGN segments of size SEGSZ (! (format "dd if=/dev/zero of=%s bs=%d seek=%d count=0 status=none" BASE SEGSZ SEGN)) ;; Set up the fusefile (unless (= (! (format "fusefile %s %s %s" "-ononempty -oallow_other" BASE FILE))) (exit 1)) (println (list BASE FILE)) (define (writer CODE ADDR) (println "writer " (char (CODE 0)) " " ADDR) (let ((FD (open BASE "u"))) (when (> FD) (seek FD ADDR) (write FD CODE) (close FD)))) (define (reader CODE ADDR) (println "reader " (char (CODE 0)) " " ADDR) (let ((FD (open BASE "u")) (TODO (length CODE)) (BUFFER "") (B "")) (if (when (> FD) (seek FD ADDR) (while (and (> TODO) (> (setf N (read FD B TODO)))) (extend BUFFER B) (dec TODO (length B))) (close FD) (and (= TODO) (= CODE BUFFER))) (println "reader " (char (CODE 0)) " done") (println "reader " (char (CODE 0)) " failed") ))) (define (forking FN I) (letex ((FN FN) (CODE (dup (char I) (/ SEGSZ 2))) (ADDR (* (- I 1) SEGSZ))) (fork (FN CODE ADDR)))) (map wait-pid (map (curry forking writer) (sequence 1 SEGN))) (map wait-pid (map (curry forking reader) (sequence 1 SEGN))) ;; On exit: unmount the fusefile and delete the BASE (! (format "fusermount -u %s" BASE)) (delete-file BASE) (exit 0) fusefile-2.0/fusedisk000077500000000000000000000024011470112032700147120ustar00rootroot00000000000000#!/bin/sh # # Set up a fusefile as a disk device using device mapper. # Note that this requires root access. if [ $(id -u) != 0 ] ; then echo "block device set up requires root." >&2 exit 1 fi # fuse blkdev mounting needs to sniff an existing but unmounted block # device node for setup. However the device mapping has an empty table # and the content is only accessible via the fuse mount that links it # to the fusefile process. The device node (major:minor) are still # considered in use by the kernel and, and the device node is "open" # while mounted. [ -e /dev/mapper/control ] || modprobe dm_mod || exit 1 # Create up to N fusedisk named as fusedisk0..fusediskN, the device # mapper also creates its dm-X device nodes and we also force # /dev/mapper/$NAME nodes for them. N=15 DEV= for I in $(seq 0 $N) ; do NAME=fusedisk$I C="$(dmsetup info --noheadings -c -o open $NAME 2>/dev/null)" if [ "$C" != "1" ] ; then if [ -z "$C" ] ; then dmsetup create $NAME --notable || exit 1 dmsetup mknodes $NAME || exit 1 fi DEV=/dev/mapper/$NAME break fi done if [ -z "$DEV" ] ; then echo "** No more fusedisk devices" >&2 exit 1 fi echo "using $DEV for $*" | logger -t fusedisk exec fusefile -oblkdev,fsname=$DEV -oallow_other $* fusefile-2.0/fusefile.8000066400000000000000000000210621470112032700150460ustar00rootroot00000000000000.mso www.tmac .TH fusefile 8 .SH NAME fusefile, fusedisk \- FUSE file mount for combining file fragments .SH SYNOPSIS .B fusefile \fR[\fIfuse-opts\fR] \fBmountpoint\fR \fR[\fIoverlay\fR] \fIfilename/from-to\fR ... .br .B fusefile \fB-dump\fR \fR[\fIfuse-opts\fR] \fBmountpoint\fR \fR[\fIoverlay\fR] \fIfilename/from-to\fR ... .br .B fusefile \fB-push\fR \fR[\fIfuse-opts\fR] \fBmountpoint\fR \fR[\fIoverlay\fR] \fIfilename/from-to\fR ... .br .B fusedisk \fR[\fIfuse-opts\fR] \fBmountpoint\fR \fR[\fIoverlay\fR] \fIfilename/from-to\fR ... .SH DESCRIPTION \fBfusefile\fR is a FUSE \fIfile mount\fR that presents a series of fragments of other files as a contiguous concatenation. Technically it bind mounts a driver on top of the filename mountpoint to provide access to the given file fragments as if in a single, contiguous file. \fBfusefile\fR accepts over-writing on the fused file (i.e. the mountpoint) which gets distributed accordingly to the fragments. But neither the fused file nor the fragments can change size; any writing thus merely over-writes content without truncating fragments. All fragment files are held open while \fBfusefile\fR is active. By using the optional \fB-overlay:\fIfilename\fR argument between the mount point and the fragments, an overlay file may be set up. The overlay file will then be used by \fBfusefile\fR for capturing writes to the fused file (i.e. the mountpoint). The overlay file will contain any new written fused file regions followed by meta data to distinguish between new, written content and old content that comes from the fragments. By instead using the \fB-overlay:\fIlist\fR argument where \fIlist\fR is a colon-separated list of filenames, \fBfusefile\fR will use those as an ordered stack of overlays and "inject" them as fragments on top of each other. The option \fB-dump\fR as first argument together with a fusefile setup will print the setup to standard output rather than establishing a fusefile mount. This is of most use with a prior overlay setup where then the printout includes the portions of updates that have been captured in the overlay. The printout is the series of fusefile fragment argments to give in order to intersperse the captured overlay portions according to the overlay table. The option \fB-push\fR as first argument together with a fusefile setup will push the overlay into the sources (except for write-protected fragments). This is only of use with a prior overlay setup where then the updates that have been captured in the overlay get pushed into the fragments. \fBfusedisk\fR is a helper script to set up a \fBfusefile\fR as a block device (via \fIfuseblk\fR) by using the device mapper (\fBdmsetup\fR) to manage an empty block device mapping where content is handled at the mountpoint via \fBfusefile\fR. (Note that the same thing may be done with the device manager directly, but then all fragments need to be in sectors of N*512 bytes whereas with \fBfusedisk\fR, only the fused file as a whole is "clipped" at nearest N*512 bytes below actual size) .SH FRAGMENT ARGUMENTS The fragment arguments include the filename of a source file, and optionally start and end byte positions. All in all there five variations: .TP \fIfilename\fR or \fIfilename/\fR include all of the file. A pathname that includes "/" must be ended with an extra "/" since that last "/" separates the filename from the range detail. .TP \fIfilename/start:end\fR include the range from the given start to end. Either "start" or "end" or both may be omitted, to mean the beginning and end of the file respectively. If "start" or "end" are less than 0 then it means relative to the end of the file. .TP \fIfilename/start+length\fR include "length" bytes from the given start. A negative "start" means relative to the end of the file. If "length" is negative or omitted it means that position relative to the end. .TP \fIfilename/start\fR include bytes from the given start. This is the same as "/start+" .P Note that a negative start position is clipped to 0 and a too large end position is clipped to the end of the file. .P Character devices are treated as being of any given finite size, but have size 0 by default. For example, "/dev/zero/:100" means a fragment of 100 NUL bytes. .SH OPTIONS This section enumerates the most interesting options to use with \fBfuesfile\fR. See "man fuse" and "man mount" for more options. .TP \fB-dump\fR The \fB-dump\fR "option" tells \fBfusefile\fR to print out the applicable fragment sequence for the current setup, including the overlay table, if any. The printout is done instead of setting up a mount point. .TP \fB-o\fIallow_other\fB The fuse option \fI-oallow_other\fR is needed for sharing the fused file with other users who otherwise will not have access to it (including "root"). Note however that this must first be enabled in \fI/etc/fuse.conf\fR. .TP \fB-o\fInonempty\fR The fuse option \fI-ononempty\fR may need to be used when reusing an existing file as mountpoint. .TP \fB-o\fIuid=...\fR and \fB-o\fIgid=...\fR, These mount options, where \fI...\fR is a user or group id respectively, are useful for root when using \fBfusedisk\fR and thereby give user or group ownership for the mount to the nominated user or group. .SH EXAMPLES This section illustrates uses of \fBfusefile\fR. .SS Exanple 1. Insert a file "y" into a file "x" at position 1200. .RS \fB$ fusefile -ononempty x x/:1200 y x/1200:\fR .RE This also shadows the original file "x" and presents the fused file instead. .SS Example 2. Make fused file y be a swap of the beginning and end of file "x", at position 2442. .RS \fB$ fusefile y x/2442: x/:2442\fR .RE .SS Example 3. Replace partition 2 of an image file, \fIA\fR, with a different file, \fIX\fR. For this example the partition table looks as follows. .RS \fB$ partx -oNR,START,SECTORS \fIA\fR NR START SECTORS 1 2048 2097152 2 2099200 409600 3 2508800 14268383 .RE .br As each sector is 512 bytes the clipping points around partition 2 are 1074790400 and 1284505600 and the insertion size is 209715200 bytes. The \fBfusefile\fR comman will therefore be as follows. .RS \fB$ fusefile -ononempty \fIA\fB \fIA\fB/:1074790400 \fIX\fB/:209715200 \fIA\fB/1284505600\fR .RE Note that the fused file shadows the original file \fIA\fR. .SS Example 4. Protect raw disk image file with an overlay: .RS \fB$ fusefile -ononempty disk.raw -overlay:today disk.raw\fR .RE By that set up, the overlay file, "today", will protect the disk image file, "disk.raw" from changes, and also override the pathname "disk.raw" to be the fused file. .SS Example 5. A fusefile mount with an \fIoverlay file\fR is writable regardless of the fused fragments, but all updates are written to the overlay file instead of to the fragments. .RS \fB$ fusefile -ononempty \fIA\fR \fB-overlay:\fIB\fB \fIA\fR .RE The overlay file, \fIB\fR in the example, contains all changes to the shadowed original file, \fIA\fR. The overlay file contains only the newly written regions and content is otherwise obtained from the original file. To that end, the overlay file also contains a "marker table" at the end as if appended to the fused file. That part of the file is outside of the fused file; and it's simply an element count followed by pairs of byte addresses that tell which regions of the fused file have been captured into the overlay file. (The marker table is of course maintained so that adjoining regions are collapsed) Thus, an overlay file may be reused to later re-establish the same fused file with overlay as previously, to continue capturing more changes. .SS Example 6. As final example, we set up a fused block device \fIy\fR as a swap of the beginning and end of file "x", at position 2442: .RS \fB$ sudo fusedisk -ouid=1000 y x/2442: x/:2442\fR .RE Note the use of \fBsudo\fR for becoming \fIroot\fR, which is required for block device handling, and also the \fB-ouid=1000\fR option so as to make the block device \fIy\fR be owned by the user with id 1000. .SH NOTES \fBfusefile\fR opens the nominated source files before any bind mounting. With the fuse option \fI-ononempty\fR it will bind over an non-empty file, which may be useful. The source files remain open, but the source fragments are not recomputed. If a source file changes the fused file will present the new content. If a source is reduced in size, access will be inconsistent. If the mountpoint file doesn't exist, then \fBfusefile\fR creates it. Unmounting is done with "\fBfusermount -u\fR \fImountpoint\fR" as usual. A \fBfusedisk\fR mount is unmounted by \fIroot\fR using \fBumount\fR. .SH SEE ALSO \fBfuse, fusermount, mount, dmsetup\fR .SH AUTHOR Ralph Rönnquist . fusefile-2.0/fusefile.c000066400000000000000000000743451470112032700151350ustar00rootroot00000000000000/*** fusefile - overlay a file path with a concatenation of parts of other files. Copyright (C) 2019- Ralph Ronnquist This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . This source was inspired by the "null.c" example of the libfuse sources, which is distributed under GPL2, and copyright (C) 2001-2007 Miklos Szeredi . */ #define FUSE_USE_VERSION 33 #include #include #include #include #include #include #include #include #include #include struct Region { off_t beg; off_t end; }; #define REGIONKEEP(r) ((r,beg == r.end)?: 0 : 1) struct Source { char *filename; ssize_t from; ssize_t to; ssize_t start; // starting position in concatenated file int fd; int dirty; }; #define ENDSOURCE( S ) ( S.start + ( S.to - S.from ) ) static struct { struct Source *array; int count; ssize_t size; } sources; static struct { time_t atime; time_t mtime; time_t ctime; } times; /** * Overlay */ static struct Overlay { struct Source source; struct Region *table; size_t count; size_t limit; } overlay; // The current overlay. static void usage(); /** * Find the nearest overlay.table region below pos. Returns the index, * or -1 if there is none, i.e. pos < overlay.table[0]. */ static ssize_t overlay_prior_fragment(off_t pos) { size_t lo = 0, hi = overlay.count; while ( lo < hi ) { size_t m = ( lo + hi ) / 2; if ( m == lo ) { return overlay.table[m].beg <= pos? m : -1; } if ( overlay.table[m].beg <= pos ) { lo = m; } else { hi = m; } } return -1; } /** * Save the entry count for overlay.table as 64-bit integer * immediately following the overlay content at the index * corresponding to the fused file size. */ static void overlay_save_count() { lseek( overlay.source.fd, overlay.source.to, SEEK_SET ); size_t size = sizeof( overlay.count ); char *p = (char *) &overlay.count ; while ( size > 0 ) { size_t n = write( overlay.source.fd, p, size ); if ( n < 0 ) { perror( overlay.source.filename ); exit( 1 ); } size -= n; p += n; } if ( overlay.source.dirty++ > 1000 ) { fsync( overlay.source.fd ); overlay.source.dirty = 0; } } /** * Update the on-disk cache of overlay.table between the given * indexes. The table is laid out immediately following the table * count with each region saved as two 64-bit unsigned integers. */ static void overlay_save_table(size_t lo,size_t hi) { char *p = (char *) &overlay.table[ lo ]; size_t pos = overlay.source.to + sizeof( overlay.count ) + lo * sizeof( struct Region ); size_t size = ( hi - lo ) * sizeof( struct Region ); if ( pos != lseek( overlay.source.fd, pos, SEEK_SET ) ) { fprintf( stderr, "%s: seek error\n", overlay.source.filename ); exit( 1 ); } while ( size > 0 ) { size_t n = write( overlay.source.fd, p, size ); if ( n < 0 ) { perror( overlay.source.filename ); exit( 1 ); } size -= n; p += n; } if ( overlay.source.dirty++ > 1000 ) { fsync( overlay.source.fd ); overlay.source.dirty = 0; } } /** * Insert a new region at index p, with previous portion [p,count] * moved up to make space. */ static void overlay_insert(size_t p,off_t beg,off_t end) { size_t bytes; // Grow the table if needed if ( overlay.count >= overlay.limit ) { overlay.limit = overlay.count + 10; bytes = overlay.limit * sizeof( struct Region ); overlay.table = overlay.table? realloc( overlay.table, bytes ) : malloc( bytes ); } bytes = ( overlay.count++ - p ) * sizeof( struct Region ); if ( bytes ) { memmove( (char*) &overlay.table[ p+1 ], (char*) &overlay.table[ p ], bytes ); } overlay.table[ p ].beg = beg; overlay.table[ p ].end = end; overlay_save_count(); } /** * Delete the region entry at p by moving the portion [p+1,count] * down. */ static void overlay_delete(size_t p) { size_t bytes = ( --overlay.count - p ) * sizeof( struct Region ); if ( bytes ) { memmove( (char*) &overlay.table[ p ], (char*) &overlay.table[ p+1 ], bytes ); } } /** * Mark the given region as updated, i.e. written to the overlay. The * mark region may attach to prior marked regions or be a new, * separate region. If attaching, it causes the prior regions to * expand and the table adjusted by deleting any regions that become * fully contained in other regions. */ static void overlay_mark(off_t beg,off_t end) { #if DEBUG fprintf( stderr, "overlay_mark( %ld, %ld )\n", beg, end ); #endif int deleted = 0; ssize_t q; ssize_t p = overlay_prior_fragment( beg ); // p is the nearest region below or at beg (or -1) if ( p >= 0 && beg <= overlay.table[p].end ) { // p overlaps mark region if ( end <= overlay.table[p].end ) { // region p covers mark region already #if DEBUG fprintf( stderr, "overlay covering ( %ld %ld )\n", overlay.table[p].beg, overlay.table[p].end ); #endif return; } // the new mark region extends region p overlay.table[p].end = end; q = p+1; while ( q < overlay.count && overlay.table[q].beg <= overlay.table[p].end ) { // Extended region merges with subsequent region if ( overlay.table[p].end < overlay.table[q].end ) { overlay.table[p].end = overlay.table[q].end; } overlay_delete( q ); deleted++; } if ( deleted ) { overlay_save_count(); q = overlay.count; } overlay_save_table( p, q ); #if DEBUG fprintf( stderr, "overlay expand ( %ld %ld ) deleted %d\n", overlay.table[p].beg, overlay.table[p].end, deleted ); #endif return; } // The prior region p does not expand into new mark region p++; // subsequent region if ( p >= overlay.count || end < overlay.table[p].beg ) { // New mark region is a separate region at p overlay_insert( p, beg, end ); #if DEBUG fprintf( stderr, "overlay new ( %ld %ld )\n", overlay.table[p].beg, overlay.table[p].end ); #endif overlay_save_table( p, overlay.count ); return; } // New marks start before and overlap with region p => change p // and handle any subsequent regions being covered overlay.table[p].beg = beg; q = p+1; if ( overlay.table[p].end < end ) { overlay.table[p].end = end; while ( q < overlay.count && overlay.table[q].beg <= overlay.table[p].end ) { if ( overlay.table[p].end < overlay.table[q].end ) { overlay.table[p].end = overlay.table[q].end; } overlay_delete( q ); deleted++; } if ( deleted ) { overlay_save_count(); q = overlay.count; } } overlay_save_table( p, q ); #if DEBUG fprintf( stderr, "overlay before ( %ld %ld ) deleted %d\n", overlay.table[p].beg, overlay.table[p].end, deleted ); #endif } /** * Capture overlay filenames for processing after source fragments. */ static void overlay_setup(char *filenames) { overlay.source.filename = filenames; } // Duplicate the source record data at the given index. static void dup_source_item(int index) { sources.count++; sources.array = realloc( sources.array, sources.count * sizeof( struct Source ) ); if ( sources.array == 0 ) { fprintf( stderr, "** OOM when expanding frament table\n" ); usage(); } // copy elements from [index] to [count-1] one element down size_t size = ( sources.count - index - 1 ) * sizeof( struct Source ); memmove( &sources.array[ index+1 ], &sources.array[ index ], size ); } #if DEBUG static void print_source(struct Source *p) { fprintf( stderr, "%p { %s, %ld, %ld, %ld, %d }\n", p, p->filename, p->from, p->to, p->start, p-> fd ); } #endif static char *range; static unsigned int c; static int RANGE(int s,int n ) { return ( s == n ) && *(range+c) == 0; } static int setup_source(struct Source *p,char *frag) { struct stat filestat; // Open the fragment file rw if possible, else ro // First try the fragment in full, thereafter with range appendix if ( stat( frag, &filestat ) == 0 ) { p->filename = strdup( frag ); range = 0; } else { range = strrchr( frag, '/' ); // last '/' p->filename = range? strndup( frag, range - frag ) : frag; } p->fd = open( p->filename, O_RDWR ); int rdonly = 0; if ( p->fd < 0 ) { rdonly = 1; p->fd = open( p->filename, O_RDONLY ); } if ( p->fd < 0 ) { perror( p->filename ); return 1; // Error return } if ( ( range != 0 ) && stat( p->filename, &filestat ) ) { perror( p->filename ); return 1; } if ( rdonly ) { fprintf( stderr, "** %s opened read-only\n", p->filename ); } p->from = 0; if ( S_ISBLK( filestat.st_mode ) ) { // Block devices report size differently: if ( ioctl( p->fd, BLKGETSIZE64, &filestat.st_size ) < 0 ) { perror( p->filename ); } #if DEBUG fprintf( stderr, "block device size = %ld\n", filestat.st_size ); #endif } p->to = filestat.st_size; // Process any range variation if ( range && *(++range) ) { long int a,b; if ( 0 ) { } else if ( RANGE( sscanf( range, "%ld:%ld%n", &a, &b, &c ), 2 )) { p->from = ( a < 0 )? ( p->to + a ) : a; p->to = ( b < 0 )? ( p->to + b ) : b; } else if ( RANGE( sscanf( range, "%ld+%ld%n", &a, &b, &c ), 2 )) { p->from = ( a < 0 )? ( p->to + a ) : a; p->to = ( ( b < 0 )? p->to : p->from ) + b; } else if ( RANGE( sscanf( range, "%ld+%n", &a, &c ), 1 )) { p->from = ( a < 0 )? ( p->to + a ) : a; } else if ( RANGE( sscanf( range, ":%ld%n", &b, &c ), 1 )) { p->to = ( b < 0 )? ( p->to + b ) : b; } else if ( RANGE( sscanf( range, "%ld:%n", &a, &c ), 1 )) { p->from = ( a < 0 )? ( p->to + a ) : a; } else if ( RANGE( sscanf( range, "%ld%n", &a, &c ), 1 )) { if ( a >= 0 ) { p->from = a; } else { p->from = p->to + a; } } else if ( RANGE( sscanf( range, ":%n", &c), 0 ) ) { // to end from start } else { fprintf( stderr, "** BAD RANGE: %s\n", frag ); return 1; } } if ( ( filestat.st_mode & S_IFMT ) == S_IFCHR ) { filestat.st_size = p->to; // Pretend size of character device } if ( p->from < 0 ) { p->from = 0; } if ( p->to > filestat.st_size ) { p->to = filestat.st_size; } if ( p->from >= p->to || p->from >= filestat.st_size ) { fprintf( stderr, "** BAD RANGE: %s [%ld:%ld]\n", frag, p->from, p->to ); return 1; } p->start = sources.size; // the fusefile position of fragment sources.size += p->to - p->from; return 0; } static int setup_sources(char **argv,int i,int n) { sources.array = calloc( n, sizeof( struct Source ) ); if ( sources.array == 0 ) { return 1; } sources.count = n; int j = 0; sources.size = 0; for ( ; j < n; i++, j++ ) { struct Source *p = sources.array + j; if ( setup_source( p, argv[i] ) ) { return 1; } #if DEBUG print_source( p ); #endif } return 0; } static int fusefile_getattr(const char *path, struct stat *stbuf, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_getattr( %s )\n", path ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } #if DEBUG fprintf( stderr, "getattr %ld\n", sources.size ); #endif memset( stbuf, 0, sizeof( struct stat ) ); stbuf->st_mode = S_IFREG | 0644; // Hmmm stbuf->st_nlink = 1; stbuf->st_size = sources.size; stbuf->st_atime = times.atime; stbuf->st_mtime = times.mtime; stbuf->st_ctime = times.ctime; stbuf->st_uid = getuid(); stbuf->st_gid = getgid(); return 0; } static int fusefile_chmod(const char *path, mode_t m, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_chmod( %s, %d )\n", path, m ); #endif return -1; } static int fusefile_open(const char *path, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_open( %s, %d )\n", path, ffi->flags ); fprintf( stderr, "fixing( %d )\n", ffi->flags | O_CLOEXEC ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } // set O-CLOEXEC for this opening? times.atime = time( 0 ); return 0; } static int find_source(off_t offset) { int lo = 0; int hi = sources.count; if ( offset >= sources.size ) { return -1; } while ( lo + 1 < hi ) { int m = ( lo + hi ) / 2; if ( offset < sources.array[ m ].start ) { hi = m; } else { lo = m; } } return lo; } static int overlay_merge(char *buf,off_t beg,off_t end) { #if DEBUG fprintf( stderr, "merge %ld %ld\n", beg, end ); #endif // Find nearest overlay data before or at beg ssize_t p = overlay_prior_fragment( beg ); if ( p < 0 ) { p = 0; } for ( ; p < overlay.count && overlay.table[p].beg < end; p++ ) { if ( overlay.table[p].end < beg ) { continue; } if ( overlay.table[p].beg > beg ) { size_t delta = overlay.table[p].beg - beg; buf += delta; beg += delta; } size_t size = ( overlay.table[p].end <= end )? ( overlay.table[p].end - beg ) : ( end - beg ); lseek( overlay.source.fd, beg, SEEK_SET ); while ( size > 0 ) { size_t n = read( overlay.source.fd, buf, size ); size -= n; buf += n; beg += n; // } } return 0; } // Read bytes from in file static int fusefile_read(const char *path, char *buf, size_t size, off_t off, struct fuse_file_info *ffi) { if( strcmp( path, "/" ) != 0 ) { return -ENOENT; } size_t rr = 0; // total reading #if DEBUG fprintf( stderr, "fusefile_read %ld + %ld\n", off, size ); #endif while ( size > 0 ) { int i = find_source( off ); if ( i < 0 ) { return ( off == sources.size )? rr : -ENOENT; } #if DEBUG fprintf( stderr, " item: %d ", i ); print_source(& sources.array[i] ); #endif if ( sources.array[i].fd < 0 ) { return -ENOENT; } times.atime = time( 0 ); size_t b = off - sources.array[i].start + sources.array[i].from; size_t n = sources.array[i].to - b; if ( n > size ) { n = size; } if ( sources.array[i].dirty ) { fsync( sources.array[i].fd ); sources.array[i].dirty = 0; } if ( lseek( sources.array[i].fd, b, SEEK_SET ) < 0 ) { perror( sources.array[i].filename ); return -ENOENT; } ssize_t r = read( sources.array[i].fd, buf + rr, n ); #if DEBUG fprintf( stderr, " got: %ld bytes of %ld at %ld\n", r, n, rr ); #endif if ( r < 0 ) { perror( sources.array[i].filename ); return -ENOENT; } if ( r == 0 ) { break; } if ( overlay.source.filename ) { if ( overlay.source.dirty ) { fsync( overlay.source.fd ); overlay.source.dirty = 0; } int x = overlay_merge( buf + rr, off + rr, off + rr + r ); if ( x ) { return x; } } rr += r; off += r; size -= r; } #if DEBUG fprintf( stderr, " total reading %ld bytes\n", rr ); #endif return rr; } /** * Poll for IO readiness. */ int fusefile_poll(const char *path, struct fuse_file_info *ffi, struct fuse_pollhandle *ph, unsigned *reventsp ) { #if DEBUG fprintf( stderr, "fusefile_poll( %s ) %p %d\n", path, ph, *reventsp ); #endif if( strcmp( path, "/" ) != 0 ) { return -ENOENT; } if ( ph ) { return fuse_notify_poll( ph ); } return 0; } static void overlay_load() { lseek( overlay.source.fd, overlay.source.to, SEEK_SET ); size_t x = 0; size_t size = sizeof( overlay.count ); if ( read( overlay.source.fd, &x, size ) != size ) { return; } #if DEBUG fprintf( stderr, "overlay: %s with %ld regions\n", overlay.source.filename, x ); #endif struct Region f = { 0, 0 }; size = sizeof( struct Region ); while ( x-- > 0 ) { if ( read( overlay.source.fd, &f, size ) != size ) { fprintf( stderr, "%s: bad meta data\n", overlay.source.filename ); exit( 1 ); } #if DEBUG fprintf( stderr, "overlay region: %ld %ld\n", f.beg, f.end ); #endif overlay_mark( f.beg, f.end ); } } /** * Inject an overlay fragment into the source table, end return the * end of the injected fragment. */ static off_t overlay_inject_from_region(off_t beg,off_t end) { int index = find_source( beg ); if ( index < 0 ) { fprintf( stderr, "** Injecting %s at %ld failed\n", overlay.source.filename, beg ); usage(); } if ( end > ENDSOURCE( sources.array[ index ] ) ) { end = ENDSOURCE( sources.array[ index ] ); } struct Region frags[3] = { { sources.array[ index ].start, beg }, { beg, end }, { end, ENDSOURCE( sources.array[ index ] ) } }; #if DEBUG int i; for ( i = 0; i < 3; i++ ) { fprintf( stderr, "frags[%d] = (%ld, %ld)\n", i, frags[i].beg, frags[i].end ); } #endif ssize_t size = frags[0].end - frags[0].beg; if ( size ) { // Handle any portion before injection point. dup_source_item( index ); off_t point = sources.array[ index ].from + size; sources.array[ index ].to = point; #if DEBUG fprintf( stderr, "item %d ", index ); print_source( &sources.array[ index ] ); #endif // Adjust item after injection point index++; sources.array[ index ].start = beg; sources.array[ index ].from = point; #if DEBUG fprintf( stderr, "item %d adjust ", index ); print_source( &sources.array[ index ] ); #endif } size = frags[2].end - frags[2].beg; if ( size ) { // Handle any remaining portion following injection fragment dup_source_item( index ); sources.array[ index+1 ].start = frags[2].beg; sources.array[ index+1 ].from += frags[1].end - frags[1].beg; #if DEBUG fprintf( stderr, "item %d ", index+1 ); print_source( &sources.array[ index+1 ] ); #endif } // Set up the injection fragment sources.array[ index ].filename = overlay.source.filename; sources.array[ index ].from = beg; sources.array[ index ].to = end; sources.array[ index ].fd = overlay.source.fd; #if DEBUG fprintf( stderr, "item %d ", index ); print_source( &sources.array[ index ] ); #endif return end; } /** * Inject the current (unopened) overlay into the source list. */ static void overlay_inject() { overlay.source.fd = open( overlay.source.filename, O_RDONLY ); if ( overlay.source.fd < 0 ) { perror( overlay.source.filename ); usage(); } if ( lseek( overlay.source.fd, overlay.source.to, SEEK_SET ) < 0 ) { perror( overlay.source.filename ); usage(); } size_t count = 0; size_t size = sizeof( overlay.count ); size_t n; if ( ( n = read( overlay.source.fd, &count, size ) ) != size ) { if ( n != 0 ) { fprintf( stderr, "** error injecting %s\n", overlay.source.filename ); usage(); } fprintf( stderr, "** ignoring empty %s\n", overlay.source.filename ); } if ( count == 0 ) { close( overlay.source.fd ); return; } size = count * sizeof( struct Region ); overlay.table = calloc( sizeof( struct Region ), count ); if ( read( overlay.source.fd, overlay.table, size ) != size ) { fprintf( stderr, "** error injecting %s\n", overlay.source.filename ); usage(); } size_t i; for ( i = 0; i < count; i++ ) { off_t beg = overlay.table[i].beg; while ( beg < overlay.table[i].end ) { #if DEBUG fprintf( stderr, "inject [%ld,%ld] ", beg, overlay.table[i].end ); print_source( &overlay.source ); #endif beg = overlay_inject_from_region( beg, overlay.table[i].end ); } } free( overlay.table ); overlay.table = 0; } /** * Each stacked overlay file is nested into to source list */ static void overlay_post_setup() { char *end; while ( ( end = strchr( overlay.source.filename, ':' ) ) ) { *end = 0; // overlay_inject(); overlay.source.filename = end + 1; } if ( *overlay.source.filename ) { overlay.source.fd = open( overlay.source.filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR ); if ( overlay.source.fd < 0 ) { perror( overlay.source.filename ); usage(); } overlay_load(); } } /** * Write a full block of data over the sources at the offset */ static int write_block(off_t off,const char *buf,size_t size) { #if DEBUG fprintf( stderr, "write_block( %ld, ?, %ld )\n", off, size ); #endif if ( overlay.source.filename ) { overlay_mark( off, off + size ); // Mark region as written } while ( size > 0 ) { int index = find_source( off ); // index of source file if ( index < 0 ) { return -EIO; // past EOF } struct Source *source = overlay.source.filename? &overlay.source : &sources.array[ index ]; off_t from = off - source->start + source->from; off_t max = source->to - from; if ( lseek( source->fd, from, SEEK_SET ) < 0 ) { return -EIO; } ssize_t todo = ( size < max )? size : max; while ( todo > 0 ) { times.mtime = time( 0 ); ssize_t n = write( source->fd, buf, todo ); if ( n <= 0 ) { return -EIO; // Something wrong } buf += n; todo -= n; size -= n; off += n; } if ( source->dirty++ >= 1000 ) { fsync( source->fd ); source->dirty = 0; } } return 0; } static int fusefile_write_buf(const char *path, struct fuse_bufvec *buf, off_t off, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_write_buf( %s )\n", path ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } size_t size = 0; int i; for ( i = 0; i < buf->count; i++ ) { struct fuse_buf *p = &buf->buf[i]; if ( p->flags & FUSE_BUF_IS_FD ) { #if DEBUG fprintf( stderr, "Content held in a file ... HELP!!\n" ); #endif return -EIO; } if ( write_block( off, (char*) p->mem, p->size ) < 0 ) { return -EIO; } size += p->size; } #if DEBUG fprintf( stderr, "fusefile_write_buf written %ld\n", size ); #endif return size; } /** * Write a fragment at . This overwrites files. */ static int fusefile_write(const char *path, const char *buf, size_t size, off_t off, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_write( %s %ld )\n", path, size ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } if ( write_block( off, buf, size ) < 0 ) { return -EIO; } return size; } #define PUSHBUF 104857600 /** * Write data from overlay to source. */ static void push_oly(off_t beg, off_t end) { static char * buffer = 0; // Pretend that there isn't an overlay char *filename = overlay.source.filename; if ( buffer == 0 ) { buffer = malloc( PUSHBUF ); if ( buffer == 0 ) { fprintf( stderr, "** OOM!!\n" ); exit( 1 ); } } overlay.source.filename = 0; while ( beg < end ) { off_t size = end - beg; if ( size > PUSHBUF ) { size = PUSHBUF; } if ( lseek( overlay.source.fd, beg, SEEK_SET ) < 0 ) { fprintf( stderr, "** Cannot seek overlay at %ld\n", beg ); break; } size = read( overlay.source.fd, buffer, size ); if ( write_block( beg, buffer, size ) < 0 ) { fprintf( stderr, "** Cannot push %ld bytes at %ld\n", size, beg ); } beg += size; } overlay.source.filename = filename; } static void fusefile_destroy(void *data) { char *mnt = (char*) data; // As passed to fuse_main #if DEBUG fprintf( stderr, "fusefile_destroy( %s )\n", mnt? mnt : "" ); #endif if ( mnt ) { unlink( mnt ); } } static void fsync_all_dirty() { int i = 0; for ( ; i < sources.count; i++ ) { if ( sources.array[i].dirty ) { fsync( sources.array[i].fd ); sources.array[i].dirty = 0; } } if ( overlay.source.filename && overlay.source.dirty ) { fsync( overlay.source.fd ); overlay.source.dirty = 0; } } static int fusefile_flush(const char *path, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_flush( %s )\n", path ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } fsync_all_dirty(); return 0; } static int fusefile_release(const char *path, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_release( %s, %d )\n", path, fi->flags ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } return 0; } static int fusefile_fsync(const char *path, int x, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_fsync( %s, %d )\n", path, x ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } fsync_all_dirty(); return 0; } /** * */ static int fusefile_truncate(const char *path, off_t len, struct fuse_file_info *ffi) { #if DEBUG fprintf( stderr, "fusefile_truncate( %s, %ld )\n", path, len ); #endif if ( strcmp( path, "/" ) != 0 ) { return -ENOENT; } return -EIO; } void *fusefile_init(struct fuse_conn_info *fci, struct fuse_config *fc) { #if DEBUG fprintf( stderr, "fusefile_init( %d, %d )\n", fci->async_read, fci->want ); #endif // Disable asynchronous operations, both reading and direct I/O fci->want &= ~ ( FUSE_CAP_ASYNC_READ | FUSE_CAP_ASYNC_DIO ); #if DEBUG fprintf( stderr, "fusefile_init( %d, %d )\n", fci->async_read, fci->want ); #endif return 0; } /** * Dump the current fragmentation to stdout. */ static int dump_fragments(int push) { int oly = 0; int src = 0; size_t pos = 0; while ( src < sources.count ) { size_t x = ( oly < overlay.count )? overlay.table[ oly ].beg : sources.size; for ( ; src < sources.count && ENDSOURCE( sources.array[ src ] ) <= x; src++ ) { // Dump sources.array[src] in full if ( !push ) { fprintf( stdout, "%s/%ld:%ld\n", sources.array[ src ].filename, pos - sources.array[ src ].start + sources.array[ src ].from, sources.array[ src ].to ); } pos = ENDSOURCE( sources.array[ src ] ); } if ( ( src < sources.count ) && ( sources.array[ src ].start < x ) ) { // Dump sources.array[src] up to x; if ( !push ) { fprintf( stdout, "%s/%ld:%ld\n", sources.array[ src ].filename, sources.array[ src ].from + pos - sources.array[ src ].start, x - sources.array[ src ].start + sources.array[ src ].from ); } pos = ENDSOURCE( sources.array[ src ] ); } if ( oly < overlay.count ) { if ( !push ) { fprintf( stdout, "%s/%ld:%ld\n", overlay.source.filename, overlay.table[ oly ].beg, overlay.table[ oly ].end ); } else { push_oly( overlay.table[ oly ].beg, overlay.table[ oly ].end ); } pos = overlay.table[ oly++ ].end; } for ( ; src < sources.count && ENDSOURCE( sources.array[ src ] ) <= pos; src++ ) { // Just skip these fragments. } } return( 0 ); } static struct fuse_operations fusefile_oper = { .getattr = fusefile_getattr, // NYI .fgetattr = fusefile_fgetattr, .chmod = fusefile_chmod, .open = fusefile_open, .read = fusefile_read, .poll = fusefile_poll, .write = fusefile_write, .write_buf = fusefile_write_buf, .destroy = fusefile_destroy, // NYI .access = fusefile_access, .flush = fusefile_flush, .release = fusefile_release, .fsync = fusefile_fsync, // NYI .ftruncate = fusefile_ftruncate, .truncate = fusefile_truncate, //.release = fusefile_release, .init = fusefile_init, }; static void usage() { char *usage = "Usage: fusefile [ ] ... \n" "Mounts a virtual, file that is a concatenation of file fragments\n" ; fprintf( stderr, "%s", usage ); exit( 1 ); } /** * Set up the arguments for the fuse_main call, adding our own. * argv[argc] is the mount point argument */ static int setup_argv(int argc,char ***argv) { // note: (*argv)[ argc ] is the mount point argument char *OURS[] = { "-odefault_permissions", //"-s", // Forced single-threading (*argv)[ argc ] }; #define OURSN ( sizeof( OURS ) / sizeof( char* ) ) int N = argc + OURSN; // Allocate new arg array plus terminating null pointer char **out = malloc( ( N + 1 ) * sizeof( char* ) ); int i; for ( i = 0; i < argc; i++ ) { out[ i ] = (*argv)[i]; //fprintf( stderr, " %s", out[ i ] ); } for ( i = 0; i < OURSN; i++ ) { out[ argc + i ] = OURS[i]; //fprintf( stderr, " %s", out[ i ] ); } out[ N ] = 0; //fprintf( stderr, "\n" ); (*argv) = out; return N; // Don't include the terminating null pointer } /** * Mount a concatenation of files, * [ ] ... */ int main(int argc, char *argv[]) { char *mnt; int i; int fuseargc; struct stat stbuf; int temporary = 0; // Scan past options for ( i = 1; i < argc; i++ ) { if ( *argv[i] != '-' ) { break; } } if ( i > argc - 2 ) { // At least mount point plus one source usage(); } fuseargc = i; mnt = argv[ i++ ]; // First non-option argument is the mount pount #define OVERLAYTAG "-overlay:" if ( strncmp( argv[i], OVERLAYTAG, strlen( OVERLAYTAG ) ) == 0 ) { // consume "-overlay:filename[,filename]*" overlay_setup( argv[i++] + strlen( OVERLAYTAG ) ); if ( i >= argc ) { usage(); } } if ( setup_sources( argv, i, argc-i ) ) { return 1; } if ( overlay.source.filename ) { overlay.source.to = sources.size; // Register total size. overlay_post_setup(); } if ( stat( mnt, &stbuf ) == -1 ) { int fd = open( mnt, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR ); if ( fd < 0 ) { perror( mnt ); return 1; } time_t now = time( 0 ); times.atime = now; times.mtime = now; times.ctime = now; temporary = 1; close( fd ); } else if ( ! S_ISREG( stbuf.st_mode ) ) { fprintf( stderr, "mountpoint is not a regular file\n" ); return 1; } else { times.atime = stbuf.st_atime; times.mtime = stbuf.st_mtime; times.ctime = stbuf.st_ctime; } { int fd = open( mnt, O_RDWR, S_IRUSR | S_IWUSR ); if ( fd < 0 ) { perror( mnt ); return 1; } if ( lseek( fd, sources.size, SEEK_SET ) < 0 ) { return -EIO; } } fuseargc = setup_argv( fuseargc, &argv ); if ( strcmp( "-dump", argv[ 1 ] ) == 0 ) { return dump_fragments( 0 ); } if ( strcmp( "-push", argv[ 1 ] ) == 0 ) { return dump_fragments( 1 ); } struct fuse_args args = FUSE_ARGS_INIT( fuseargc, argv ); struct fuse_cmdline_opts opts = { 0 }; if ( fuse_parse_cmdline( &args, &opts ) ) { return 1; } fuse_opt_free_args( &args ); return fuse_main( fuseargc, argv, &fusefile_oper, temporary? opts.mountpoint : NULL ); } fusefile-2.0/merge-overlay.8000066400000000000000000000070041470112032700160220ustar00rootroot00000000000000.mso www.tmac .TH merge-overlay 8 .SH NAME merge-overlay \- Utility to "merge down" a fusefile overlay. .SH SYNOPSIS .B merge-overlay \fIfusefile\fR \fIoverlayfile\fR .SH DESCRIPTION \fBmerge-overlay\fR is an administration utility for writing the data blocks of a fusefile overlay into a current fusefile (or ordinary file of matching size). .SH EXAMPLE This section illustrates a use of \fBmerge-overlay\fR via a use case scenario that involves a succession of steps where \fBfusefile\fR is used with successive overlays for the purpose of capturing revisions of a fused file. Notably the fusefile must be of the same size throughout the scenario, and in this example case it is a raw disk image file, \fIvm.raw\fR, for a virtual machine. .SS first day First a file \fIa\fR is set up as overlay for \fIvm.raw\fR to be \fIvmx.raw\fR for use during the day, and then the fusefile is torn down at the end of the day. .RS \fB$ fusefile \fIvmx.raw\fB -overlay:\fIa\fB \fIvm.raw\fR .RE .RS \fB$\fR ... using \fIvmx.raw\fR for the virtual machine ... .RE .RS \fB$ umount -u \fIvmx.raw\fR .RE By doing so, \fIvmx.raw\fR represents the original image file \fIvm.raw\fR initially but changes (i.e. data writes) are collated into the overlay file \fIa\fR while \fIvm.raw\fR remains unchanged. .SS second day The next day file \fIb\fR is set up as overlay stacked over \fIa\fR for \fIvm.raw\fR to again be \fIvmx.raw\fR. Then that is used over the day before the fusefile is torn down at the end of the day. .RS \fB$ fusefile \fIvmx.raw\fB -overlay:\fIa\fB:\fIb\fB \fIvm.raw\fR .RE .RS \fB$\fR ... using \fIvmx.raw\fR for the virtual machine ... .RE .RS \fB$ umount -u \fIvmx.raw\fR .RE By doing so, \fIvmx.raw\fR represents the original image file \fIvm.raw\fR including yesterday's changes collated in \fIa\fR, and any further changes are collated into the overlay file \fIb\fR while both \fIvm.raw\fR and \fIa\fR remain unchanged. .SS some days later By adding an additional overlay each day, at the end of the sixth day there is a stack of overlays, \fIa\fR:\fIb\fR:\fIc\fR:\fId\fR:\fIe\fR:\fIf\fR. Here the last overlay file \fIf\R has the last day's changes relative the overkay stack \fIa\fR:\fIb\fR:\fIc\fR:\fId\fR:\fIe\fR and so forth. One may now wish to, say, merge \fIa\fR:\fIb\fR:\fIc\fR into a single overlay file \fIA\fR, and \fId\fR:\fIe\fR:\fIf\fR into another file \fIB\fR. This could be done as follows: .RS ### First merge \fIa\fR, \fIb\fR and \fIc\fR into \fIA\fR .RE .RS \fB$ fusefile \fIvmx.raw\fB -overlay:\fIA\fB \fIvm.raw\fR .RE .RS \fB$ merge-overlay \fIvmx.raw\fB \fIa\fR .RE .RS \fB$ merge-overlay \fIvmx.raw\fB \fIb\fR .RE .RS \fB$ merge-overlay \fIvmx.raw\fB \fIc\fR .RE .RS \fB$ umount -u \fIvmx.raw\fR .RE .RS ### Second merge \fId\fE, \fIe\fR and \fIf\fR into \fIB\fR .RE .RS \fB$ fusefile \fIvmx.raw\fB -overlay:\fIA\fB:\fIB\fB \fIvm.raw\fR .RE .RS \fB$ for f in \fId\fB \fIe\fB \fIf\fB ; do merge-overlay \fIvmx.raw\fB $f ; done\fR .RE .RS \fB$ umount -u \fIvmx.raw\fR .RE Note that including \fIA\fR for the second fusefile setup is not needed for the merging but it's will be needed for using \fIvmx.raw\fR further used after the merge. .SH NOTES The fusefile overlay file contains the written data only; it does not track the order of changes but rather only keeps the last written data blocks, which also are combined into larger blocks when possible. The merging of this means to write the resulting blocks into the target file in order of byte positions. .SH SEE ALSO .B fusefile .SH COPYRIGHT Copyright 2023 Ralph Rönnquist fusefile-2.0/merge-overlay.lsp000077500000000000000000000115211470112032700164530ustar00rootroot00000000000000#!/usr/bin/newlisp ; Utility to copy from a previous overlay file onto a current ; fusefile. This would typically be done so as to "merge down" an ; overlay in an old fusefile overlay stack after having retired that ; stack. (There is an illustration example at the end of this file) ; ; Arguments: ; ; Technically this uitility merely "replays" the writes (in order of ; increasing position rather than their actual time order) that have ; been collated into an overlay file. It writes this into a file or ; fusefile that represents what the basis was when the writes ; happened. ; (die ...) - function to drop a note to stderr and exit with 1. (define (die) (write-line 2 (join (map string (args)) " ")) (exit 1)) ; (read-uint64 FD N) - function to read N consequtive unsigned long from ; file descriptor FD. Return them as a list in order (define (read-uint64 FD N) (let ((B (* N 8)) (BUFFER nil) (HEAD "") (OUT '())) ;; B = number of bytes to read ;; BUFFER = input buffer symbol ;; HEAD = prefix of bytes read but not processed ;; OUT = list of unsigned long to return ;; ;; Note that (read..) might return fewer bytes than asked for so ;; it needs a loop. (while (and (> B) (> (read FD BUFFER B))) (dec B (length BUFFER)) (extend HEAD BUFFER) (let ((I (/ (length HEAD) 8))) (when (> I) (extend OUT (unpack (dup "Lu" ) HEAD)) (setf HEAD ((* 8 I) HEAD))))) (when (> B) (die "Cannot read" N "unsigned long.")) OUT)) ; (copy-data AT SIZE) - copy the data block of SIZE bytes at position ; AT from OL.fd to FF.fd. (define (copy-data AT SIZE) ; FUSEFILE FF.fd OVERLAY OL.fd (let ((BUFFER nil) (N 0)) ;; BUFEER = transfer buffer symbol ;; N = number of bytes written upon each (write...) (when (null? (seek FF.fd AT)) (die "Cannot seek" FUSEFILE AT)) (when (null? (seek OL.fd AT)) (die "Cannot seek" OVERLAY AT)) (while (> SIZE) (when (<= (read OL.fd BUFFER SIZE)) (die "Failed reading" SIZE "bytes")) (dec SIZE (length BUFFER)) (while (and (> (length BUFFER)) (setf N (write FF.fd BUFFER (length BUFFER)))) (setf BUFFER (N BUFFER))) (when (> (length BUFFER)) (die "Failed writing" AT SIZE )) ))) ;=== Main program ; Require 2 command line arguments, afterinterpreter and script file. (when (!= (length (main-args)) 4) (die "Requires arguments: fusefile overlay")) ; Set up globals (setf FUSEFILE (main-args -2) FF.fd (if (open FUSEFILE "u") $it (die "Cannot open" FUSEFILE)) FF.end (file-info FUSEFILE 0) OVERLAY (main-args -1) OL.fd (if (open OVERLAY "r") $it (die "Cannot open" OVERLAY)) OL.end (file-info OVERLAY 0) OL.N (if (seek OL.fd FF.end) (if (read-uint64 OL.fd 1) ($it 0) (die "Cannot read" OVERLAY "table count.")) (die "Cannot seek" OVERLY "to" FF.end)) ) ; Confirm expected file size for overlay (unless (= OL.end (+ FF.end 8 (* OL.N 16))) (die OVERLAY "should be" OL.end "bytes")) ; Load the overlay table and copy data according to its entries (dolist (ENTRY (explode (if (read-uint64 OL.fd (* 2 OL.N)) $it (die "Cannot read overlay table from" OVERLAY)) 2)) ;; ENTRY = (begin end) for data block (println (format "copy %s/%d:%d" (cons OVERLAY ENTRY))) (copy-data (ENTRY 0) (- (ENTRY 1) (ENTRY 0)))) (exit 0) "dumpoverlay.lsp" ; E.g., consider a fusefile stack D:A:B:C with overlays A:B:C over D. ; That stack would have been built in a succession of first using ; stack D:A where changes are collated into overlay A, as in the ; following setup: ; ; $ fusefile E -overlay:A D ; ... writes to E (= D:A) goes into A ; $ fusermount -u E ; ; Note that the "D" part might in reality be a more complex ; composition of several file fragments, but in these examples we ; refer to it simply as "D". ; ; Continuing the example, the new stack D:A:B is used for collating ; further changes into B, as in the following setup: ; ; $ fusefile E -overlay:A:B D ; ... writes to E (= D:A:B) actually goes into B ; $ fusermount -u E ; ; Later again, the stack D:A:B:C is used for collating changes into C, ; as in the following setup: ; ; $ fusefile E -overlay:A:B:C D ; ... writes to E (= D:A:B:C) actually goes into C ; ... ; $ fusermount -u D ; ; At that point, one may decide to merge down the overlay C onto a ; D:A:B fusefile and thereby add the C changes over B. ; ; $ fusefile E -overlay:A:B D ; $ merge-overlay E C ; $ rm C ; $ fusermount -u E ; ; Or alternatively, one may decide to merge down the B changes without ; C onto a D:A fusefile and thereby add B to A. ; ; $ fusefile E -overlay:A D ; $ merge-overlay E B ; $ rm B ; $ fusermount -u E ; ; In the latter case the updated overlay A includes the writes ; collated in B and thus now the stack D:A:C would be the same as the ; previous stack D:A:B:C. ; ; End of example. fusefile-2.0/overlaytest.lsp000077500000000000000000000055121470112032700162610ustar00rootroot00000000000000#!/usr/bin/newlisp # # This is a test script for the overlay function of fusefile. # # 1) prepare a base image # 2) set up a fusefile overlay # 3) run tests # 4) dismantle the fusefile overlay # 5) remove test images ; ID is hour, minute and second values packed into a string (constant 'ID (apply string (3 3 (now))) 'BASE (format "%s.raw" ID) 'OLY (format "%s.oly" ID) 'SEGSZ 17000 'SEGN 40 ) (constant 'LIBC6 "/lib/x86_64-linux-gnu/libc.so.6" 'MINE "mine" ) (import LIBC6 "on_exit" "int" "void*" "void*") ;; Set up a fusefile (define (onexit x y) (write-line 2 (string "terminating: " x " " (get-string y))) (! (format "fusermount -u %s" BASE)) (delete-file OLY) (delete-file BASE) ) ## note: BASE is set up as a holes file with SEGN segments of size SEGSZ (! (format "dd if=/dev/zero of=%s bs=%d seek=%d count=0 status=none" BASE SEGSZ SEGN)) (unless (= (! (format "fusefile %s %s -overlay:%s %s" "-ononempty -oallow_other" BASE OLY BASE))) (exit 1)) (on_exit (callback 'onexit "void" "int" "void*") MINE) (println (list BASE OLY)) (define (die) (write-line 2 (apply string (args)))) (define (prog1 x) x) (define (pos X (OFF 0)) (+ (* SEGSZ X) OFF)) (define (read-segment FILE X (OFF 0) (N SEGSZ)) (let ((FD (open FILE "r")) (BUFFER "")) (seek FD (pos X OFF)) (prog1 (when (= N (read FD BUFFER N)) BUFFER) (close FD)))) (define (write-segment FILE X DATA (OFF 0)) (let ((FD (open FILE "u"))) (seek FD (pos X OFF)) (write FD DATA) ;(seek FD -1) (close FD))) (define (read-ulong FD) (let ((BUFFER "")) (when (= 8 (read FD BUFFER 8)) ((unpack "ld" BUFFER) 0)))) (define (read-table) (let ((AT (file-info BASE 0)) (FD (open OLY "r")) (COUNT 0) (OUT '())) (seek FD AT) (unless (setf COUNT (read-ulong FD)) (write-line 2 "** Bad count") (exit 1)) (push COUNT OUT -1) (dotimes (i COUNT) (push (list (read-ulong FD) (read-ulong FD)) OUT -1)) OUT)) (define (check-segment AT DATA (OFF 0)) (write-segment BASE AT DATA OFF) (println (format "check %2d %d: %s %s %s" AT (length DATA) (if (= (read-segment BASE AT OFF (length DATA)) DATA) "ok" "error") (if (= (read-segment OLY AT OFF (length DATA)) DATA) "ok" "error") (string (read-table)))) ) ;; Test 1 (seed (date-value)) (setf DATA (pack (dup "b" SEGSZ) (rand 256 SEGSZ)) DATB (pack (dup "b" (* 4 SEGSZ)) (rand 256 (* 4 SEGSZ))) AT (- SEGN 4)) (check-segment 0 DATA 0) (check-segment AT DATA) (check-segment (+ AT 2) DATA) (check-segment (+ AT 1) DATA) (check-segment (- AT 1) DATA -10) (check-segment (- AT 1) DATA 10) (check-segment 0 DATA 0) (check-segment 1 DATA 1) (check-segment 2 DATA 2) (check-segment 0 DATB 10) (check-segment (- SEGN 1) DATA 0) ;(setf DATA (pack (dup "b" SEGSZ) (rand 256 SEGSZ)) AT (- SEGN 4)) (exit 0)