From: Ralph Ronnquist Date: Sun, 2 Jul 2023 13:15:01 +0000 (+1000) Subject: Merge tag '1.0' into debian (reintroducing the sources on this branch) X-Git-Tag: debian/1.0-1 X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=926faaaa64a47215df843936eeb2a2e6142d46a2;hp=32bd05e7cd7509957497d0236f51f5f9414624d3;p=rrq%2Ffusefile.git Merge tag '1.0' into debian (reintroducing the sources on this branch) --- diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..3710bef --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + 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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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 +. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..9f02adc --- /dev/null +++ b/Makefile @@ -0,0 +1,41 @@ +BINS = fusefile + +default: $(BINS) + +ifneq (${DEBUG},) +${BINS}: CFLAGS += -DDEBUG=1 -g +endif + +${BINS}: CFLAGS += -Wall -D_FILE_OFFSET_BITS=64 +fusefile: LDFLAGS = -lfuse -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: $(INSTALLTARGETS) + +deb: + PREFIX= INCLUDE_PREFIX=/usr dpkg-buildpackage --build=full -uc -us diff --git a/README.adoc b/README.adoc new file mode 100644 index 0000000..7bf9049 --- /dev/null +++ b/README.adoc @@ -0,0 +1,29 @@ +# fusefile +:author: Ralph Ronnquist +:revdate: Sun, 30 Apr 2023 21:18:34 +1000 + +This project implements a "fuse" device to mount a concatenation of +fragments of one or more files as a single file. + +The __fused file__ allows writing to fragments (without changing their +sizes); of course only for writable fragment files. The fused file may +be set up with an __overlay file__ to capture changes instead of +writing the underlying fragment files. + +==== +This is a usage example to set up a fused file C consisting of files A +and B: +---- +$ 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. + diff --git a/fusedisk b/fusedisk new file mode 100755 index 0000000..f7df50e --- /dev/null +++ b/fusedisk @@ -0,0 +1,42 @@ +#!/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 $* diff --git a/fusefile.8 b/fusefile.8 new file mode 100644 index 0000000..6af36f4 --- /dev/null +++ b/fusefile.8 @@ -0,0 +1,226 @@ +.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 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. + +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. + +\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 . + diff --git a/fusefile.c b/fusefile.c new file mode 100644 index 0000000..5f7850b --- /dev/null +++ b/fusefile.c @@ -0,0 +1,984 @@ +/*** + 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; +}; + +struct Source { + char *filename; + ssize_t from; + ssize_t to; + ssize_t start; // starting position in concatenated file + int fd; + int dirty; +}; + +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 { + struct Source source; + struct Region *table; + size_t count; + size_t limit; +} 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 +} + +static void setup_overlay(char *filename) { + overlay.source.filename = filename; + overlay.source.fd = open( filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR ); + if ( overlay.source.fd < 0 ) { + perror( filename ); + usage(); + } +} + +#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 + 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 ( 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) ) { + int a,b; + if ( 0 ) { + } else if ( RANGE( sscanf( range, "%d:%d%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, "%d+%d%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, "%d+%n", &a, &c ), 1 )) { + p->from = ( a < 0 )? ( p->to + a ) : a; + } else if ( RANGE( sscanf( range, ":%d%n", &b, &c ), 1 )) { + p->to = ( b < 0 )? ( p->to + b ) : b; + } else if ( RANGE( sscanf( range, "%d:%n", &a, &c ), 1 )) { + p->from = ( a < 0 )? ( p->to + a ) : a; + } else if ( RANGE( sscanf( range, "%d%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) { +#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) { +#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 *fi) { +#if DEBUG + fprintf( stderr, "fusefile_open( %s, %d )\n", path, fi->flags ); + fprintf( stderr, "fixing( %d )\n", fi->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; + } +#if DEBUG + fprintf( stderr, "find_source( %ld )\n", offset ); +#endif + while ( lo + 1 < hi ) { + int m = ( lo + hi ) / 2; + if ( offset < sources.array[ m ].start ) { +#if DEBUG + fprintf( stderr, " offset < [%d].start: %ld\n", + m, sources.array[ m ].start ); +#endif + hi = m; + } else { +#if DEBUG + fprintf( stderr, " offset >= [%d].start: %ld\n", + m, sources.array[ m ].start ); +#endif + lo = m; + } + } +#if DEBUG + fprintf( stderr, "found %d\n", lo ); +#endif + 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 *fi) +{ +#if DEBUG + fprintf( stderr, "fusefile_read( %s )\n", path ); +#endif + if( strcmp( path, "/" ) != 0 ) { + return -ENOENT; + } +#if DEBUG + fprintf( stderr, "read %ld %ld\n", off, size ); +#endif + size_t rr = 0; // total reading + while ( size > 0 ) { +#if DEBUG + fprintf( stderr, " find_source %ld %ld\n", off, size ); +#endif + int i = find_source( off ); + if ( i < 0 ) { + return ( off == sources.size )? rr : -ENOENT; + } + if ( sources.array[i].fd < 0 ) { + return -ENOENT; + } +#if DEBUG + print_source( &sources.array[i] ); +#endif + 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 DEBUG + fprintf( stderr, " seek fd=%d to %ld\n", sources.array[i].fd, b ); +#endif + if ( lseek( sources.array[i].fd, b, SEEK_SET ) < 0 ) { + perror( sources.array[i].filename ); + return -ENOENT; + } +#if DEBUG + fprintf( stderr, " now read %ld from fd=%d\n", + n, sources.array[i].fd ); +#endif + ssize_t r = read( sources.array[i].fd, buf + rr, n ); +#if DEBUG + fprintf( stderr, " got %ld bytes\n", r ); +#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 *fi, + 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 ); + } +} + +/** + * 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 *fi) { +#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 *fi) +{ +#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; +} + +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 *info) { +#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 *fi) { +#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 *fi) { +#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) { +#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) { +#if DEBUG + fprintf( stderr, "fusefile_init( %d, %d )\n", fci->async_read, fci->want ); +#endif + // Disable asynchronous reading + fci->async_read = 0; + fci->want &= ~FUSE_CAP_ASYNC_READ; +#if DEBUG + fprintf( stderr, "fusefile_init( %d, %d )\n", fci->async_read, fci->want ); +#endif + return 0; +} + +#define ENDSOURCE( S ) ( S.start + ( S.to - S.from ) ) + +/** + * Dump the current fragmentation to stdout. + */ +static int dump_fragments() { + 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 + fprintf( stdout, "%s/%ld:%ld\n", + sources.array[ src ].filename, + pos - sources.array[ src ].start, + sources.array[ src ].to ); + pos = ENDSOURCE( sources.array[ src ] ); + } + if ( sources.array[ src ].start < x ) { + // Dump sources.array[src] up to x; + fprintf( stdout, "%s/%ld:%ld\n", + sources.array[ src ].filename, + pos - sources.array[ src ].start, + x - sources.array[ src ].start ); + pos = ENDSOURCE( sources.array[ src ] ); + } + if ( oly < overlay.count ) { + fprintf( stdout, "%s/%ld:%ld\n", + overlay.source.filename, + 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, + //.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", + (*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 mt; + int fg; + 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 + char *overlaytag = "-overlay:"; + int overlaytagsize = strlen( overlaytag ); + if ( strncmp( argv[i], overlaytag, overlaytagsize ) == 0 ) { + // consume "-overlay:filename" + setup_overlay( argv[i++] + overlaytagsize ); // Need a writable file + 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_load(); + } + 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(); + } + struct fuse_args args = FUSE_ARGS_INIT( fuseargc, argv ); + if ( fuse_parse_cmdline( &args, &mnt, &mt, &fg ) ) { + return 1; + } + fuse_opt_free_args( &args ); + if ( ! mnt ) { + fprintf( stderr, "missing mountpoint parameter\n" ); + return 1; + } + return fuse_main( fuseargc, argv, &fusefile_oper, temporary? mnt : NULL ); +} diff --git a/overlaytest.lsp b/overlaytest.lsp new file mode 100755 index 0000000..f9aa9ae --- /dev/null +++ b/overlaytest.lsp @@ -0,0 +1,112 @@ +#!/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)