/***
fusefile - overlay a file path with a concatenation of parts of
- other files, read only.
+ other files.
- Copyright (C) 2019 Ralph Ronnquist
+ 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
#include <unistd.h>
#include <time.h>
#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+
+struct Region {
+ off_t beg;
+ off_t end;
+};
+
+#define REGIONKEEP(r) ((r,beg == r.end)?: 0 : 1)
struct Source {
char *filename;
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;
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",
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 ) {
int j = 0;
sources.size = 0;
for ( ; j < n; i++, j++ ) {
- struct stat filestat;
struct Source *p = sources.array + j;
- // Open the fragment file rw if possible, else ro
- range = strrchr( argv[i], '/' ); // last '/'
- p->filename = range? strndup( argv[i], range - argv[i] ) : argv[i];
- 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;
- 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 = p->to + a;
- } else {
- p->to = p->from + a;
- }
- } else if ( RANGE( sscanf( range, ":%n", &c), 0 ) ) {
- // to end from start
- } else {
- fprintf( stderr, "** BAD RANGE: %s\n", argv[i] );
- return 1;
- }
- }
- if ( p->from >= p->to ||
- p->from >= filestat.st_size || p->to > filestat.st_size ) {
- fprintf( stderr, "** BAD RANGE: %s [%ld:%ld]\n",
- argv[i], p->from, p->to );
+ if ( setup_source( p, argv[i] ) ) {
return 1;
}
- p->start = sources.size; // the fusefile position of fragment
- sources.size += p->to - p->from;
#if DEBUG
print_source( p );
#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 <size> bytes from <offset> 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;
}
+ size_t rr = 0; // total reading
#if DEBUG
- fprintf( stderr, "read %ld %ld\n", off, size );
+ fprintf( stderr, "fusefile_read %ld + %ld\n", off, size );
#endif
- size_t rr = 0;
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 DEBUG
+ fprintf( stderr, " item: %d ", i );
+ print_source(& sources.array[i] );
+#endif
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 ( lseek( sources.array[i].fd, b, SEEK_SET ) < 0 ) {
perror( sources.array[i].filename );
return -ENOENT;
}
-#if DEBUG
- fprintf( stderr, "get %ld bytes at %ld\n", n, rr );
-#endif
ssize_t r = read( sources.array[i].fd, buf + rr, n );
#if DEBUG
- fprintf( stderr, "got %ld bytes\n", r );
+ fprintf( stderr, " got: %ld bytes of %ld at %ld\n", r, n, rr );
#endif
if ( r < 0 ) {
perror( sources.array[i].filename );
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;
}
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
#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 = &sources.array[ index ];
+ 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 ) {
size -= n;
off += n;
}
+ if ( source->dirty++ >= 1000 ) {
+ fsync( source->fd );
+ source->dirty = 0;
+ }
}
return 0;
}
if ( strcmp( path, "/" ) != 0 ) {
return -ENOENT;
}
-
size_t size = 0;
int i;
for ( i = 0; i < buf->count; i++ ) {
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
}
}
+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 );
if ( strcmp( path, "/" ) != 0 ) {
return -ENOENT;
}
+ fsync_all_dirty();
return 0;
}
if ( strcmp( path, "/" ) != 0 ) {
return -ENOENT;
}
+ fsync_all_dirty();
return 0;
}
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,
.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,
static void usage() {
char *usage =
"Usage: fusefile [ <fuse options> ] <mount> <file/from-to> ... \n"
-"Mounts a virtual, read-only file that is a concatenation of file fragments\n"
+"Mounts a virtual, file that is a concatenation of file fragments\n"
;
fprintf( stderr, "%s", usage );
exit( 1 );
// note: (*argv)[ argc ] is the mount point argument
char *OURS[] = {
"-odefault_permissions",
+ //"-s", // Forced single-threading
(*argv)[ argc ]
};
#define OURSN ( sizeof( OURS ) / sizeof( char* ) )
}
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 ) {
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 );
if ( fuse_parse_cmdline( &args, &mnt, &mt, &fg ) ) {
return 1;
projects / rrq / fusefile.git / blobdiff