.mso www.tmac
.TH fusefile 8
.SH NAME
-fusefile \- FUSE file mount for combining file fragments read-only
+fusefile \- FUSE file mount for combining file fragments
.SH SYNOPSIS
.B fusefile \fR[fuse options\fR] \fBmountpoint\fR \fIfilename/from-to\fR ...
.SH DESCRIPTION
-\fBfusefile\fR is FUSE file mount that presents a series of fragments of
-other files as a contiguous concatenation. It bind mounts a driver on
-top of the file mountpoint to present the nominated file fragments as
-a single, contiguous file.
+\fBfusefile\fR is FUSE file mount that presents a series of fragments
+of other files as a contiguous concatenation. It bind mounts a driver
+on top of the file mountpoint to present the nominated file fragments
+as a single, contiguous file. It accepts over-writing on the fused
+file which gets distributed accordingly to the fragments, but cannot
+change size.
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
-include all of the file.
-.TP
-\fIfilename/\fR
-include all of the file named with "/" in the pathname. This case
-requires a final "/", since the last "/" separates the filename from
-the position details.
+\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/from\fR
-include the file from the given start position, to end.
+\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/-to\fR
-include the file from beginning to the given end position (not
-included).
+\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/from-to\fR
-include the file from the given start position, up to the given end
-position (not included).
+\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
+Charater 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 EXAMPLES
Insert file "y" into file "x" at position 1200:
.RS
-\fB$ fusefile -ononempty x x/-1200 y x/1200\fR
+\fB$ fusefile -ononempty x x/:1200 y x/1200:\fR
.RE
The bind mount shadows the original file "x", and presents the
-composite instead.
+fused file instead.
-Make file y be a swap of the beginning and end of file "x", at position 2442:
+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
+\fB$ fusefile y x/2442: x/:2442\fR
.RE
.SH NOTES
-Note that \fBfusefile\fR opens the nominated source file(s) before bind
-mounting. With the fuse option \fI-ononempty\fR it will bind over an
-non-empty file, which may be useful. The source file descriptors
-remain open, but the source fragments are not recomputed. If a source
-file changes or reduces in size, anything may happen.
+Note that \fBfusefile\fR opens the nominated source file or files
+before bind mounting. With the fuse option \fI-ononempty\fR it will
+bind over an non-empty file, which may be useful. The source file
+descriptors 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,
and removes it when unmounted.
+
.SH AUTHOR
Ralph Rönnquist <ralph.ronnquist@gmail.com>
2001-2007 Miklos Szeredi <miklos@szeredi.hu>.
*/
-#define FUSE_USE_VERSION 31
+#define FUSE_USE_VERSION 33
-#include <fuse/fuse.h>
+#include <fuse.h>
#include <fuse/fuse_lowlevel.h>
#include <stdio.h>
#include <stdlib.h>
struct Source {
char *filename;
- size_t from;
- size_t to;
- size_t start; // starting position in concatenated file
+ ssize_t from;
+ ssize_t to;
+ ssize_t start; // starting position in concatenated file
int fd;
};
static struct {
struct Source *array;
int count;
- size_t size;
+ ssize_t size;
} sources;
+static struct {
+ time_t atime;
+ time_t mtime;
+ time_t ctime;
+} times;
+
#if DEBUG
static void print_source(struct Source *p) {
fprintf( stderr, "%p { %s, %ld, %ld, %ld, %d }\n",
}
#endif
-// Scan the source specification, and return the length of the
-// inclusion. "filename/from,to"
-// filename
-// filename/from
-// filename/-to
-// filename/from-to
-static size_t scan_source(char *in,struct Source *p) {
- int e = strlen( in );
- int i = e-1;
- int s = -1;
- int m = -1;
- // scan for last '/' and last '-'
- for ( ; i >= 0; i-- ) {
- if ( in[i] == '/' ) {
- s = i;
- break;
- }
- if ( in[i] == '-' ) {
- m = i;
- }
- }
- // Copy the filename, and set from and to
- p->filename = strndup( in, ( s < 0 )? e : s );
- struct stat buf;
- if ( stat( p->filename, & buf ) ) {
- perror( p->filename );
- return 1;
- }
- p->from = ( s < 0 )? 0 : atol( in+s+1 );
- if ( p->from < 0 ) {
- p->from = 0;
- }
- p->to = ( m < 0 )? buf.st_size : atol( in+m+1 );
- if ( p->from > p->to || p->to > buf.st_size ) {
- return 1;
- }
- return 0;
+static char *range;
+static unsigned int c;
+static int RANGE(int s,int n ) {
+ return ( s == n ) && *(range+c) == 0;
}
static int setup_sources(char **argv,int i,int n) {
int j = 0;
sources.size = 0;
for ( ; j < n; i++, j++ ) {
+ struct stat filestat;
struct Source *p = sources.array + j;
- if ( scan_source( argv[i], p ) ) {
- // should free everything malloc-ed
- return 1;
+ // 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 );
}
- p->start = sources.size;
- sources.size += p->to - p->from;
- 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 = 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", argv[i] );
+ 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",
+ argv[i], p->from, p->to );
return 1;
}
+ p->start = sources.size; // the fusefile position of fragment
+ sources.size += p->to - p->from;
#if DEBUG
print_source( p );
#endif
return 0;
}
-static int fusefile_getattr(const char *path, struct stat *stbuf )
-{
+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;
}
fprintf( stderr, "getattr %ld\n", sources.size );
#endif
memset( stbuf, 0, sizeof( struct stat ) );
- stbuf->st_mode = S_IFREG | 0444; // Hmmm
+ stbuf->st_mode = S_IFREG | 0644; // Hmmm
stbuf->st_nlink = 1;
stbuf->st_size = sources.size;
- time_t now = time( 0 );
- stbuf->st_atime = now;
- stbuf->st_mtime = now;
- stbuf->st_ctime = now;
+ 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_open(const char *path, struct fuse_file_info *fi)
-{
+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 ) {
+ if ( offset >= sources.size ) {
return -1;
}
- while ( lo < hi ) {
+#if DEBUG
+ fprintf( stderr, "find_source( %ld )\n", offset );
+#endif
+ while ( lo + 1 < hi ) {
int m = ( lo + hi ) / 2;
- if ( sources.array[m].start > offset ) {
+ 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 ( m+1 < hi && sources.array[m+1].start < offset ) {
- lo = m+1;
} else {
- return m;
+#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;
}
// Read <size> bytes from <offset> in file
static int fusefile_read(const char *path, char *buf, size_t size,
- off_t offset, struct fuse_file_info *fi)
+ 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", offset, size );
+ fprintf( stderr, "read %ld %ld\n", off, size );
#endif
- size_t rr = 0;
+ size_t rr = 0; // total reading
while ( size > 0 ) {
#if DEBUG
- fprintf( stderr, "find_source %ld %ld\n", offset, size );
+ fprintf( stderr, " find_source %ld %ld\n", off, size );
#endif
- int i = find_source( offset );
+ int i = find_source( off );
if ( i < 0 ) {
- return -ENOENT;
+ return ( off == sources.size )? rr : -ENOENT;
}
if ( sources.array[i].fd < 0 ) {
return -ENOENT;
#if DEBUG
print_source( &sources.array[i] );
#endif
- size_t b = offset - sources.array[i].start + sources.array[i].from;
+ 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 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, "get %ld bytes at %ld\n", n, rr );
+ 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 );
+ fprintf( stderr, " got %ld bytes\n", r );
#endif
if ( r < 0 ) {
perror( sources.array[i].filename );
break;
}
rr += r;
- offset += 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;
+}
+
+
+/**
+ * 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
+ 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 ];
+ 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;
+ }
+ }
+ 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 <off>. 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;
+ 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 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;
+ }
+ 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;
+ }
+ 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;
+}
+
static struct fuse_operations fusefile_oper = {
.getattr = fusefile_getattr,
+ .chmod = fusefile_chmod,
.open = fusefile_open,
.read = fusefile_read,
+ .poll = fusefile_poll,
+ .write = fusefile_write,
+ .write_buf = fusefile_write_buf,
.destroy = fusefile_destroy,
+ .flush = fusefile_flush,
+ .release = fusefile_release,
+ .fsync = fusefile_fsync,
+ .truncate = fusefile_truncate,
+ //.truncate = fusefile_truncate,
+ //.release = fusefile_release,
+ .init = fusefile_init,
};
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 );
}
+/**
+ * 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,
* [ <fuse options> ] <mount> <file/from-to> ...
int mt;
int fg;
int i;
+ int fuseargc;
struct stat stbuf;
int temporary = 0;
// Scan past options
break;
}
}
- if ( i > argc - 2 ) { // At least one source
+ if ( i > argc - 2 ) { // At least mount point plus one source
usage();
}
- i++;
+ fuseargc = i;
+ mnt = argv[ i++ ]; // First non-option argument is the mount pount
if ( setup_sources( argv, i, argc-i ) ) {
return 1;
}
- mnt = argv[i-1];
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;
+ }
}
- struct fuse_args args = FUSE_ARGS_INIT( i, argv );
+ fuseargc = setup_argv( fuseargc, &argv );
+ struct fuse_args args = FUSE_ARGS_INIT( fuseargc, argv );
if ( fuse_parse_cmdline( &args, &mnt, &mt, &fg ) ) {
return 1;
}
fprintf( stderr, "missing mountpoint parameter\n" );
return 1;
}
- return fuse_main( i, argv, &fusefile_oper, temporary? mnt : NULL );
+ return fuse_main( fuseargc, argv, &fusefile_oper, temporary? mnt : NULL );
}
projects / rrq / fusefile.git / commitdiff