Remove macOS support

OSXFUSE is no longer open source, see e.g.
https://colatkinson.site/macos/fuse/2019/09/29/osxfuse/

It looks like Apple is killing the whole category:
https://news.ycombinator.com/item?id=22251076

I will not personally put uncompensated effort into supporting
non-open source environments, especially ones that are this hostile to
work with. The macOS kludges were a significant amount of code, about
25% of the remaining non-test lines, and the primary source of
complexity and alternate code paths.

The API definitions will be remain for a short while, with deprecation
markers. This should let multiplatform callers work without changes.
Everything deprecated will be removed soon, so please adjust
your code.

Fixes #224

doc/mount-linux-error-init.seq → doc/mount-error-init.seq

@@ -17,16 +17,22 @@ seqdiag {
   fusermount -> kernel [label="mount(2)"];
   kernel ->> mounts [label="mount is visible"];
   fusermount <-- kernel [label="mount(2) returns"];
-  fuse <<-- fusermount [diagonal, label="exit, receive /dev/fuse fd", leftnote="on Linux, successful exit here\nmeans the mount has happened,\nthough InitRequest might not have yet"];
-  app <-- fuse [label="Mount returns\nConn.Ready is already closed"];
+  fuse <<-- fusermount [diagonal, label="exit, receive /dev/fuse fd"];
 
-  app -> fuse [label="fs.Serve"];
-  fuse => kernel [label="read /dev/fuse fd", note="starts with InitRequest"];
-  fuse -> app [label="Init"];
-  fuse <-- app [color=red];
+  fuse => kernel [label="read /dev/fuse fd: InitRequest"];
   fuse -> kernel [label="write /dev/fuse fd", color=red];
   kernel -> kernel [label="set connection\nstate to error", color=red];
   fuse <-- kernel;
-  ... conn.MountError == nil, so it is still mounted ...
-  ... call conn.Close to clean up ...
+
+  ... Mount calls Unmount to clean up ...
+  fuse -> fusermount [label="fusermount -u"];
+  fusermount -> kernel;
+  kernel <<-- mounts;
+  fusermount <-- kernel;
+  fuse <<-- fusermount [diagonal];
+
+  fuse => kernel  [label="close /dev/fuse fd"];
+  fuse <<-- kernel [diagonal, label="/dev/fuse is released"];
+
+  app <-- fuse [label="Mount returns", color=red];
 }

doc/mount-sequence.md

@@ -7,24 +7,14 @@ more complex API on us.
 
 ## Successful runs
 
-On Linux, the mount is immediate and file system accesses wait until
-the requests are served.
+The mount is immediate and file system accesses wait until the requests are served.
 
-![Diagram of Linux FUSE mount sequence](mount-linux.seq.png)
-
-On OS X, the mount becomes visible only after `InitRequest` (and maybe
-more) have been served.
-
-![Diagram of OSXFUSE mount sequence](mount-osx.seq.png)
+![Diagram of the mount sequence](mount.seq.png)
 
 
 ## Errors
 
-Let's see what happens if `InitRequest` gets an error response. On
-Linux, the mountpoint is there but all operations will fail:
-
-![Diagram of Linux error handling](mount-linux-error-init.seq.png)
-
-On OS X, the mount never happened:
+Let's see what happens if `InitRequest` gets an error response.
+The mountpoint is temporarily there but all operations will fail:
 
-![Diagram of OS X error handling](mount-osx-error-init.seq.png)
+![Diagram of error handling](mount-error-init.seq.png)

doc/mount-linux.seq → doc/mount.seq

@@ -1,5 +1,5 @@
 seqdiag {
-  // seqdiag -T svg -o doc/mount-osx.svg doc/mount-osx.seq
+  // seqdiag -T svg -o doc/mount.svg doc/mount.seq
   app;
   fuse [label="bazil.org/fuse"];
   fusermount;
@@ -12,16 +12,21 @@ seqdiag {
   fusermount -> kernel [label="mount(2)"];
   kernel ->> mounts [label="mount is visible"];
   fusermount <-- kernel [label="mount(2) returns"];
-  fuse <<-- fusermount [diagonal, label="exit, receive /dev/fuse fd", leftnote="on Linux, successful exit here\nmeans the mount has happened,\nthough InitRequest might not have yet"];
-  app <-- fuse [label="Mount returns\nConn.Ready is already closed", rightnote="InitRequest and StatfsRequest\nmay or may not be seen\nbefore Conn.Ready,\ndepending on platform"];
+  fuse <<-- fusermount [diagonal, label="exit, receive /dev/fuse fd"];
+
+  fuse => kernel [label="read /dev/fuse fd: InitRequest"];
+  fuse => kernel [label="write /dev/fuse fd: InitResponse"];
+
+  app <-- fuse [label="Mount returns"];
 
   app -> fuse [label="fs.Serve"];
-  fuse => kernel [label="read /dev/fuse fd", note="starts with InitRequest"];
+  fuse => kernel [label="read /dev/fuse fd"];
   fuse => app [label="FS/Node/Handle methods"];
   fuse => kernel [label="write /dev/fuse fd"];
   ... repeat ...
 
   ... shutting down ...
+  fuse -> kernel [label="read /dev/fuse fd"];
   app -> fuse [label="Unmount"];
   fuse -> fusermount [label="fusermount -u"];
   fusermount -> kernel;
@@ -31,11 +36,11 @@ seqdiag {
   app <-- fuse [label="Unmount returns"];
 
   // actually triggers before above
-  fuse <<-- kernel [diagonal, label="/dev/fuse EOF"];
+  fuse <-- kernel [diagonal, label="/dev/fuse EOF"];
   app <-- fuse [label="fs.Serve returns"];
 
   app -> fuse [label="conn.Close"];
-  fuse -> kernel  [label="close /dev/fuse fd"];
-  fuse <-- kernel;
+  fuse => kernel  [label="close /dev/fuse fd"];
+  fuse <<-- kernel [diagonal, label="/dev/fuse is released"];
   app <-- fuse;
 }

error_std.go

@@ -4,17 +4,16 @@ package fuse
 // across platforms.
 //
 // getxattr return value for "extended attribute does not exist" is
-// ENOATTR on OS X, and ENODATA on Linux and apparently at least
-// NetBSD. There may be a #define ENOATTR on Linux too, but the value
-// is ENODATA in the actual syscalls. FreeBSD and OpenBSD have no
-// ENODATA, only ENOATTR. ENOATTR is not in any of the standards,
-// ENODATA exists but is only used for STREAMs.
+// ENODATA on Linux and apparently at least NetBSD. There may be a
+// #define ENOATTR on Linux too, but the value is ENODATA in the
+// actual syscalls. FreeBSD and OpenBSD have no ENODATA, only ENOATTR.
+// ENOATTR is not in any of the standards, ENODATA exists but is only
+// used for STREAMs.
 //
 // Each platform will define it a errNoXattr constant, and this file
 // will enforce that it implements the right interfaces and hide the
 // implementation.
 //
-// https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man2/getxattr.2.html
 // http://mail-index.netbsd.org/tech-kern/2012/04/30/msg013090.html
 // http://mail-index.netbsd.org/tech-kern/2012/04/30/msg013097.html
 // http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html

examples/clockfs/clockfs.go

@@ -29,8 +29,6 @@ func run(mountpoint string) error {
 		mountpoint,
 		fuse.FSName("clock"),
 		fuse.Subtype("clockfsfs"),
-		fuse.LocalVolume(),
-		fuse.VolumeName("Clock filesystem"),
 	)
 	if err != nil {
 		return err
@@ -58,12 +56,6 @@ func run(mountpoint string) error {
 	if err := srv.Serve(filesys); err != nil {
 		return err
 	}
-
-	// Check if the mount process has an error to report.
-	<-c.Ready
-	if err := c.MountError; err != nil {
-		return err
-	}
 	return nil
 }
 

examples/hellofs/hello.go

@@ -34,8 +34,6 @@ func main() {
 		mountpoint,
 		fuse.FSName("helloworld"),
 		fuse.Subtype("hellofs"),
-		fuse.LocalVolume(),
-		fuse.VolumeName("Hello world!"),
 	)
 	if err != nil {
 		log.Fatal(err)
@@ -46,12 +44,6 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-
-	// check if the mount process has an error to report
-	<-c.Ready
-	if err := c.MountError; err != nil {
-		log.Fatal(err)
-	}
 }
 
 // FS implements the hello world file system.

fs/fstestutil/mounted.go

@@ -1,7 +1,6 @@
 package fstestutil
 
 import (
-	"errors"
 	"io/ioutil"
 	"log"
 	"os"
@@ -67,9 +66,6 @@ func (mnt *Mount) Close() {
 // filesystem used is constructed by calling a function, to allow
 // storing fuse.Conn and fs.Server in the FS.
 //
-// It also waits until the filesystem is known to be visible (OS X
-// workaround).
-//
 // After successful return, caller must clean up by calling Close.
 func MountedFunc(fn func(*Mount) fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
 	dir, err := ioutil.TempDir("", "fusetest")
@@ -96,27 +92,11 @@ func MountedFunc(fn func(*Mount) fs.FS, conf *fs.Config, options ...fuse.MountOp
 		serveErr <- server.Serve(filesys)
 	}()
 
-	select {
-	case <-mnt.Conn.Ready:
-		if err := mnt.Conn.MountError; err != nil {
-			return nil, err
-		}
-		return mnt, nil
-	case err = <-mnt.Error:
-		// Serve quit early
-		if err != nil {
-			return nil, err
-		}
-		//lint:ignore ST1005 uppercase because it's an idenfier
-		return nil, errors.New("Serve exited early")
-	}
+	return mnt, nil
 }
 
 // Mounted mounts the fuse.Server at a temporary directory.
 //
-// It also waits until the filesystem is known to be visible (OS X
-// workaround).
-//
 // After successful return, caller must clean up by calling Close.
 func Mounted(filesys fs.FS, conf *fs.Config, options ...fuse.MountOption) (*Mount, error) {
 	fn := func(*Mount) fs.FS { return filesys }

fs/fstestutil/mountinfo_linux.go

@@ -27,8 +27,7 @@ var fstabUnescape = strings.NewReplacer(
 var errNotFound = errors.New("mount not found")
 
 func getMountInfo(mnt string) (*MountInfo, error) {
-	// TODO delay a little to minimize an undiagnosed race between
-	// fuse.Conn.Ready and /proc/mounts
+	// TODO delay a little to minimize an undiagnosed race
 	// https://github.com/bazil/fuse/issues/228
 	time.Sleep(10 * time.Millisecond)
 	data, err := ioutil.ReadFile("/proc/mounts")