Improve FreeBSD compatibility

First draft. Need to investigate why upstream patches include certain
function that appear to exist in FreeBSD 14.2.

libfuse/lib/cpu.cpp

@@ -1,22 +1,37 @@
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
+/*
+  ISC License
+
+  Copyright (c) 2024, Antonio SJ Musumeci <trapexit@spawn.link>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
 
 #include "cpu.hpp"
 #include "ghc/filesystem.hpp"
 #include "fmt/core.h"
 
+#include <pthread.h>
 #include <sched.h>
 
 #include <fstream>
 
 
 int
-CPU::getaffinity(const pthread_t  thread_id_,
-                 cpu_set_t       *cpuset_)
+CPU::getaffinity(cpu_set_t *cpuset_)
 {
+  const pid_t pid = 0;
   CPU_ZERO(cpuset_);
-  return sched_getaffinity(thread_id_,
+  return sched_getaffinity(pid,
                            sizeof(cpu_set_t),
                            cpuset_);
 }
@@ -70,7 +85,7 @@ CPU::count()
   int rv;
   cpu_set_t cpuset;
 
-  rv = CPU::getaffinity(0,&cpuset);
+  rv = CPU::getaffinity(&cpuset);
   if(rv < 0)
     return rv;
 
@@ -83,7 +98,7 @@ CPU::cpus()
   cpu_set_t cpuset;
   CPU::CPUVec cpuvec;
 
-  CPU::getaffinity(0,&cpuset);
+  CPU::getaffinity(&cpuset);
 
   for(int i = 0; i < CPU_SETSIZE; i++)
     {
@@ -102,7 +117,7 @@ CPU::cpu2core()
   cpu_set_t cpuset;
   CPU::CPU2CoreMap c2c;
 
-  CPU::getaffinity(0,&cpuset);
+  CPU::getaffinity(&cpuset);
 
   for(int i = 0; i < CPU_SETSIZE; i++)
     {
@@ -135,7 +150,7 @@ CPU::core2cpus()
   cpu_set_t cpuset;
   CPU::Core2CPUsMap c2c;
 
-  CPU::getaffinity(0,&cpuset);
+  CPU::getaffinity(&cpuset);
 
   for(int i = 0; i < CPU_SETSIZE; i++)
     {

libfuse/lib/cpu.hpp

@@ -1,10 +1,9 @@
 #pragma once
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include <pthread.h>
+#ifdef __FreeBSD__
+#include <pthread_np.h>
+#endif
 #include <sched.h>
 
 #include <set>
@@ -22,7 +21,7 @@ public:
 
 public:
   static int count();
-  static int getaffinity(const pthread_t thread_id, cpu_set_t *cpuset);
+  static int getaffinity(cpu_set_t *cpuset);
   static int setaffinity(const pthread_t thread_id, cpu_set_t *cpuset);
   static int setaffinity(const pthread_t thread_id, const int cpu);
   static int setaffinity(const pthread_t thread_id, const std::set<int> cpus);

mkdocs/docs/config/options.md

@@ -54,7 +54,8 @@ These options are the same regardless of whether you use them with the
   mergerfs. (default: false)
 - **lazy-umount-mountpoint=BOOL**: mergerfs will attempt to "lazy
   umount" the mountpoint before mounting itself. Useful when
-  performing live upgrades of mergerfs. (default: false)
+  performing live upgrades of mergerfs. May not work on
+  FreeBSD. (default: false)
 - **ignorepponrename=BOOL**: Ignore path preserving on
   rename. Typically rename and link act differently depending on the
   policy of `create` (read below). Enabling this will cause rename and

mkdocs/docs/faq/technical_behavior_and_limitations.md

@@ -213,3 +213,27 @@ at best, provide equivalent performance, and in some cases, worse
 performance. Splice is not supported on other platforms forcing a
 traditional read/write fallback to be provided. The splice code was
 removed to simplify the codebase.
+
+
+## How does mergerfs handle credentials?
+
+
+mergerfs is a multithreaded application in order to handle requests
+from the kernel concurrently. Each FUSE message has a header with
+certain details about the request include the process ID (pid) of the
+requestion application, the process' effective user id (uid), and
+group id (gid). To ensure proper POSIX filesystem behavior and
+security mergerfs must change its identity to match that of the
+requester when performing the core filesystem function on the
+underlying filesystem. On most Unix/POSIX based system a process and
+all its threads are under the same uid and gid. However, on Linux each
+thread may have its own credentials. This allows mergerfs to be
+multithreaded and for each thread to change to the credentials
+(seteuid,setegid) as required by the incoming message it is
+handling. However, on FreeBSD this is not possible at the moment
+(though there has been
+[discussions](https://wiki.freebsd.org/Per-Thread%20Credentials) and
+as such must change the credentials of the whole application when
+actioning messages. mergerfs does optimize this behavior by only
+changing credentials and locking the thread to do so if the process is
+currently not the same as what is necessary by the incoming request.

mkdocs/docs/related_projects.md

@@ -37,8 +37,8 @@
 
 mergerfs can be found in the
 [repositories](https://pkgs.org/download/mergerfs) of [many
-Linux](https://repology.org/project/mergerfs/versions) (and maybe
-FreeBSD) distributions.
+Linux](https://repology.org/project/mergerfs/versions) distributions
+and FreeBSD.
 
 Note: Any non-rolling release based distro is likely to have
 out-of-date versions.
@@ -51,6 +51,7 @@ out-of-date versions.
 * [Gentoo](https://packages.gentoo.org/packages/sys-fs/mergerfs)
 * [Arch (AUR)](https://aur.archlinux.org/packages/mergerfs)
 * [Void](https://voidlinux.org/packages/?arch=x86_64&q=mergerfs)
-* [NixOS](https://search.nixos.org/packages?channel=22.11&show=mergerfs&from=0&size=50&sort=relevance&type=packages&query=mergerfs)
+* [NixOS](https://search.nixos.org/packages?type=packages&query=mergerfs)
 * [Guix]()
 * [Slackware](https://slackbuilds.org/repository/15.0/system/mergerfs/?search=mergerfs)
+* [FreeBSD](https://www.freshports.org/filesystems/mergerfs)

mkdocs/docs/setup/build.md

@@ -33,9 +33,9 @@ $ su -
 # rpm -i rpmbuild/RPMS/<arch>/mergerfs-<version>.<arch>.rpm
 ```
 
-## Generic 
+## Generic Linux
 
-Have git, g++, make, python installed.
+Have git, g++ or clang, make, python installed.
 
 
 ```
@@ -44,6 +44,17 @@ $ make
 $ sudo make install
 ```
 
+## FreeBSD
+
+Have git, g++ or clang, gmake, python installed.
+
+```
+$ cd mergerfs
+$ gmake
+$ gmake install # as root
+```
+
+
 ## Build options
 
 ```

mkdocs/docs/setup/installation.md

@@ -81,6 +81,14 @@ wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs-<ver>
 sudo rpm -i mergerfs-<ver>.el<rel>.<arch>.rpm
 ```
 
+## NixOS
+
+[search.nixos.org](https://search.nixos.org/packages?channel=unstable&show=mergerfs&from=0&size=50&sort=relevance&type=packages&query=mergerfs)
+
+```
+nix-env -iA nixos.mergerfs
+```
+
 
 ## ArchLinux
 
@@ -88,10 +96,15 @@ sudo rpm -i mergerfs-<ver>.el<rel>.<arch>.rpm
 2. `pacman -S mergerfs`
 
 
-## Other
+## Other Linux Distros
 
-Static binaries are provided for situations where native packages are
-unavailable.
+[Check your distro.](../related_projects.md#distributions-including-mergerfs)
+
+
+## Static Linux Binaries
+
+If your distro does not package mergerfs there are static binaries
+provided.
 
 Get the tarball from the [releases page](https://github.com/trapexit/mergerfs/releases).
 
@@ -99,3 +112,13 @@ Get the tarball from the [releases page](https://github.com/trapexit/mergerfs/re
 wget https://github.com/trapexit/mergerfs/releases/download/<ver>/mergerfs-static-linux_<arch>.tar.gz
 sudo tar xvf mergerfs-static-linux_<arch>.tar.gz -C /
 ```
+
+
+## FreeBSD
+
+[https://www.freshports.org/filesystems/mergerfs](https://www.freshports.org/filesystems/mergerfs)
+
+
+```
+pkg install filesystems/mergerfs
+```

src/fs_readahead.cpp

@@ -25,7 +25,11 @@
 #include <fstream>
 #include <string>
 
-#include <sys/sysmacros.h>
+#ifdef __FreeBSD__
+# include <sys/types.h>
+#else
+# include <sys/sysmacros.h>
+#endif
 
 namespace l
 {

src/fs_umount2.hpp

@@ -18,8 +18,16 @@
 
 #pragma once
 
+#ifdef __FreeBSD__
+# include <sys/param.h>
+# include <sys/mount.h>
+# define umount2(target,flags) unmount(target,flags)
+# define MNT_DETACH 0
+#else
+# include <sys/mount.h>
+#endif
+
 #include <errno.h>
-#include <sys/mount.h>
 
 #include <string>
 

tools/preload.c

@@ -16,8 +16,12 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
+#ifdef __FreeBSD__
+#define O_TMPFILE 0
+#else
 #define _GNU_SOURCE
-#define _POSIX_C_SOURCE 200809L
+//#define _POSIX_C_SOURCE 200809L
+#endif
 
 #include <assert.h>
 #include <dlfcn.h>