gvfs: obviate the ssh-client requirement for gvfs

The gvfs project meson configuration attempts to locate and resolve the
path to an ssh-client on the build host, then pass that full-path to the
gvfs sftp-backend as a constant string, to be used at runtime to fork
ssh subprocesses.

As a consequence, if the build machine's ssh client path differs from
the gvfs target's path - as is common for OE/buildroot builds - gvfs can
fail at runtime. Further, build machines cannot configure gvfs without
an ssh client, even though nothing *uses* the client during the build.

The .patch in this commit has been upstreamed with gvfs, and modifies
the configuration to instead pass the string-literal `ssh` to the sftp
backend. With this change, gvfs will instead rely on PATH-expansion to
locate the user's ssh-client at runtime.

This obviates the requirement that the build machine have an ssh-client.

Signed-off-by: Alex Stewart <alex.stewart@ni.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-gnome/recipes-gnome/gvfs/gvfs/0001-daemon-PATH-expand-the-sftp-backend-ssh-client.patch

@@ -0,0 +1,60 @@
+From 8327383e262e1e7f32750a8a2d3dd708195b0f53 Mon Sep 17 00:00:00 2001
+From: Alex Stewart <alex.stewart@ni.com>
+Date: Wed, 14 Dec 2022 03:05:45 -0600
+Subject: [PATCH] daemon: PATH-expand the sftp backend ssh client
+
+Meson is currently configured to search the gvfs builder's PATH for an
+ssh client, and hardcode its fullpath as the canonical ssh client for
+the gvfs sftp backend.
+
+This setup breaks in cases where the builder has a different ssh client
+from the final runtime root, or where the client's pathes differ.
+Builders using OpenEmbedded or buildroot workspaces are particularly
+affected.
+
+Instead, set SSH_PROGRAM to `ssh` so that it gets PATH-expanded at
+runtime.
+
+Closes: https://gitlab.gnome.org/GNOME/gvfs/-/issues/465
+Signed-off-by: Alex Stewart <alex.stewart@ni.com>
+
+Upstream-Status: Accepted
+* https://gitlab.gnome.org/GNOME/gvfs/-/merge_requests/157
+  * Expect upstream merge in GNOME 44
+
+---
+ daemon/meson.build | 2 +-
+ meson.build        | 4 ----
+ 2 files changed, 1 insertion(+), 5 deletions(-)
+
+diff --git a/daemon/meson.build b/daemon/meson.build
+index e20ada29..72a16890 100644
+--- a/daemon/meson.build
++++ b/daemon/meson.build
+@@ -256,7 +256,7 @@ if enable_sftp
+     '-DDEFAULT_BACKEND_TYPE=sftp',
+     '-DBACKEND_TYPES="sftp", G_VFS_TYPE_BACKEND_SFTP,',
+     '-DMAX_JOB_THREADS=1',
+-    '-DSSH_PROGRAM="@0@"'.format(ssh.full_path()),
++    '-DSSH_PROGRAM="ssh"',
+   ]
+ 
+   programs += {'gvfsd-sftp': {'sources': sources, 'dependencies': deps, 'c_args': cflags}}
+diff --git a/meson.build b/meson.build
+index 7fd67427..a84c0104 100644
+--- a/meson.build
++++ b/meson.build
+@@ -457,10 +457,6 @@ endif
+ 
+ # *** SFTP backend ***
+ enable_sftp = get_option('sftp')
+-if enable_sftp
+-  ssh = find_program('ssh', required: false)
+-  assert(ssh.found(), 'SFTP backend requested but a ssh client is required')
+-endif
+ 
+ # *** Enable development utils ***
+ enable_devel_utils = get_option('devel_utils')
+-- 
+2.38.1
+

meta-gnome/recipes-gnome/gvfs/gvfs_1.50.2.bb

@@ -18,7 +18,10 @@ DEPENDS += "\
 
 RDEPENDS:${PN} += "gsettings-desktop-schemas"
 
-SRC_URI = "https://download.gnome.org/sources/${BPN}/${@gnome_verdir("${PV}")}/${BPN}-${PV}.tar.xz;name=archive"
+SRC_URI = "\
+    https://download.gnome.org/sources/${BPN}/${@gnome_verdir("${PV}")}/${BPN}-${PV}.tar.xz;name=archive \
+    file://0001-daemon-PATH-expand-the-sftp-backend-ssh-client.patch \
+"
 
 SRC_URI[archive.sha256sum] = "03d72b8c15ef438110f0cf457b5655266c8b515d0412b30f4d55cfa0da06ac5e"