[PATCH v2] Don't require libcap-ng for virtfs support

[Peter Foley <pefoley@google.com>]

It's only required for the proxy helper.

Add a new option for the proxy helper rather than enabling it
implicitly.

Change-Id: I95b73fca625529e99d16b0a64e01c65c0c1d43f2
Signed-off-by: Peter Foley <pefoley@google.com>
---
 meson.build                   | 11 ++++++++---
 meson_options.txt             |  2 ++
 scripts/meson-buildoptions.sh |  4 ++++
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/meson.build b/meson.build
index c44d05a13f..2f9c671119 100644
--- a/meson.build
+++ b/meson.build
@@ -1759,12 +1759,17 @@ have_virtfs = get_option('virtfs') \
              error_message: 'virtio-9p (virtfs) requires Linux or macOS') \
     .require(targetos == 'linux' or cc.has_function('pthread_fchdir_np'),
              error_message: 'virtio-9p (virtfs) on macOS requires the presence of pthread_fchdir_np') \
-    .require(targetos == 'darwin' or (libattr.found() and libcap_ng.found()),
-             error_message: 'virtio-9p (virtfs) on Linux requires libcap-ng-devel and libattr-devel') \
+    .require(targetos == 'darwin' or libattr.found(),
+             error_message: 'virtio-9p (virtfs) on Linux requires libattr-devel') \
     .disable_auto_if(not have_tools and not have_system) \
     .allowed()
 
-have_virtfs_proxy_helper = targetos != 'darwin' and have_virtfs and have_tools
+have_virtfs_proxy_helper = get_option('virtfs_proxy_helper') \
+    .require(targetos != 'darwin', error_message: 'the virtfs proxy helper is incompatible with macOS') \
+    .require(have_virtfs, error_message: 'the virtfs proxy helper requires that virtfs is enabled') \
+    .disable_auto_if(not have_tools) \
+    .require(libcap_ng.found(), error_message: 'the virtfs proxy helper requires libcap-ng') \
+    .allowed()
 
 if get_option('block_drv_ro_whitelist') == ''
   config_host_data.set('CONFIG_BDRV_RO_WHITELIST', '')
diff --git a/meson_options.txt b/meson_options.txt
index 2471dd02da..908b4b7fd9 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -272,6 +272,8 @@ option('vhost_user_blk_server', type: 'feature', value: 'auto',
        description: 'build vhost-user-blk server')
 option('virtfs', type: 'feature', value: 'auto',
        description: 'virtio-9p support')
+option('virtfs_proxy_helper', type: 'feature', value: 'auto',
+       description: 'virtio-9p proxy helper support')
 option('libvduse', type: 'feature', value: 'auto',
        description: 'build VDUSE Library')
 option('vduse_blk_export', type: 'feature', value: 'auto',
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index d4369a3ad8..3bb9dd3504 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -176,6 +176,8 @@ meson_options_help() {
   printf "%s\n" '  vhost-vdpa      vhost-vdpa kernel backend support'
   printf "%s\n" '  virglrenderer   virgl rendering support'
   printf "%s\n" '  virtfs          virtio-9p support'
+  printf "%s\n" '  virtfs-proxy-helper'
+  printf "%s\n" '                  virtio-9p proxy helper support'
   printf "%s\n" '  vmnet           vmnet.framework network backend support'
   printf "%s\n" '  vnc             VNC server'
   printf "%s\n" '  vnc-jpeg        JPEG lossy compression for VNC server'
@@ -461,6 +463,8 @@ _meson_option_parse() {
     --disable-virglrenderer) printf "%s" -Dvirglrenderer=disabled ;;
     --enable-virtfs) printf "%s" -Dvirtfs=enabled ;;
     --disable-virtfs) printf "%s" -Dvirtfs=disabled ;;
+    --enable-virtfs-proxy-helper) printf "%s" -Dvirtfs_proxy_helper=enabled ;;
+    --disable-virtfs-proxy-helper) printf "%s" -Dvirtfs_proxy_helper=disabled ;;
     --enable-vmnet) printf "%s" -Dvmnet=enabled ;;
     --disable-vmnet) printf "%s" -Dvmnet=disabled ;;
     --enable-vnc) printf "%s" -Dvnc=enabled ;;
-- 
2.40.1.495.gc816e09b53d-goog