[PATCH] mountmgr: Avoid unnecessary permission prompts on macOS 10.15 and newer.

[Brendan Shanks]

On macOS 10.15 and newer, trying to open the device node of a removable
drive will trigger an "<app> would like to access files on a removable
volume" permission prompt, even if the user doesn't have permissions
to access the device node (which is almost always the case).

Check the value of access() (recommended by Apple for this purpose)
before opening devices.
---
 dlls/mountmgr.sys/device.c  | 7 +++++++
 dlls/mountmgr.sys/diskarb.c | 4 +++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/dlls/mountmgr.sys/device.c b/dlls/mountmgr.sys/device.c
index ccb0685cedd..53ccd3c5fdc 100644
--- a/dlls/mountmgr.sys/device.c
+++ b/dlls/mountmgr.sys/device.c
@@ -26,6 +26,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <fcntl.h>
+#include <unistd.h>
 #include <sys/time.h>
 #ifdef HAVE_SYS_IOCTL_H
 # include <sys/ioctl.h>
@@ -1026,6 +1027,12 @@ static BOOL get_volume_device_info( struct volume *volume )
     if (!unix_device)
         return FALSE;
 
+    if (access( unix_device, R_OK ))
+    {
+        WARN("Unable to open %s, not accessible\n", debugstr_a(unix_device));
+        return FALSE;
+    }
+
     if (!(name = wine_get_dos_file_name( unix_device )))
     {
         ERR("Failed to convert %s to NT, err %u\n", debugstr_a(unix_device), GetLastError());
diff --git a/dlls/mountmgr.sys/diskarb.c b/dlls/mountmgr.sys/diskarb.c
index 12da89d7688..25e0745372a 100644
--- a/dlls/mountmgr.sys/diskarb.c
+++ b/dlls/mountmgr.sys/diskarb.c
@@ -25,6 +25,7 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <unistd.h>
 #ifdef HAVE_SYS_IOCTL_H
 # include <sys/ioctl.h>
 #endif
@@ -150,7 +151,8 @@ static void appeared_callback( DADiskRef disk, void *context )
     else
         if (guid_ptr) add_volume( device, device, mount_point, DEVICE_HARDDISK_VOL, guid_ptr, NULL );
 
-    if ((fd = open( device, O_RDONLY )) >= 0)
+    if (!access( device, R_OK ) &&
+        (fd = open( device, O_RDONLY )) >= 0)
     {
         dk_scsi_identify_t dsi;
 
-- 
2.26.2