[PATCH] net/slirp: Fix incorrect permissions on samba >= 2.0.5

[Niklas Hambüchen]

As the added commend and `man smb.conf` explain, starting
with that samba version, `force user` must be configured
in `[global]` in order to access the configured `smb_dir`.

This broke `-net user,smb=/path/to/folder`:

The `chdir` into e.g. `/run/user/0/qemu-smb.DCZ8Y0` failed.
In verbose logs, this manifested as:

    [..., effective(65534, 65534), real(65534, 0)] 
/source3/smbd/service.c:159(chdir_current_service)
      chdir (/run/user/0) failed, reason: Permission denied

    [..., effective(65534, 65534), real(65534, 0)] 
/source3/smbd/service.c:167(chdir_current_service)
      chdir (/run/user/0) failed, reason: Permission denied

    [..., effective(65534, 65534), real(65534, 0)] 
/source3/smbd/uid.c:448(change_to_user_internal)
      change_to_user_internal: chdir_current_service() failed!

This commit fixes it by setting the `[global]` force user to
the user that owns the directories `smbd` needs to access.

Signed-off-by: Niklas Hambüchen <mail@nh2.me>
---
 net/slirp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/slirp.c b/net/slirp.c
index be914c0be0..82387bdb19 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -850,6 +850,11 @@ static int slirp_smb(SlirpState* s, const char 
*exported_dir,
     }
     fprintf(f,
             "[global]\n"
+            "# In Samba 2.0.5 and above the 'force user' parameter\n"
+            "# also causes the primary group of the forced user to be used\n"
+            "# as the primary group for all file activity.\n"
+            "# This includes the various directories set below.\n"
+            "force user=%s\n"
             "private dir=%s\n"
             "interfaces=127.0.0.1\n"
             "bind interfaces only=yes\n"
@@ -871,6 +876,7 @@ static int slirp_smb(SlirpState* s, const char 
*exported_dir,
             "read only=no\n"
             "guest ok=yes\n"
             "force user=%s\n",
+            passwd->pw_name,
             s->smb_dir,
             s->smb_dir,
             s->smb_dir,
-- 
2.25.4