[PATCH v46 4/7] server: Allow for deletion of socket files.

[Ally Sommers]

From: Ally Sommers

Deleting the socket file is a common pattern with AF_UNIX sockets, and
is analogous to unbinding.
---
 server/fd.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/server/fd.c b/server/fd.c
index 0b0e91ebfbb..98d5ecdbcc3 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -1971,6 +1971,27 @@ struct fd *open_fd( struct fd *root, const char *name, struct unicode_str nt_nam
                 fd->unix_fd = open( name, O_RDONLY | (flags & ~(O_TRUNC | O_CREAT | O_EXCL)), *mode );
         }

+        /* POSIX requires that open(2) throws EOPNOTSUPP when `path` is a Unix
+         * socket. *BSD throws EOPNOTSUPP in this case and the additional case of
+         * O_SHLOCK or O_EXLOCK being passed when `path` resides on a filesystem
+         * without lock support.
+         *
+         * Contrary to POSIX, Linux returns ENXIO in this case, so we also check
+         * that error code here. */
+        if ((errno == EOPNOTSUPP || errno == ENXIO) &&
+            !stat( name, &st ) &&
+            S_ISSOCK(st.st_mode) &&
+            (access & DELETE))
+        {
+            if (unlink( name ))
+            {
+                file_set_error();
+                goto error;
+            }
+            else
+                fd->unix_fd = open( name, O_CREAT | O_RDWR, S_IRWXU );
+        }
+
         if (fd->unix_fd == -1)
         {
             /* check for trailing slash on file path */