[PATCH v49 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 | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/server/fd.c b/server/fd.c
index 0b0e91ebfbb..9324dde32a9 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -1971,6 +1971,19 @@ 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)
+        {
+            if (!stat(name, &st) && S_ISSOCK(st.st_mode) && (options & FILE_DELETE_ON_CLOSE))
+                goto skip_open_fail;
+        }
+
         if (fd->unix_fd == -1)
         {
             /* check for trailing slash on file path */
@@ -1982,6 +1995,7 @@ struct fd *open_fd( struct fd *root, const char *name, struct unicode_str nt_nam
         }
     }

+skip_open_fail:
     fd->nt_name = dup_nt_name( root, nt_name, &fd->nt_namelen );
     fd->unix_name = NULL;
     if ((path = dup_fd_name( root, name )))
@@ -1993,11 +2007,12 @@ struct fd *open_fd( struct fd *root, const char *name, struct unicode_str nt_nam
     closed_fd->unix_fd = fd->unix_fd;
     closed_fd->disp_flags = 0;
     closed_fd->unix_name = fd->unix_name;
-    fstat( fd->unix_fd, &st );
+    if (fd->unix_fd != -1)
+        fstat( fd->unix_fd, &st );
     *mode = st.st_mode;

/* only bother with an inode for normal files and directories */
-    if (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode))
+    if (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode) || S_ISSOCK(st.st_mode))
     {
         unsigned int err;
         struct inode *inode = get_inode( st.st_dev, st.st_ino, fd->unix_fd );