From: Ralph Boehme <slow@samba.org>
Date: Thu, 14 May 2020 19:20:22 +0000 (+0200)
Subject: smbd: add fd_openat()
X-Git-Tag: ldb-2.2.0~366
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eaf1c6a338a6253068fc3e671605f18c71565dbb;p=thirdparty%2Fsamba.git

smbd: add fd_openat()

Until we actually start passing real dirfsps to fd_openat(), fd_openat()
internally calls fd_open().

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
---

diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index cbcebe71e73..a1d5f4b0c91 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -836,6 +836,70 @@ NTSTATUS fd_open(files_struct *fsp,
 	return status;
 }
 
+NTSTATUS fd_openat(files_struct *fsp,
+		   int flags,
+		   mode_t mode)
+{
+	NTSTATUS status = NT_STATUS_OK;
+	int saved_errno = 0;
+
+	if (fsp->dirfsp == fsp->conn->cwd_fsp) {
+		return fd_open(fsp, flags, mode);
+	}
+
+	/*
+	 * Never follow symlinks at this point, filename_convert() should have
+	 * resolved any symlink.
+	 */
+
+	flags |= O_NOFOLLOW;
+
+	/*
+	 * Only follow symlinks within a share
+	 * definition.
+	 */
+	fsp->fh->fd = SMB_VFS_OPENAT(fsp->conn,
+				     fsp->dirfsp,
+				     fsp->fsp_name,
+				     fsp,
+				     flags,
+				     mode);
+	if (fsp->fh->fd == -1) {
+		saved_errno = errno;
+	}
+	if (saved_errno != 0) {
+		errno = saved_errno;
+	}
+
+	if (fsp->fh->fd == -1) {
+		int posix_errno = link_errno_convert(errno);
+
+		status = map_nt_error_from_unix(posix_errno);
+
+		if (errno == EMFILE) {
+			static time_t last_warned = 0L;
+
+			if (time((time_t *) NULL) > last_warned) {
+				DEBUG(0,("Too many open files, unable "
+					"to open more!  smbd's max "
+					"open files = %d\n",
+					lp_max_open_files()));
+				last_warned = time((time_t *) NULL);
+			}
+		}
+
+		DBG_DEBUG("name %s, flags = 0%o mode = 0%o, fd = %d. %s\n",
+			  fsp_str_dbg(fsp), flags, (int)mode,
+			  fsp->fh->fd, strerror(errno));
+		return status;
+	}
+
+	DBG_DEBUG("name %s, flags = 0%o mode = 0%o, fd = %d\n",
+		  fsp_str_dbg(fsp), flags, (int)mode, fsp->fh->fd);
+
+	return status;
+}
+
 /****************************************************************************
  Close the file associated with a fsp.
 ****************************************************************************/
diff --git a/source3/smbd/proto.h b/source3/smbd/proto.h
index 3a0b25f021b..eeb6fcbf3d6 100644
--- a/source3/smbd/proto.h
+++ b/source3/smbd/proto.h
@@ -724,6 +724,9 @@ NTSTATUS check_parent_access(struct connection_struct *conn,
 				uint32_t access_mask);
 NTSTATUS fd_open(files_struct *fsp,
 		 int flags, mode_t mode);
+NTSTATUS fd_openat(files_struct *fsp,
+		   int flags,
+		   mode_t mode);
 NTSTATUS fd_close(files_struct *fsp);
 void change_file_owner_to_parent(connection_struct *conn,
 				 struct smb_filename *inherit_from_dir,