Move safe open code out of sudo_edit.c and into edit_open.c.

src/sudo_edit.h

@@ -0,0 +1,53 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2021 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef SUDO_EDIT_H
+#define SUDO_EDIT_H
+
+/*
+ * Directory open flags for use with openat(2).
+ * Use O_SEARCH/O_PATH and/or O_DIRECTORY where possible.
+ */
+#if defined(O_SEARCH)
+# if defined(O_DIRECTORY)
+#  define DIR_OPEN_FLAGS	(O_SEARCH|O_DIRECTORY)
+# else
+#  define DIR_OPEN_FLAGS	(O_SEARCH)
+# endif
+#elif defined(O_PATH)
+# if defined(O_DIRECTORY)
+#  define DIR_OPEN_FLAGS	(O_PATH|O_DIRECTORY)
+# else
+#  define DIR_OPEN_FLAGS	(O_PATH)
+# endif
+#elif defined(O_DIRECTORY)
+# define DIR_OPEN_FLAGS		(O_RDONLY|O_DIRECTORY)
+#else
+# define DIR_OPEN_FLAGS		(O_RDONLY|O_NONBLOCK)
+#endif
+
+/* copy_file.c */
+int sudo_copy_file(const char *src, int src_fd, off_t src_len, const char *dst, int dst_fd, off_t dst_len);
+bool sudo_check_temp_file(int tfd, const char *tname, uid_t uid, struct stat *sb);
+
+/* edit_open.c */
+void switch_user(uid_t euid, gid_t egid, int ngroups, GETGROUPS_T *groups);
+int sudo_edit_open(char *path, int oflags, mode_t mode, struct user_details *ud, struct command_details *cd);
+int dir_is_writable(int dfd, struct user_details *ud, struct command_details *cd);
+
+#endif /* SUDO_EDIT_H */