makefs: Honor -T timestamps when creating images from mtree manifests

makefs backends rely on the fsnode structure to derive most
of the information about the underlying filesystem objects.
Depending on how the image is built, the fsnode structures
are initialized in the walk_dir or read_mtree functions.
However, read_mtree fails to take timestamps passed by -T into account,
leading to nonreproducible images in backends that do not check for -T.
Fix this and make -T backend-agnostic by adding an appropriate check
in read_mtree_keywords while making sure that mtree entries can
still override -T timestamps.

PR:		285630
Sponsored by:	Klara, Inc.
Sponsored by:	The FreeBSD Foundation
Reviewed by:	markj, emaste
Differential Revision:	https://reviews.freebsd.org/D49531

usr.sbin/makefs/makefs.8

@@ -259,9 +259,13 @@ can be a
 .Pa pathname ,
 where the timestamps are derived from that file, or an integer
 value interpreted as the number of seconds from the Epoch.
-Note that timestamps specified in an
+Timestamps in a
 .Xr mtree 5
-spec file, override the default timestamp.
+specfile (specified with
+.Fl F )
+are used even if a default timestamp is specified.
+However, the timestamps in an mtree manifest are ignored
+if a default timestamp is specified.
 .It Fl t Ar fs-type
 Create an
 .Ar fs-type

usr.sbin/makefs/makefs.c

@@ -436,6 +436,22 @@ set_option_var(const option_t *options, const char *var, const char *val,
 	return -1;
 }
 
+void
+set_tstamp(fsnode *cur)
+{
+	cur->inode->st.st_atime = stampst.st_atime;
+	cur->inode->st.st_mtime = stampst.st_mtime;
+	cur->inode->st.st_ctime = stampst.st_ctime;
+#if HAVE_STRUCT_STAT_ST_MTIMENSEC
+	cur->inode->st.st_atimensec = stampst.st_atimensec;
+	cur->inode->st.st_mtimensec = stampst.st_mtimensec;
+	cur->inode->st.st_ctimensec = stampst.st_ctimensec;
+#endif
+#if HAVE_STRUCT_STAT_BIRTHTIME
+	cur->inode->st.st_birthtime = stampst.st_birthtime;
+	cur->inode->st.st_birthtimensec = stampst.st_birthtimensec;
+#endif
+}
 
 static fstype_t *
 get_fstype(const char *type)

usr.sbin/makefs/makefs.h

@@ -188,6 +188,7 @@ fsnode *	read_mtree(const char *, fsnode *);
 int		set_option(const option_t *, const char *, char *, size_t);
 int		set_option_var(const option_t *, const char *, const char *,
     char *, size_t);
+void		set_tstamp(fsnode *);
 fsnode *	walk_dir(const char *, const char *, fsnode *, fsnode *);
 void		free_fsnodes(fsnode *);
 option_t *	copy_opts(const option_t *);

usr.sbin/makefs/mtree.c

@@ -631,6 +631,9 @@ read_mtree_keywords(FILE *fp, fsnode *node)
 				}
 				/* Ignore. */
 			} else if (strcmp(keyword, "time") == 0) {
+				/* Ignore if a default timestamp is present. */
+				if (stampst.st_ino != 0)
+					break;
 				if (value == NULL) {
 					error = ENOATTR;
 					break;
@@ -720,7 +723,9 @@ read_mtree_keywords(FILE *fp, fsnode *node)
 		return (error);
 
 	st->st_mode = (st->st_mode & ~S_IFMT) | node->type;
-
+	/* Store default timestamp, if present. */
+	if (stampst.st_ino != 0)
+		set_tstamp(node);
 	/* Nothing more to do for the global defaults. */
 	if (node->name == NULL)
 		return (0);
@@ -1051,8 +1056,16 @@ read_mtree(const char *fname, fsnode *node)
 	mtree_global.inode = &mtree_global_inode;
 	mtree_global_inode.nlink = 1;
 	mtree_global_inode.st.st_nlink = 1;
-	mtree_global_inode.st.st_atime = mtree_global_inode.st.st_ctime =
-	    mtree_global_inode.st.st_mtime = time(NULL);
+	if (stampst.st_ino != 0) {
+		set_tstamp(&mtree_global);
+	} else {
+#if HAVE_STRUCT_STAT_BIRTHTIME
+		mtree_global_inode.st.st_birthtime =
+#endif
+		    mtree_global_inode.st.st_atime =
+		    mtree_global_inode.st.st_ctime =
+		    mtree_global_inode.st.st_mtime = time(NULL);
+	}
 	errors = warnings = 0;
 
 	setgroupent(1);

usr.sbin/makefs/walk.c

@@ -248,20 +248,8 @@ create_fsnode(const char *root, const char *path, const char *name,
 	cur->type = stbuf->st_mode & S_IFMT;
 	cur->inode->nlink = 1;
 	cur->inode->st = *stbuf;
-	if (stampst.st_ino) {
-		cur->inode->st.st_atime = stampst.st_atime;
-		cur->inode->st.st_mtime = stampst.st_mtime;
-		cur->inode->st.st_ctime = stampst.st_ctime;
-#if HAVE_STRUCT_STAT_ST_MTIMENSEC
-		cur->inode->st.st_atimensec = stampst.st_atimensec;
-		cur->inode->st.st_mtimensec = stampst.st_mtimensec;
-		cur->inode->st.st_ctimensec = stampst.st_ctimensec;
-#endif
-#if HAVE_STRUCT_STAT_BIRTHTIME
-		cur->inode->st.st_birthtime = stampst.st_birthtime;
-		cur->inode->st.st_birthtimensec = stampst.st_birthtimensec;
-#endif
-	}
+	if (stampst.st_ino != 0)
+		set_tstamp(cur);
 	return (cur);
 }