mkcomposefs: Process last content in dumpfile without newline

I was doing some more testing and ended up crafting a dumpfile
without a trailing newline. It took me a surprising amount
of time to figure out that we just ignore data without a
trailing newline.

Hopefully, this doesn't break anyone.

Closes: containers#327
Signed-off-by: Colin Walters <[email protected]>

man/composefs-dump.md

@@ -14,7 +14,8 @@ files in it.
 
 The file format is very simple, with one file per line, first with a
 11 fixed fields, followed by a variable number of extended attributes
-for the file.
+for the file. It is recommended, but not required to include a trailing
+newline for the last file.
 
 Fields are separated by a single space, and lines by a single
 newline. Extended attributes further use '=' to separate key from

tests/assets/no-newline.dump

@@ -0,0 +1,3 @@
+/ 4096 40555 222 0 0 10 0.0 - - - trusted.foo1=bar-1 user.foo2=bar-2
+/a 0 100644 1 0 0 0 0.0 - - -
+/b 0 100644 1 0 0 0 0.0 - - -

tests/meson.build

@@ -3,6 +3,7 @@ test_assets_small = [
   'config-with-hard-link.dump.gz',
   'special.dump',
   'special_v1.dump',
+  'no-newline.dump',
 ]
 
 test_assets_small_extra = [

tools/mkcomposefs.c

@@ -643,6 +643,15 @@ static struct lcfs_node_s *tree_from_dump(FILE *input, char **out_err)
 			}
 		}
 	}
+	// Handle no trailing newline
+	if (buf.size > 0) {
+		char *err = tree_from_dump_line(&info, buf.buf, buf.size);
+		if (err != NULL) {
+			*out_err = err;
+			buffer_free(&buf);
+			return NULL;
+		}
+	}
 
 	buffer_free(&buf);