user /keyboard: handle open()s instantly even if waiting for kb

fixes e.g. `echo */*` in dash

1 files changed, 4 insertions, 0 deletions

diff --git a/src/user/app/shell/builtins.c b/src/user/app/shell/builtins.c
index 734370b..9c294b2 100644
--- a/src/user/app/shell/builtins.c
+++ b/src/user/app/shell/builtins.c
@@ -35,6 +35,10 @@ static void cmd_cat(int argc, char **argv) {
 			if (len <= 0) break;
 			fwrite(buf, 1, len, stdout);
 		}
+		if (ferror(file)) {
+			perror(argv[i]);
+			return;
+		}
 		fclose(file);
 	}
 }