sh: Do not abort on a redirection error if there is no command word.

Although simple commands without a command word (only assignments and/or
redirections) are much like special builtins, POSIX and most shells seem to
agree that redirection errors should not abort the shell in this case. Of
course, the assignments persist and assignment errors are fatal.

To get the old behaviour portably, use the ':' special builtin.
To get the new behaviour portably, given that there are no assignments, use
the 'true' regular builtin.

1 files changed, 7 insertions, 1 deletions

diff --git a/bin/sh/eval.c b/bin/sh/eval.c
index cdd6386..199ec1e 100644
--- a/bin/sh/eval.c
+++ b/bin/sh/eval.c
@@ -680,7 +680,7 @@ evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 		/* Variable assignment(s) without command */
 		cmdentry.cmdtype = CMDBUILTIN;
 		cmdentry.u.index = BLTINCMD;
-		cmdentry.special = 1;
+		cmdentry.special = 0;
 	} else {
 		static const char PATH[] = "PATH=";
 		int cmd_flags = 0, bltinonly = 0;
@@ -891,6 +891,12 @@ evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 		}
 		handler = &jmploc;
 		redirect(cmd->ncmd.redirect, mode);
+		/*
+		 * If there is no command word, redirection errors should
+		 * not be fatal but assignment errors should.
+		 */
+		if (argc == 0 && !(flags & EV_BACKCMD))
+			cmdentry.special = 1;
 		if (cmdentry.special)
 			listsetvar(cmdenviron);
 		commandname = argv[0];