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Make it be that an empty command is treated as a regular builtin

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for the purposes of any redirects it might have -- ie: as posix
requires, make the redirects appear to have been executed in a subshell
environment, so if one fails, aside from a diagnositc msg, all the
running script sees is a command that failed ($? != 0), rather
that having the shell exit which used to happen (the empty command was
being treated as a special builtin).

Continue to treat the empty command as special for the purposes of
var assigns it might contain (those are not executed in a sub-shell
and persist) - an error there (eg: assigning to a readonly var) will
continue to cause the shell (non-interactive shell) to exit.

This makes the NetBSD shell behave like all other (reasonably modern)
shells - fix method (not the implementation, details differ) taken from
FreeBSD who fixed this back in early 2010.    Problem pointed out
in (non-list) mail by Martijn Dekker.
This commit is contained in:
kre 2018-11-26 13:47:39 +00:00
parent b6daac4f83
commit d7fa5d2fb9
1 changed files with 23 additions and 6 deletions
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29
bin/sh/eval.c
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@ -1,4 +1,4 @@
/* $NetBSD: eval.c,v 1.163 2018/11/23 23:37:22 kre Exp $ */
/* $NetBSD: eval.c,v 1.164 2018/11/26 13:47:39 kre Exp $ */
/*-
* Copyright (c) 1993
@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95";
#else
__RCSID("$NetBSD: eval.c,v 1.163 2018/11/23 23:37:22 kre Exp $");
__RCSID("$NetBSD: eval.c,v 1.164 2018/11/26 13:47:39 kre Exp $");
#endif
#endif /* not lint */
@ -873,6 +873,7 @@ evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
volatile int temp_path;
const int savefuncline = funclinebase;
const int savefuncabs = funclineabs;
volatile int cmd_flags = 0;
vforked = 0;
/* First expand the arguments. */
@ -979,11 +980,16 @@ evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
/* Now locate the command. */
if (argc == 0) {
cmdentry.cmdtype = CMDSPLBLTIN;
/*
* the empty command begins as a normal builtin, and
* remains that way while redirects are processed, then
* will become special before we get to doing the
* var assigns.
*/
cmdentry.cmdtype = CMDBUILTIN;
cmdentry.u.bltin = bltincmd;
} else {
static const char PATH[] = "PATH=";
int cmd_flags = 0;
/*
* Modify the command lookup path, if a PATH= assignment
@ -1224,9 +1230,11 @@ evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
exitshell(exitstatus);
break;
case CMDBUILTIN:
case CMDSPLBLTIN:
VXTRACE(DBG_EVAL, ("builtin command%s: ",vforked?" VF":""), trargs(argv));
VTRACE(DBG_EVAL, ("special "));
case CMDBUILTIN:
VXTRACE(DBG_EVAL, ("builtin command [%d]%s: ", argc,
vforked ? " VF" : ""), trargs(argv));
mode = (cmdentry.u.bltin == execcmd) ? 0 : REDIR_PUSH;
if (flags == EV_BACKCMD) {
memout.nleft = 0;
@ -1254,6 +1262,15 @@ evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
}
redirect(cmd->ncmd.redirect, mode);
/*
* the empty command is regarded as a normal
* builtin for the purposes of redirects, but
* is a special builtin for var assigns.
* (unless we are the "command" command.)
*/
if (argc == 0 && !(cmd_flags & DO_NOFUNC))
cmdentry.cmdtype = CMDSPLBLTIN;
/* exec is a special builtin, but needs this list... */
cmdenviron = varlist.list;
/* we must check 'readonly' flag for all builtins */