[PATCH] ash: simplify handling of local PATH assignment

[Ron Yorston]

dash commit cbb71a8 'eval: Add assignment built-in support again'
is large and intrusive.  It hasn't (yet) been imported into BusyBox
ash.

One element of this patch is useful in its own right: a simplification
of the treatment of local assignments to PATH.

function                                             old     new   delta
evalcommand                                         1724    1684     -40
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-40)             Total: -40 bytes

Signed-off-by: Ron Yorston <rmy at pobox.com>
---
 shell/ash.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/shell/ash.c b/shell/ash.c
index a01c8fa8b..e6ce67ed2 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -10004,6 +10004,10 @@ evalcommand(union node *cmd, int flags)
 	arglist.lastp = &arglist.list;
 	*arglist.lastp = NULL;
 
+	cmd_is_exec = 0;
+	spclbltin = -1;
+	path = NULL;
+
 	argc = 0;
 	if (cmd->ncmd.args) {
 		struct builtincmd *bcmd;
@@ -10053,23 +10057,13 @@ evalcommand(union node *cmd, int flags)
 	}
 	status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);
 
-	path = vpath.var_text;
 	for (argp = cmd->ncmd.assign; argp; argp = argp->narg.next) {
 		struct strlist **spp;
-		char *p;
 
 		spp = varlist.lastp;
 		expandarg(argp, &varlist, EXP_VARTILDE);
 
 		mklocal((*spp)->text);
-
-		/*
-		 * Modify the command lookup path, if a PATH= assignment
-		 * is present
-		 */
-		p = (*spp)->text;
-		if (varcmp(p, path) == 0)
-			path = p;
 	}
 
 	/* Print the command if xflag is set. */
@@ -10108,18 +10102,11 @@ evalcommand(union node *cmd, int flags)
 		safe_write(preverrout_fd, "\n", 1);
 	}
 
-	cmd_is_exec = 0;
-	spclbltin = -1;
-
 	/* Now locate the command. */
 	if (argc) {
 		int cmd_flag = DO_ERR;
-#if ENABLE_ASH_CMDCMD
-		const char *oldpath = path + 5;
-#endif
-		path += 5;
 		for (;;) {
-			find_command(argv[0], &cmdentry, cmd_flag, path);
+			find_command(argv[0], &cmdentry, cmd_flag, path ? path : pathval());
 			if (cmdentry.cmdtype == CMDUNKNOWN) {
 				flush_stdout_stderr();
 				status = 127;
@@ -10135,7 +10122,6 @@ evalcommand(union node *cmd, int flags)
 				cmd_is_exec = 1;
 #if ENABLE_ASH_CMDCMD
 			if (cmdentry.u.cmd == COMMANDCMD) {
-				path = oldpath;
 				nargv = parse_command_args(argv, &path);
 				if (!nargv)
 					break;
@@ -10226,6 +10212,7 @@ evalcommand(union node *cmd, int flags)
 			/* fall through to exec'ing external program */
 		}
 		listsetvar(varlist.list, VEXPORT|VSTACK);
+		path = path ? path : pathval();
 		shellexec(argv[0], argv, path, cmdentry.u.index);
 		/* NOTREACHED */
 	} /* default */
-- 
2.19.2