[git commit] ash: implement "exec -a ARGV0 CMD ARGV1..."

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=6c149f4d9afaed9edb75c88b784ad900c1f40700
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
execcmd                                               71     112     +41
shellexec                                            221     224      +3
evalcommand                                         1158    1161      +3
localcmd                                             364     366      +2
unaliascmd                                           163     154      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 49/-9)              Total: 40 bytes

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 shell/ash.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/shell/ash.c b/shell/ash.c
index 044f166..e170bec 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -3345,11 +3345,9 @@ unaliascmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
 	int i;
 
-	while ((i = nextopt("a")) != '\0') {
-		if (i == 'a') {
-			rmaliases();
-			return 0;
-		}
+	while (nextopt("a") != '\0') {
+		rmaliases();
+		return 0;
 	}
 	for (i = 0; *argptr; argptr++) {
 		if (unalias(*argptr)) {
@@ -9354,7 +9352,14 @@ truecmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 static int FAST_FUNC
 execcmd(int argc UNUSED_PARAM, char **argv)
 {
-	if (argv[1]) {
+	optionarg = NULL;
+	while (nextopt("a:") != '\0')
+		/* nextopt() sets optionarg to "-a ARGV0" */;
+
+	argv = argptr;
+	if (argv[0]) {
+		char *prog;
+
 		iflag = 0;              /* exit on error */
 		mflag = 0;
 		optschanged();
@@ -9370,7 +9375,10 @@ execcmd(int argc UNUSED_PARAM, char **argv)
 		/*setsignal(SIGTSTP); - unnecessary because of mflag=0 */
 		/*setsignal(SIGTTOU); - unnecessary because of mflag=0 */
 
-		shellexec(argv[1], argv + 1, pathval(), 0);
+		prog = argv[0];
+		if (optionarg)
+			argv[0] = optionarg;
+		shellexec(prog, argv, pathval(), 0);
 		/* NOTREACHED */
 	}
 	return 0;