From e139ae307e4fd9eb3b86a6fc2e97b4e212925199 Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Wed, 12 Apr 2017 21:02:33 +0200
Subject: [PATCH] ash: make shellexec capable of using separate argv[0] and
 filename to exec

function                                             old     new   delta
execcmd                                               71      78      +7
shellexec                                            221     224      +3
evalcommand                                         1158    1161      +3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 13/0)               Total: 13 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
 shell/ash.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/shell/ash.c b/shell/ash.c
index 983f7b108..044f166be 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -7744,9 +7744,8 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char **
  * have to change the find_command routine as well.
  * argv[-1] must exist and be writable! See tryexec() for why.
  */
-static void shellexec(char **, const char *, int) NORETURN;
-static void
-shellexec(char **argv, const char *path, int idx)
+static void shellexec(char *prog, char **argv, const char *path, int idx) NORETURN;
+static void shellexec(char *prog, char **argv, const char *path, int idx)
 {
 	char *cmdname;
 	int e;
@@ -7755,12 +7754,12 @@ shellexec(char **argv, const char *path, int idx)
 	int applet_no = -1; /* used only by FEATURE_SH_STANDALONE */
 
 	envp = listvars(VEXPORT, VUNSET, /*end:*/ NULL);
-	if (strchr(argv[0], '/') != NULL
+	if (strchr(prog, '/') != NULL
 #if ENABLE_FEATURE_SH_STANDALONE
-	 || (applet_no = find_applet_by_name(argv[0])) >= 0
+	 || (applet_no = find_applet_by_name(prog)) >= 0
 #endif
 	) {
-		tryexec(IF_FEATURE_SH_STANDALONE(applet_no,) argv[0], argv, envp);
+		tryexec(IF_FEATURE_SH_STANDALONE(applet_no,) prog, argv, envp);
 		if (applet_no >= 0) {
 			/* We tried execing ourself, but it didn't work.
 			 * Maybe /proc/self/exe doesn't exist?
@@ -7772,7 +7771,7 @@ shellexec(char **argv, const char *path, int idx)
 	} else {
  try_PATH:
 		e = ENOENT;
-		while ((cmdname = path_advance(&path, argv[0])) != NULL) {
+		while ((cmdname = path_advance(&path, prog)) != NULL) {
 			if (--idx < 0 && pathopt == NULL) {
 				tryexec(IF_FEATURE_SH_STANDALONE(-1,) cmdname, argv, envp);
 				if (errno != ENOENT && errno != ENOTDIR)
@@ -7796,8 +7795,8 @@ shellexec(char **argv, const char *path, int idx)
 	}
 	exitstatus = exerrno;
 	TRACE(("shellexec failed for %s, errno %d, suppress_int %d\n",
-		argv[0], e, suppress_int));
-	ash_msg_and_raise(EXEXIT, "%s: %s", argv[0], errmsg(e, "not found"));
+		prog, e, suppress_int));
+	ash_msg_and_raise(EXEXIT, "%s: %s", prog, errmsg(e, "not found"));
 	/* NOTREACHED */
 }
 
@@ -9371,7 +9370,7 @@ execcmd(int argc UNUSED_PARAM, char **argv)
 		/*setsignal(SIGTSTP); - unnecessary because of mflag=0 */
 		/*setsignal(SIGTTOU); - unnecessary because of mflag=0 */
 
-		shellexec(argv + 1, pathval(), 0);
+		shellexec(argv[1], argv + 1, pathval(), 0);
 		/* NOTREACHED */
 	}
 	return 0;
@@ -9773,7 +9772,7 @@ evalcommand(union node *cmd, int flags)
 			/* fall through to exec'ing external program */
 		}
 		listsetvar(varlist.list, VEXPORT|VSTACK);
-		shellexec(argv, path, cmdentry.u.index);
+		shellexec(argv[0], argv, path, cmdentry.u.index);
 		/* NOTREACHED */
 	} /* default */
 	case CMDBUILTIN: