From a0ed5a7ceaf4636eab0bb66b523a9eaf437acbe8 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Tue, 2 May 2023 11:01:10 +0100
Subject: su: add option to keep console open on shell exit

The '-N' option keeps the console window open after the elevated
shell exits.

Previously this was achieved by passing the '-s' option along with
'-c'.  Recent changes allow scripts to be run without using '-c'
so a new mechanism is required.

su passes the '-N' flag to the shell.  This causes the shell to
issue a prompt and wait for user input when it exits.

Costs 200-204 bytes.
---
 shell/ash.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

(limited to 'shell')

diff --git a/shell/ash.c b/shell/ash.c
index 28f4ec47d..93c402a8b 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -238,6 +238,9 @@
 #else
 # define NUM_SCRIPTS 0
 #endif
+#if ENABLE_PLATFORM_MINGW32
+# include <conio.h>
+#endif
 
 /* So far, all bash compat is controlled by one config option */
 /* Separate defines document which part of code implements what */
@@ -540,6 +543,9 @@ struct globals_misc {
 #if ENABLE_PLATFORM_MINGW32
 	char *dirarg;  /* argument to -d option */
 	char *title;   /* argument to -t option */
+#if ENABLE_SUW32
+	int delayexit; /* set by -N option */
+# endif
 #endif
 
 	char *curdir; // = nullstr;     /* current working directory */
@@ -651,6 +657,7 @@ extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc;
 #if ENABLE_PLATFORM_MINGW32
 #define dirarg      (G_misc.dirarg     )
 #define title       (G_misc.title      )
+#define delayexit   (G_misc.delayexit  )
 #endif
 #define curdir      (G_misc.curdir     )
 #define physdir     (G_misc.physdir    )
@@ -11556,7 +11563,7 @@ evalcommand(union node *cmd, int flags)
 		 * we can just exec it.
 		 */
 #if ENABLE_PLATFORM_MINGW32
-		if (!(flags & EV_EXIT) || may_have_traps) {
+		if (!(flags & EV_EXIT) || may_have_traps IF_SUW32(|| delayexit)) {
 			/* No, forking off a child is necessary */
 			struct forkshell fs;
 
@@ -12500,6 +12507,9 @@ options(int *login_sh)
 #if ENABLE_PLATFORM_MINGW32
 		dirarg = NULL;
 		title = NULL;
+# if ENABLE_SUW32
+		delayexit = 0;
+# endif
 #endif
 	}
 	while ((p = *argptr) != NULL) {
@@ -12535,6 +12545,7 @@ options(int *login_sh)
 				/* Undocumented flags;
 				 *   -d force current directory
 				 *   -t title to display in console window
+				 *   -N prompt user before exit
 				 * Must appear before -s or -c. */
 				if (c == 'd' && val == 1) {
 					if (*argptr == NULL)
@@ -12548,6 +12559,12 @@ options(int *login_sh)
 					title = *argptr++;
 					continue;
 				}
+# if ENABLE_SUW32
+				if (c == 'N' && val == 1) {
+					delayexit = 1;
+					continue;
+				}
+# endif
 #endif
 				if (c == 's') { /* -s, +s */
 					sflag = 1;
@@ -15643,6 +15660,13 @@ exitshell(void)
 		/*free(p); - we'll exit soon */
 	}
  out:
+#if ENABLE_SUW32
+	if (delayexit) {
+		freopen("CONOUT$", "w", stdout);
+		fputs_stdout("Press any key to exit...");
+		_getch();
+	}
+#endif
 	exitreset();
 	/* dash wraps setjobctl(0) in "if (setjmp(loc.loc) == 0) {...}".
 	 * our setjobctl(0) does not panic if tcsetpgrp fails inside it.
-- 
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