su: add option to wait for shell exit code

The '-W' option causes su to wait for the elevated shell to
terminate and returns its exit code.

Costs 144 bytes.

1 files changed, 27 insertions, 3 deletions

diff --git a/loginutils/suw32.c b/loginutils/suw32.c
index 34cb175ab..b0fb26442 100644
--- a/loginutils/suw32.c
+++ b/loginutils/suw32.c
@@ -16,23 +16,32 @@
 //kbuild:lib-$(CONFIG_SUW32) += suw32.o
 
 //usage:#define suw32_trivial_usage
-//usage:       "[-c 'CMD'] [root [FILE ARGS | ARG0 ARGS]]"
+//usage:       "[-W] [root]\n"
+//usage:       "or:    su [-W] -c CMD_STRING [[--] root [ARG0 [ARG...]]\n"
+//usage:       "or:    su [-W] [--] root [arbitrary sh arguments]"
 //usage:#define suw32_full_usage "\n\n"
 //usage:       "Run shell with elevated privileges\n"
 //usage:     "\n    -c CMD  Command to pass to 'sh -c'"
+//usage:     "\n    -W      Wait for shell exit code"
 
 #include "libbb.h"
 #include "lazyload.h"
 
+enum {
+        OPT_c = (1 << 0),
+        OPT_W = (1 << 1)
+};
+
 int suw32_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int suw32_main(int argc UNUSED_PARAM, char **argv)
 {
+        unsigned opt;
         char *opt_command = NULL;
         SHELLEXECUTEINFO info;
         char *bb_path, *cwd, *q, *args;
         DECLARE_PROC_ADDR(BOOL, ShellExecuteExA, SHELLEXECUTEINFOA *);
 
-        getopt32(argv, "c:", &opt_command);
+        opt = getopt32(argv, "c:W", &opt_command);
         argv += optind;
         if (argv[0]) {
                 if (strcmp(argv[0], "root") != 0) {
@@ -48,6 +57,8 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
         memset(&info, 0, sizeof(SHELLEXECUTEINFO));
         info.cbSize = sizeof(SHELLEXECUTEINFO);
         /* info.fMask = SEE_MASK_DEFAULT; */
+        if (opt & OPT_W)
+                info.fMask |= SEE_MASK_NOCLOSEPROCESS;
         /* info.hwnd = NULL; */
         info.lpVerb = "runas";
         info.lpFile = bb_path;
@@ -87,5 +98,18 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
         if (!INIT_PROC_ADDR(shell32.dll, ShellExecuteExA))
                 return -1;
 
-        return !ShellExecuteExA(&info);
+        if (!ShellExecuteExA(&info))
+                return 1;
+
+        if (opt & OPT_W) {
+                DWORD r;
+
+                WaitForSingleObject(info.hProcess, INFINITE);
+                if (!GetExitCodeProcess(info.hProcess, &r))
+                        r = 1;
+                CloseHandle(info.hProcess);
+                return r;
+        }
+
+        return 0;
 }