su: allow additional arguments after su -csu_cmd

The syntax becomes:

  su [-c CMD [ARG...]]

This makes it a lot easier to use values from the current shell,
instead of shell-quoting them for re-input and embedding at CMD.

Also, previously -c expected an option-argument, and now it's a flag
which requires a CMD operand, just like 'sh', so that both these
forms now error the same way (as they should):

   sh -c --
   su -c --

(previously su -c -- did not error because '--' was assumed CMD)

Adds 64 bytes.

(Based on GitHub PR #317)

1 files changed, 17 insertions, 9 deletions

diff --git a/loginutils/suw32.c b/loginutils/suw32.c
index df6d07232..46196d14c 100644
--- a/loginutils/suw32.c
+++ b/loginutils/suw32.c
@@ -16,10 +16,10 @@
 //kbuild:lib-$(CONFIG_SUW32) += suw32.o
 
 //usage:#define suw32_trivial_usage
-//usage:       "[-c \"CMD\"]"
+//usage:       "[-c \"CMD\" [ARG...]]"
 //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    -c CMD [ARG...]  Command [args] to pass to 'sh -c'"
 
 #include "libbb.h"
 #include "lazyload.h"
@@ -27,14 +27,15 @@
 int suw32_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int suw32_main(int argc UNUSED_PARAM, char **argv)
 {
-        char *opt_command = NULL;
         SHELLEXECUTEINFO info;
+        unsigned opts, c_opt;
         char *bb_path, *cwd;
         DECLARE_PROC_ADDR(BOOL, ShellExecuteExA, SHELLEXECUTEINFOA *);
 
-        getopt32(argv, "c:", &opt_command);
-        if (argv[optind])
-                bb_show_usage();
+        opts = getopt32(argv, "c");
+        c_opt = opts & 1;
+        if (!c_opt != !argv[optind])
+                bb_show_usage();  // -c without CMD, or operand without -c
 
         /* ShellExecuteEx() needs backslash as separator in UNC paths. */
         bb_path = xstrdup(bb_busybox_exec_path);
@@ -59,9 +60,16 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
         cwd = xmalloc_realpath(getcwd(NULL, 0));
         info.lpParameters =
                 xasprintf("--busybox ash -d \"%s\" -t \"BusyBox ash (Admin)\" ", cwd);
-        if (opt_command)
-                info.lpParameters =
-                        xasprintf("%s -s -c %s", info.lpParameters, quote_arg(opt_command));
+
+        if (c_opt) {
+                info.lpParameters = xappendword(info.lpParameters, "-s -c --");
+                while (argv[optind]) {
+                        char *a = quote_arg(argv[optind++]);
+                        info.lpParameters = xappendword(info.lpParameters, a);
+                        free(a);
+                }
+        }
+
         /* info.lpDirectory = NULL; */
         info.nShow = SW_SHOWNORMAL;