drop: search PATH for cmd.exe/PowerShell

Rather than hardcode the paths of cmd.exe and PowerShell find them
by searching PATH.

Saves 104-128 bytes.

(GitHub issue #240)

1 files changed, 25 insertions, 27 deletions

diff --git a/miscutils/drop.c b/miscutils/drop.c
index f73125e1b..9ebee3f04 100644
--- a/miscutils/drop.c
+++ b/miscutils/drop.c
@@ -60,7 +60,6 @@
 int drop_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int drop_main(int argc, char **argv)
 {
-        const char *exe;
         SAFER_LEVEL_HANDLE safer;
         HANDLE token;
         STARTUPINFO si;
@@ -72,7 +71,6 @@ int drop_main(int argc, char **argv)
                 0x00, 0x00, 0x00, 0x10,
                 0x00, 0x20, 0x00, 0x00
         };
-        char *cmd, *q, *newcmd, **a;
         DWORD code;
         // This shouldn't be necessary but without it the binary complains
         // it can't find CreateProcessAsUserA on older versions of Windows.
@@ -97,55 +95,55 @@ int drop_main(int argc, char **argv)
                 TIL.Label.Attributes = SE_GROUP_INTEGRITY;
                 if (SetTokenInformation(token, TokenIntegrityLevel, &TIL,
                                                 sizeof(TOKEN_MANDATORY_LABEL))) {
-                        int skip = 1;
+                        char **a = argv + 1;
+                        const char *arg;
+                        char *exe, *cmd;
 
                         if (argc == 1 || strcmp(argv[1], "-c") == 0
                                                 IF_CDROP(|| strcmp(argv[1], "/c") == 0)) {
 #if ENABLE_PDROP
                                 if (*applet_name == 'p') {
-                                        exe = "C:/Windows/System32/WindowsPowerShell/v1.0/powershell.exe";
-                                        cmd = xstrdup("powershell");
+                                        arg = "powershell.exe";
+                                        exe = find_first_executable(arg);
                                 } else
 #endif
 #if ENABLE_CDROP
                                 if (*applet_name == 'c') {
-                                        exe = "C:/Windows/System32/cmd.exe";
-                                        cmd = xstrdup("cmd");
+                                        arg = "cmd.exe";
+                                        exe = find_first_executable(arg);
                                 } else
 #endif
                                 {
-                                        exe = bb_busybox_exec_path;
-                                        cmd = xstrdup("sh");
+                                        arg = "sh";
+                                        exe = xstrdup(bb_busybox_exec_path);
                                 }
-                                skip = 0;
                         } else {
-                                char *file;
+                                arg = *a++;
 
 #if ENABLE_FEATURE_PREFER_APPLETS
-                                if (!has_path(argv[1]) && find_applet_by_name(argv[1]) >= 0) {
-                                        file = xstrdup(bb_busybox_exec_path);
+                                if (!has_path(arg) && find_applet_by_name(arg) >= 0) {
+                                        exe = xstrdup(bb_busybox_exec_path);
                                 } else
 #endif
-                                if (has_path(argv[1])) {
-                                        file = file_is_win32_exe(argv[1]);
+                                if (has_path(arg)) {
+                                        exe = file_is_win32_exe(arg);
                                 } else {
-                                        file = find_first_executable(argv[1]);
-                                }
-
-                                if (file == NULL) {
-                                        xfunc_error_retval = 127;
-                                        bb_error_msg_and_die("can't find '%s'", argv[1]);
+                                        exe = find_first_executable(arg);
                                 }
+                        }
 
-                                slash_to_bs(file);
-                                exe = file;
-                                cmd = quote_arg(argv[1]);
+                        if (exe == NULL) {
+                                xfunc_error_retval = 127;
+                                bb_error_msg_and_die("can't find '%s'", arg);
                         }
 
+                        slash_to_bs(exe);
+                        cmd = quote_arg(arg);
+
                         // Build the command line
-                        for (a = argv + 1 + skip; *a; ++a) {
-                                q = quote_arg(*a);
-                                newcmd = xasprintf("%s %s", cmd, q);
+                        while (*a) {
+                                char *q = quote_arg(*a++);
+                                char *newcmd = xasprintf("%s %s", cmd, q);
                                 free(q);
                                 free(cmd);
                                 cmd = newcmd;