From 1aab211abb68b40cefb5024d0be373589c9c8f99 Mon Sep 17 00:00:00 2001
From: Daniel Wilhelm <shieldwed@outlook.com>
Date: Wed, 9 May 2018 00:07:03 +0200
Subject: 9.6

---
 zen/shell_execute.h | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

(limited to 'zen/shell_execute.h')

diff --git a/zen/shell_execute.h b/zen/shell_execute.h
index 077f18e7..18e4854b 100755
--- a/zen/shell_execute.h
+++ b/zen/shell_execute.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -9,14 +9,14 @@
 
 #include "file_error.h"
 
-    #include "thread.h"
+    #include <unistd.h> //fork()
     #include <stdlib.h> //::system()
 
 
 namespace zen
 {
 //launch commandline and report errors via popup dialog
-//windows: COM needs to be initialized before calling this function!
+//Windows: COM needs to be initialized before calling this function!
 enum ExecutionType
 {
     EXEC_TYPE_SYNC,
@@ -38,24 +38,34 @@ void shellExecute(const Zstring& command, ExecutionType type) //throw FileError
 
     if (type == EXEC_TYPE_SYNC)
     {
-        //Posix::system - execute a shell command
+        //Posix ::system() - execute a shell command
         const int rv = ::system(command.c_str()); //do NOT use std::system as its documentation says nothing about "WEXITSTATUS(rv)", ect...
-        if (rv == -1 || WEXITSTATUS(rv) == 127) //http://linux.die.net/man/3/system    "In case /bin/sh could not be executed, the exit status will be that of a command that does exit(127)"
+        if (rv == -1 || WEXITSTATUS(rv) == 127)
             throw FileError(_("Incorrect command line:") + L"\n" + utfTo<std::wstring>(command));
+        //http://linux.die.net/man/3/system    "In case /bin/sh could not be executed, the exit status will be that of a command that does exit(127)"
+        //Bonus: For an incorrect command line /bin/sh also returns with 127!
     }
     else
-	{
-		runAsync([=] { int rv = ::system(command.c_str()); (void)rv; });
-
-		warn_static("finish:")
-
-
-
-
-
-
-
-	}
+    {
+        //follow implemenation of ::system() except for waitpid():
+        const pid_t pid = ::fork();
+        if (pid < 0) //pids are never negative, empiric proof: https://linux.die.net/man/2/wait
+            THROW_LAST_FILE_ERROR(_("Incorrect command line:") + L"\n" + utfTo<std::wstring>(command), L"fork");
+
+        if (pid == 0) //child process
+        {
+            const char* argv[] = { "sh", "-c", command.c_str(), nullptr };
+            /*int rv =*/::execv("/bin/sh", const_cast<char**>(argv));
+            //safe to cast away const: http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
+            //  "The statement about argv[] and envp[] being constants is included to make explicit to future
+            //   writers of language bindings that these objects are completely constant. Due to a limitation of
+            //   the ISO C standard, it is not possible to state that idea in standard C."
+
+            //"execv() only returns if an error has occurred. The return value is -1, and errno is set to indicate the error."
+            ::_exit(127); //[!] avoid flushing I/O buffers or doing other clean up from child process like with "exit(127)"!
+        }
+        //else //parent process
+    }
 }
 }
 }
-- 
cgit