POSIX: Add invocation of klee_init_env into wrapper before calling main

To enable the POSIX support, the former implementation instrumented the
main function and inserted a call to `klee_init_env` at the beginning.

This has multiple disadvantages:
* debugging information was not correctly propagated leaving the call to
`klee_init_env` without debug information
* the main function always required `int arg, char**` as part of the
function definition of `main`

Based on the new linking infrastructure, we can now add an additional
wrapper `__klee_posix_wraper(int, char**)` that gets always called when
POSIX support is enabled. It executes `klee_init_env` and after that
calls the `main` function.

Enabling POSIX support only requires the renaming of the user provided
`main` into `__klee_posix_wrapped_main` in addition to linking.

1 files changed, 9 insertions, 0 deletions

diff --git a/runtime/POSIX/klee_init_env.c b/runtime/POSIX/klee_init_env.c
index 1fa6adea..265c3bfd 100644
--- a/runtime/POSIX/klee_init_env.c
+++ b/runtime/POSIX/klee_init_env.c
@@ -209,3 +209,12 @@ usage: (klee_init_env) [options] [program arguments]\n\
                 save_all_writes_flag, fd_fail);
 }
 
+/* The following function represents the main function of the user application
+ * and is renamed during POSIX setup */
+int __klee_posix_wrapped_main(int argc, char **argv);
+
+/* This wrapper gets called instead of main if POSIX setup is used */
+int __klee_posix_wrapper(int argcPtr, char **argvPtr) {
+  klee_init_env(&argcPtr, &argvPtr);
+  return __klee_posix_wrapped_main(argcPtr, argvPtr);
+}