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// This file provides functions for the wetterhorn harness that are not
// expressible directly in haskell.
//
// Currently these functions exclusively enable/disable the Haskell runtime.
#include "HsFFI.h"
#include "plugin_interface.h"
#include <unistd.h>
const char *plugin_name = "Wetterhorn";
void* foreign_interface;
void* get_foreign_interface()
{
return foreign_interface;
}
extern void performMajorGC();
void plugin_metaload(int argc, char** argv)
{
hs_init(&argc, &argv);
}
void plugin_load(int argc, char **argv, foreign_interface_t* fintf) {
hs_init(&argc, &argv);
foreign_interface = fintf;
}
void plugin_teardown(opqst_t st) {
// the opaque state should be dereferenced by now. Perform a major GC to help
// clean up before doing a reload.
//
// Used primarily in the case where the RTS is kept alive when performing a
// hot-reload.
performMajorGC();
hs_exit();
// There's a race condition between when this shared library is unloaded and
// when the haskell runtime actually exits. Don't have a good solution for
// this at the moment, so just sleep for a second.
sleep(1);
}
static const char msg[] =
"Wetterhorn Plugin v 0.01\n\n"
"Welcome, and thank you for your interest.\n\n"
"This is merely a plugin to the Wetterhorn Compositor and not meant to be\n"
"executed as a standalone binary. This plugin requires a harness to run\n"
"To use this file, please use './wtr_harness [full-path-to-wtr.so]'\n"
"That will allow you to see how this compositor works in all its glory!\n";
static const int msg_sz = sizeof(msg);
/*
* Implemens a basic _start that prints inforamtion and exits for users on an
* x86_64 system.
*/
__attribute__((naked)) void _start()
{
// Make system call to print the message
asm(
// Load the address of the string into rsi
"mov %0, %%rsi\n"
// Load the string length into edx
"mov %1, %%edx\n"
// Load the file descriptor for stdout into edi
"mov $1, %%edi\n"
// Load the syscall number for sys_write into eax
"mov $1, %%eax\n"
// Make the syscall
"syscall\n"
// Exit the program.
"mov $0, %%rdi\n"
"mov $60, %%rax\n"
"syscall\n"
:
: "r"(msg), "r"(msg_sz) // Input: address of msg
: "%rsi", "%edx", "%edi" // Clobbered registers
);
}
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