Fixes Poly Bridge not starting on Linux when you have e.g. Google Chrome open

polybridge_fix.c

#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <dlfcn.h>

// compile: gcc polybridge_fix.c -o polybridge_fix.so -ldl -shared -fPIC
// use: set launch command in steam to
//      LD_PRELOAD=/path/to/polybridge_fix.so %command%

static FILE* (*real_fopen64)(const char *name, const char *mode);

FILE* fopen64(const char *name, const char *mode)
{
	FILE* f = real_fopen64(name, mode);
	if(f && strncmp(name, "/proc", 5) == 0 && strstr(name, "/cmdline")) {
		char tmp[32];
		fread(tmp, sizeof(tmp), 1, f);
		if(strcmp("/proc/self/exe", tmp) == 0) { // this confuses Unity3D
			fclose(f); f = real_fopen64("/dev/null", "r");
		} else {
			fseek(f, 0, SEEK_SET);
		}
	}
	return f;
}

__attribute__((constructor))
static void init() {
	real_fopen64 = (FILE* (*)()) dlsym(RTLD_NEXT, "fopen64");
	assert(real_fopen64);
}