//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// dumpable.cfa -- Check if everything looks correctly set to dump core
//
// Author           : Thierry Delisle
// Created On       : Wed Jan 05 13:53:22 2022
// Last Modified By :
// Last Modified On :
// Update Count     :
//

#include <limits.h>
#include <errno.h>

#include <fstream.hfa>

extern "C" {
	#include <sys/prctl.h>
	#include <sys/resource.h>
	#include <sys/statvfs.h>
	#include <unistd.h>
}

void check_ulimit() {
	struct rlimit rlp;
	getrlimit(RLIMIT_CORE, &rlp);
	if(rlp.rlim_cur < 536870912) {
		serr | "Soft core limit is less than ~500Mb: " | rlp.rlim_cur;
	}

	if(rlp.rlim_max < 536870912) {
		serr | "Hard core limit is less than ~500Mb: " | rlp.rlim_max;
	}
}

void check_permission() {
	{
		char myExe[PATH_MAX];
		ssize_t n = readlink("/proc/self/exe", myExe, sizeof(myExe));
		if (n < 0) {
			perror("readlink(/proc/self/exe) error");
			return 1;
		}
		myExe[n] = '\0';

		if(int r = access(myExe, F_OK); r != 0) serr | "Expected current executable does not exist!" | r | errno;
		if(int r = access(myExe, R_OK); r != 0) serr | "No read access for current executable" | r | errno;
	}

	{
		char myCwd[PATH_MAX];
		if (getcwd(myCwd, sizeof(myCwd)) == 0p) {
			perror("getcwd() error");
			return;
		}

		if(access(myCwd, F_OK) != 0) serr | "Expected current working directory does not exist!";
		if(access(myCwd, R_OK) != 0) serr | "No read access for current working directory";
		if(access(myCwd, W_OK) != 0) serr | "No write access for current working directory";
	}
}

void check_free_space() {
	struct statvfs buf;
	if(statvfs(".", &buf) != 0) {
		perror("statvfs() error");
		return;
	}

	if((buf.f_bsize * buf.f_bavail) < 536870912) {
		serr | "Available diskspace is less than ~500Mb: " | (buf.f_bsize * buf.f_bavail);
	}

	if(buf.f_favail < 10) {
		serr | "Available inodes is less than 10: " | buf.f_favail;
	}

	if(buf.f_flag & ST_RDONLY) {
		serr | "Filesystem is read only";
	}
}

void check_noconflict() {
	char * name = "./core";
	if(access("./core", F_OK) == 0) serr | "A file of the core name ('" | name | "') already exists";
}

void check_dumpflag() {
	int r = prctl(PR_GET_DUMPABLE, 0, 0, 0, 0);
	if(r < 0) {
		perror("prctl(PR_GET_DUMPABLE) error");
		return;
	}

	if(r != 1) serr | "dumpable attribute not set to 1 \"(SUID_DUMP_USER, process is dumpable)\", was" | r;
}

int main() {
	check_ulimit();

	check_permission();

	check_free_space();

	check_noconflict();

	check_dumpflag();

	sout | "Done";
}