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

#include <fstream.hfa>

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

	uint64_t avail = buf.f_bavail;
	avail *= buf.f_bsize;
	if ( avail < 536870912_l64u ) {
		serr | "Available diskspace is less than ~500Mb: " | avail;
	}

	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;
}

void check_core_pattern() {
	int ret;
	int cp = open("/proc/sys/kernel/core_pattern", 0, O_RDONLY );

	if ( cp < 0 ) {
		perror( "open(/proc/sys/kernel/core_pattern, O_RDONLY ) error" );
		return;
	} // if

	try {
		const char * expected = "core\n";
		const int sz = sizeof("core\n");
		char buf[512];
		ret = read( cp, buf, 512 );
		if ( ret < 0 ) {
			perror( "core pattern read error" );
			return;
		}
		ret = strncmp( expected, buf, sz - 1 );
		if ( ret != 0 ) {
			serr | "/proc/sys/kernel/core_pattern does not contain 'core', was:" | nl | nl | buf | nl
			     | "Test script expect cores files to be dumped with name 'core' in current working directory." | nl
			     | "Apport is not supported, it should be deactivated in /etc/default/apport for the test suite to work with core dumps.";
		}
	} finally {
		ret = close(cp );
		if ( ret < 0 ) perror("close(/proc/sys/kernel/core_pattern ) error");
	}
}

int main() {
	check_ulimit();
	check_permission();
	check_free_space();
	check_noconflict();
	check_dumpflag();
	check_core_pattern();
	sout | "Done";
}