/*
 *  Copyright (C) 2013-2020 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *  Copyright (C) 2009-2013 Sourcefire, Inc.
 *
 *  Authors: Tomasz Kojm, aCaB
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA 02110-1301, USA.
 */

#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_LIMITS_H
#include <sys/limits.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifndef _WIN32
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <utime.h>
#endif
#include <errno.h>
#include <dirent.h>
#include <fcntl.h>

#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif

#include "libclamav/clamav.h"
#include "shared/optparser.h"
#include "shared/output.h"
#include "shared/misc.h"
#include "shared/actions.h"
#include "shared/clamdcom.h"

#include "libclamav/str.h"
#include "libclamav/others.h"

#include "client.h"
#include "proto.h"

unsigned long int maxstream;
#ifndef _WIN32
struct sockaddr_un nixsock;
#endif
extern struct optstruct *clamdopts;

/* Inits the communication layer
 * Returns 0 if clamd is local, non zero if clamd is remote */
static int isremote(const struct optstruct *opts)
{
    int s, ret;
    const struct optstruct *opt;
    char *ipaddr, port[10];
    struct addrinfo hints, *info, *p;
    int res;

    UNUSEDPARAM(opts);

#ifndef _WIN32
    if ((opt = optget(clamdopts, "LocalSocket"))->enabled) {
        memset((void *)&nixsock, 0, sizeof(nixsock));
        nixsock.sun_family = AF_UNIX;
        strncpy(nixsock.sun_path, opt->strarg, sizeof(nixsock.sun_path));
        nixsock.sun_path[sizeof(nixsock.sun_path) - 1] = '\0';
        return 0;
    }
#endif
    if (!(opt = optget(clamdopts, "TCPSocket"))->enabled)
        return 0;

    snprintf(port, sizeof(port), "%lld", optget(clamdopts, "TCPSocket")->numarg);

    opt = optget(clamdopts, "TCPAddr");
    while (opt) {
        ipaddr = NULL;
        if (opt->strarg)
            ipaddr = (!strcmp(opt->strarg, "any") ? NULL : opt->strarg);

        memset(&hints, 0x00, sizeof(struct addrinfo));
        hints.ai_family   = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags    = AI_PASSIVE;

        if ((res = getaddrinfo(ipaddr, port, &hints, &info))) {
            logg("!Can't lookup clamd hostname: %s\n", gai_strerror(res));
            opt = opt->nextarg;
            continue;
        }

        for (p = info; p != NULL; p = p->ai_next) {
            if ((s = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) < 0) {
                logg("isremote: socket() returning: %s.\n", strerror(errno));
                continue;
            }

            switch (p->ai_family) {
                case AF_INET:
                    ((struct sockaddr_in *)(p->ai_addr))->sin_port = htons(INADDR_ANY);
                    break;
                case AF_INET6:
                    ((struct sockaddr_in6 *)(p->ai_addr))->sin6_port = htons(INADDR_ANY);
                    break;
                default:
                    break;
            }

            ret = bind(s, p->ai_addr, p->ai_addrlen);
            if (ret) {
                if (errno == EADDRINUSE) {
                    /*
                     * If we can't bind, then either we're attempting to listen on an IP that isn't
                     * ours or that clamd is already listening on.
                     */
                    closesocket(s);
                    freeaddrinfo(info);
                    return 0;
                }

                closesocket(s);
                freeaddrinfo(info);
                return 1;
            }

            closesocket(s);
        }

        freeaddrinfo(info);

        opt = opt->nextarg;
    }

    return 0;
}

/* Turns a relative path into an absolute one
 * Returns a pointer to the path (which must be
 * freed by the caller) or NULL on error */
static char *makeabs(const char *basepath)
{
    int namelen;
    char *ret;

    if (!(ret = malloc(PATH_MAX + 1))) {
        logg("^Can't make room for fullpath.\n");
        return NULL;
    }
    if (!cli_is_abspath(basepath)) {
        if (!getcwd(ret, PATH_MAX)) {
            logg("^Can't get absolute pathname of current working directory.\n");
            free(ret);
            return NULL;
        }
#ifdef _WIN32
        if (*basepath == '\\') {
            namelen = 2;
            basepath++;
        } else
#endif
            namelen = strlen(ret);
        snprintf(&ret[namelen], PATH_MAX - namelen, PATHSEP "%s", basepath);
    } else {
        strncpy(ret, basepath, PATH_MAX);
    }
    ret[PATH_MAX] = '\0';
    return ret;
}

/* Recursively scans a path with the given scantype
 * Returns non zero for serious errors, zero otherwise */
static int client_scan(const char *file, int scantype, int *infected, int *err, int maxlevel, int session, int flags)
{
    int ret;
    char *fullpath = makeabs(file);

    if (!fullpath)
        return 0;
    if (!session)
        ret = serial_client_scan(fullpath, scantype, infected, err, maxlevel, flags);
    else
        ret = parallel_client_scan(fullpath, scantype, infected, err, maxlevel, flags);
    free(fullpath);
    return ret;
}

int get_clamd_version(const struct optstruct *opts)
{
    char *buff;
    int len, sockd;
    struct RCVLN rcv;

    isremote(opts);
    if ((sockd = dconnect()) < 0) return 2;
    recvlninit(&rcv, sockd);

    if (sendln(sockd, "zVERSION", 9)) {
        closesocket(sockd);
        return 2;
    }

    while ((len = recvln(&rcv, &buff, NULL))) {
        if (len == -1) {
            logg("!Error occurred while receiving version information.\n");
            break;
        }
        printf("%s\n", buff);
    }

    closesocket(sockd);
    return 0;
}

int reload_clamd_database(const struct optstruct *opts)
{
    char *buff;
    int len, sockd;
    struct RCVLN rcv;

    isremote(opts);
    if ((sockd = dconnect()) < 0) return 2;
    recvlninit(&rcv, sockd);

    if (sendln(sockd, "zRELOAD", 8)) {
        closesocket(sockd);
        return 2;
    }

    if (!(len = recvln(&rcv, &buff, NULL)) || len < 10 || memcmp(buff, "RELOADING", 9)) {
        logg("!Clamd did not reload the database\n");
        closesocket(sockd);
        return 2;
    }
    closesocket(sockd);
    return 0;
}

int client(const struct optstruct *opts, int *infected, int *err)
{
    int remote, scantype, session = 0, errors = 0, scandash = 0, maxrec, flags = 0;
    const char *fname;

    scandash = (opts->filename && opts->filename[0] && !strcmp(opts->filename[0], "-") && !optget(opts, "file-list")->enabled && !opts->filename[1]);
    remote   = isremote(opts) | optget(opts, "stream")->enabled;
#ifdef HAVE_FD_PASSING
    if (!remote && optget(clamdopts, "LocalSocket")->enabled && (optget(opts, "fdpass")->enabled || scandash)) {
        scantype = FILDES;
        session  = optget(opts, "multiscan")->enabled;
    } else
#endif
        if (remote || scandash) {
        scantype = STREAM;
        session  = optget(opts, "multiscan")->enabled;
    } else if (optget(opts, "multiscan")->enabled)
        scantype = MULTI;
    else if (optget(opts, "allmatch")->enabled)
        scantype = ALLMATCH;
    else
        scantype = CONT;

    maxrec    = optget(clamdopts, "MaxDirectoryRecursion")->numarg;
    maxstream = optget(clamdopts, "StreamMaxLength")->numarg;
    if (optget(clamdopts, "FollowDirectorySymlinks")->enabled)
        flags |= CLI_FTW_FOLLOW_DIR_SYMLINK;
    if (optget(clamdopts, "FollowFileSymlinks")->enabled)
        flags |= CLI_FTW_FOLLOW_FILE_SYMLINK;
    flags |= CLI_FTW_TRIM_SLASHES;

    *infected = 0;

    if (scandash) {
        int sockd, ret;
        STATBUF sb;
        if (FSTAT(0, &sb) < 0) {
            logg("client.c: fstat failed for file name \"%s\", with %s\n.",
                 opts->filename[0], strerror(errno));
            return 2;
        }
        if ((sb.st_mode & S_IFMT) != S_IFREG) scantype = STREAM;
        if ((sockd = dconnect()) >= 0 && (ret = dsresult(sockd, scantype, NULL, &ret, NULL)) >= 0)
            *infected = ret;
        else
            errors = 1;
        if (sockd >= 0) closesocket(sockd);
    } else if (opts->filename || optget(opts, "file-list")->enabled) {
        if (opts->filename && optget(opts, "file-list")->enabled)
            logg("^Only scanning files from --file-list (files passed at cmdline are ignored)\n");

        while ((fname = filelist(opts, NULL))) {
            if (!strcmp(fname, "-")) {
                logg("!Scanning from standard input requires \"-\" to be the only file argument\n");
                continue;
            }
            errors += client_scan(fname, scantype, infected, err, maxrec, session, flags);
            /* this may be too strict
	    if(errors >= 10) {
		logg("!Too many errors\n");
		break;
	    }
	    */
        }
    } else {
        errors = client_scan("", scantype, infected, err, maxrec, session, flags);
    }
    return *infected ? 1 : (errors ? 2 : 0);
}
