//
// based on source code from http://www.ols.es/exim/dlext/ by David Saez <david@ols.es>,
// source code of exim by Philip Hazel <ph10@cam.ac.uk>
// and source code of exiscan by Tom Kistner <tom@duncanthrax.net>
//
//	warn	set acl_m0	= ${dlfunc{/usr/local/libexec/exim/exim-dlfunc.so}{spamd}\
//				{127.0.0.1 783}{defer_ok}{spamd}{report}}
//

//#include "local_scan.h"
//#include "macros.h"
#include "exim.h"

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdarg.h>
#include <errno.h>

#define SPAMD_TIMEOUT		120

#define SPAM_COMMAND_REPORT	1
#define SPAM_COMMAND_PROCESS	2

extern uschar *tod_stamp(int);

//-------------------------------------------------------------------------

int spamd(uschar **yield, int argc, uschar *argv[]) {
    char	*arg_socket_addr;
    char	*arg_defer_ok;
    char	*arg_user_name;
    char	*arg_spamd_command;
    int		defer_ok;
    int		spamd_command;
    char	tcp_addr[15];
    int		tcp_port;
    FILE	*mbox_file = NULL;
    unsigned long mbox_size;
    uschar	*s, *p;
    header_line *my_header, *header_new, *header_last, *tmp_headerlist;
    header_line *last_received = NULL;
    uschar      *address;
    char	mbox_path[512];
    uschar	spamd_buffer2[32600];
    int		max_len, len;
    int		spamd_sock = 0;
    struct	hostent *he;
    struct	in_addr in;
    struct	sockaddr_un server;
#ifndef NO_POLL_H
    int result;
    struct pollfd pollfd;
#endif
    int		offset;
    uschar	spamd_buffer[32600];
    time_t	start;
    size_t	read, wrote;
    int		i;

    arg_socket_addr = argv[0];
    arg_defer_ok = argv[1];
    arg_user_name = argv[2];
    arg_spamd_command = argv[3];

    if (argc < 3) {
	defer_ok = 0;
    } else if (
	    (strcmpic(arg_defer_ok,US"1") == 0)
	|| (strcmpic(arg_defer_ok,US"yes") == 0)
	|| (strcmpic(arg_defer_ok,US"true") == 0)
	|| (strcmpic(arg_defer_ok,US"defer_ok") == 0)
	) {
	defer_ok = 1;
    } else {
	defer_ok = 0;
    }
debug_printf("  defer_ok: %d\n", defer_ok);

    if (argc < 3) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "spamd dlfunc: Bad number of arguments: %d", argc);
	*yield = string_sprintf("spamd dlfunc: Bad number of arguments: %d", argc);
	goto RETURN_DEFER;
    }

    if ((arg_socket_addr == NULL) || (arg_socket_addr[0] == 0)) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "spamd dlfunc: Socket address expected");
	*yield = string_sprintf("spamd dlfunc: Socket address expected");
	goto RETURN_DEFER;
    }

    if ((arg_user_name == NULL) || (arg_user_name[0] == 0)) {
	log_write(0, LOG_MAIN|LOG_PANIC,
	    "spamd dlfunc: Username expected");
	*yield = string_sprintf("spamd dlfunc: Username expected");
	goto RETURN_DEFER;
    }

    if ((arg_spamd_command == NULL) || (arg_spamd_command[0] == 0)) {
	spamd_command = SPAM_COMMAND_REPORT;
    } else if (strcmpic(arg_spamd_command,US"process") == 0) {
	spamd_command = SPAM_COMMAND_PROCESS;
    } else {
	spamd_command = SPAM_COMMAND_REPORT;
    }
debug_printf("  SPAMD command: %s\n", (spamd_command == SPAM_COMMAND_REPORT ? "REPORT" : "PROCESS"));

// get message body stream

    sprintf(mbox_path, "%s/input/%s-D", spool_directory, message_id);
debug_printf("  Open spool file: %s\n", mbox_path);
    mbox_file = fopen(mbox_path,"rb");

    if (!mbox_file) {
	*yield = string_copy((uschar *)"dspam dlfunc: Unable to spool message");
	return(defer_ok ? OK : ERROR);
    }

    (void)fseek(mbox_file, 0, SEEK_END);
    mbox_size = ftell(mbox_file);
debug_printf("  Total spool file size: %d\n", mbox_size);
    mbox_size -= SPOOL_DATA_START_OFFSET;
debug_printf("  Spool file size: %d\n", mbox_size);
debug_printf("  fseek %d, %d\n", SPOOL_DATA_START_OFFSET, SEEK_SET);
    (void)fseek(mbox_file, SPOOL_DATA_START_OFFSET, SEEK_SET);

    start = time(NULL);
/* socket does not start with '/' -> network socket */
    if (arg_socket_addr[0] != '/') {
	if (sscanf(CS arg_socket_addr, "%s %u", tcp_addr, &tcp_port) != 2 ) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
		"spamd dlfunc: Invalid spamd address: '%s'", arg_socket_addr);
	    *yield = string_sprintf("spamd dlfunc: Invalid spamd address: '%s'", arg_socket_addr);
	    goto RETURN_DEFER;
	}

    	/* Lookup the host */
    	if((he = gethostbyname(CS tcp_addr)) == 0) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
    		"spamd dlfunc: failed to lookup host '%s'", tcp_addr);
	    *yield = string_sprintf("spamd dlfunc: failed to lookup host '%s'", tcp_addr);
	    goto RETURN_DEFER;
    	}

    	in = *(struct in_addr *) he->h_addr_list[0];

/* contact a spamd */

	if ((spamd_sock = ip_socket(SOCK_STREAM, AF_INET)) < 0) {
    	    log_write(0, LOG_MAIN|LOG_PANIC,
	        "spamd dlfunc: TCP socket creation failed: %s", strerror(errno));
	    *yield = string_sprintf("spamd dlfunc: TCP socket creation failed: %s", strerror(errno));
	    goto RETURN_DEFER;
	};

	if (ip_connect(spamd_sock, AF_INET, (uschar*)inet_ntoa(in), tcp_port, 5) < 0) {
	    if (spamd_sock >= 0) (void)close(spamd_sock);
    	    log_write(0, LOG_MAIN|LOG_PANIC,
	        "spamd dlfunc: connection to %s, port %u failed: %s", tcp_addr, tcp_port, strerror(errno));
	    *yield = string_sprintf("spamd dlfunc: connection to %s, port %u failed: %s", tcp_addr, tcp_port, strerror(errno));
	    goto RETURN_DEFER;
	}

debug_printf("  Use TCP socket %s:%d\n", tcp_addr, tcp_port);
    } else {
	if ((spamd_sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
    	        "spamd dlfunc: Unable to acquire socket (%s)", strerror(errno));
	    *yield = string_sprintf("spamd dlfunc: Unable to acquire socket (%s)", strerror(errno));
	    goto RETURN_DEFER;
	}

	server.sun_family = AF_UNIX;
	Ustrcpy(server.sun_path, arg_socket_addr);

	if (connect(spamd_sock, (struct sockaddr *) &server, sizeof(struct sockaddr_un)) < 0) {
	    log_write(0, LOG_MAIN|LOG_PANIC,
                "spamd dlfunc: Unable to connect to UNIX socket %s (%s)", socket, strerror(errno) );
	    *yield = string_sprintf("spamd dlfunc: Unable to connect to UNIX socket %s (%s)", socket, strerror(errno) );
	    goto RETURN_DEFER;
        }

debug_printf("  Use UNIX Domain socket %s\n", arg_socket_addr);
    }

// now we are connected to spamd on spamd_sock

    memset(spamd_buffer2, 0, sizeof(spamd_buffer2));
    offset = 0;

    address = expand_string(US"${sender_address}");

    if (address && *address) {
	s = string_sprintf("Return-path: <%s>\n", address);
	max_len = sizeof(spamd_buffer2) - offset - 1;
	len = Ustrlen(s);
	if (len > max_len) len = max_len;
        Ustrncpy(spamd_buffer2 + offset, s, len);
	offset += len;
    }

//    address = expand_string(US"${if def:received_for{$received_for}}");
    address = expand_string(US"${received_for}");
    if (!address || !*address) address = expand_string(US"${recipients}");
    if (!address || !*address) address = expand_string(US"${local_part}@${domain}");

    if (address && *address) {
	s = string_sprintf("Envelope-To: %s\n", address);
	max_len = sizeof(spamd_buffer2) - offset - 1;
	len = Ustrlen(s);
	if (len > max_len) len = max_len;
        Ustrncpy(spamd_buffer2 + offset, s, len);
	offset += len;
    }

    s = string_sprintf("Delivery-date: %s\n", tod_stamp(tod_full));
    max_len = sizeof(spamd_buffer2) - offset - 1;
    len = Ustrlen(s);
    if (len > max_len) len = max_len;
    Ustrncpy(spamd_buffer2 + offset, s, len);
    offset += len;

    // create a copy of original headers list
    tmp_headerlist = NULL;
    header_last = NULL;
    for (my_header = header_list; my_header; my_header = my_header->next) {
	if ((my_header->type != '*') && (my_header->type != htype_old)) {

	    header_new = store_get(sizeof(header_line));
	    header_new->text = string_copyn(my_header->text, my_header->slen);
	    header_new->slen = my_header->slen;
	    header_new->type = my_header->type;
	    header_new->next = NULL;
//debug_printf("  create a copy of header item: '%s'\n", header_new->text);

	    if (tmp_headerlist == NULL) tmp_headerlist = header_new;
	    if (header_last != NULL) header_last->next = header_new;
	    header_last = header_new;
	}
    }

    // headers removed by acl_check_data
    if (acl_removed_headers != NULL) {
	for (my_header = tmp_headerlist; my_header != NULL; my_header = my_header->next) {
	    uschar *list;

	    list = acl_removed_headers;

	    int sep = ':';         // This is specified as a colon-separated list
	    uschar buffer[128];
	    while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) {
		int len = Ustrlen(s);
		if (header_testname(my_header, s, len, FALSE)) {
//debug_printf("  header removed by acl_check_data: '%s'; '%s'\n", s, my_header->text);
		    my_header->type = htype_old;
		}
	    }
	}
    }

    // headers added by acl_check_data
    my_header = acl_added_headers;
    while (my_header != NULL) {
//debug_printf("  header added by acl_check_data: '%s'\n", my_header->text);

	header_new = store_get(sizeof(header_line));
	header_new->text = string_copyn(my_header->text, my_header->slen);
	header_new->slen = my_header->slen;

	switch(my_header->type) {
	case htype_add_top:
	// add header at top
	    header_new->next = tmp_headerlist;
	    tmp_headerlist = header_new;
	    break;

	case htype_add_rec:
	// add header after Received:
	    if (last_received == NULL) {
    	        last_received = tmp_headerlist;
    	        while (!header_testname(last_received, US"Received", 8, FALSE))
    		    last_received = last_received->next;
    		while (last_received->next != NULL && header_testname(last_received->next, US"Received", 8, FALSE))
    		    last_received = last_received->next;
    	    }
	    header_new->next = last_received->next;
	    last_received->next = header_new;
	    break;

	case htype_add_rfc:
	// add header before any header which is NOT Received: or Resent-
	    last_received = tmp_headerlist;
	    while ( (last_received->next != NULL) &&
            ( (header_testname(last_received->next, US"Received", 8, FALSE)) ||
              (header_testname_incomplete(last_received->next, US"Resent-", 7, FALSE)) ) )
        	last_received = last_received->next;
	// last_received now points to the last Received: or Resent-* header
	// in an uninterrupted chain of those header types (seen from the beginning
	// of all headers. Our current header must follow it.
	    header_new->next = last_received->next;
	    last_received->next = header_new;
	    break;

	default:
	// htype_add_bot
	// add header at bottom
	    header_new->next = NULL;
	    header_last->next = header_new;
	    break;
	}

	if (header_new->next == NULL) header_last = header_new;

	my_header = my_header->next;
    }

    // copy all the headers to data buffer
    my_header = tmp_headerlist;
    while (my_header) {
	if (my_header->type != htype_old) {
	    max_len = sizeof(spamd_buffer2) - offset - 1;
	    len = my_header->slen;
    	    if (len > max_len) len = max_len;
    	    Ustrncpy(spamd_buffer2 + offset, my_header->text, len);
	    offset += len;
//debug_printf("  copy header item: '%s'\n", my_header->text);
	}

	if (my_header->text) store_release(my_header->text);
	header_last = my_header;
	my_header = my_header->next;
	if (header_last) store_release(header_last);
    }

    s = string_sprintf("\r\n");
    max_len = sizeof(spamd_buffer2) - offset - 1;
    len = Ustrlen(s);
    if (len > max_len) len = max_len;
    Ustrncpy(spamd_buffer2 + offset, s, len);
    offset += len;

debug_printf("  Headers size: %d\n", offset);
    mbox_size += offset;
debug_printf("  Total message size: %d\n", mbox_size);

// copy request to buffer
    string_format(spamd_buffer,
           sizeof(spamd_buffer),
           "%s SPAMC/1.2\r\nUser: %s\r\nContent-length: %ld\r\n\r\n",
	   (spamd_command == SPAM_COMMAND_PROCESS ? "PROCESS" : "REPORT"),
           arg_user_name,
           mbox_size);

// send our request
    if (send(spamd_sock, spamd_buffer, Ustrlen(spamd_buffer), 0) < 0) {
	log_write(0, LOG_MAIN|LOG_PANIC,
    	    "spamd dlfunc: spamd send failed: %s", strerror(errno));
	goto RETURN_DEFER;
    }

  /*
   * now send the data buffer and spool file
   */

    Ustrcpy(big_buffer, "sending data block");
debug_printf("sending data block\n");

debug_printf("  Send to socket: %s", spamd_buffer2);
    wrote = send(spamd_sock, spamd_buffer2, strlen(spamd_buffer2), 0);
    if (wrote == -1) goto WRITE_FAILED;

  /*
   * Note: poll() is not supported in OSX 10.2.
   */

#ifndef NO_POLL_H
    pollfd.fd = spamd_sock;
    pollfd.events = POLLOUT;
#endif
//    (void)fcntl(spamd_sock, F_SETFL, O_NONBLOCK);
    do {
        read = fread(spamd_buffer,1,sizeof(spamd_buffer),mbox_file);
if (read < sizeof(spamd_buffer)) spamd_buffer[read] = 0;
//debug_printf("  Read from file: %s", spamd_buffer);
        if (read > 0) {
	    offset = 0;
again:

#ifndef NO_POLL_H
	    result = poll(&pollfd, 1, 1000);
	    if (result == -1 && errno == EINTR)
	        continue;
	    else if (result < 1) {
	        if (result == -1)
		    log_write(0, LOG_MAIN|LOG_PANIC,
		        "spamd dlfunc: %s on spamd socket", strerror(errno));
		else {
		    if (time(NULL) - start < SPAMD_TIMEOUT)
		        goto again;
		    log_write(0, LOG_MAIN|LOG_PANIC,
		        "spamd dlfunc: timed out writing spamd socket");
		    *yield = string_sprintf("spamd dlfunc: timed out writing spamd socket");
		}
		goto RETURN_DEFER;
	    }
#endif
	    wrote = send(spamd_sock, spamd_buffer + offset, read - offset, 0);
//debug_printf("  Send to socket %d bytes: %s", read - offset, spamd_buffer + offset);
	    if (wrote == -1) goto WRITE_FAILED;
	    if (offset + wrote != read) {
	        offset += wrote;
	        goto again;
	    }
	}
    } while (!feof(mbox_file) && !ferror(mbox_file));

    if (ferror(mbox_file)) {
        log_write(0, LOG_MAIN|LOG_PANIC,
	    "spamd dlfunc: error reading spool file: %s", strerror(errno));
	*yield = string_sprintf("spamd dlfunc: error reading spool file: %s", strerror(errno));
	goto RETURN_DEFER;
    }

  /*
   read spamd response using what's left of the timeout.
   */

    memset(spamd_buffer, 0, sizeof(spamd_buffer));
    offset = 0;
    while((i = ip_recv(spamd_sock,
                     spamd_buffer + offset,
                     sizeof(spamd_buffer) - offset - 1,
                     SPAMD_TIMEOUT - time(NULL) + start)) > 0 ) {
	offset += i;
    }

/* error handling */
    if((i <= 0) && (errno != 0)) {
	log_write(0, LOG_MAIN|LOG_PANIC,
    	    "spamd dlfunc: error reading from spamd socket: %s", strerror(errno));
	*yield = string_sprintf("spamd dlfunc: error reading from spamd socket: %s", strerror(errno));
	goto RETURN_DEFER;
    }

    if (spamd_command == SPAM_COMMAND_PROCESS) {
	s = Ustrstr(spamd_buffer, "\n\r\n");
	if (s == NULL) s = Ustrstr(spamd_buffer, "\n\n");
	p = s + 1;
	if (p != NULL) {
	    s = Ustrstr(p, "\n\r\n");
	    if (s == NULL) s = Ustrstr(p, "\n\n");
	    if (s != NULL) s[1] = '\0';
	}
    }

//debug_printf("read from socket: %s", spamd_buffer);

    if (spamd_sock >= 0) (void)close(spamd_sock);
    if (mbox_file >= 0) (void)fclose(mbox_file);

    *yield = string_sprintf("SPAMD answer: %s", spamd_buffer);

    return OK;

/* Come here if any call to read_response, other than a response after the data
phase, failed. Analyse the error, and if isn't too bad, send a QUIT
command. Wait for the response with a short timeout, so we don't wind up this
process before the far end has had time to read the QUIT. */

WRITE_FAILED:
{
    log_write(0, LOG_MAIN|LOG_PANIC,
	"spamd dlfunc: %s on spamd socket", strerror(errno));
    *yield = string_sprintf("spamd dlfunc: %s on spamd socket", strerror(errno));
    goto RETURN_DEFER;
}

RESPONSE_FAILED:
{
    int code;
    int save_errno;
    int more_errno;
    uschar message_buffer[256];
    uschar *message;

    save_errno = errno;

    message = &message_buffer[0];

    log_write(0, LOG_MAIN|LOG_PANIC, "spamd dlfunc: %s", message);
    *yield = string_sprintf("spamd dlfunc: %s", message);

    goto RETURN_DEFER;
}

RETURN_DEFER:
{
    if (spamd_sock >= 0) (void)close(spamd_sock);
    if (mbox_file >= 0) (void)fclose(mbox_file);

    return(defer_ok ? OK : ERROR);
}

    return OK;
}