/**
*      Much of the FTP code was inspired by the nanoftp.c module from
*      libxml2 (Copyright Daniel Veillard, 2003).  The routines have been
*      modified to fit the needs of the Motion project.
*
*      Copyright 2005, William M. Brack
*      This software is distributed under the GNU Public license Version 2.
*      See also the file 'COPYING'.
*
*/
#include "motion.h"  /* needs to come first, because _GNU_SOURCE_ set there */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <regex.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <netinet/in.h>

#include "netcam_ftp.h"

/**
* ftp_new_context
*
*      Create a new FTP context structure
*
* Parameters
*
*       None
*
* Returns:     Pointer to the newly-created structure, NULL if error
*
*/
ftp_context_pointer ftp_new_context(void)
{
	ftp_context_pointer ret;

	/* note that mymalloc will exit on any problem */
	ret = mymalloc(sizeof(ftp_context));

	memset(ret, 0, sizeof(ftp_context));
	ret->control_file_desc = -1;                /* no control connection yet */
	ret->data_file_desc = -1;                   /* no data connection yet */
	return ret;
}

/**
* ftp_free_context
*
*      Free the resources allocated for this context
*
* Parameters
*
*      ctxt    Pointer to the ftp_context structure
*
* Returns:     Nothing
*
*/
void ftp_free_context(ftp_context_pointer ctxt)
{
	if (ctxt == NULL)
		return;

	if (ctxt->path != NULL)
		free(ctxt->path);

	if (ctxt->user)
		free(ctxt->user);

	if (ctxt->passwd)
		free(ctxt->passwd);

	if (ctxt->control_file_desc >= 0)
		close(ctxt->control_file_desc);

	free(ctxt);
}

/**
* ftp_parse_response
*
*      Parses the answer from the server, extracting the numeric code.
*
* Parameters:
*
*      buf     the buffer containing the response
*      len     the buffer length
*
* Returns:
*     0 for errors
*     +XXX for last line of response
*     -XXX for response to be continued
*/
static int ftp_parse_response(char *buf, int len) {
	int val = 0;

	if (len < 3)
		return(-1);
	if ((*buf >= '0') && (*buf <= '9'))
		val = val * 10 + (*buf - '0');
	else
		return(0);

	buf++;

	if ((*buf >= '0') && (*buf <= '9'))
		val = val * 10 + (*buf - '0');
	else
		return(0);

	buf++;

	if ((*buf >= '0') && (*buf <= '9'))
		val = val * 10 + (*buf - '0');
	else
		return(0);

	buf++;

	if (*buf == '-')
		return(-val);

	return(val);
}

/**
* ftp_get_more
*
*      Read more information from the FTP control connection
*
* Parameters:
*
*      ctxt    pointer to an FTP context
*
* Returns the number of bytes read, < 0 indicates an error
*/
static int ftp_get_more(ftp_context_pointer ctxt) {
	int len;
	int size;

	/* Validate that our context structure is valid */
	if ((ctxt == NULL) || (ctxt->control_file_desc < 0))
		return(-1);

	if ((ctxt->control_buffer_index < 0) || (ctxt->control_buffer_index > FTP_BUF_SIZE))
		return(-1);

	if ((ctxt->control_buffer_used < 0) || (ctxt->control_buffer_used > FTP_BUF_SIZE))
		return(-1);

	if (ctxt->control_buffer_index > ctxt->control_buffer_used)
		return(-1);

	/*
	* First pack the control buffer
	*/
	if (ctxt->control_buffer_index > 0) {
		memmove(&ctxt->control_buffer[0],
		&ctxt->control_buffer[ctxt->control_buffer_index],
		ctxt->control_buffer_used - ctxt->control_buffer_index);
		ctxt->control_buffer_used -= ctxt->control_buffer_index;
		ctxt->control_buffer_index = 0;
	}
	size = FTP_BUF_SIZE - ctxt->control_buffer_used;

	if (size == 0) {
		return(0);
	}

	/*
	* Read the amount left on the control connection
	*/
	if ((len = recv(ctxt->control_file_desc,
	&ctxt->control_buffer[ctxt->control_buffer_index],
	size, 0)) < 0) {
		motion_log(LOG_ERR, 1, "recv failed in ftp_get_more");
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}
	ctxt->control_buffer_used += len;
	ctxt->control_buffer[ctxt->control_buffer_used] = 0;

	return(len);
}

/**
* ftp_get_response
*
*      Read the response from the FTP server after a command.
*
* Parameters
*
*      ctxt    pointer to an FTP context
*
* Returns the code number
*/
static int ftp_get_response(ftp_context_pointer ctxt) {
	char *ptr, *end;
	int len;
	int res = -1, cur = -1;

	if ((ctxt == NULL) || (ctxt->control_file_desc < 0))
	return(-1);

	get_more:
	/*
	* Assumes everything up to control_buffer[control_buffer_index] has been read
	* and analyzed.
	*/
	len = ftp_get_more(ctxt);
	if (len < 0) {
		return(-1);
	}
	if ((ctxt->control_buffer_used == 0) && (len == 0)) {
		return(-1);
	}
	ptr = &ctxt->control_buffer[ctxt->control_buffer_index];
	end = &ctxt->control_buffer[ctxt->control_buffer_used];

	while (ptr < end) {
		cur = ftp_parse_response(ptr, end - ptr);
		if (cur > 0) {
			/*
			* Successfully scanned the control code, skip
			* till the end of the line, but keep the index to be
			* able to analyze the result if needed.
			*/
			res = cur;
			ptr += 3;
			ctxt->control_buffer_answer = ptr - ctxt->control_buffer;
			while ((ptr < end) && (*ptr != '\n')) ptr++;
			if (*ptr == '\n') ptr++;
			if (*ptr == '\r') ptr++;
			break;
		}
		while ((ptr < end) && (*ptr != '\n'))
		ptr++;
		if (ptr >= end) {
			ctxt->control_buffer_index = ctxt->control_buffer_used;
			goto get_more;
		}
		if (*ptr != '\r') ptr++;
	}

	if (res < 0)
	goto get_more;
	ctxt->control_buffer_index = ptr - ctxt->control_buffer;
	return(res / 100);
}

/**
* Send the user authentication
*/

static int ftp_send_user(ftp_context_pointer ctxt) {
	char buf[200];
	int len;
	int res;

	if (ctxt->user == NULL)
	snprintf(buf, sizeof(buf), "USER anonymous\r\n");
	else
	snprintf(buf, sizeof(buf), "USER %s\r\n", ctxt->user);
	buf[sizeof(buf) - 1] = 0;
	len = strlen(buf);
	res = send(ctxt->control_file_desc, buf, len, 0);
	if (res < 0) {
		motion_log(LOG_ERR, 1, "send failed in ftp_send_user");
		return(res);
	}
	return(0);
}

/**
* Send the password authentication
*/

static int ftp_send_passwd(ftp_context_pointer ctxt) {
	char buf[200];
	int len;
	int res;

	if (ctxt->passwd == NULL)
	snprintf(buf, sizeof(buf), "PASS anonymous@\r\n");
	else
	snprintf(buf, sizeof(buf), "PASS %s\r\n", ctxt->passwd);
	buf[sizeof(buf) - 1] = 0;
	len = strlen(buf);
	res = send(ctxt->control_file_desc, buf, len, 0);
	if (res < 0) {
		motion_log(LOG_ERR, 1, "send failed in ftp_send_passwd");
		return(res);
	}
	return(0);
}

/**
* ftp_quit
*
*      Send a QUIT command to the server
*
* Parameters:
*
*      ctxt    pointer to an FTP context
*
* Returns -1 in case of error, 0 otherwise
*/


static int ftp_quit(ftp_context_pointer ctxt) {
	char buf[200];
	int len, res;

	if ((ctxt == NULL) || (ctxt->control_file_desc < 0))
	return(-1);

	snprintf(buf, sizeof(buf), "QUIT\r\n");
	len = strlen(buf);
	res = send(ctxt->control_file_desc, buf, len, 0);
	if (res < 0) {
		motion_log(LOG_ERR, 1, "send failed in ftp_quit");
		return(res);
	}
	return(0);
}

/**
* ftp_connect
*
*      Tries to open a control connection
*
* Parameters:
*
*      ctxt    an FTP context
*
* Returns -1 in case of error, 0 otherwise
*/

int ftp_connect(netcam_context_ptr netcam) {
	ftp_context_pointer ctxt;
	struct hostent *hp;
	int port;
	int res;
	int addrlen = sizeof (struct sockaddr_in);

	if (netcam == NULL)
	return -1;
	ctxt = netcam->ftp;
	if (ctxt == NULL)
	return(-1);
	if (netcam->connect_host == NULL)
	return(-1);

	/*
	* do the blocking DNS query.
	*/
	port = netcam->connect_port;
	if (port == 0)
	port = 21;

	memset (&ctxt->ftp_address, 0, sizeof(ctxt->ftp_address));

	hp = gethostbyname (netcam->connect_host);
	if (hp == NULL) {
		motion_log(LOG_ERR, 1, "gethostbyname failed in ftp_connect");
		return (-1);
	}
	if ((unsigned int) hp->h_length >
	sizeof(((struct sockaddr_in *)&ctxt->ftp_address)->sin_addr)) {
		motion_log(LOG_ERR, 1, "gethostbyname address mismatch "
		"in ftp_connect");
		return (-1);
	}

	/*
	* Prepare the socket
	*/
	((struct sockaddr_in *)&ctxt->ftp_address)->sin_family = AF_INET;
	memcpy (&((struct sockaddr_in *)&ctxt->ftp_address)->sin_addr,
	hp->h_addr_list[0], hp->h_length);
	((struct sockaddr_in *)&ctxt->ftp_address)->sin_port =
	(u_short)htons ((unsigned short)port);
	ctxt->control_file_desc = socket (AF_INET, SOCK_STREAM, 0);
	addrlen = sizeof (struct sockaddr_in);

	if (ctxt->control_file_desc < 0) {
		motion_log(LOG_ERR, 1, "socket failed");
		return(-1);
	}

	/*
	* Do the connect.
	*/
	if (connect(ctxt->control_file_desc, (struct sockaddr *) &ctxt->ftp_address,
	addrlen) < 0) {
		motion_log(LOG_ERR, 1, "Failed to create a connection");
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}

	/*
	* Wait for the HELLO from the server.
	*/
	res = ftp_get_response(ctxt);
	if (res != 2) {
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}

	/*
	* Do the authentication
	*/
	res = ftp_send_user(ctxt);
	if (res < 0) {
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}
	res = ftp_get_response(ctxt);
	switch (res) {
		case 2:
		return(0);
		case 3:
		break;
		case 1:
		case 4:
		case 5:
		case -1:
		default:
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}
	res = ftp_send_passwd(ctxt);
	if (res < 0) {
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}
	res = ftp_get_response(ctxt);
	switch (res) {
		case 2:
		break;
		case 3:
		motion_log(LOG_ERR, 0, "FTP server asking for ACCT on anonymous");
		case 1:
		case 4:
		case 5:
		case -1:
		default:
		close(ctxt->control_file_desc); ctxt->control_file_desc = -1;
		ctxt->control_file_desc = -1;
		return(-1);
	}

	return(0);
}

/**
* ftp_get_connection
*
*      Try to open a data connection to the server.
*
* Parameters:
*
*      ctxt    pointer to an FTP context
*
* Returns -1 in case of error, 0 otherwise
*/

static int ftp_get_connection(ftp_context_pointer ctxt) {
	char buf[200], *cur;
	int len, i;
	int res;
	int on;
	unsigned char ad[6], *adp, *portp;
	unsigned int temp[6];
	struct sockaddr_in data_address;
	unsigned int data_address_length;

	if (ctxt == NULL)
	return(-1);

	/* set up a socket for our data address */
	if (ctxt->data_file_desc != -1)
	close(ctxt->data_file_desc);
	memset (&data_address, 0, sizeof(data_address));
	ctxt->data_file_desc = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (ctxt->data_file_desc < 0) {
		motion_log(LOG_ERR, 1, "socket failed");
		return (-1);
	}
	on = 1;
	if (setsockopt(ctxt->data_file_desc, SOL_SOCKET, SO_REUSEADDR,
	(char *)&on, sizeof(on)) < 0) {
		motion_log(LOG_ERR, 1, "setting socket option SO_REUSEADDR");
		return -1;
	}

	((struct sockaddr_in *)&data_address)->sin_family = AF_INET;
	data_address_length = sizeof (struct sockaddr_in);

	if (ctxt->passive) {
		/* send PASV command over control channel */
		snprintf (buf, sizeof(buf), "PASV\r\n");
		len = strlen (buf);
		res = send(ctxt->control_file_desc, buf, len, 0);
		if (res < 0) {
			motion_log(LOG_ERR, 1, "send failed in ftp_get_connection");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return(res);
		}
		/* check server's answer */
		res = ftp_get_response(ctxt);
		if (res != 2) {
			if (res == 5) {
				close(ctxt->data_file_desc);
				ctxt->data_file_desc = -1;
				return(-1);
			} else {
				/*
				* retry with an active connection
				*/
				close(ctxt->data_file_desc);
				ctxt->data_file_desc = -1;
				ctxt->passive = 0;
			}
		}
		/* parse the IP address and port supplied by the server */
		cur = &ctxt->control_buffer[ctxt->control_buffer_answer];
		while (((*cur < '0') || (*cur > '9')) && *cur != '\0')
		cur++;
		if (sscanf (cur, "%u,%u,%u,%u,%u,%u", &temp[0], &temp[1], &temp[2],
		&temp[3], &temp[4], &temp[5]) != 6) {
			motion_log(LOG_ERR, 0, "Invalid answer to PASV");
			if (ctxt->data_file_desc != -1) {
				close (ctxt->data_file_desc);
				ctxt->data_file_desc = -1;
			}
			return (-1);
		}
		for (i=0; i<6; i++)
		ad[i] = (unsigned char) (temp[i] & 0xff) ;
		memcpy (&((struct sockaddr_in *)&data_address)->sin_addr, &ad[0], 4);
		memcpy (&((struct sockaddr_in *)&data_address)->sin_port, &ad[4], 2);

		/* Now try to connect to the data port */
		if (connect(ctxt->data_file_desc, (struct sockaddr *) &data_address,
		    data_address_length) < 0) {
			motion_log(LOG_ERR, 1, "Failed to create a data connection");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return (-1);
		}
	} else {
		/*
		* We want to bind to a port to receive the data.  To do this,
		* we need the address of our host.  One easy way to get it is
		* to get the info from the control connection that we have
		* with the remote server
		*/
		getsockname(ctxt->control_file_desc, (struct sockaddr *)&data_address,
		            &data_address_length);
		((struct sockaddr_in *)&data_address)->sin_port = 0;

		/* bind to the socket - should give us a unique port */
		if (bind(ctxt->data_file_desc, (struct sockaddr *) &data_address,
		    data_address_length) < 0) {
			motion_log(LOG_ERR, 1, "bind failed");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return (-1);
		}

		/* we get the port number by reading back in the sockaddr */
		getsockname(ctxt->data_file_desc, (struct sockaddr *)&data_address,
		            &data_address_length);

		/* set up a 'listen' on the port to get the server's connection */
		if (listen(ctxt->data_file_desc, 1) < 0) {
			motion_log(LOG_ERR, 1, "listen failed");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return (-1);
		}

		/* now generate the PORT command */
		adp = (unsigned char *) &((struct sockaddr_in *)&data_address)->sin_addr;
		portp = (unsigned char *) &((struct sockaddr_in *)&data_address)->sin_port;
		snprintf (buf, sizeof(buf), "PORT %d,%d,%d,%d,%d,%d\r\n",
		adp[0] & 0xff, adp[1] & 0xff, adp[2] & 0xff, adp[3] & 0xff,
		portp[0] & 0xff, portp[1] & 0xff);

		buf[sizeof(buf) - 1] = 0;
		len = strlen(buf);

		/* send the PORT command to the server */
		res = send(ctxt->control_file_desc, buf, len, 0);

		if (res < 0) {
			motion_log(LOG_ERR, 1, "send failed in ftp_get_connection");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return(res);
		}

		res = ftp_get_response(ctxt);

		if (res != 2) {
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return(-1);
		}
	}

	return(ctxt->data_file_desc);
}

/**
* ftp_close_connection
*
*      Close the data connection from the server
*
* Parameters:
*
*      ctxt    Pointer to an FTP context
*
* Returns -1 in case of error, 0 otherwise
*/

static int ftp_close_connection(ftp_context_pointer ctxt) {
	int res;
	fd_set rfd, efd;
	struct timeval tv;

	if ((ctxt == NULL) || (ctxt->control_file_desc < 0))
		return(-1);

	close(ctxt->data_file_desc);
	ctxt->data_file_desc = -1;

	/* Check for data on the control channel */
	tv.tv_sec = 15;
	tv.tv_usec = 0;
	FD_ZERO(&rfd);
	FD_SET(ctxt->control_file_desc, &rfd);
	FD_ZERO(&efd);
	FD_SET(ctxt->control_file_desc, &efd);
	res = select(ctxt->control_file_desc + 1, &rfd, NULL, &efd, &tv);

	if (res < 0) {
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
		return(-1);
	}

	if (res == 0) {             /* timeout */
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
	} else {                    /* read the response */
		res = ftp_get_response(ctxt);

		if (res != 2) {            /* should be positive completion (2) */
			close(ctxt->control_file_desc);
			ctxt->control_file_desc = -1;
			return(-1);
		}
	}

	return(0);
}

/**
* ftp_get_socket
*
*      Initiate fetch of the given file from the server.
*
* Parameters:
*
*      ctxt            an FTP context
*
* Returns the socket for the data connection, or <0 in case of error
*/


int ftp_get_socket(ftp_context_pointer ctxt) {
	char buf[300];
	int res, len;
	int acfd;

	if ((ctxt == NULL) || (ctxt->path == NULL))
		return(-1);

	/* Set up the data connection */
	ctxt->data_file_desc = ftp_get_connection(ctxt);

	if (ctxt->data_file_desc == -1)
		return(-1);

	/* generate a "retrieve" command for the file */
	snprintf(buf, sizeof(buf), "RETR %s\r\n", ctxt->path);
	buf[sizeof(buf) - 1] = 0;
	len = strlen(buf);

	/* send it to the server */
	res = send(ctxt->control_file_desc, buf, len, 0);

	if (res < 0) {
		motion_log(LOG_ERR, 1, "send failed in ftp_get_socket");
		close(ctxt->data_file_desc);
		ctxt->data_file_desc = -1;
		return(res);
	}

	/* check the answer */
	res = ftp_get_response(ctxt);

	if (res != 1) {
		close(ctxt->data_file_desc);
		ctxt->data_file_desc = -1;
		return(-res);
	}

	/*
	* if not a passive connection, need to do an accept to get the
	* connection from the server
	*/
	if (!ctxt->passive) {
		struct sockaddr_in data_address;
		unsigned int data_address_length = sizeof(struct sockaddr_in);

		if ((acfd = accept(ctxt->data_file_desc, (struct sockaddr *)&data_address,
		    &data_address_length)) < 0) {
			motion_log(LOG_ERR, 1, "accept in ftp_get_socket");
			close(ctxt->data_file_desc);
			ctxt->data_file_desc = -1;
			return -1;
		}

		close(ctxt->data_file_desc);
		ctxt->data_file_desc = acfd;
	}

	return(ctxt->data_file_desc);
}
/**
* ftp_send_type
*
* 	Send a TYPE (either 'I' or 'A') command to the server
*
* Parameters
*
*      ctxt    pointer to the ftp_context
*      type    ascii character ('I' or 'A')
*
* Returns      0 for success, negative error code for failure
*
*/
int ftp_send_type(ftp_context_pointer ctxt, char type) {
	char buf[100], utype;
	int len, res;

	utype = toupper(type);
	/* Assure transfer will be in "image" mode */
	snprintf(buf, sizeof(buf), "TYPE I\r\n");
	len = strlen(buf);
	res = send(ctxt->control_file_desc, buf, len, 0);

	if (res < 0) {
		motion_log(LOG_ERR, 1, "send failed in ftp_get_socket");
		close(ctxt->data_file_desc);
		ctxt->data_file_desc = -1;
		return(res);
	}

	res = ftp_get_response(ctxt);

	if (res != 2) {
		close(ctxt->data_file_desc);
		ctxt->data_file_desc = -1;
		return(-res);
	}

	return 0;
}

/**
* ftp_read
*
*      This function tries to read len bytes from the existing FTP
*      connection and saves them in dest. This is a blocking call.
*
* Parameters:
*      ctxt    the FTP context
*      dest    a buffer
*      len     the buffer length
*
* Returns:     the number of bytes read.
*              0 is an indication of an end of connection.
*              -1 indicates a parameter error.
*/
int ftp_read(ftp_context_pointer ctxt, void *dest, int len) {
	if (ctxt == NULL)
		return(-1);

	if (ctxt->data_file_desc < 0)
		return(0);

	if (dest == NULL)
		return(-1);

	if (len <= 0)
		return(0);

	len = recv(ctxt->data_file_desc, dest, len, 0);

	if (len <= 0) {
		if (len < 0)
			motion_log(LOG_ERR, 1, "recv failed in ftp_read");
		ftp_close_connection(ctxt);
	}

	return(len);
}


/**
* ftp_close
*
*      Close the connection and both control and transport
*
* Parameters:
*
*      ctxt    Pointer to an FTP context
*
* Returns -1 in case of error, 0 otherwise
*/
int ftp_close(ftp_context_pointer ctxt) {
	if (ctxt == NULL)
		return(-1);

	if (ctxt->data_file_desc >= 0) {
		close(ctxt->data_file_desc);
		ctxt->data_file_desc = -1;
	}

	if (ctxt->control_file_desc >= 0) {
		ftp_quit(ctxt);
		close(ctxt->control_file_desc);
		ctxt->control_file_desc = -1;
	}

	ftp_free_context(ctxt);
	return(0);
}