/* vi: set sw=4 ts=4: */
/*
 * wget - retrieve a file using HTTP or FTP
 *
 * Chip Rosenthal Covad Communications <chip@laserlink.net>
 *
 * Note: According to RFC2616 section 3.6.1, "All HTTP/1.1 applications MUST be
 * able to receive and decode the "chunked" transfer-coding, and MUST ignore
 * chunk-extension extensions they do not understand."  
 *
 * This prevents this particular wget app from completely RFC compliant, and as
 * such, prevents it from being used as a general purpose web browser...  This
 * is a design decision, since it makes the code smaller.
 *
 */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ioctl.h>

#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include "busybox.h"

/* Stupid libc5 doesn't define this... */
#ifndef timersub
#define	timersub(a, b, result)						      \
  do {									      \
    (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;			      \
    (result)->tv_usec = (a)->tv_usec - (b)->tv_usec;			      \
    if ((result)->tv_usec < 0) {					      \
      --(result)->tv_sec;						      \
      (result)->tv_usec += 1000000;					      \
    }									      \
  } while (0)
#endif	

struct host_info {
	char *host;
	int port;
	char *path;
	int is_ftp;
	char *user;
};

static void parse_url(char *url, struct host_info *h);
static FILE *open_socket(char *host, int port);
static char *gethdr(char *buf, size_t bufsiz, FILE *fp, int *istrunc);
static int ftpcmd(char *s1, char *s2, FILE *fp, char *buf);
static void progressmeter(int flag);

/* Globals (can be accessed from signal handlers */
static off_t filesize = 0;		/* content-length of the file */
#ifdef BB_FEATURE_WGET_STATUSBAR
static char *curfile;			/* Name of current file being transferred. */
static struct timeval start;	/* Time a transfer started. */
static volatile unsigned long statbytes; /* Number of bytes transferred so far. */
/* For progressmeter() -- number of seconds before xfer considered "stalled" */
static const int STALLTIME = 5;
#endif
		
static void close_and_delete_outfile(FILE* output, char *fname_out, int do_continue)
{
	if (output != stdout && do_continue==0) {
		fclose(output);
		unlink(fname_out);
	}
}

#define close_delete_and_die(s...) { \
	close_and_delete_outfile(output, fname_out, do_continue); \
	error_msg_and_die(s); }


#ifdef BB_FEATURE_WGET_AUTHENTICATION
/*
 *  Base64-encode character string
 *  oops... isn't something similar in uuencode.c?
 *  It would be better to use already existing code
 */
char *base64enc(char *p, char *buf, int len) {

        char al[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
                    "0123456789+/";
		char *s = buf;

        while(*p) {
				if (s >= buf+len-4)
					error_msg_and_die("buffer overflow");
                *(s++) = al[(*p >> 2) & 0x3F];
                *(s++) = al[((*p << 4) & 0x30) | ((*(p+1) >> 4) & 0x0F)];
                *s = *(s+1) = '=';
                *(s+2) = 0;
                if (! *(++p)) break;
                *(s++) = al[((*p << 2) & 0x3C) | ((*(p+1) >> 6) & 0x03)];
                if (! *(++p)) break;
                *(s++) = al[*(p++) & 0x3F];
        }

		return buf;
}
#endif

int wget_main(int argc, char **argv)
{
	int n, try=5, status;
	int port;
	char *proxy;
	char *s, buf[512];
	struct stat sbuf;

	struct host_info server, target;

	FILE *sfp = NULL;			/* socket to web/ftp server			*/
	FILE *dfp = NULL;			/* socket to ftp server (data)		*/
	char *fname_out = NULL;		/* where to direct output (-O)		*/
	int do_continue = 0;		/* continue a prev transfer (-c)	*/
	long beg_range = 0L;		/*   range at which continue begins	*/
	int got_clen = 0;			/* got content-length: from server	*/
	FILE *output;				/* socket to web server				*/
	int quiet_flag = FALSE;		/* Be verry, verry quiet...			*/

	/*
	 * Crack command line.
	 */
	while ((n = getopt(argc, argv, "cqO:")) != EOF) {
		switch (n) {
		case 'c':
			++do_continue;
			break;
		case 'q':
			quiet_flag = TRUE;
			break;
		case 'O':
			/* can't set fname_out to NULL if outputting to stdout, because
			 * this gets interpreted as the auto-gen output filename
			 * case below  - tausq@debian.org
			 */
			fname_out = (strcmp(optarg, "-") == 0 ? (char *)1 : optarg);
			break;
		default:
			show_usage();
		}
	}

	if (argc - optind != 1)
			show_usage();

	parse_url(argv[optind], &target);
	server.host = target.host;
	server.port = target.port;

	/*
	 * Use the proxy if necessary.
	 */
	proxy = getenv(target.is_ftp ? "ftp_proxy" : "http_proxy");
	if (proxy)
		parse_url(xstrdup(proxy), &server);
	
	/* Guess an output filename */
	if (!fname_out) {
		fname_out = 
#ifdef BB_FEATURE_WGET_STATUSBAR
			curfile = 
#endif
			get_last_path_component(target.path);
		if (fname_out==NULL || strlen(fname_out)<1) {
			fname_out = 
#ifdef BB_FEATURE_WGET_STATUSBAR
				curfile = 
#endif
				"index.html";
		}
#ifdef BB_FEATURE_WGET_STATUSBAR
	} else {
		curfile = get_last_path_component(fname_out);
#endif
	}
	if (do_continue && !fname_out)
		error_msg_and_die("cannot specify continue (-c) without a filename (-O)");


	/*
	 * Open the output file stream.
	 */
	if (fname_out != (char *)1) {
		output = xfopen( fname_out, (do_continue ? "a" : "w") );
	} else {
		output = stdout;
	}

	/*
	 * Determine where to start transfer.
	 */
	if (do_continue) {
		if (fstat(fileno(output), &sbuf) < 0)
			perror_msg_and_die("fstat()");
		if (sbuf.st_size > 0)
			beg_range = sbuf.st_size;
		else
			do_continue = 0;
	}

	if (proxy || !target.is_ftp) {
		/*
		 *  HTTP session
		 */
		do {
			if (! --try)
				close_delete_and_die("too many redirections");

			/*
			 * Open socket to http server
			 */
			if (sfp) fclose(sfp);
			sfp = open_socket(server.host, server.port);
			
			/*
			 * Send HTTP request.
			 */
			if (proxy) {
				fprintf(sfp, "GET %stp://%s:%d/%s HTTP/1.0\r\n", 
					target.is_ftp ? "f" : "ht", target.host,
					target.port, target.path);
			} else {
				fprintf(sfp, "GET /%s HTTP/1.0\r\n", target.path);
			}

			fprintf(sfp, "Host: %s\r\nUser-Agent: Wget\r\n", target.host);

#ifdef BB_FEATURE_WGET_AUTHENTICATION
			if (target.user) {
				fprintf(sfp, "Authorization: Basic %s\r\n",
					base64enc(target.user, buf, sizeof(buf)));
			}
			if (proxy && server.user) {
				fprintf(sfp, "Proxy-Authorization: Basic %s\r\n",
					base64enc(server.user, buf, sizeof(buf)));
			}
#endif

			if (do_continue)
				fprintf(sfp, "Range: bytes=%ld-\r\n", beg_range);
			fprintf(sfp,"Connection: close\r\n\r\n");

			/*
		 	* Retrieve HTTP response line and check for "200" status code.
		 	*/
			if (fgets(buf, sizeof(buf), sfp) == NULL)
				close_delete_and_die("no response from server");
				
			for (s = buf ; *s != '\0' && !isspace(*s) ; ++s)
			;
			for ( ; isspace(*s) ; ++s)
			;
			switch (status = atoi(s)) {
				case 0:
				case 200:
					if (do_continue && output != stdout)
						output = freopen(fname_out, "w", output);
					do_continue = 0;
					break;
				case 300:	/* redirection */
				case 301:
				case 302:
				case 303:
					break;
				case 206:
					if (do_continue)
						break;
					/*FALLTHRU*/
				default:
					chomp(buf);
					close_delete_and_die("server returned error %d: %s", atoi(s), buf);
			}
		
			/*
			 * Retrieve HTTP headers.
			 */
			while ((s = gethdr(buf, sizeof(buf), sfp, &n)) != NULL) {
				if (strcasecmp(buf, "content-length") == 0) {
					filesize = atol(s);
					got_clen = 1;
					continue;
				}
				if (strcasecmp(buf, "transfer-encoding") == 0)
					close_delete_and_die("server wants to do %s transfer encoding", s);

				if (strcasecmp(buf, "location") == 0) {
					if (s[0] == '/')
						target.path = xstrdup(s+1);
					else {
						parse_url(xstrdup(s), &target);
						if (!proxy) {
							server.host = target.host;
							server.port = target.port;
						}
					}
				}
			}
		} while(status >= 300);
		
		dfp = sfp;
	}
	else
	{
		/*
		 *  FTP session
		 */
		if (! target.user)
			target.user = xstrdup("anonymous:busybox@");

		sfp = open_socket(server.host, server.port);
		if (ftpcmd(NULL, NULL, sfp, buf) != 220)
			close_delete_and_die("%s", buf+4);

		/* 
		 * Splitting username:password pair,
		 * trying to log in
		 */
		s = strchr(target.user, ':');
		if (s)
			*(s++) = '\0';
		switch(ftpcmd("USER ", target.user, sfp, buf)) {
			case 230:
				break;
			case 331:
				if (ftpcmd("PASS ", s, sfp, buf) == 230)
					break;
				/* FALLTHRU (failed login) */
			default:
				close_delete_and_die("ftp login: %s", buf+4);
		}
		
		ftpcmd("CDUP", NULL, sfp, buf);
		ftpcmd("TYPE I", NULL, sfp, buf);
		
		/*
		 * Querying file size
		 */
		if (ftpcmd("SIZE /", target.path, sfp, buf) == 213) {
			filesize = atol(buf+4);
			got_clen = 1;
		}
		
		/*
		 * Entering passive mode
		 */
		if (ftpcmd("PASV", NULL, sfp, buf) !=  227)
			close_delete_and_die("PASV: %s", buf+4);
		s = strrchr(buf, ',');
		*s = 0;
		port = atoi(s+1);
		s = strrchr(buf, ',');
		port += atoi(s+1) * 256;
		dfp = open_socket(server.host, port);

		if (do_continue) {
			sprintf(buf, "REST %ld", beg_range);
			if (ftpcmd(buf, NULL, sfp, buf) != 350) {
				if (output != stdout)
					output = freopen(fname_out, "w", output);
				do_continue = 0;
			} else
				filesize -= beg_range;
		}
		
		if (ftpcmd("RETR /", target.path, sfp, buf) > 150)
			close_delete_and_die("RETR: %s", buf+4);

	}


	/*
	 * Retrieve file
	 */
#ifdef BB_FEATURE_WGET_STATUSBAR
	statbytes=0;
	if (quiet_flag==FALSE)
		progressmeter(-1);
#endif
	while ((filesize > 0 || !got_clen) && (n = fread(buf, 1, sizeof(buf), dfp)) > 0) {
		fwrite(buf, 1, n, output);
#ifdef BB_FEATURE_WGET_STATUSBAR
		statbytes+=n;
		if (quiet_flag==FALSE)
			progressmeter(1);
#endif
		if (got_clen)
			filesize -= n;
	}

	if (n == 0 && ferror(dfp))
		perror_msg_and_die("network read error");

	if (!proxy && target.is_ftp) {
		fclose(dfp);
		if (ftpcmd(NULL, NULL, sfp, buf) != 226)
			error_msg_and_die("ftp error: %s", buf+4);
		ftpcmd("QUIT", NULL, sfp, buf);
	}

	exit(EXIT_SUCCESS);
}


void parse_url(char *url, struct host_info *h)
{
	char *cp, *sp, *up;

	if (strncmp(url, "http://", 7) == 0) {
		h->port = 80;
		h->host = url + 7;
		h->is_ftp = 0;
	} else if (strncmp(url, "ftp://", 6) == 0) {
		h->port = 21;
		h->host = url + 6;
		h->is_ftp = 1;
	} else
		error_msg_and_die("not an http or ftp url: %s", url);

	sp = strchr(h->host, '/');
	if (sp != NULL) {
		*sp++ = '\0';
		h->path = sp;
	} else
		h->path = "";

	up = strrchr(h->host, '@');
	if (up != NULL) {
		h->user = h->host;
		*up++ = '\0';
		h->host = up;
	} else
		h->user = NULL;

	cp = strchr(h->host, ':');
	if (cp != NULL) {
		*cp++ = '\0';
		h->port = atoi(cp);
	}

}


FILE *open_socket(char *host, int port)
{
	struct sockaddr_in s_in;
	struct hostent *hp;
	int fd;
	FILE *fp;

	memset(&s_in, 0, sizeof(s_in));
	s_in.sin_family = AF_INET;
	if ((hp = (struct hostent *) gethostbyname(host)) == NULL)
		error_msg_and_die("cannot resolve %s", host);
	memcpy(&s_in.sin_addr, hp->h_addr_list[0], hp->h_length);
	s_in.sin_port = htons(port);

	/*
	 * Get the server onto a stdio stream.
	 */
	if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
		perror_msg_and_die("socket()");
	if (connect(fd, (struct sockaddr *) &s_in, sizeof(s_in)) < 0)
		perror_msg_and_die("connect(%s)", host);
	if ((fp = fdopen(fd, "r+")) == NULL)
		perror_msg_and_die("fdopen()");

	return fp;
}


char *gethdr(char *buf, size_t bufsiz, FILE *fp, int *istrunc)
{
	char *s, *hdrval;
	int c;

	*istrunc = 0;

	/* retrieve header line */
	if (fgets(buf, bufsiz, fp) == NULL)
		return NULL;

	/* see if we are at the end of the headers */
	for (s = buf ; *s == '\r' ; ++s)
		;
	if (s[0] == '\n')
		return NULL;

	/* convert the header name to lower case */
	for (s = buf ; isalnum(*s) || *s == '-' ; ++s)
		*s = tolower(*s);

	/* verify we are at the end of the header name */
	if (*s != ':')
		error_msg_and_die("bad header line: %s", buf);

	/* locate the start of the header value */
	for (*s++ = '\0' ; *s == ' ' || *s == '\t' ; ++s)
		;
	hdrval = s;

	/* locate the end of header */
	while (*s != '\0' && *s != '\r' && *s != '\n')
		++s;

	/* end of header found */
	if (*s != '\0') {
		*s = '\0';
		return hdrval;
	}

	/* Rats!  The buffer isn't big enough to hold the entire header value. */
	while (c = getc(fp), c != EOF && c != '\n')
		;
	*istrunc = 1;
	return hdrval;
}

static int ftpcmd(char *s1, char *s2, FILE *fp, char *buf)
{
	char *p;
	
	if (s1) {
		if (!s2) s2="";
		fprintf(fp, "%s%s\n", s1, s2);
		fflush(fp);
	}
	
	do {
		p = fgets(buf, 510, fp);
		if (!p)
			perror_msg_and_die("fgets()");
	} while (! isdigit(buf[0]) || buf[3] != ' ');
	
	return atoi(buf);
}

#ifdef BB_FEATURE_WGET_STATUSBAR
/* Stuff below is from BSD rcp util.c, as added to openshh. 
 * Original copyright notice is retained at the end of this file.
 * 
 */ 


static int
getttywidth(void)
{
	struct winsize winsize;

	if (ioctl(fileno(stdout), TIOCGWINSZ, &winsize) != -1)
		return (winsize.ws_col ? winsize.ws_col : 80);
	else
		return (80);
}

static void
updateprogressmeter(int ignore)
{
	int save_errno = errno;

	progressmeter(0);
	errno = save_errno;
}

static void
alarmtimer(int wait)
{
	struct itimerval itv;

	itv.it_value.tv_sec = wait;
	itv.it_value.tv_usec = 0;
	itv.it_interval = itv.it_value;
	setitimer(ITIMER_REAL, &itv, NULL);
}


static void
progressmeter(int flag)
{
	static const char prefixes[] = " KMGTP";
	static struct timeval lastupdate;
	static off_t lastsize;
	struct timeval now, td, wait;
	off_t cursize, abbrevsize;
	double elapsed;
	int ratio, barlength, i, remaining;
	char buf[256];

	if (flag == -1) {
		(void) gettimeofday(&start, (struct timezone *) 0);
		lastupdate = start;
		lastsize = 0;
	}

	(void) gettimeofday(&now, (struct timezone *) 0);
	cursize = statbytes;
	if (filesize != 0) {
		ratio = 100.0 * cursize / filesize;
		ratio = MAX(ratio, 0);
		ratio = MIN(ratio, 100);
	} else
		ratio = 100;

	snprintf(buf, sizeof(buf), "\r%-20.20s %3d%% ", curfile, ratio);

	barlength = getttywidth() - 51;
	if (barlength > 0) {
		i = barlength * ratio / 100;
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 "|%.*s%*s|", i,
			 "*****************************************************************************"
			 "*****************************************************************************",
			 barlength - i, "");
	}
	i = 0;
	abbrevsize = cursize;
	while (abbrevsize >= 100000 && i < sizeof(prefixes)) {
		i++;
		abbrevsize >>= 10;
	}
	snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " %5d %c%c ",
	     (int) abbrevsize, prefixes[i], prefixes[i] == ' ' ? ' ' :
		 'B');

	timersub(&now, &lastupdate, &wait);
	if (cursize > lastsize) {
		lastupdate = now;
		lastsize = cursize;
		if (wait.tv_sec >= STALLTIME) {
			start.tv_sec += wait.tv_sec;
			start.tv_usec += wait.tv_usec;
		}
		wait.tv_sec = 0;
	}
	timersub(&now, &start, &td);
	elapsed = td.tv_sec + (td.tv_usec / 1000000.0);

	if (statbytes <= 0 || elapsed <= 0.0 || cursize > filesize) {
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 "   --:-- ETA");
	} else if (wait.tv_sec >= STALLTIME) {
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 " - stalled -");
	} else {
		remaining = (int) (filesize / (statbytes / elapsed) - elapsed);
		i = remaining / 3600;
		if (i)
			snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
				 "%2d:", i);
		else
			snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
				 "   ");
		i = remaining % 3600;
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 "%02d:%02d ETA", i / 60, i % 60);
	}
	write(fileno(stderr), buf, strlen(buf));

	if (flag == -1) {
		struct sigaction sa;
		sa.sa_handler = updateprogressmeter;
		sigemptyset(&sa.sa_mask);
		sa.sa_flags = SA_RESTART;
		sigaction(SIGALRM, &sa, NULL);
		alarmtimer(1);
	} else if (flag == 1) {
		alarmtimer(0);
		statbytes = 0;
	}
}
#endif

/* Original copyright notice which applies to the BB_FEATURE_WGET_STATUSBAR stuff,
 * much of which was blatently stolen from openssh.  */
 
/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change 
 *		ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change> 
 *
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	$Id: wget.c,v 1.31 2001/04/05 21:45:53 andersen Exp $
 */


/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/