wget.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

/* vi: set sw=4 ts=4: */
/*
 * wget - retrieve a file using HTTP or FTP
 *
 * Chip Rosenthal Covad Communications <[e-mail]>
 *
 */

#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>

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <getopt.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);

/* Globals (can be accessed from signal handlers */
static off_t filesize = 0;		/* content-length of the file */
static int chunked = 0;			/* chunked transfer encoding */
#ifdef CONFIG_FEATURE_WGET_STATUSBAR
static void progressmeter(int flag);
static char *curfile;			/* Name of current file being transferred. */
static struct timeval start;	/* Time a transfer started. */
static volatile unsigned long statbytes = 0; /* 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);
	}
}

/* Read NMEMB elements of SIZE bytes into PTR from STREAM.  Returns the
 * number of elements read, and a short count if an eof or non-interrupt
 * error is encountered.  */
static size_t safe_fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
{
	size_t ret = 0;

	do {
		clearerr(stream);
		ret += fread((char *)ptr + (ret * size), size, nmemb - ret, stream);
	} while (ret < nmemb && ferror(stream) && errno == EINTR);

	return ret;
}

/* Write NMEMB elements of SIZE bytes from PTR to STREAM.  Returns the
 * number of elements written, and a short count if an eof or non-interrupt
 * error is encountered.  */
static size_t safe_fwrite(void *ptr, size_t size, size_t nmemb, FILE *stream)
{
	size_t ret = 0;

	do {
		clearerr(stream);
		ret += fwrite((char *)ptr + (ret * size), size, nmemb - ret, stream);
	} while (ret < nmemb && ferror(stream) && errno == EINTR);

	return ret;
}

/* Read a line or SIZE - 1 bytes into S, whichever is less, from STREAM.
 * Returns S, or NULL if an eof or non-interrupt error is encountered.  */
static char *safe_fgets(char *s, int size, FILE *stream)
{
	char *ret;

	do {
		clearerr(stream);
		ret = fgets(s, size, stream);
	} while (ret == NULL && ferror(stream) && errno == EINTR);

	return ret;
}

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


#ifdef CONFIG_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 = 0;
	char *dir_prefix=NULL;
	char *s, buf[512];
	struct stat sbuf;
	char extra_headers[1024];
	char *extra_headers_ptr = extra_headers;
	int extra_headers_left = sizeof(extra_headers);
	int which_long_opt = 0, option_index = -1;
	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...			*/
	int noproxy = 0;            /* Use proxies if env vars are set  */

#define LONG_HEADER	1
	struct option long_options[] = {
		{ "continue",		0, NULL, 'c' },
		{ "quiet",		0, NULL, 'q' },
		{ "output-document",	1, NULL, 'O' },
		{ "header",		1, &which_long_opt, LONG_HEADER },
		{ "proxy",		1, NULL, 'Y' },
		{ 0,			0, 0, 0 }
	};
	/*
	 * Crack command line.
	 */
	while ((n = getopt_long(argc, argv, "cqO:P:Y:", long_options, &option_index)) != EOF) {
		switch (n) {
		case 'c':
			++do_continue;
			break;
		case 'P':
			dir_prefix = optarg;
			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  - [e-mail]
			 */
			fname_out = optarg;
			break;
		case 'Y':
			if (strcmp(optarg, "off") == 0)
				noproxy=1;	
			break;
		case 0:
			switch (which_long_opt) {
				case LONG_HEADER: {
					int arglen = strlen(optarg);
					if(extra_headers_left - arglen - 2 <= 0)
						error_msg_and_die("extra_headers buffer too small(need %i)", extra_headers_left - arglen);
					strcpy(extra_headers_ptr, optarg);
					extra_headers_ptr += arglen;
					extra_headers_left -= ( arglen + 2 );
					*extra_headers_ptr++ = '\r';
					*extra_headers_ptr++ = '\n';
					*(extra_headers_ptr + 1) = 0;
					break;
				}
			}
			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.
	 */
	if (!noproxy) {
		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 CONFIG_FEATURE_WGET_STATUSBAR
			curfile = 
#endif
			get_last_path_component(target.path);
		if (fname_out==NULL || strlen(fname_out)<1) {
			fname_out = 
#ifdef CONFIG_FEATURE_WGET_STATUSBAR
				curfile = 
#endif
				"index.html";
		}
		if (dir_prefix != NULL)
			fname_out = concat_path_file(dir_prefix, fname_out);
#ifdef CONFIG_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 (strcmp(fname_out, "-") == 0) {
		output = stdout;
		quiet_flag = TRUE;
	} else {
		output = xfopen(fname_out, (do_continue ? "a" : "w"));
	}

	/*
	 * 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/1.1\r\n",
					target.is_ftp ? "f" : "ht", target.host,
					target.port, target.path);
			} else {
				fprintf(sfp, "GET /%s HTTP/1.1\r\n", target.path);
			}

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

#ifdef CONFIG_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);
			if(extra_headers_left < sizeof(extra_headers))
				fputs(extra_headers,sfp);
			fprintf(sfp,"Connection: close\r\n\r\n");

			/*
		 	* Retrieve HTTP response line and check for "200" status code.
		 	*/
read_response:		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 100:
					while (gethdr(buf, sizeof(buf), sfp, &n) != NULL);
					goto read_response;
				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) {
					if (strcasecmp(s, "chunked") == 0) {
						chunked = got_clen = 1;
					} else {
					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);