freebsd-skq/lib/libfetch/http.c
Dag-Erling Smørgrav e4878e39a3 Extensive rewrite of the HTTP code. The new code is significantly cleaner and
more robust, and somewhat more efficient. It also handles authorization and
redirects properly, and supports timeouts like the FTP code.

Many thanks to Umemoto-san for his assistance with IPv6 support, both here
and in other parts of libfetch.
2000-07-12 10:39:56 +00:00

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/*-
* Copyright (c) 2000 Dag-Erling Coïdan Smørgrav
* 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
* in this position and unchanged.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <locale.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "fetch.h"
#include "common.h"
#include "httperr.h"
extern char *__progname; /* XXX not portable */
/* Maximum number of redirects to follow */
#define MAX_REDIRECT 5
/* Symbolic names for reply codes we care about */
#define HTTP_OK 200
#define HTTP_PARTIAL 206
#define HTTP_MOVED_PERM 301
#define HTTP_MOVED_TEMP 302
#define HTTP_SEE_OTHER 303
#define HTTP_NEED_AUTH 401
#define HTTP_NEED_PROXY_AUTH 403
#define HTTP_PROTOCOL_ERROR 999
#define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
|| (xyz) == HTTP_MOVED_TEMP \
|| (xyz) == HTTP_SEE_OTHER)
/*****************************************************************************
* I/O functions for decoding chunked streams
*/
struct cookie
{
int fd;
char *buf;
size_t b_size;
size_t b_len;
int b_pos;
int eof;
int error;
long chunksize;
#ifdef DEBUG
long total;
#endif
};
/*
* Get next chunk header
*/
static int
_http_new_chunk(struct cookie *c)
{
char *p;
if (_fetch_getln(c->fd, &c->buf, &c->b_size, &c->b_len) == -1)
return -1;
if (c->b_len < 2 || !ishexnumber(*c->buf))
return -1;
for (p = c->buf; !isspace(*p) && *p != ';' && p < c->buf + c->b_len; ++p)
if (!ishexnumber(*p))
return -1;
else if (isdigit(*p))
c->chunksize = c->chunksize * 16 + *p - '0';
else
c->chunksize = c->chunksize * 16 + 10 + tolower(*p) - 'a';
#ifdef DEBUG
c->total += c->chunksize;
if (c->chunksize == 0)
fprintf(stderr, "\033[1m_http_fillbuf(): "
"end of last chunk\033[m\n");
else
fprintf(stderr, "\033[1m_http_fillbuf(): "
"new chunk: %ld (%ld)\033[m\n", c->chunksize, c->total);
#endif
return c->chunksize;
}
/*
* Fill the input buffer, do chunk decoding on the fly
*/
static int
_http_fillbuf(struct cookie *c)
{
if (c->error)
return -1;
if (c->eof)
return 0;
if (c->chunksize == 0) {
switch (_http_new_chunk(c)) {
case -1:
c->error = 1;
return -1;
case 0:
c->eof = 1;
return 0;
}
}
if (c->b_size < c->chunksize) {
char *tmp;
if ((tmp = realloc(c->buf, c->chunksize)) == NULL)
return -1;
c->buf = tmp;
c->b_size = c->chunksize;
}
if ((c->b_len = read(c->fd, c->buf, c->chunksize)) == -1)
return -1;
c->chunksize -= c->b_len;
if (c->chunksize == 0) {
char endl[2];
read(c->fd, endl, 2);
}
c->b_pos = 0;
return c->b_len;
}
/*
* Read function
*/
static int
_http_readfn(void *v, char *buf, int len)
{
struct cookie *c = (struct cookie *)v;
int l, pos;
if (c->error)
return -1;
if (c->eof)
return 0;
for (pos = 0; len > 0; pos += l, len -= l) {
/* empty buffer */
if (!c->buf || c->b_pos == c->b_len)
if (_http_fillbuf(c) < 1)
break;
l = c->b_len - c->b_pos;
if (len < l)
l = len;
bcopy(c->buf + c->b_pos, buf + pos, l);
c->b_pos += l;
}
if (!pos && c->error)
return -1;
return pos;
}
/*
* Write function
*/
static int
_http_writefn(void *v, const char *buf, int len)
{
struct cookie *c = (struct cookie *)v;
return write(c->fd, buf, len);
}
/*
* Close function
*/
static int
_http_closefn(void *v)
{
struct cookie *c = (struct cookie *)v;
int r;
r = close(c->fd);
if (c->buf)
free(c->buf);
free(c);
return r;
}
/*
* Wrap a file descriptor up
*/
static FILE *
_http_funopen(int fd)
{
struct cookie *c;
FILE *f;
if ((c = calloc(1, sizeof *c)) == NULL) {
_fetch_syserr();
return NULL;
}
c->fd = fd;
if (!(f = funopen(c, _http_readfn, _http_writefn, NULL, _http_closefn))) {
_fetch_syserr();
free(c);
return NULL;
}
return f;
}
/*****************************************************************************
* Helper functions for talking to the server and parsing its replies
*/
/* Header types */
typedef enum {
hdr_syserror = -2,
hdr_error = -1,
hdr_end = 0,
hdr_unknown = 1,
hdr_content_length,
hdr_content_range,
hdr_last_modified,
hdr_location,
hdr_transfer_encoding
} hdr;
/* Names of interesting headers */
static struct {
hdr num;
char *name;
} hdr_names[] = {
{ hdr_content_length, "Content-Length" },
{ hdr_content_range, "Content-Range" },
{ hdr_last_modified, "Last-Modified" },
{ hdr_location, "Location" },
{ hdr_transfer_encoding, "Transfer-Encoding" },
{ hdr_unknown, NULL },
};
static char *reply_buf;
static size_t reply_size;
static size_t reply_length;
/*
* Send a formatted line; optionally echo to terminal
*/
static int
_http_cmd(int fd, char *fmt, ...)
{
va_list ap;
size_t len;
char *msg;
int r;
va_start(ap, fmt);
len = vasprintf(&msg, fmt, ap);
va_end(ap);
if (msg == NULL) {
errno = ENOMEM;
_fetch_syserr();
return -1;
}
r = _fetch_putln(fd, msg, len);
free(msg);
if (r == -1) {
_fetch_syserr();
return -1;
}
return 0;
}
/*
* Get and parse status line
*/
static int
_http_get_reply(int fd)
{
if (_fetch_getln(fd, &reply_buf, &reply_size, &reply_length) == -1)
return -1;
/*
* A valid status line looks like "HTTP/m.n xyz reason" where m
* and n are the major and minor protocol version numbers and xyz
* is the reply code.
* We grok HTTP 1.0 and 1.1, so m must be 1 and n must be 0 or 1.
* We don't care about the reason phrase.
*/
if (strncmp(reply_buf, "HTTP/1.", 7) != 0
|| (reply_buf[7] != '0' && reply_buf[7] != '1') || reply_buf[8] != ' '
|| !isdigit(reply_buf[9])
|| !isdigit(reply_buf[10])
|| !isdigit(reply_buf[11]))
return HTTP_PROTOCOL_ERROR;
return ((reply_buf[9] - '0') * 100
+ (reply_buf[10] - '0') * 10
+ (reply_buf[11] - '0'));
}
/*
* Check a header; if the type matches the given string, return a
* pointer to the beginning of the value.
*/
static char *
_http_match(char *str, char *hdr)
{
while (*str && *hdr && tolower(*str++) == tolower(*hdr++))
/* nothing */;
if (*str || *hdr != ':')
return NULL;
while (*hdr && isspace(*++hdr))
/* nothing */;
return hdr;
}
/*
* Get the next header and return the appropriate symbolic code.
*/
static hdr
_http_next_header(int fd, char **p)
{
int i;
if (_fetch_getln(fd, &reply_buf, &reply_size, &reply_length) == -1)
return hdr_syserror;
while (reply_length && isspace(reply_buf[reply_length-1]))
reply_length--;
reply_buf[reply_length] = 0;
if (reply_length == 0)
return hdr_end;
/*
* We could check for malformed headers but we don't really care.
* A valid header starts with a token immediately followed by a
* colon; a token is any sequence of non-control, non-whitespace
* characters except "()<>@,;:\\\"{}".
*/
for (i = 0; hdr_names[i].num != hdr_unknown; i++)
if ((*p = _http_match(hdr_names[i].name, reply_buf)) != NULL)
return hdr_names[i].num;
return hdr_unknown;
}
/*
* Parse a last-modified header
*/
static time_t
_http_parse_mtime(char *p)
{
char locale[64];
struct tm tm;
strncpy(locale, setlocale(LC_TIME, NULL), sizeof locale);
setlocale(LC_TIME, "C");
strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
/* XXX should add support for date-2 and date-3 */
setlocale(LC_TIME, locale);
DEBUG(fprintf(stderr, "last modified: [\033[1m%04d-%02d-%02d "
"%02d:%02d:%02d\033[m]\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min, tm.tm_sec));
return timegm(&tm);
}
/*
* Parse a content-length header
*/
static off_t
_http_parse_length(char *p)
{
off_t len;
for (len = 0; *p && isdigit(*p); ++p)
len = len * 10 + (*p - '0');
DEBUG(fprintf(stderr, "content length: [\033[1m%lld\033[m]\n", len));
return len;
}
/*
* Parse a content-range header
*/
static off_t
_http_parse_range(char *p)
{
off_t off;
if (strncasecmp(p, "bytes ", 6) != 0)
return -1;
for (p += 6, off = 0; *p && isdigit(*p); ++p)
off = off * 10 + *p - '0';
if (*p != '-')
return -1;
DEBUG(fprintf(stderr, "content range: [\033[1m%lld-\033[m]\n", off));
return off;
}
/*****************************************************************************
* Helper functions for authorization
*/
/*
* Base64 encoding
*/
static char *
_http_base64(char *src)
{
static const char base64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
char *str, *dst;
size_t l;
int t, r;
l = strlen(src);
if ((str = malloc(((l + 2) / 3) * 4)) == NULL)
return NULL;
dst = str;
r = 0;
while (l >= 3) {
t = (src[0] << 16) | (src[1] << 8) | src[2];
dst[0] = base64[(t >> 18) & 0x3f];
dst[1] = base64[(t >> 12) & 0x3f];
dst[2] = base64[(t >> 6) & 0x3f];
dst[3] = base64[(t >> 0) & 0x3f];
src += 3; l -= 3;
dst += 4; r += 4;
}
switch (l) {
case 2:
t = (src[0] << 16) | (src[1] << 8);
dst[0] = base64[(t >> 18) & 0x3f];
dst[1] = base64[(t >> 12) & 0x3f];
dst[2] = base64[(t >> 6) & 0x3f];
dst[3] = '=';
dst += 4;
r += 4;
break;
case 1:
t = src[0] << 16;
dst[0] = base64[(t >> 18) & 0x3f];
dst[1] = base64[(t >> 12) & 0x3f];
dst[2] = dst[3] = '=';
dst += 4;
r += 4;
break;
case 0:
break;
}
*dst = 0;
return str;
}
/*
* Encode username and password
*/
static int
_http_basic_auth(int fd, char *hdr, char *usr, char *pwd)
{
char *upw, *auth;
int r;
if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
return -1;
auth = _http_base64(upw);
free(upw);
if (auth == NULL)
return -1;
r = _http_cmd(fd, "%s: Basic %s", hdr, auth);
free(auth);
return r;
}
/*
* Send an authorization header
*/
static int
_http_authorize(int fd, char *hdr, char *p)
{
/* basic authorization */
if (strncasecmp(p, "basic:", 6) == 0) {
char *user, *pwd, *str;
int r;
/* skip realm */
for (p += 6; *p && *p != ':'; ++p)
/* nothing */ ;
if (!*p || strchr(++p, ':') == NULL)
return -1;
if ((str = strdup(p)) == NULL)
return -1; /* XXX */
user = str;
pwd = strchr(str, ':');
*pwd++ = '\0';
r = _http_basic_auth(fd, hdr, user, pwd);
free(str);
return r;
}
return -1;
}
/*****************************************************************************
* Helper functions for connecting to a server or proxy
*/
/*
* Connect to the specified HTTP proxy server.
*/
static int
_http_proxy_connect(char *proxy, int af, int verbose)
{
char *hostname, *p;
int fd, port;
/* get hostname */
hostname = NULL;
#ifdef INET6
/* host part can be an IPv6 address enclosed in square brackets */
if (*proxy == '[') {
if ((p = strchr(proxy, ']')) == NULL) {
/* no terminating bracket */
/* XXX should set an error code */
goto ouch;
}
if (p[1] != '\0' && p[1] != ':') {
/* garbage after address */
/* XXX should set an error code */
goto ouch;
}
if ((hostname = malloc(p - proxy)) == NULL) {
errno = ENOMEM;
_fetch_syserr();
goto ouch;
}
strncpy(hostname, proxy + 1, p - proxy - 1);
hostname[p - proxy - 1] = '\0';
++p;
} else {
#endif /* INET6 */
if ((p = strchr(proxy, ':')) == NULL)
p = strchr(proxy, '\0');
if ((hostname = malloc(p - proxy + 1)) == NULL) {
errno = ENOMEM;
_fetch_syserr();
goto ouch;
}
strncpy(hostname, proxy, p - proxy);
hostname[p - proxy] = '\0';
#ifdef INET6
}
#endif /* INET6 */
DEBUG(fprintf(stderr, "proxy name: [%s]\n", hostname));
/* get port number */
port = 0;
if (*p == ':') {
++p;
if (strspn(p, "0123456789") != strlen(p) || strlen(p) > 5) {
/* port number is non-numeric or too long */
/* XXX should set an error code */
goto ouch;
}
port = atoi(p);
if (port < 1 || port > 65535) {
/* port number is out of range */
/* XXX should set an error code */
goto ouch;
}
}
if (!port) {
#if 0
/*
* commented out, since there is currently no service name
* for HTTP proxies
*/
struct servent *se;
if ((se = getservbyname("xxxx", "tcp")) != NULL)
port = ntohs(se->s_port);
else
#endif
port = 3128;
}
DEBUG(fprintf(stderr, "proxy port: %d\n", port));
/* connect */
if ((fd = _fetch_connect(hostname, port, af, verbose)) == -1)
_fetch_syserr();
return fd;
ouch:
if (hostname)
free(hostname);
return -1;
}
/*
* Connect to the correct HTTP server or proxy.
*/
static int
_http_connect(struct url *URL, int *proxy, char *flags)
{
int direct, verbose;
int af, fd;
char *p;
#ifdef INET6
af = AF_UNSPEC;
#else
af = AF_INET;
#endif
direct = (flags && strchr(flags, 'd'));
verbose = (flags && strchr(flags, 'v'));
if (flags && strchr(flags, '4'))
af = AF_INET;
else if (flags && strchr(flags, '6'))
af = AF_INET6;
/* check port */
if (!URL->port) {
struct servent *se;
/* Scheme can be ftp if we're using a proxy */
if (strcasecmp(URL->scheme, "ftp") == 0)
if ((se = getservbyname("ftp", "tcp")) != NULL)
URL->port = ntohs(se->s_port);
else
URL->port = 21;
else
if ((se = getservbyname("http", "tcp")) != NULL)
URL->port = ntohs(se->s_port);
else
URL->port = 80;
}
if (!direct && (p = getenv("HTTP_PROXY")) != NULL) {
/* attempt to connect to proxy server */
if ((fd = _http_proxy_connect(p, af, verbose)) == -1)
return -1;
*proxy = 1;
} else {
/* if no proxy is configured, try direct */
if (strcasecmp(URL->scheme, "ftp") == 0) {
/* can't talk http to an ftp server */
/* XXX should set an error code */
return -1;
}
if ((fd = _fetch_connect(URL->host, URL->port, af, verbose)) == -1)
/* _fetch_connect() has already set an error code */
return -1;
*proxy = 0;
}
return fd;
}
/*****************************************************************************
* Core
*/
/*
* Send a request and process the reply
*/
static FILE *
_http_request(struct url *URL, char *op, struct url_stat *us, char *flags)
{
struct url *url, *new;
int chunked, need_auth, noredirect, proxy, verbose;
int code, fd, i, n;
off_t offset;
char *p;
FILE *f;
hdr h;
char *host;
#ifdef INET6
char hbuf[MAXHOSTNAMELEN + 1];
#endif
noredirect = (flags && strchr(flags, 'A'));
verbose = (flags && strchr(flags, 'v'));
n = noredirect ? 1 : MAX_REDIRECT;
us->size = -1;
us->atime = us->mtime = 0;
chunked = 0;
offset = 0;
fd = -1;
code = HTTP_PROTOCOL_ERROR; /* just to appease a compiler warning */
for (url = URL, i = 0; i < n; ++i) {
need_auth = 0;
retry:
/* connect to server or proxy */
if ((fd = _http_connect(url, &proxy, flags)) == -1)
goto ouch;
host = url->host;
#ifdef INET6
if (strchr(url->host, ':')) {
snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
host = hbuf;
}
#endif
/* send request */
if (verbose)
_fetch_info("requesting %s://%s:%d%s",
url->scheme, host, url->port, url->doc);
if (proxy) {
_http_cmd(fd, "%s %s://%s:%d%s HTTP/1.1",
op, url->scheme, host, url->port, url->doc);
} else {
_http_cmd(fd, "%s %s HTTP/1.1",
op, url->doc);
}
/* proxy authorization */
if (proxy && (p = getenv("HTTP_PROXY_AUTH")) != NULL)
_http_authorize(fd, "Proxy-Authorization", p);
/* server authorization */
if (need_auth) {
if (*url->user || *url->pwd)
_http_basic_auth(fd, "Authorization",
url->user ? url->user : "",
url->pwd ? url->pwd : "");
else if ((p = getenv("HTTP_AUTH")) != NULL)
_http_authorize(fd, "Authorization", p);
else {
_http_seterr(HTTP_NEED_AUTH);
goto ouch;
}
}
/* other headers */
_http_cmd(fd, "Host: %s:%d", host, url->port);
_http_cmd(fd, "User-Agent: %s " _LIBFETCH_VER, __progname);
if (URL->offset)
_http_cmd(fd, "Range: bytes=%lld-", url->offset);
_http_cmd(fd, "Connection: close");
_http_cmd(fd, "");
/* get reply */
switch ((code = _http_get_reply(fd))) {
case HTTP_OK:
case HTTP_PARTIAL:
/* fine */
break;
case HTTP_MOVED_PERM:
case HTTP_MOVED_TEMP:
/*
* Not so fine, but we still have to read the headers to
* get the new location.
*/
break;
case HTTP_NEED_AUTH:
if (need_auth) {
/*
* We already sent out authorization code, so there's
* nothing more we can do.
*/
_http_seterr(code);
goto ouch;
}
/* try again, but send the password this time */
if (verbose)
_fetch_info("server requires authorization");
need_auth = 1;
close(fd);
goto retry;
case HTTP_NEED_PROXY_AUTH:
/*
* If we're talking to a proxy, we already sent our proxy
* authorization code, so there's nothing more we can do.
*/
_http_seterr(code);
goto ouch;
case HTTP_PROTOCOL_ERROR:
/* fall through */
case -1:
_fetch_syserr();
goto ouch;
default:
_http_seterr(code);
goto ouch;
}
/* get headers */
do {
switch ((h = _http_next_header(fd, &p))) {
case hdr_syserror:
_fetch_syserr();
goto ouch;
case hdr_error:
_http_seterr(HTTP_PROTOCOL_ERROR);
goto ouch;
case hdr_content_length:
us->size = _http_parse_length(p);
break;
case hdr_content_range:
offset = _http_parse_range(p);
break;
case hdr_last_modified:
us->atime = us->mtime = _http_parse_mtime(p);
break;
case hdr_location:
if (!HTTP_REDIRECT(code))
break;
if (verbose)
_fetch_info("%d redirect to %s", code, p);
if ((new = fetchParseURL(p)) == NULL)
/* invalid location */
goto ouch;
if (!*new->user && !*new->pwd) {
strcpy(new->user, url->user);
strcpy(new->pwd, url->pwd);
}
new->offset = url->offset;
new->length = url->length;
close(fd);
us->size = -1;
us->atime = us->mtime = 0;
chunked = 0;
offset = 0;
fd = -1;
if (url != URL)
fetchFreeURL(url);
url = new;
continue;
case hdr_transfer_encoding:
/* XXX weak test*/
chunked = (strcasecmp(p, "chunked") == 0);
break;
case hdr_end:
/* fall through */
case hdr_unknown:
/* ignore */
break;
}
} while (h > hdr_end);
if (code == HTTP_OK || code == HTTP_PARTIAL)
break;
}
/* no success */
if (fd == -1) {
_http_seterr(code);
goto ouch;
}
/* wrap it up in a FILE */
if ((f = chunked ? _http_funopen(fd) : fdopen(fd, "r")) == NULL) {
_fetch_syserr();
goto ouch;
}
while (offset++ < url->offset)
if (fgetc(f) == EOF) {
_fetch_syserr();
fclose(f);
f = NULL;
}
if (url != URL)
fetchFreeURL(url);
return f;
ouch:
if (url != URL)
fetchFreeURL(url);
if (fd != -1)
close(fd);
return NULL;
}
/*****************************************************************************
* Entry points
*/
/*
* Retrieve a file by HTTP
*/
FILE *
fetchGetHTTP(struct url *URL, char *flags)
{
struct url_stat us;
return _http_request(URL, "GET", &us, flags);
}
FILE *
fetchPutHTTP(struct url *URL, char *flags)
{
warnx("fetchPutHTTP(): not implemented");
return NULL;
}
/*
* Get an HTTP document's metadata
*/
int
fetchStatHTTP(struct url *URL, struct url_stat *us, char *flags)
{
FILE *f;
if ((f = _http_request(URL, "HEAD", us, flags)) == NULL)
return -1;
fclose(f);
return 0;
}
/*
* List a directory
*/
struct url_ent *
fetchListHTTP(struct url *url, char *flags)
{
warnx("fetchListHTTP(): not implemented");
return NULL;
}