http_filters.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

            ctx->eos_sent = 1;
            return APR_SUCCESS;
        case BODY_CHUNK:
        case BODY_CHUNK_PART:
            {
                apr_brigade_cleanup(bb);

                /* We need to read the CRLF after the chunk.  */
                if (ctx->state == BODY_CHUNK) {
                    rv = ap_get_brigade(f->next, bb, AP_MODE_GETLINE,
                                        block, 0);
                    if (block == APR_NONBLOCK_READ &&
                        ( (rv == APR_SUCCESS && APR_BRIGADE_EMPTY(bb)) ||
                          (APR_STATUS_IS_EAGAIN(rv)) )) {
                        return APR_EAGAIN;
                    }
                    /* If we get an error, then leave */
                    if (rv != APR_SUCCESS) {
                        return rv;
                    }
                    /*
                     * We really don't care whats on this line. If it is RFC
                     * compliant it should be only \r\n. If there is more
                     * before we just ignore it as long as we do not get over
                     * the limit for request lines.
                     */
                    rv = get_remaining_chunk_line(ctx, bb,
                                                  f->r->server->limit_req_line);
                    apr_brigade_cleanup(bb);
                    if (APR_STATUS_IS_EAGAIN(rv)) {
                        return rv;
                    }
                } else {
                    rv = APR_SUCCESS;
                }

                if (rv == APR_SUCCESS) {
                    /* Read the real chunk line. */
                    rv = ap_get_brigade(f->next, bb, AP_MODE_GETLINE,
                                        block, 0);
                    /* Test timeout */
                    if (block == APR_NONBLOCK_READ &&
                        ( (rv == APR_SUCCESS && APR_BRIGADE_EMPTY(bb)) ||
                          (APR_STATUS_IS_EAGAIN(rv)) )) {
                        ctx->state = BODY_CHUNK_PART;
                        return APR_EAGAIN;
                    }
                    ctx->state = BODY_CHUNK;
                    if (rv == APR_SUCCESS) {
                        rv = get_chunk_line(ctx, bb, f->r->server->limit_req_line);
                        if (APR_STATUS_IS_EAGAIN(rv)) {
                            ctx->state = BODY_CHUNK_PART;
                            apr_brigade_cleanup(bb);
                            return rv;
                        }
                        if (rv == APR_SUCCESS) {
                            ctx->remaining = get_chunk_size(ctx->chunk_ln);
                            if (ctx->remaining == INVALID_CHAR) {
                                rv = APR_EGENERAL;
                                http_error = HTTP_SERVICE_UNAVAILABLE;
                            }
                        }
                    }
                    apr_brigade_cleanup(bb);
                }

                /* Detect chunksize error (such as overflow) */
                if (rv != APR_SUCCESS || ctx->remaining < 0) {
                    ctx->remaining = 0; /* Reset it in case we have to
                                         * come back here later */
                    bail_out_on_error(ctx, f, http_error);
                    return rv;
                }

                if (!ctx->remaining) {
                    /* Handle trailers by calling ap_get_mime_headers again! */
                    ctx->state = BODY_NONE;
                    ap_get_mime_headers(f->r);
                    e = apr_bucket_eos_create(f->c->bucket_alloc);
                    APR_BRIGADE_INSERT_TAIL(b, e);
                    ctx->eos_sent = 1;
                    return APR_SUCCESS;
                }
            }
            break;
        }
    }

    /* Ensure that the caller can not go over our boundary point. */
    if (ctx->state == BODY_LENGTH || ctx->state == BODY_CHUNK) {
        if (ctx->remaining < readbytes) {
            readbytes = ctx->remaining;
        }
        AP_DEBUG_ASSERT(readbytes > 0);
    }

    rv = ap_get_brigade(f->next, b, mode, block, readbytes);

    if (rv != APR_SUCCESS) {
        return rv;
    }

    /* How many bytes did we just read? */
    apr_brigade_length(b, 0, &totalread);

    /* If this happens, we have a bucket of unknown length.  Die because
     * it means our assumptions have changed. */
    AP_DEBUG_ASSERT(totalread >= 0);

    if (ctx->state != BODY_NONE) {
        ctx->remaining -= totalread;
    }

    /* If we have no more bytes remaining on a C-L request,
     * save the callter a roundtrip to discover EOS.
     */
    if (ctx->state == BODY_LENGTH && ctx->remaining == 0) {
        e = apr_bucket_eos_create(f->c->bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(b, e);
    }

    /* We have a limit in effect. */
    if (ctx->limit) {
        /* FIXME: Note that we might get slightly confused on chunked inputs
         * as we'd need to compensate for the chunk lengths which may not
         * really count.  This seems to be up for interpretation.  */
        ctx->limit_used += totalread;
        if (ctx->limit < ctx->limit_used) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, f->r,
                          "Read content-length of %" APR_OFF_T_FMT
                          " is larger than the configured limit"
                          " of %" APR_OFF_T_FMT, ctx->limit_used, ctx->limit);
            apr_brigade_cleanup(bb);
            e = ap_bucket_error_create(HTTP_REQUEST_ENTITY_TOO_LARGE, NULL,
                                       f->r->pool,
                                       f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(bb, e);
            e = apr_bucket_eos_create(f->c->bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(bb, e);
            ctx->eos_sent = 1;
            return ap_pass_brigade(f->r->output_filters, bb);
        }
    }

    return APR_SUCCESS;
}

/**
 * Parse a chunk extension, detect overflow.
 * There are two error cases:
 *  1) If the conversion would require too many bits, a -1 is returned.
 *  2) If the conversion used the correct number of bits, but an overflow
 *     caused only the sign bit to flip, then that negative number is
 *     returned.
 * In general, any negative number can be considered an overflow error.
 */
static long get_chunk_size(char *b)
{
    long chunksize = 0;
    size_t chunkbits = sizeof(long) * 8;

    ap_xlate_proto_from_ascii(b, strlen(b));

    if (!apr_isxdigit(*b)) {
        /*
         * Detect invalid character at beginning. This also works for empty
         * chunk size lines.
         */
        return INVALID_CHAR;
    }
    /* Skip leading zeros */
    while (*b == '0') {
        ++b;
    }

    while (apr_isxdigit(*b) && (chunkbits > 0)) {
        int xvalue = 0;

        if (*b >= '0' && *b <= '9') {
            xvalue = *b - '0';
        }
        else if (*b >= 'A' && *b <= 'F') {
            xvalue = *b - 'A' + 0xa;
        }
        else if (*b >= 'a' && *b <= 'f') {
            xvalue = *b - 'a' + 0xa;
        }

        chunksize = (chunksize << 4) | xvalue;
        chunkbits -= 4;
        ++b;
    }
    if (apr_isxdigit(*b) && (chunkbits <= 0)) {
        /* overflow */
        return -1;
    }

    return chunksize;
}

typedef struct header_struct {
    apr_pool_t *pool;
    apr_bucket_brigade *bb;
} header_struct;

/* Send a single HTTP header field to the client.  Note that this function
 * is used in calls to table_do(), so their interfaces are co-dependent.
 * In other words, don't change this one without checking table_do in alloc.c.
 * It returns true unless there was a write error of some kind.
 */
static int form_header_field(header_struct *h,
                             const char *fieldname, const char *fieldval)
{
#if APR_CHARSET_EBCDIC
    char *headfield;
    apr_size_t len;
    apr_size_t name_len;
    apr_size_t val_len;
    char *next;

    name_len = strlen(fieldname);
    val_len = strlen(fieldval);
    len = name_len + val_len + 4; /* 4 for ": " plus CRLF */
    headfield = (char *)apr_palloc(h->pool, len + 1);
    memcpy(headfield, fieldname, name_len);
    next = headfield + name_len;
    *next++ = ':';
    *next++ = ' ';
    memcpy(next, fieldval, val_len);
    next += val_len;
    *next++ = CR;
    *next++ = LF;
    *next = 0;
    ap_xlate_proto_to_ascii(headfield, len);
    apr_brigade_write(h->bb, NULL, NULL, headfield, len);
#else
    struct iovec vec[4];
    struct iovec *v = vec;
    v->iov_base = (void *)fieldname;
    v->iov_len = strlen(fieldname);
    v++;
    v->iov_base = ": ";
    v->iov_len = sizeof(": ") - 1;
    v++;
    v->iov_base = (void *)fieldval;
    v->iov_len = strlen(fieldval);
    v++;
    v->iov_base = CRLF;
    v->iov_len = sizeof(CRLF) - 1;
    apr_brigade_writev(h->bb, NULL, NULL, vec, 4);
#endif /* !APR_CHARSET_EBCDIC */
    return 1;
}

/* This routine is called by apr_table_do and merges all instances of
 * the passed field values into a single array that will be further
 * processed by some later routine.  Originally intended to help split
 * and recombine multiple Vary fields, though it is generic to any field
 * consisting of comma/space-separated tokens.
 */
static int uniq_field_values(void *d, const char *key, const char *val)
{
    apr_array_header_t *values;
    char *start;
    char *e;
    char **strpp;
    int  i;

    values = (apr_array_header_t *)d;

    e = apr_pstrdup(values->pool, val);

    do {
        /* Find a non-empty fieldname */

        while (*e == ',' || apr_isspace(*e)) {
            ++e;
        }
        if (*e == '\0') {
            break;
        }
        start = e;
        while (*e != '\0' && *e != ',' && !apr_isspace(*e)) {
            ++e;
        }
        if (*e != '\0') {
            *e++ = '\0';
        }

        /* Now add it to values if it isn't already represented.
         * Could be replaced by a ap_array_strcasecmp() if we had one.
         */
        for (i = 0, strpp = (char **) values->elts; i < values->nelts;
             ++i, ++strpp) {
            if (*strpp && strcasecmp(*strpp, start) == 0) {
                break;
            }
        }
        if (i == values->nelts) {  /* if not found */
            *(char **)apr_array_push(values) = start;
        }
    } while (*e != '\0');

    return 1;
}

/*
 * Since some clients choke violently on multiple Vary fields, or
 * Vary fields with duplicate tokens, combine any multiples and remove
 * any duplicates.
 */
static void fixup_vary(request_rec *r)
{
    apr_array_header_t *varies;

    varies = apr_array_make(r->pool, 5, sizeof(char *));

    /* Extract all Vary fields from the headers_out, separate each into
     * its comma-separated fieldname values, and then add them to varies
     * if not already present in the array.
     */
    apr_table_do((int (*)(void *, const char *, const char *))uniq_field_values,
                 (void *) varies, r->headers_out, "Vary", NULL);

    /* If we found any, replace old Vary fields with unique-ified value */

    if (varies->nelts > 0) {
        apr_table_setn(r->headers_out, "Vary",
                       apr_array_pstrcat(r->pool, varies, ','));
    }
}

/* Send a request's HTTP response headers to the client.
 */
static apr_status_t send_all_header_fields(header_struct *h,
                                           const request_rec *r)
{
    const apr_array_header_t *elts;
    const apr_table_entry_t *t_elt;
    const apr_table_entry_t *t_end;
    struct iovec *vec;
    struct iovec *vec_next;

    elts = apr_table_elts(r->headers_out);
    if (elts->nelts == 0) {
        return APR_SUCCESS;
    }
    t_elt = (const apr_table_entry_t *)(elts->elts);
    t_end = t_elt + elts->nelts;
    vec = (struct iovec *)apr_palloc(h->pool, 4 * elts->nelts *
                                     sizeof(struct iovec));
    vec_next = vec;

    /* For each field, generate
     *    name ": " value CRLF
     */
    do {
        vec_next->iov_base = (void*)(t_elt->key);
        vec_next->iov_len = strlen(t_elt->key);
        vec_next++;
        vec_next->iov_base = ": ";
        vec_next->iov_len = sizeof(": ") - 1;
        vec_next++;
        vec_next->iov_base = (void*)(t_elt->val);
        vec_next->iov_len = strlen(t_elt->val);
        vec_next++;
        vec_next->iov_base = CRLF;
        vec_next->iov_len = sizeof(CRLF) - 1;
        vec_next++;
        t_elt++;
    } while (t_elt < t_end);

#if APR_CHARSET_EBCDIC
    {
        apr_size_t len;
        char *tmp = apr_pstrcatv(r->pool, vec, vec_next - vec, &len);
        ap_xlate_proto_to_ascii(tmp, len);
        return apr_brigade_write(h->bb, NULL, NULL, tmp, len);
    }
#else
    return apr_brigade_writev(h->bb, NULL, NULL, vec, vec_next - vec);
#endif
}

/* Confirm that the status line is well-formed and matches r->status.
 * If they don't match, a filter may have negated the status line set by a
 * handler.
 * Zap r->status_line if bad.
 */
static void validate_status_line(request_rec *r)
{
    char *end;

    if (r->status_line
        && (strlen(r->status_line) <= 4
            || apr_strtoi64(r->status_line, &end, 10) != r->status
            || *end != ' '
            || (end - 3) != r->status_line)) {
        r->status_line = NULL;
    }
}

/*
 * Determine the protocol to use for the response. Potentially downgrade
 * to HTTP/1.0 in some situations and/or turn off keepalives.
 *
 * also prepare r->status_line.
 */
static void basic_http_header_check(request_rec *r,
                                    const char **protocol)
{
    if (r->assbackwards) {