view src/http/modules/ngx_http_slice_filter_module.c @ 7508:c30a20e06c21

Range filter: fixed duplicate last buffers. In ngx_http_range_singlepart_body() special buffers where passed unmodified, including ones after the end of the range. As such, if the last buffer of a response was sent separately as a special buffer, two buffers with b->last_buf set were present in the response. In particular, this might result in a duplicate final chunk when using chunked transfer encoding (normally range filter and chunked transfer encoding are not used together, but this may happen if there are trailers in the response). This also likely to cause problems in HTTP/2. Fix is to skip all special buffers after we've sent the last part of the range requested. These special buffers are not meaningful anyway, since we set b->last_buf in the buffer with the last part of the range, and everything is expected to be flushed due to it. Additionally, ngx_http_next_body_filter() is now called even if no buffers are to be passed to it. This ensures that various write events are properly propagated through the filter chain. In particular, this fixes test failures observed with the above change and aio enabled.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 13 May 2019 22:44:49 +0300
parents f583559aadc7
children 32a343635b50
line wrap: on
line source


/*
 * Copyright (C) Roman Arutyunyan
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct {
    size_t               size;
} ngx_http_slice_loc_conf_t;


typedef struct {
    off_t                start;
    off_t                end;
    ngx_str_t            range;
    ngx_str_t            etag;
    unsigned             last:1;
    unsigned             active:1;
    ngx_http_request_t  *sr;
} ngx_http_slice_ctx_t;


typedef struct {
    off_t                start;
    off_t                end;
    off_t                complete_length;
} ngx_http_slice_content_range_t;


static ngx_int_t ngx_http_slice_header_filter(ngx_http_request_t *r);
static ngx_int_t ngx_http_slice_body_filter(ngx_http_request_t *r,
    ngx_chain_t *in);
static ngx_int_t ngx_http_slice_parse_content_range(ngx_http_request_t *r,
    ngx_http_slice_content_range_t *cr);
static ngx_int_t ngx_http_slice_range_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static off_t ngx_http_slice_get_start(ngx_http_request_t *r);
static void *ngx_http_slice_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent,
    void *child);
static ngx_int_t ngx_http_slice_add_variables(ngx_conf_t *cf);
static ngx_int_t ngx_http_slice_init(ngx_conf_t *cf);


static ngx_command_t  ngx_http_slice_filter_commands[] = {

    { ngx_string("slice"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_slice_loc_conf_t, size),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_slice_filter_module_ctx = {
    ngx_http_slice_add_variables,          /* preconfiguration */
    ngx_http_slice_init,                   /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_slice_create_loc_conf,        /* create location configuration */
    ngx_http_slice_merge_loc_conf          /* merge location configuration */
};


ngx_module_t  ngx_http_slice_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_slice_filter_module_ctx,     /* module context */
    ngx_http_slice_filter_commands,        /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_str_t  ngx_http_slice_range_name = ngx_string("slice_range");

static ngx_http_output_header_filter_pt  ngx_http_next_header_filter;
static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;


static ngx_int_t
ngx_http_slice_header_filter(ngx_http_request_t *r)
{
    off_t                            end;
    ngx_int_t                        rc;
    ngx_table_elt_t                 *h;
    ngx_http_slice_ctx_t            *ctx;
    ngx_http_slice_loc_conf_t       *slcf;
    ngx_http_slice_content_range_t   cr;

    ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module);
    if (ctx == NULL) {
        return ngx_http_next_header_filter(r);
    }

    if (r->headers_out.status != NGX_HTTP_PARTIAL_CONTENT) {
        if (r == r->main) {
            ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module);
            return ngx_http_next_header_filter(r);
        }

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "unexpected status code %ui in slice response",
                      r->headers_out.status);
        return NGX_ERROR;
    }

    h = r->headers_out.etag;

    if (ctx->etag.len) {
        if (h == NULL
            || h->value.len != ctx->etag.len
            || ngx_strncmp(h->value.data, ctx->etag.data, ctx->etag.len)
               != 0)
        {
            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                          "etag mismatch in slice response");
            return NGX_ERROR;
        }
    }

    if (h) {
        ctx->etag = h->value;
    }

    if (ngx_http_slice_parse_content_range(r, &cr) != NGX_OK) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "invalid range in slice response");
        return NGX_ERROR;
    }

    if (cr.complete_length == -1) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "no complete length in slice response");
        return NGX_ERROR;
    }

    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http slice response range: %O-%O/%O",
                   cr.start, cr.end, cr.complete_length);

    slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module);

    end = ngx_min(cr.start + (off_t) slcf->size, cr.complete_length);

    if (cr.start != ctx->start || cr.end != end) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "unexpected range in slice response: %O-%O",
                      cr.start, cr.end);
        return NGX_ERROR;
    }

    ctx->start = end;
    ctx->active = 1;

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.status_line.len = 0;
    r->headers_out.content_length_n = cr.complete_length;
    r->headers_out.content_offset = cr.start;
    r->headers_out.content_range->hash = 0;
    r->headers_out.content_range = NULL;

    r->allow_ranges = 1;
    r->subrequest_ranges = 1;
    r->single_range = 1;

    rc = ngx_http_next_header_filter(r);

    if (r != r->main) {
        return rc;
    }

    r->preserve_body = 1;

    if (r->headers_out.status == NGX_HTTP_PARTIAL_CONTENT) {
        if (ctx->start + (off_t) slcf->size <= r->headers_out.content_offset) {
            ctx->start = slcf->size
                         * (r->headers_out.content_offset / slcf->size);
        }

        ctx->end = r->headers_out.content_offset
                   + r->headers_out.content_length_n;

    } else {
        ctx->end = cr.complete_length;
    }

    return rc;
}


static ngx_int_t
ngx_http_slice_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
    ngx_int_t                   rc;
    ngx_chain_t                *cl;
    ngx_http_slice_ctx_t       *ctx;
    ngx_http_slice_loc_conf_t  *slcf;

    ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module);

    if (ctx == NULL || r != r->main) {
        return ngx_http_next_body_filter(r, in);
    }

    for (cl = in; cl; cl = cl->next) {
        if (cl->buf->last_buf) {
            cl->buf->last_buf = 0;
            cl->buf->last_in_chain = 1;
            cl->buf->sync = 1;
            ctx->last = 1;
        }
    }

    rc = ngx_http_next_body_filter(r, in);

    if (rc == NGX_ERROR || !ctx->last) {
        return rc;
    }

    if (ctx->sr && !ctx->sr->done) {
        return rc;
    }

    if (!ctx->active) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "missing slice response");
        return NGX_ERROR;
    }

    if (ctx->start >= ctx->end) {
        ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module);
        ngx_http_send_special(r, NGX_HTTP_LAST);
        return rc;
    }

    if (r->buffered) {
        return rc;
    }

    if (ngx_http_subrequest(r, &r->uri, &r->args, &ctx->sr, NULL,
                            NGX_HTTP_SUBREQUEST_CLONE)
        != NGX_OK)
    {
        return NGX_ERROR;
    }

    ngx_http_set_ctx(ctx->sr, ctx, ngx_http_slice_filter_module);

    slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module);

    ctx->range.len = ngx_sprintf(ctx->range.data, "bytes=%O-%O", ctx->start,
                                 ctx->start + (off_t) slcf->size - 1)
                     - ctx->range.data;

    ctx->active = 0;

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http slice subrequest: \"%V\"", &ctx->range);

    return rc;
}


static ngx_int_t
ngx_http_slice_parse_content_range(ngx_http_request_t *r,
    ngx_http_slice_content_range_t *cr)
{
    off_t             start, end, complete_length, cutoff, cutlim;
    u_char           *p;
    ngx_table_elt_t  *h;

    h = r->headers_out.content_range;

    if (h == NULL
        || h->value.len < 7
        || ngx_strncmp(h->value.data, "bytes ", 6) != 0)
    {
        return NGX_ERROR;
    }

    p = h->value.data + 6;

    cutoff = NGX_MAX_OFF_T_VALUE / 10;
    cutlim = NGX_MAX_OFF_T_VALUE % 10;

    start = 0;
    end = 0;
    complete_length = 0;

    while (*p == ' ') { p++; }

    if (*p < '0' || *p > '9') {
        return NGX_ERROR;
    }

    while (*p >= '0' && *p <= '9') {
        if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) {
            return NGX_ERROR;
        }

        start = start * 10 + (*p++ - '0');
    }

    while (*p == ' ') { p++; }

    if (*p++ != '-') {
        return NGX_ERROR;
    }

    while (*p == ' ') { p++; }

    if (*p < '0' || *p > '9') {
        return NGX_ERROR;
    }

    while (*p >= '0' && *p <= '9') {
        if (end >= cutoff && (end > cutoff || *p - '0' > cutlim)) {
            return NGX_ERROR;
        }

        end = end * 10 + (*p++ - '0');
    }

    end++;

    while (*p == ' ') { p++; }

    if (*p++ != '/') {
        return NGX_ERROR;
    }

    while (*p == ' ') { p++; }

    if (*p != '*') {
        if (*p < '0' || *p > '9') {
            return NGX_ERROR;
        }

        while (*p >= '0' && *p <= '9') {
            if (complete_length >= cutoff
                && (complete_length > cutoff || *p - '0' > cutlim))
            {
                return NGX_ERROR;
            }

            complete_length = complete_length * 10 + (*p++ - '0');
        }

    } else {
        complete_length = -1;
        p++;
    }

    while (*p == ' ') { p++; }

    if (*p != '\0') {
        return NGX_ERROR;
    }

    cr->start = start;
    cr->end = end;
    cr->complete_length = complete_length;

    return NGX_OK;
}


static ngx_int_t
ngx_http_slice_range_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    u_char                     *p;
    ngx_http_slice_ctx_t       *ctx;
    ngx_http_slice_loc_conf_t  *slcf;

    ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module);

    if (ctx == NULL) {
        if (r != r->main || r->headers_out.status) {
            v->not_found = 1;
            return NGX_OK;
        }

        slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module);

        if (slcf->size == 0) {
            v->not_found = 1;
            return NGX_OK;
        }

        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_slice_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_slice_filter_module);

        p = ngx_pnalloc(r->pool, sizeof("bytes=-") - 1 + 2 * NGX_OFF_T_LEN);
        if (p == NULL) {
            return NGX_ERROR;
        }

        ctx->start = slcf->size * (ngx_http_slice_get_start(r) / slcf->size);

        ctx->range.data = p;
        ctx->range.len = ngx_sprintf(p, "bytes=%O-%O", ctx->start,
                                     ctx->start + (off_t) slcf->size - 1)
                         - p;
    }

    v->data = ctx->range.data;
    v->valid = 1;
    v->not_found = 0;
    v->no_cacheable = 1;
    v->len = ctx->range.len;

    return NGX_OK;
}


static off_t
ngx_http_slice_get_start(ngx_http_request_t *r)
{
    off_t             start, cutoff, cutlim;
    u_char           *p;
    ngx_table_elt_t  *h;

    if (r->headers_in.if_range) {
        return 0;
    }

    h = r->headers_in.range;

    if (h == NULL
        || h->value.len < 7
        || ngx_strncasecmp(h->value.data, (u_char *) "bytes=", 6) != 0)
    {
        return 0;
    }

    p = h->value.data + 6;

    if (ngx_strchr(p, ',')) {
        return 0;
    }

    while (*p == ' ') { p++; }

    if (*p == '-') {
        return 0;
    }

    cutoff = NGX_MAX_OFF_T_VALUE / 10;
    cutlim = NGX_MAX_OFF_T_VALUE % 10;

    start = 0;

    while (*p >= '0' && *p <= '9') {
        if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) {
            return 0;
        }

        start = start * 10 + (*p++ - '0');
    }

    return start;
}


static void *
ngx_http_slice_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_slice_loc_conf_t  *slcf;

    slcf = ngx_palloc(cf->pool, sizeof(ngx_http_slice_loc_conf_t));
    if (slcf == NULL) {
        return NULL;
    }

    slcf->size = NGX_CONF_UNSET_SIZE;

    return slcf;
}


static char *
ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_slice_loc_conf_t *prev = parent;
    ngx_http_slice_loc_conf_t *conf = child;

    ngx_conf_merge_size_value(conf->size, prev->size, 0);

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_slice_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var;

    var = ngx_http_add_variable(cf, &ngx_http_slice_range_name, 0);
    if (var == NULL) {
        return NGX_ERROR;
    }

    var->get_handler = ngx_http_slice_range_variable;

    return NGX_OK;
}


static ngx_int_t
ngx_http_slice_init(ngx_conf_t *cf)
{
    ngx_http_next_header_filter = ngx_http_top_header_filter;
    ngx_http_top_header_filter = ngx_http_slice_header_filter;

    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_slice_body_filter;

    return NGX_OK;
}