/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/

#include "curl_setup.h"

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#ifdef HAVE_LINUX_TCP_H
#include <linux/tcp.h>
#elif defined(HAVE_NETINET_TCP_H)
#include <netinet/tcp.h>
#endif

#include <curl/curl.h>

#include "urldata.h"
#include "sendf.h"
#include "cfilters.h"
#include "connect.h"
#include "content_encoding.h"
#include "cw-out.h"
#include "vtls/vtls.h"
#include "vssh/ssh.h"
#include "easyif.h"
#include "multiif.h"
#include "strerror.h"
#include "select.h"
#include "strdup.h"
#include "http2.h"
#include "progress.h"
#include "ws.h"

/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"


static CURLcode do_init_stack(struct Curl_easy *data);

/* Curl_client_write() sends data to the write callback(s)

   The bit pattern defines to what "streams" to write to. Body and/or header.
   The defines are in sendf.h of course.
 */
CURLcode Curl_client_write(struct Curl_easy *data,
                           int type, const char *buf, size_t blen)
{
  CURLcode result;

  /* it is one of those, at least */
  DEBUGASSERT(type & (CLIENTWRITE_BODY|CLIENTWRITE_HEADER|CLIENTWRITE_INFO));
  /* BODY is only BODY (with optional EOS) */
  DEBUGASSERT(!(type & CLIENTWRITE_BODY) ||
              ((type & ~(CLIENTWRITE_BODY|CLIENTWRITE_EOS)) == 0));
  /* INFO is only INFO (with optional EOS) */
  DEBUGASSERT(!(type & CLIENTWRITE_INFO) ||
              ((type & ~(CLIENTWRITE_INFO|CLIENTWRITE_EOS)) == 0));

  if(!data->req.writer_stack) {
    result = do_init_stack(data);
    if(result)
      return result;
    DEBUGASSERT(data->req.writer_stack);
  }

  return Curl_cwriter_write(data, data->req.writer_stack, type, buf, blen);
}

void Curl_cw_reset(struct Curl_easy *data)
{
  struct Curl_cwriter *writer = data->req.writer_stack;

  while(writer) {
    data->req.writer_stack = writer->next;
    writer->cwt->do_close(data, writer);
    free(writer);
    writer = data->req.writer_stack;
  }

  data->req.bytecount = 0;
  data->req.headerline = 0;
}

/* Write data using an unencoding writer stack. "nbytes" is not
   allowed to be 0. */
CURLcode Curl_cwriter_write(struct Curl_easy *data,
                             struct Curl_cwriter *writer, int type,
                             const char *buf, size_t nbytes)
{
  if(!writer)
    return CURLE_WRITE_ERROR;
  return writer->cwt->do_write(data, writer, type, buf, nbytes);
}

CURLcode Curl_cwriter_def_init(struct Curl_easy *data,
                               struct Curl_cwriter *writer)
{
  (void)data;
  (void)writer;
  return CURLE_OK;
}

CURLcode Curl_cwriter_def_write(struct Curl_easy *data,
                                struct Curl_cwriter *writer, int type,
                                const char *buf, size_t nbytes)
{
  return Curl_cwriter_write(data, writer->next, type, buf, nbytes);
}

void Curl_cwriter_def_close(struct Curl_easy *data,
                            struct Curl_cwriter *writer)
{
  (void) data;
  (void) writer;
}

static size_t get_max_body_write_len(struct Curl_easy *data, curl_off_t limit)
{
  if(limit != -1) {
    /* How much more are we allowed to write? */
    curl_off_t remain_diff;
    remain_diff = limit - data->req.bytecount;
    if(remain_diff < 0) {
      /* already written too much! */
      return 0;
    }
#if SIZEOF_CURL_OFF_T > SIZEOF_SIZE_T
    else if(remain_diff > SSIZE_T_MAX) {
      return SIZE_T_MAX;
    }
#endif
    else {
      return (size_t)remain_diff;
    }
  }
  return SIZE_T_MAX;
}

/* Download client writer in phase CURL_CW_PROTOCOL that
 * sees the "real" download body data. */
static CURLcode cw_download_write(struct Curl_easy *data,
                                  struct Curl_cwriter *writer, int type,
                                  const char *buf, size_t nbytes)
{
  CURLcode result;
  size_t nwrite, excess_len = 0;

  if(!(type & CLIENTWRITE_BODY)) {
    if((type & CLIENTWRITE_CONNECT) && data->set.suppress_connect_headers)
      return CURLE_OK;
    return Curl_cwriter_write(data, writer->next, type, buf, nbytes);
  }

  if(!data->req.bytecount) {
    Curl_pgrsTime(data, TIMER_STARTTRANSFER);
    if(data->req.exp100 > EXP100_SEND_DATA)
      /* set time stamp to compare with when waiting for the 100 */
      data->req.start100 = Curl_now();
  }

  /* Here, we deal with REAL BODY bytes. All filtering and transfer
   * encodings have been applied and only the true content, e.g. BODY,
   * bytes are passed here.
   * This allows us to check sizes, update stats, etc. independent
   * from the protocol in play. */

  if(data->req.no_body && nbytes > 0) {
    /* BODY arrives although we want none, bail out */
    streamclose(data->conn, "ignoring body");
    DEBUGF(infof(data, "did not want a BODY, but seeing %zu bytes",
                 nbytes));
    data->req.download_done = TRUE;
    if(data->info.header_size)
      /* if headers have been received, this is fine */
      return CURLE_OK;
    return CURLE_WEIRD_SERVER_REPLY;
  }

  /* Determine if we see any bytes in excess to what is allowed.
   * We write the allowed bytes and handle excess further below.
   * This gives deterministic BODY writes on varying buffer receive
   * lengths. */
  nwrite = nbytes;
  if(-1 != data->req.maxdownload) {
    size_t wmax = get_max_body_write_len(data, data->req.maxdownload);
    if(nwrite > wmax) {
      excess_len = nbytes - wmax;
      nwrite = wmax;
    }

    if(nwrite == wmax) {
      data->req.download_done = TRUE;
    }
  }

  /* Error on too large filesize is handled below, after writing
   * the permitted bytes */
  if(data->set.max_filesize) {
    size_t wmax = get_max_body_write_len(data, data->set.max_filesize);
    if(nwrite > wmax) {
      nwrite = wmax;
    }
  }

  if(!data->req.ignorebody && (nwrite || (type & CLIENTWRITE_EOS))) {
    result = Curl_cwriter_write(data, writer->next, type, buf, nwrite);
    if(result)
      return result;
  }
  /* Update stats, write and report progress */
  data->req.bytecount += nwrite;
  ++data->req.bodywrites;
  result = Curl_pgrsSetDownloadCounter(data, data->req.bytecount);
  if(result)
    return result;

  if(excess_len) {
    if(!data->req.ignorebody) {
      infof(data,
            "Excess found writing body:"
            " excess = %zu"
            ", size = %" CURL_FORMAT_CURL_OFF_T
            ", maxdownload = %" CURL_FORMAT_CURL_OFF_T
            ", bytecount = %" CURL_FORMAT_CURL_OFF_T,
            excess_len, data->req.size, data->req.maxdownload,
            data->req.bytecount);
      connclose(data->conn, "excess found in a read");
    }
  }
  else if(nwrite < nbytes) {
    failf(data, "Exceeded the maximum allowed file size "
          "(%" CURL_FORMAT_CURL_OFF_T ") with %"
          CURL_FORMAT_CURL_OFF_T " bytes",
          data->set.max_filesize, data->req.bytecount);
    return CURLE_FILESIZE_EXCEEDED;
  }

  return CURLE_OK;
}

static const struct Curl_cwtype cw_download = {
  "download",
  NULL,
  Curl_cwriter_def_init,
  cw_download_write,
  Curl_cwriter_def_close,
  sizeof(struct Curl_cwriter)
};

/* RAW client writer in phase CURL_CW_RAW that
 * enabled tracing of raw data. */
static CURLcode cw_raw_write(struct Curl_easy *data,
                             struct Curl_cwriter *writer, int type,
                             const char *buf, size_t nbytes)
{
  if(type & CLIENTWRITE_BODY && data->set.verbose && !data->req.ignorebody) {
    Curl_debug(data, CURLINFO_DATA_IN, (char *)buf, nbytes);
  }
  return Curl_cwriter_write(data, writer->next, type, buf, nbytes);
}

static const struct Curl_cwtype cw_raw = {
  "raw",
  NULL,
  Curl_cwriter_def_init,
  cw_raw_write,
  Curl_cwriter_def_close,
  sizeof(struct Curl_cwriter)
};

/* Create an unencoding writer stage using the given handler. */
CURLcode Curl_cwriter_create(struct Curl_cwriter **pwriter,
                                   struct Curl_easy *data,
                                   const struct Curl_cwtype *cwt,
                                   Curl_cwriter_phase phase)
{
  struct Curl_cwriter *writer;
  CURLcode result = CURLE_OUT_OF_MEMORY;

  DEBUGASSERT(cwt->cwriter_size >= sizeof(struct Curl_cwriter));
  writer = (struct Curl_cwriter *) calloc(1, cwt->cwriter_size);
  if(!writer)
    goto out;

  writer->cwt = cwt;
  writer->phase = phase;
  result = cwt->do_init(data, writer);

out:
  *pwriter = result? NULL : writer;
  if(result)
    free(writer);
  return result;
}

void Curl_cwriter_free(struct Curl_easy *data,
                             struct Curl_cwriter *writer)
{
  if(writer) {
    writer->cwt->do_close(data, writer);
    free(writer);
  }
}

size_t Curl_cwriter_count(struct Curl_easy *data, Curl_cwriter_phase phase)
{
  struct Curl_cwriter *w;
  size_t n = 0;

  for(w = data->req.writer_stack; w; w = w->next) {
    if(w->phase == phase)
      ++n;
  }
  return n;
}

static CURLcode do_init_stack(struct Curl_easy *data)
{
  struct Curl_cwriter *writer;
  CURLcode result;

  DEBUGASSERT(!data->req.writer_stack);
  result = Curl_cwriter_create(&data->req.writer_stack,
                               data, &Curl_cwt_out, CURL_CW_CLIENT);
  if(result)
    return result;

  result = Curl_cwriter_create(&writer, data, &cw_download, CURL_CW_PROTOCOL);
  if(result)
    return result;
  result = Curl_cwriter_add(data, writer);
  if(result) {
    Curl_cwriter_free(data, writer);
  }

  result = Curl_cwriter_create(&writer, data, &cw_raw, CURL_CW_RAW);
  if(result)
    return result;
  result = Curl_cwriter_add(data, writer);
  if(result) {
    Curl_cwriter_free(data, writer);
  }
  return result;
}

CURLcode Curl_cwriter_add(struct Curl_easy *data,
                          struct Curl_cwriter *writer)
{
  CURLcode result;
  struct Curl_cwriter **anchor = &data->req.writer_stack;

  if(!*anchor) {
    result = do_init_stack(data);
    if(result)
      return result;
  }

  /* Insert the writer as first in its phase.
   * Skip existing writers of lower phases. */
  while(*anchor && (*anchor)->phase < writer->phase)
    anchor = &((*anchor)->next);
  writer->next = *anchor;
  *anchor = writer;
  return CURLE_OK;
}

struct Curl_cwriter *Curl_cwriter_get_by_name(struct Curl_easy *data,
                                              const char *name)
{
  struct Curl_cwriter *writer;
  for(writer = data->req.writer_stack; writer; writer = writer->next) {
    if(!strcmp(name, writer->cwt->name))
      return writer;
  }
  return NULL;
}

struct Curl_cwriter *Curl_cwriter_get_by_type(struct Curl_easy *data,
                                              const struct Curl_cwtype *cwt)
{
  struct Curl_cwriter *writer;
  for(writer = data->req.writer_stack; writer; writer = writer->next) {
    if(writer->cwt == cwt)
      return writer;
  }
  return NULL;
}

void Curl_cwriter_remove_by_name(struct Curl_easy *data,
                                 const char *name)
{
  struct Curl_cwriter **anchor = &data->req.writer_stack;

  while(*anchor) {
    if(!strcmp(name, (*anchor)->cwt->name)) {
      struct Curl_cwriter *w = (*anchor);
      *anchor = w->next;
      Curl_cwriter_free(data, w);
      continue;
    }
    anchor = &((*anchor)->next);
  }
}