/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Linus Nielsen Feltzing, <linus@haxx.se>

 * 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"

#include "urldata.h"

#include "url.h"

#include "cfilters.h"

#include "progress.h"

#include "multiif.h"

#include "multi_ev.h"

#include "curl_trc.h"

#include "cshutdn.h"

#include "sigpipe.h"

#include "connect.h"

#include "select.h"

#include "curlx/strparse.h"

static void cshutdn_run_conn_handler(struct Curl_easy *data,

                                     struct connectdata *conn)

{

  if(!conn->bits.shutdown_handler) {

    if(conn->handler && conn->handler->disconnect) {

      /* Some disconnect handlers do a blocking wait on server responses.

       * FTP/IMAP/SMTP and SFTP are among them. When using the internal

       * handle, set an overall short timeout so we do not hang for the

       * default 120 seconds. */

      if(data->state.internal) {

        data->set.timeout = DEFAULT_SHUTDOWN_TIMEOUT_MS;

        (void)Curl_pgrsTime(data, TIMER_STARTOP);

      }

      /* This is set if protocol-specific cleanups should be made */

      DEBUGF(infof(data, "connection #%" FMT_OFF_T

                   ", shutdown protocol handler (aborted=%d)",

                   conn->connection_id, conn->bits.aborted));

      /* There are protocol handlers that block on retrieving

       * server responses here (FTP). Set a short timeout. */

      conn->handler->disconnect(data, conn, conn->bits.aborted);

    }

    conn->bits.shutdown_handler = TRUE;

  }

}

static void cshutdn_run_once(struct Curl_easy *data,

                             struct connectdata *conn,

                             bool *done)

{

  CURLcode r1, r2;

  bool done1, done2;

  /* We expect to be attached when called */

  DEBUGASSERT(data->conn == conn);

  cshutdn_run_conn_handler(data, conn);

  if(conn->bits.shutdown_filters) {

    *done = TRUE;

    return;

  }

  if(!conn->connect_only && Curl_conn_is_connected(conn, FIRSTSOCKET))

    r1 = Curl_conn_shutdown(data, FIRSTSOCKET, &done1);

  else {

    r1 = CURLE_OK;

    done1 = TRUE;

  }

  if(!conn->connect_only && Curl_conn_is_connected(conn, SECONDARYSOCKET))

    r2 = Curl_conn_shutdown(data, SECONDARYSOCKET, &done2);

  else {

    r2 = CURLE_OK;

    done2 = TRUE;

  }

  /* we are done when any failed or both report success */

  *done = (r1 || r2 || (done1 && done2));

  if(*done)

    conn->bits.shutdown_filters = TRUE;

}

void Curl_cshutdn_run_once(struct Curl_easy *data,

                           struct connectdata *conn,

                           bool *done)

{

  DEBUGASSERT(!data->conn);

  Curl_attach_connection(data, conn);

  cshutdn_run_once(data, conn, done);

  CURL_TRC_M(data, "[SHUTDOWN] shutdown, done=%d", *done);

  Curl_detach_connection(data);

}

void Curl_cshutdn_terminate(struct Curl_easy *data,

                            struct connectdata *conn,

                            bool do_shutdown)

{

  struct Curl_easy *admin = data;

  bool done;

  /* there must be a connection to close */

  DEBUGASSERT(conn);

  /* it must be removed from the connection pool */

  DEBUGASSERT(!conn->bits.in_cpool);

  /* the transfer must be detached from the connection */

  DEBUGASSERT(data && !data->conn);

  /* If we can obtain an internal admin handle, use that to attach

   * and terminate the connection. Some protocol will try to mess with

   * `data` during shutdown and we do not want that with a `data` from

   * the application. */

  if(data->multi && data->multi->admin)

    admin = data->multi->admin;

  Curl_attach_connection(admin, conn);

  cshutdn_run_conn_handler(admin, conn);

  if(do_shutdown) {

    /* Make a last attempt to shutdown handlers and filters, if

     * not done so already. */

    cshutdn_run_once(admin, conn, &done);

  }

  CURL_TRC_M(admin, "[SHUTDOWN] %sclosing connection #%" FMT_OFF_T,

             conn->bits.shutdown_filters ? "" : "force ",

             conn->connection_id);

  Curl_conn_close(admin, SECONDARYSOCKET);

  Curl_conn_close(admin, FIRSTSOCKET);

  Curl_detach_connection(admin);

  if(data->multi)

    Curl_multi_ev_conn_done(data->multi, data, conn);

  Curl_conn_free(admin, conn);

  if(data->multi) {

    CURL_TRC_M(data, "[SHUTDOWN] trigger multi connchanged");

    Curl_multi_connchanged(data->multi);

  }

}

static bool cshutdn_destroy_oldest(struct cshutdn *cshutdn,

                                   struct Curl_easy *data,

                                   const char *destination)

{

  struct Curl_llist_node *e;

  struct connectdata *conn;

  e = Curl_llist_head(&cshutdn->list);

  while(e) {

    conn = Curl_node_elem(e);

    if(!destination || !strcmp(destination, conn->destination))

      break;

    e = Curl_node_next(e);

  }

  if(e) {

    SIGPIPE_VARIABLE(pipe_st);

    conn = Curl_node_elem(e);

    Curl_node_remove(e);

    sigpipe_init(&pipe_st);

    sigpipe_apply(data, &pipe_st);

    Curl_cshutdn_terminate(data, conn, FALSE);

    sigpipe_restore(&pipe_st);

    return TRUE;

  }

  return FALSE;

}

bool Curl_cshutdn_close_oldest(struct Curl_easy *data,

                               const char *destination)

{

  if(data && data->multi) {

    struct cshutdn *csd = &data->multi->cshutdn;

    return cshutdn_destroy_oldest(csd, data, destination);

  }

  return FALSE;

}

#define NUM_POLLS_ON_STACK 10

static CURLcode cshutdn_wait(struct cshutdn *cshutdn,

                             struct Curl_easy *data,

                             int timeout_ms)

{

  struct pollfd a_few_on_stack[NUM_POLLS_ON_STACK];

  struct curl_pollfds cpfds;

  CURLcode result;

  Curl_pollfds_init(&cpfds, a_few_on_stack, NUM_POLLS_ON_STACK);

  result = Curl_cshutdn_add_pollfds(cshutdn, data, &cpfds);

  if(result)

    goto out;

  Curl_poll(cpfds.pfds, cpfds.n, CURLMIN(timeout_ms, 1000));

out:

  Curl_pollfds_cleanup(&cpfds);

  return result;

}

static void cshutdn_perform(struct cshutdn *cshutdn,

                            struct Curl_easy *data)

{

  struct Curl_llist_node *e = Curl_llist_head(&cshutdn->list);

  struct Curl_llist_node *enext;

  struct connectdata *conn;

  timediff_t next_expire_ms = 0, ms;

  bool done;

  if(!e)

    return;

  CURL_TRC_M(data, "[SHUTDOWN] perform on %zu connections",

             Curl_llist_count(&cshutdn->list));

  while(e) {

    enext = Curl_node_next(e);

    conn = Curl_node_elem(e);

    Curl_cshutdn_run_once(data, conn, &done);

    if(done) {

      Curl_node_remove(e);

      Curl_cshutdn_terminate(data, conn, FALSE);

    }

    else {

      /* idata has one timer list, but maybe more than one connection.

       * Set EXPIRE_SHUTDOWN to the smallest time left for all. */

      ms = Curl_conn_shutdown_timeleft(data, conn);

      if(ms && ms < next_expire_ms)

        next_expire_ms = ms;

    }

    e = enext;

  }

  if(next_expire_ms)

    Curl_expire_ex(data, next_expire_ms, EXPIRE_SHUTDOWN);

}

static void cshutdn_terminate_all(struct cshutdn *cshutdn,

                                  struct Curl_easy *data,

                                  int timeout_ms)

{

  struct curltime started = *Curl_pgrs_now(data);

  struct Curl_llist_node *e;

  SIGPIPE_VARIABLE(pipe_st);

  DEBUGASSERT(cshutdn);

  DEBUGASSERT(data);

  CURL_TRC_M(data, "[SHUTDOWN] shutdown all");

  sigpipe_init(&pipe_st);

  sigpipe_apply(data, &pipe_st);

  while(Curl_llist_head(&cshutdn->list)) {

    timediff_t spent_ms;

    int remain_ms;

    cshutdn_perform(cshutdn, data);

    if(!Curl_llist_head(&cshutdn->list)) {

      CURL_TRC_M(data, "[SHUTDOWN] shutdown finished cleanly");

      break;

    }

    /* wait for activity, timeout or "nothing" */

    spent_ms = curlx_ptimediff_ms(Curl_pgrs_now(data), &started);

    if(spent_ms >= (timediff_t)timeout_ms) {

      CURL_TRC_M(data, "[SHUTDOWN] shutdown finished, %s",

                 (timeout_ms > 0) ? "timeout" : "best effort done");

      break;

    }

    remain_ms = timeout_ms - (int)spent_ms;

    if(cshutdn_wait(cshutdn, data, remain_ms)) {

      CURL_TRC_M(data, "[SHUTDOWN] shutdown finished, aborted");

      break;

    }

  }

  /* Terminate any remaining. */

  e = Curl_llist_head(&cshutdn->list);

  while(e) {

    struct connectdata *conn = Curl_node_elem(e);

    Curl_node_remove(e);

    Curl_cshutdn_terminate(data, conn, FALSE);

    e = Curl_llist_head(&cshutdn->list);

  }

  DEBUGASSERT(!Curl_llist_count(&cshutdn->list));

  sigpipe_restore(&pipe_st);

}

int Curl_cshutdn_init(struct cshutdn *cshutdn,

                      struct Curl_multi *multi)

{

  DEBUGASSERT(multi);

  cshutdn->multi = multi;

  Curl_llist_init(&cshutdn->list, NULL);

  cshutdn->initialised = TRUE;

  return 0; /* good */

}

void Curl_cshutdn_destroy(struct cshutdn *cshutdn,

                          struct Curl_easy *data)

{

  if(cshutdn->initialised && data) {

    int timeout_ms = 0;

    /* Just for testing, run graceful shutdown */

#ifdef DEBUGBUILD

    {

      const char *p = getenv("CURL_GRACEFUL_SHUTDOWN");

      if(p) {

        curl_off_t l;

        if(!curlx_str_number(&p, &l, INT_MAX))

          timeout_ms = (int)l;

      }

    }

#endif

    CURL_TRC_M(data, "[SHUTDOWN] destroy, %zu connections, timeout=%dms",

               Curl_llist_count(&cshutdn->list), timeout_ms);

    cshutdn_terminate_all(cshutdn, data, timeout_ms);

  }

  cshutdn->multi = NULL;

}

size_t Curl_cshutdn_count(struct Curl_easy *data)

{

  if(data && data->multi) {

    struct cshutdn *csd = &data->multi->cshutdn;

    return Curl_llist_count(&csd->list);

  }

  return 0;

}

size_t Curl_cshutdn_dest_count(struct Curl_easy *data,

                               const char *destination)

{

  if(data && data->multi) {

    struct cshutdn *csd = &data->multi->cshutdn;

    size_t n = 0;

    struct Curl_llist_node *e = Curl_llist_head(&csd->list);

    while(e) {

      struct connectdata *conn = Curl_node_elem(e);

      if(!strcmp(destination, conn->destination))

        ++n;

      e = Curl_node_next(e);

    }

    return n;

  }

  return 0;

}

static CURLMcode cshutdn_update_ev(struct cshutdn *cshutdn,

                                   struct Curl_easy *data,

                                   struct connectdata *conn)

{

  CURLMcode mresult;

  DEBUGASSERT(cshutdn);

  DEBUGASSERT(cshutdn->multi->socket_cb);

  Curl_attach_connection(data, conn);

  mresult = Curl_multi_ev_assess_conn(cshutdn->multi, data, conn);

  Curl_detach_connection(data);

  return mresult;

}

void Curl_cshutdn_add(struct cshutdn *cshutdn,

                      struct connectdata *conn,

                      size_t conns_in_pool)

{

  struct Curl_easy *data = cshutdn->multi->admin;

  size_t max_total = cshutdn->multi->max_total_connections;

  /* Add the connection to our shutdown list for non-blocking shutdown

   * during multi processing. */

  if(max_total > 0 && (max_total <=

        (conns_in_pool + Curl_llist_count(&cshutdn->list)))) {

    CURL_TRC_M(data, "[SHUTDOWN] discarding oldest shutdown connection "

               "due to connection limit of %zu", max_total);

    cshutdn_destroy_oldest(cshutdn, data, NULL);

  }

  if(cshutdn->multi->socket_cb) {

    if(cshutdn_update_ev(cshutdn, data, conn)) {

      CURL_TRC_M(data, "[SHUTDOWN] update events failed, discarding #%"

                 FMT_OFF_T, conn->connection_id);

      Curl_cshutdn_terminate(data, conn, FALSE);

      return;

    }

  }

  Curl_llist_append(&cshutdn->list, conn, &conn->cshutdn_node);

  CURL_TRC_M(data, "[SHUTDOWN] added #%" FMT_OFF_T

             " to shutdowns, now %zu conns in shutdown",

             conn->connection_id, Curl_llist_count(&cshutdn->list));

}

static void cshutdn_multi_socket(struct cshutdn *cshutdn,

                                 struct Curl_easy *data,

                                 curl_socket_t s)

{

  struct Curl_llist_node *e;

  struct connectdata *conn;

  bool done;

  DEBUGASSERT(cshutdn->multi->socket_cb);

  e = Curl_llist_head(&cshutdn->list);

  while(e) {

    conn = Curl_node_elem(e);

    if(s == conn->sock[FIRSTSOCKET] || s == conn->sock[SECONDARYSOCKET]) {

      Curl_cshutdn_run_once(data, conn, &done);

      if(done || cshutdn_update_ev(cshutdn, data, conn)) {

        Curl_node_remove(e);

        Curl_cshutdn_terminate(data, conn, FALSE);

      }

      break;

    }

    e = Curl_node_next(e);

  }

}

void Curl_cshutdn_perform(struct cshutdn *cshutdn,

                          struct Curl_easy *data,

                          curl_socket_t s)

{

  if((s == CURL_SOCKET_TIMEOUT) || (!cshutdn->multi->socket_cb))

    cshutdn_perform(cshutdn, data);

  else

    cshutdn_multi_socket(cshutdn, data, s);

}

/* return fd_set info about the shutdown connections */

void Curl_cshutdn_setfds(struct cshutdn *cshutdn,

                         struct Curl_easy *data,

                         fd_set *read_fd_set, fd_set *write_fd_set,

                         int *maxfd)

{

  if(Curl_llist_head(&cshutdn->list)) {

    struct Curl_llist_node *e;

    struct easy_pollset ps;

    Curl_pollset_init(&ps);

    for(e = Curl_llist_head(&cshutdn->list); e; e = Curl_node_next(e)) {

      unsigned int i;

      struct connectdata *conn = Curl_node_elem(e);

      CURLcode result;

      Curl_pollset_reset(&ps);

      Curl_attach_connection(data, conn);

      result = Curl_conn_adjust_pollset(data, conn, &ps);

      Curl_detach_connection(data);

      if(result)

        continue;

      for(i = 0; i < ps.n; i++) {

        curl_socket_t sock = ps.sockets[i];

        if(!FDSET_SOCK(sock))

          continue;

#ifdef __DJGPP__

#pragma GCC diagnostic push

#pragma GCC diagnostic ignored "-Warith-conversion"

#endif

        if(ps.actions[i] & CURL_POLL_IN)

          FD_SET(sock, read_fd_set);

        if(ps.actions[i] & CURL_POLL_OUT)

          FD_SET(sock, write_fd_set);

#ifdef __DJGPP__

#pragma GCC diagnostic pop

#endif

        if((ps.actions[i] & (CURL_POLL_OUT | CURL_POLL_IN)) &&

           ((int)sock > *maxfd))

          *maxfd = (int)sock;

      }

    }

    Curl_pollset_cleanup(&ps);

  }

}

/* return information about the shutdown connections */

unsigned int Curl_cshutdn_add_waitfds(struct cshutdn *cshutdn,

                                      struct Curl_easy *data,

                                      struct Curl_waitfds *cwfds)

{

  unsigned int need = 0;

  if(Curl_llist_head(&cshutdn->list)) {

    struct Curl_llist_node *e;

    struct easy_pollset ps;

    struct connectdata *conn;

    CURLcode result;

    Curl_pollset_init(&ps);

    for(e = Curl_llist_head(&cshutdn->list); e; e = Curl_node_next(e)) {

      conn = Curl_node_elem(e);

      Curl_pollset_reset(&ps);

      Curl_attach_connection(data, conn);

      result = Curl_conn_adjust_pollset(data, conn, &ps);

      Curl_detach_connection(data);

      if(!result)

        need += Curl_waitfds_add_ps(cwfds, &ps);

    }

    Curl_pollset_cleanup(&ps);

  }

  return need;

}

CURLcode Curl_cshutdn_add_pollfds(struct cshutdn *cshutdn,

                                  struct Curl_easy *data,

                                  struct curl_pollfds *cpfds)

{

  CURLcode result = CURLE_OK;

  if(Curl_llist_head(&cshutdn->list)) {

    struct Curl_llist_node *e;

    struct easy_pollset ps;

    struct connectdata *conn;

    Curl_pollset_init(&ps);

    for(e = Curl_llist_head(&cshutdn->list); e; e = Curl_node_next(e)) {

      conn = Curl_node_elem(e);

      Curl_pollset_reset(&ps);

      Curl_attach_connection(data, conn);

      result = Curl_conn_adjust_pollset(data, conn, &ps);

      Curl_detach_connection(data);

      if(!result)

        result = Curl_pollfds_add_ps(cpfds, &ps);

      if(result) {

        Curl_pollset_cleanup(&ps);

        Curl_pollfds_cleanup(cpfds);

        goto out;

      }

    }

    Curl_pollset_cleanup(&ps);

  }

out:

  return result;

}