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3rdparty/curl/share/man/man3/CURLOPT_SSH_KEYFUNCTION.3 5.31 KB
a86c63ca   Hu Chunming   提交三方库文件
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  .\" **************************************************************************
  .\" *                                  _   _ ____  _
  .\" *  Project                     ___| | | |  _ \| |
  .\" *                             / __| | | | |_) | |
  .\" *                            | (__| |_| |  _ <| |___
  .\" *                             \___|\___/|_| \_\_____|
  .\" *
  .\" * Copyright (C) 1998 - 2020, 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.
  .\" *
  .\" **************************************************************************
  .\"
  .TH CURLOPT_SSH_KEYFUNCTION 3 "November 04, 2020" "libcurl 7.77.0" "curl_easy_setopt options"
  
  .SH NAME
  CURLOPT_SSH_KEYFUNCTION \- callback for known host matching logic
  .SH SYNOPSIS
  .nf
  #include <curl/curl.h>
  
  enum curl_khstat {
    CURLKHSTAT_FINE_ADD_TO_FILE,
    CURLKHSTAT_FINE,
    CURLKHSTAT_REJECT, /* reject the connection, return an error */
    CURLKHSTAT_DEFER,  /* do not accept it, but we can't answer right
                          now so this causes a CURLE_DEFER error but
                          otherwise the connection will be left intact
                          etc */
    CURLKHSTAT_FINE_REPLACE
  };
  
  enum curl_khmatch {
    CURLKHMATCH_OK,       /* match */
    CURLKHMATCH_MISMATCH, /* host found, key mismatch! */
    CURLKHMATCH_MISSING,  /* no matching host/key found */
  };
  
  struct curl_khkey {
    const char *key; /* points to a null-terminated string encoded with
                        base64 if len is zero, otherwise to the "raw"
                        data */
    size_t len;
    enum curl_khtype keytype;
  };
  
  int ssh_keycallback(CURL *easy,
                      const struct curl_khkey *knownkey,
                      const struct curl_khkey *foundkey,
                      enum curl_khmatch,
                      void *clientp);
  
  CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_KEYFUNCTION,
                            ssh_keycallback);
  .SH DESCRIPTION
  Pass a pointer to your callback function, which should match the prototype
  shown above.
  
  It gets called when the known_host matching has been done, to allow the
  application to act and decide for libcurl how to proceed. The callback will
  only be called if \fICURLOPT_SSH_KNOWNHOSTS(3)\fP is also set.
  
  This callback function gets passed the CURL handle, the key from the
  known_hosts file \fIknownkey\fP, the key from the remote site \fIfoundkey\fP,
  info from libcurl on the matching status and a custom pointer (set with
  \fICURLOPT_SSH_KEYDATA(3)\fP). It MUST return one of the following return
  codes to tell libcurl how to act:
  .IP CURLKHSTAT_FINE_REPLACE
  The new host+key is accepted and libcurl will replace the old host+key into
  the known_hosts file before continuing with the connection.  This will also
  add the new host+key combo to the known_host pool kept in memory if it wasn't
  already present there. The adding of data to the file is done by completely
  replacing the file with a new copy, so the permissions of the file must allow
  this. (Added in 7.73.0)
  .IP CURLKHSTAT_FINE_ADD_TO_FILE
  The host+key is accepted and libcurl will append it to the known_hosts file
  before continuing with the connection. This will also add the host+key combo
  to the known_host pool kept in memory if it wasn't already present there. The
  adding of data to the file is done by completely replacing the file with a new
  copy, so the permissions of the file must allow this.
  .IP CURLKHSTAT_FINE
  The host+key is accepted libcurl will continue with the connection. This will
  also add the host+key combo to the known_host pool kept in memory if it wasn't
  already present there.
  .IP CURLKHSTAT_REJECT
  The host+key is rejected. libcurl will deny the connection to continue and it
  will be closed.
  .IP CURLKHSTAT_DEFER
  The host+key is rejected, but the SSH connection is asked to be kept alive.
  This feature could be used when the app wants to somehow return back and act
  on the host+key situation and then retry without needing the overhead of
  setting it up from scratch again.
  .SH DEFAULT
  NULL
  .SH PROTOCOLS
  SFTP and SCP
  .SH EXAMPLE
  .nf
  static int keycb(CURL *easy,
                   const struct curl_khkey *knownkey,
                   const struct curl_khkey *foundkey,
                   enum curl_khmatch,
                   void *clientp)
  {
    /* 'clientp' points to the callback_data struct */
    /* investigate the situation and return the correct value */
    return CURLKHSTAT_FINE_ADD_TO_FILE;
  }
  {
    curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/thisfile.txt");
    curl_easy_setopt(curl, CURLOPT_SSH_KEYFUNCTION, keycb);
    curl_easy_setopt(curl, CURLOPT_SSH_KEYDATA, &callback_data);
    curl_easy_setopt(curl, CURLOPT_SSH_KNOWNHOSTS, "/home/user/known_hosts");
  
    curl_easy_perform(curl);
  }
  .fi
  .SH AVAILABILITY
  Added in 7.19.6
  .SH RETURN VALUE
  Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
  .SH "SEE ALSO"
  .BR CURLOPT_SSH_KEYDATA "(3), " CURLOPT_SSH_KNOWNHOSTS "(3), "