text: // Copyright (c) 2006, Google Inc.
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include "common/linux/http_upload.h"
  
  #include <assert.h>
  #include <dlfcn.h>
  #include "third_party/curl/curl.h"
  
  namespace {
  
  // Callback to get the response data from server.
  static size_t WriteCallback(void *ptr, size_t size,
                              size_t nmemb, void *userp) {
    if (!userp)
      return 0;
  
    string *response = reinterpret_cast<string *>(userp);
    size_t real_size = size * nmemb;
    response->append(reinterpret_cast<char *>(ptr), real_size);
    return real_size;
  }
  
  }  // namespace
  
  namespace google_breakpad {
  
  static const char kUserAgent[] = "Breakpad/1.0 (Linux)";
  
  // static
  bool HTTPUpload::SendRequest(const string &url,
                               const map<string, string> &parameters,
                               const string &upload_file,
                               const string &file_part_name,
                               const string &proxy,
                               const string &proxy_user_pwd,
                               const string &ca_certificate_file,
                               string *response_body,
                               long *response_code,
                               string *error_description) {
    if (response_code != NULL)
      *response_code = 0;
  
    if (!CheckParameters(parameters))
      return false;
  
    // We may have been linked statically; if curl_easy_init is in the
    // current binary, no need to search for a dynamic version.
    void* curl_lib = dlopen(NULL, RTLD_NOW);
    if (!curl_lib || dlsym(curl_lib, "curl_easy_init") == NULL) {
      dlerror();  // Clear dlerror before attempting to open libraries.
      dlclose(curl_lib);
      curl_lib = NULL;
    }
    if (!curl_lib) {
      curl_lib = dlopen("libcurl.so", RTLD_NOW);
    }
    if (!curl_lib) {
      if (error_description != NULL)
        *error_description = dlerror();
      curl_lib = dlopen("libcurl.so.4", RTLD_NOW);
    }
    if (!curl_lib) {
      // Debian gives libcurl a different name when it is built against GnuTLS
      // instead of OpenSSL.
      curl_lib = dlopen("libcurl-gnutls.so.4", RTLD_NOW);
    }
    if (!curl_lib) {
      curl_lib = dlopen("libcurl.so.3", RTLD_NOW);
    }
    if (!curl_lib) {
      return false;
    }
  
    CURL* (*curl_easy_init)(void);
    *(void**) (&curl_easy_init) = dlsym(curl_lib, "curl_easy_init");
    CURL *curl = (*curl_easy_init)();
    if (error_description != NULL)
      *error_description = "No Error";
  
    if (!curl) {
      dlclose(curl_lib);
      return false;
    }
  
    CURLcode err_code = CURLE_OK;
    CURLcode (*curl_easy_setopt)(CURL *, CURLoption, ...);
    *(void**) (&curl_easy_setopt) = dlsym(curl_lib, "curl_easy_setopt");
    (*curl_easy_setopt)(curl, CURLOPT_URL, url.c_str());
    (*curl_easy_setopt)(curl, CURLOPT_USERAGENT, kUserAgent);
    // Set proxy information if necessary.
    if (!proxy.empty())
      (*curl_easy_setopt)(curl, CURLOPT_PROXY, proxy.c_str());
    if (!proxy_user_pwd.empty())
      (*curl_easy_setopt)(curl, CURLOPT_PROXYUSERPWD, proxy_user_pwd.c_str());
  
    if (!ca_certificate_file.empty())
      (*curl_easy_setopt)(curl, CURLOPT_CAINFO, ca_certificate_file.c_str());
  
    struct curl_httppost *formpost = NULL;
    struct curl_httppost *lastptr = NULL;
    // Add form data.
    CURLFORMcode (*curl_formadd)(struct curl_httppost **, struct curl_httppost **, ...);
    *(void**) (&curl_formadd) = dlsym(curl_lib, "curl_formadd");
    map<string, string>::const_iterator iter = parameters.begin();
    for (; iter != parameters.end(); ++iter)
      (*curl_formadd)(&formpost, &lastptr,
                   CURLFORM_COPYNAME, iter->first.c_str(),
                   CURLFORM_COPYCONTENTS, iter->second.c_str(),
                   CURLFORM_END);
  
    // Add form file.
    (*curl_formadd)(&formpost, &lastptr,
                 CURLFORM_COPYNAME, file_part_name.c_str(),
                 CURLFORM_FILE, upload_file.c_str(),
                 CURLFORM_END);
  
    (*curl_easy_setopt)(curl, CURLOPT_HTTPPOST, formpost);
  
    // Disable 100-continue header.
    struct curl_slist *headerlist = NULL;
    char buf[] = "Expect:";
    struct curl_slist* (*curl_slist_append)(struct curl_slist *, const char *);
    *(void**) (&curl_slist_append) = dlsym(curl_lib, "curl_slist_append");
    headerlist = (*curl_slist_append)(headerlist, buf);
    (*curl_easy_setopt)(curl, CURLOPT_HTTPHEADER, headerlist);
  
    if (response_body != NULL) {
      (*curl_easy_setopt)(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
      (*curl_easy_setopt)(curl, CURLOPT_WRITEDATA,
                       reinterpret_cast<void *>(response_body));
    }
  
    // Fail if 400+ is returned from the web server.
    (*curl_easy_setopt)(curl, CURLOPT_FAILONERROR, 1);
  
    CURLcode (*curl_easy_perform)(CURL *);
    *(void**) (&curl_easy_perform) = dlsym(curl_lib, "curl_easy_perform");
    err_code = (*curl_easy_perform)(curl);
    if (response_code != NULL) {
      CURLcode (*curl_easy_getinfo)(CURL *, CURLINFO, ...);
      *(void**) (&curl_easy_getinfo) = dlsym(curl_lib, "curl_easy_getinfo");
      (*curl_easy_getinfo)(curl, CURLINFO_RESPONSE_CODE, response_code);
    }
    const char* (*curl_easy_strerror)(CURLcode);
    *(void**) (&curl_easy_strerror) = dlsym(curl_lib, "curl_easy_strerror");
  #ifndef NDEBUG
    if (err_code != CURLE_OK)
      fprintf(stderr, "Failed to send http request to %s, error: %s\n",
              url.c_str(),
              (*curl_easy_strerror)(err_code));
  #endif
    if (error_description != NULL)
      *error_description = (*curl_easy_strerror)(err_code);
  
    void (*curl_easy_cleanup)(CURL *);
    *(void**) (&curl_easy_cleanup) = dlsym(curl_lib, "curl_easy_cleanup");
    (*curl_easy_cleanup)(curl);
    if (formpost != NULL) {
      void (*curl_formfree)(struct curl_httppost *);
      *(void**) (&curl_formfree) = dlsym(curl_lib, "curl_formfree");
      (*curl_formfree)(formpost);
    }
    if (headerlist != NULL) {
      void (*curl_slist_free_all)(struct curl_slist *);
      *(void**) (&curl_slist_free_all) = dlsym(curl_lib, "curl_slist_free_all");
      (*curl_slist_free_all)(headerlist);
    }
    dlclose(curl_lib);
    return err_code == CURLE_OK;
  }
  
  // static
  bool HTTPUpload::CheckParameters(const map<string, string> &parameters) {
    for (map<string, string>::const_iterator pos = parameters.begin();
         pos != parameters.end(); ++pos) {
      const string &str = pos->first;
      if (str.size() == 0)
        return false;  // disallow empty parameter names
      for (unsigned int i = 0; i < str.size(); ++i) {
        int c = str[i];
        if (c < 32 || c == '"' || c > 127) {
          return false;
        }
      }
    }
    return true;
  }
  
  }  // namespace google_breakpad
  