linux: Add HTTPTransportLibcurl for Linux (but not Android)

BUG=crashpad:30
TEST=crashpad_util_test HTTPTransport.*

Change-Id: Ifef812830fe2d778f400467d93771dc166cef390

DEPS

@@ -38,7 +38,7 @@ deps = {
 
   'crashpad/third_party/mini_chromium/mini_chromium':
       Var('chromium_git') + '/chromium/mini_chromium@' +
-      '3a2d52d74c9af5277bf6456cc00ae728f89c4898',
+      '9e0d322ae9f87acbe17c4ced025319b4964bf0b7',
   'crashpad/third_party/zlib/zlib':
       Var('chromium_git') + '/chromium/src/third_party/zlib@' +
       '13dc246a58e4b72104d35f9b1809af95221ebda7',

util/net/http_transport_libcurl.cc

@@ -0,0 +1,366 @@
+// Copyright 2017 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/net/http_transport.h"
+
+#include <curl/curl.h>
+#include <string.h>
+#include <sys/utsname.h>
+
+#include <algorithm>
+#include <limits>
+
+#include "base/logging.h"
+#include "base/numerics/safe_math.h"
+#include "base/scoped_generic.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "build/build_config.h"
+#include "package.h"
+#include "util/net/http_body.h"
+#include "util/numeric/safe_assignment.h"
+
+namespace crashpad {
+
+namespace {
+
+std::string UserAgent() {
+  std::string user_agent = base::StringPrintf(
+      "%s/%s %s", PACKAGE_NAME, PACKAGE_VERSION, curl_version());
+
+  utsname os;
+  if (uname(&os) != 0) {
+    PLOG(WARNING) << "uname";
+  } else {
+    // Match the architecture name that would be used by the kernel, so that the
+    // strcmp() below can omit the kernel’s architecture name if it’s the same
+    // as the user process’ architecture. On Linux, these names are normally
+    // defined in each architecture’s Makefile as UTS_MACHINE, but can be
+    // overridden in architecture-specific configuration as COMPAT_UTS_MACHINE.
+    // See linux-4.4.52/arch/*/Makefile and
+    // linux-4.4.52/arch/*/include/asm/compat.h. In turn, on some systems, these
+    // names are further overridden or refined in early kernel startup code by
+    // modifying the string returned by linux-4.4.52/include/linux/utsname.h
+    // init_utsname() as noted.
+#if defined(ARCH_CPU_X86)
+    // linux-4.4.52/arch/x86/kernel/cpu/bugs.c check_bugs() sets the first digit
+    // to 4, 5, or 6, but no higher. Assume 6.
+    const char arch[] = "i686";
+#elif defined(ARCH_CPU_X86_64)
+    const char arch[] = "x86_64";
+#elif defined(ARCH_CPU_ARMEL)
+    // linux-4.4.52/arch/arm/kernel/setup.c setup_processor() bases the string
+    // on the ARM processor name and a character identifying little- or
+    // big-endian. The processor name comes from a definition in
+    // arch/arm/mm/proc-*.S. Assume armv7, little-endian.
+    const char arch[] = "armv7l";
+#elif defined(ARCH_CPU_ARM64)
+    // ARM64 uses aarch64 or aarch64_be as directed by ELF_PLATFORM. See
+    // linux-4.4.52/arch/arm64/kernel/setup.c setup_arch(). Assume
+    // little-endian.
+    const char arch[] = "aarch64";
+#elif defined(ARCH_CPU_MIPSEL)
+    const char arch[] = "mips";
+#elif defined(ARCH_CPU_MIPS64EL)
+    const char arch[] = "mips64";
+#else
+#error Port
+#endif
+
+    user_agent.append(
+        base::StringPrintf(" %s/%s (%s", os.sysname, os.release, arch));
+    if (strcmp(arch, os.machine) != 0) {
+      user_agent.append(base::StringPrintf("; %s", os.machine));
+    }
+    user_agent.append(1, ')');
+  }
+
+  return user_agent;
+}
+
+std::string CurlErrorMessage(CURLcode curl_err, const std::string& base) {
+  return base::StringPrintf(
+      "%s: %s (%d)", base.c_str(), curl_easy_strerror(curl_err), curl_err);
+}
+
+struct ScopedCURLTraits {
+  static CURL* InvalidValue() { return nullptr; }
+  static void Free(CURL* curl) {
+    if (curl) {
+      curl_easy_cleanup(curl);
+    }
+  }
+};
+using ScopedCURL = base::ScopedGeneric<CURL*, ScopedCURLTraits>;
+
+class CurlSList {
+ public:
+  CurlSList() : list_(nullptr) {}
+  ~CurlSList() {
+    if (list_) {
+      curl_slist_free_all(list_);
+    }
+  }
+
+  curl_slist* get() const { return list_; }
+
+  bool Append(const char* data) {
+    curl_slist* list = curl_slist_append(list_, data);
+    if (!list_) {
+      list_ = list;
+    }
+    return list != nullptr;
+  }
+
+ private:
+  curl_slist* list_;
+
+  DISALLOW_COPY_AND_ASSIGN(CurlSList);
+};
+
+class ScopedClearString {
+ public:
+  explicit ScopedClearString(std::string* string) : string_(string) {}
+
+  ~ScopedClearString() {
+    if (string_) {
+      string_->clear();
+    }
+  }
+
+  void Disarm() { string_ = nullptr; }
+
+ private:
+  std::string* string_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedClearString);
+};
+
+class HTTPTransportLibcurl final : public HTTPTransport {
+ public:
+  HTTPTransportLibcurl();
+  ~HTTPTransportLibcurl() override;
+
+  // HTTPTransport:
+  bool ExecuteSynchronously(std::string* response_body) override;
+
+ private:
+  static size_t ReadRequestBody(char* buffer,
+                                size_t size,
+                                size_t nitems,
+                                void* userdata);
+  static size_t WriteResponseBody(char* buffer,
+                                  size_t size,
+                                  size_t nitems,
+                                  void* userdata);
+
+  DISALLOW_COPY_AND_ASSIGN(HTTPTransportLibcurl);
+};
+
+HTTPTransportLibcurl::HTTPTransportLibcurl() : HTTPTransport() {}
+
+HTTPTransportLibcurl::~HTTPTransportLibcurl() {}
+
+bool HTTPTransportLibcurl::ExecuteSynchronously(std::string* response_body) {
+  DCHECK(body_stream());
+
+  response_body->clear();
+
+  // curl_easy_init() will do this on the first call if it hasn’t been done yet,
+  // but not in a thread-safe way as is done here.
+  static CURLcode curl_global_init_err = []() {
+    return curl_global_init(CURL_GLOBAL_DEFAULT);
+  }();
+  if (curl_global_init_err != CURLE_OK) {
+    LOG(ERROR) << CurlErrorMessage(curl_global_init_err, "curl_global_init");
+    return false;
+  }
+
+  CurlSList curl_headers;
+  ScopedCURL curl(curl_easy_init());
+  if (!curl.get()) {
+    LOG(ERROR) << "curl_easy_init";
+    return false;
+  }
+
+// These macros wrap the repetitive “try something, log an error and return
+// false on failure” pattern. Macros are convenient because the log messages
+// will point to the correct line number, which can help pinpoint a problem when
+// there are as many calls to these functions as there are here.
+#define TRY_CURL_EASY_SETOPT(curl, option, parameter)                    \
+  do {                                                                   \
+    CURLcode curl_err = curl_easy_setopt((curl), (option), (parameter)); \
+    if (curl_err != CURLE_OK) {                                          \
+      LOG(ERROR) << CurlErrorMessage(curl_err, "curl_easy_setopt");      \
+      return false;                                                      \
+    }                                                                    \
+  } while (false)
+#define TRY_CURL_SLIST_APPEND(slist, data) \
+  do {                                     \
+    if (!(slist).Append(data)) {           \
+      LOG(ERROR) << "curl_slist_append";   \
+      return false;                        \
+    }                                      \
+  } while (false)
+
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_USERAGENT, UserAgent().c_str());
+
+  // Accept and automatically decode any encoding that libcurl understands.
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_ACCEPT_ENCODING, "");
+
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_URL, url().c_str());
+
+  const int kMillisecondsPerSecond = 1E3;
+  TRY_CURL_EASY_SETOPT(curl.get(),
+                       CURLOPT_TIMEOUT_MS,
+                       static_cast<long>(timeout() * kMillisecondsPerSecond));
+
+  // If the request body size is known ahead of time, a Content-Length header
+  // field will be present. Store that to use as CURLOPT_POSTFIELDSIZE_LARGE,
+  // which will both set the Content-Length field in the request header and
+  // inform libcurl of the request body size. Otherwise, use Transfer-Encoding:
+  // chunked, which does not require advance knowledge of the request body size.
+  bool chunked = true;
+  size_t content_length;
+  for (const auto& pair : headers()) {
+    if (pair.first == kContentLength) {
+      chunked = !base::StringToSizeT(pair.second, &content_length);
+      DCHECK(!chunked);
+    } else {
+      TRY_CURL_SLIST_APPEND(curl_headers,
+                            (pair.first + ": " + pair.second).c_str());
+    }
+  }
+
+  if (method() == "POST") {
+    TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_POST, 1l);
+
+    // By default when sending a POST request, libcurl includes an “Expect:
+    // 100-continue” header field. Althogh this header is specified in HTTP/1.1
+    // (RFC 2616 §8.2.3, RFC 7231 §5.1.1), even collection servers that claim to
+    // speak HTTP/1.1 may not respond to it. When sending this header field,
+    // libcurl will wait for one second for the server to respond with a “100
+    // Continue” status before continuing to transmit the request body. This
+    // delay is avoided by telling libcurl not to send this header field at all.
+    // The drawback is that certain HTTP error statuses may not be received
+    // until after substantial amounts of data have been sent to the server.
+    TRY_CURL_SLIST_APPEND(curl_headers, "Expect:");
+
+    if (chunked) {
+      TRY_CURL_SLIST_APPEND(curl_headers, "Transfer-Encoding: chunked");
+    } else {
+      curl_off_t content_length_curl;
+      if (!AssignIfInRange(&content_length_curl, content_length)) {
+        LOG(ERROR) << base::StringPrintf("Content-Length %zu too large",
+                                         content_length);
+        return false;
+      }
+      TRY_CURL_EASY_SETOPT(
+          curl.get(), CURLOPT_POSTFIELDSIZE_LARGE, content_length_curl);
+    }
+  } else if (method() != "GET") {
+    // Untested.
+    TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_CUSTOMREQUEST, method().c_str());
+  }
+
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_HTTPHEADER, curl_headers.get());
+
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_READFUNCTION, ReadRequestBody);
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_READDATA, this);
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_WRITEFUNCTION, WriteResponseBody);
+  TRY_CURL_EASY_SETOPT(curl.get(), CURLOPT_WRITEDATA, response_body);
+
+#undef TRY_CURL_EASY_SETOPT
+#undef TRY_CURL_SLIST_APPEND
+
+  // If a partial response body is received and then a failure occurs, ensure
+  // that response_body is cleared.
+  ScopedClearString clear_response_body(response_body);
+
+  // Do it.
+  CURLcode curl_err = curl_easy_perform(curl.get());
+  if (curl_err != CURLE_OK) {
+    LOG(ERROR) << CurlErrorMessage(curl_err, "curl_easy_perform");
+    return false;
+  }
+
+  long status;
+  curl_err = curl_easy_getinfo(curl.get(), CURLINFO_RESPONSE_CODE, &status);
+  if (curl_err != CURLE_OK) {
+    LOG(ERROR) << CurlErrorMessage(curl_err, "curl_easy_getinfo");
+    return false;
+  }
+
+  if (status != 200) {
+    LOG(ERROR) << base::StringPrintf("HTTP status %ld", status);
+    return false;
+  }
+
+  // The response body is complete. Don’t clear it.
+  clear_response_body.Disarm();
+
+  return true;
+}
+
+// static
+size_t HTTPTransportLibcurl::ReadRequestBody(char* buffer,
+                                             size_t size,
+                                             size_t nitems,
+                                             void* userdata) {
+  HTTPTransportLibcurl* self =
+      reinterpret_cast<HTTPTransportLibcurl*>(userdata);
+
+  // This libcurl callback mimics the silly stdio-style fread() interface: size
+  // and nitems have been separated and must be multiplied.
+  base::CheckedNumeric<size_t> checked_len = base::CheckMul(size, nitems);
+  size_t len = checked_len.ValueOrDefault(std::numeric_limits<size_t>::max());
+
+  // Limit the read to what can be expressed in a FileOperationResult.
+  len = std::min(
+      len,
+      static_cast<size_t>(std::numeric_limits<FileOperationResult>::max()));
+
+  FileOperationResult bytes_read = self->body_stream()->GetBytesBuffer(
+      reinterpret_cast<uint8_t*>(buffer), len);
+  if (bytes_read < 0) {
+    return CURL_READFUNC_ABORT;
+  }
+
+  return bytes_read;
+}
+
+// static
+size_t HTTPTransportLibcurl::WriteResponseBody(char* buffer,
+                                               size_t size,
+                                               size_t nitems,
+                                               void* userdata) {
+  std::string* response_body = reinterpret_cast<std::string*>(userdata);
+
+  // This libcurl callback mimics the silly stdio-style fread() interface: size
+  // and nitems have been separated and must be multiplied.
+  base::CheckedNumeric<size_t> checked_len = base::CheckMul(size, nitems);
+  size_t len = checked_len.ValueOrDefault(std::numeric_limits<size_t>::max());
+
+  response_body->append(buffer, len);
+  return len;
+}
+
+}  // namespace
+
+// static
+std::unique_ptr<HTTPTransport> HTTPTransport::Create() {
+  return std::unique_ptr<HTTPTransport>(new HTTPTransportLibcurl());
+}
+
+}  // namespace crashpad

util/util.gyp

@@ -119,6 +119,7 @@
         'net/http_multipart_builder.h',
         'net/http_transport.cc',
         'net/http_transport.h',
+        'net/http_transport_libcurl.cc',
         'net/http_transport_mac.mm',
         'net/http_transport_win.cc',
         'numeric/checked_address_range.cc',
@@ -300,6 +301,17 @@
             'win/capture_context.asm',
           ],
         }],
+        ['OS=="linux"', {
+          'link_settings': {
+            'libraries': [
+              '-lcurl',
+            ],
+          },
+        }, {  # else: OS!="linux"
+          'sources!': [
+            'net/http_transport_libcurl.cc',
+          ],
+        }],
       ],
     },
   ],