1 //===-- llvm/Debuginfod/HTTPServer.cpp - HTTP server library -----*- C++-*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 ///
11 /// This file defines the methods of the HTTPServer class and the streamFile
12 /// function.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/Debuginfod/HTTPServer.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/Support/Errc.h"
20 #include "llvm/Support/Error.h"
21 #include "llvm/Support/FileSystem.h"
22 #include "llvm/Support/MemoryBuffer.h"
23 #include "llvm/Support/Regex.h"
24 
25 #ifdef LLVM_ENABLE_HTTPLIB
26 #include "httplib.h"
27 #endif
28 
29 using namespace llvm;
30 
31 bool llvm::streamFile(HTTPServerRequest &Request, StringRef FilePath) {
32   Expected<sys::fs::file_t> FDOrErr = sys::fs::openNativeFileForRead(FilePath);
33   if (Error Err = FDOrErr.takeError()) {
34     consumeError(std::move(Err));
35     Request.setResponse({404u, "text/plain", "Could not open file to read.\n"});
36     return false;
37   }
38   ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
39       MemoryBuffer::getOpenFile(*FDOrErr, FilePath,
40                                 /*FileSize=*/-1,
41                                 /*RequiresNullTerminator=*/false);
42   sys::fs::closeFile(*FDOrErr);
43   if (Error Err = errorCodeToError(MBOrErr.getError())) {
44     consumeError(std::move(Err));
45     Request.setResponse({404u, "text/plain", "Could not memory-map file.\n"});
46     return false;
47   }
48   // Lambdas are copied on conversion to to std::function, preventing use of
49   // smart pointers.
50   MemoryBuffer *MB = MBOrErr->release();
51   Request.setResponse({200u, "application/octet-stream", MB->getBufferSize(),
52                        [=](size_t Offset, size_t Length) -> StringRef {
53                          return MB->getBuffer().substr(Offset, Length);
54                        },
55                        [=](bool Success) { delete MB; }});
56   return true;
57 }
58 
59 #ifdef LLVM_ENABLE_HTTPLIB
60 
61 bool HTTPServer::isAvailable() { return true; }
62 
63 HTTPServer::HTTPServer() { Server = std::make_unique<httplib::Server>(); }
64 
65 HTTPServer::~HTTPServer() { stop(); }
66 
67 static void expandUrlPathMatches(const std::smatch &Matches,
68                                  HTTPServerRequest &Request) {
69   bool UrlPathSet = false;
70   for (const auto &it : Matches) {
71     if (UrlPathSet)
72       Request.UrlPathMatches.push_back(it);
73     else {
74       Request.UrlPath = it;
75       UrlPathSet = true;
76     }
77   }
78 }
79 
80 HTTPServerRequest::HTTPServerRequest(const httplib::Request &HTTPLibRequest,
81                                      httplib::Response &HTTPLibResponse)
82     : HTTPLibResponse(HTTPLibResponse) {
83   expandUrlPathMatches(HTTPLibRequest.matches, *this);
84 }
85 
86 void HTTPServerRequest::setResponse(HTTPResponse Response) {
87   HTTPLibResponse.set_content(Response.Body.begin(), Response.Body.size(),
88                               Response.ContentType);
89   HTTPLibResponse.status = Response.Code;
90 }
91 
92 void HTTPServerRequest::setResponse(StreamingHTTPResponse Response) {
93   HTTPLibResponse.set_content_provider(
94       Response.ContentLength, Response.ContentType,
95       [=](size_t Offset, size_t Length, httplib::DataSink &Sink) {
96         if (Offset < Response.ContentLength) {
97           StringRef Chunk = Response.Provider(Offset, Length);
98           Sink.write(Chunk.begin(), Chunk.size());
99         }
100         return true;
101       },
102       [=](bool Success) { Response.CompletionHandler(Success); });
103 
104   HTTPLibResponse.status = Response.Code;
105 }
106 
107 Error HTTPServer::get(StringRef UrlPathPattern, HTTPRequestHandler Handler) {
108   std::string ErrorMessage;
109   if (!Regex(UrlPathPattern).isValid(ErrorMessage))
110     return createStringError(errc::argument_out_of_domain, ErrorMessage);
111   Server->Get(std::string(UrlPathPattern),
112               [Handler](const httplib::Request &HTTPLibRequest,
113                         httplib::Response &HTTPLibResponse) {
114                 HTTPServerRequest Request(HTTPLibRequest, HTTPLibResponse);
115                 Handler(Request);
116               });
117   return Error::success();
118 }
119 
120 Error HTTPServer::bind(unsigned ListenPort, const char *HostInterface) {
121   if (!Server->bind_to_port(HostInterface, ListenPort))
122     return createStringError(errc::io_error,
123                              "Could not assign requested address.");
124   Port = ListenPort;
125   return Error::success();
126 }
127 
128 Expected<unsigned> HTTPServer::bind(const char *HostInterface) {
129   int ListenPort = Server->bind_to_any_port(HostInterface);
130   if (ListenPort < 0)
131     return createStringError(errc::io_error,
132                              "Could not assign any port on requested address.");
133   return Port = ListenPort;
134 }
135 
136 Error HTTPServer::listen() {
137   if (!Port)
138     return createStringError(errc::io_error,
139                              "Cannot listen without first binding to a port.");
140   if (!Server->listen_after_bind())
141     return createStringError(
142         errc::io_error,
143         "An unknown error occurred when cpp-httplib attempted to listen.");
144   return Error::success();
145 }
146 
147 void HTTPServer::stop() {
148   Server->stop();
149   Port = 0;
150 }
151 
152 #else
153 
154 // TODO: Implement barebones standalone HTTP server implementation.
155 bool HTTPServer::isAvailable() { return false; }
156 
157 HTTPServer::HTTPServer() = default;
158 
159 HTTPServer::~HTTPServer() = default;
160 
161 void HTTPServerRequest::setResponse(HTTPResponse Response) {
162   llvm_unreachable("No HTTP server implementation available");
163 }
164 
165 void HTTPServerRequest::setResponse(StreamingHTTPResponse Response) {
166   llvm_unreachable("No HTTP server implementation available");
167 }
168 
169 Error HTTPServer::get(StringRef UrlPathPattern, HTTPRequestHandler Handler) {
170   llvm_unreachable("No HTTP server implementation available");
171 }
172 
173 Error HTTPServer::bind(unsigned ListenPort, const char *HostInterface) {
174   llvm_unreachable("No HTTP server implementation available");
175 }
176 
177 Expected<unsigned> HTTPServer::bind(const char *HostInterface) {
178   llvm_unreachable("No HTTP server implementation available");
179 }
180 
181 Error HTTPServer::listen() {
182   llvm_unreachable("No HTTP server implementation available");
183 }
184 
185 void HTTPServer::stop() {
186   llvm_unreachable("No HTTP server implementation available");
187 }
188 
189 #endif // LLVM_ENABLE_HTTPLIB
190