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//
// Copyright (C) 2012 The Android Open Source Project
//
// 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.
//
// This file implements a simple HTTP server. It can exhibit odd behavior
// that's useful for testing. For example, it's useful to test that
// the updater can continue a connection if it's dropped, or that it
// handles very slow data transfers.
// To use this, simply make an HTTP connection to localhost:port and
// GET a url.
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <netinet/in.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <string>
#include <vector>
#include <base/logging.h>
#include <base/strings/string_split.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
#include "update_engine/http_common.h"
// HTTP end-of-line delimiter; sorry, this needs to be a macro.
#define EOL "\r\n"
using std::string;
using std::vector;
namespace chromeos_update_engine {
static const char* kListeningMsgPrefix = "listening on port ";
enum {
RC_OK = 0,
RC_BAD_ARGS,
RC_ERR_READ,
RC_ERR_SETSOCKOPT,
RC_ERR_BIND,
RC_ERR_LISTEN,
RC_ERR_GETSOCKNAME,
RC_ERR_REPORT,
};
struct HttpRequest {
HttpRequest()
: start_offset(0), end_offset(0), return_code(kHttpResponseOk) {}
string host;
string url;
off_t start_offset;
off_t end_offset; // non-inclusive, zero indicates unspecified.
HttpResponseCode return_code;
};
bool ParseRequest(int fd, HttpRequest* request) {
string headers;
do {
char buf[1024];
ssize_t r = read(fd, buf, sizeof(buf));
if (r < 0) {
perror("read");
exit(RC_ERR_READ);
}
headers.append(buf, r);
} while (!base::EndsWith(headers, EOL EOL, true));
LOG(INFO) << "got headers:\n--8<------8<------8<------8<----\n"
<< headers
<< "\n--8<------8<------8<------8<----";
// Break header into lines.
vector<string> lines;
base::SplitStringUsingSubstr(
headers.substr(0, headers.length() - strlen(EOL EOL)), EOL, &lines);
// Decode URL line.
vector<string> terms;
base::SplitStringAlongWhitespace(lines[0], &terms);
CHECK_EQ(terms.size(), static_cast<vector<string>::size_type>(3));
CHECK_EQ(terms[0], "GET");
request->url = terms[1];
LOG(INFO) << "URL: " << request->url;
// Decode remaining lines.
size_t i;
for (i = 1; i < lines.size(); i++) {
vector<string> terms;
base::SplitStringAlongWhitespace(lines[i], &terms);
if (terms[0] == "Range:") {
CHECK_EQ(terms.size(), static_cast<vector<string>::size_type>(2));
string &range = terms[1];
LOG(INFO) << "range attribute: " << range;
CHECK(base::StartsWithASCII(range, "bytes=", true) &&
range.find('-') != string::npos);
request->start_offset = atoll(range.c_str() + strlen("bytes="));
// Decode end offset and increment it by one (so it is non-inclusive).
if (range.find('-') < range.length() - 1)
request->end_offset = atoll(range.c_str() + range.find('-') + 1) + 1;
request->return_code = kHttpResponsePartialContent;
string tmp_str = base::StringPrintf("decoded range offsets: "
"start=%jd end=",
(intmax_t)request->start_offset);
if (request->end_offset > 0)
base::StringAppendF(&tmp_str, "%jd (non-inclusive)",
(intmax_t)request->end_offset);
else
base::StringAppendF(&tmp_str, "unspecified");
LOG(INFO) << tmp_str;
} else if (terms[0] == "Host:") {
CHECK_EQ(terms.size(), static_cast<vector<string>::size_type>(2));
request->host = terms[1];
LOG(INFO) << "host attribute: " << request->host;
} else {
LOG(WARNING) << "ignoring HTTP attribute: `" << lines[i] << "'";
}
}
return true;
}
string Itoa(off_t num) {
char buf[100] = {0};
snprintf(buf, sizeof(buf), "%" PRIi64, num);
return buf;
}
// Writes a string into a file. Returns total number of bytes written or -1 if a
// write error occurred.
ssize_t WriteString(int fd, const string& str) {
const size_t total_size = str.size();
size_t remaining_size = total_size;
char const *data = str.data();
while (remaining_size) {
ssize_t written = write(fd, data, remaining_size);
if (written < 0) {
perror("write");
LOG(INFO) << "write failed";
return -1;
}
data += written;
remaining_size -= written;
}
return total_size;
}
// Writes the headers of an HTTP response into a file.
ssize_t WriteHeaders(int fd, const off_t start_offset, const off_t end_offset,
HttpResponseCode return_code) {
ssize_t written = 0, ret;
ret = WriteString(fd,
string("HTTP/1.1 ") + Itoa(return_code) + " " +
GetHttpResponseDescription(return_code) +
EOL
"Content-Type: application/octet-stream" EOL);
if (ret < 0)
return -1;
written += ret;
// Compute content legnth.
const off_t content_length = end_offset - start_offset;;
// A start offset that equals the end offset indicates that the response
// should contain the full range of bytes in the requested resource.
if (start_offset || start_offset == end_offset) {
ret = WriteString(fd,
string("Accept-Ranges: bytes" EOL
"Content-Range: bytes ") +
Itoa(start_offset == end_offset ? 0 : start_offset) +
"-" + Itoa(end_offset - 1) + "/" + Itoa(end_offset) +
EOL);
if (ret < 0)
return -1;
written += ret;
}
ret = WriteString(fd, string("Content-Length: ") + Itoa(content_length) +
EOL EOL);
if (ret < 0)
return -1;
written += ret;
return written;
}
// Writes a predetermined payload of lines of ascending bytes to a file. The
// first byte of output is appropriately offset with respect to the request line
// length. Returns the number of successfully written bytes.
size_t WritePayload(int fd, const off_t start_offset, const off_t end_offset,
const char first_byte, const size_t line_len) {
CHECK_LE(start_offset, end_offset);
CHECK_GT(line_len, static_cast<size_t>(0));
LOG(INFO) << "writing payload: " << line_len << "-byte lines starting with `"
<< first_byte << "', offset range " << start_offset << " -> "
<< end_offset;
// Populate line of ascending characters.
string line;
line.reserve(line_len);
char byte = first_byte;
size_t i;
for (i = 0; i < line_len; i++)
line += byte++;
const size_t total_len = end_offset - start_offset;
size_t remaining_len = total_len;
bool success = true;
// If start offset is not aligned with line boundary, output partial line up
// to the first line boundary.
size_t start_modulo = start_offset % line_len;
if (start_modulo) {
string partial = line.substr(start_modulo, remaining_len);
ssize_t ret = WriteString(fd, partial);
if ((success = (ret >= 0 && (size_t) ret == partial.length())))
remaining_len -= partial.length();
}
// Output full lines up to the maximal line boundary below the end offset.
while (success && remaining_len >= line_len) {
ssize_t ret = WriteString(fd, line);
if ((success = (ret >= 0 && (size_t) ret == line_len)))
remaining_len -= line_len;
}
// Output a partial line up to the end offset.
if (success && remaining_len) {
string partial = line.substr(0, remaining_len);
ssize_t ret = WriteString(fd, partial);
if ((success = (ret >= 0 && (size_t) ret == partial.length())))
remaining_len -= partial.length();
}
return (total_len - remaining_len);
}
// Write default payload lines of the form 'abcdefghij'.
inline size_t WritePayload(int fd, const off_t start_offset,
const off_t end_offset) {
return WritePayload(fd, start_offset, end_offset, 'a', 10);
}
// Send an empty response, then kill the server.
void HandleQuit(int fd) {
WriteHeaders(fd, 0, 0, kHttpResponseOk);
LOG(INFO) << "pid(" << getpid() << "): HTTP server exiting ...";
exit(RC_OK);
}
// Generates an HTTP response with payload corresponding to requested offsets
// and length. Optionally, truncate the payload at a given length and add a
// pause midway through the transfer. Returns the total number of bytes
// delivered or -1 for error.
ssize_t HandleGet(int fd, const HttpRequest& request, const size_t total_length,
const size_t truncate_length, const int sleep_every,
const int sleep_secs) {
ssize_t ret;
size_t written = 0;
// Obtain start offset, make sure it is within total payload length.
const size_t start_offset = request.start_offset;
if (start_offset >= total_length) {
LOG(WARNING) << "start offset (" << start_offset
<< ") exceeds total length (" << total_length
<< "), generating error response ("
<< kHttpResponseReqRangeNotSat << ")";
return WriteHeaders(fd, total_length, total_length,
kHttpResponseReqRangeNotSat);
}
// Obtain end offset, adjust to fit in total payload length and ensure it does
// not preceded the start offset.
size_t end_offset = (request.end_offset > 0 ?
request.end_offset : total_length);
if (end_offset < start_offset) {
LOG(WARNING) << "end offset (" << end_offset << ") precedes start offset ("
<< start_offset << "), generating error response";
return WriteHeaders(fd, 0, 0, kHttpResponseBadRequest);
}
if (end_offset > total_length) {
LOG(INFO) << "requested end offset (" << end_offset
<< ") exceeds total length (" << total_length << "), adjusting";
end_offset = total_length;
}
// Generate headers
LOG(INFO) << "generating response header: range=" << start_offset << "-"
<< (end_offset - 1) << "/" << (end_offset - start_offset)
<< ", return code=" << request.return_code;
if ((ret = WriteHeaders(fd, start_offset, end_offset,
request.return_code)) < 0)
return -1;
LOG(INFO) << ret << " header bytes written";
written += ret;
// Compute payload length, truncate as necessary.
size_t payload_length = end_offset - start_offset;
if (truncate_length > 0 && truncate_length < payload_length) {
LOG(INFO) << "truncating request payload length (" << payload_length
<< ") at " << truncate_length;
payload_length = truncate_length;
end_offset = start_offset + payload_length;
}
LOG(INFO) << "generating response payload: range=" << start_offset << "-"
<< (end_offset - 1) << "/" << (end_offset - start_offset);
// Decide about optional midway delay.
if (truncate_length > 0 && sleep_every > 0 && sleep_secs >= 0 &&
start_offset % (truncate_length * sleep_every) == 0) {
const off_t midway_offset = start_offset + payload_length / 2;
if ((ret = WritePayload(fd, start_offset, midway_offset)) < 0)
return -1;
LOG(INFO) << ret << " payload bytes written (first chunk)";
written += ret;
LOG(INFO) << "sleeping for " << sleep_secs << " seconds...";
sleep(sleep_secs);
if ((ret = WritePayload(fd, midway_offset, end_offset)) < 0)
return -1;
LOG(INFO) << ret << " payload bytes written (second chunk)";
written += ret;
} else {
if ((ret = WritePayload(fd, start_offset, end_offset)) < 0)
return -1;
LOG(INFO) << ret << " payload bytes written";
written += ret;
}
LOG(INFO) << "response generation complete, " << written
<< " total bytes written";
return written;
}
ssize_t HandleGet(int fd, const HttpRequest& request,
const size_t total_length) {
return HandleGet(fd, request, total_length, 0, 0, 0);
}
// Handles /redirect/<code>/<url> requests by returning the specified
// redirect <code> with a location pointing to /<url>.
void HandleRedirect(int fd, const HttpRequest& request) {
LOG(INFO) << "Redirecting...";
string url = request.url;
CHECK_EQ(static_cast<size_t>(0), url.find("/redirect/"));
url.erase(0, strlen("/redirect/"));
string::size_type url_start = url.find('/');
CHECK_NE(url_start, string::npos);
HttpResponseCode code = StringToHttpResponseCode(url.c_str());
url.erase(0, url_start);
url = "http://" + request.host + url;
const char *status = GetHttpResponseDescription(code);
if (!status)
CHECK(false) << "Unrecognized redirection code: " << code;
LOG(INFO) << "Code: " << code << " " << status;
LOG(INFO) << "New URL: " << url;
ssize_t ret;
if ((ret = WriteString(fd, "HTTP/1.1 " + Itoa(code) + " " +
status + EOL)) < 0)
return;
WriteString(fd, "Location: " + url + EOL);
}
// Generate a page not found error response with actual text payload. Return
// number of bytes written or -1 for error.
ssize_t HandleError(int fd, const HttpRequest& request) {
LOG(INFO) << "Generating error HTTP response";
ssize_t ret;
size_t written = 0;
const string data("This is an error page.");
if ((ret = WriteHeaders(fd, 0, data.size(), kHttpResponseNotFound)) < 0)
return -1;
written += ret;
if ((ret = WriteString(fd, data)) < 0)
return -1;
written += ret;
return written;
}
// Generate an error response if the requested offset is nonzero, up to a given
// maximal number of successive failures. The error generated is an "Internal
// Server Error" (500).
ssize_t HandleErrorIfOffset(int fd, const HttpRequest& request,
size_t end_offset, int max_fails) {
static int num_fails = 0;
if (request.start_offset > 0 && num_fails < max_fails) {
LOG(INFO) << "Generating error HTTP response";
ssize_t ret;
size_t written = 0;
const string data("This is an error page.");
if ((ret = WriteHeaders(fd, 0, data.size(),
kHttpResponseInternalServerError)) < 0)
return -1;
written += ret;
if ((ret = WriteString(fd, data)) < 0)
return -1;
written += ret;
num_fails++;
return written;
} else {
num_fails = 0;
return HandleGet(fd, request, end_offset);
}
}
void HandleDefault(int fd, const HttpRequest& request) {
const off_t start_offset = request.start_offset;
const string data("unhandled path");
const size_t size = data.size();
ssize_t ret;
if ((ret = WriteHeaders(fd, start_offset, size, request.return_code)) < 0)
return;
WriteString(fd, (start_offset < static_cast<off_t>(size) ?
data.substr(start_offset) : ""));
}
// Break a URL into terms delimited by slashes.
class UrlTerms {
public:
UrlTerms(const string &url, size_t num_terms) {
// URL must be non-empty and start with a slash.
CHECK_GT(url.size(), static_cast<size_t>(0));
CHECK_EQ(url[0], '/');
// Split it into terms delimited by slashes, omitting the preceeding slash.
base::SplitStringDontTrim(url.substr(1), '/', &terms);
// Ensure expected length.
CHECK_EQ(terms.size(), num_terms);
}
inline string Get(const off_t index) const {
return terms[index];
}
inline const char *GetCStr(const off_t index) const {
return Get(index).c_str();
}
inline int GetInt(const off_t index) const {
return atoi(GetCStr(index));
}
inline size_t GetSizeT(const off_t index) const {
return static_cast<size_t>(atol(GetCStr(index)));
}
private:
vector<string> terms;
};
void HandleConnection(int fd) {
HttpRequest request;
ParseRequest(fd, &request);
string &url = request.url;
LOG(INFO) << "pid(" << getpid() << "): handling url " << url;
if (url == "/quitquitquit") {
HandleQuit(fd);
} else if (base::StartsWithASCII(url, "/download/", true)) {
const UrlTerms terms(url, 2);
HandleGet(fd, request, terms.GetSizeT(1));
} else if (base::StartsWithASCII(url, "/flaky/", true)) {
const UrlTerms terms(url, 5);
HandleGet(fd, request, terms.GetSizeT(1), terms.GetSizeT(2),
terms.GetInt(3), terms.GetInt(4));
} else if (url.find("/redirect/") == 0) {
HandleRedirect(fd, request);
} else if (url == "/error") {
HandleError(fd, request);
} else if (base::StartsWithASCII(url, "/error-if-offset/", true)) {
const UrlTerms terms(url, 3);
HandleErrorIfOffset(fd, request, terms.GetSizeT(1), terms.GetInt(2));
} else {
HandleDefault(fd, request);
}
close(fd);
}
} // namespace chromeos_update_engine
using namespace chromeos_update_engine; // NOLINT(build/namespaces)
void usage(const char *prog_arg) {
fprintf(
stderr,
"Usage: %s [ FILE ]\n"
"Once accepting connections, the following is written to FILE (or "
"stdout):\n"
"\"%sN\" (where N is an integer port number)\n",
basename(prog_arg), kListeningMsgPrefix);
}
int main(int argc, char** argv) {
// Check invocation.
if (argc > 2)
errx(RC_BAD_ARGS, "unexpected number of arguments (use -h for usage)");
// Parse (optional) argument.
int report_fd = STDOUT_FILENO;
if (argc == 2) {
if (!strcmp(argv[1], "-h")) {
usage(argv[0]);
exit(RC_OK);
}
report_fd = open(argv[1], O_WRONLY | O_CREAT, 00644);
}
// Ignore SIGPIPE on write() to sockets.
signal(SIGPIPE, SIG_IGN);
int listen_fd = socket(AF_INET, SOCK_STREAM, 0);
if (listen_fd < 0)
LOG(FATAL) << "socket() failed";
struct sockaddr_in server_addr = sockaddr_in();
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = 0;
{
// Get rid of "Address in use" error
int tr = 1;
if (setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &tr,
sizeof(int)) == -1) {
perror("setsockopt");
exit(RC_ERR_SETSOCKOPT);
}
}
// Bind the socket and set for listening.
if (bind(listen_fd, reinterpret_cast<struct sockaddr *>(&server_addr),
sizeof(server_addr)) < 0) {
perror("bind");
exit(RC_ERR_BIND);
}
if (listen(listen_fd, 5) < 0) {
perror("listen");
exit(RC_ERR_LISTEN);
}
// Check the actual port.
struct sockaddr_in bound_addr = sockaddr_in();
socklen_t bound_addr_len = sizeof(bound_addr);
if (getsockname(listen_fd, reinterpret_cast<struct sockaddr*>(&bound_addr),
&bound_addr_len) < 0) {
perror("getsockname");
exit(RC_ERR_GETSOCKNAME);
}
in_port_t port = ntohs(bound_addr.sin_port);
// Output the listening port, indicating that the server is processing
// requests. IMPORTANT! (a) the format of this message is as expected by some
// unit tests, avoid unilateral changes; (b) it is necessary to flush/sync the
// file to prevent the spawning process from waiting indefinitely for this
// message.
string listening_msg = base::StringPrintf("%s%hu", kListeningMsgPrefix, port);
LOG(INFO) << listening_msg;
CHECK_EQ(write(report_fd, listening_msg.c_str(), listening_msg.length()),
static_cast<int>(listening_msg.length()));
CHECK_EQ(write(report_fd, "\n", 1), 1);
if (report_fd == STDOUT_FILENO)
fsync(report_fd);
else
close(report_fd);
while (1) {
LOG(INFO) << "pid(" << getpid() << "): waiting to accept new connection";
int client_fd = accept(listen_fd, nullptr, nullptr);
LOG(INFO) << "got past accept";
if (client_fd < 0)
LOG(FATAL) << "ERROR on accept";
HandleConnection(client_fd);
}
return 0;
}