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/*
* Phusion Passenger - https://www.phusionpassenger.com/
* Copyright (c) 2011-2018 Phusion Holding B.V.
*
* "Passenger", "Phusion Passenger" and "Union Station" are registered
* trademarks of Phusion Holding B.V.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef _PASSENGER_IOTOOLS_MESSAGE_IO_H_
#define _PASSENGER_IOTOOLS_MESSAGE_IO_H_
/**
* This file contains functions for reading and writing structured messages over
* I/O channels. Supported message types are as follows.
*
* == 16-bit and 32-bit integers
* Their raw formats are binary, in big endian.
*
* == Array of strings (array messages)
* Each string may contain arbitrary data except for the NUL byte.
* Its raw format consists of a 16-bit big endian size header
* and a body containing all the strings in the array, each terminated
* by a NUL byte. The size header specifies the raw size of the body.
*
* == Arbitary binary strings (scalar messages)
* Its raw format consists of a 32-bit big endian size header
* followed by the raw string data.
*
* == File descriptor passing and negotiation
* Unix socket file descriptor passing is not safe without some kind
* of negotiation protocol. If one side passes a file descriptor, and
* the other side accidentally read()s past the normal data then it
* will read away the passed file descriptor too without actually
* receiving it.
*
* For example suppose that side A looks like this:
*
* read(fd, buf, 1024)
* read_io(fd)
*
* and side B:
*
* write(fd, buf, 100)
* send_io(fd_to_pass)
*
* If B completes both write() and send_io(), then A's read() call
* reads past the 100 bytes that B sent. On some platforms, like
* Linux, this will cause read_io() to fail. And it just so happens
* that Ruby's IO#read method slurps more than just the given amount
* of bytes.
*
* In order to solve this problem, we wrap the actual file descriptor
* passing/reading code into a negotiation protocol to ensure that
* this situation can never happen.
*/
// For ntohl/htonl/ntohs/htons.
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <algorithm>
#include <string>
#include <vector>
#include <cstring>
#include <cstdarg>
#include <boost/cstdint.hpp>
#include <boost/bind/bind.hpp>
#include <boost/scoped_array.hpp>
#include <oxt/macros.hpp>
#include <StaticString.h>
#include <Exceptions.h>
#include <SecurityKit/MemZeroGuard.h>
#include <Utils/ScopeGuard.h>
#include <IOTools/IOUtils.h>
#include <StrIntTools/StrIntUtils.h>
namespace Passenger {
using namespace std;
using namespace boost;
/**
* Reads a 16-bit unsigned integer from the given file descriptor. The result
* is put into 'output'.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @return True if reading was successful, false if end-of-file was prematurely reached.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline bool
readUint16(int fd, boost::uint16_t &output, unsigned long long *timeout = NULL) {
boost::uint16_t temp;
if (readExact(fd, &temp, sizeof(boost::uint16_t), timeout) == sizeof(boost::uint16_t)) {
output = ntohs(temp);
return true;
} else {
return false;
}
}
/**
* Reads a 16-bit unsigned integer from the given file descriptor.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws EOFException End-of-file was reached before a full integer could be read.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline boost::uint16_t
readUint16(int fd, unsigned long long *timeout = NULL) {
boost::uint16_t temp;
if (readUint16(fd, temp, timeout)) {
return temp;
} else {
throw EOFException("EOF encountered before a full 16-bit integer could be read");
}
}
/**
* Reads a 32-bit unsigned integer from the given file descriptor. The result
* is put into 'output'.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @return True if reading was successful, false if end-of-file was prematurely reached.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline bool
readUint32(int fd, boost::uint32_t &output, unsigned long long *timeout = NULL) {
boost::uint32_t temp;
if (readExact(fd, &temp, sizeof(boost::uint32_t), timeout) == sizeof(boost::uint32_t)) {
output = ntohl(temp);
return true;
} else {
return false;
}
}
/**
* Reads a 32-bit unsigned integer from the given file descriptor.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws EOFException End-of-file was reached before a full integer could be read.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline boost::uint32_t
readUint32(int fd, unsigned long long *timeout = NULL) {
boost::uint32_t temp;
if (readUint32(fd, temp, timeout)) {
return temp;
} else {
throw EOFException("EOF encountered before a full 32-bit integer could be read");
}
}
/**
* Reads an array message from the given file descriptor. This version
* puts the result into the given collection instead of returning a
* new collection.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @return True if an array message was read, false if end-of-file was reached
* before a full array message could be read.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
template<typename Collection>
inline bool
readArrayMessage(int fd, Collection &output, unsigned long long *timeout = NULL) {
boost::uint16_t size;
if (!readUint16(fd, size, timeout)) {
return false;
}
scoped_array<char> buffer(new char[size]);
MemZeroGuard g(buffer.get(), size);
if (readExact(fd, buffer.get(), size, timeout) != size) {
return false;
}
output.clear();
if (size != 0) {
string::size_type start = 0, pos;
StaticString buffer_str(buffer.get(), size);
while ((pos = buffer_str.find('\0', start)) != string::npos) {
output.push_back(buffer_str.substr(start, pos - start));
start = pos + 1;
}
}
return true;
}
/**
* Reads an array message from the given file descriptor. This version returns
* the result immediately as a string vector.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws EOFException End-of-file was reached before a full integer could be read.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline vector<string>
readArrayMessage(int fd, unsigned long long *timeout = NULL) {
vector<string> output;
if (readArrayMessage(fd, output, timeout)) {
return output;
} else {
throw EOFException("EOF encountered before the full array message could be read");
}
}
/**
* Reads a scalar message from the given file descriptor.
*
* @param maxSize The maximum number of bytes that may be read. If the
* scalar to read is larger than this, then a SecurityException
* will be thrown. Set to 0 for no size limit.
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @return True if a scalar message was read, false if EOF was encountered.
* @throws SystemException Something went wrong.
* @throws SecurityException The message body is larger than allowed by maxSize.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline bool
readScalarMessage(int fd, string &output, unsigned int maxSize = 0, unsigned long long *timeout = NULL) {
boost::uint32_t size;
if (!readUint32(fd, size, timeout)) {
return false;
}
if (maxSize != 0 && size > (boost::uint32_t) maxSize) {
throw SecurityException("The scalar message body is larger than the size limit");
}
unsigned int remaining = size;
if (OXT_UNLIKELY(!output.empty())) {
output.clear();
}
output.reserve(size);
if (OXT_LIKELY(remaining > 0)) {
char buf[1024 * 32];
MemZeroGuard g(buf, sizeof(buf));
while (remaining > 0) {
unsigned int blockSize = min((unsigned int) sizeof(buf), remaining);
if (readExact(fd, buf, blockSize, timeout) != blockSize) {
return false;
}
output.append(buf, blockSize);
remaining -= blockSize;
}
}
return true;
}
/**
* Reads a scalar message from the given file descriptor.
*
* @param maxSize The maximum number of bytes that may be read. If the
* scalar to read is larger than this, then a SecurityException
* will be thrown. Set to 0 for no size limit.
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on reading the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on reading will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws EOFException End-of-file was reached before a full integer could be read.
* @throws SystemException Something went wrong.
* @throws SecurityException The message body is larger than allowed by maxSize.
* @throws TimeoutException Unable to read the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline string
readScalarMessage(int fd, unsigned int maxSize = 0, unsigned long long *timeout = NULL) {
string output;
if (readScalarMessage(fd, output, maxSize, timeout)) {
return output;
} else {
throw EOFException("EOF encountered before a full scalar message could be read");
}
}
/**
* Writes a 16-bit unsigned integer to the given file descriptor.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on writing the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on writing will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to write the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline void
writeUint16(int fd, boost::uint16_t value, unsigned long long *timeout = NULL) {
boost::uint16_t l = htons(value);
writeExact(fd, &l, sizeof(boost::uint16_t), timeout);
}
/**
* Writes a 32-bit unsigned integer to the given file descriptor.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on writing the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on writing will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to write the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline void
writeUint32(int fd, boost::uint32_t value, unsigned long long *timeout = NULL) {
boost::uint32_t l = htonl(value);
writeExact(fd, &l, sizeof(boost::uint32_t), timeout);
}
/**
* Writes an array message to the given file descriptor.
*
* @param args A collection of strings containing the array message's elements.
* The collection must have an STL container-like interface and
* the strings must have an STL string-like interface.
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on writing the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on writing will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to write the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
template<typename Collection>
inline void
writeArrayMessageEx(int fd, const Collection &args, unsigned long long *timeout = NULL) {
typename Collection::const_iterator it, end = args.end();
boost::uint16_t bodySize = 0;
for (it = args.begin(); it != end; it++) {
bodySize += it->size() + 1;
}
scoped_array<char> data(new char[sizeof(boost::uint16_t) + bodySize]);
boost::uint16_t header = htons(bodySize);
memcpy(data.get(), &header, sizeof(boost::uint16_t));
char *dataEnd = data.get() + sizeof(boost::uint16_t);
for (it = args.begin(); it != end; it++) {
memcpy(dataEnd, it->data(), it->size());
dataEnd += it->size();
*dataEnd = '\0';
dataEnd++;
}
writeExact(fd, data.get(), sizeof(boost::uint16_t) + bodySize, timeout);
}
inline void
writeArrayMessage(int fd, const vector<StaticString> &args, unsigned long long *timeout = NULL) {
writeArrayMessageEx(fd, args, timeout);
}
inline void
writeArrayMessage(int fd, const vector<string> &args, unsigned long long *timeout = NULL) {
writeArrayMessageEx(fd, args, timeout);
}
inline void
writeArrayMessage(int fd, const StaticString args[], unsigned int nargs, unsigned long long *timeout = NULL) {
unsigned int i;
boost::uint16_t bodySize = 0;
for (i = 0; i < nargs; i++) {
bodySize += args[i].size() + 1;
}
scoped_array<char> data(new char[sizeof(boost::uint16_t) + bodySize]);
boost::uint16_t header = htons(bodySize);
memcpy(data.get(), &header, sizeof(boost::uint16_t));
char *dataEnd = data.get() + sizeof(boost::uint16_t);
for (i = 0; i < nargs; i++) {
memcpy(dataEnd, args[i].data(), args[i].size());
dataEnd += args[i].size();
*dataEnd = '\0';
dataEnd++;
}
writeExact(fd, data.get(), sizeof(boost::uint16_t) + bodySize, timeout);
}
inline void
writeArrayMessageVA(int fd, const StaticString &name, va_list &ap, unsigned long long *timeout = NULL) {
StaticString args[10];
unsigned int nargs = 1;
bool done = false;
args[0] = name;
do {
const char *arg = va_arg(ap, const char *);
if (arg == NULL) {
done = true;
} else {
args[nargs] = arg;
nargs++;
}
} while (!done && nargs < sizeof(args) / sizeof(StaticString));
if (done) {
writeArrayMessage(fd, args, nargs, timeout);
} else {
// Arguments don't fit in static array. Use dynamic
// array instead.
vector<StaticString> dyn_args;
for (unsigned int i = 0; i < nargs; i++) {
dyn_args.push_back(args[i]);
}
do {
const char *arg = va_arg(ap, const char *);
if (arg == NULL) {
done = true;
} else {
dyn_args.push_back(arg);
}
} while (!done);
writeArrayMessage(fd, dyn_args, timeout);
}
}
struct _VaGuard {
va_list ≈
_VaGuard(va_list &_ap)
: ap(_ap)
{ }
~_VaGuard() {
va_end(ap);
}
};
/** Version of writeArrayMessage() that accepts a variadic list of 'const char *'
* arguments as message elements. The list must be terminated with a NULL.
*/
inline void
writeArrayMessage(int fd, const char *name, ...) {
va_list ap;
va_start(ap, name);
_VaGuard guard(ap);
writeArrayMessageVA(fd, name, ap);
}
/** Version of writeArrayMessage() that accepts a variadic list of 'const char *'
* arguments as message elements, with timeout support. The list must be terminated
* with a NULL.
*/
inline void
writeArrayMessage(int fd, unsigned long long *timeout, const char *name, ...) {
va_list ap;
va_start(ap, name);
_VaGuard guard(ap);
writeArrayMessageVA(fd, name, ap, timeout);
}
/**
* Writes a scalar message to the given file descriptor.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on writing the necessary data.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on writing will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to write the necessary data within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline void
writeScalarMessage(int fd, const StaticString &data, unsigned long long *timeout = NULL) {
boost::uint32_t header = htonl(data.size());
StaticString buffers[2] = {
StaticString((const char *) &header, sizeof(boost::uint32_t)),
data
};
gatheredWrite(fd, buffers, 2, timeout);
}
inline void
writeScalarMessage(int fd, const char *data, size_t size, unsigned long long *timeout = NULL) {
writeScalarMessage(fd, StaticString(data, size), timeout);
}
/**
* Receive a file descriptor over the given Unix domain socket,
* involving a negotiation protocol.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on receiving the file descriptor.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on receiving will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @return The received file descriptor.
* @throws SystemException Something went wrong.
* @throws IOException Whatever was received doesn't seem to be a
* file descriptor.
* @throws TimeoutException Unable to receive a file descriptor within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline int
readFileDescriptorWithNegotiation(int fd, unsigned long long *timeout = NULL) {
writeArrayMessage(fd, timeout, "pass IO", NULL);
int result = readFileDescriptor(fd, timeout);
ScopeGuard guard(boost::bind(safelyClose, result, false));
writeArrayMessage(fd, timeout, "got IO", NULL);
guard.clear();
return result;
}
/**
* Pass the file descriptor 'fdToSend' over the Unix socket 'fd',
* involving a negotiation protocol.
*
* @param timeout A pointer to an integer, which specifies the maximum number of
* microseconds that may be spent on trying to pass the file descriptor.
* If the timeout expired then TimeoutException will be thrown.
* If this function returns without throwing an exception, then the
* total number of microseconds spent on writing will be deducted
* from <tt>timeout</tt>.
* Pass NULL if you do not want to enforce a timeout.
* @throws SystemException Something went wrong.
* @throws TimeoutException Unable to pass the file descriptor within
* <tt>timeout</tt> microseconds.
* @throws boost::thread_interrupted
*/
inline void
writeFileDescriptorWithNegotiation(int fd, int fdToPass, unsigned long long *timeout = NULL) {
vector<string> args;
args = readArrayMessage(fd, timeout);
if (args.size() != 1 || args[0] != "pass IO") {
throw IOException("FD passing pre-negotiation message expected");
}
writeFileDescriptor(fd, fdToPass, timeout);
args = readArrayMessage(fd, timeout);
if (args.size() != 1 || args[0] != "got IO") {
throw IOException("FD passing post-negotiation message expected.");
}
}
} // namespace Passenger
#endif /* _PASSENGER_IOTOOLS_MESSAGE_IO_H_ */
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