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switch from select to poll to deal with Android 9 giving us high socket fds when calling ::connect

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This commit is contained in:
Benjamin Sergeant
2019-06-25 17:11:27 -07:00
parent 705625af0a
commit 4cbfa71338
1 changed files with 23 additions and 38 deletions
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61
ixwebsocket/IXSocket.cpp
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@@ -17,6 +17,7 @@
#include <stdint.h> #include <stdint.h>
#include <fcntl.h> #include <fcntl.h>
#include <sys/types.h> #include <sys/types.h>
#include <poll.h>
#include <algorithm> #include <algorithm>
@@ -49,25 +50,21 @@ namespace ix
int sockfd, int sockfd,
std::shared_ptr<SelectInterrupt> selectInterrupt) std::shared_ptr<SelectInterrupt> selectInterrupt)
{ {
fd_set rfds; //
fd_set wfds; // We used to use ::select to poll but on Android 9 we get large fds out of ::connect
fd_set efds; // which crash in FD_SET as they are larger than FD_SETSIZE.
FD_ZERO(&rfds); // Switching to ::poll does fix that.
FD_ZERO(&wfds); //
FD_ZERO(&efds); // However poll isn't as portable as select and has bugs on Windows, so we should write a
// shim to fallback to select on those platforms.
// See https://github.com/mpv-player/mpv/pull/5203/files for such a select wrapper.
//
int nfds = 1;
struct pollfd fds[2];
// FD_SET cannot handle fds larger than FD_SETSIZE. fds[0].fd = sockfd;
if (sockfd >= FD_SETSIZE) fds[0].events = (readyToRead) ? POLLIN : POLLOUT;
{ fds[0].events |= POLLERR;
return PollResultType::Error;
}
fd_set* fds = (readyToRead) ? &rfds : & wfds;
if (sockfd != -1)
{
FD_SET(sockfd, fds);
FD_SET(sockfd, &efds);
}
// File descriptor used to interrupt select when needed // File descriptor used to interrupt select when needed
int interruptFd = -1; int interruptFd = -1;
@@ -75,27 +72,15 @@ namespace ix
{ {
interruptFd = selectInterrupt->getFd(); interruptFd = selectInterrupt->getFd();
// FD_SET cannot handle fds larger than FD_SETSIZE.
if (interruptFd >= FD_SETSIZE)
{
return PollResultType::Error;
}
if (interruptFd != -1) if (interruptFd != -1)
{ {
FD_SET(interruptFd, fds); nfds = 2;
fds[1].fd = interruptFd;
fds[1].events = POLLIN;
} }
} }
struct timeval timeout; int ret = ::poll(fds, nfds, timeoutMs);
timeout.tv_sec = timeoutMs / 1000;
timeout.tv_usec = 1000 * (timeoutMs % 1000);
// Compute the highest fd.
int nfds = (std::max)(sockfd, interruptFd);
int ret = ::select(nfds + 1, &rfds, &wfds, &efds,
(timeoutMs < 0) ? nullptr : &timeout);
PollResultType pollResult = PollResultType::ReadyForRead; PollResultType pollResult = PollResultType::ReadyForRead;
if (ret < 0) if (ret < 0)
@@ -106,7 +91,7 @@ namespace ix
{ {
pollResult = PollResultType::Timeout; pollResult = PollResultType::Timeout;
} }
else if (interruptFd != -1 && FD_ISSET(interruptFd, &rfds)) else if (interruptFd != -1 && fds[1].revents & POLLIN)
{ {
uint64_t value = selectInterrupt->read(); uint64_t value = selectInterrupt->read();
@@ -119,17 +104,17 @@ namespace ix
pollResult = PollResultType::CloseRequest; pollResult = PollResultType::CloseRequest;
} }
} }
else if (sockfd != -1 && readyToRead && FD_ISSET(sockfd, &rfds)) else if (sockfd != -1 && readyToRead && fds[0].revents & POLLIN)
{ {
pollResult = PollResultType::ReadyForRead; pollResult = PollResultType::ReadyForRead;
} }
else if (sockfd != -1 && !readyToRead && FD_ISSET(sockfd, &wfds)) else if (sockfd != -1 && !readyToRead && fds[0].revents & POLLOUT)
{ {
pollResult = PollResultType::ReadyForWrite; pollResult = PollResultType::ReadyForWrite;
#ifdef _WIN32 #ifdef _WIN32
// On connect error, in async mode, windows will write to the exceptions fds // On connect error, in async mode, windows will write to the exceptions fds
if (FD_ISSET(fd, &efds)) if (fds[0].revents & POLLERR)
{ {
pollResult = PollResultType::Error; pollResult = PollResultType::Error;
} }