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Diffstat (limited to 'lldb/source/Utility/SelectHelper.cpp')
| -rw-r--r-- | lldb/source/Utility/SelectHelper.cpp | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/lldb/source/Utility/SelectHelper.cpp b/lldb/source/Utility/SelectHelper.cpp new file mode 100644 index 00000000000..7d616d5745a --- /dev/null +++ b/lldb/source/Utility/SelectHelper.cpp @@ -0,0 +1,294 @@ +//===-- SelectHelper.cpp ----------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#if defined(__APPLE__) +// Enable this special support for Apple builds where we can have unlimited +// select bounds. We tried switching to poll() and kqueue and we were panicing +// the kernel, so we have to stick with select for now. +#define _DARWIN_UNLIMITED_SELECT +#endif + +// C Includes +#include <errno.h> +#if defined(_WIN32) +// Define NOMINMAX to avoid macros that conflict with std::min and std::max +#define NOMINMAX +#include <winsock2.h> +#else +#include <sys/select.h> +#endif + +// C++ Includes +#include <algorithm> + +// Other libraries and framework includes +#include "llvm/ADT/SmallVector.h" + +// Project includes +#include "lldb/Core/Error.h" +#include "lldb/Utility/SelectHelper.h" +#include "lldb/Utility/LLDBAssert.h" + +SelectHelper::SelectHelper() : + m_fd_map(), + m_end_time() // Infinite timeout unless SelectHelper::SetTimeout() gets called +{ +} + +void +SelectHelper::SetTimeout(const std::chrono::microseconds &timeout) +{ + using namespace std::chrono; + m_end_time = steady_clock::time_point(steady_clock::now() + timeout); +} + +void +SelectHelper::FDSetRead(int fd) +{ + m_fd_map[fd].read_set = true; +} + +void +SelectHelper::FDSetWrite(int fd) +{ + m_fd_map[fd].write_set = true; +} + +void +SelectHelper::FDSetError(int fd) +{ + m_fd_map[fd].error_set = true; +} + +bool +SelectHelper::FDIsSetRead(int fd) const +{ + auto pos = m_fd_map.find(fd); + if (pos != m_fd_map.end()) + return pos->second.read_is_set; + else + return false; +} + +bool +SelectHelper::FDIsSetWrite(int fd) const +{ + auto pos = m_fd_map.find(fd); + if (pos != m_fd_map.end()) + return pos->second.write_is_set; + else + return false; +} + +bool +SelectHelper::FDIsSetError(int fd) const +{ + auto pos = m_fd_map.find(fd); + if (pos != m_fd_map.end()) + return pos->second.error_is_set; + else + return false; +} + +lldb_private::Error +SelectHelper::Select() +{ + lldb_private::Error error; + + int max_read_fd = -1; + int max_write_fd = -1; + int max_error_fd = -1; + int max_fd = -1; + for (auto &pair : m_fd_map) + { + pair.second.PrepareForSelect(); + const int fd = pair.first; +#if !defined(__APPLE__) + lldbassert(fd < FD_SETSIZE); + if (fd >= FD_SETSIZE) + { + error.SetErrorStringWithFormat("%i is too large for select()", fd); + return error; + } +#endif + if (pair.second.read_set) + { + max_read_fd = std::max<int>(fd, max_read_fd); + max_fd = std::max<int>(fd, max_fd); + } + if (pair.second.write_set) + { + max_write_fd = std::max<int>(fd, max_write_fd); + max_fd = std::max<int>(fd, max_fd); + } + if (pair.second.error_set) + { + max_error_fd = std::max<int>(fd, max_error_fd); + max_fd = std::max<int>(fd, max_fd); + } + } + + if (max_fd == -1) + { + error.SetErrorString("no valid file descriptors"); + return error; + } + + const int nfds = max_fd + 1; + fd_set *read_fdset_ptr = nullptr; + fd_set *write_fdset_ptr = nullptr; + fd_set *error_fdset_ptr = nullptr; + //---------------------------------------------------------------------- + // Initialize and zero out the fdsets + //---------------------------------------------------------------------- +#if defined(__APPLE__) + llvm::SmallVector<fd_set, 1> read_fdset; + llvm::SmallVector<fd_set, 1> write_fdset; + llvm::SmallVector<fd_set, 1> error_fdset; + + if (max_read_fd >= 0) + { + read_fdset.resize((nfds / FD_SETSIZE) + 1); + read_fdset_ptr = read_fdset.data(); + } + if (max_write_fd >= 0) + { + write_fdset.resize((nfds / FD_SETSIZE) + 1); + write_fdset_ptr = write_fdset.data(); + } + if (max_error_fd >= 0) + { + error_fdset.resize((nfds / FD_SETSIZE) + 1); + error_fdset_ptr = error_fdset.data(); + } + for (auto &fd_set : read_fdset) + FD_ZERO(&fd_set); + for (auto &fd_set : write_fdset) + FD_ZERO(&fd_set); + for (auto &fd_set : error_fdset) + FD_ZERO(&fd_set); +#else + fd_set read_fdset; + fd_set write_fdset; + fd_set error_fdset; + + if (max_read_fd >= 0) + { + FD_ZERO(&read_fdset); + read_fdset_ptr = &read_fdset; + } + if (max_write_fd >= 0) + { + FD_ZERO(&write_fdset); + write_fdset_ptr = &write_fdset; + } + if (max_error_fd >= 0) + { + FD_ZERO(&error_fdset); + error_fdset_ptr = &error_fdset; + } +#endif + //---------------------------------------------------------------------- + // Set the FD bits in the fdsets for read/write/error + //---------------------------------------------------------------------- + for (auto &pair : m_fd_map) + { + const int fd = pair.first; + + if (pair.second.read_set) + FD_SET(fd, read_fdset_ptr); + + if (pair.second.write_set) + FD_SET(fd, write_fdset_ptr); + + if (pair.second.error_set) + FD_SET(fd, error_fdset_ptr); + } + + //---------------------------------------------------------------------- + // Setup our timeout time value if needed + //---------------------------------------------------------------------- + struct timeval *tv_ptr = nullptr; + struct timeval tv = {0, 0}; + + while (1) + { + using namespace std::chrono; + //------------------------------------------------------------------ + // Setup out relative timeout based on the end time if we have one + //------------------------------------------------------------------ + if (m_end_time.hasValue()) + { + tv_ptr = &tv; + const auto remaining_dur = duration_cast<microseconds>(m_end_time.getValue() - steady_clock::now()); + if (remaining_dur.count() > 0) + { + // Wait for a specific amount of time + const auto dur_secs = duration_cast<seconds>(remaining_dur); + const auto dur_usecs = remaining_dur % seconds(1); + tv.tv_sec = dur_secs.count(); + tv.tv_usec = dur_usecs.count(); + } + else + { + // Just poll once with no timeout + tv.tv_sec = 0; + tv.tv_usec = 0; + } + } + const int num_set_fds = ::select(nfds, read_fdset_ptr, write_fdset_ptr, error_fdset_ptr, tv_ptr); + if (num_set_fds < 0) + { + // We got an error + error.SetErrorToErrno(); + if (error.GetError() == EINTR) + { + error.Clear(); + continue; // Keep calling select if we get EINTR + } + else + return error; + } + else if (num_set_fds == 0) + { + // Timeout + error.SetError(ETIMEDOUT, lldb::eErrorTypePOSIX); + error.SetErrorString("timed out"); + return error; + } + else + { + // One or more descriptors were set, update the FDInfo::select_is_set mask + // so users can ask the SelectHelper class so clients can call one of: + + for (auto &pair : m_fd_map) + { + const int fd = pair.first; + + if (pair.second.read_set) + { + if (FD_ISSET(fd, read_fdset_ptr)) + pair.second.read_is_set = true; + } + if (pair.second.write_set) + { + if (FD_ISSET(fd, write_fdset_ptr)) + pair.second.write_is_set = true; + } + if (pair.second.error_set) + { + if (FD_ISSET(fd, error_fdset_ptr)) + pair.second.error_is_set = true; + } + } + break; + } + } + return error; +} |
