1 files changed, 221 insertions, 0 deletions
diff --git a/contrib/llvm-project/lldb/source/Host/common/PseudoTerminal.cpp b/contrib/llvm-project/lldb/source/Host/common/PseudoTerminal.cpp
new file mode 100644
index 000000000000..d53327973eb2
--- /dev/null
+++ b/contrib/llvm-project/lldb/source/Host/common/PseudoTerminal.cpp
@@ -0,0 +1,221 @@
+//===-- PseudoTerminal.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/PseudoTerminal.h"
+#include "lldb/Host/Config.h"
+#include "lldb/Host/FileSystem.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/Errno.h"
+#include <cassert>
+#include <climits>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <mutex>
+#if defined(TIOCSCTTY)
+#include <sys/ioctl.h>
+#endif
+
+#include "lldb/Host/PosixApi.h"
+
+#if defined(__APPLE__)
+#include <Availability.h>
+#endif
+
+#if defined(__ANDROID__)
+int posix_openpt(int flags);
+#endif
+
+using namespace lldb_private;
+
+// PseudoTerminal constructor
+PseudoTerminal::PseudoTerminal() = default;
+
+// Destructor
+//
+// The destructor will close the primary and secondary file descriptors if they
+// are valid and ownership has not been released using the
+// ReleasePrimaryFileDescriptor() or the ReleaseSaveFileDescriptor() member
+// functions.
+PseudoTerminal::~PseudoTerminal() {
+  ClosePrimaryFileDescriptor();
+  CloseSecondaryFileDescriptor();
+}
+
+// Close the primary file descriptor if it is valid.
+void PseudoTerminal::ClosePrimaryFileDescriptor() {
+  if (m_primary_fd >= 0) {
+    ::close(m_primary_fd);
+    m_primary_fd = invalid_fd;
+  }
+}
+
+// Close the secondary file descriptor if it is valid.
+void PseudoTerminal::CloseSecondaryFileDescriptor() {
+  if (m_secondary_fd >= 0) {
+    ::close(m_secondary_fd);
+    m_secondary_fd = invalid_fd;
+  }
+}
+
+llvm::Error PseudoTerminal::OpenFirstAvailablePrimary(int oflag) {
+#if LLDB_ENABLE_POSIX
+  // Open the primary side of a pseudo terminal
+  m_primary_fd = ::posix_openpt(oflag);
+  if (m_primary_fd < 0) {
+    return llvm::errorCodeToError(
+        std::error_code(errno, std::generic_category()));
+  }
+
+  // Grant access to the secondary pseudo terminal
+  if (::grantpt(m_primary_fd) < 0) {
+    std::error_code EC(errno, std::generic_category());
+    ClosePrimaryFileDescriptor();
+    return llvm::errorCodeToError(EC);
+  }
+
+  // Clear the lock flag on the secondary pseudo terminal
+  if (::unlockpt(m_primary_fd) < 0) {
+    std::error_code EC(errno, std::generic_category());
+    ClosePrimaryFileDescriptor();
+    return llvm::errorCodeToError(EC);
+  }
+
+  return llvm::Error::success();
+#else
+  return llvm::errorCodeToError(llvm::errc::not_supported);
+#endif
+}
+
+llvm::Error PseudoTerminal::OpenSecondary(int oflag) {
+  CloseSecondaryFileDescriptor();
+
+  std::string name = GetSecondaryName();
+  m_secondary_fd = FileSystem::Instance().Open(name.c_str(), oflag);
+  if (m_secondary_fd >= 0)
+    return llvm::Error::success();
+
+  return llvm::errorCodeToError(
+      std::error_code(errno, std::generic_category()));
+}
+
+#if !HAVE_PTSNAME_R || defined(__APPLE__)
+static std::string use_ptsname(int fd) {
+  static std::mutex mutex;
+  std::lock_guard<std::mutex> guard(mutex);
+  const char *r = ptsname(fd);
+  assert(r != nullptr);
+  return r;
+}
+#endif
+
+std::string PseudoTerminal::GetSecondaryName() const {
+  assert(m_primary_fd >= 0);
+#if HAVE_PTSNAME_R
+#if defined(__APPLE__)
+  if (__builtin_available(macos 10.13.4, iOS 11.3, tvOS 11.3, watchOS 4.4, *)) {
+#endif
+    char buf[PATH_MAX];
+    buf[0] = '\0';
+    int r = ptsname_r(m_primary_fd, buf, sizeof(buf));
+    UNUSED_IF_ASSERT_DISABLED(r);
+    assert(r == 0);
+    return buf;
+#if defined(__APPLE__)
+  } else {
+    return use_ptsname(m_primary_fd);
+  }
+#endif
+#else
+  return use_ptsname(m_primary_fd);
+#endif
+}
+
+llvm::Expected<lldb::pid_t> PseudoTerminal::Fork() {
+#if LLDB_ENABLE_POSIX
+  if (llvm::Error Err = OpenFirstAvailablePrimary(O_RDWR | O_CLOEXEC))
+    return std::move(Err);
+
+  pid_t pid = ::fork();
+  if (pid < 0) {
+    return llvm::errorCodeToError(
+        std::error_code(errno, std::generic_category()));
+  }
+  if (pid > 0) {
+    // Parent process.
+    return pid;
+  }
+
+  // Child Process
+  ::setsid();
+
+  if (llvm::Error Err = OpenSecondary(O_RDWR))
+    return std::move(Err);
+
+  // Primary FD should have O_CLOEXEC set, but let's close it just in
+  // case...
+  ClosePrimaryFileDescriptor();
+
+#if defined(TIOCSCTTY)
+  // Acquire the controlling terminal
+  if (::ioctl(m_secondary_fd, TIOCSCTTY, (char *)0) < 0) {
+    return llvm::errorCodeToError(
+        std::error_code(errno, std::generic_category()));
+  }
+#endif
+  // Duplicate all stdio file descriptors to the secondary pseudo terminal
+  for (int fd : {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO}) {
+    if (::dup2(m_secondary_fd, fd) != fd) {
+      return llvm::errorCodeToError(
+          std::error_code(errno, std::generic_category()));
+    }
+  }
+#endif
+  return 0;
+}
+
+// The primary file descriptor accessor. This object retains ownership of the
+// primary file descriptor when this accessor is used. Use
+// ReleasePrimaryFileDescriptor() if you wish this object to release ownership
+// of the primary file descriptor.
+//
+// Returns the primary file descriptor, or -1 if the primary file descriptor is
+// not currently valid.
+int PseudoTerminal::GetPrimaryFileDescriptor() const { return m_primary_fd; }
+
+// The secondary file descriptor accessor.
+//
+// Returns the secondary file descriptor, or -1 if the secondary file descriptor
+// is not currently valid.
+int PseudoTerminal::GetSecondaryFileDescriptor() const {
+  return m_secondary_fd;
+}
+
+// Release ownership of the primary pseudo terminal file descriptor without
+// closing it. The destructor for this class will close the primary file
+// descriptor if the ownership isn't released using this call and the primary
+// file descriptor has been opened.
+int PseudoTerminal::ReleasePrimaryFileDescriptor() {
+  // Release ownership of the primary pseudo terminal file descriptor without
+  // closing it. (the destructor for this class will close it otherwise!)
+  int fd = m_primary_fd;
+  m_primary_fd = invalid_fd;
+  return fd;
+}
+
+// Release ownership of the secondary pseudo terminal file descriptor without
+// closing it. The destructor for this class will close the secondary file
+// descriptor if the ownership isn't released using this call and the secondary
+// file descriptor has been opened.
+int PseudoTerminal::ReleaseSecondaryFileDescriptor() {
+  // Release ownership of the secondary pseudo terminal file descriptor without
+  // closing it (the destructor for this class will close it otherwise!)
+  int fd = m_secondary_fd;
+  m_secondary_fd = invalid_fd;
+  return fd;
+}