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//===-- sanitizer_symbolizer_process_libcdep.cc ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implementation of SymbolizerProcess used by external symbolizers.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_platform.h"
#if SANITIZER_POSIX
#include "sanitizer_symbolizer_internal.h"
#include <errno.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#if SANITIZER_MAC
#include <util.h> // for forkpty()
#endif // SANITIZER_MAC
namespace __sanitizer {
SymbolizerProcess::SymbolizerProcess(const char *path, bool use_forkpty)
: path_(path),
input_fd_(kInvalidFd),
output_fd_(kInvalidFd),
times_restarted_(0),
failed_to_start_(false),
reported_invalid_path_(false),
use_forkpty_(use_forkpty) {
CHECK(path_);
CHECK_NE(path_[0], '\0');
}
const char *SymbolizerProcess::SendCommand(const char *command) {
for (; times_restarted_ < kMaxTimesRestarted; times_restarted_++) {
// Start or restart symbolizer if we failed to send command to it.
if (const char *res = SendCommandImpl(command))
return res;
Restart();
}
if (!failed_to_start_) {
Report("WARNING: Failed to use and restart external symbolizer!\n");
failed_to_start_ = true;
}
return 0;
}
bool SymbolizerProcess::Restart() {
if (input_fd_ != kInvalidFd)
internal_close(input_fd_);
if (output_fd_ != kInvalidFd)
internal_close(output_fd_);
return StartSymbolizerSubprocess();
}
const char *SymbolizerProcess::SendCommandImpl(const char *command) {
if (input_fd_ == kInvalidFd || output_fd_ == kInvalidFd)
return 0;
if (!WriteToSymbolizer(command, internal_strlen(command)))
return 0;
if (!ReadFromSymbolizer(buffer_, kBufferSize))
return 0;
return buffer_;
}
bool SymbolizerProcess::ReadFromSymbolizer(char *buffer, uptr max_length) {
if (max_length == 0)
return true;
uptr read_len = 0;
while (true) {
uptr just_read = internal_read(input_fd_, buffer + read_len,
max_length - read_len - 1);
// We can't read 0 bytes, as we don't expect external symbolizer to close
// its stdout.
if (just_read == 0 || just_read == (uptr)-1) {
Report("WARNING: Can't read from symbolizer at fd %d\n", input_fd_);
return false;
}
read_len += just_read;
if (ReachedEndOfOutput(buffer, read_len))
break;
}
buffer[read_len] = '\0';
return true;
}
bool SymbolizerProcess::WriteToSymbolizer(const char *buffer, uptr length) {
if (length == 0)
return true;
uptr write_len = internal_write(output_fd_, buffer, length);
if (write_len == 0 || write_len == (uptr)-1) {
Report("WARNING: Can't write to symbolizer at fd %d\n", output_fd_);
return false;
}
return true;
}
bool SymbolizerProcess::StartSymbolizerSubprocess() {
if (!FileExists(path_)) {
if (!reported_invalid_path_) {
Report("WARNING: invalid path to external symbolizer!\n");
reported_invalid_path_ = true;
}
return false;
}
int pid;
if (use_forkpty_) {
#if SANITIZER_MAC
fd_t fd = kInvalidFd;
// Use forkpty to disable buffering in the new terminal.
pid = forkpty(&fd, 0, 0, 0);
if (pid == -1) {
// forkpty() failed.
Report("WARNING: failed to fork external symbolizer (errno: %d)\n",
errno);
return false;
} else if (pid == 0) {
// Child subprocess.
ExecuteWithDefaultArgs(path_);
internal__exit(1);
}
// Continue execution in parent process.
input_fd_ = output_fd_ = fd;
// Disable echo in the new terminal, disable CR.
struct termios termflags;
tcgetattr(fd, &termflags);
termflags.c_oflag &= ~ONLCR;
termflags.c_lflag &= ~ECHO;
tcsetattr(fd, TCSANOW, &termflags);
#else // SANITIZER_MAC
UNIMPLEMENTED();
#endif // SANITIZER_MAC
} else {
int *infd = NULL;
int *outfd = NULL;
// The client program may close its stdin and/or stdout and/or stderr
// thus allowing socketpair to reuse file descriptors 0, 1 or 2.
// In this case the communication between the forked processes may be
// broken if either the parent or the child tries to close or duplicate
// these descriptors. The loop below produces two pairs of file
// descriptors, each greater than 2 (stderr).
int sock_pair[5][2];
for (int i = 0; i < 5; i++) {
if (pipe(sock_pair[i]) == -1) {
for (int j = 0; j < i; j++) {
internal_close(sock_pair[j][0]);
internal_close(sock_pair[j][1]);
}
Report("WARNING: Can't create a socket pair to start "
"external symbolizer (errno: %d)\n", errno);
return false;
} else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
if (infd == NULL) {
infd = sock_pair[i];
} else {
outfd = sock_pair[i];
for (int j = 0; j < i; j++) {
if (sock_pair[j] == infd) continue;
internal_close(sock_pair[j][0]);
internal_close(sock_pair[j][1]);
}
break;
}
}
}
CHECK(infd);
CHECK(outfd);
// Real fork() may call user callbacks registered with pthread_atfork().
pid = internal_fork();
if (pid == -1) {
// Fork() failed.
internal_close(infd[0]);
internal_close(infd[1]);
internal_close(outfd[0]);
internal_close(outfd[1]);
Report("WARNING: failed to fork external symbolizer "
" (errno: %d)\n", errno);
return false;
} else if (pid == 0) {
// Child subprocess.
internal_close(STDOUT_FILENO);
internal_close(STDIN_FILENO);
internal_dup2(outfd[0], STDIN_FILENO);
internal_dup2(infd[1], STDOUT_FILENO);
internal_close(outfd[0]);
internal_close(outfd[1]);
internal_close(infd[0]);
internal_close(infd[1]);
for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--)
internal_close(fd);
ExecuteWithDefaultArgs(path_);
internal__exit(1);
}
// Continue execution in parent process.
internal_close(outfd[0]);
internal_close(infd[1]);
input_fd_ = infd[0];
output_fd_ = outfd[1];
}
// Check that symbolizer subprocess started successfully.
int pid_status;
SleepForMillis(kSymbolizerStartupTimeMillis);
int exited_pid = waitpid(pid, &pid_status, WNOHANG);
if (exited_pid != 0) {
// Either waitpid failed, or child has already exited.
Report("WARNING: external symbolizer didn't start up correctly!\n");
return false;
}
return true;
}
} // namespace __sanitizer
#endif // SANITIZER_POSIX
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