-
Notifications
You must be signed in to change notification settings - Fork 0
/
ptpipe.cc
235 lines (198 loc) · 5.81 KB
/
ptpipe.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <termios.h>
#include <unistd.h>
#include <condition_variable>
#include <iostream>
#include <mutex>
#include <thread>
#include <vector>
// #include <boost/process.hpp>
// namespace bp = boost::process;
static const size_t kDefaultBufSize = 4096;
// Adjust termios flags (e.g. clear ICANON for no input buffering)
// Constructor sets flags, and destructor restores, once object goes out of
// scope
class TermAttr {
public:
// Constructor saves existing termios flags, and sets/clears flags
TermAttr(int fd, unsigned clear_flags = 0, unsigned set_flags = 0) : fd_{fd} {
tcgetattr(fd, &old_term_);
new_term_ = old_term_;
new_term_.c_lflag &= ~clear_flags;
new_term_.c_lflag |= set_flags;
::tcsetattr(fd, TCSANOW, &new_term_);
};
// Copy doesn't make sense as a unique object is required to track the given
// terminal resource
TermAttr(const TermAttr &) = delete;
TermAttr &operator=(const TermAttr &) = delete;
// Move is possibly useful
TermAttr(TermAttr &&) = default;
TermAttr &operator=(TermAttr &&) = default;
// Destructor restores saved termios flags
~TermAttr() { ::tcsetattr(fd_, TCSANOW, &old_term_); };
private:
struct termios old_term_;
struct termios new_term_;
int fd_;
};
namespace {
// Spawn a thread to copy data from one FD to another
class Splicer {
public:
Splicer(int in_fd, int out_fd, std::string name = "",
size_t buf_size = kDefaultBufSize)
: in_fd_(in_fd),
out_fd_(out_fd),
name_(name),
buf_size_(buf_size),
sp_thread_(std::thread([this] { FdSplice(); })),
has_pipe_(IsPipe(in_fd_) || IsPipe(out_fd_)) {}
~Splicer() { sp_thread_.detach(); }
static void AllWait();
private:
Splicer() = delete;
Splicer(const Splicer &) = delete;
Splicer &operator=(const Splicer &) = delete;
Splicer(Splicer &&) = delete;
Splicer &operator=(Splicer &&) = delete;
static std::mutex done_mutex_;
static std::condition_variable done_condvar_;
static bool all_done_;
int in_fd_;
int out_fd_;
std::string name_;
size_t buf_size_;
std::thread sp_thread_;
const bool has_pipe_;
void FdSplice();
static bool IsPipe(int fd);
};
std::mutex Splicer::done_mutex_{};
std::condition_variable Splicer::done_condvar_{};
bool Splicer::all_done_{false};
void Splicer::AllWait() {
std::unique_lock<std::mutex> lk(done_mutex_);
done_condvar_.wait(lk, [] { return all_done_; });
}
void Splicer::FdSplice() {
#ifdef SPLICE_F_MOVE
if (has_pipe_) {
ssize_t splice_size;
while ((splice_size = ::splice(in_fd_, NULL, out_fd_, NULL, buf_size_,
SPLICE_F_MOVE | SPLICE_F_MORE)) >= 0) {
}
if (splice_size == -1) {
std::cerr << name_ << " splice(" << in_fd_ << ", " << out_fd_
<< ") error: " << errno << std::endl;
}
} else {
#endif
ssize_t read_size;
std::vector<uint8_t> buf(buf_size_);
while ((read_size = ::read(in_fd_, buf.data(), buf_size_)) > 0) {
ssize_t write_size = ::write(out_fd_, buf.data(), read_size);
if (write_size == -1) {
std::cerr << name_ << " write(" << out_fd_ << ") error: " << errno
<< std::endl;
break;
}
};
if (read_size == -1) {
std::cerr << name_ << " read(" << in_fd_ << ") error: " << errno
<< std::endl;
}
#ifdef SPLICE_F_MOVE
}
#endif
{
std::lock_guard<std::mutex> lk(done_mutex_);
all_done_ = true;
}
done_condvar_.notify_one();
}
bool Splicer::IsPipe(int fd) {
struct stat stat_buf;
return ::fstat(fd, &stat_buf) && S_ISFIFO(stat_buf.st_mode);
}
int Child(int pt_fd, int err_fd, int argc, char *const *argv) {
std::string child_dev(::ptsname(pt_fd) ?: "");
::close(pt_fd);
::setsid();
int child_fd = ::open(child_dev.c_str(), O_RDWR | O_NOCTTY);
if (child_fd < 0) {
return -1;
}
if (::ioctl(child_fd, TIOCSCTTY, nullptr) == -1) {
std::cerr << "ioctl(TIOCSCTTY) error: " << errno << std::endl;
return -1;
}
::dup2(child_fd, STDIN_FILENO);
::dup2(child_fd, STDOUT_FILENO);
::dup2(err_fd, STDERR_FILENO);
::close(child_fd);
::close(err_fd);
if (::execvp(argv[1], &argv[1]) == -1) {
std::cerr << "execvp() error: " << errno << std::endl;
return -1;
}
return 0;
}
void Parent(int pt_fd, int err_fd) {
TermAttr ta{STDIN_FILENO, ICANON};
Splicer up{STDIN_FILENO, pt_fd, "up"};
Splicer down{pt_fd, STDOUT_FILENO, "down"};
Splicer down_err{err_fd, STDERR_FILENO, "down err"};
Splicer::AllWait();
}
} // namespace
int main(int argc, char *const *argv) {
std::cout << "argc=" << argc << std::endl;
for (int i = 0; i < argc; ++i) {
std::cout << "argv[" << i << "]=\"" << argv[i] << "\"" << std::endl;
}
int pt_fd = ::posix_openpt(O_RDWR | O_NOCTTY);
if (pt_fd == -1 || ::grantpt(pt_fd) == -1 || ::unlockpt(pt_fd) == -1) {
return -1;
}
std::cout << "child device is: " << (::ptsname(pt_fd) ?: "") << std::endl;
int err_fd[2];
if (::pipe(err_fd) == -1) {
std::cerr << "pipe() error: " << errno << std::endl;
return -1;
}
int ret;
pid_t pid = ::fork();
switch (pid) {
case -1:
std::cerr << "fork() error: " << errno << std::endl;
return -1;
case 0:
/* Child process */
ret = Child(pt_fd, err_fd[1], argc, argv);
if (-1 == ret) {
return ret;
}
break;
default:
/* Parent process */
std::cout << "Child pid " << pid << std::endl;
Parent(pt_fd, err_fd[0]);
}
int status = 0;
::waitpid(pid, &status, 0);
::close(pt_fd);
if (WIFEXITED(status)) {
return WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
return 128 + (WTERMSIG(status));
} else if (WIFSTOPPED(status)) {
return 128 + (WSTOPSIG(status));
} else {
return 1;
}
}