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#include "subprocess.h"
#include <map>
#include <errno.h>
#include <poll.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
Subprocess::Stream::Stream() : fd_(-1) {}
Subprocess::Stream::~Stream() {
if (fd_ >= 0)
close(fd_);
}
Subprocess::Subprocess() : pid_(-1) {}
Subprocess::~Subprocess() {
}
bool Subprocess::Start(const string& command, string* err) {
int stdout_pipe[2];
if (pipe(stdout_pipe) < 0) {
*err = strerror(errno);
return false;
}
stdout_.fd_ = stdout_pipe[0];
int stderr_pipe[2];
if (pipe(stderr_pipe) < 0) {
*err = strerror(errno);
return false;
}
stderr_.fd_ = stderr_pipe[0];
pid_ = fork();
if (pid_ < 0) {
*err = strerror(errno);
return false;
} else if (pid_ == 0) {
if (close(0) < 0 ||
dup2(stdout_pipe[1], 1) < 0 ||
dup2(stderr_pipe[1], 2) < 0 ||
close(stdout_pipe[0]) < 0 ||
close(stdout_pipe[1]) < 0 ||
close(stderr_pipe[0]) < 0 ||
// Leave stderr_pipe[1] alone so we can write to it on error.
execl("/bin/sh", "/bin/sh", "-c", command.c_str(), NULL) < 0) {
char* err = strerror(errno);
write(stderr_pipe[1], err, strlen(err));
}
_exit(1);
}
close(stdout_pipe[1]);
close(stderr_pipe[1]);
return true;
}
void Subprocess::OnFDReady(int fd) {
char buf[4 << 10];
ssize_t len = read(fd, buf, sizeof(buf));
Stream* stream = fd == stdout_.fd_ ? &stdout_ : &stderr_;
if (len > 0) {
stream->buf_.append(buf, len);
} else {
close(stream->fd_);
stream->fd_ = -1;
}
}
bool Subprocess::Finish(string* err) {
int status;
if (waitpid(pid_, &status, 0) < 0) {
*err = strerror(errno);
return false;
}
if (WIFEXITED(status)) {
int exit = WEXITSTATUS(status);
if (exit == 0)
return true;
*err = "nonzero exit status";
} else {
*err = "XXX something else went wrong";
}
return false;
}
void SubprocessSet::Add(Subprocess* subprocess) {
running_.push_back(subprocess);
}
void SubprocessSet::DoWork(string* err) {
struct pollfd* fds = new pollfd[running_.size() * 2];
map<int, Subprocess*> fd_to_subprocess;
int fds_count = 0;
for (vector<Subprocess*>::iterator i = running_.begin();
i != running_.end(); ++i) {
int fd = (*i)->stdout_.fd_;
if (fd >= 0) {
fd_to_subprocess[fd] = *i;
fds[fds_count].fd = fd;
fds[fds_count].events = POLLIN;
fds[fds_count].revents = 0;
++fds_count;
}
fd = (*i)->stderr_.fd_;
if (fd >= 0) {
fd_to_subprocess[fd] = *i;
fds[fds_count].fd = fd;
fds[fds_count].events = POLLIN;
fds[fds_count].revents = 0;
++fds_count;
}
}
int ret = poll(fds, fds_count, -1);
if (ret == -1) {
if (errno != EINTR)
perror("poll");
return;
}
for (int i = 0; i < fds_count; ++i) {
if (fds[i].revents) {
Subprocess* subproc = fd_to_subprocess[fds[i].fd];
if (fds[i].revents) {
subproc->OnFDReady(fds[i].fd);
if (subproc->done()) {
subproc->Finish(err);
finished_.push(subproc);
}
}
}
}
}
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