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#include "processPipes.h"
#include <unistd.h>
#include <poll.h>
#include <cstring>
#include <sys/resource.h>
#include <stdexcept>
#include <sys.h>
#include "scopeExit.h"
// NOLINTNEXTLINE(modernize-concat-nested-namespaces)
namespace AdHoc {
namespace System {
using PipePair = std::array<int, 2>;
static
void
pipe(PipePair & pipes, ScopeExit & tidyUp)
{
if (::pipe(pipes.data())) {
throw SystemException("pipe(2) failed", strerror(errno), errno);
}
tidyUp.onFailure.emplace_back([pipes] {
close(pipes[0]);
close(pipes[1]);
});
}
ProcessPipes::ProcessPipes(const std::vector<std::string> & args, bool i, bool o, bool e) :
in(-1),
out(-1),
error(-1)
{
if (args.empty()) {
throw std::invalid_argument("args is empty");
}
PipePair ipipes { -1, -1 }, opipes { -1, -1 }, epipes { -1, -1 };
ScopeExit tidyUp;
if (i) {
pipe(ipipes, tidyUp);
}
if (o) {
pipe(opipes, tidyUp);
}
if (e) {
pipe(epipes, tidyUp);
}
switch (child = fork()) {
case -1: // fail
throw SystemException("fork(2) failed", strerror(errno), errno);
default: // parent
if (i) {
close(ipipes[0]);
in = ipipes[1];
}
if (o) {
close(opipes[1]);
out = opipes[0];
}
if (e) {
close(epipes[1]);
error = epipes[0];
}
break;
case 0: // in child
if (i) {
close(ipipes[1]);
dup2(ipipes[0], 0);
}
if (o) {
close(opipes[0]);
dup2(opipes[1], 1);
}
if (e) {
close(epipes[0]);
dup2(epipes[1], 2);
}
closeAllOpenFiles();
std::vector<char *> buf(args.size() + 1);
auto w = buf.begin();
for (const auto & p : args) {
*w++ = strdup(p.c_str());
}
*w = nullptr;
if (buf[0]) {
execv(buf[0], buf.data());
}
abort();
break;
}
}
ProcessPipes::~ProcessPipes()
{
if (in >= 0) {
close(in);
}
if (out >= 0) {
close(out);
}
if (error >= 0) {
close(error);
}
}
int
ProcessPipes::fdIn() const
{
return in;
}
int
ProcessPipes::fdOut() const
{
return out;
}
int
ProcessPipes::fdError() const
{
return error;
}
pid_t
ProcessPipes::pid() const
{
return child;
}
void
ProcessPipes::closeAllOpenFiles()
{
rlimit lim { };
getrlimit(RLIMIT_NOFILE, &lim);
std::vector<struct pollfd> fds;
fds.reserve(lim.rlim_max);
for (int n = 3; n < (int)lim.rlim_max; n += 1) {
fds.push_back({n, 0, 0});
}
poll(&fds.front(), fds.size(), 0);
for(const auto & pfd : fds) {
if (!(pfd.revents & POLLNVAL)) {
close(pfd.fd);
}
}
}
}
}
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