X-Git-Url: https://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fapp%2Fproc.cpp;fp=src%2Fapp%2Fproc.cpp;h=8809856c2a8c3640f45c23e3737e3a79702b0d5e;hb=8e75a34131e9fb04fb44a73f036da2aca872fa95;hp=0000000000000000000000000000000000000000;hpb=cdcfdb33e9b625976909a9fb604b756a1a057788;p=blank.git

diff --git a/src/app/proc.cpp b/src/app/proc.cpp
new file mode 100644
index 0000000..8809856
--- /dev/null
+++ b/src/app/proc.cpp
@@ -0,0 +1,302 @@
+#include "Process.hpp"
+
+#ifdef __WIN32
+#  error "TODO: windows implementation of Process"
+#else
+#  include <cstdio>
+#  include <fcntl.h>
+#  include <unistd.h>
+#  include <sys/wait.h>
+#endif
+
+#include <stdexcept>
+
+using namespace std;
+
+
+namespace blank {
+
+struct Process::Impl {
+
+	Impl(
+		const string &path_in,
+		const vector<string> &args,
+		const vector<string> &env);
+	~Impl();
+
+	size_t WriteIn(const void *buffer, size_t max_len);
+	size_t ReadOut(void *buffer, size_t max_len);
+	size_t ReadErr(void *buffer, size_t max_len);
+
+	int Join();
+
+#ifdef __WIN32
+	PROCESS_INFORMATION pi;
+	HANDLE fd_in[2];
+	HANDLE fd_out[2];
+	HANDLE fd_err[2];
+#else
+	int pid;
+	int fd_in[2];
+	int fd_out[2];
+	int fd_err[2];
+#endif
+
+};
+
+
+Process::Process(
+	const string &path,
+	const vector<string> &args,
+	const vector<string> &env)
+: impl(new Impl(path, args, env))
+, joined(false)
+, status(0) {
+
+}
+
+Process::~Process() {
+	Join();
+}
+
+
+size_t Process::WriteIn(const void *buffer, size_t max_len) {
+	return impl->WriteIn(buffer, max_len);
+}
+
+size_t Process::ReadOut(void *buffer, size_t max_len) {
+	return impl->ReadOut(buffer, max_len);
+}
+
+size_t Process::ReadErr(void *buffer, size_t max_len) {
+	return impl->ReadErr(buffer, max_len);
+}
+
+int Process::Join() {
+	if (joined) {
+		return status;
+	} else {
+		status = impl->Join();
+		joined = true;
+		return status;
+	}
+}
+
+
+Process::Impl::Impl(
+	const string &path_in,
+	const vector<string> &args,
+	const vector<string> &env
+) {
+	const char *path = path_in.c_str();
+	char *envp[env.size() + 1];
+	for (size_t i = 0; i < env.size(); ++i) {
+		envp[i] = const_cast<char *>(env[i].c_str());
+	}
+	envp[env.size()] = nullptr;
+#ifdef __WIN32
+	string cmdline;
+	for (const auto &arg : args) {
+		cmdline += '"';
+		cmdline += arg;
+		cmdline += '"';
+	}
+
+	SECURITY_ATTRIBUTES sa;
+	sa.nLength = sizeof(SECURITY_ATTRIBUTES);
+	sa.bInheritHandle = true;
+	sa.lpSecurityDescriptor = nullptr;
+	if (!CreatePipe(&fd_in[0], &fd_in[1], &sa, 0)) {
+		throw runtime_error("failed to open pipe for child process' stdin");
+	}
+	if (!SetHandleInformation(fd_in[1], HANDLE_FLAG_INHERIT, 0)) {
+		throw runtime_error("failed to stop child process from inheriting stdin write handle");
+	}
+	if (!CreatePipe(&fd_out[0], &fd_out[1], &sa, 0)) {
+		throw runtime_error("failed to open pipe for child process' stdout");
+	}
+	if (!SetHandleInformation(fd_out[0], HANDLE_FLAG_INHERIT, 0)) {
+		throw runtime_error("failed to stop child process from inheriting stdout read handle");
+	}
+	if (!CreatePipe(&fd_err[0], &fd_err[1], &sa, 0)) {
+		throw runtime_error("failed to open pipe for child process' stderr");
+	}
+	if (!SetHandleInformation(fd_err[0], HANDLE_FLAG_INHERIT, 0)) {
+		throw runtime_error("failed to stop child process from inheriting stderr read handle");
+	}
+
+	STARTUPINFO si;
+	ZeroMemory(&si, sizeof(STARTUPINFO));
+	si.cb = sizeof(STARTUPINFO);
+	si.hStdError = fd_err[1];
+	si.hStdOutput = fd_out[1];
+	si.hStdInput = fd_in[0];
+	si.dwFlags |= STARTF_USESTDHANDLES;
+	ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
+
+	if (!CreateProcess(
+		path,
+		cmdline.c_str(),
+		nullptr,
+		nullptr,
+		true,
+		0,
+		envp,
+		nullptr,
+		&si,
+		&pi
+	)) {
+		throw runtime_error("CreateProcess");
+	}
+#else
+	char *argv[args.size() + 1];
+	for (size_t i = 0; i < args.size(); ++i) {
+		// I was promised exec won't modify my characters
+		argv[i] = const_cast<char *>(args[i].c_str());
+	}
+	argv[args.size()] = nullptr;
+
+	if (pipe(fd_in) != 0) {
+		throw runtime_error("failed to open pipe for child process' stdin");
+	}
+	if (pipe(fd_out) != 0) {
+		throw runtime_error("failed to open pipe for child process' stdout");
+	}
+	if (pipe(fd_err) != 0) {
+		throw runtime_error("failed to open pipe for child process' stderr");
+	}
+
+	pid = fork();
+	if (pid == -1) {
+		throw runtime_error("fork");
+	} else if (pid == 0) {
+
+		if (dup2(fd_in[0], STDIN_FILENO) == -1) {
+			exit(EXIT_FAILURE);
+		}
+		if (dup2(fd_out[1], STDOUT_FILENO) == -1) {
+			exit(EXIT_FAILURE);
+		}
+		if (dup2(fd_err[1], STDERR_FILENO) == -1) {
+			exit(EXIT_FAILURE);
+		}
+
+		close(fd_in[0]);
+		close(fd_in[1]);
+		close(fd_out[0]);
+		close(fd_out[1]);
+		close(fd_err[0]);
+		close(fd_err[1]);
+
+		execve(path, argv, envp);
+		// if execve returns, something bad happened
+		exit(EXIT_FAILURE);
+
+	} else {
+
+		close(fd_in[0]);
+		close(fd_out[1]);
+		close(fd_err[1]);
+
+	}
+}
+#endif
+
+Process::Impl::~Impl() {
+
+}
+
+size_t Process::Impl::WriteIn(const void *buffer, size_t max_len) {
+#ifdef __WIN32
+	DWORD written;
+	if (!WriteFile(fd_in[1], buffer, max_len, &written, nullptr)) {
+		throw runtime_error("failed to write to child process' input stream");
+	}
+	return written;
+#else
+	int written = write(fd_in[1], buffer, max_len);
+	if (written < 0) {
+		if (errno == EAGAIN) {
+			return 0;
+		} else {
+			throw runtime_error("failed to write to child process' input stream");
+		}
+	}
+	return written;
+#endif
+}
+
+size_t Process::Impl::ReadOut(void *buffer, size_t max_len) {
+#ifdef __WIN32
+	DWORD ret;
+	if (!ReadFile(fd_out[0], buffer, max_len, &ret, nullptr)) {
+		throw runtime_error("failed to read from child process' output stream");
+	}
+	return ret;
+#else
+	int ret = read(fd_out[0], buffer, max_len);
+	if (ret < 0) {
+		if (errno == EAGAIN) {
+			return 0;
+		} else {
+			throw runtime_error("failed to read from child process' output stream");
+		}
+	}
+	return ret;
+#endif
+}
+
+size_t Process::Impl::ReadErr(void *buffer, size_t max_len) {
+#ifdef __WIN32
+	DWORD ret;
+	if (!ReadFile(fd_err[0], buffer, max_len, &ret, nullptr)) {
+		throw runtime_error("failed to read from child process' error stream");
+	}
+	return ret;
+#else
+	int ret = read(fd_err[0], buffer, max_len);
+	if (ret < 0) {
+		if (errno == EAGAIN) {
+			return 0;
+		} else {
+			throw runtime_error("failed to read from child process' error stream");
+		}
+	}
+	return ret;
+#endif
+}
+
+int Process::Impl::Join() {
+#ifdef __WIN32
+	CloseHandle(fd_in[1]);
+	CloseHandle(fd_out[0]);
+	CloseHandle(fd_err[0]);
+
+	DWORD exit_code;
+	WaitForSingleObject(pi.hProcess, INFINITE);
+	GetExitCodeProcess(pi.hProcess, &exit_code);
+	CloseHandle(pi.hProcess);
+	CloseHandle(pi.hThread);
+	return exit_code;
+#else
+	// close streams before waiting on child termination
+	close(fd_in[1]);
+	close(fd_out[0]);
+	close(fd_err[0]);
+
+	while (true) {
+		int status;
+		int result = waitpid(pid, &status, 0);
+		if (result == -1) {
+			throw runtime_error("error waiting on child process");
+		}
+		if (result == pid && WIFEXITED(status)) {
+			return WEXITSTATUS(status);
+		}
+		// otherwise, child probably signalled, which we don't care
+		// about (please don't tell youth welfare), so try again
+	}
+#endif
+}
+
+}