From: Daniel Karbach Date: Thu, 17 Nov 2016 15:51:27 +0000 (+0100) Subject: Process X-Git-Url: http://git.localhorst.tv/?p=blank.git;a=commitdiff_plain;h=8e75a34131e9fb04fb44a73f036da2aca872fa95 Process API for spawning and communicating with child processes totally untested on win32; I'd be surprised if it even compiles --- diff --git a/src/app/Process.hpp b/src/app/Process.hpp new file mode 100644 index 0000000..985b661 --- /dev/null +++ b/src/app/Process.hpp @@ -0,0 +1,50 @@ +#ifndef BLANK_APP_PROCESS_HPP_ +#define BLANK_APP_PROCESS_HPP_ + +#include +#include +#include + + +namespace blank { + +class Process { + +public: + /// launch process executing the file at given path with + /// given arguments and environment + Process( + const std::string &path, + const std::vector &args, + const std::vector &env); + ~Process(); + +public: + /// write to the process' input stream + /// data is taken from given buffer, at most max_len bytes + /// @return the number of bytes written + std::size_t WriteIn(const void *buffer, std::size_t max_len); + /// read from the process' output stream + /// data is stored in the given buffer, at most max_len bytes + /// @return the number of bytes read + std::size_t ReadOut(void *buffer, std::size_t max_len); + /// read from the process' error stream + /// data is stored in the given buffer, at most max_len bytes + /// @return the number of bytes read + std::size_t ReadErr(void *buffer, std::size_t max_len); + + /// wait until the process exits and fetch its exit status + int Join(); + +private: + struct Impl; + std::unique_ptr impl; + + bool joined; + int status; + +}; + +} + +#endif 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 +# include +# include +# include +#endif + +#include + +using namespace std; + + +namespace blank { + +struct Process::Impl { + + Impl( + const string &path_in, + const vector &args, + const vector &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 &args, + const vector &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 &args, + const vector &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(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(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 +} + +} diff --git a/tst/app/ProcessTest.cpp b/tst/app/ProcessTest.cpp new file mode 100644 index 0000000..778b7f6 --- /dev/null +++ b/tst/app/ProcessTest.cpp @@ -0,0 +1,118 @@ +#include "ProcessTest.hpp" + +#include "app/Process.hpp" + +CPPUNIT_TEST_SUITE_REGISTRATION(blank::test::ProcessTest); + +using namespace std; + + +namespace blank { +namespace test { + +void ProcessTest::setUp() { + +} + +void ProcessTest::tearDown() { + +} + + +void ProcessTest::testExit() { +#ifdef __WIN32 +# error "TODO: implemente Process tests for windows" +#else + + { + Process proc("/usr/bin/env", { "env", "true" }, { }); + int status = proc.Join(); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "exit status of true assumed 0", + 0, status); + } + + { + Process proc("/usr/bin/env", { "env", "false" }, { }); + int status = proc.Join(); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "exit status of false assumed 1", + 1, status); + } + +#endif +} + +void ProcessTest::testStream() { +#ifdef __WIN32 +# error "TODO: implemente Process tests for windows" +#else + + { + const string test_input("hello, world"); + const string expected_output("hello, world\n"); + Process proc("/usr/bin/env", { "env", "echo", test_input.c_str() }, { }); + char buffer[expected_output.length() + 1]; + size_t len = proc.ReadOut(buffer, sizeof(buffer)); + const string output(buffer, len); + int status = proc.Join(); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "exit status of echo assumed 0", + 0, status); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected length of echo output", + expected_output.size(), len); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected output of echo", + expected_output, output); + } + + { + const string test_input("hello, error"); + const string expected_output("hello, error\n"); + Process proc("/usr/bin/env", { "env", "sh", "-c", "echo $1 >&2", "echo", test_input.c_str() }, { }); + char buffer[expected_output.length() + 1]; + size_t len = proc.ReadErr(buffer, sizeof(buffer)); + const string output(buffer, len); + int status = proc.Join(); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "exit status of echo assumed 0", + 0, status); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected length of echo output", + expected_output.size(), len); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected error output of echo", + expected_output, output); + } + + + { + const string test_input("dog"); + const string expected_output("dog"); + Process proc("/usr/bin/env", { "env", "cat" }, { }); + size_t len = proc.WriteIn(test_input.c_str(), test_input.size()); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected length of input to cat", + test_input.size(), len); + + char buffer[expected_output.length() + 1]; + len = proc.ReadOut(buffer, sizeof(buffer)); + const string output(buffer, len); + int status = proc.Join(); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "exit status of cat assumed 0", + 0, status); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected length of cat output", + expected_output.size(), len); + CPPUNIT_ASSERT_EQUAL_MESSAGE( + "unexpected output of cat", + expected_output, output); + } + +#endif +} + +} +} diff --git a/tst/app/ProcessTest.hpp b/tst/app/ProcessTest.hpp new file mode 100644 index 0000000..972fbe5 --- /dev/null +++ b/tst/app/ProcessTest.hpp @@ -0,0 +1,32 @@ +#ifndef BLANK_TEST_APP_PROCESSTEST_HPP_ +#define BLANK_TEST_APP_PROCESSTEST_HPP_ + +#include + + +namespace blank { +namespace test { + +class ProcessTest +: public CppUnit::TestFixture { + +CPPUNIT_TEST_SUITE(ProcessTest); + +CPPUNIT_TEST(testExit); +CPPUNIT_TEST(testStream); + +CPPUNIT_TEST_SUITE_END(); + +public: + void setUp(); + void tearDown(); + + void testExit(); + void testStream(); + +}; + +} +} + +#endif