Add stderr support to pipe

Author: resetius

coroio/http/httpd.hpp

@@ -94,12 +94,12 @@ class TResponse {
 };
 
 struct IRouter {
-    virtual TFuture<void> HandleRequest(const TRequest& request, TResponse& response) = 0;
+    virtual TFuture<void> HandleRequest(TRequest& request, TResponse& response) = 0;
 };
 
 class THelloWorldRouter : public IRouter {
 public:
-    TFuture<void> HandleRequest(const TRequest& request, TResponse& response) override {
+    TFuture<void> HandleRequest(TRequest& request, TResponse& response) override {
         if (request.Uri().Path() == "/") {
             response.SetStatus(200);
             response.SetHeader("Content-Type", "text/plain");

coroio/pipe/pipe.cpp

@@ -17,7 +17,7 @@ namespace NNet {
 
 namespace {
 
-[[maybe_unused]] void SetCloseOnExec(int fd) {
+void SetCloseOnExec(int fd) {
     int flags = fcntl(fd, F_GETFD);
     if (flags == -1) {
         throw std::runtime_error("fcntl(F_GETFD) failed");
@@ -70,8 +70,18 @@ void TPipe::TPipeLow::Fork() {
         close(pipeStdin[1]);
         throw std::system_error(code, std::generic_category(), "pipe() failed for stdout");
     }
+    int pipeStderr[2];
+    if (pipe(pipeStderr) == -1) {
+        auto code = errno;
+        close(pipeStdin[0]);
+        close(pipeStdin[1]);
+        close(pipeStdout[0]);
+        close(pipeStdout[1]);
+        throw std::system_error(code, std::generic_category(), "pipe() failed for stderr");
+    }
     SetCloseOnExec(pipeStdin[0]); SetCloseOnExec(pipeStdin[1]);
     SetCloseOnExec(pipeStdout[0]); SetCloseOnExec(pipeStdout[1]);
+    SetCloseOnExec(pipeStderr[0]); SetCloseOnExec(pipeStderr[1]);
 
     auto pid = fork();
     if (pid == -1) {
@@ -80,13 +90,16 @@ void TPipe::TPipeLow::Fork() {
         close(pipeStdin[1]);
         close(pipeStdout[0]);
         close(pipeStdout[1]);
+        close(pipeStderr[0]);
+        close(pipeStderr[1]);
         throw std::system_error(code, std::generic_category(), "fork() failed");
     }
 
     if (pid == 0) {
         // Child process
         close(pipeStdin[1]);
         close(pipeStdout[0]);
+        close(pipeStderr[0]);
 
         if (dup2(pipeStdin[0], STDIN_FILENO) == -1) {
             std::cerr << "dup2() failed for stdin: " << strerror(errno) << std::endl;
@@ -96,9 +109,14 @@ void TPipe::TPipeLow::Fork() {
             std::cerr << "dup2() failed for stdout: " << strerror(errno) << std::endl;
             _exit(1);
         }
+        if (dup2(pipeStderr[1], STDERR_FILENO) == -1) {
+            std::cerr << "dup2() failed for stderr: " << strerror(errno) << std::endl;
+            _exit(1);
+        }
 
         close(pipeStdin[0]);
         close(pipeStdout[1]);
+        close(pipeStderr[1]);
 
         std::vector<char*> cargs;
         cargs.reserve(Args.size() + 2);
@@ -115,19 +133,26 @@ void TPipe::TPipeLow::Fork() {
         // Parent process
         close(pipeStdin[0]);
         close(pipeStdout[1]);
+        close(pipeStderr[1]);
 
         ChildPid = pid;
         WriteFd = pipeStdin[1];
         ReadFd = pipeStdout[0];
+        ErrFd = pipeStderr[0];
         SetNonBlocking(ReadFd);
         SetNonBlocking(WriteFd);
+        SetNonBlocking(ErrFd);
     }
 }
 
 TFuture<ssize_t> TPipe::ReadSome(void* buffer, size_t size) {
     co_return co_await ReadHandle->ReadSome(buffer, size);
 }
 
+TFuture<ssize_t> TPipe::ReadSomeErr(void* buffer, size_t size) {
+    co_return co_await ErrHandle->ReadSome(buffer, size);
+}
+
 TFuture<ssize_t> TPipe::WriteSome(const void* buffer, size_t size) {
     co_return co_await WriteHandle->WriteSome(buffer, size);
 }

coroio/pipe/pipe.hpp

@@ -16,9 +16,33 @@ class TPipe {
 
         ReadHandle = std::make_unique<TPipeFileHandle<TPoller>>(PipeLow.ReadFd, poller);
         WriteHandle = std::make_unique<TPipeFileHandle<TPoller>>(PipeLow.WriteFd, poller);
+        ErrHandle = std::make_unique<TPipeFileHandle<TPoller>>(PipeLow.ErrFd, poller);
+    }
+
+    void CloseRead() {
+        ReadHandle.reset();
+    }
+
+    void CloseWrite() {
+        WriteHandle.reset();
+    }
+
+    void CloseErr() {
+        ErrHandle.reset();
+    }
+
+    int Wait() {
+        int status;
+        waitpid(PipeLow.ChildPid, &status, 0);
+        if (WIFEXITED(status)) {
+            return WEXITSTATUS(status);
+        } else {
+            return -1;
+        }
     }
 
     TFuture<ssize_t> ReadSome(void* buffer, size_t size);
+    TFuture<ssize_t> ReadSomeErr(void* buffer, size_t size);
     TFuture<ssize_t> WriteSome(const void* buffer, size_t size);
 
 private:
@@ -33,6 +57,7 @@ class TPipe {
 
         int ReadFd = -1;
         int WriteFd = -1;
+        int ErrFd = -1;
         int ChildPid = -1;
     };
 
@@ -61,6 +86,7 @@ class TPipe {
     TPipeLow PipeLow;
     std::unique_ptr<TTypelessFileHandle> ReadHandle;
     std::unique_ptr<TTypelessFileHandle> WriteHandle;
+    std::unique_ptr<TTypelessFileHandle> ErrHandle;
 };
 
 #endif  // _WIN32

tests/test_pipe.cpp

@@ -55,6 +55,32 @@ void test_pipe_basic_read_write(void**) {
     assert_true(bytesRead == sizeof(testData));
     assert_true(memcmp(buffer, testData, sizeof(testData)) == 0);
 }
+
+void test_pipe_read_stderr(void**) {
+    TLoop<TDefaultPoller> loop;
+    auto& poller = loop.Poller();
+    std::string bashPath = "/bin/bash";
+    TPipe pipe(poller, bashPath, {"-c", "echo 'error message' 1>&2"});
+
+    char buffer[64] = {};
+    size_t bytesRead = sizeof(buffer);
+    auto reader = [](TPipe& pipe, char* buffer, size_t& size) -> TFuture<void> {
+        try {
+            size = co_await pipe.ReadSomeErr(buffer, size);
+        } catch (const std::exception& ex) {
+            std::cerr << "Read error: " << ex.what() << "\n";
+        }
+    }(pipe, buffer, bytesRead);
+
+    while (!reader.done()) {
+        loop.Step();
+    }
+
+    const char expected[] = "error message\n";
+    assert_true(bytesRead == sizeof(expected)-1);
+    assert_true(memcmp(buffer, expected, sizeof(expected)-1) == 0);
+}
+
 #endif // _WIN32
 
 int main(int argc, char** argv) {
@@ -68,6 +94,7 @@ int main(int argc, char** argv) {
 
 #ifndef _WIN32
     ADD_TEST(cmocka_unit_test, test_pipe_basic_read_write);
+    ADD_TEST(cmocka_unit_test, test_pipe_read_stderr);
 #endif
 
     return _cmocka_run_group_tests("test_pipe", tests.data(), tests.size(), NULL, NULL);