v29.4-roots.2 · Commit 2: [PATCH 02/21] runtime: preserve shared operator controls

src/util/subprocess.h

Before: src/util/subprocess.h · After: src/util/subprocess.h

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index 3449fa3b1bacce60422267110b27e54b13b19458..7cabd1baf27c5366aea0fed3a6b6bbb4ded01475 100644

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src/util/subprocess.h CHANGED Viewed

@@ -36,6 +36,8 @@ Documentation for C++ subprocessing library.
 #ifndef BITCOIN_UTIL_SUBPROCESS_H
 #define BITCOIN_UTIL_SUBPROCESS_H
+#include <util/fs.h>
+#include <util/strencodings.h>
 #include <util/syserror.h>
 #include <algorithm>
@@ -65,13 +67,9 @@ Documentation for C++ subprocessing library.
 extern "C" {
 #ifdef __USING_WINDOWS__
-  #include <Windows.h>
+  #include <windows.h>
   #include <io.h>
   #include <cwchar>
-  #define close _close
-  #define open _open
-  #define fileno _fileno
 #else
   #include <sys/wait.h>
   #include <unistd.h>
@@ -81,6 +79,22 @@ extern "C" {
   #include <sys/types.h>
 }
+// The Microsoft C++ compiler issues deprecation warnings
+// for the standard POSIX function names.
+// Its preferred implementations have a leading underscore.
+// See: https://learn.microsoft.com/en-us/cpp/c-runtime-library/compatibility.
+#if (defined _MSC_VER)
+  #define subprocess_close _close
+  #define subprocess_fileno _fileno
+  #define subprocess_open _open
+  #define subprocess_write _write
+#else
+  #define subprocess_close close
+  #define subprocess_fileno fileno
+  #define subprocess_open open
+  #define subprocess_write write
+#endif
 /*!
  * Getting started with reading this source code.
  * The source is mainly divided into four parts:
@@ -159,6 +173,7 @@ public:
 //--------------------------------------------------------------------
 namespace util
 {
+#ifdef __USING_WINDOWS__
   inline void quote_argument(const std::wstring &argument, std::wstring &command_line,
                       bool force)
   {
@@ -169,7 +184,7 @@ namespace util
     //
     if (force == false && argument.empty() == false &&
-        argument.find_first_of(L" \t\n\v\"") == argument.npos) {
+        argument.find_first_of(L" \t\n\v") == argument.npos) {
       command_line.append(argument);
     }
     else {
@@ -219,7 +234,6 @@ namespace util
     }
   }
-#ifdef __USING_WINDOWS__
   inline std::string get_last_error(DWORD errorMessageID)
   {
     if (errorMessageID == 0)
@@ -264,7 +278,7 @@ namespace util
     FILE *fp = _fdopen(os_fhandle, mode);
     if (fp == 0) {
-      _close(os_fhandle);
+      subprocess_close(os_fhandle);
       throw OSError("_fdopen", 0);
     }
@@ -334,10 +348,14 @@ namespace util
   void set_clo_on_exec(int fd, bool set = true)
   {
     int flags = fcntl(fd, F_GETFD, 0);
+    if (flags == -1) {
+        throw OSError("fcntl F_GETFD failed", errno);
+    }
     if (set) flags |= FD_CLOEXEC;
     else flags &= ~FD_CLOEXEC;
-    //TODO: should check for errors
-    fcntl(fd, F_SETFD, flags);
+    if (fcntl(fd, F_SETFD, flags) == -1) {
+        throw OSError("fcntl F_SETFD failed", errno);
+    }
   }
@@ -383,7 +401,7 @@ namespace util
   {
     size_t nwritten = 0;
     while (nwritten < length) {
-      int written = write(fd, buf + nwritten, length - nwritten);
+      int written = subprocess_write(fd, buf + nwritten, length - nwritten);
       if (written == -1) return -1;
       nwritten += written;
     }
@@ -411,7 +429,7 @@ namespace util
 #ifdef __USING_WINDOWS__
     return (int)fread(buf, 1, read_upto, fp);
 #else
-    int fd = fileno(fp);
+    int fd = subprocess_fileno(fp);
     int rbytes = 0;
     int eintr_cnter = 0;
@@ -520,6 +538,20 @@ namespace util
  * -------------------------------
  */
+/*!
+ * Option to close all file descriptors
+ * when the child process is spawned.
+ * The close fd list does not include
+ * input/output/error if they are explicitly
+ * set as part of the Popen arguments.
+ *
+ * Default value is false.
+ */
+struct close_fds {
+  explicit close_fds(bool c): close_all(c) {}
+  bool close_all = false;
+};
 /*!
  * Base class for all arguments involving string value.
  */
@@ -527,7 +559,7 @@ struct string_arg
 {
   string_arg(const char* arg): arg_value(arg) {}
   string_arg(std::string&& arg): arg_value(std::move(arg)) {}
-  string_arg(std::string arg): arg_value(std::move(arg)) {}
+  string_arg(const std::string& arg): arg_value(arg) {}
   std::string arg_value;
 };
@@ -573,10 +605,10 @@ struct input
   explicit input(int fd): rd_ch_(fd) {}
   // FILE pointer.
-  explicit input (FILE* fp):input(fileno(fp)) { assert(fp); }
+  explicit input (FILE* fp):input(subprocess_fileno(fp)) { assert(fp); }
   explicit input(const char* filename) {
-    int fd = open(filename, O_RDONLY);
+    int fd = subprocess_open(filename, O_RDONLY);
     if (fd == -1) throw OSError("File not found: ", errno);
     rd_ch_ = fd;
   }
@@ -606,10 +638,10 @@ struct output
 {
   explicit output(int fd): wr_ch_(fd) {}
-  explicit output (FILE* fp):output(fileno(fp)) { assert(fp); }
+  explicit output (FILE* fp):output(subprocess_fileno(fp)) { assert(fp); }
   explicit output(const char* filename) {
-    int fd = open(filename, O_APPEND | O_CREAT | O_RDWR, 0640);
+    int fd = subprocess_open(filename, O_APPEND | O_CREAT | O_RDWR, 0640);
     if (fd == -1) throw OSError("File not found: ", errno);
     wr_ch_ = fd;
   }
@@ -637,10 +669,10 @@ struct error
 {
   explicit error(int fd): wr_ch_(fd) {}
-  explicit error(FILE* fp):error(fileno(fp)) { assert(fp); }
+  explicit error(FILE* fp):error(subprocess_fileno(fp)) { assert(fp); }
   explicit error(const char* filename) {
-    int fd = open(filename, O_APPEND | O_CREAT | O_RDWR, 0640);
+    int fd = subprocess_open(filename, O_APPEND | O_CREAT | O_RDWR, 0640);
     if (fd == -1) throw OSError("File not found: ", errno);
     wr_ch_ = fd;
   }
@@ -717,6 +749,7 @@ struct ArgumentDeducer
   void set_option(input&& inp);
   void set_option(output&& out);
   void set_option(error&& err);
+  void set_option(close_fds&& cfds);
 private:
   Popen* popen_ = nullptr;
@@ -758,7 +791,10 @@ class Communication
 public:
   Communication(Streams* stream): stream_(stream)
   {}
-  void operator=(const Communication&) = delete;
+  Communication(const Communication&) = delete;
+  Communication& operator=(const Communication&) = delete;
+  Communication(Communication&&) = default;
+  Communication& operator=(Communication&&) = default;
 public:
   int send(const char* msg, size_t length);
   int send(const std::vector<char>& msg);
@@ -795,7 +831,10 @@ class Streams
 {
 public:
   Streams():comm_(this) {}
-  void operator=(const Streams&) = delete;
+  Streams(const Streams&) = delete;
+  Streams& operator=(const Streams&) = delete;
+  Streams(Streams&&) = default;
+  Streams& operator=(Streams&&) = default;
 public:
   void setup_comm_channels();
@@ -803,28 +842,28 @@ public:
   void cleanup_fds()
   {
     if (write_to_child_ != -1 && read_from_parent_ != -1) {
-      close(write_to_child_);
+      subprocess_close(write_to_child_);
     }
     if (write_to_parent_ != -1 && read_from_child_ != -1) {
-      close(read_from_child_);
+      subprocess_close(read_from_child_);
     }
     if (err_write_ != -1 && err_read_ != -1) {
-      close(err_read_);
+      subprocess_close(err_read_);
     }
   }
   void close_parent_fds()
   {
-    if (write_to_child_ != -1)  close(write_to_child_);
-    if (read_from_child_ != -1) close(read_from_child_);
-    if (err_read_ != -1)        close(err_read_);
+    if (write_to_child_ != -1)  subprocess_close(write_to_child_);
+    if (read_from_child_ != -1) subprocess_close(read_from_child_);
+    if (err_read_ != -1)        subprocess_close(err_read_);
   }
   void close_child_fds()
   {
-    if (write_to_parent_ != -1)  close(write_to_parent_);
-    if (read_from_parent_ != -1) close(read_from_parent_);
-    if (err_write_ != -1)        close(err_write_);
+    if (write_to_parent_ != -1)  subprocess_close(write_to_parent_);
+    if (read_from_parent_ != -1) subprocess_close(read_from_parent_);
+    if (err_write_ != -1)        subprocess_close(err_write_);
   }
   FILE* input()  { return input_.get(); }
@@ -902,6 +941,8 @@ private:
  *    Command provided in a single string.
  * wait()             - Wait for the child to exit.
  * retcode()          - The return code of the exited child.
+ * poll()             - Check the status of the running child.
+ * kill(sig_num)      - Kill the child. SIGTERM used by default.
  * send(...)          - Send input to the input channel of the child.
  * communicate(...)   - Get the output/error from the child and close the channels
  *                      from the parent side.
@@ -952,6 +993,12 @@ public:
   int wait() noexcept(false);
+  int poll() noexcept(false);
+  // Does not fail, Caller is expected to recheck the
+  // status with a call to poll()
+  void kill(int sig_num = 9);
   void set_out_buf_cap(size_t cap) { stream_.set_out_buf_cap(cap); }
   void set_err_buf_cap(size_t cap) { stream_.set_err_buf_cap(cap); }
@@ -1004,6 +1051,8 @@ private:
   std::future<void> cleanup_future_;
 #endif
+  bool close_fds_ = false;
   std::string exe_name_;
   // Command in string format
@@ -1012,6 +1061,7 @@ private:
   std::vector<std::string> vargs_;
   std::vector<char*> cargv_;
+  bool child_created_ = false;
   // Pid of the child process
   int child_pid_ = -1;
@@ -1043,7 +1093,19 @@ inline int Popen::wait() noexcept(false)
 #ifdef __USING_WINDOWS__
   int ret = WaitForSingleObject(process_handle_, INFINITE);
-  return 0;
+  // WaitForSingleObject with INFINITE should only return when process has signaled
+  if (ret != WAIT_OBJECT_0) {
+    throw OSError("Unexpected return code from WaitForSingleObject", 0);
+  }
+  DWORD dretcode_;
+  if (FALSE == GetExitCodeProcess(process_handle_, &dretcode_))
+      throw OSError("Failed during call to GetExitCodeProcess", 0);
+  CloseHandle(process_handle_);
+  return (int)dretcode_;
 #else
   int ret, status;
   std::tie(ret, status) = util::wait_for_child_exit(child_pid_);
@@ -1059,6 +1121,68 @@ inline int Popen::wait() noexcept(false)
 #endif
 }
+inline int Popen::poll() noexcept(false)
+{
+#ifdef __USING_WINDOWS__
+  int ret = WaitForSingleObject(process_handle_, 0);
+  if (ret != WAIT_OBJECT_0) return -1;
+  DWORD dretcode_;
+  if (FALSE == GetExitCodeProcess(process_handle_, &dretcode_))
+      throw OSError("GetExitCodeProcess", 0);
+  retcode_ = (int)dretcode_;
+  CloseHandle(process_handle_);
+  return retcode_;
+#else
+  if (!child_created_) return -1; // TODO: ??
+  int status;
+  // Returns zero if child is still running
+  int ret = waitpid(child_pid_, &status, WNOHANG);
+  if (ret == 0) return -1;
+  if (ret == child_pid_) {
+    if (WIFSIGNALED(status)) {
+      retcode_ = WTERMSIG(status);
+    } else if (WIFEXITED(status)) {
+      retcode_ = WEXITSTATUS(status);
+    } else {
+      retcode_ = 255;
+    }
+    return retcode_;
+  }
+  if (ret == -1) {
+    // From subprocess.py
+    // This happens if SIGCHLD is set to be ignored
+    // or waiting for child process has otherwise been disabled
+    // for our process. This child is dead, we cannot get the
+    // status.
+    if (errno == ECHILD) retcode_ = 0;
+    else throw OSError("waitpid failed", errno);
+  } else {
+    retcode_ = ret;
+  }
+  return retcode_;
+#endif
+}
+inline void Popen::kill(int sig_num)
+{
+#ifdef __USING_WINDOWS__
+  if (!TerminateProcess(this->process_handle_, (UINT)sig_num)) {
+    throw OSError("TerminateProcess", 0);
+  }
+#else
+  ::kill(child_pid_, sig_num);
+#endif
+}
 inline void Popen::execute_process() noexcept(false)
 {
 #ifdef __USING_WINDOWS__
@@ -1071,11 +1195,16 @@ inline void Popen::execute_process() noexcept(false)
   std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
   std::wstring argument;
   std::wstring command_line;
+  bool first_arg = true;
   for (auto arg : this->vargs_) {
+    if (!first_arg) {
+      command_line += L" ";
+    } else {
+      first_arg = false;
+    }
     argument = converter.from_bytes(arg);
     util::quote_argument(argument, command_line, false);
-    command_line += L" ";
   }
   // CreateProcessW can modify szCmdLine so we allocate needed memory
@@ -1156,36 +1285,40 @@ inline void Popen::execute_process() noexcept(false)
   child_pid_ = fork();
   if (child_pid_ < 0) {
-    close(err_rd_pipe);
-    close(err_wr_pipe);
+    subprocess_close(err_rd_pipe);
+    subprocess_close(err_wr_pipe);
     throw OSError("fork failed", errno);
   }
+  child_created_ = true;
   if (child_pid_ == 0)
   {
     // Close descriptors belonging to parent
     stream_.close_parent_fds();
     //Close the read end of the error pipe
-    close(err_rd_pipe);
+    subprocess_close(err_rd_pipe);
     detail::Child chld(this, err_wr_pipe);
     chld.execute_child();
   }