MCOL-4170 Refactor services/systemd units to finish their bootstrap ...

utils/common/pipe.h

@@ -0,0 +1,97 @@
+/* Copyright (C) 2020 MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+#ifndef PIPE_H_INCLUDED
+#define PIPE_H_INCLUDED
+
+/*
+  A helper class to hold the file descriptors returned from a pipe() call.
+*/
+class Pipe
+{
+  int fd[2];
+public:
+  Pipe()
+  {
+    fd[0]= 0;
+    fd[1]= 0;
+  }
+  ~Pipe()
+  {
+    close();
+  }
+  bool is_open_for_read() const
+  {
+    return fd[0] > 0;
+  }
+  bool is_open_for_write() const
+  {
+    return fd[1] > 0;
+  }
+  bool open()
+  {
+    return ::pipe(fd) == -1;
+  }
+  bool init() // TODO: remove this
+  {
+    return open();
+  }
+  ssize_t read(char *str, size_t nbytes)
+  {
+    return ::read(fd[0], str, nbytes);
+  }
+  ssize_t readtm(const struct timeval &tv, void *buf, size_t nbytes)
+  {
+      fd_set rfds;
+      FD_ZERO(&rfds);
+      FD_SET(fd[0], &rfds);
+      struct timeval tmptv = tv;
+      int retval = select(fd[0] + 1, &rfds, NULL, NULL, &tmptv);
+      if (retval == -1)
+          return -1;
+      if (!retval)
+      {
+        errno= ETIME;
+        return -1;
+      }
+      return ::read(fd[0], buf, nbytes);
+  }
+  ssize_t write(const char *str, size_t nbytes)
+  {
+    return ::write(fd[1], str, nbytes);
+  }
+  ssize_t write(const std::string &str)
+  {
+    return write(str.data(), str.length());
+  }
+  void close()
+  {
+    if (fd[0])
+    {
+      ::close(fd[0]);
+      fd[0]= 0;
+    }
+    if (fd[1])
+    {
+      ::close(fd[1]);
+      fd[1]= 0;
+    }
+  }
+};
+
+
+#endif // PIPE_H_INCLUDED