X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Fcommon%2FSubProcess.h;fp=src%2Fceph%2Fsrc%2Fcommon%2FSubProcess.h;h=ce9559c5eeca10dfec77eb15888237431d19a358;hb=812ff6ca9fcd3e629e49d4328905f33eee8ca3f5;hp=0000000000000000000000000000000000000000;hpb=15280273faafb77777eab341909a3f495cf248d9;p=stor4nfv.git

diff --git a/src/ceph/src/common/SubProcess.h b/src/ceph/src/common/SubProcess.h
new file mode 100644
index 0000000..ce9559c
--- /dev/null
+++ b/src/ceph/src/common/SubProcess.h
@@ -0,0 +1,488 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph distributed storage system
+ *
+ * Copyright (C) 2015 Mirantis Inc
+ *
+ * Author: Mykola Golub <mgolub@mirantis.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ */
+
+#ifndef SUB_PROCESS_H
+#define SUB_PROCESS_H
+
+#include <sys/wait.h>
+#include <stdarg.h>
+#include <sstream>
+#include <vector>
+#include <iostream>
+#include <include/assert.h>
+#include <common/errno.h>
+#if defined(__FreeBSD__)
+#include <sys/types.h>
+#include <signal.h>
+#endif
+
+/**
+ * SubProcess:
+ * A helper class to spawn a subprocess.
+ *
+ * Example:
+ *
+ *   SubProcess cat("cat", SubProcess::PIPE, SubProcess::PIPE);
+ *   if (cat.spawn() != 0) {
+ *     std::cerr << "cat failed: " << cat.err() << std::endl;
+ *     return false;
+ *   }
+ *   write_to_fd(cat.get_stdout(), "hello world!\n");
+ *   cat.close_stdout();
+ *   read_from_fd(cat.get_stdin(), buf);
+ *   if (cat.join() != 0) {
+ *     std::cerr << cat.err() << std::endl;
+ *     return false;
+ *   }
+ */
+
+class SubProcess {
+public:
+  enum std_fd_op{
+    KEEP,
+    CLOSE,
+    PIPE
+  };
+public:
+  SubProcess(const char *cmd,
+             std_fd_op stdin_op = CLOSE,
+             std_fd_op stdout_op = CLOSE,
+             std_fd_op stderr_op = CLOSE);
+  virtual ~SubProcess();
+
+  void add_cmd_args(const char *arg, ...);
+  void add_cmd_arg(const char *arg);
+
+  virtual int spawn(); // Returns 0 on success or -errno on failure.
+  virtual int join();  // Returns exit code (0 on success).
+
+  bool is_spawned() const { return pid > 0; }
+
+  int get_stdin() const;
+  int get_stdout() const;
+  int get_stderr() const;
+
+  void close_stdin();
+  void close_stdout();
+  void close_stderr();
+
+  void kill(int signo = SIGTERM) const;
+
+  const std::string err() const;
+
+protected:
+  bool is_child() const { return pid == 0; }
+  virtual void exec();
+
+private:
+  void close(int &fd);
+
+protected:
+  std::string cmd;
+  std::vector<std::string> cmd_args;
+  std_fd_op stdin_op;
+  std_fd_op stdout_op;
+  std_fd_op stderr_op;
+  int stdin_pipe_out_fd;
+  int stdout_pipe_in_fd;
+  int stderr_pipe_in_fd;
+  int pid;
+  std::ostringstream errstr;
+};
+
+class SubProcessTimed : public SubProcess {
+public:
+  SubProcessTimed(const char *cmd, std_fd_op stdin_op = CLOSE,
+		  std_fd_op stdout_op = CLOSE, std_fd_op stderr_op = CLOSE,
+		  int timeout = 0, int sigkill = SIGKILL);
+
+protected:
+  void exec() override;
+
+private:
+  int timeout;
+  int sigkill;
+};
+
+inline SubProcess::SubProcess(const char *cmd_, std_fd_op stdin_op_, std_fd_op stdout_op_, std_fd_op stderr_op_) :
+  cmd(cmd_),
+  cmd_args(),
+  stdin_op(stdin_op_),
+  stdout_op(stdout_op_),
+  stderr_op(stderr_op_),
+  stdin_pipe_out_fd(-1),
+  stdout_pipe_in_fd(-1),
+  stderr_pipe_in_fd(-1),
+  pid(-1),
+  errstr() {
+}
+
+inline SubProcess::~SubProcess() {
+  assert(!is_spawned());
+  assert(stdin_pipe_out_fd == -1);
+  assert(stdout_pipe_in_fd == -1);
+  assert(stderr_pipe_in_fd == -1);
+}
+
+inline void SubProcess::add_cmd_args(const char *arg, ...) {
+  assert(!is_spawned());
+
+  va_list ap;
+  va_start(ap, arg);
+  const char *p = arg;
+  do {
+    add_cmd_arg(p);
+    p = va_arg(ap, const char*);
+  } while (p != NULL);
+  va_end(ap);
+}
+
+inline void SubProcess::add_cmd_arg(const char *arg) {
+  assert(!is_spawned());
+
+  cmd_args.push_back(arg);
+}
+
+inline int SubProcess::get_stdin() const {
+  assert(is_spawned());
+  assert(stdin_op == PIPE);
+
+  return stdin_pipe_out_fd;
+}
+
+inline int SubProcess::get_stdout() const {
+  assert(is_spawned());
+  assert(stdout_op == PIPE);
+
+  return stdout_pipe_in_fd;
+}
+
+inline int SubProcess::get_stderr() const {
+  assert(is_spawned());
+  assert(stderr_op == PIPE);
+
+  return stderr_pipe_in_fd;
+}
+
+inline void SubProcess::close(int &fd) {
+  if (fd == -1)
+    return;
+
+  ::close(fd);
+  fd = -1;
+}
+
+inline void SubProcess::close_stdin() {
+  assert(is_spawned());
+  assert(stdin_op == PIPE);
+
+  close(stdin_pipe_out_fd);
+}
+
+inline void SubProcess::close_stdout() {
+  assert(is_spawned());
+  assert(stdout_op == PIPE);
+
+  close(stdout_pipe_in_fd);
+}
+
+inline void SubProcess::close_stderr() {
+  assert(is_spawned());
+  assert(stderr_op == PIPE);
+
+  close(stderr_pipe_in_fd);
+}
+
+inline void SubProcess::kill(int signo) const {
+  assert(is_spawned());
+
+  int ret = ::kill(pid, signo);
+  assert(ret == 0);
+}
+
+inline const std::string SubProcess::err() const {
+  return errstr.str();
+}
+
+class fd_buf : public std::streambuf {
+  int fd;
+public:
+  fd_buf (int fd) : fd(fd)
+  {}
+protected:
+  int_type overflow (int_type c) override {
+    if (c == EOF) return EOF;
+    char buf = c;
+    if (write (fd, &buf, 1) != 1) {
+      return EOF;
+    }
+    return c;
+  }
+  std::streamsize xsputn (const char* s, std::streamsize count) override {
+    return write(fd, s, count);
+  }
+};
+
+inline int SubProcess::spawn() {
+  assert(!is_spawned());
+  assert(stdin_pipe_out_fd == -1);
+  assert(stdout_pipe_in_fd == -1);
+  assert(stderr_pipe_in_fd == -1);
+
+  enum { IN = 0, OUT = 1 };
+
+  int ipipe[2], opipe[2], epipe[2];
+
+  ipipe[0] = ipipe[1] = opipe[0] = opipe[1] = epipe[0] = epipe[1] = -1;
+
+  int ret = 0;
+
+  if ((stdin_op == PIPE  && ::pipe(ipipe) == -1) ||
+      (stdout_op == PIPE && ::pipe(opipe) == -1) ||
+      (stderr_op == PIPE && ::pipe(epipe) == -1)) {
+    ret = -errno;
+    errstr << "pipe failed: " << cpp_strerror(errno);
+    goto fail;
+  }
+
+  pid = fork();
+
+  if (pid > 0) { // Parent
+    stdin_pipe_out_fd = ipipe[OUT]; close(ipipe[IN ]);
+    stdout_pipe_in_fd = opipe[IN ]; close(opipe[OUT]);
+    stderr_pipe_in_fd = epipe[IN ]; close(epipe[OUT]);
+    return 0;
+  }
+
+  if (pid == 0) { // Child
+    close(ipipe[OUT]);
+    close(opipe[IN ]);
+    close(epipe[IN ]);
+
+    if (ipipe[IN] != -1 && ipipe[IN] != STDIN_FILENO) {
+      ::dup2(ipipe[IN], STDIN_FILENO);
+      close(ipipe[IN]);
+    }
+    if (opipe[OUT] != -1 && opipe[OUT] != STDOUT_FILENO) {
+      ::dup2(opipe[OUT], STDOUT_FILENO);
+      close(opipe[OUT]);
+      static fd_buf buf(STDOUT_FILENO);
+      std::cout.rdbuf(&buf);
+    }
+    if (epipe[OUT] != -1 && epipe[OUT] != STDERR_FILENO) {
+      ::dup2(epipe[OUT], STDERR_FILENO);
+      close(epipe[OUT]);
+      static fd_buf buf(STDERR_FILENO);
+      std::cerr.rdbuf(&buf);
+    }
+
+    int maxfd = sysconf(_SC_OPEN_MAX);
+    if (maxfd == -1)
+      maxfd = 16384;
+    for (int fd = 0; fd <= maxfd; fd++) {
+      if (fd == STDIN_FILENO && stdin_op != CLOSE)
+	continue;
+      if (fd == STDOUT_FILENO && stdout_op != CLOSE)
+	continue;
+      if (fd == STDERR_FILENO && stderr_op != CLOSE)
+	continue;
+      ::close(fd);
+    }
+
+    exec();
+    ceph_abort(); // Never reached
+  }
+
+  ret = -errno;
+  errstr << "fork failed: " << cpp_strerror(errno);
+
+fail:
+  close(ipipe[0]);
+  close(ipipe[1]);
+  close(opipe[0]);
+  close(opipe[1]);
+  close(epipe[0]);
+  close(epipe[1]);
+
+  return ret;
+}
+
+inline void SubProcess::exec() {
+  assert(is_child());
+
+  std::vector<const char *> args;
+  args.push_back(cmd.c_str());
+  for (std::vector<std::string>::iterator i = cmd_args.begin();
+       i != cmd_args.end();
+       i++) {
+    args.push_back(i->c_str());
+  }
+  args.push_back(NULL);
+
+  int ret = execvp(cmd.c_str(), (char * const *)&args[0]);
+  assert(ret == -1);
+
+  std::cerr << cmd << ": exec failed: " << cpp_strerror(errno) << "\n";
+  _exit(EXIT_FAILURE);
+}
+
+inline int SubProcess::join() {
+  assert(is_spawned());
+
+  close(stdin_pipe_out_fd);
+  close(stdout_pipe_in_fd);
+  close(stderr_pipe_in_fd);
+
+  int status;
+
+  while (waitpid(pid, &status, 0) == -1)
+    assert(errno == EINTR);
+
+  pid = -1;
+
+  if (WIFEXITED(status)) {
+    if (WEXITSTATUS(status) != EXIT_SUCCESS)
+      errstr << cmd << ": exit status: " << WEXITSTATUS(status);
+    return WEXITSTATUS(status);
+  }
+  if (WIFSIGNALED(status)) {
+    errstr << cmd << ": got signal: " << WTERMSIG(status);
+    return 128 + WTERMSIG(status);
+  }
+  errstr << cmd << ": waitpid: unknown status returned\n";
+  return EXIT_FAILURE;
+}
+
+inline SubProcessTimed::SubProcessTimed(const char *cmd, std_fd_op stdin_op,
+				 std_fd_op stdout_op, std_fd_op stderr_op,
+				 int timeout_, int sigkill_) :
+  SubProcess(cmd, stdin_op, stdout_op, stderr_op),
+  timeout(timeout_),
+  sigkill(sigkill_) {
+}
+
+static bool timedout = false; // only used after fork
+static void timeout_sighandler(int sig) {
+  timedout = true;
+}
+static void dummy_sighandler(int sig) {}
+
+inline void SubProcessTimed::exec() {
+  assert(is_child());
+
+  if (timeout <= 0) {
+    SubProcess::exec();
+    ceph_abort(); // Never reached
+  }
+
+  sigset_t mask, oldmask;
+  int pid;
+
+  // Restore default action for SIGTERM in case the parent process decided
+  // to ignore it.
+  if (signal(SIGTERM, SIG_DFL) == SIG_ERR) {
+    std::cerr << cmd << ": signal failed: " << cpp_strerror(errno) << "\n";
+    goto fail_exit;
+  }
+  // Because SIGCHLD is ignored by default, setup dummy handler for it,
+  // so we can mask it.
+  if (signal(SIGCHLD, dummy_sighandler) == SIG_ERR) {
+    std::cerr << cmd << ": signal failed: " << cpp_strerror(errno) << "\n";
+    goto fail_exit;
+  }
+  // Setup timeout handler.
+  if (signal(SIGALRM, timeout_sighandler) == SIG_ERR) {
+    std::cerr << cmd << ": signal failed: " << cpp_strerror(errno) << "\n";
+    goto fail_exit;
+  }
+  // Block interesting signals.
+  sigemptyset(&mask);
+  sigaddset(&mask, SIGINT);
+  sigaddset(&mask, SIGTERM);
+  sigaddset(&mask, SIGCHLD);
+  sigaddset(&mask, SIGALRM);
+  if (sigprocmask(SIG_SETMASK, &mask, &oldmask) == -1) {
+    std::cerr << cmd << ": sigprocmask failed: " << cpp_strerror(errno) << "\n";
+    goto fail_exit;
+  }
+
+  pid = fork();
+
+  if (pid == -1) {
+    std::cerr << cmd << ": fork failed: " << cpp_strerror(errno) << "\n";
+    goto fail_exit;
+  }
+
+  if (pid == 0) { // Child
+    // Restore old sigmask.
+    if (sigprocmask(SIG_SETMASK, &oldmask, NULL) == -1) {
+      std::cerr << cmd << ": sigprocmask failed: " << cpp_strerror(errno) << "\n";
+      goto fail_exit;
+    }
+    (void)setpgid(0, 0); // Become process group leader.
+    SubProcess::exec();
+    ceph_abort(); // Never reached
+  }
+
+  // Parent
+  (void)alarm(timeout);
+
+  for (;;) {
+    int signo;
+    if (sigwait(&mask, &signo) == -1) {
+      std::cerr << cmd << ": sigwait failed: " << cpp_strerror(errno) << "\n";
+      goto fail_exit;
+    }
+    switch (signo) {
+    case SIGCHLD:
+      int status;
+      if (waitpid(pid, &status, WNOHANG) == -1) {
+	std::cerr << cmd << ": waitpid failed: " << cpp_strerror(errno) << "\n";
+	goto fail_exit;
+      }
+      if (WIFEXITED(status))
+	_exit(WEXITSTATUS(status));
+      if (WIFSIGNALED(status))
+	_exit(128 + WTERMSIG(status));
+      std::cerr << cmd << ": unknown status returned\n";
+      goto fail_exit;
+    case SIGINT:
+    case SIGTERM:
+      // Pass SIGINT and SIGTERM, which are usually used to terminate
+      // a process, to the child.
+      if (::kill(pid, signo) == -1) {
+	std::cerr << cmd << ": kill failed: " << cpp_strerror(errno) << "\n";
+	goto fail_exit;
+      }
+      continue;
+    case SIGALRM:
+      std::cerr << cmd << ": timed out (" << timeout << " sec)\n";
+      if (::killpg(pid, sigkill) == -1) {
+	std::cerr << cmd << ": kill failed: " << cpp_strerror(errno) << "\n";
+	goto fail_exit;
+      }
+      continue;
+    default:
+      std::cerr << cmd << ": sigwait: invalid signal: " << signo << "\n";
+      goto fail_exit;
+    }
+  }
+
+fail_exit:
+  _exit(EXIT_FAILURE);
+}
+
+#endif