+++ /dev/null
-// -*- 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
Code Review / stor4nfv.git / blobdiff