--- /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