IABSD.fr/src/usr.bin/script/script.c

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• Author : deraadt
  Date : 2019-06-28 13:34:58
  Hash : 3aaa63eb
  Message : When system calls indicate an error they return -1, not some arbitrary value < 0. errno is only updated in this case. Change all (most?) callers of syscalls to follow this better, and let's see if this strictness helps us in the future.

• usr.bin/script/script.c

• /*	$OpenBSD: script.c,v 1.35 2019/06/28 13:35:03 deraadt Exp $	*/
  /*	$NetBSD: script.c,v 1.3 1994/12/21 08:55:43 jtc Exp $	*/
  
  /*
   * Copyright (c) 2001 Theo de Raadt
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  /*
   * Copyright (c) 1980, 1992, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <sys/stat.h>
  #include <sys/ioctl.h>
  #include <sys/time.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <paths.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <termios.h>
  #include <unistd.h>
  
  #include <util.h>
  #include <err.h>
  
  FILE	*fscript;
  int	master, slave;
  volatile sig_atomic_t child;
  pid_t	subchild;
  char	*fname;
  
  volatile sig_atomic_t dead;
  volatile sig_atomic_t sigdeadstatus;
  volatile sig_atomic_t flush;
  
  struct	termios tt;
  int		istty;
  
  __dead void done(int);
  void dooutput(void);
  void doshell(char *);
  void fail(void);
  void finish(int);
  void scriptflush(int);
  void handlesigwinch(int);
  
  int
  main(int argc, char *argv[])
  {
  	extern char *__progname;
  	struct sigaction sa;
  	struct winsize win;
  	char ibuf[BUFSIZ];
  	char *cmd;
  	ssize_t cc, off;
  	int aflg, ch;
  
  	cmd = NULL;
  	aflg = 0;
  	while ((ch = getopt(argc, argv, "ac:")) != -1)
  		switch(ch) {
  		case 'a':
  			aflg = 1;
  			break;
  		case 'c':
  			cmd = optarg;
  			break;
  		default:
  			fprintf(stderr, "usage: %s [-a] [-c command] [file]\n",
  			    __progname);
  			exit(1);
  		}
  	argc -= optind;
  	argv += optind;
  
  	if (argc > 0)
  		fname = argv[0];
  	else
  		fname = "typescript";
  
  	if ((fscript = fopen(fname, aflg ? "a" : "w")) == NULL)
  		err(1, "%s", fname);
  
  	if (isatty(0)) {
  		if (tcgetattr(STDIN_FILENO, &tt) == 0 &&
  		    ioctl(STDIN_FILENO, TIOCGWINSZ, &win) == 0)
  			istty = 1;
  	}
  	if (openpty(&master, &slave, NULL, &tt, &win) == -1)
  		err(1, "openpty");
  
  	(void)printf("Script started, output file is %s\n", fname);
  	if (istty) {
  		struct termios rtt = tt;
  
  		cfmakeraw(&rtt);
  		rtt.c_lflag &= ~ECHO;
  		(void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
  	}
  
  	bzero(&sa, sizeof sa);
  	sigemptyset(&sa.sa_mask);
  	sa.sa_handler = handlesigwinch;
  	sa.sa_flags = SA_RESTART;
  	(void)sigaction(SIGWINCH, &sa, NULL);
  
  	child = fork();
  	if (child == -1) {
  		warn("fork");
  		fail();
  	}
  	if (child == 0) {
  		subchild = child = fork();
  		if (child == -1) {
  			warn("fork");
  			fail();
  		}
  		if (child)
  			dooutput();
  		else
  			doshell(cmd);
  	}
  
  	bzero(&sa, sizeof sa);
  	sigemptyset(&sa.sa_mask);
  	sa.sa_handler = finish;
  	(void)sigaction(SIGCHLD, &sa, NULL);
  
  	if (pledge("stdio proc tty", NULL) == -1)
  		err(1, "pledge");
  
  	(void)fclose(fscript);
  	while (1) {
  		if (dead)
  			break;
  		cc = read(STDIN_FILENO, ibuf, BUFSIZ);
  		if (cc == -1 && errno == EINTR)
  			continue;
  		if (cc <= 0)
  			break;
  		for (off = 0; off < cc; ) {
  			ssize_t n = write(master, ibuf + off, cc - off);
  			if (n == -1 && errno != EAGAIN)
  				break;
  			if (n == 0)
  				break;	/* skip writing */
  			if (n > 0)
  				off += n;
  		}
  	}
  	done(sigdeadstatus);
  }
  
  void
  finish(int signo)
  {
  	int save_errno = errno;
  	int status, e = 1;
  	pid_t pid;
  
  	while ((pid = wait3(&status, WNOHANG, 0)) > 0) {
  		if (pid == (pid_t)child) {
  			if (WIFEXITED(status))
  				e = WEXITSTATUS(status);
  		}
  	}
  	dead = 1;
  	sigdeadstatus = e;
  	errno = save_errno;
  }
  
  void
  handlesigwinch(int signo)
  {
  	int save_errno = errno;
  	struct winsize win;
  	pid_t pgrp;
  
  	if (ioctl(STDIN_FILENO, TIOCGWINSZ, &win) != -1) {
  		ioctl(slave, TIOCSWINSZ, &win);
  		if (ioctl(slave, TIOCGPGRP, &pgrp) != -1)
  			killpg(pgrp, SIGWINCH);
  	}
  	errno = save_errno;
  }
  
  void
  dooutput(void)
  {
  	struct sigaction sa;
  	struct itimerval value;
  	sigset_t blkalrm;
  	char obuf[BUFSIZ];
  	time_t tvec;
  	ssize_t outcc = 0, cc, off;
  
  	(void)close(STDIN_FILENO);
  	tvec = time(NULL);
  	(void)fprintf(fscript, "Script started on %s", ctime(&tvec));
  
  	sigemptyset(&blkalrm);
  	sigaddset(&blkalrm, SIGALRM);
  	bzero(&sa, sizeof sa);
  	sigemptyset(&sa.sa_mask);
  	sa.sa_handler = scriptflush;
  	(void)sigaction(SIGALRM, &sa, NULL);
  
  	bzero(&sa, sizeof sa);
  	sigemptyset(&sa.sa_mask);
  	sa.sa_handler = SIG_IGN;
  	(void)sigaction(SIGCHLD, &sa, NULL);
  
  	if (pledge("stdio proc", NULL) == -1)
  		err(1, "pledge");
  
  	value.it_interval.tv_sec = 30;
  	value.it_interval.tv_usec = 0;
  	value.it_value = value.it_interval;
  	(void)setitimer(ITIMER_REAL, &value, NULL);
  	for (;;) {
  		if (flush) {
  			if (outcc) {
  				(void)fflush(fscript);
  				outcc = 0;
  			}
  			flush = 0;
  		}
  		cc = read(master, obuf, sizeof (obuf));
  		if (cc == -1 && errno == EINTR)
  			continue;
  		if (cc <= 0)
  			break;
  		sigprocmask(SIG_BLOCK, &blkalrm, NULL);
  		for (off = 0; off < cc; ) {
  			ssize_t n = write(STDOUT_FILENO, obuf + off, cc - off);
  			if (n == -1 && errno != EAGAIN)
  				break;
  			if (n == 0)
  				break;	/* skip writing */
  			if (n > 0)
  				off += n;
  		}
  		(void)fwrite(obuf, 1, cc, fscript);
  		outcc += cc;
  		sigprocmask(SIG_UNBLOCK, &blkalrm, NULL);
  	}
  	done(0);
  }
  
  void
  scriptflush(int signo)
  {
  	flush = 1;
  }
  
  void
  doshell(char *cmd)
  {
  	char *shell;
  	char *argp[] = {"sh", "-c", NULL, NULL};
  
  	shell = getenv("SHELL");
  	if (shell == NULL)
  		shell = _PATH_BSHELL;
  
  	(void)close(master);
  	(void)fclose(fscript);
  	login_tty(slave);
  
  	if (cmd != NULL) {
  		argp[2] = cmd;
  		execv(_PATH_BSHELL, argp);
  		warn("unable to execute %s", _PATH_BSHELL);
  	} else {
  		execl(shell, shell, "-i", (char *)NULL);
  		warn("%s", shell);
  	}
  	fail();
  }
  
  void
  fail(void)
  {
  
  	(void)kill(0, SIGTERM);
  	done(1);
  }
  
  void
  done(int eval)
  {
  	time_t tvec;
  
  	if (subchild) {
  		tvec = time(NULL);
  		(void)fprintf(fscript,"\nScript done on %s", ctime(&tvec));
  		(void)fclose(fscript);
  		(void)close(master);
  	} else {
  		if (istty)
  			(void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &tt);
  		(void)printf("Script done, output file is %s\n", fname);
  	}
  	exit(eval);
  }