After a simplistic rewrite, signal flags were not being noticed until a

succesfull read operation.  To avoid this, we must use SA_RESTART, and
rewrite most of the guts to handle interrupted read, write, etc, even being
careful to check what library routines are called.... input from millert,
markus, and espie

1 files changed, 104 insertions, 48 deletions

diff --git a/usr.bin/script/script.c b/usr.bin/script/script.c
index 972a1cf405a..f530a6cdd73 100644
--- a/usr.bin/script/script.c
+++ b/usr.bin/script/script.c
@@ -1,7 +1,32 @@
-/*	$OpenBSD: script.c,v 1.15 2001/07/09 07:04:52 deraadt Exp $	*/
+/*	$OpenBSD: script.c,v 1.16 2001/11/18 23:51:57 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.
  *
@@ -44,7 +69,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)script.c	8.1 (Berkeley) 6/6/93";
 #endif
-static char rcsid[] = "$OpenBSD: script.c,v 1.15 2001/07/09 07:04:52 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: script.c,v 1.16 2001/11/18 23:51:57 deraadt Exp $";
 #endif /* not lint */
 
 #include <sys/types.h>
@@ -69,31 +94,34 @@ static char rcsid[] = "$OpenBSD: script.c,v 1.15 2001/07/09 07:04:52 deraadt Exp
 
 FILE	*fscript;
 int	master, slave;
-int	child, subchild;
-int	outcc;
+pid_t	child, subchild;
 char	*fname;
 
-struct	termios tt;
+volatile sig_atomic_t dead;
+volatile sig_atomic_t sigdeadstatus;
+volatile sig_atomic_t flush;
 
-__dead	void done __P((int));
-	void dooutput __P((void));
-	void doshell __P((void));
-	void fail __P((void));
-	void finish __P((int));
-	void scriptflush __P((int));
-	void handlesigwinch __P((int));
+struct	termios tt;
 
+__dead void done __P((int));
+void dooutput __P((void));
+void doshell __P((void));
+void fail __P((void));
+void finish __P((int));
+void scriptflush __P((int));
+void handlesigwinch __P((int));
 
 int
 main(argc, argv)
 	int argc;
 	char *argv[];
 {
-	register int cc;
+	struct sigaction sa;
 	struct termios rtt;
 	struct winsize win;
-	int aflg, ch;
 	char ibuf[BUFSIZ];
+	ssize_t cc, off;
+	int aflg, ch;
 
 	aflg = 0;
 	while ((ch = getopt(argc, argv, "a")) != -1)
@@ -101,7 +129,6 @@ main(argc, argv)
 		case 'a':
 			aflg = 1;
 			break;
-		case '?':
 		default:
 			(void)fprintf(stderr, "usage: script [-a] [file]\n");
 			exit(1);
@@ -128,8 +155,15 @@ main(argc, argv)
 	rtt.c_lflag &= ~ECHO;
 	(void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
 
-	(void)signal(SIGWINCH, handlesigwinch);
-	(void)signal(SIGCHLD, finish);
+	bzero(&sa, sizeof sa);
+	sigemptyset(&sa.sa_mask);
+	sa.sa_handler = finish;
+	(void)sigaction(SIGCHLD, &sa, NULL);
+
+	sa.sa_handler = handlesigwinch;
+	sa.sa_flags = SA_RESTART;
+	(void)sigaction(SIGWINCH, &sa, NULL);
+
 	child = fork();
 	if (child < 0) {
 		perror("fork");
@@ -148,31 +182,41 @@ main(argc, argv)
 	}
 
 	(void)fclose(fscript);
-	while ((cc = read(STDIN_FILENO, ibuf, BUFSIZ)) > 0)
-		(void)write(master, ibuf, cc);
-	done(0);
+	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 == 0)
+				break;	/* skip writing */
+			if (n > 0)
+				off += n;
+		}
+	}
+	done(sigdeadstatus);
 }
 
 void
 finish(signo)
 	int signo;
 {
-	register int die, pid;
 	int save_errno = errno;
-	int status, e;
+	int status, e = 1;
+	pid_t pid;
 
-	die = e = 0;
-	while ((pid = wait3(&status, WNOHANG, 0)) > 0)
+	while ((pid = wait3(&status, WNOHANG, 0)) > 0) {
 		if (pid == child) {
-			die = 1;
 			if (WIFEXITED(status))
-                                e = WEXITSTATUS(status);
-                        else
-                                e = 1;
+				e = WEXITSTATUS(status);
 		}
-
-	if (die)
-		done(e);
+	}
+	dead = 1;
+	sigdeadstatus = e;
 	errno = save_errno;
 }
 
@@ -180,14 +224,14 @@ void
 handlesigwinch(signo)
 	int signo;
 {
+	int save_errno = errno;
 	struct winsize win;
 	pid_t pgrp;
-	int save_errno = errno;
 
 	if (ioctl(STDIN_FILENO, TIOCGWINSZ, &win) != -1) {
-	    ioctl(slave, TIOCSWINSZ, &win);
-	    if (ioctl(slave, TIOCGPGRP, &pgrp) != -1)
-	    	killpg(pgrp, SIGWINCH);
+		ioctl(slave, TIOCSWINSZ, &win);
+		if (ioctl(slave, TIOCGPGRP, &pgrp) != -1)
+			killpg(pgrp, SIGWINCH);
 	}
 	errno = save_errno;
 }
@@ -195,43 +239,56 @@ handlesigwinch(signo)
 void
 dooutput()
 {
+	struct sigaction sa;
 	struct itimerval value;
-	register int cc;
-	time_t tvec;
 	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));
 
-	(void)signal(SIGALRM, scriptflush);
+	bzero(&sa, sizeof sa);
+	sigemptyset(&sa.sa_mask);
+	sa.sa_handler = scriptflush;
+	(void)sigaction(SIGALRM, &sa, NULL);
+
 	value.it_interval.tv_sec = SECSPERMIN / 2;
 	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;
-		(void)write(1, obuf, cc);
+		for (off = 0; off < cc; ) {
+			ssize_t n = write(1, obuf + off, cc - off);
+			if (n == 0)
+				break;	/* skip writing */
+			if (n > 0)
+				off += n;
+		}
 		(void)fwrite(obuf, 1, cc, fscript);
 		outcc += cc;
 	}
 	done(0);
 }
 
-/* XXX totally illegal race */
 void
 scriptflush(signo)
 	int signo;
 {
-	int save_errno = errno;
-
-	if (outcc) {
-		(void)fflush(fscript);
-		outcc = 0;
-	}
-	errno = save_errno;
+	flush = 1;
 }
 
 void
@@ -276,4 +333,3 @@ done(eval)
 	}
 	exit(eval);
 }
-