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Major signal overhaul.  We no longer longjmp all over the place.
Instead, routines responsible to gathering user input (or in some
cases outputting data) catch the signals and set flags as needed.
Because of this some handlers are install without the SA_RESTART
flag so syscalls are not restarted and we can check the flag.  All
signal handlers are now safe.

This should make the flow of control a bit more grokable but the
code is still ugly.

/*	$OpenBSD: lex.c,v 1.25 2001/11/20 20:50:00 millert Exp $	*/
/*	$NetBSD: lex.c,v 1.10 1997/05/17 19:55:13 pk Exp $	*/

/*
 * Copyright (c) 1980, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
#if 0
static char sccsid[] = "@(#)lex.c	8.2 (Berkeley) 4/20/95";
#else
static char rcsid[] = "$OpenBSD: lex.c,v 1.25 2001/11/20 20:50:00 millert Exp $";
#endif
#endif /* not lint */

#include "rcv.h"
#include <errno.h>
#include <fcntl.h>
#include "extern.h"

/*
 * Mail -- a mail program
 *
 * Lexical processing of commands.
 */

char	*prompt = "& ";

const struct cmd *com;	/* command we are running */

/*
 * Set up editing on the given file name.
 * If the first character of name is %, we are considered to be
 * editing the file, otherwise we are reading our mail which has
 * signficance for mbox and so forth.
 */
int
setfile(name)
	char *name;
{
	FILE *ibuf;
	int i, fd;
	struct stat stb;
	char isedit = *name != '%';
	char *who = name[1] ? name + 1 : myname;
	char tempname[PATHSIZE];
	static int shudclob;

	if ((name = expand(name)) == NULL)
		return(-1);

	if ((ibuf = Fopen(name, "r")) == NULL) {
		if (!isedit && errno == ENOENT)
			goto nomail;
		warn("%s", name);
		return(-1);
	}

	if (fstat(fileno(ibuf), &stb) < 0) {
		warn("fstat");
		(void)Fclose(ibuf);
		return(-1);
	}

	switch (stb.st_mode & S_IFMT) {
	case S_IFDIR:
		(void)Fclose(ibuf);
		errno = EISDIR;
		warn("%s", name);
		return(-1);

	case S_IFREG:
		break;

	default:
		(void)Fclose(ibuf);
		errno = EINVAL;
		warn("%s", name);
		return(-1);
	}

	/*
	 * Looks like all will be well.  We must now relinquish our
	 * hold on the current set of stuff.  Must hold signals
	 * while we are reading the new file, else we will ruin
	 * the message[] data structure.
	 */

	holdsigs();
	if (shudclob)
		quit();

	/*
	 * Copy the messages into /tmp
	 * and set pointers.
	 */

	readonly = 0;
	if ((i = open(name, 1)) < 0)
		readonly++;
	else
		(void)close(i);
	if (shudclob) {
		(void)fclose(itf);
		(void)fclose(otf);
	}
	shudclob = 1;
	edit = isedit;
	strcpy(prevfile, mailname);
	if (name != mailname) {
		strncpy(mailname, name, sizeof(mailname) - 1);
		mailname[sizeof(mailname) - 1] = '\0';
	}
	mailsize = fsize(ibuf);
	(void)snprintf(tempname, sizeof(tempname),
	    "%s/mail.RxXXXXXXXXXX", tmpdir);
	if ((fd = mkstemp(tempname)) == -1 ||
	    (otf = fdopen(fd, "w")) == NULL)
		err(1, "%s", tempname);
	(void)fcntl(fileno(otf), F_SETFD, 1);
	if ((itf = fopen(tempname, "r")) == NULL)
		err(1, "%s", tempname);
	(void)fcntl(fileno(itf), F_SETFD, 1);
	(void)rm(tempname);
	setptr(ibuf, 0);
	setmsize(msgCount);
	/*
	 * New mail may have arrived while we were reading
	 * the mail file, so reset mailsize to be where
	 * we really are in the file...
	 */
	mailsize = ftell(ibuf);
	(void)Fclose(ibuf);
	relsesigs();
	sawcom = 0;
	if (!edit && msgCount == 0) {
nomail:
		fprintf(stderr, "No mail for %s\n", who);
		return(-1);
	}
	return(0);
}

/*
 * Incorporate any new mail that has arrived since we first
 * started reading mail.
 */
int
incfile()
{
	int newsize;
	int omsgCount = msgCount;
	FILE *ibuf;

	ibuf = Fopen(mailname, "r");
	if (ibuf == NULL)
		return(-1);
	holdsigs();
	if (!spool_lock()) {
		(void)Fclose(ibuf);
		relsesigs();
		return(-1);
	}
	newsize = fsize(ibuf);
	/* make sure mail box has grown and is non-empty */
	if (newsize == 0 || newsize <= mailsize) {
		(void)Fclose(ibuf);
		spool_unlock();
		relsesigs();
		return(newsize == mailsize ? 0 : -1);
	}
	setptr(ibuf, mailsize);
	setmsize(msgCount);
	mailsize = ftell(ibuf);
	(void)Fclose(ibuf);
	spool_unlock();
	relsesigs();
	return(msgCount - omsgCount);
}


int	*msgvec;
int	reset_on_stop;			/* reset prompt if stopped */

/*
 * Interpret user commands one by one.  If standard input is not a tty,
 * print no prompt.
 */
void
commands()
{
	int n, sig, *sigp;
	int eofloop = 0;
	char linebuf[LINESIZE];

	prompt:
	for (;;) {
		/*
		 * Print the prompt, if needed.  Clear out
		 * string space, and flush the output.
		 */
		if (!sourcing && value("interactive") != NULL) {
			if ((value("autoinc") != NULL) && (incfile() > 0))
				puts("New mail has arrived.");
			reset_on_stop = 1;
			printf("%s", prompt);
		}
		fflush(stdout);
		sreset();
		/*
		 * Read a line of commands from the current input
		 * and handle end of file specially.
		 */
		n = 0;
		sig = 0;
		sigp = sourcing ? NULL : &sig;
		for (;;) {
			if (readline(input, &linebuf[n], LINESIZE - n, sigp) < 0) {
				if (sig) {
					if (sig == SIGINT)
						dointr();
					else if (sig == SIGHUP)
						/* nothing to do? */
						exit(1);
					else {
						/* Stopped by job control */
						(void)kill(0, sig);
						if (reset_on_stop)
							reset_on_stop = 0;
					}
					goto prompt;
				}
				if (n == 0)
					n = -1;
				break;
			}
			if ((n = strlen(linebuf)) == 0)
				break;
			n--;
			if (linebuf[n] != '\\')
				break;
			linebuf[n++] = ' ';
		}
		reset_on_stop = 0;
		if (n < 0) {
				/* eof */
			if (loading)
				break;
			if (sourcing) {
				unstack();
				continue;
			}
			if (value("interactive") != NULL &&
			    value("ignoreeof") != NULL &&
			    ++eofloop < 25) {
				puts("Use \"quit\" to quit.");
				continue;
			}
			break;
		}
		eofloop = 0;
		if (execute(linebuf, 0))
			break;
	}
}

/*
 * Execute a single command.
 * Command functions return 0 for success, 1 for error, and -1
 * for abort.  A 1 or -1 aborts a load or source.  A -1 aborts
 * the interactive command loop.
 * Contxt is non-zero if called while composing mail.
 */
int
execute(linebuf, contxt)
	char linebuf[];
	int contxt;
{
	char word[LINESIZE];
	char *arglist[MAXARGC];
	char *cp, *cp2;
	int c, muvec[2];
	int e = 1;

	com = NULL;

	/*
	 * Strip the white space away from the beginning
	 * of the command, then scan out a word, which
	 * consists of anything except digits and white space.
	 *
	 * Handle ! escapes differently to get the correct
	 * lexical conventions.
	 */

	for (cp = linebuf; isspace(*cp); cp++)
		;
	if (*cp == '!') {
		if (sourcing) {
			puts("Can't \"!\" while sourcing");
			goto out;
		}
		shell(cp+1);
		return(0);
	}
	cp2 = word;
	while (*cp && strchr(" \t0123456789$^.:/-+*'\"", *cp) == NULL)
		*cp2++ = *cp++;
	*cp2 = '\0';

	/*
	 * Look up the command; if not found, bitch.
	 * Normally, a blank command would map to the
	 * first command in the table; while sourcing,
	 * however, we ignore blank lines to eliminate
	 * confusion.
	 */

	if (sourcing && *word == '\0')
		return(0);
	com = lex(word);
	if (com == NONE) {
		printf("Unknown command: \"%s\"\n", word);
		goto out;
	}

	/*
	 * See if we should execute the command -- if a conditional
	 * we always execute it, otherwise, check the state of cond.
	 */

	if ((com->c_argtype & F) == 0)
		if ((cond == CRCV && !rcvmode) || (cond == CSEND && rcvmode))
			return(0);

	/*
	 * Process the arguments to the command, depending
	 * on the type he expects.  Default to an error.
	 * If we are sourcing an interactive command, it's
	 * an error.
	 */

	if (!rcvmode && (com->c_argtype & M) == 0) {
		printf("May not execute \"%s\" while sending\n",
		    com->c_name);
		goto out;
	}
	if (sourcing && com->c_argtype & I) {
		printf("May not execute \"%s\" while sourcing\n",
		    com->c_name);
		goto out;
	}
	if (readonly && com->c_argtype & W) {
		printf("May not execute \"%s\" -- message file is read only\n",
		   com->c_name);
		goto out;
	}
	if (contxt && com->c_argtype & R) {
		printf("Cannot recursively invoke \"%s\"\n", com->c_name);
		goto out;
	}
	switch (com->c_argtype & ~(F|P|I|M|T|W|R)) {
	case MSGLIST|STRLIST:
		/*
		 * A message list defaulting to nearest forward
		 * legal message.
		 */
		if (msgvec == 0) {
			puts("Illegal use of \"message list\"");
			break;
		}
		/*
		 * remove leading blanks.
		 */
		while (isspace(*cp))
			cp++;

		if (isdigit(*cp) || *cp == ':') {
			if ((c = getmsglist(cp, msgvec, com->c_msgflag)) < 0)
				break;
			/* position to next space - past the message list */
			while (!isspace(*cp))
				cp++;
			/* position to next non-space */
			while (isspace(*cp))
				cp++;
		} else {
			c = 0; /* no message list */
		}

		if (c  == 0) {
			*msgvec = first(com->c_msgflag,
				com->c_msgmask);
			msgvec[1] = NULL;
		}
		if (*msgvec == NULL) {
			puts("No applicable messages");
			break;
		}
		/*
		 * Just the straight string, with
		 * leading blanks removed.
		 */
		while (isspace(*cp))
			cp++;

		e = (*com->c_func2)(msgvec, cp);
		break;

	case MSGLIST:
		/*
		 * A message list defaulting to nearest forward
		 * legal message.
		 */
		if (msgvec == 0) {
			puts("Illegal use of \"message list\"");
			break;
		}
		if ((c = getmsglist(cp, msgvec, com->c_msgflag)) < 0)
			break;
		if (c  == 0) {
			*msgvec = first(com->c_msgflag,
				com->c_msgmask);
			msgvec[1] = NULL;
		}
		if (*msgvec == NULL) {
			puts("No applicable messages");
			break;
		}
		e = (*com->c_func)(msgvec);
		break;

	case NDMLIST:
		/*
		 * A message list with no defaults, but no error
		 * if none exist.
		 */
		if (msgvec == 0) {
			puts("Illegal use of \"message list\"");
			break;
		}
		if (getmsglist(cp, msgvec, com->c_msgflag) < 0)
			break;
		e = (*com->c_func)(msgvec);
		break;

	case STRLIST:
		/*
		 * Just the straight string, with
		 * leading blanks removed.
		 */
		while (isspace(*cp))
			cp++;
		e = (*com->c_func)(cp);
		break;

	case RAWLIST:
		/*
		 * A vector of strings, in shell style.
		 */
		if ((c = getrawlist(cp, arglist,
				sizeof(arglist) / sizeof(*arglist))) < 0)
			break;
		if (c < com->c_minargs) {
			printf("%s requires at least %d arg(s)\n",
				com->c_name, com->c_minargs);
			break;
		}
		if (c > com->c_maxargs) {
			printf("%s takes no more than %d arg(s)\n",
				com->c_name, com->c_maxargs);
			break;
		}
		e = (*com->c_func)(arglist);
		break;

	case NOLIST:
		/*
		 * Just the constant zero, for exiting,
		 * eg.
		 */
		e = (*com->c_func)(0);
		break;

	default:
		errx(1, "Unknown argtype");
	}

out:
	/*
	 * Exit the current source file on
	 * error.
	 */
	if (e) {
		if (e < 0)
			return(1);
		if (loading)
			return(1);
		if (sourcing)
			unstack();
		return(0);
	}
	if (com == NULL)
		return(0);
	if (value("autoprint") != NULL && com->c_argtype & P)
		if ((dot->m_flag & MDELETED) == 0) {
			muvec[0] = dot - &message[0] + 1;
			muvec[1] = 0;
			type(muvec);
		}
	if (!sourcing && (com->c_argtype & T) == 0)
		sawcom = 1;
	return(0);
}

/*
 * Set the size of the message vector used to construct argument
 * lists to message list functions.
 */
void
setmsize(sz)
	int sz;
{

	if (msgvec != 0)
		(void)free(msgvec);
	msgvec = (int *)calloc(sz + 1, sizeof(*msgvec));
}

/*
 * Find the correct command in the command table corresponding
 * to the passed command "word"
 */

const struct cmd *
lex(word)
	char word[];
{
	extern const struct cmd cmdtab[];
	const struct cmd *cp;

	if (word[0] == '#')
		word = "#";
	for (cp = &cmdtab[0]; cp->c_name != NULL; cp++)
		if (isprefix(word, cp->c_name))
			return(cp);
	return(NONE);
}

/*
 * Determine if as1 is a valid prefix of as2.
 * Return true if yep.
 */
int
isprefix(as1, as2)
	char *as1, *as2;
{
	char *s1, *s2;

	s1 = as1;
	s2 = as2;
	while (*s1++ == *s2)
		if (*s2++ == '\0')
			return(1);
	return(*--s1 == '\0');
}

/*
 * The following gets called on receipt of an interrupt.  This is
 * to abort printout of a command, mainly.
 * Dispatching here when command() is inactive crashes rcv.
 * Close all open files except 0, 1, 2, and the temporary.
 * Also, unstack all source files.
 */

int	inithdr;			/* am printing startup headers */

void
dointr()
{

	noreset = 0;
	if (!inithdr)
		sawcom++;
	inithdr = 0;
	while (sourcing)
		unstack();

	close_all_files();

	if (image >= 0) {
		(void)close(image);
		image = -1;
	}
	fputs("Interrupt\n", stderr);
}

/*
 * Announce the presence of the current Mail version,
 * give the message count, and print a header listing.
 */
void
announce()
{
	int vec[2], mdot;

	mdot = newfileinfo(0);
	vec[0] = mdot;
	vec[1] = 0;
	dot = &message[mdot - 1];
	if (msgCount > 0 && value("noheader") == NULL) {
		inithdr++;
		headers(vec);
		inithdr = 0;
	}
}

/*
 * Announce information about the file we are editing.
 * Return a likely place to set dot.
 */
int
newfileinfo(omsgCount)
	int omsgCount;
{
	struct message *mp;
	int u, n, mdot, d, s;
	char fname[PATHSIZE], zname[PATHSIZE], *ename;

	for (mp = &message[omsgCount]; mp < &message[msgCount]; mp++)
		if (mp->m_flag & MNEW)
			break;
	if (mp >= &message[msgCount])
		for (mp = &message[omsgCount]; mp < &message[msgCount]; mp++)
			if ((mp->m_flag & MREAD) == 0)
				break;
	if (mp < &message[msgCount])
		mdot = mp - &message[0] + 1;
	else
		mdot = omsgCount + 1;
	s = d = 0;
	for (mp = &message[0], n = 0, u = 0; mp < &message[msgCount]; mp++) {
		if (mp->m_flag & MNEW)
			n++;
		if ((mp->m_flag & MREAD) == 0)
			u++;
		if (mp->m_flag & MDELETED)
			d++;
		if (mp->m_flag & MSAVED)
			s++;
	}
	ename = mailname;
	if (getfold(fname, sizeof(fname)) >= 0) {
		strncat(fname, "/", sizeof(fname) - strlen(fname) - 1);
		if (strncmp(fname, mailname, strlen(fname)) == 0) {
			(void)snprintf(zname, sizeof(zname), "+%s",
			    mailname + strlen(fname));
			ename = zname;
		}
	}
	printf("\"%s\": ", ename);
	if (msgCount == 1)
		fputs("1 message", stdout);
	else
		printf("%d messages", msgCount);
	if (n > 0)
		printf(" %d new", n);
	if (u-n > 0)
		printf(" %d unread", u);
	if (d > 0)
		printf(" %d deleted", d);
	if (s > 0)
		printf(" %d saved", s);
	if (readonly)
		fputs(" [Read only]", stdout);
	putchar('\n');
	return(mdot);
}

/*
 * Print the current version number.
 */

/*ARGSUSED*/
int
pversion(v)
	void *v;
{
	extern char *version;

	printf("Version %s\n", version);
	return(0);
}

/*
 * Load a file of user definitions.
 */
void
load(name)
	char *name;
{
	FILE *in, *oldin;

	if ((in = Fopen(name, "r")) == NULL)
		return;
	oldin = input;
	input = in;
	loading = 1;
	sourcing = 1;
	commands();
	loading = 0;
	sourcing = 0;
	input = oldin;
	(void)Fclose(in);
}