/*
 * zpty.c - sub-processes with pseudo terminals
 *
 * This file is part of zsh, the Z shell.
 *
 * Copyright (c) 2000 Sven Wischnowsky
 * All rights reserved.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and to distribute modified versions of this software for any
 * purpose, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * In no event shall Sven Wischnowsky or the Zsh Development Group be liable
 * to any party for direct, indirect, special, incidental, or consequential
 * damages arising out of the use of this software and its documentation,
 * even if Sven Wischnowsky and the Zsh Development Group have been advised of
 * the possibility of such damage.
 *
 * Sven Wischnowsky and the Zsh Development Group specifically disclaim any
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose.  The software
 * provided hereunder is on an "as is" basis, and Sven Wischnowsky and the
 * Zsh Development Group have no obligation to provide maintenance,
 * support, updates, enhancements, or modifications.
 *
 */

#include "zpty.mdh"
#include "zpty.pro"

/* The number of bytes we normally read when given no pattern and the
 * upper bound on the number of bytes we read (even if we are give a
 * pattern). */

#define READ_MAX (1024 * 1024)

typedef struct ptycmd *Ptycmd;

struct ptycmd {
    Ptycmd next;
    char *name;
    char **args;
    int fd;
    int pid;
    int echo;
    int nblock;
    int fin;
    int read;
    char *old;
    int olen;
};

static Ptycmd ptycmds;

static int
ptynonblock(int fd)
{
#ifdef O_NDELAY
# ifdef O_NONBLOCK
#  define NONBLOCK (O_NDELAY|O_NONBLOCK)
# else /* !O_NONBLOCK */
#  define NONBLOCK O_NDELAY
# endif /* !O_NONBLOCK */
#else /* !O_NDELAY */
# ifdef O_NONBLOCK
#  define NONBLOCK O_NONBLOCK
# else /* !O_NONBLOCK */
#  define NONBLOCK 0
# endif /* !O_NONBLOCK */
#endif /* !O_NDELAY */

#if NONBLOCK
    long mode;

    mode = fcntl(fd, F_GETFL, 0);
    if (mode != -1 && !(mode & NONBLOCK) &&
	!fcntl(fd, F_SETFL, mode | NONBLOCK))
	return 1;

#endif /* NONBLOCK */
    return 0;

#undef NONBLOCK
}

/**/
static int
ptygettyinfo(int fd, struct ttyinfo *ti)
{
    if (fd != -1) {
#ifdef HAVE_TERMIOS_H
# ifdef HAVE_TCGETATTR
	if (tcgetattr(fd, &ti->tio) == -1)
# else
	if (ioctl(fd, TCGETS, &ti->tio) == -1)
# endif
	    return 1;
#else
# ifdef HAVE_TERMIO_H
	ioctl(fd, TCGETA, &ti->tio);
# else
	ioctl(fd, TIOCGETP, &ti->sgttyb);
	ioctl(fd, TIOCLGET, &ti->lmodes);
	ioctl(fd, TIOCGETC, &ti->tchars);
	ioctl(fd, TIOCGLTC, &ti->ltchars);
# endif
#endif
	return 0;
    }
    return 1;
}

/**/
static void
ptysettyinfo(int fd, struct ttyinfo *ti)
{
    if (fd != -1) {
#ifdef HAVE_TERMIOS_H
# ifdef HAVE_TCGETATTR
#  ifndef TCSADRAIN
#   define TCSADRAIN 1	/* XXX Princeton's include files are screwed up */
#  endif
	tcsetattr(fd, TCSADRAIN, &ti->tio);
    /* if (tcsetattr(SHTTY, TCSADRAIN, &ti->tio) == -1) */
# else
	ioctl(fd, TCSETS, &ti->tio);
    /* if (ioctl(SHTTY, TCSETS, &ti->tio) == -1) */
# endif
	/*	zerr("settyinfo: %e",errno)*/ ;
#else
# ifdef HAVE_TERMIO_H
	ioctl(fd, TCSETA, &ti->tio);
# else
	ioctl(fd, TIOCSETN, &ti->sgttyb);
	ioctl(fd, TIOCLSET, &ti->lmodes);
	ioctl(fd, TIOCSETC, &ti->tchars);
	ioctl(fd, TIOCSLTC, &ti->ltchars);
# endif
#endif
    }
}

static Ptycmd
getptycmd(char *name)
{
    Ptycmd p;

    for (p = ptycmds; p; p = p->next)
	if (!strcmp(p->name, name))
	    return p;

    return NULL;
}

#ifdef USE_DEV_PTMX

#ifdef HAVE_SYS_STROPTS_H
#include <sys/stropts.h>
#endif

#if defined(I_FIND) && defined(I_PUSH)
/*
 * These tests are ad hoc.  Unfortunately if you get the wrong ioctl,
 * STREAMS simply hangs up, so there's no obvious way of doing this
 * more systematically.
 *
 * Apparently Solaris needs all three ioctls, but HP-UX doesn't need
 * ttcompat.  The Solaris definition has been extended to all __SVR4
 * as a guess; I have no idea if this is right.
 */
#ifdef __SVR4
#define USE_STREAMS_IOCTLS
#define USE_STREAMS_TTCOMPAT
#endif
#ifdef __hpux
#define USE_STREAMS_IOCTLS
#endif
#endif

static int
get_pty(int master, int *retfd)
{
    static char *name;
    static int mfd, sfd;
#ifdef USE_STREAMS_IOCTLS
    int ret;
#endif

    if (master) {
	if ((mfd = open("/dev/ptmx", O_RDWR|O_NOCTTY)) < 0)
	    return 1;

	if (grantpt(mfd) || unlockpt(mfd) || !(name = ptsname(mfd))) {
	    close(mfd);
	    return 1;
	}
	*retfd = mfd;

	return 0;
    }
    if ((sfd = open(name, O_RDWR
#ifndef __CYGWIN__
		    /* It is not clear whether this flag is actually needed. */
		    |O_NOCTTY
#endif
	)) < 0) {
	close(mfd);
	return 1;
    }
#ifdef USE_STREAMS_IOCTLS
    if ((ret = ioctl(sfd, I_FIND, "ptem")) != 1)
       if (ret == -1 || ioctl(sfd, I_PUSH, "ptem") == -1) {
	   close(mfd);
	   close(sfd);
	   return 1;
       }
    if ((ret = ioctl(sfd, I_FIND, "ldterm")) != 1)
       if (ret == -1 || ioctl(sfd, I_PUSH, "ldterm") == -1) {
	   close(mfd);
	   close(sfd);
	   return 1;
       }
#ifdef USE_STREAMS_TTCOMPAT
    if ((ret = ioctl(sfd, I_FIND, "ttcompat")) != 1)
       if (ret == -1 || ioctl(sfd, I_PUSH, "ttcompat") == -1) {
	   close(mfd);
	   close(sfd);
	   return 1;
       }
#endif
#endif

    *retfd = sfd;

    return 0;
}

#else /* No /dev/ptmx or no pt functions */

static int
get_pty(int master, int *retfd)
{

#ifdef __linux
    static char char1[] = "abcdefghijklmnopqrstuvwxyz";
    static char char2[] = "0123456789abcdef";
#elif defined(__FreeBSD__) || defined(__DragonFly__)
    static char char1[] = "pqrsPQRS";
    static char char2[] = "0123456789abcdefghijklmnopqrstuv";
#else /* __FreeBSD__ || __DragonFly__ */
    static char char1[] = "pqrstuvwxyzPQRST";
    static char char2[] = "0123456789abcdef";
#endif

    static char name[11];
    static int mfd, sfd;
    char *p1, *p2;

    if (master) {
	strcpy(name, "/dev/ptyxx");
#if defined(__BEOS__) || defined(__HAIKU__)
	name[7] = '/';
#endif

	for (p1 = char1; *p1; p1++) {
	    name[8] = *p1;
	    for (p2 = char2; *p2; p2++) {
		name[9] = *p2;
		if ((mfd = open(name, O_RDWR|O_NOCTTY)) >= 0) {
		    *retfd = mfd;

		    return 0;
		}
	    }
	}
    }
    name[5] = 't';
    if ((sfd = open(name, O_RDWR|O_NOCTTY)) >= 0) {
	*retfd = sfd;

	return 0;
    }
    close(mfd);

    return 1;
}

#endif /* /dev/ptmx or alternatives */

static int
newptycmd(char *nam, char *pname, char **args, int echo, int nblock)
{
    Ptycmd p;
    int master, slave, pid, oineval = ineval, ret;
    char *oscriptname = scriptname, syncch;
    Eprog prog;

    /* code borrowed from bin_eval() */
    ineval = !isset(EVALLINENO);
    if (!ineval)
	scriptname = "(zpty)";

    prog = parse_string(zjoin(args, ' ', 1), 0);
    if (!prog) {
	errflag = 0;
	scriptname = oscriptname;
	ineval = oineval;
	return 1;
    }

    if (get_pty(1, &master)) {
	zwarnnam(nam, "can't open pseudo terminal: %e", errno);
	scriptname = oscriptname;
	ineval = oineval;
	return 1;
    }
    if ((pid = fork()) == -1) {
	zwarnnam(nam, "can't create pty command %s: %e", pname, errno);
	close(master);
	scriptname = oscriptname;
	ineval = oineval;
	return 1;
    } else if (!pid) {
	/* This code copied from the clone module, except for getting *
	 * the descriptor from get_pty() and duplicating it to 0/1/2. */

	clearjobtab(0);
	ppid = getppid();
	mypid = getpid();
#ifdef HAVE_SETSID
	if (setsid() != mypid) {
	    zwarnnam(nam, "failed to create new session: %e", errno);
#endif
#ifdef TIOCNOTTY
	    if (ioctl(SHTTY, TIOCNOTTY, 0))
		zwarnnam(nam, "%e", errno);
	    setpgrp(0L, mypid);
#endif
#ifdef HAVE_SETSID
	}
#endif

	if (get_pty(0, &slave))
	    exit(1);
	SHTTY = slave;
	attachtty(mypid);
#ifdef TIOCGWINSZ
	/* Set the window size before associating with the terminal *
	 * so that we don't get hit with a SIGWINCH.  I'm paranoid. */
	if (interact) {
	    struct ttyinfo info;

	    if (ioctl(slave, TIOCGWINSZ, (char *) &info.winsize) == 0) {
		info.winsize.ws_row = zterm_lines;
		info.winsize.ws_col = zterm_columns;
		ioctl(slave, TIOCSWINSZ, (char *) &info.winsize);
	    }
	}
#endif /* TIOCGWINSZ */

	if (!echo) {
	    struct ttyinfo info;

	    if (!ptygettyinfo(slave, &info)) {
#ifdef HAVE_TERMIOS_H
		info.tio.c_lflag &= ~ECHO;
#else
#ifdef HAVE_TERMIO_H
		info.tio.c_lflag &= ~ECHO;
#else
		info.tio.lmodes &= ~ECHO; /**** dunno if this is right */
#endif
#endif
		ptysettyinfo(slave, &info);
	    }
	}

#ifdef TIOCSCTTY
	ioctl(slave, TIOCSCTTY, 0);
#endif

	close(0);
	close(1);
	close(2);

	dup2(slave, 0);
	dup2(slave, 1);
	dup2(slave, 2);

	closem(0);
	close(slave);
	close(master);
	close(coprocin);
	close(coprocout);
	init_io();
	setsparam("TTY", ztrdup(ttystrname));

	opts[INTERACTIVE] = 0;

	syncch = 0;
	do {
	    ret = write(1, &syncch, 1);
	} while (ret != 1 && (
#ifdef EWOULDBLOCK
	    errno == EWOULDBLOCK ||
#else
#ifdef EAGAIN
	    errno == EAGAIN ||
#endif
#endif
	    errno == EINTR));

	execode(prog, 1, 0, "zpty");
	stopmsg = 2;
	mypid = 0; /* trick to ensure we _exit() */
	zexit(lastval, 0);
    }
    master = movefd(master);
    if (master == -1) {
	zerrnam(nam, "cannot duplicate fd %d: %e", master, errno);
	scriptname = oscriptname;
	ineval = oineval;
	return 1;
    }

    p = (Ptycmd) zalloc(sizeof(*p));

    p->name = ztrdup(pname);
    p->args = zarrdup(args);
    p->fd = master;
    p->pid = pid;
    p->echo = echo;
    p->nblock = nblock;
    p->fin = 0;
    p->read = -1;
    p->old = NULL;
    p->olen = 0;

    p->next = ptycmds;
    ptycmds = p;

    if (nblock)
	ptynonblock(master);

    scriptname = oscriptname;
    ineval = oineval;

    do {
	ret = read(master, &syncch, 1);
    } while (ret != 1 && (
#ifdef EWOULDBLOCK
	    errno == EWOULDBLOCK ||
#else
#ifdef EAGAIN
	    errno == EAGAIN ||
#endif
#endif
	    errno == EINTR));

    return 0;
}

static void
deleteptycmd(Ptycmd cmd)
{
    Ptycmd p, q;

    for (q = NULL, p = ptycmds; p != cmd; q = p, p = p->next);

    if (p != cmd)
	return;

    if (q)
	q->next = p->next;
    else
	ptycmds = p->next;

    zsfree(p->name);
    freearray(p->args);

    zclose(cmd->fd);

    /* We kill the process group the command put itself in. */

    kill(-(p->pid), SIGHUP);

    zfree(p, sizeof(*p));
}

static void
deleteallptycmds(void)
{
    Ptycmd p, n;

    for (p = ptycmds; p; p = n) {
	n = p->next;
	deleteptycmd(p);
    }
}

/**** a better process handling would be nice */

static void
checkptycmd(Ptycmd cmd)
{
    char c;
    int r;

    if (cmd->read != -1 || cmd->fin)
	return;
    if ((r = read(cmd->fd, &c, 1)) < 0) {
	if (kill(cmd->pid, 0) < 0) {
	    cmd->fin = 1;
	    zclose(cmd->fd);
	}
	return;
    }
    if (r) cmd->read = (int) c;
}

static int
ptyread(char *nam, Ptycmd cmd, char **args, int noblock, int mustmatch)
{
    int blen, used, seen = 0, ret = 0, matchok = 0;
    char *buf;
    Patprog prog = NULL;

    if (*args && args[1]) {
	char *p;

	if (args[2]) {
	    zwarnnam(nam, "too many arguments");
	    return 1;
	}
	p = dupstring(args[1]);
	tokenize(p);
	remnulargs(p);
	if (!(prog = patcompile(p, PAT_STATIC, NULL))) {
	    zwarnnam(nam, "bad pattern: %s", args[1]);
	    return 1;
	}
    } else
	fflush(stdout);

    if (cmd->old) {
	used = cmd->olen;
	buf = (char *) zhalloc((blen = 256 + used) + 1);
	memcpy(buf, cmd->old, cmd->olen);
	zfree(cmd->old, cmd->olen);
	cmd->old = NULL;
	cmd->olen = 0;
    } else {
	used = 0;
	buf = (char *) zhalloc((blen = 256) + 1);
    }
    if (cmd->read != -1) {
	buf[used] = (char) cmd->read;
	buf[used + 1] = '\0';
	seen = used = 1;
	cmd->read = -1;
    }
    do {
	if (noblock && cmd->read == -1) {
	    int pollret;
	    /*
	     * Check there is data available.  Borrowed from
	     * poll_read() in utils.c and simplified.
	     */
#ifdef HAVE_SELECT
	    fd_set foofd;
	    struct timeval expire_tv;
	    expire_tv.tv_sec = 0;
	    expire_tv.tv_usec = 0;
	    FD_ZERO(&foofd);
	    FD_SET(cmd->fd, &foofd);
	    pollret = select(cmd->fd+1,
			 (SELECT_ARG_2_T) &foofd, NULL, NULL, &expire_tv);
#else
#ifdef FIONREAD
	    if (ioctl(cmd->fd, FIONREAD, (char *) &val) == 0)
		pollret = (val > 0);
#endif
#endif

	    if (pollret < 0) {
		/*
		 * See read_poll() for this.
		 * Last despairing effort to poll: attempt to
		 * set nonblocking I/O and actually read the
		 * character.  cmd->read stores the character read.
		 */
		long mode;

		if (setblock_fd(0, cmd->fd, &mode))
		    pollret = read(cmd->fd, &cmd->read, 1);
		if (mode != -1)
		    fcntl(cmd->fd, F_SETFL, mode);
	    }
	    if (pollret == 0)
		break;
	}
	if (!ret) {
	    checkptycmd(cmd);
	    if (cmd->fin)
		break;
	}
	if (cmd->read != -1 || (ret = read(cmd->fd, buf + used, 1)) == 1) {
	    if (cmd->read != -1) {
		ret = 1;
		buf[used] = (char) cmd->read;
		cmd->read = -1;
	    }
	    seen = 1;
	    if (++used == blen) {
		if (!*args) {
		    write_loop(1, buf, used);
		    used = 0;
		} else {
		    buf = hrealloc(buf, blen, blen << 1);
		    blen <<= 1;
		}
	    }
	}
	buf[used] = '\0';

	if (!prog) {
	    if (ret <= 0 || (*args && buf[used - 1] == '\n'))
		break;
	} else {
	    if (ret < 0
#ifdef EWOULDBLOCK
		&& errno != EWOULDBLOCK
#else
#ifdef EAGAIN
		&& errno != EAGAIN
#endif
#endif
		)
		break;
	}
    } while (!(errflag || breaks || retflag || contflag) &&
	     used < READ_MAX &&
	     !(prog && ret && (matchok = pattry(prog, buf))));

    if (prog && ret < 0 &&
#ifdef EWOULDBLOCK
	errno == EWOULDBLOCK
#else
#ifdef EAGAIN
	errno == EAGAIN
#endif
#endif
	) {
	cmd->old = (char *) zalloc(cmd->olen = used);
	memcpy(cmd->old, buf, cmd->olen);

	return 1;
    }
    if (*args)
	setsparam(*args, ztrdup(metafy(buf, used, META_HREALLOC)));
    else if (used)
	write_loop(1, buf, used);

    if (seen && (!prog || matchok || !mustmatch))
	return 0;
    return cmd->fin + 1;
}

static int
ptywritestr(Ptycmd cmd, char *s, int len)
{
    int written, all = 0;

    for (; !errflag && !breaks && !retflag && !contflag && len;
	 len -= written, s += written) {
	if ((written = write(cmd->fd, s, len)) < 0 && cmd->nblock &&
#ifdef EWOULDBLOCK
	    errno == EWOULDBLOCK
#else
#ifdef EAGAIN
	    errno == EAGAIN
#endif
#endif
	    )
	    return !all;
	if (written < 0) {
	    checkptycmd(cmd);
	    if (cmd->fin)
		break;
	    written = 0;
	}
	if (written > 0)
	    all += written;
    }
    return (all ? 0 : cmd->fin + 1);
}

static int
ptywrite(Ptycmd cmd, char **args, int nonl)
{
    if (*args) {
	char sp = ' ', *tmp;
	int len;

	while (*args) {
	    unmetafy((tmp = dupstring(*args)), &len);
	    if (ptywritestr(cmd, tmp, len) ||
		(*++args && ptywritestr(cmd, &sp, 1)))
		return 1;
	}
	if (!nonl) {
	    sp = '\n';
	    if (ptywritestr(cmd, &sp, 1))
		return 1;
	}
    } else {
	int n;
	char buf[BUFSIZ];

	while ((n = read(0, buf, BUFSIZ)) > 0)
	    if (ptywritestr(cmd, buf, n))
		return 1;
    }
    return 0;
}

/**/
static int
bin_zpty(char *nam, char **args, Options ops, UNUSED(int func))
{
    if ((OPT_ISSET(ops,'r') && OPT_ISSET(ops,'w')) ||
	((OPT_ISSET(ops,'r') || OPT_ISSET(ops,'w')) &&
	 (OPT_ISSET(ops,'d') || OPT_ISSET(ops,'e') ||
	  OPT_ISSET(ops,'b') || OPT_ISSET(ops,'L'))) ||
	(OPT_ISSET(ops,'w') && (OPT_ISSET(ops,'t') || OPT_ISSET(ops,'m'))) ||
	(OPT_ISSET(ops,'n') && (OPT_ISSET(ops,'b') || OPT_ISSET(ops,'e') ||
				OPT_ISSET(ops,'r') || OPT_ISSET(ops,'t') ||
				OPT_ISSET(ops,'d') || OPT_ISSET(ops,'L') ||
				OPT_ISSET(ops,'m'))) ||
	(OPT_ISSET(ops,'d') && (OPT_ISSET(ops,'b') || OPT_ISSET(ops,'e') ||
				OPT_ISSET(ops,'L') || OPT_ISSET(ops,'t') ||
				OPT_ISSET(ops,'m'))) ||
	(OPT_ISSET(ops,'L') && (OPT_ISSET(ops,'b') || OPT_ISSET(ops,'e') ||
				OPT_ISSET(ops,'m')))) {
	zwarnnam(nam, "illegal option combination");
	return 1;
    }
    if (OPT_ISSET(ops,'r') || OPT_ISSET(ops,'w')) {
	Ptycmd p;

	if (!*args) {
	    zwarnnam(nam, "missing pty command name");
	    return 1;
	} else if (!(p = getptycmd(*args))) {
	    zwarnnam(nam, "no such pty command: %s", *args);
	    return 1;
	}
	if (p->fin)
	    return 2;

	return (OPT_ISSET(ops,'r') ?
		ptyread(nam, p, args + 1, OPT_ISSET(ops,'t'),
			OPT_ISSET(ops, 'm')) :
		ptywrite(p, args + 1, OPT_ISSET(ops,'n')));
    } else if (OPT_ISSET(ops,'d')) {
	Ptycmd p;
	int ret = 0;

	if (*args) {
	    while (*args)
		if ((p = getptycmd(*args++)))
		    deleteptycmd(p);
		else {
		    zwarnnam(nam, "no such pty command: %s", args[-1]);
		    ret = 1;
		}
	} else
	    deleteallptycmds();

	return ret;
    } else if (OPT_ISSET(ops,'t')) {
	Ptycmd p;

	if (!*args) {
	    zwarnnam(nam, "missing pty command name");
	    return 1;
	} else if (!(p = getptycmd(*args))) {
	    zwarnnam(nam, "no such pty command: %s", *args);
	    return 1;
	}
	checkptycmd(p);
	return p->fin;
    } else if (*args) {
	if (!args[1]) {
	    zwarnnam(nam, "missing command");
	    return 1;
	}
	if (getptycmd(*args)) {
	    zwarnnam(nam, "pty command name already used: %s", *args);
	    return 1;
	}
	return newptycmd(nam, *args, args + 1, OPT_ISSET(ops,'e'), 
			 OPT_ISSET(ops,'b'));
    } else {
	Ptycmd p;
	char **a;

	for (p = ptycmds; p; p = p->next) {
	    checkptycmd(p);
	    if (OPT_ISSET(ops,'L'))
		printf("%s %s%s%s ", nam, (p->echo ? "-e " : ""),
		       (p->nblock ? "-b " : ""), p->name);
	    else if (p->fin)
		printf("(finished) %s: ", p->name);
	    else
		printf("(%d) %s: ", p->pid, p->name);
	    for (a = p->args; *a; ) {
		quotedzputs(*a++, stdout);
		if (*a)
		    putchar(' ');
	    }
	    putchar('\n');
	}
	return 0;
    }
}

static int
ptyhook(UNUSED(Hookdef d), UNUSED(void *dummy))
{
    deleteallptycmds();
    return 0;
}


static struct builtin bintab[] = {
    BUILTIN("zpty", 0, bin_zpty, 0, -1, 0, "ebdmrwLnt", NULL),
};

static struct features module_features = {
    bintab, sizeof(bintab)/sizeof(*bintab),
    NULL, 0,
    NULL, 0,
    NULL, 0,
    0
};


/**/
int
setup_(UNUSED(Module m))
{
    return 0;
}

/**/
int
features_(Module m, char ***features)
{
    *features = featuresarray(m, &module_features);
    return 0;
}

/**/
int
enables_(Module m, int **enables)
{
    return handlefeatures(m, &module_features, enables);
}

/**/
int
boot_(Module m)
{
    ptycmds = NULL;

    addhookfunc("exit", ptyhook);
    return 0;
}

/**/
int
cleanup_(Module m)
{
    deletehookfunc("exit", ptyhook);
    deleteallptycmds();
    return setfeatureenables(m, &module_features, NULL);
}

/**/
int
finish_(UNUSED(Module m))
{
    return 0;
}
