/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * 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 <zircon/process.h>
#include <zircon/processargs.h>
#include <zircon/syscalls.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

#include "shell.h"
#include "main.h"
#include "options.h"
#include "output.h"
#include "parser.h"
#include "nodes.h"
#include "expand.h"
#include "eval.h"
#include "jobs.h"
#include "input.h"
#include "trap.h"
#include "var.h"
#include "show.h"
#include "memalloc.h"
#include "error.h"
#include "init.h"
#include "mystring.h"
#include "exec.h"
#include "cd.h"

#define PROFILE 0

int rootpid;
int shlvl;
#ifdef __GLIBC__
int *dash_errno;
#endif
#if PROFILE
short profile_buf[16384];
extern int etext();
#endif

STATIC void read_profile(const char *);
STATIC char *find_dot_file(char *);
STATIC void evalifsubshell(zx_handle_t);
static int cmdloop(int);
int main(int, char **);

/*
 * Main routine.  We initialize things, parse the arguments, execute
 * profiles if we're a login shell, and then call cmdloop to execute
 * commands.  The setjmp call sets up the location to jump to when an
 * exception occurs.  When an exception occurs the variable "state"
 * is used to figure out how far we had gotten.
 */

int
main(int argc, char **argv)
{
	char *shinit;
	volatile int state;
	struct jmploc jmploc;
	struct stackmark smark;
	int login;

#ifdef __GLIBC__
	dash_errno = __errno_location();
#endif

#if PROFILE
	monitor(4, etext, profile_buf, sizeof profile_buf, 50);
#endif
	state = 0;
	if (unlikely(setjmp(jmploc.loc))) {
		int e;
		int s;

		reset();

		e = exception;

		s = state;
		if (e == EXEXIT || s == 0 || iflag == 0 || shlvl)
			exitshell();

		if (e == EXINT
#if ATTY
		 && (! attyset() || equal(termval(), "emacs"))
#endif
		 ) {
			out2c('\n');
#ifdef FLUSHERR
			flushout(out2);
#endif
		}
		popstackmark(&smark);
		FORCEINTON;				/* enable interrupts */
		if (s == 1)
			goto state1;
		else if (s == 2)
			goto state2;
		else if (s == 3)
			goto state3;
		else
			goto state4;
	}
	handler = &jmploc;
#ifdef DEBUG
	opentrace();
	trputs("Shell args:  ");  trargs(argv);
#endif
	rootpid = getpid();
	init();
	setstackmark(&smark);

	zx_handle_t ast_vmo = zx_get_startup_handle(PA_HND(PA_USER0, 0));

	login = procargs(argc, argv, ast_vmo != ZX_HANDLE_INVALID);

        // Fuchsia: recognize if we have been invoked for the purpose of evaluating
	// an expression (i.e., node) and exiting immediately.
	evalifsubshell(ast_vmo);

	if (login) {
		state = 1;
		read_profile("/etc/profile");
state1:
		state = 2;
		read_profile("$HOME/.profile");
	}
	settitle("sh");
state2:
	state = 3;
	if (
#ifndef linux
		getuid() == geteuid() && getgid() == getegid() &&
#endif
		iflag
	) {
		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
			read_profile(shinit);
		}
	}
	popstackmark(&smark);
state3:
	state = 4;
	if (minusc)
		evalstring(minusc, sflag ? 0 : EV_EXIT);

	if (sflag || minusc == NULL) {
state4:	/* XXX ??? - why isn't this before the "if" statement */
		cmdloop(1);
	}
#if PROFILE
	monitor(0);
#endif
#if GPROF
	{
		extern void _mcleanup(void);
		_mcleanup();
	}
#endif
	exitshell();
	/* NOTREACHED */
}

STATIC void
evalifsubshell(zx_handle_t ast_vmo)
{
	if (ast_vmo == ZX_HANDLE_INVALID)
		return;

	uint64_t size;
	zx_status_t status = zx_vmo_get_size(ast_vmo, &size);
	if (status != ZX_OK)
		exit(status);

	char buffer[size];

	size_t num_read;
	status = zx_vmo_read_old(ast_vmo, buffer, 0, size, &num_read);
	if (status < 0 || (size_t)num_read != size)
		exit(status);

	struct nodelist *nlist = codec_decode(buffer, size);
	if (nlist == NULL) {
		return;
	}
	while (nlist->next) {
		evaltree(nlist->n, 0);
		nlist = nlist->next;
	}
	evaltree(nlist->n, EV_EXIT);
	/* NOTREACHED */
}


/*
 * Read and execute commands.  "Top" is nonzero for the top level command
 * loop; it turns on prompting if the shell is interactive.
 */

static int
cmdloop(int top)
{
	union node *n;
	struct stackmark smark;
	int inter;
	int status = 0;
	int numeof = 0;

	TRACE(("cmdloop(%d) called\n", top));
	for (;;) {
		int skip;

		setstackmark(&smark);
		if (jobctl)
			showjobs(out2, SHOW_CHANGED);
		inter = 0;
		if (iflag && top)
			inter++;
		n = parsecmd(inter);
		/* showtree(n); DEBUG */
		if (n == NEOF) {
			if (!top || numeof >= 50)
				break;
			if (!stoppedjobs()) {
				if (!Iflag)
					break;
				out2str("\nUse \"exit\" to leave shell.\n");
			}
			numeof++;
		} else if (nflag == 0) {
			int i;

			job_warning = (job_warning == 2) ? 1 : 0;
			numeof = 0;
			i = evaltree(n, 0);
			if (n)
				status = i;
		}
		popstackmark(&smark);

		skip = evalskip;
		if (skip) {
			evalskip &= ~(SKIPFUNC | SKIPFUNCDEF);
			break;
		}
	}

	return status;
}


/*
 * Read /etc/profile or .profile.  Return on error.
 */

STATIC void
read_profile(const char *name)
{
	name = expandstr(name);
	if (setinputfile(name, INPUT_PUSH_FILE | INPUT_NOFILE_OK) < 0)
		return;

	cmdloop(0);
	popfile();
}


/*
 * Read a file containing shell functions.
 */

void
readcmdfile(char *name)
{
	setinputfile(name, INPUT_PUSH_FILE);
	cmdloop(0);
	popfile();
}


/*
 * Take commands from a file.  To be compatible we should do a path
 * search for the file, which is necessary to find sub-commands.
 */


STATIC char *
find_dot_file(char *basename)
{
	char *fullname;
	const char *path = pathval();
	struct stat statb;

	/* don't try this for absolute or relative paths */
	if (strchr(basename, '/'))
		return basename;

	while ((fullname = padvance(&path, basename)) != NULL) {
		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
			/*
			 * Don't bother freeing here, since it will
			 * be freed by the caller.
			 */
			return fullname;
		}
		stunalloc(fullname);
	}

	/* not found in the PATH */
	sh_error("%s: not found", basename);
	/* NOTREACHED */
}

int
dotcmd(int argc, char **argv)
{
	int status = 0;

	nextopt(nullstr);
	argv = argptr;

	if (*argv) {
		char *fullname;

		fullname = find_dot_file(*argv);
		setinputfile(fullname, INPUT_PUSH_FILE);
		commandname = fullname;
		status = cmdloop(0);
		popfile();
	}

	return status;
}


int
exitcmd(int argc, char **argv)
{
	if (stoppedjobs())
		return 0;

	if (argc > 1) {
		int status = number(argv[1]);

		exitstatus = status;
		if (savestatus >= 0)
			savestatus = status;
	}

	exraise(EXEXIT);
	/* NOTREACHED */
}