execute.c

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/*
 *	(c) Copyright 1990, Kim Fabricius Storm.  All rights reserved.
 *
 *	UNIX command execution.
 */

#include <signal.h>
#include <errno.h>
#include "config.h"
#include "term.h"

export int shell_restrictions = 0;	/* disable shell escapes */

export char *init_shell = SHELL;
export char *user_shell;
export char *exec_chdir_to = NULL;

static shell_check()
{
    if (shell_restrictions) {
	msg("Restricted operation - not allowed");
	return -1;
    }
    return 0;
}


init_execute()
{
    if ((user_shell = getenv("SHELL")) == NULL)
	user_shell = SHELL;
}

execute(path, args, toggle_visual)
char *path, **args;
int toggle_visual;
{
    int was_raw, pid, i, status;
    sig_type  (*quit)(), (*intr)(), (*tstp)();
    extern int errno;

    was_raw = toggle_visual ? visual_off() : unset_raw();

    while ((pid = fork()) == -1) sleep(1);

    if (pid == 0) {
	for (i = 3 ; i < 20 ; i++)
	    close(i);

	if (exec_chdir_to != NULL) chdir(exec_chdir_to);

	execv(path, args);

	fprintf(stderr, "%s: not found\n", path);
	nn_exit(20);
    }
    quit = signal(SIGQUIT, SIG_IGN);
    intr = signal(SIGINT,  SIG_IGN);
#ifdef HAVE_JOBCONTROL
    tstp = signal(SIGTSTP, SIG_DFL);
#endif
    while ((i = wait(&status)) != pid && (i != -1 || errno == EINTR));

    signal(SIGQUIT, quit);
    signal(SIGINT,  intr);
#ifdef HAVE_JOBCONTROL
    signal(SIGTSTP, tstp);
#endif
    if (toggle_visual) {
	visual_on();
	if (toggle_visual == 2) s_redraw++;
    }

    if (was_raw) raw();

    return (status & 0xff) ? 0x100 : (status >> 8);
}


shell_escape()
{
    static char command[FILENAME] = "";
    char *cmd;
    int first = 1;

    if (shell_check()) return 0;

    for (;;) {
	prompt("\1!\1");
	cmd = get_s(command, NONE, NONE, NULL_FCT);
	if (cmd == NULL) return !first;

	if (*cmd == NUL) {
	    if (first) run_shell((char *)NULL, 1, 0);
	    return 1;
	}

	strcpy(command, cmd);

	if (run_shell(command, first, 0) < 0) return !first;
	first = 0;
	prompt_line = -1;
    }
}


static char *exec_sh_args[] = {
    "nnsh",
    (char *)NULL, /* "-c" or "-i" */
    (char *)NULL, /* cmdstring */
    (char *)NULL
};

run_shell(command, clear, init_sh)
char *command;
int clear; /* -2 => no command output (:!!command) - keep visual,
	      output before command: -1 => none, 0 => CR/NL, 1 => clear */
int init_sh;	/* 0 => use user_shell, else use init_shell */
{
    char cmdstring[512];

    if (shell_check()) return -1;

    if (command != NULL) {
	if (!expand_file_name(cmdstring, command, 1)) return -1;
	exec_sh_args[1] = "-c";
        exec_sh_args[2] = cmdstring;
    } else {
	exec_sh_args[1] = "-i";
        exec_sh_args[2] = NULL;
    }

    if (clear > 0) {
	clrdisp();
	fl;
    } else if (clear == 0) {
	putchar(CR);
	putchar(NL);
    }

    return execute(init_sh ? init_shell : user_shell,
		   exec_sh_args, clear == -2 ? 0 : 1);
}

#ifndef HAVE_JOBCONTROL
static char *exec_suspend_args[] = {
    "nnsh",
    "-i",
    (char *)NULL
};
#endif

suspend_nn()
{
    int was_raw;

    if (shell_check()) return 0;

    gotoxy(0, Lines-1);
    clrline();

#ifdef HAVE_JOBCONTROL
    was_raw = visual_off();
    kill(process_id, SIGSTOP);
    visual_on();
    s_redraw++;
    if (was_raw) raw();
#else
    execute(user_shell, exec_suspend_args, 2);
#endif

    return 1;
}
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