com_shell.c

来自「ngspice又一个电子CAD仿真软件代码.功能更全」· C语言 代码 · 共 64 行

/*************
* com_shell.c
* $Id: com_shell.c,v 1.2 2005/05/30 20:28:30 sjborley Exp $
************/

#include <config.h>
#include <ngspice.h>
#include <wordlist.h>

#include "com_shell.h"


/* Fork a shell. */

void
com_shell(wordlist *wl)
{
    char *com, *shell = NULL;

    shell = getenv("SHELL");
    if (shell == NULL)
        shell = "/bin/csh";

        cp_ccon(FALSE);

#ifdef HAVE_VFORK_H
	/* XXX Needs to switch process groups.  Also, worry about suspend */
	/* Only bother for efficiency */
        pid = vfork();
        if (pid == 0) {
            fixdescriptors();
	    if (wl == NULL) {
		execl(shell, shell, 0);
		_exit(99);
	    } else {
		com = wl_flatten(wl);
		execl("/bin/sh", "sh", "-c", com, 0);
	    }
        } else {
	    /* XXX Better have all these signals */
	    svint = signal(SIGINT, SIG_DFL);
	    svquit = signal(SIGQUIT, SIG_DFL);
	    svtstp = signal(SIGTSTP, SIG_DFL);
	    /* XXX Sig on proc group */
            do {
                r = wait((union wait *) NULL);
            } while ((r != pid) && pid != -1);
	    signal(SIGINT, (SIGNAL_FUNCTION) svint);
	    signal(SIGQUIT, (SIGNAL_FUNCTION) svquit);
	    signal(SIGTSTP, (SIGNAL_FUNCTION) svtstp);
        }
#else
    /* Easier to forget about changing the io descriptors. */
    if (wl) {
        com = wl_flatten(wl);
        system(com);
    } else
        system(shell);
#endif

    return;
}