escape.c

unix环境高级编程的源代码

#include    "call.h"
#include    <signal.h>

/* Called when first character of a line is the escape character
 * (tilde).  Read the next character and process.  Return -1
 * if next character is "terminate" charcter, 0 if next character
 * is valid command character (that's been processed), or next
 * character itself (if the next character is not special). */

int
doescape(int remfd)
{
    char    c;

    if (read(STDIN_FILENO, &c, 1) != 1)        /* next input char */
        err_sys("read error from stdin");

    if (c == escapec)        /* two in a row -> process as one */
        return(escapec);

    else if (c == '.') {    /* terminate */
        write(STDOUT_FILENO, "~.\n\r", 4);
        return(-1);

#ifdef    VSUSP
    } else if (c == tty_termios()->c_cc[VSUSP]) { /* suspend client */
        tty_cbreak(STDIN_FILENO);    /* restore tty mode */
        kill(getpid(), SIGTSTP);    /* suspend ourself */

        tty_raw(STDIN_FILENO);        /* and reset tty to raw */
        return(0);
#endif

    } else if (c == '#') {    /* generate break */
        tcsendbreak(remfd, 0);
        return(0);

    } else if (c == 't') {    /* take a file from remote host */
        take(remfd);
        return(0);

    } else if (c == 'p') {    /* put a file to remote host */
        put(remfd);
        return(0);
    }

    return(c);            /* not a special character */
}