/*
 * error.c -- main error handling routines
 *
 * This code is Copyright (c) 2002, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

#include <h/mh.h>

#include <sys/types.h>
#include <sys/uio.h>


/*
 * print out error message
 */
void
advise (char *what, char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    advertise (what, NULL, fmt, ap);
    va_end(ap);
}


/*
 * print out error message and exit
 */
void
adios (char *what, char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    advertise (what, NULL, fmt, ap);
    va_end(ap);
    done (1);
}


/*
 * admonish the user
 */
void
admonish (char *what, char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    advertise (what, "continuing...", fmt, ap);
    va_end(ap);
}


/*
 * main routine for printing error messages.
 */
void
advertise (char *what, char *tail, char *fmt, va_list ap)
{
    int	eindex = errno;
    char buffer[BUFSIZ], err[BUFSIZ];
    struct iovec iob[20], *iov;

    fflush (stdout);

    fflush (stderr);
    iov = iob;

    if (invo_name && *invo_name) {
	iov->iov_len = strlen (iov->iov_base = invo_name);
	iov++;
	iov->iov_len = strlen (iov->iov_base = ": ");
	iov++;
    }
    
    vsnprintf (buffer, sizeof(buffer), fmt, ap);
    iov->iov_len = strlen (iov->iov_base = buffer);
    iov++;
    if (what) {
	if (*what) {
	    iov->iov_len = strlen (iov->iov_base = " ");
	    iov++;
	    iov->iov_len = strlen (iov->iov_base = what);
	    iov++;
	    iov->iov_len = strlen (iov->iov_base = ": ");
	    iov++;
	}
        if (!(iov->iov_base = strerror (eindex))) {
	    /* this shouldn't happen, but we'll test for it just in case */
	    snprintf (err, sizeof(err), "Error %d", eindex);
	    iov->iov_base = err;
	}
	iov->iov_len = strlen (iov->iov_base);
	iov++;
    }
    if (tail && *tail) {
	iov->iov_len = strlen (iov->iov_base = ", ");
	iov++;
	iov->iov_len = strlen (iov->iov_base = tail);
	iov++;
    }
    iov->iov_len = strlen (iov->iov_base = "\n");
    iov++;
    if (writev (fileno (stderr), iob, iov - iob) < 0) {
	advise ("stderr", "writev");
    }
}