com_err.c

/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * Copyright 1997 by Massachusetts Institute of Technology
 *
 * Copyright 1987, 1988 by MIT Student Information Processing Board
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for any purpose and without fee is
 * hereby granted, provided that the above copyright notice
 * appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation,
 * and that the names of M.I.T. and the M.I.T. S.I.P.B. not be
 * used in advertising or publicity pertaining to distribution
 * of the software without specific, written prior permission.
 * Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. and the M.I.T. S.I.P.B. make no representations about
 * the suitability of this software for any purpose.  It is
 * provided "as is" without express or implied warranty.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "com_err.h"
#include "error_table.h"

#if defined(_WIN32)
#include <io.h>
#endif

static /*@null@*/ et_old_error_hook_func com_err_hook = 0;
k5_mutex_t com_err_hook_lock = K5_MUTEX_PARTIAL_INITIALIZER;

#if defined(_WIN32)
BOOL  isGuiApp(void) {
    DWORD mypid;
    HANDLE myprocess;
    mypid = GetCurrentProcessId();
    myprocess = OpenProcess( PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, mypid);
    return GetGuiResources(myprocess, 1) > 0;
}
#endif

static void default_com_err_proc (const char *whoami, errcode_t code,
                                  const char *fmt, va_list ap)
{
#if defined(_WIN32)

    char errbuf[1024] = "";

    if (whoami) {
        errbuf[sizeof(errbuf) - 1] = '\0';
        strncat (errbuf, whoami, sizeof(errbuf) - 1 - strlen(errbuf));
        strncat (errbuf, ": ", sizeof(errbuf) - 1 - strlen(errbuf));
    }
    if (code) {
        errbuf[sizeof(errbuf) - 1] = '\0';
        strncat (errbuf, error_message(code), sizeof(errbuf) - 1 - strlen(errbuf));
        strncat (errbuf, " ", sizeof(errbuf) - 1 - strlen(errbuf));
    }
    if (fmt)
        /* ITS4: ignore vsprintf */
        vsprintf (errbuf + strlen (errbuf), fmt, ap);
    errbuf[sizeof(errbuf) - 1] = '\0';

    if (_isatty(_fileno(stderr)) || !isGuiApp()) {
        fputs(errbuf, stderr);
        fputc('\r', stderr);
        fputc('\n', stderr);
        fflush(stderr);
    } else
        MessageBox ((HWND)NULL, errbuf, "Kerberos", MB_ICONEXCLAMATION);

#else /* !_WIN32 */

    if (whoami) {
        fputs(whoami, stderr);
        fputs(": ", stderr);
    }
    if (code) {
        fputs(error_message(code), stderr);
        fputs(" ", stderr);
    }
    if (fmt) {
        vfprintf(stderr, fmt, ap);
    }
    /* should do this only on a tty in raw mode */
    putc('\r', stderr);
    putc('\n', stderr);
    fflush(stderr);

#endif
}

void KRB5_CALLCONV com_err_va(const char *whoami,
                              errcode_t code,
                              const char *fmt,
                              va_list ap)
{
    int err;
    et_old_error_hook_func p;

    err = com_err_finish_init();
    if (err)
        goto best_try;
    k5_mutex_lock(&com_err_hook_lock);
    p = com_err_hook ? com_err_hook : default_com_err_proc;
    (*p)(whoami, code, fmt, ap);
    k5_mutex_unlock(&com_err_hook_lock);
    return;

best_try:
    /* Yikes.  Our library initialization failed or we couldn't lock
       the lock we want.  We could be in trouble.  Gosh, we should
       probably print an error message.  Oh, wait.  That's what we're
       trying to do.  In fact, if we're losing on initialization here,
       there's a good chance it has to do with failed initialization
       of the caller.  */
    if (!com_err_hook)
        default_com_err_proc(whoami, code, fmt, ap);
    else
        (com_err_hook)(whoami, code, fmt, ap);
    assert(err == 0);
    abort();
}


void KRB5_CALLCONV_C com_err(const char *whoami,
                             errcode_t code,
                             const char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    com_err_va(whoami, code, fmt, ap);
    va_end(ap);
}

/* Make a separate function because the assert invocations below
   use the macro expansion on some platforms, which may be insanely
   long and incomprehensible.  */
static void com_err_lock_hook_handle(void)
{
    k5_mutex_lock(&com_err_hook_lock);
}

et_old_error_hook_func set_com_err_hook (et_old_error_hook_func new_proc)
{
    et_old_error_hook_func x;

    /* Broken initialization?  What can we do?  */
    if (com_err_finish_init() != 0)
        abort();
    com_err_lock_hook_handle();
    x = com_err_hook;
    com_err_hook = new_proc;
    k5_mutex_unlock(&com_err_hook_lock);
    return x;
}

et_old_error_hook_func reset_com_err_hook (void)
{
    et_old_error_hook_func x;

    /* Broken initialization?  What can we do?  */
    if (com_err_finish_init() != 0)
        abort();
    com_err_lock_hook_handle();
    x = com_err_hook;
    com_err_hook = NULL;
    k5_mutex_unlock(&com_err_hook_lock);
    return x;
}