sendmail/libsm/fclose.c

/*
 * Copyright (c) 2000-2002, 2004 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: fclose.c,v 1.44 2005/06/14 23:07:20 ca Exp $")
#include <errno.h>
#include <stdlib.h>
#include <sm/time.h>
#include <setjmp.h>
#include <sm/io.h>
#include <sm/assert.h>
#include <sm/heap.h>
#include <sm/signal.h>
#include <sm/conf.h>
#include <sm/clock.h>
#include "local.h"

static void closealrm __P((int));
static jmp_buf CloseTimeOut;

/*
**  CLOSEALRM -- handler when timeout activated for sm_io_close()
**
**  Returns flow of control to where setjmp(CloseTimeOut) was set.
**
**  Parameters:
**      sig -- unused
**
**  Returns:
**      does not return
**
**  Side Effects:
**      returns flow of control to setjmp(CloseTimeOut).
**
**  NOTE:   THIS CAN BE CALLED FROM A SIGNAL HANDLER.  DO NOT ADD
**      ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
**      DOING.
*/

/* ARGSUSED0 */
static void
closealrm(sig)
    int sig;
{
    longjmp(CloseTimeOut, 1);
}

/*
**  SM_IO_CLOSE -- close a file handle/pointer
**
**  Parameters:
**      fp -- file pointer to be closed
**      timeout -- maximum time allowed to perform the close (millisecs)
**
**  Returns:
**      0 on success
**      -1 on failure and sets errno
**
**  Side Effects:
**      file pointer 'fp' will no longer be valid.
*/

int
sm_io_close(fp, timeout)
    register SM_FILE_T *fp;
    int SM_NONVOLATILE timeout;
{
    register int SM_NONVOLATILE r;
    SM_EVENT *evt = NULL;

    if (fp == NULL)
    {
        errno = EBADF;
        return SM_IO_EOF;
    }

    SM_REQUIRE_ISA(fp, SmFileMagic);

    /* XXX this won't be reached if above macro is active */
    if (fp->sm_magic == NULL)
    {
        /* not open! */
        errno = EBADF;
        return SM_IO_EOF;
    }
    if (fp->f_close == NULL)
    {
        /* no close function! */
        errno = ENODEV;
        return SM_IO_EOF;
    }
    if (fp->f_dup_cnt > 0)
    {
        /* decrement file pointer open count */
        fp->f_dup_cnt--;
        return 0;
    }

    /*  Okay, this is where we set the timeout.  */
    if (timeout == SM_TIME_DEFAULT)
        timeout = fp->f_timeout;
    if (timeout == SM_TIME_IMMEDIATE)
    {
        errno = EAGAIN;
        return -1;
    }

    /* No more duplicates of file pointer. Flush buffer and close */
    r = fp->f_flags & SMWR ? sm_flush(fp, (int *) &timeout) : 0;

    /* sm_flush() has updated to.it_value for the time it's used */
    if (timeout != SM_TIME_FOREVER)
    {
        if (setjmp(CloseTimeOut) != 0)
        {
            errno = EAGAIN;
            return SM_IO_EOF;
        }
        evt = sm_seteventm(timeout, closealrm, 0);
    }
    if ((*fp->f_close)(fp) < 0)
        r = SM_IO_EOF;

    /*  We're back. So undo our timeout and handler */
    if (evt != NULL)
        sm_clrevent(evt);
    if (fp->f_flags & SMMBF)
    {
        sm_free((char *)fp->f_bf.smb_base);
        fp->f_bf.smb_base = NULL;
    }
    if (HASUB(fp))
        FREEUB(fp);
    fp->f_flags = 0;    /* clear flags */
    fp->sm_magic = NULL;    /* Release this SM_FILE_T for reuse. */
    fp->f_r = fp->f_w = 0;  /* Mess up if reaccessed. */
    return r;
}