OpenSolaris_b135/cmd/sendmail/libsm/refill.c
/*
* Copyright (c) 2000-2001, 2005-2006 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: refill.c,v 1.53 2006/02/28 18:48:25 ca Exp $")
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <sm/time.h>
#include <fcntl.h>
#include <string.h>
#include <sm/io.h>
#include <sm/conf.h>
#include <sm/assert.h>
#include "local.h"
static int sm_lflush __P((SM_FILE_T *, int *));
/*
** SM_IO_RD_TIMEOUT -- measured timeout for reads
**
** This #define uses a select() to wait for the 'fd' to become readable.
** The select() can be active for up to 'To' time. The select() may not
** use all of the the 'To' time. Hence, the amount of "wall-clock" time is
** measured to decide how much to subtract from 'To' to update it. On some
** BSD-based/like systems the timeout for a select() is updated for the
** amount of time used. On many/most systems this does not happen. Therefore
** the updating of 'To' must be done ourselves; a copy of 'To' is passed
** since a BSD-like system will have updated it and we don't want to
** double the time used!
** Note: if a valid 'fd' doesn't exist yet, don't use this (e.g. the
** sendmail buffered file type in sendmail/bf.c; see use below).
**
** Parameters
** fp -- the file pointer for the active file
** fd -- raw file descriptor (from 'fp') to use for select()
** to -- struct timeval of the timeout
** timeout -- the original timeout value
** sel_ret -- the return value from the select()
**
** Returns:
** nothing, flow through code
*/
#define SM_IO_RD_TIMEOUT(fp, fd, to, timeout, sel_ret) \
{ \
struct timeval sm_io_to_before, sm_io_to_after, sm_io_to_diff; \
fd_set sm_io_to_mask, sm_io_x_mask; \
errno = 0; \
if (timeout == SM_TIME_IMMEDIATE) \
{ \
errno = EAGAIN; \
return SM_IO_EOF; \
} \
if (FD_SETSIZE > 0 && (fd) >= FD_SETSIZE) \
{ \
errno = EINVAL; \
return SM_IO_EOF; \
} \
FD_ZERO(&sm_io_to_mask); \
FD_SET((fd), &sm_io_to_mask); \
FD_ZERO(&sm_io_x_mask); \
FD_SET((fd), &sm_io_x_mask); \
if (gettimeofday(&sm_io_to_before, NULL) < 0) \
return SM_IO_EOF; \
do \
{ \
(sel_ret) = select((fd) + 1, &sm_io_to_mask, NULL, \
&sm_io_x_mask, (to)); \
} while ((sel_ret) < 0 && errno == EINTR); \
if ((sel_ret) < 0) \
{ \
/* something went wrong, errno set */ \
fp->f_r = 0; \
fp->f_flags |= SMERR; \
return SM_IO_EOF; \
} \
else if ((sel_ret) == 0) \
{ \
/* timeout */ \
errno = EAGAIN; \
return SM_IO_EOF; \
} \
/* calulate wall-clock time used */ \
if (gettimeofday(&sm_io_to_after, NULL) < 0) \
return SM_IO_EOF; \
timersub(&sm_io_to_after, &sm_io_to_before, &sm_io_to_diff); \
timersub((to), &sm_io_to_diff, (to)); \
}
/*
** SM_LFLUSH -- flush a file if it is line buffered and writable
**
** Parameters:
** fp -- file pointer to flush
** timeout -- original timeout value (in milliseconds)
**
** Returns:
** Failure: returns SM_IO_EOF and sets errno
** Success: returns 0
*/
static int
sm_lflush(fp, timeout)
SM_FILE_T *fp;
int *timeout;
{
if ((fp->f_flags & (SMLBF|SMWR)) == (SMLBF|SMWR))
return sm_flush(fp, timeout);
return 0;
}
/*
** SM_REFILL -- refill a buffer
**
** Parameters:
** fp -- file pointer for buffer refill
** timeout -- time to complete filling the buffer in milliseconds
**
** Returns:
** Success: returns 0
** Failure: returns SM_IO_EOF
*/
int
sm_refill(fp, timeout)
register SM_FILE_T *fp;
int timeout;
{
int ret, r;
struct timeval to;
int fd;
if (timeout == SM_TIME_DEFAULT)
timeout = fp->f_timeout;
if (timeout == SM_TIME_IMMEDIATE)
{
/*
** Filling the buffer will take time and we are wanted to
** return immediately. And we're not EOF or ERR really.
** So... the failure is we couldn't do it in time.
*/
errno = EAGAIN;
fp->f_r = 0; /* just to be sure */
return 0;
}
/* make sure stdio is set up */
if (!Sm_IO_DidInit)
sm_init();
fp->f_r = 0; /* largely a convenience for callers */
if (fp->f_flags & SMFEOF)
return SM_IO_EOF;
SM_CONVERT_TIME(fp, fd, timeout, &to);
/* if not already reading, have to be reading and writing */
if ((fp->f_flags & SMRD) == 0)
{
if ((fp->f_flags & SMRW) == 0)
{
errno = EBADF;
fp->f_flags |= SMERR;
return SM_IO_EOF;
}
/* switch to reading */
if (fp->f_flags & SMWR)
{
if (sm_flush(fp, &timeout))
return SM_IO_EOF;
fp->f_flags &= ~SMWR;
fp->f_w = 0;
fp->f_lbfsize = 0;
}
fp->f_flags |= SMRD;
}
else
{
/*
** We were reading. If there is an ungetc buffer,
** we must have been reading from that. Drop it,
** restoring the previous buffer (if any). If there
** is anything in that buffer, return.
*/
if (HASUB(fp))
{
FREEUB(fp);
if ((fp->f_r = fp->f_ur) != 0)
{
fp->f_p = fp->f_up;
/* revert blocking state */
return 0;
}
}
}
if (fp->f_bf.smb_base == NULL)
sm_makebuf(fp);
/*
** Before reading from a line buffered or unbuffered file,
** flush all line buffered output files, per the ANSI C standard.
*/
if (fp->f_flags & (SMLBF|SMNBF))
(void) sm_fwalk(sm_lflush, &timeout);
/*
** If this file is linked to another, and we are going to hang
** on the read, flush the linked file before continuing.
*/
if (fp->f_flushfp != NULL &&
(*fp->f_getinfo)(fp, SM_IO_IS_READABLE, NULL) <= 0)
sm_flush(fp->f_flushfp, &timeout);
fp->f_p = fp->f_bf.smb_base;
/*
** The do-while loop stops trying to read when something is read
** or it appears that the timeout has expired before finding
** something available to be read (via select()).
*/
ret = 0;
do
{
errno = 0; /* needed to ensure EOF correctly found */
r = (*fp->f_read)(fp, (char *)fp->f_p, fp->f_bf.smb_size);
if (r <= 0)
{
if (r == 0 && errno == 0)
break; /* EOF found */
if (IS_IO_ERROR(fd, r, timeout))
goto err; /* errno set */
/* read would block */
SM_IO_RD_TIMEOUT(fp, fd, &to, timeout, ret);
}
} while (r <= 0 && ret > 0);
err:
if (r <= 0)
{
if (r == 0)
fp->f_flags |= SMFEOF;
else
fp->f_flags |= SMERR;
fp->f_r = 0;
return SM_IO_EOF;
}
fp->f_r = r;
return 0;
}
/*
** SM_RGET -- refills buffer and returns first character
**
** Handle sm_getc() when the buffer ran out:
** Refill, then return the first character in the newly-filled buffer.
**
** Parameters:
** fp -- file pointer to work on
** timeout -- time to complete refill
**
** Returns:
** Success: first character in refilled buffer as an int
** Failure: SM_IO_EOF
*/
int
sm_rget(fp, timeout)
register SM_FILE_T *fp;
int timeout;
{
if (sm_refill(fp, timeout) == 0)
{
fp->f_r--;
return *fp->f_p++;
}
return SM_IO_EOF;
}