ef9770707c
Security: FreeBSD-SA-06:13.sendmail
182 lines
3.9 KiB
C
182 lines
3.9 KiB
C
/*
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* Copyright (c) 2000-2001, 2004 Sendmail, Inc. and its suppliers.
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* All rights reserved.
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*/
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#include <sm/gen.h>
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SM_IDSTR(id, "@(#)$Id: ungetc.c,v 1.30 2005/06/14 23:07:20 ca Exp $")
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include <sm/time.h>
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#include <errno.h>
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#include <sm/io.h>
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#include <sm/heap.h>
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#include <sm/assert.h>
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#include <sm/conf.h>
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#include "local.h"
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static void sm_submore_x __P((SM_FILE_T *));
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/*
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** SM_SUBMORE_X -- expand ungetc buffer
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**
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** Expand the ungetc buffer `in place'. That is, adjust fp->f_p when
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** the buffer moves, so that it points the same distance from the end,
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** and move the bytes in the buffer around as necessary so that they
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** are all at the end (stack-style).
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**
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** Parameters:
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** fp -- the file pointer
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**
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** Results:
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** none.
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**
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** Exceptions:
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** F:sm_heap -- out of memory
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*/
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static void
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sm_submore_x(fp)
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SM_FILE_T *fp;
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{
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register int i;
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register unsigned char *p;
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if (fp->f_ub.smb_base == fp->f_ubuf)
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{
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/* Get a buffer; f_ubuf is fixed size. */
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p = sm_malloc_x((size_t) SM_IO_BUFSIZ);
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fp->f_ub.smb_base = p;
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fp->f_ub.smb_size = SM_IO_BUFSIZ;
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p += SM_IO_BUFSIZ - sizeof(fp->f_ubuf);
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for (i = sizeof(fp->f_ubuf); --i >= 0;)
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p[i] = fp->f_ubuf[i];
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fp->f_p = p;
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return;
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}
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i = fp->f_ub.smb_size;
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p = sm_realloc_x(fp->f_ub.smb_base, i << 1);
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/* no overlap (hence can use memcpy) because we doubled the size */
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(void) memcpy((void *) (p + i), (void *) p, (size_t) i);
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fp->f_p = p + i;
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fp->f_ub.smb_base = p;
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fp->f_ub.smb_size = i << 1;
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}
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/*
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** SM_IO_UNGETC -- place a character back into the buffer just read
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**
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** Parameters:
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** fp -- the file pointer affected
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** timeout -- time to complete ungetc
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** c -- the character to place back
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**
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** Results:
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** On success, returns value of character placed back, 0-255.
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** Returns SM_IO_EOF if c == SM_IO_EOF or if last operation
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** was a write and flush failed.
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**
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** Exceptions:
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** F:sm_heap -- out of memory
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*/
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int
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sm_io_ungetc(fp, timeout, c)
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register SM_FILE_T *fp;
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int timeout;
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int c;
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{
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SM_REQUIRE_ISA(fp, SmFileMagic);
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if (c == SM_IO_EOF)
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return SM_IO_EOF;
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if (timeout == SM_TIME_IMMEDIATE)
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{
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/*
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** Ungetting the buffer will take time and we are wanted to
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** return immediately. So...
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*/
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errno = EAGAIN;
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return SM_IO_EOF;
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}
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if (!Sm_IO_DidInit)
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sm_init();
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if ((fp->f_flags & SMRD) == 0)
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{
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/*
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** Not already reading: no good unless reading-and-writing.
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** Otherwise, flush any current write stuff.
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*/
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if ((fp->f_flags & SMRW) == 0)
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return SM_IO_EOF;
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if (fp->f_flags & SMWR)
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{
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if (sm_flush(fp, &timeout))
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return SM_IO_EOF;
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fp->f_flags &= ~SMWR;
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fp->f_w = 0;
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fp->f_lbfsize = 0;
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}
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fp->f_flags |= SMRD;
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}
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c = (unsigned char) c;
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/*
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** If we are in the middle of ungetc'ing, just continue.
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** This may require expanding the current ungetc buffer.
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*/
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if (HASUB(fp))
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{
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if (fp->f_r >= fp->f_ub.smb_size)
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sm_submore_x(fp);
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*--fp->f_p = c;
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fp->f_r++;
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return c;
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}
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fp->f_flags &= ~SMFEOF;
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/*
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** If we can handle this by simply backing up, do so,
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** but never replace the original character.
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** (This makes sscanf() work when scanning `const' data.)
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*/
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if (fp->f_bf.smb_base != NULL && fp->f_p > fp->f_bf.smb_base &&
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fp->f_p[-1] == c)
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{
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fp->f_p--;
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fp->f_r++;
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return c;
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}
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/*
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** Create an ungetc buffer.
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** Initially, we will use the `reserve' buffer.
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*/
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fp->f_ur = fp->f_r;
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fp->f_up = fp->f_p;
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fp->f_ub.smb_base = fp->f_ubuf;
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fp->f_ub.smb_size = sizeof(fp->f_ubuf);
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fp->f_ubuf[sizeof(fp->f_ubuf) - 1] = c;
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fp->f_p = &fp->f_ubuf[sizeof(fp->f_ubuf) - 1];
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fp->f_r = 1;
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return c;
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}
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