307 lines
8.6 KiB
C
307 lines
8.6 KiB
C
/****************************************************************************
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* libc/stdio/lib_fopen.c
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*
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* Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include "lib_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Open mode flags */
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#define MODE_R (1 << 0) /* Bit 0: "r{b|x|+}" open for reading */
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#define MODE_W (1 << 1) /* Bit 1: "w{b|x|+}" open for writing, truncating,
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* or creating file */
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#define MODE_A (1 << 2) /* Bit 2: "a{b|x|+}" open for writing, appending
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* the to file */
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#define MODE_PLUS (1 << 3) /* Bit 3: "{r|w|a|b|x}+" open for update (reading
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* and writing) */
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#define MODE_B (1 << 4) /* Bit 4: "{r|w|a|x|+}b" Binary mode */
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#define MODE_X (1 << 5) /* Bit 5: "{r|w|a|b|+}x" Open exclusive mode */
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#define MODE_NONE 0 /* No access mode determined */
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#define MODE_MASK (MODE_R | MODE_W | MODE_A)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fdopen
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****************************************************************************/
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FAR FILE *fdopen(int fd, FAR const char *mode)
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{
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FAR FILE *ret = NULL;
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int oflags;
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/* Map the open mode string to open flags */
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oflags = lib_mode2oflags(mode);
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if (oflags >= 0)
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{
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ret = fs_fdopen(fd, oflags, NULL);
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}
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return ret;
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}
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/****************************************************************************
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* Name: fopen
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****************************************************************************/
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FAR FILE *fopen(FAR const char *path, FAR const char *mode)
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{
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FAR FILE *ret = NULL;
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int oflags;
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int fd;
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/* Map the open mode string to open flags */
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oflags = lib_mode2oflags(mode);
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if (oflags < 0)
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{
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return NULL;
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}
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/* Open the file */
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fd = open(path, oflags, 0666);
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/* If the open was successful, then fdopen() the fil using the file
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* descriptor returned by open. If open failed, then just return the
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* NULL stream -- open() has already set the errno.
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*/
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if (fd >= 0)
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{
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ret = fs_fdopen(fd, oflags, NULL);
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if (!ret)
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{
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/* Don't forget to close the file descriptor if any other
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* failures are reported by fdopen().
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*/
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(void)close(fd);
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}
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}
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return ret;
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}
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/****************************************************************************
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* Name: lib_mode2oflags
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****************************************************************************/
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int lib_mode2oflags(FAR const char *mode)
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{
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unsigned int state;
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int oflags;
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/* Verify that a mode string was provided. */
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DEBUGASSERT(mode);
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/* Parse the mode string to determine the corresponding open flags */
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state = MODE_NONE;
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oflags = 0;
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for (; *mode; mode++)
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{
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switch (*mode)
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{
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/* Open for read access ("r{b|x|+}") */
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case 'r' :
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if (state == MODE_NONE)
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{
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/* Open for read access */
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oflags = O_RDOK;
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state = MODE_R;
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}
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else
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{
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goto errout;
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}
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break;
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/* Open for write access ("w{b|x|+}") */
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case 'w' :
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if (state == MODE_NONE)
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{
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/* Open for write access, truncating any existing file */
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oflags = (O_WROK | O_CREAT | O_TRUNC);
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state = MODE_W;
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}
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else
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{
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goto errout;
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}
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break;
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/* Open for write/append access ("a{b|x|+}") */
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case 'a' :
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if (state == MODE_NONE)
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{
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/* Write to the end of the file */
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oflags = O_WROK | O_CREAT | O_APPEND;
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state = MODE_A;
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}
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else
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{
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goto errout;
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}
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break;
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/* Open for update access ("{r|w|a|b|x}+") */
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case '+' :
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switch (state & MODE_MASK)
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{
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case MODE_R:
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{
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/* Retain any binary and exclusive mode selections */
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oflags &= (O_BINARY | O_EXCL);
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/* Open for read/write access */
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oflags |= O_RDWR;
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state |= MODE_PLUS;
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}
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break;
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case MODE_W:
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{
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/* Retain any binary and exclusive mode selections */
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oflags &= (O_BINARY | O_EXCL);
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/* Open for write read/access, truncating any existing file */
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oflags |= (O_RDWR | O_CREAT | O_TRUNC);
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state |= MODE_PLUS;
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}
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break;
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case MODE_A:
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{
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/* Retain any binary and exclusive mode selections */
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oflags &= (O_BINARY | O_EXCL);
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/* Read from the beginning of the file; write to the end */
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oflags |= (O_RDWR | O_CREAT | O_APPEND);
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state |= MODE_PLUS;
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}
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break;
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default:
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goto errout;
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break;
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}
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break;
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/* Open for binary access ("{r|w|a|x|+}b") */
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case 'b' :
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if ((state & MODE_MASK) != MODE_NONE)
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{
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/* The file is opened in binary mode */
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oflags |= O_BINARY;
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state |= MODE_B;
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}
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else
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{
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goto errout;
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}
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break;
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/* Open for exclusive access ("{r|w|a|b|+}x") */
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case 'X' :
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if ((state & MODE_MASK) != MODE_NONE)
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{
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/* The file is opened in exclusive mode */
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oflags |= O_EXCL;
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state |= MODE_X;
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}
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else
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{
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goto errout;
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}
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break;
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/* Unrecognized or unsupported mode */
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default:
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goto errout;
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break;
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}
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}
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return oflags;
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/* Both fopen and fdopen should fail with errno == EINVAL if the mode
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* string is invalid.
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*/
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errout:
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set_errno(EINVAL);
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return ERROR;
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}
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