/****************************************************************************
* libs/libc/stdio/lib_fopen.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include "libc.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Open mode flags */
#define MODE_R (1 << 0) /* Bit 0: "r{b|x|+}" open for reading */
#define MODE_W (1 << 1) /* Bit 1: "w{b|x|+}" open for writing, truncating,
* or creating file */
#define MODE_A (1 << 2) /* Bit 2: "a{b|x|+}" open for writing, appending
* the to file */
#define MODE_NONE 0 /* No access mode determined */
#define MODE_MASK (MODE_R | MODE_W | MODE_A)
#define FLAG_KEEP (O_TEXT | O_CLOEXEC | O_EXCL)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: fdopen
****************************************************************************/
FAR FILE *fdopen(int fd, FAR const char *mode)
{
FAR FILE *filep = NULL;
int oflags;
int ret;
/* Map the open mode string to open flags */
oflags = lib_mode2oflags(mode);
if (oflags >= 0)
{
ret = fs_fdopen(fd, oflags, NULL, &filep);
if (ret < 0)
{
set_errno(-ret);
}
}
return filep;
}
/****************************************************************************
* Name: fopen
****************************************************************************/
FAR FILE *fopen(FAR const char *path, FAR const char *mode)
{
FAR FILE *filep = NULL;
int oflags;
int fd;
int ret;
/* Map the open mode string to open flags */
oflags = lib_mode2oflags(mode);
if (oflags < 0)
{
return NULL;
}
/* Open the file */
fd = open(path, oflags, 0666);
/* If the open was successful, then call fdopen() using the file
* descriptor returned by open. If open failed, then just return the
* NULL stream -- open() has already set the errno.
*/
if (fd >= 0)
{
ret = fs_fdopen(fd, oflags, NULL, &filep);
if (ret < 0)
{
/* Don't forget to close the file descriptor if any other
* failures are reported by fdopen().
*/
close(fd);
set_errno(-ret);
filep = NULL;
}
}
return filep;
}
/****************************************************************************
* Name: lib_mode2oflags
****************************************************************************/
int lib_mode2oflags(FAR const char *mode)
{
unsigned int state;
int oflags;
/* Verify that a mode string was provided. */
DEBUGASSERT(mode);
/* Parse the mode string to determine the corresponding open flags */
state = MODE_NONE;
oflags = 0;
for (; *mode; mode++)
{
switch (*mode)
{
/* Open for read access ("r{b|x|+}") */
case 'r' :
if (state == MODE_NONE)
{
/* Open for read access */
oflags = O_RDOK | O_TEXT;
state = MODE_R;
}
else
{
goto errout;
}
break;
/* Open for write access ("w{b|x|+}") */
case 'w' :
if (state == MODE_NONE)
{
/* Open for write access, truncating any existing file */
oflags = O_WROK | O_CREAT | O_TRUNC | O_TEXT;
state = MODE_W;
}
else
{
goto errout;
}
break;
/* Open for write/append access ("a{b|x|+}") */
case 'a' :
if (state == MODE_NONE)
{
/* Write to the end of the file */
oflags = O_WROK | O_CREAT | O_APPEND | O_TEXT;
state = MODE_A;
}
else
{
goto errout;
}
break;
/* Open for update access ("{r|w|a|b|x}+") */
case '+' :
switch (state & MODE_MASK)
{
case MODE_R:
{
/* Retain any binary and exclusive mode selections */
oflags &= FLAG_KEEP;
/* Open for read/write access */
oflags |= O_RDWR;
}
break;
case MODE_W:
{
/* Retain any binary and exclusive mode selections */
oflags &= FLAG_KEEP;
/* Open for write read/access, truncating any existing
* file.
*/
oflags |= O_RDWR | O_CREAT | O_TRUNC;
}
break;
case MODE_A:
{
/* Retain any binary and exclusive mode selections */
oflags &= FLAG_KEEP;
/* Read from the beginning of the file; write to the
* end,
*/
oflags |= O_RDWR | O_CREAT | O_APPEND;
}
break;
default:
goto errout;
break;
}
break;
/* Open for binary access ("{r|w|a|x|+}b") */
case 'b' :
if ((state & MODE_MASK) != MODE_NONE)
{
/* The file is opened in binary mode */
oflags &= ~O_TEXT;
}
else
{
goto errout;
}
break;
/* Open for close on execute */
case 'e' :
if ((state & MODE_MASK) != MODE_NONE)
{
/* The file will be closed on execute */
oflags |= O_CLOEXEC;
}
else
{
goto errout;
}
break;
/* Open for exclusive access ("{r|w|a|b|+}x") */
case 'x' :
if ((state & MODE_MASK) != MODE_NONE)
{
/* The file is opened in exclusive mode */
oflags |= O_EXCL;
}
else
{
goto errout;
}
break;
/* Open for text (translated) access ("{r|w|a|x|+}t") */
case 't' :
if ((state & MODE_MASK) != MODE_NONE)
{
/* The file is opened in text mode */
oflags |= O_TEXT;
}
else
{
goto errout;
}
break;
/* Unrecognized or unsupported mode */
default:
goto errout;
break;
}
}
return oflags;
/* Both fopen and fdopen should fail with errno == EINVAL if the mode
* string is invalid.
*/
errout:
set_errno(EINVAL);
return ERROR;
}