diff options
Diffstat (limited to 'nuttx/lib/stdio/lib_fopen.c')
-rw-r--r-- | nuttx/lib/stdio/lib_fopen.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/nuttx/lib/stdio/lib_fopen.c b/nuttx/lib/stdio/lib_fopen.c new file mode 100644 index 000000000..52e44c59d --- /dev/null +++ b/nuttx/lib/stdio/lib_fopen.c @@ -0,0 +1,299 @@ +/**************************************************************************** + * lib/stdio/lib_fopen.c + * + * Copyright (C) 2007-2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <string.h> +#include <errno.h> + +#include "lib_internal.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +enum open_mode_e +{ + MODE_NONE = 0, /* No access mode determined */ + MODE_R, /* "r" or "rb" open for reading */ + MODE_W, /* "w" or "wb" open for writing, truncating or creating file */ + MODE_A, /* "a" or "ab" open for writing, appending to file */ + MODE_RPLUS, /* "r+", "rb+", or "r+b" open for update (reading and writing) */ + MODE_WPLUS, /* "w+", "wb+", or "w+b" open for update, truncating or creating file */ + MODE_APLUS, /* "a+", "ab+", or "a+b" open for update, appending to file */ +}; + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: lib_mode2oflags + ****************************************************************************/ + +static int lib_mode2oflags(FAR const char *mode) +{ + enum open_mode_e state; + int oflags; + + /* Verify that a mode string was provided. No error is */ + + if (!mode) + { + goto errout; + } + + /* 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", "r[+]", "r[b]", "r[b+]", or "r[+b]") */ + + case 'r' : + if (state == MODE_NONE) + { + /* Open for read access */ + + oflags = O_RDOK; + state = MODE_R; + } + else + { + goto errout; + } + break; + + /* Open for write access ("w", "w[+]", "w[b]", "w[b+]", or "w[+b]") */ + + case 'w' : + if (state == MODE_NONE) + { + /* Open for write access, truncating any existing file */ + + oflags = O_WROK|O_CREAT|O_TRUNC; + state = MODE_W; + } + else + { + goto errout; + } + break; + + /* Open for write/append access ("a", "a[+]", "a[b]", "a[b+]", or "a[+b]") */ + + case 'a' : + if (state == MODE_NONE) + { + /* Write to the end of the file */ + + oflags = O_WROK|O_CREAT|O_APPEND; + state = MODE_A; + } + else + { + goto errout; + } + break; + + /* Open for update access ("[r]+", "[rb]+]", "[r]+[b]", "[w]+", + * "[wb]+]", "[w]+[b]", "[a]+", "[ab]+]", "[a]+[b]") + */ + + case '+' : + switch (state) + { + case MODE_R: + { + /* Retain any binary mode selection */ + + oflags &= O_BINARY; + + /* Open for read/write access */ + + oflags |= O_RDWR; + state = MODE_RPLUS; + } + break; + + case MODE_W: + { + /* Retain any binary mode selection */ + + oflags &= O_BINARY; + + /* Open for write read/access, truncating any existing file */ + + oflags |= O_RDWR|O_CREAT|O_TRUNC; + state = MODE_WPLUS; + } + break; + + case MODE_A: + { + /* Retain any binary mode selection */ + + oflags &= O_BINARY; + + /* Read from the beginning of the file; write to the end */ + + oflags |= O_RDWR|O_CREAT|O_APPEND; + state = MODE_APLUS; + } + break; + + default: + goto errout; + break; + } + break; + + /* Open for binary access ("[r]b", "[r]b[+]", "[r+]b", "[w]b", + * "[w]b[+]", "[w+]b", "[a]b", "[a]b[+]", "[a+]b") + */ + + case 'b' : + if (state != MODE_NONE) + { + /* The file is opened in binary mode */ + + oflags |= O_BINARY; + } + 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; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: fdopen + ****************************************************************************/ + +FAR FILE *fdopen(int fd, FAR const char *mode) +{ + FAR FILE *ret = NULL; + int oflags; + + /* Map the open mode string to open flags */ + + oflags = lib_mode2oflags(mode); + if (oflags >= 0) + { + ret = fs_fdopen(fd, oflags, NULL); + } + + return ret; +} + +/**************************************************************************** + * Name: fopen + ****************************************************************************/ + +FAR FILE *fopen(FAR const char *path, FAR const char *mode) +{ + FAR FILE *ret = NULL; + int oflags; + int fd; + + /* 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 fdopen() the fil using the file + * desciptor 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); + if (!ret) + { + /* Don't forget to close the file descriptor if any other + * failures are reported by fdopen(). + */ + + (void)close(fd); + } + } + return ret; +} |