Add x qualifier to fopen to support exlusive open

This commit is contained in:
Gregory Nutt 2014-01-07 17:18:38 -06:00
parent c5f9b8768e
commit e3b12cbaa9
2 changed files with 57 additions and 40 deletions

View File

@ -6386,4 +6386,6 @@
* include/sys/types.h: Add a bogus rsize_t type (2014-1-7).
* libc/stdio/lib_gets_s.c: Add a quick'n'dirty implementation of
gets_s() which replaces gets() in C11 (2014-1-7).
* libc/stdio/lib_fopen.c: Add support for new C11 exclusive open
("x") (2014-1-7)

View File

@ -44,6 +44,7 @@
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include "lib_internal.h"
@ -52,21 +53,25 @@
* 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_PLUS (1 << 3) /* Bit 3: "{r|w|a|b|x}+" open for update (reading
* and writing) */
#define MODE_B (1 << 4) /* Bit 4: "{r|w|a|x|+}b" Binary mode */
#define MODE_X (1 << 5) /* Bit 5: "{r|w|a|b|+}x" Open exclusive mode */
#define MODE_NONE 0 /* No access mode determined */
#define MODE_MASK (MODE_R | MODE_W | MODE_A)
/****************************************************************************
* 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
****************************************************************************/
@ -77,15 +82,12 @@ enum open_mode_e
static int lib_mode2oflags(FAR const char *mode)
{
enum open_mode_e state;
unsigned int state;
int oflags;
/* Verify that a mode string was provided. No error is */
/* Verify that a mode string was provided. */
if (!mode)
{
goto errout;
}
DEBUGASSERT(mode);
/* Parse the mode string to determine the corresponding open flags */
@ -96,7 +98,7 @@ static int lib_mode2oflags(FAR const char *mode)
{
switch (*mode)
{
/* Open for read access ("r", "r[+]", "r[b]", "r[b+]", or "r[+b]") */
/* Open for read access ("r{b|x|+}") */
case 'r' :
if (state == MODE_NONE)
@ -112,14 +114,14 @@ static int lib_mode2oflags(FAR const char *mode)
}
break;
/* Open for write access ("w", "w[+]", "w[b]", "w[b+]", or "w[+b]") */
/* 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;
oflags = (O_WROK | O_CREAT | O_TRUNC);
state = MODE_W;
}
else
@ -128,7 +130,7 @@ static int lib_mode2oflags(FAR const char *mode)
}
break;
/* Open for write/append access ("a", "a[+]", "a[b]", "a[b+]", or "a[+b]") */
/* Open for write/append access ("a{b|x|+}") */
case 'a' :
if (state == MODE_NONE)
@ -144,49 +146,47 @@ static int lib_mode2oflags(FAR const char *mode)
}
break;
/* Open for update access ("[r]+", "[rb]+]", "[r]+[b]", "[w]+",
* "[wb]+]", "[w]+[b]", "[a]+", "[ab]+]", "[a]+[b]")
*/
/* Open for update access ("{r|w|a|b|x}+") */
case '+' :
switch (state)
switch (state & MODE_MASK)
{
case MODE_R:
{
/* Retain any binary mode selection */
/* Retain any binary and exclusive mode selections */
oflags &= O_BINARY;
oflags &= (O_BINARY | O_EXCL);
/* Open for read/write access */
oflags |= O_RDWR;
state = MODE_RPLUS;
state |= MODE_PLUS;
}
break;
case MODE_W:
{
/* Retain any binary mode selection */
/* Retain any binary and exclusive mode selections */
oflags &= O_BINARY;
oflags &= (O_BINARY | O_EXCL);
/* Open for write read/access, truncating any existing file */
oflags |= O_RDWR|O_CREAT|O_TRUNC;
state = MODE_WPLUS;
oflags |= (O_RDWR | O_CREAT | O_TRUNC);
state |= MODE_PLUS;
}
break;
case MODE_A:
{
/* Retain any binary mode selection */
/* Retain any binary and exclusive mode selections */
oflags &= O_BINARY;
oflags &= (O_BINARY | O_EXCL);
/* Read from the beginning of the file; write to the end */
oflags |= O_RDWR|O_CREAT|O_APPEND;
state = MODE_APLUS;
oflags |= (O_RDWR | O_CREAT | O_APPEND);
state |= MODE_PLUS;
}
break;
@ -196,16 +196,31 @@ static int lib_mode2oflags(FAR const char *mode)
}
break;
/* Open for binary access ("[r]b", "[r]b[+]", "[r+]b", "[w]b",
* "[w]b[+]", "[w+]b", "[a]b", "[a]b[+]", "[a+]b")
*/
/* Open for binary access ("{r|w|a|x|+}b") */
case 'b' :
if (state != MODE_NONE)
if ((state & MODE_MASK) != MODE_NONE)
{
/* The file is opened in binary mode */
oflags |= O_BINARY;
state |= MODE_B;
}
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;
state |= MODE_X;
}
else
{