[resend,1/2] libio: fmemopen rewrite to POSIX compliance
diff mbox

Message ID 5486EE5C.9040506@linux.vnet.ibm.com
State New
Headers show

Commit Message

Adhemerval Zanella Dec. 9, 2014, 12:43 p.m. UTC
This patch added a new fmemopen version, for glibc 2.21, that aims to be
POSIX complaint.  It fixes some long-stading glibc fmemopen issues, such
as:

* it changes the way fseek with SEEK_END works on fmemopen to seek
  relative to buffer size instead of first '\0'.  This is default mode and
  'b' opening mode does not change internal behavior (bz#6544).

* fix apending opening mode to use as start position either first null
  byte of len specified in function call (bz#13152 and #13151).

* remove binary option 'b' and internal different handling (bz#12836)

* fix seek/SEE_END with negative values (bz#14292).

A compatibility symbol is provided to with old behavior for older symbols
version (2.2.5).

Tested on powerpc64, powerpc32, and x86_64.

--

	[BZ #6544]
	[BZ #11216]
	[BZ #12836]
	[BZ #13151]
	[BZ #13152]
	[BZ #14292]
	* include/stdio.h (fmemopen): Remove hidden prototype.
	(__fmemopen): Add new hidden prototype.
	* libio/Makefile: Add oldfmemopen object.
	* libio/Versions [GLIBC_2.21]: Add new fmemopen symbol.
	* libio/fmemopen.c (__fmemopen): Function rewrite to be POSIX
	compliance.
	* libio/oldfmemopen.c: New file: old fmemopen implementation for
	symbol compatibility.
	* stdio-common/Makefile [tests]: Add new tst-fmemopen3.
	* stdio-common/psiginfo.c [psiginfo]: Call __fmemopen instead of
	fmemopen.
	* stdio-common/tst-fmemopen3.c: New file: more fmemopen tests, focus
	on append and read mode.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist [GLIBC_2.21]: Add
	fmemopen.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist [GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/i386/libc.abilist [GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/sh/libc.abilist [GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
	[GLIBC_2.21]: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist [GLIBC_2.21]:
	Likewise.
	* sysdeps/unix/sysv/linux/hppa/libc.abilist [GLIBC_2.21]: Likewise.

--

--

Comments

Adhemerval Zanella Jan. 6, 2015, 5:26 p.m. UTC | #1
Ping.

On 09-12-2014 10:43, Adhemerval Zanella wrote:
> This patch added a new fmemopen version, for glibc 2.21, that aims to be
> POSIX complaint.  It fixes some long-stading glibc fmemopen issues, such
> as:
>
> * it changes the way fseek with SEEK_END works on fmemopen to seek
>   relative to buffer size instead of first '\0'.  This is default mode and
>   'b' opening mode does not change internal behavior (bz#6544).
>
> * fix apending opening mode to use as start position either first null
>   byte of len specified in function call (bz#13152 and #13151).
>
> * remove binary option 'b' and internal different handling (bz#12836)
>
> * fix seek/SEE_END with negative values (bz#14292).
>
> A compatibility symbol is provided to with old behavior for older symbols
> version (2.2.5).
>
> Tested on powerpc64, powerpc32, and x86_64.
>
> --
>
> 	[BZ #6544]
> 	[BZ #11216]
> 	[BZ #12836]
> 	[BZ #13151]
> 	[BZ #13152]
> 	[BZ #14292]
> 	* include/stdio.h (fmemopen): Remove hidden prototype.
> 	(__fmemopen): Add new hidden prototype.
> 	* libio/Makefile: Add oldfmemopen object.
> 	* libio/Versions [GLIBC_2.21]: Add new fmemopen symbol.
> 	* libio/fmemopen.c (__fmemopen): Function rewrite to be POSIX
> 	compliance.
> 	* libio/oldfmemopen.c: New file: old fmemopen implementation for
> 	symbol compatibility.
> 	* stdio-common/Makefile [tests]: Add new tst-fmemopen3.
> 	* stdio-common/psiginfo.c [psiginfo]: Call __fmemopen instead of
> 	fmemopen.
> 	* stdio-common/tst-fmemopen3.c: New file: more fmemopen tests, focus
> 	on append and read mode.
> 	* sysdeps/unix/sysv/linux/aarch64/libc.abilist [GLIBC_2.21]: Add
> 	fmemopen.
> 	* sysdeps/unix/sysv/linux/alpha/libc.abilist [GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/i386/libc.abilist [GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/ia64/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/microblaze/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/sh/libc.abilist [GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
> 	[GLIBC_2.21]: Likewise.
> 	* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist [GLIBC_2.21]:
> 	Likewise.
> 	* sysdeps/unix/sysv/linux/hppa/libc.abilist [GLIBC_2.21]: Likewise.
>
> --
>
> diff --git a/NEWS b/NEWS
> index 1b08d40..bd467e7 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -9,12 +9,12 @@ Version 2.21
>
>  * The following bugs are resolved with this release:
>
> -  6652, 12926, 13862, 14132, 14138, 14171, 14498, 15215, 15884, 16469,
> -  16619, 16740, 16857, 17192, 17266, 17344, 17363, 17370, 17371, 17411,
> -  17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, 17571,
> -  17572, 17573, 17574, 17581, 17582, 17583, 17584, 17585, 17589, 17594,
> -  17601, 17608, 17616, 17625, 17633, 17647, 17653, 17664, 17665, 17668,
> -  17682.
> +  6544, 6652, 11216, 12836, 12926, 13151, 13152, 13862, 14132, 14138, 
> +  14171, 14292, 14498, 15215, 15884, 16469, 16619, 16740, 16857, 17192,
> +  17266, 17344, 17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501,
> +  17506, 17508, 17522, 17555, 17570, 17571, 17572, 17573, 17574, 17581,
> +  17582, 17583, 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625,
> +  17633, 17647, 17653, 17664, 17665, 17668, 17682.
>
>  * CVE-2104-7817 The wordexp function could ignore the WRDE_NOCMD flag
>    under certain input conditions resulting in the execution of a shell for
> diff --git a/include/stdio.h b/include/stdio.h
> index 0010607..e480701 100644
> --- a/include/stdio.h
> +++ b/include/stdio.h
> @@ -158,7 +158,6 @@ libc_hidden_proto (fgets_unlocked)
>  extern __typeof (fgets_unlocked) __fgets_unlocked;
>  libc_hidden_proto (__fgets_unlocked)
>  libc_hidden_proto (fputs_unlocked)
> -libc_hidden_proto (fmemopen)
>  libc_hidden_proto (open_memstream)
>  libc_hidden_proto (__libc_fatal)
>  libc_hidden_proto (__vsprintf_chk)
> @@ -186,6 +185,9 @@ gets (char *__str)
>  }
>  #  endif
>
> +extern FILE * __fmemopen (void *buf, size_t len, const char *mode);
> +libc_hidden_proto (__fmemopen)
> +
>  __END_DECLS
>  # endif
>
> diff --git a/libio/Makefile b/libio/Makefile
> index 2742128..c1dec9a 100644
> --- a/libio/Makefile
> +++ b/libio/Makefile
> @@ -46,7 +46,7 @@ routines	:=							      \
>  	__fbufsize __freading __fwriting __freadable __fwritable __flbf	      \
>  	__fpurge __fpending __fsetlocking				      \
>  									      \
> -	libc_fatal fmemopen
> +	libc_fatal fmemopen oldfmemopen
>
>  tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc   \
>  	tst_wprintf2 tst-widetext test-fmemopen tst-ext tst-ext2 \
> diff --git a/libio/Versions b/libio/Versions
> index 8df89d2..8102da0 100644
> --- a/libio/Versions
> +++ b/libio/Versions
> @@ -148,6 +148,10 @@ libc {
>    GLIBC_2.4 {
>      open_wmemstream;
>    }
> +  GLIBC_2.21 {
> +    # f*
> +    fmemopen;
> +  }
>    GLIBC_PRIVATE {
>      # Used by NPTL and librt
>      __libc_fatal;
> diff --git a/libio/fmemopen.c b/libio/fmemopen.c
> index aee2696..20b646c 100644
> --- a/libio/fmemopen.c
> +++ b/libio/fmemopen.c
> @@ -1,7 +1,6 @@
> -/* Fmemopen implementation.
> -   Copyright (C) 2000-2014 Free Software Foundation, Inc.
> +/* fmemopen implementation.
> +   Copyright (C) 2014 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
> -   Contributed by Hanno Mueller, kontakt@hanno.de, 2000.
>
>     The GNU C Library is free software; you can redistribute it and/or
>     modify it under the terms of the GNU Lesser General Public
> @@ -17,54 +16,10 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>
> -/*
> - * fmemopen() - "my" version of a string stream
> - * Hanno Mueller, kontakt@hanno.de
> - *
> - *
> - * I needed fmemopen() for an application that I currently work on,
> - * but couldn't find it in libio. The following snippet of code is an
> - * attempt to implement what glibc's documentation describes.
> - *
> - *
> - *
> - * I already see some potential problems:
> - *
> - * - I never used the "original" fmemopen(). I am sure that "my"
> - *   fmemopen() behaves differently than the original version.
> - *
> - * - The documentation doesn't say wether a string stream allows
> - *   seeks. I checked the old fmemopen implementation in glibc's stdio
> - *   directory, wasn't quite able to see what is going on in that
> - *   source, but as far as I understand there was no seek there. For
> - *   my application, I needed fseek() and ftell(), so it's here.
> - *
> - * - "append" mode and fseek(p, SEEK_END) have two different ideas
> - *   about the "end" of the stream.
> - *
> - *   As described in the documentation, when opening the file in
> - *   "append" mode, the position pointer will be set to the first null
> - *   character of the string buffer (yet the buffer may already
> - *   contain more data). For fseek(), the last byte of the buffer is
> - *   used as the end of the stream.
> - *
> - * - It is unclear to me what the documentation tries to say when it
> - *   explains what happens when you use fmemopen with a NULL
> - *   buffer.
> - *
> - *   Quote: "fmemopen [then] allocates an array SIZE bytes long. This
> - *   is really only useful if you are going to write things to the
> - *   buffer and then read them back in again."
> - *
> - *   What does that mean if the original fmemopen() did not allow
> - *   seeking? How do you read what you just wrote without seeking back
> - *   to the beginning of the stream?
> - *
> - * - I think there should be a second version of fmemopen() that does
> - *   not add null characters for each write. (At least in my
> - *   application, I am not actually using strings but binary data and
> - *   so I don't need the stream to add null characters on its own.)
> - */
> +/* fmemopen() from 2.21 and forward works as defined by POSIX.  It also
> +   provides an older symbol, version 2.2.5, that behaves different regarding
> +   SEEK_END (libio/oldfmemopen.c).  */
> +
>
>  #include <errno.h>
>  #include <libio.h>
> @@ -79,25 +34,23 @@
>  typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
>  struct fmemopen_cookie_struct
>  {
> -  char *buffer;
> -  int mybuffer;
> -  int binmode;
> -  size_t size;
> -  _IO_off64_t pos;
> -  size_t maxpos;
> +  char        *buffer;   /* memory buffer.  */
> +  int         mybuffer;  /* own allocated buffer?  */
> +  int         append;    /* buffer openened for append?  */
> +  size_t      size;      /* buffer length in bytes.  */
> +  _IO_off64_t pos;       /* current position at the buffer.  */
> +  size_t      maxpos;    /* max position in buffer.  */
>  };
>
>
>  static ssize_t
>  fmemopen_read (void *cookie, char *b, size_t s)
>  {
> -  fmemopen_cookie_t *c;
> -
> -  c = (fmemopen_cookie_t *) cookie;
> +  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
>
> -  if (c->pos + s > c->size)
> +  if (c->pos + s > c->maxpos)
>      {
> -      if ((size_t) c->pos == c->size)
> +      if ((size_t) c->pos == c->maxpos)
>  	return 0;
>        s = c->size - c->pos;
>      }
> @@ -115,29 +68,28 @@ fmemopen_read (void *cookie, char *b, size_t s)
>  static ssize_t
>  fmemopen_write (void *cookie, const char *b, size_t s)
>  {
> -  fmemopen_cookie_t *c;
> +  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;;
> +  _IO_off64_t pos = c->append ? c->maxpos : c->pos;
>    int addnullc;
>
> -  c = (fmemopen_cookie_t *) cookie;
> -
> -  addnullc = c->binmode == 0 && (s == 0 || b[s - 1] != '\0');
> +  addnullc = (s == 0 || b[s - 1] != '\0');
>
> -  if (c->pos + s + addnullc > c->size)
> +  if (pos + s + addnullc > c->size)
>      {
> -      if ((size_t) (c->pos + addnullc) == c->size)
> +      if ((size_t) (pos + addnullc) >= c->size)
>  	{
>  	  __set_errno (ENOSPC);
>  	  return 0;
>  	}
> -      s = c->size - c->pos - addnullc;
> +      s = c->size - pos - addnullc;
>      }
>
> -  memcpy (&(c->buffer[c->pos]), b, s);
> +  memcpy (&(c->buffer[pos]), b, s);
>
> -  c->pos += s;
> -  if ((size_t) c->pos > c->maxpos)
> +  pos += s;
> +  if ((size_t) pos > c->maxpos)
>      {
> -      c->maxpos = c->pos;
> +      c->maxpos = pos;
>        if (addnullc)
>  	c->buffer[c->maxpos] = '\0';
>      }
> @@ -150,9 +102,7 @@ static int
>  fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
>  {
>    _IO_off64_t np;
> -  fmemopen_cookie_t *c;
> -
> -  c = (fmemopen_cookie_t *) cookie;
> +  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
>
>    switch (w)
>      {
> @@ -165,7 +115,7 @@ fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
>        break;
>
>      case SEEK_END:
> -      np = (c->binmode ? c->size : c->maxpos) - *p;
> +      np = c->maxpos + *p;
>        break;
>
>      default:
> @@ -184,9 +134,7 @@ fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
>  static int
>  fmemopen_close (void *cookie)
>  {
> -  fmemopen_cookie_t *c;
> -
> -  c = (fmemopen_cookie_t *) cookie;
> +  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
>
>    if (c->mybuffer)
>      free (c->buffer);
> @@ -197,18 +145,11 @@ fmemopen_close (void *cookie)
>
>
>  FILE *
> -fmemopen (void *buf, size_t len, const char *mode)
> +__fmemopen (void *buf, size_t len, const char *mode)
>  {
>    cookie_io_functions_t iof;
>    fmemopen_cookie_t *c;
>
> -  if (__glibc_unlikely (len == 0))
> -    {
> -    einval:
> -      __set_errno (EINVAL);
> -      return NULL;
> -    }
> -
>    c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
>    if (c == NULL)
>      return NULL;
> @@ -231,26 +172,38 @@ fmemopen (void *buf, size_t len, const char *mode)
>        if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
>  	{
>  	  free (c);
> -	  goto einval;
> +	  __set_errno (EINVAL);
> +	  return NULL;
>  	}
>
>        c->buffer = buf;
>
> -      if (mode[0] == 'w')
> +      /* POSIX states that w+ mode should truncate the buffer.  */
> +      if (mode[0] == 'w' && mode[1] == '+')
>  	c->buffer[0] = '\0';
>
>        c->maxpos = strnlen (c->buffer, len);
>      }
>
> +
> +  /* Mode   |  starting position (cookie::pos) |          size (cookie::size)
> +   * ------ |----------------------------------|-----------------------------
> +   * read   |          beginning of the buffer |                size argument
> +   * write  |          beginning of the buffer |                         zero
> +   * append |    first null or size buffer + 1 |  first null or size argument
> +   */
> +
>    c->size = len;
>
> -  if (mode[0] == 'a')
> +  if (mode[0] == 'r')
> +    c->maxpos = len;
> +
> +  c->append = mode[0] == 'a';
> +  if (c->append)
>      c->pos = c->maxpos;
>    else
>      c->pos = 0;
>
> -  c->binmode = mode[0] != '\0' && mode[1] == 'b';
> -
>    iof.read = fmemopen_read;
>    iof.write = fmemopen_write;
>    iof.seek = fmemopen_seek;
> @@ -258,4 +211,5 @@ fmemopen (void *buf, size_t len, const char *mode)
>
>    return _IO_fopencookie (c, mode, iof);
>  }
> -libc_hidden_def (fmemopen)
> +libc_hidden_def (__fmemopen)
> +versioned_symbol (libc, __fmemopen, fmemopen, GLIBC_2_21);
> diff --git a/libio/oldfmemopen.c b/libio/oldfmemopen.c
> new file mode 100644
> index 0000000..88f8473
> --- /dev/null
> +++ b/libio/oldfmemopen.c
> @@ -0,0 +1,265 @@
> +/* Fmemopen implementation.
> +   Copyright (C) 2000-2014 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +   Contributed by Hanno Mueller, kontakt@hanno.de, 2000.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +/*
> + * fmemopen() - "my" version of a string stream
> + * Hanno Mueller, kontakt@hanno.de
> + *
> + *
> + * I needed fmemopen() for an application that I currently work on,
> + * but couldn't find it in libio. The following snippet of code is an
> + * attempt to implement what glibc's documentation describes.
> + *
> + *
> + *
> + * I already see some potential problems:
> + *
> + * - I never used the "original" fmemopen(). I am sure that "my"
> + *   fmemopen() behaves differently than the original version.
> + *
> + * - The documentation doesn't say wether a string stream allows
> + *   seeks. I checked the old fmemopen implementation in glibc's stdio
> + *   directory, wasn't quite able to see what is going on in that
> + *   source, but as far as I understand there was no seek there. For
> + *   my application, I needed fseek() and ftell(), so it's here.
> + *
> + * - "append" mode and fseek(p, SEEK_END) have two different ideas
> + *   about the "end" of the stream.
> + *
> + *   As described in the documentation, when opening the file in
> + *   "append" mode, the position pointer will be set to the first null
> + *   character of the string buffer (yet the buffer may already
> + *   contain more data). For fseek(), the last byte of the buffer is
> + *   used as the end of the stream.
> + *
> + * - It is unclear to me what the documentation tries to say when it
> + *   explains what happens when you use fmemopen with a NULL
> + *   buffer.
> + *
> + *   Quote: "fmemopen [then] allocates an array SIZE bytes long. This
> + *   is really only useful if you are going to write things to the
> + *   buffer and then read them back in again."
> + *
> + *   What does that mean if the original fmemopen() did not allow
> + *   seeking? How do you read what you just wrote without seeking back
> + *   to the beginning of the stream?
> + *
> + * - I think there should be a second version of fmemopen() that does
> + *   not add null characters for each write. (At least in my
> + *   application, I am not actually using strings but binary data and
> + *   so I don't need the stream to add null characters on its own.)
> + */
> +
> +#include "libioP.h"
> +
> +#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_21)
> +
> +#include <errno.h>
> +#include <libio.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +#include <sys/types.h>
> +
> +
> +typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
> +struct fmemopen_cookie_struct
> +{
> +  char *buffer;
> +  int mybuffer;
> +  int binmode;
> +  size_t size;
> +  _IO_off64_t pos;
> +  size_t maxpos;
> +};
> +
> +
> +static ssize_t
> +fmemopen_read (void *cookie, char *b, size_t s)
> +{
> +  fmemopen_cookie_t *c;
> +
> +  c = (fmemopen_cookie_t *) cookie;
> +
> +  if (c->pos + s > c->size)
> +    {
> +      if ((size_t) c->pos == c->size)
> +	return 0;
> +      s = c->size - c->pos;
> +    }
> +
> +  memcpy (b, &(c->buffer[c->pos]), s);
> +
> +  c->pos += s;
> +  if ((size_t) c->pos > c->maxpos)
> +    c->maxpos = c->pos;
> +
> +  return s;
> +}
> +
> +
> +static ssize_t
> +fmemopen_write (void *cookie, const char *b, size_t s)
> +{
> +  fmemopen_cookie_t *c;
> +  int addnullc;
> +
> +  c = (fmemopen_cookie_t *) cookie;
> +
> +  addnullc = c->binmode == 0 && (s == 0 || b[s - 1] != '\0');
> +
> +  if (c->pos + s + addnullc > c->size)
> +    {
> +      if ((size_t) (c->pos + addnullc) == c->size)
> +	{
> +	  __set_errno (ENOSPC);
> +	  return 0;
> +	}
> +      s = c->size - c->pos - addnullc;
> +    }
> +
> +  memcpy (&(c->buffer[c->pos]), b, s);
> +
> +  c->pos += s;
> +  if ((size_t) c->pos > c->maxpos)
> +    {
> +      c->maxpos = c->pos;
> +      if (addnullc)
> +	c->buffer[c->maxpos] = '\0';
> +    }
> +
> +  return s;
> +}
> +
> +
> +static int
> +fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
> +{
> +  _IO_off64_t np;
> +  fmemopen_cookie_t *c;
> +
> +  c = (fmemopen_cookie_t *) cookie;
> +
> +  switch (w)
> +    {
> +    case SEEK_SET:
> +      np = *p;
> +      break;
> +
> +    case SEEK_CUR:
> +      np = c->pos + *p;
> +      break;
> +
> +    case SEEK_END:
> +      np = (c->binmode ? c->size : c->maxpos) - *p;
> +      break;
> +
> +    default:
> +      return -1;
> +    }
> +
> +  if (np < 0 || (size_t) np > c->size)
> +    return -1;
> +
> +  *p = c->pos = np;
> +
> +  return 0;
> +}
> +
> +
> +static int
> +fmemopen_close (void *cookie)
> +{
> +  fmemopen_cookie_t *c;
> +
> +  c = (fmemopen_cookie_t *) cookie;
> +
> +  if (c->mybuffer)
> +    free (c->buffer);
> +  free (c);
> +
> +  return 0;
> +}
> +
> +
> +FILE *
> +__old_fmemopen (void *buf, size_t len, const char *mode)
> +{
> +  cookie_io_functions_t iof;
> +  fmemopen_cookie_t *c;
> +
> +  if (__glibc_unlikely (len == 0))
> +    {
> +    einval:
> +      __set_errno (EINVAL);
> +      return NULL;
> +    }
> +
> +  c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
> +  if (c == NULL)
> +    return NULL;
> +
> +  c->mybuffer = (buf == NULL);
> +
> +  if (c->mybuffer)
> +    {
> +      c->buffer = (char *) malloc (len);
> +      if (c->buffer == NULL)
> +	{
> +	  free (c);
> +	  return NULL;
> +	}
> +      c->buffer[0] = '\0';
> +      c->maxpos = 0;
> +    }
> +  else
> +    {
> +      if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
> +	{
> +	  free (c);
> +	  goto einval;
> +	}
> +
> +      c->buffer = buf;
> +
> +      if (mode[0] == 'w')
> +	c->buffer[0] = '\0';
> +
> +      c->maxpos = strnlen (c->buffer, len);
> +    }
> +
> +  c->size = len;
> +
> +  if (mode[0] == 'a')
> +    c->pos = c->maxpos;
> +  else
> +    c->pos = 0;
> +
> +  c->binmode = mode[0] != '\0' && mode[1] == 'b';
> +
> +  iof.read = fmemopen_read;
> +  iof.write = fmemopen_write;
> +  iof.seek = fmemopen_seek;
> +  iof.close = fmemopen_close;
> +
> +  return _IO_fopencookie (c, mode, iof);
> +}
> +compat_symbol (libc, __old_fmemopen, fmemopen, GLIBC_2_2);
> +#endif
> diff --git a/stdio-common/Makefile b/stdio-common/Makefile
> index 5f8e534..5971e65 100644
> --- a/stdio-common/Makefile
> +++ b/stdio-common/Makefile
> @@ -57,7 +57,7 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
>  	 bug19 bug19a tst-popen2 scanf13 scanf14 scanf15 bug20 bug21 bug22 \
>  	 scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \
>  	 bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3 \
> -	 bug25 tst-printf-round bug26
> +	 bug25 tst-printf-round bug26 tst-fmemopen3
>
>  test-srcs = tst-unbputc tst-printf
>
> diff --git a/stdio-common/psiginfo.c b/stdio-common/psiginfo.c
> index 564d237..62a9671 100644
> --- a/stdio-common/psiginfo.c
> +++ b/stdio-common/psiginfo.c
> @@ -60,7 +60,7 @@ void
>  psiginfo (const siginfo_t *pinfo, const char *s)
>  {
>    char buf[512];
> -  FILE *fp = fmemopen (buf, sizeof (buf), "w");
> +  FILE *fp = __fmemopen (buf, sizeof (buf), "w");
>    if (fp == NULL)
>      {
>        const char *colon;
> diff --git a/stdio-common/tst-fmemopen3.c b/stdio-common/tst-fmemopen3.c
> new file mode 100644
> index 0000000..8cd211f
> --- /dev/null
> +++ b/stdio-common/tst-fmemopen3.c
> @@ -0,0 +1,206 @@
> +/* fmemopen tests for append and read mode.
> +   Copyright (C) 2014 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <assert.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/types.h>
> +
> +static void
> +print_buffer (const char *s, size_t n)
> +{
> +  size_t i;
> +  for (i=0; i<n; ++i)
> +    printf ("0x%02X (%c), ", s[i], s[i]);
> +}
> +
> +/* This test check append mode initial position (a/a+) based on POSIX defition
> +   (BZ#6544 and BZ#13151).  */
> +static int
> +do_test_write_append (const char *mode)
> +{
> +  char buf[32] = "testing buffer";
> +  char exp[32] = "testing bufferXX";
> +
> +  FILE *fp = fmemopen (buf, sizeof (buf), mode);
> +
> +  fflush (fp);
> +  fprintf (fp, "X");
> +  fseek (fp, 0, SEEK_SET);
> +  fprintf (fp, "X");
> +  fclose (fp);
> +
> +  if (strcmp (buf, exp) != 0)
> +    {
> +      printf ("%s: check failed: %s != %s\n", __FUNCTION__, buf, exp);
> +      return 1;
> +    }
> +
> +  return 0;
> +}
> +
> +/* This test check append mode initial position (a/a+) based on POSIX defition
> +   (BZ#6544 and BZ#13151) for buffer without null byte end.  */
> +static int
> +do_test_write_append_without_null (const char *mode)
> +{
> +  char buf[] = { 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55 };
> +  char exp[] = { 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55 };
> +
> +  /* If '\0' is not found in buffer, POSIX states that SEEK_SET should be
> +     the size argument.  */
> +  FILE *fp = fmemopen (buf, sizeof (buf) - 2, "a");
> +
> +  fflush (fp);
> +  fputc (0x70, fp);
> +  fseek (fp, 0, SEEK_SET);
> +  fputc (0x70, fp);
> +  fputc (0x70, fp);
> +  fclose (fp);
> +
> +  /* POSIX also states that a write operation on the stream shall not advance
> +     the current buffer size beyond the size given in fmemopen, so the string
> +     should be same.  */
> +  if (memcmp (buf, exp, sizeof (buf)) != 0)
> +    {
> +      printf ("%s: check failed: ", __FUNCTION__);
> +      print_buffer (buf, sizeof (buf));
> +      printf ("!= ");
> +      print_buffer (exp, sizeof (exp));
> +      printf ("\n");
> +      return 1;
> +    }
> +
> +  return 0;
> +}
> +
> +/* This test check for initial position and feek value for fmemopen objects
> +   opened with append mode.  */
> +static int
> +do_test_read_append (void)
> +{
> +  char buf[32] = "testing buffer";
> +  size_t buflen = strlen (buf);
> +  long fpos;
> +
> +  /* POSIX defines for 'a+' the initial position is the first null byte.  */
> +  FILE *fp = fmemopen (buf, sizeof (buf), "a+");
> +
> +  fpos = ftell (fp);
> +  if (fpos != buflen)
> +    {
> +      printf ("%s: ftell|SEEK_SET (fp) %li != strlen (%s) %li\n",
> +	      __FUNCTION__, fpos, buf, buflen);
> +      fclose (fp);
> +      return 1;
> +    }
> +
> +  fseek (fp, 0, SEEK_END);
> +
> +  if (fpos != buflen)
> +    {
> +      printf ("%s: ftell|SEEK_END (fp) %li != strlen (%s) %li\n",
> +	      __FUNCTION__, fpos, buf, buflen);
> +      fclose (fp);
> +      return 1;
> +    }
> +  fclose (fp);
> +
> +  /* Check if attempting to read past the current size, defined as strlen (buf)
> +     yield an EOF.  */
> +  fp = fmemopen (buf, sizeof (buf), "a+");
> +  if (getc(fp) != EOF)
> +    {
> +      printf ("%s: getc(fp) != EOF\n", __FUNCTION__);
> +      fclose (fp);
> +      return -1;
> +    }
> +
> +  fclose (fp);
> +
> +  return 0;
> +}
> +
> +/* This test check for fseek (SEEK_END) using negative offsets (BZ#14292).  The
> +   starting position of descriptor is different base on the opening mode.  */
> +static int
> +do_test_read_seek_neg (const char *mode, const char *expected)
> +{
> +  char buf[] = "abcdefghijklmnopqrstuvxz0123456789";
> +  char tmp[10];
> +  size_t tmps = sizeof (tmps);
> +  long offset = -11;
> +
> +  FILE *fp = fmemopen (buf, sizeof (buf), mode);
> +  fseek (fp, offset, SEEK_END);
> +  fread (tmp, tmps, 1, fp);
> +
> +  if (memcmp (tmp, expected, tmps) != 0)
> +    {
> +      printf ("%s: fmemopen(%s) - fseek (fp, %li, SEEK_END):\n",
> +	      __FUNCTION__, mode, offset);
> +      printf ("  returned: ");
> +      print_buffer (tmp, tmps);
> +      printf ("\n");
> +      printf ("  expected: ");
> +      print_buffer (expected, tmps);
> +      printf ("\n");
> +      return 1;
> +    }
> +
> +  fclose (fp);
> +
> +  return 0;
> +}
> +
> +static int
> +do_test_read_seek_negative (void)
> +{
> +  int ret = 0;
> +
> +  /* 'r' and 'w' modes defines the initial position at the buffer start and
> +     seek with SEEK_END shall seek relative to its size give in fmemopen
> +     call.  The expected tmp result is 0 to 9 *without* the ending null  */
> +  ret += do_test_read_seek_neg ("r", "0123456789");
> +  /* 'a+' mode sets the initial position at the first null byte in buffer and
> +    SEEK_END shall seek relative to its size as well.  The expected result is
> +    z012345678, since SEEK_END plus a+ start at '\0', not size.  */
> +  ret += do_test_read_seek_neg ("a+", "z012345678");
> +
> +  return ret;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  int ret = 0;
> +
> +  ret += do_test_write_append ("a");
> +  ret += do_test_write_append_without_null ("a");
> +  ret += do_test_write_append ("a+");
> +  ret += do_test_write_append_without_null ("a+");
> +
> +  ret += do_test_read_append ();
> +
> +  ret += do_test_read_seek_negative ();
> +
> +  return ret;
> +}
> +
> +#define TEST_FUNCTION do_test ()
> +#include "../test-skeleton.c"
> diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> index aeee312..4273217 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> @@ -2081,3 +2081,6 @@ GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
>   _mcount F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
> diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
> index 980e088..24d6dac 100644
> --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
> @@ -1822,6 +1822,9 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.2
>   GLIBC_2.2 A
>   _IO_adjust_wcolumn F
> diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
> index ce45208..7d54e8c 100644
> --- a/sysdeps/unix/sysv/linux/arm/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
> @@ -89,6 +89,9 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.4
>   GLIBC_2.4 A
>   _Exit F
> diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
> index 58407fc..84e0070 100644
> --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
> @@ -95,6 +95,9 @@ GLIBC_2.18
>  GLIBC_2.19
>   GLIBC_2.19 A
>   fanotify_mark F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.2
>   GLIBC_2.2 A
>   _Exit F
> diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
> index 3cb314d..95351c9 100644
> --- a/sysdeps/unix/sysv/linux/i386/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
> @@ -2023,6 +2023,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
> index 067552d..1a0c7cb 100644
> --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
> @@ -1881,6 +1881,9 @@ GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
>   getunwind F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> index f06cc8e..564ae93 100644
> --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> @@ -90,6 +90,9 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.4
>   GLIBC_2.4 A
>   _Exit F
> diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> index 9010ea7..645517f 100644
> --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> @@ -1979,6 +1979,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> index 6e8d993..61e1259 100644
> --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> @@ -2080,3 +2080,6 @@ GLIBC_2.18
>   xencrypt F
>   xprt_register F
>   xprt_unregister F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> index 1c3490c..1890f5d 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> @@ -1951,6 +1951,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> index d8fd823..f935c46 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> @@ -1949,6 +1949,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> index 3e6ed35..b28a3b8 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> @@ -1947,6 +1947,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> index c7e46aa..aa8bd1b 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> @@ -1941,6 +1941,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> index f27b48b..bf29de2 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> @@ -1983,6 +1983,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> index a54382e..1ce8134 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> @@ -1989,6 +1989,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
> index 195b587..32b5d79 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
> @@ -90,6 +90,9 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   _Exit F
> diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> index 0194f0b..01ef87c 100644
> --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> @@ -1984,6 +1984,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> index 807f702..e5021ff 100644
> --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> @@ -1880,6 +1880,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
> index a653292..bffbf9e 100644
> --- a/sysdeps/unix/sysv/linux/sh/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
> @@ -1864,6 +1864,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> index 9defbdf..8a5b126 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> @@ -1975,6 +1975,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> index 35987fa..61bd28d 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> @@ -1908,6 +1908,9 @@ GLIBC_2.2.4
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
> index caf74b8..fcb582f 100644
> --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
> @@ -2091,3 +2091,6 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
> diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
> index 68d975b..3fa13ff 100644
> --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
> @@ -2091,3 +2091,6 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
> diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
> index caf74b8..fcb582f 100644
> --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
> @@ -2091,3 +2091,6 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> index 914b590..530d543 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> @@ -1854,6 +1854,9 @@ GLIBC_2.2.5
>  GLIBC_2.2.6
>   GLIBC_2.2.6 A
>   __nanosleep F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F
>  GLIBC_2.3
>   GLIBC_2.3 A
>   __ctype_b_loc F
> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> index 0f64c8d..744d59e 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> @@ -2089,3 +2089,6 @@ GLIBC_2.17
>  GLIBC_2.18
>   GLIBC_2.18 A
>   __cxa_thread_atexit_impl F
> +GLIBC_2.21
> + GLIBC_2.21 A
> + fmemopen F

Patch
diff mbox

diff --git a/NEWS b/NEWS
index 1b08d40..bd467e7 100644
--- a/NEWS
+++ b/NEWS
@@ -9,12 +9,12 @@  Version 2.21
 
 * The following bugs are resolved with this release:
 
-  6652, 12926, 13862, 14132, 14138, 14171, 14498, 15215, 15884, 16469,
-  16619, 16740, 16857, 17192, 17266, 17344, 17363, 17370, 17371, 17411,
-  17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, 17571,
-  17572, 17573, 17574, 17581, 17582, 17583, 17584, 17585, 17589, 17594,
-  17601, 17608, 17616, 17625, 17633, 17647, 17653, 17664, 17665, 17668,
-  17682.
+  6544, 6652, 11216, 12836, 12926, 13151, 13152, 13862, 14132, 14138, 
+  14171, 14292, 14498, 15215, 15884, 16469, 16619, 16740, 16857, 17192,
+  17266, 17344, 17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501,
+  17506, 17508, 17522, 17555, 17570, 17571, 17572, 17573, 17574, 17581,
+  17582, 17583, 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625,
+  17633, 17647, 17653, 17664, 17665, 17668, 17682.
 
 * CVE-2104-7817 The wordexp function could ignore the WRDE_NOCMD flag
   under certain input conditions resulting in the execution of a shell for
diff --git a/include/stdio.h b/include/stdio.h
index 0010607..e480701 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -158,7 +158,6 @@  libc_hidden_proto (fgets_unlocked)
 extern __typeof (fgets_unlocked) __fgets_unlocked;
 libc_hidden_proto (__fgets_unlocked)
 libc_hidden_proto (fputs_unlocked)
-libc_hidden_proto (fmemopen)
 libc_hidden_proto (open_memstream)
 libc_hidden_proto (__libc_fatal)
 libc_hidden_proto (__vsprintf_chk)
@@ -186,6 +185,9 @@  gets (char *__str)
 }
 #  endif
 
+extern FILE * __fmemopen (void *buf, size_t len, const char *mode);
+libc_hidden_proto (__fmemopen)
+
 __END_DECLS
 # endif
 
diff --git a/libio/Makefile b/libio/Makefile
index 2742128..c1dec9a 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -46,7 +46,7 @@  routines	:=							      \
 	__fbufsize __freading __fwriting __freadable __fwritable __flbf	      \
 	__fpurge __fpending __fsetlocking				      \
 									      \
-	libc_fatal fmemopen
+	libc_fatal fmemopen oldfmemopen
 
 tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc   \
 	tst_wprintf2 tst-widetext test-fmemopen tst-ext tst-ext2 \
diff --git a/libio/Versions b/libio/Versions
index 8df89d2..8102da0 100644
--- a/libio/Versions
+++ b/libio/Versions
@@ -148,6 +148,10 @@  libc {
   GLIBC_2.4 {
     open_wmemstream;
   }
+  GLIBC_2.21 {
+    # f*
+    fmemopen;
+  }
   GLIBC_PRIVATE {
     # Used by NPTL and librt
     __libc_fatal;
diff --git a/libio/fmemopen.c b/libio/fmemopen.c
index aee2696..20b646c 100644
--- a/libio/fmemopen.c
+++ b/libio/fmemopen.c
@@ -1,7 +1,6 @@ 
-/* Fmemopen implementation.
-   Copyright (C) 2000-2014 Free Software Foundation, Inc.
+/* fmemopen implementation.
+   Copyright (C) 2014 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
-   Contributed by Hanno Mueller, kontakt@hanno.de, 2000.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -17,54 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-/*
- * fmemopen() - "my" version of a string stream
- * Hanno Mueller, kontakt@hanno.de
- *
- *
- * I needed fmemopen() for an application that I currently work on,
- * but couldn't find it in libio. The following snippet of code is an
- * attempt to implement what glibc's documentation describes.
- *
- *
- *
- * I already see some potential problems:
- *
- * - I never used the "original" fmemopen(). I am sure that "my"
- *   fmemopen() behaves differently than the original version.
- *
- * - The documentation doesn't say wether a string stream allows
- *   seeks. I checked the old fmemopen implementation in glibc's stdio
- *   directory, wasn't quite able to see what is going on in that
- *   source, but as far as I understand there was no seek there. For
- *   my application, I needed fseek() and ftell(), so it's here.
- *
- * - "append" mode and fseek(p, SEEK_END) have two different ideas
- *   about the "end" of the stream.
- *
- *   As described in the documentation, when opening the file in
- *   "append" mode, the position pointer will be set to the first null
- *   character of the string buffer (yet the buffer may already
- *   contain more data). For fseek(), the last byte of the buffer is
- *   used as the end of the stream.
- *
- * - It is unclear to me what the documentation tries to say when it
- *   explains what happens when you use fmemopen with a NULL
- *   buffer.
- *
- *   Quote: "fmemopen [then] allocates an array SIZE bytes long. This
- *   is really only useful if you are going to write things to the
- *   buffer and then read them back in again."
- *
- *   What does that mean if the original fmemopen() did not allow
- *   seeking? How do you read what you just wrote without seeking back
- *   to the beginning of the stream?
- *
- * - I think there should be a second version of fmemopen() that does
- *   not add null characters for each write. (At least in my
- *   application, I am not actually using strings but binary data and
- *   so I don't need the stream to add null characters on its own.)
- */
+/* fmemopen() from 2.21 and forward works as defined by POSIX.  It also
+   provides an older symbol, version 2.2.5, that behaves different regarding
+   SEEK_END (libio/oldfmemopen.c).  */
+
 
 #include <errno.h>
 #include <libio.h>
@@ -79,25 +34,23 @@ 
 typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
 struct fmemopen_cookie_struct
 {
-  char *buffer;
-  int mybuffer;
-  int binmode;
-  size_t size;
-  _IO_off64_t pos;
-  size_t maxpos;
+  char        *buffer;   /* memory buffer.  */
+  int         mybuffer;  /* own allocated buffer?  */
+  int         append;    /* buffer openened for append?  */
+  size_t      size;      /* buffer length in bytes.  */
+  _IO_off64_t pos;       /* current position at the buffer.  */
+  size_t      maxpos;    /* max position in buffer.  */
 };
 
 
 static ssize_t
 fmemopen_read (void *cookie, char *b, size_t s)
 {
-  fmemopen_cookie_t *c;
-
-  c = (fmemopen_cookie_t *) cookie;
+  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
 
-  if (c->pos + s > c->size)
+  if (c->pos + s > c->maxpos)
     {
-      if ((size_t) c->pos == c->size)
+      if ((size_t) c->pos == c->maxpos)
 	return 0;
       s = c->size - c->pos;
     }
@@ -115,29 +68,28 @@  fmemopen_read (void *cookie, char *b, size_t s)
 static ssize_t
 fmemopen_write (void *cookie, const char *b, size_t s)
 {
-  fmemopen_cookie_t *c;
+  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;;
+  _IO_off64_t pos = c->append ? c->maxpos : c->pos;
   int addnullc;
 
-  c = (fmemopen_cookie_t *) cookie;
-
-  addnullc = c->binmode == 0 && (s == 0 || b[s - 1] != '\0');
+  addnullc = (s == 0 || b[s - 1] != '\0');
 
-  if (c->pos + s + addnullc > c->size)
+  if (pos + s + addnullc > c->size)
     {
-      if ((size_t) (c->pos + addnullc) == c->size)
+      if ((size_t) (pos + addnullc) >= c->size)
 	{
 	  __set_errno (ENOSPC);
 	  return 0;
 	}
-      s = c->size - c->pos - addnullc;
+      s = c->size - pos - addnullc;
     }
 
-  memcpy (&(c->buffer[c->pos]), b, s);
+  memcpy (&(c->buffer[pos]), b, s);
 
-  c->pos += s;
-  if ((size_t) c->pos > c->maxpos)
+  pos += s;
+  if ((size_t) pos > c->maxpos)
     {
-      c->maxpos = c->pos;
+      c->maxpos = pos;
       if (addnullc)
 	c->buffer[c->maxpos] = '\0';
     }
@@ -150,9 +102,7 @@  static int
 fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
 {
   _IO_off64_t np;
-  fmemopen_cookie_t *c;
-
-  c = (fmemopen_cookie_t *) cookie;
+  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
 
   switch (w)
     {
@@ -165,7 +115,7 @@  fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
       break;
 
     case SEEK_END:
-      np = (c->binmode ? c->size : c->maxpos) - *p;
+      np = c->maxpos + *p;
       break;
 
     default:
@@ -184,9 +134,7 @@  fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
 static int
 fmemopen_close (void *cookie)
 {
-  fmemopen_cookie_t *c;
-
-  c = (fmemopen_cookie_t *) cookie;
+  fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
 
   if (c->mybuffer)
     free (c->buffer);
@@ -197,18 +145,11 @@  fmemopen_close (void *cookie)
 
 
 FILE *
-fmemopen (void *buf, size_t len, const char *mode)
+__fmemopen (void *buf, size_t len, const char *mode)
 {
   cookie_io_functions_t iof;
   fmemopen_cookie_t *c;
 
-  if (__glibc_unlikely (len == 0))
-    {
-    einval:
-      __set_errno (EINVAL);
-      return NULL;
-    }
-
   c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
   if (c == NULL)
     return NULL;
@@ -231,26 +172,38 @@  fmemopen (void *buf, size_t len, const char *mode)
       if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
 	{
 	  free (c);
-	  goto einval;
+	  __set_errno (EINVAL);
+	  return NULL;
 	}
 
       c->buffer = buf;
 
-      if (mode[0] == 'w')
+      /* POSIX states that w+ mode should truncate the buffer.  */
+      if (mode[0] == 'w' && mode[1] == '+')
 	c->buffer[0] = '\0';
 
       c->maxpos = strnlen (c->buffer, len);
     }
 
+
+  /* Mode   |  starting position (cookie::pos) |          size (cookie::size)
+   * ------ |----------------------------------|-----------------------------
+   * read   |          beginning of the buffer |                size argument
+   * write  |          beginning of the buffer |                         zero
+   * append |    first null or size buffer + 1 |  first null or size argument
+   */
+
   c->size = len;
 
-  if (mode[0] == 'a')
+  if (mode[0] == 'r')
+    c->maxpos = len;
+
+  c->append = mode[0] == 'a';
+  if (c->append)
     c->pos = c->maxpos;
   else
     c->pos = 0;
 
-  c->binmode = mode[0] != '\0' && mode[1] == 'b';
-
   iof.read = fmemopen_read;
   iof.write = fmemopen_write;
   iof.seek = fmemopen_seek;
@@ -258,4 +211,5 @@  fmemopen (void *buf, size_t len, const char *mode)
 
   return _IO_fopencookie (c, mode, iof);
 }
-libc_hidden_def (fmemopen)
+libc_hidden_def (__fmemopen)
+versioned_symbol (libc, __fmemopen, fmemopen, GLIBC_2_21);
diff --git a/libio/oldfmemopen.c b/libio/oldfmemopen.c
new file mode 100644
index 0000000..88f8473
--- /dev/null
+++ b/libio/oldfmemopen.c
@@ -0,0 +1,265 @@ 
+/* Fmemopen implementation.
+   Copyright (C) 2000-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Hanno Mueller, kontakt@hanno.de, 2000.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/*
+ * fmemopen() - "my" version of a string stream
+ * Hanno Mueller, kontakt@hanno.de
+ *
+ *
+ * I needed fmemopen() for an application that I currently work on,
+ * but couldn't find it in libio. The following snippet of code is an
+ * attempt to implement what glibc's documentation describes.
+ *
+ *
+ *
+ * I already see some potential problems:
+ *
+ * - I never used the "original" fmemopen(). I am sure that "my"
+ *   fmemopen() behaves differently than the original version.
+ *
+ * - The documentation doesn't say wether a string stream allows
+ *   seeks. I checked the old fmemopen implementation in glibc's stdio
+ *   directory, wasn't quite able to see what is going on in that
+ *   source, but as far as I understand there was no seek there. For
+ *   my application, I needed fseek() and ftell(), so it's here.
+ *
+ * - "append" mode and fseek(p, SEEK_END) have two different ideas
+ *   about the "end" of the stream.
+ *
+ *   As described in the documentation, when opening the file in
+ *   "append" mode, the position pointer will be set to the first null
+ *   character of the string buffer (yet the buffer may already
+ *   contain more data). For fseek(), the last byte of the buffer is
+ *   used as the end of the stream.
+ *
+ * - It is unclear to me what the documentation tries to say when it
+ *   explains what happens when you use fmemopen with a NULL
+ *   buffer.
+ *
+ *   Quote: "fmemopen [then] allocates an array SIZE bytes long. This
+ *   is really only useful if you are going to write things to the
+ *   buffer and then read them back in again."
+ *
+ *   What does that mean if the original fmemopen() did not allow
+ *   seeking? How do you read what you just wrote without seeking back
+ *   to the beginning of the stream?
+ *
+ * - I think there should be a second version of fmemopen() that does
+ *   not add null characters for each write. (At least in my
+ *   application, I am not actually using strings but binary data and
+ *   so I don't need the stream to add null characters on its own.)
+ */
+
+#include "libioP.h"
+
+#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_21)
+
+#include <errno.h>
+#include <libio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+
+
+typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
+struct fmemopen_cookie_struct
+{
+  char *buffer;
+  int mybuffer;
+  int binmode;
+  size_t size;
+  _IO_off64_t pos;
+  size_t maxpos;
+};
+
+
+static ssize_t
+fmemopen_read (void *cookie, char *b, size_t s)
+{
+  fmemopen_cookie_t *c;
+
+  c = (fmemopen_cookie_t *) cookie;
+
+  if (c->pos + s > c->size)
+    {
+      if ((size_t) c->pos == c->size)
+	return 0;
+      s = c->size - c->pos;
+    }
+
+  memcpy (b, &(c->buffer[c->pos]), s);
+
+  c->pos += s;
+  if ((size_t) c->pos > c->maxpos)
+    c->maxpos = c->pos;
+
+  return s;
+}
+
+
+static ssize_t
+fmemopen_write (void *cookie, const char *b, size_t s)
+{
+  fmemopen_cookie_t *c;
+  int addnullc;
+
+  c = (fmemopen_cookie_t *) cookie;
+
+  addnullc = c->binmode == 0 && (s == 0 || b[s - 1] != '\0');
+
+  if (c->pos + s + addnullc > c->size)
+    {
+      if ((size_t) (c->pos + addnullc) == c->size)
+	{
+	  __set_errno (ENOSPC);
+	  return 0;
+	}
+      s = c->size - c->pos - addnullc;
+    }
+
+  memcpy (&(c->buffer[c->pos]), b, s);
+
+  c->pos += s;
+  if ((size_t) c->pos > c->maxpos)
+    {
+      c->maxpos = c->pos;
+      if (addnullc)
+	c->buffer[c->maxpos] = '\0';
+    }
+
+  return s;
+}
+
+
+static int
+fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
+{
+  _IO_off64_t np;
+  fmemopen_cookie_t *c;
+
+  c = (fmemopen_cookie_t *) cookie;
+
+  switch (w)
+    {
+    case SEEK_SET:
+      np = *p;
+      break;
+
+    case SEEK_CUR:
+      np = c->pos + *p;
+      break;
+
+    case SEEK_END:
+      np = (c->binmode ? c->size : c->maxpos) - *p;
+      break;
+
+    default:
+      return -1;
+    }
+
+  if (np < 0 || (size_t) np > c->size)
+    return -1;
+
+  *p = c->pos = np;
+
+  return 0;
+}
+
+
+static int
+fmemopen_close (void *cookie)
+{
+  fmemopen_cookie_t *c;
+
+  c = (fmemopen_cookie_t *) cookie;
+
+  if (c->mybuffer)
+    free (c->buffer);
+  free (c);
+
+  return 0;
+}
+
+
+FILE *
+__old_fmemopen (void *buf, size_t len, const char *mode)
+{
+  cookie_io_functions_t iof;
+  fmemopen_cookie_t *c;
+
+  if (__glibc_unlikely (len == 0))
+    {
+    einval:
+      __set_errno (EINVAL);
+      return NULL;
+    }
+
+  c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
+  if (c == NULL)
+    return NULL;
+
+  c->mybuffer = (buf == NULL);
+
+  if (c->mybuffer)
+    {
+      c->buffer = (char *) malloc (len);
+      if (c->buffer == NULL)
+	{
+	  free (c);
+	  return NULL;
+	}
+      c->buffer[0] = '\0';
+      c->maxpos = 0;
+    }
+  else
+    {
+      if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
+	{
+	  free (c);
+	  goto einval;
+	}
+
+      c->buffer = buf;
+
+      if (mode[0] == 'w')
+	c->buffer[0] = '\0';
+
+      c->maxpos = strnlen (c->buffer, len);
+    }
+
+  c->size = len;
+
+  if (mode[0] == 'a')
+    c->pos = c->maxpos;
+  else
+    c->pos = 0;
+
+  c->binmode = mode[0] != '\0' && mode[1] == 'b';
+
+  iof.read = fmemopen_read;
+  iof.write = fmemopen_write;
+  iof.seek = fmemopen_seek;
+  iof.close = fmemopen_close;
+
+  return _IO_fopencookie (c, mode, iof);
+}
+compat_symbol (libc, __old_fmemopen, fmemopen, GLIBC_2_2);
+#endif
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 5f8e534..5971e65 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -57,7 +57,7 @@  tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
 	 bug19 bug19a tst-popen2 scanf13 scanf14 scanf15 bug20 bug21 bug22 \
 	 scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \
 	 bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3 \
-	 bug25 tst-printf-round bug26
+	 bug25 tst-printf-round bug26 tst-fmemopen3
 
 test-srcs = tst-unbputc tst-printf
 
diff --git a/stdio-common/psiginfo.c b/stdio-common/psiginfo.c
index 564d237..62a9671 100644
--- a/stdio-common/psiginfo.c
+++ b/stdio-common/psiginfo.c
@@ -60,7 +60,7 @@  void
 psiginfo (const siginfo_t *pinfo, const char *s)
 {
   char buf[512];
-  FILE *fp = fmemopen (buf, sizeof (buf), "w");
+  FILE *fp = __fmemopen (buf, sizeof (buf), "w");
   if (fp == NULL)
     {
       const char *colon;
diff --git a/stdio-common/tst-fmemopen3.c b/stdio-common/tst-fmemopen3.c
new file mode 100644
index 0000000..8cd211f
--- /dev/null
+++ b/stdio-common/tst-fmemopen3.c
@@ -0,0 +1,206 @@ 
+/* fmemopen tests for append and read mode.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+
+static void
+print_buffer (const char *s, size_t n)
+{
+  size_t i;
+  for (i=0; i<n; ++i)
+    printf ("0x%02X (%c), ", s[i], s[i]);
+}
+
+/* This test check append mode initial position (a/a+) based on POSIX defition
+   (BZ#6544 and BZ#13151).  */
+static int
+do_test_write_append (const char *mode)
+{
+  char buf[32] = "testing buffer";
+  char exp[32] = "testing bufferXX";
+
+  FILE *fp = fmemopen (buf, sizeof (buf), mode);
+
+  fflush (fp);
+  fprintf (fp, "X");
+  fseek (fp, 0, SEEK_SET);
+  fprintf (fp, "X");
+  fclose (fp);
+
+  if (strcmp (buf, exp) != 0)
+    {
+      printf ("%s: check failed: %s != %s\n", __FUNCTION__, buf, exp);
+      return 1;
+    }
+
+  return 0;
+}
+
+/* This test check append mode initial position (a/a+) based on POSIX defition
+   (BZ#6544 and BZ#13151) for buffer without null byte end.  */
+static int
+do_test_write_append_without_null (const char *mode)
+{
+  char buf[] = { 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55 };
+  char exp[] = { 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55 };
+
+  /* If '\0' is not found in buffer, POSIX states that SEEK_SET should be
+     the size argument.  */
+  FILE *fp = fmemopen (buf, sizeof (buf) - 2, "a");
+
+  fflush (fp);
+  fputc (0x70, fp);
+  fseek (fp, 0, SEEK_SET);
+  fputc (0x70, fp);
+  fputc (0x70, fp);
+  fclose (fp);
+
+  /* POSIX also states that a write operation on the stream shall not advance
+     the current buffer size beyond the size given in fmemopen, so the string
+     should be same.  */
+  if (memcmp (buf, exp, sizeof (buf)) != 0)
+    {
+      printf ("%s: check failed: ", __FUNCTION__);
+      print_buffer (buf, sizeof (buf));
+      printf ("!= ");
+      print_buffer (exp, sizeof (exp));
+      printf ("\n");
+      return 1;
+    }
+
+  return 0;
+}
+
+/* This test check for initial position and feek value for fmemopen objects
+   opened with append mode.  */
+static int
+do_test_read_append (void)
+{
+  char buf[32] = "testing buffer";
+  size_t buflen = strlen (buf);
+  long fpos;
+
+  /* POSIX defines for 'a+' the initial position is the first null byte.  */
+  FILE *fp = fmemopen (buf, sizeof (buf), "a+");
+
+  fpos = ftell (fp);
+  if (fpos != buflen)
+    {
+      printf ("%s: ftell|SEEK_SET (fp) %li != strlen (%s) %li\n",
+	      __FUNCTION__, fpos, buf, buflen);
+      fclose (fp);
+      return 1;
+    }
+
+  fseek (fp, 0, SEEK_END);
+
+  if (fpos != buflen)
+    {
+      printf ("%s: ftell|SEEK_END (fp) %li != strlen (%s) %li\n",
+	      __FUNCTION__, fpos, buf, buflen);
+      fclose (fp);
+      return 1;
+    }
+  fclose (fp);
+
+  /* Check if attempting to read past the current size, defined as strlen (buf)
+     yield an EOF.  */
+  fp = fmemopen (buf, sizeof (buf), "a+");
+  if (getc(fp) != EOF)
+    {
+      printf ("%s: getc(fp) != EOF\n", __FUNCTION__);
+      fclose (fp);
+      return -1;
+    }
+
+  fclose (fp);
+
+  return 0;
+}
+
+/* This test check for fseek (SEEK_END) using negative offsets (BZ#14292).  The
+   starting position of descriptor is different base on the opening mode.  */
+static int
+do_test_read_seek_neg (const char *mode, const char *expected)
+{
+  char buf[] = "abcdefghijklmnopqrstuvxz0123456789";
+  char tmp[10];
+  size_t tmps = sizeof (tmps);
+  long offset = -11;
+
+  FILE *fp = fmemopen (buf, sizeof (buf), mode);
+  fseek (fp, offset, SEEK_END);
+  fread (tmp, tmps, 1, fp);
+
+  if (memcmp (tmp, expected, tmps) != 0)
+    {
+      printf ("%s: fmemopen(%s) - fseek (fp, %li, SEEK_END):\n",
+	      __FUNCTION__, mode, offset);
+      printf ("  returned: ");
+      print_buffer (tmp, tmps);
+      printf ("\n");
+      printf ("  expected: ");
+      print_buffer (expected, tmps);
+      printf ("\n");
+      return 1;
+    }
+
+  fclose (fp);
+
+  return 0;
+}
+
+static int
+do_test_read_seek_negative (void)
+{
+  int ret = 0;
+
+  /* 'r' and 'w' modes defines the initial position at the buffer start and
+     seek with SEEK_END shall seek relative to its size give in fmemopen
+     call.  The expected tmp result is 0 to 9 *without* the ending null  */
+  ret += do_test_read_seek_neg ("r", "0123456789");
+  /* 'a+' mode sets the initial position at the first null byte in buffer and
+    SEEK_END shall seek relative to its size as well.  The expected result is
+    z012345678, since SEEK_END plus a+ start at '\0', not size.  */
+  ret += do_test_read_seek_neg ("a+", "z012345678");
+
+  return ret;
+}
+
+static int
+do_test (void)
+{
+  int ret = 0;
+
+  ret += do_test_write_append ("a");
+  ret += do_test_write_append_without_null ("a");
+  ret += do_test_write_append ("a+");
+  ret += do_test_write_append_without_null ("a+");
+
+  ret += do_test_read_append ();
+
+  ret += do_test_read_seek_negative ();
+
+  return ret;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index aeee312..4273217 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2081,3 +2081,6 @@  GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
  _mcount F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 980e088..24d6dac 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -1822,6 +1822,9 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.2
  GLIBC_2.2 A
  _IO_adjust_wcolumn F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index ce45208..7d54e8c 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -89,6 +89,9 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.4
  GLIBC_2.4 A
  _Exit F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 58407fc..84e0070 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -95,6 +95,9 @@  GLIBC_2.18
 GLIBC_2.19
  GLIBC_2.19 A
  fanotify_mark F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.2
  GLIBC_2.2 A
  _Exit F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 3cb314d..95351c9 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2023,6 +2023,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 067552d..1a0c7cb 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -1881,6 +1881,9 @@  GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
  getunwind F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index f06cc8e..564ae93 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -90,6 +90,9 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.4
  GLIBC_2.4 A
  _Exit F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index 9010ea7..645517f 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -1979,6 +1979,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
index 6e8d993..61e1259 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2080,3 +2080,6 @@  GLIBC_2.18
  xencrypt F
  xprt_register F
  xprt_unregister F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 1c3490c..1890f5d 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -1951,6 +1951,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index d8fd823..f935c46 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -1949,6 +1949,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 3e6ed35..b28a3b8 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -1947,6 +1947,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index c7e46aa..aa8bd1b 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -1941,6 +1941,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index f27b48b..bf29de2 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -1983,6 +1983,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index a54382e..1ce8134 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -1989,6 +1989,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
index 195b587..32b5d79 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
@@ -90,6 +90,9 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  _Exit F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index 0194f0b..01ef87c 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -1984,6 +1984,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index 807f702..e5021ff 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -1880,6 +1880,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
index a653292..bffbf9e 100644
--- a/sysdeps/unix/sysv/linux/sh/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
@@ -1864,6 +1864,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 9defbdf..8a5b126 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -1975,6 +1975,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index 35987fa..61bd28d 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -1908,6 +1908,9 @@  GLIBC_2.2.4
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
index caf74b8..fcb582f 100644
--- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
@@ -2091,3 +2091,6 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
index 68d975b..3fa13ff 100644
--- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
@@ -2091,3 +2091,6 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
index caf74b8..fcb582f 100644
--- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
@@ -2091,3 +2091,6 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 914b590..530d543 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -1854,6 +1854,9 @@  GLIBC_2.2.5
 GLIBC_2.2.6
  GLIBC_2.2.6 A
  __nanosleep F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F
 GLIBC_2.3
  GLIBC_2.3 A
  __ctype_b_loc F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 0f64c8d..744d59e 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2089,3 +2089,6 @@  GLIBC_2.17
 GLIBC_2.18
  GLIBC_2.18 A
  __cxa_thread_atexit_impl F
+GLIBC_2.21
+ GLIBC_2.21 A
+ fmemopen F