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libio: fmemopen rewrite to POSIX compliance
This patch added a new fmemopen version, for glibc 2.22, 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). * include/stdio.h (fmemopen): Remove hidden prototype. (__fmemopen): Add new hidden prototype. * libio/Makefile: Add oldfmemopen object. * libio/Versions [GLIBC_2.22]: 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_2.22]: Add fmemopen. * sysdeps/unix/sysv/linux/alpha/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/i386/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/ia64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/microblaze/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/sh/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/hppa/libc.abilist [GLIBC_2.22]: Likewise. * sysdeps/unix/sysv/linux/nios2/libc.abilist [GLIBC_2.22]: Likewise.
This commit is contained in:
Adhemerval Zanella
committed by
Adhemerval Zanella
Adhemerval Zanella
parent
1c1e312520
commit
fdb7d390dd
140
libio/fmemopen.c
140
libio/fmemopen.c
@ -1,7 +1,6 @@
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/* Fmemopen implementation.
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Copyright (C) 2000-2015 Free Software Foundation, Inc.
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/* fmemopen implementation.
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Copyright (C) 2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Hanno Mueller, kontakt@hanno.de, 2000.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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@ -17,54 +16,10 @@
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/*
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* fmemopen() - "my" version of a string stream
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* Hanno Mueller, kontakt@hanno.de
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*
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*
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* I needed fmemopen() for an application that I currently work on,
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* but couldn't find it in libio. The following snippet of code is an
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* attempt to implement what glibc's documentation describes.
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*
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*
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*
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* I already see some potential problems:
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*
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* - I never used the "original" fmemopen(). I am sure that "my"
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* fmemopen() behaves differently than the original version.
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*
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* - The documentation doesn't say wether a string stream allows
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* seeks. I checked the old fmemopen implementation in glibc's stdio
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* directory, wasn't quite able to see what is going on in that
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* source, but as far as I understand there was no seek there. For
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* my application, I needed fseek() and ftell(), so it's here.
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*
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* - "append" mode and fseek(p, SEEK_END) have two different ideas
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* about the "end" of the stream.
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*
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* As described in the documentation, when opening the file in
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* "append" mode, the position pointer will be set to the first null
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* character of the string buffer (yet the buffer may already
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* contain more data). For fseek(), the last byte of the buffer is
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* used as the end of the stream.
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*
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* - It is unclear to me what the documentation tries to say when it
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* explains what happens when you use fmemopen with a NULL
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* buffer.
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*
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* Quote: "fmemopen [then] allocates an array SIZE bytes long. This
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* is really only useful if you are going to write things to the
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* buffer and then read them back in again."
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*
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* What does that mean if the original fmemopen() did not allow
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* seeking? How do you read what you just wrote without seeking back
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* to the beginning of the stream?
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*
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* - I think there should be a second version of fmemopen() that does
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* not add null characters for each write. (At least in my
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* application, I am not actually using strings but binary data and
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* so I don't need the stream to add null characters on its own.)
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*/
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/* fmemopen() from 2.22 and forward works as defined by POSIX. It also
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provides an older symbol, version 2.2.5, that behaves different regarding
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SEEK_END (libio/oldfmemopen.c). */
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#include <errno.h>
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#include <libio.h>
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@ -79,25 +34,23 @@
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typedef struct fmemopen_cookie_struct fmemopen_cookie_t;
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struct fmemopen_cookie_struct
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{
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char *buffer;
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int mybuffer;
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int binmode;
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size_t size;
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_IO_off64_t pos;
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size_t maxpos;
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char *buffer; /* memory buffer. */
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int mybuffer; /* allocated my buffer? */
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int append; /* buffer open for append? */
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size_t size; /* buffer length in bytes. */
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_IO_off64_t pos; /* current position at the buffer. */
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size_t maxpos; /* max position in buffer. */
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};
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static ssize_t
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fmemopen_read (void *cookie, char *b, size_t s)
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{
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fmemopen_cookie_t *c;
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fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
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c = (fmemopen_cookie_t *) cookie;
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if (c->pos + s > c->size)
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if (c->pos + s > c->maxpos)
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{
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if ((size_t) c->pos == c->size)
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if ((size_t) c->pos == c->maxpos)
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return 0;
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s = c->size - c->pos;
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}
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@ -115,29 +68,28 @@ fmemopen_read (void *cookie, char *b, size_t s)
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static ssize_t
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fmemopen_write (void *cookie, const char *b, size_t s)
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{
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fmemopen_cookie_t *c;
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fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;;
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_IO_off64_t pos = c->append ? c->maxpos : c->pos;
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int addnullc;
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c = (fmemopen_cookie_t *) cookie;
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addnullc = (s == 0 || b[s - 1] != '\0');
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addnullc = c->binmode == 0 && (s == 0 || b[s - 1] != '\0');
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if (c->pos + s + addnullc > c->size)
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if (pos + s + addnullc > c->size)
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{
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if ((size_t) (c->pos + addnullc) >= c->size)
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{
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__set_errno (ENOSPC);
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return 0;
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}
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s = c->size - c->pos - addnullc;
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s = c->size - pos - addnullc;
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}
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memcpy (&(c->buffer[c->pos]), b, s);
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memcpy (&(c->buffer[pos]), b, s);
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c->pos += s;
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if ((size_t) c->pos > c->maxpos)
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pos += s;
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if ((size_t) pos > c->maxpos)
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{
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c->maxpos = c->pos;
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c->maxpos = pos;
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if (addnullc)
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c->buffer[c->maxpos] = '\0';
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}
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@ -150,9 +102,7 @@ static int
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fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
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{
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_IO_off64_t np;
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fmemopen_cookie_t *c;
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c = (fmemopen_cookie_t *) cookie;
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fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
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switch (w)
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{
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@ -165,7 +115,7 @@ fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
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break;
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case SEEK_END:
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np = (c->binmode ? c->size : c->maxpos) - *p;
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np = c->maxpos + *p;
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break;
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default:
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@ -184,9 +134,7 @@ fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
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static int
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fmemopen_close (void *cookie)
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{
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fmemopen_cookie_t *c;
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c = (fmemopen_cookie_t *) cookie;
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fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;
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if (c->mybuffer)
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free (c->buffer);
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@ -197,18 +145,11 @@ fmemopen_close (void *cookie)
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FILE *
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fmemopen (void *buf, size_t len, const char *mode)
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__fmemopen (void *buf, size_t len, const char *mode)
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{
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cookie_io_functions_t iof;
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fmemopen_cookie_t *c;
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if (__glibc_unlikely (len == 0))
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{
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einval:
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__set_errno (EINVAL);
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return NULL;
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}
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c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
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if (c == NULL)
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return NULL;
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@ -231,26 +172,38 @@ fmemopen (void *buf, size_t len, const char *mode)
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if (__glibc_unlikely ((uintptr_t) len > -(uintptr_t) buf))
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{
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free (c);
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goto einval;
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__set_errno (EINVAL);
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return NULL;
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}
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c->buffer = buf;
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if (mode[0] == 'w')
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/* POSIX states that w+ mode should truncate the buffer. */
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if (mode[0] == 'w' && mode[1] == '+')
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c->buffer[0] = '\0';
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c->maxpos = strnlen (c->buffer, len);
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}
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/* Mode | starting position (cookie::pos) | size (cookie::size)
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------ |----------------------------------|-----------------------------
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read | beginning of the buffer | size argument
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write | beginning of the buffer | zero
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append | first null or size buffer + 1 | first null or size argument
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*/
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c->size = len;
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if (mode[0] == 'a')
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if (mode[0] == 'r')
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c->maxpos = len;
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c->append = mode[0] == 'a';
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if (c->append)
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c->pos = c->maxpos;
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else
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c->pos = 0;
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c->binmode = mode[0] != '\0' && mode[1] == 'b';
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iof.read = fmemopen_read;
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iof.write = fmemopen_write;
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iof.seek = fmemopen_seek;
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@ -258,4 +211,5 @@ fmemopen (void *buf, size_t len, const char *mode)
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return _IO_fopencookie (c, mode, iof);
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}
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libc_hidden_def (fmemopen)
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libc_hidden_def (__fmemopen)
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versioned_symbol (libc, __fmemopen, fmemopen, GLIBC_2_22);
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