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Simplify fseek/ftell. 

Another step towards _FILE_OFFSET_BITS=64 support.

Bug: http://b/24807045
Change-Id: I00b83c81a7b108176c4d9437bc32611f73b7e967
This commit is contained in:
Elliott Hughes 2016-01-20 17:14:53 -08:00
parent 5f1ff279ea
commit 2704bd1340
7 changed files with 192 additions and 425 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
libc/Android.mk
View File

@ -464,9 +464,7 @@ libc_upstream_openbsd_ndk_src_files := \
upstream-openbsd/lib/libc/stdio/fputws.c \
upstream-openbsd/lib/libc/stdio/freopen.c \
upstream-openbsd/lib/libc/stdio/fscanf.c \
upstream-openbsd/lib/libc/stdio/fseek.c \
upstream-openbsd/lib/libc/stdio/fsetpos.c \
upstream-openbsd/lib/libc/stdio/ftell.c \
upstream-openbsd/lib/libc/stdio/funopen.c \
upstream-openbsd/lib/libc/stdio/fvwrite.c \
upstream-openbsd/lib/libc/stdio/fwalk.c \

6
libc/include/stdio.h
View File

@ -73,9 +73,9 @@ extern FILE* stderr;
#define __SMBF 0x0080 /* _buf is from malloc */
#define __SAPP 0x0100 /* fdopen()ed in append mode */
#define __SSTR 0x0200 /* this is an sprintf/snprintf string */
#define __SOPT 0x0400 /* do fseek() optimization */
#define __SNPT 0x0800 /* do not do fseek() optimization */
#define __SOFF 0x1000 /* set iff _offset is in fact correct */
/* #define __SOPT 0x0400 --- historical (do fseek() optimization). */
/* #define __SNPT 0x0800 --- historical (do not do fseek() optimization). */
/* #define __SOFF 0x1000 --- historical (set iff _offset is in fact correct). */
#define __SMOD 0x2000 /* true => fgetln modified _p text */
#define __SALC 0x4000 /* allocate string space dynamically */
#define __SIGN 0x8000 /* ignore this file in _fwalk */

5
libc/stdio/local.h
View File

@ -92,7 +92,6 @@ struct __sFILE {
/* Unix stdio files get aligned to block boundaries on fseek() */
int _blksize; /* stat.st_blksize (may be != _bf._size) */
fpos_t _offset; /* current lseek offset */
};
/*
@ -112,6 +111,10 @@ struct __sfileext {
bool _caller_handles_locking;
};
// TODO: remove remaining references to these obsolete flags.
#define __SNPT 0
#define __SOPT 0
#if defined(__cplusplus)
#define _EXT(fp) reinterpret_cast<__sfileext*>((fp)->_ext._base)
#else

232
libc/stdio/stdio.cpp
View File

@ -35,6 +35,7 @@
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
@ -51,7 +52,7 @@
#define std(flags, file) \
{0,0,0,flags,file,{0,0},0,__sF+file,__sclose,__sread,__sseek,__swrite, \
{(unsigned char *)(__sFext+file), 0},NULL,0,{0},{0},{0,0},0,0}
{(unsigned char *)(__sFext+file), 0},NULL,0,{0},{0},{0,0},0}
_THREAD_PRIVATE_MUTEX(__sfp_mutex);
@ -85,25 +86,38 @@ FILE* stderr = &__sF[2];
struct glue __sglue = { NULL, 3, __sF };
static struct glue* lastglue = &__sglue;
class ScopedFileLock {
public:
ScopedFileLock(FILE* fp) : fp_(fp) {
FLOCKFILE(fp_);
}
~ScopedFileLock() {
FUNLOCKFILE(fp_);
}
private:
FILE* fp_;
};
static glue* moreglue(int n) {
static FILE empty;
static FILE empty;
char* data = new char[sizeof(glue) + ALIGNBYTES + n * sizeof(FILE) + n * sizeof(__sfileext)];
if (data == nullptr) return nullptr;
char* data = new char[sizeof(glue) + ALIGNBYTES + n * sizeof(FILE) + n * sizeof(__sfileext)];
if (data == nullptr) return nullptr;
glue* g = reinterpret_cast<glue*>(data);
FILE* p = reinterpret_cast<FILE*>(ALIGN(data + sizeof(*g)));
__sfileext* pext = reinterpret_cast<__sfileext*>(ALIGN(data + sizeof(*g)) + n * sizeof(FILE));
g->next = NULL;
g->niobs = n;
g->iobs = p;
while (--n >= 0) {
*p = empty;
_FILEEXT_SETUP(p, pext);
p++;
pext++;
}
return g;
glue* g = reinterpret_cast<glue*>(data);
FILE* p = reinterpret_cast<FILE*>(ALIGN(data + sizeof(*g)));
__sfileext* pext = reinterpret_cast<__sfileext*>(ALIGN(data + sizeof(*g)) + n * sizeof(FILE));
g->next = NULL;
g->niobs = n;
g->iobs = p;
while (--n >= 0) {
*p = empty;
_FILEEXT_SETUP(p, pext);
p++;
pext++;
}
return g;
}
/*
@ -147,81 +161,155 @@ found:
}
extern "C" __LIBC_HIDDEN__ void __libc_stdio_cleanup(void) {
/* (void) _fwalk(fclose); */
(void) _fwalk(__sflush); /* `cheating' */
// Equivalent to fflush(nullptr), but without all the locking since we're shutting down anyway.
_fwalk(__sflush);
}
int fclose(FILE* fp) {
if (fp->_flags == 0) {
// Already freed!
errno = EBADF;
return EOF;
}
if (fp->_flags == 0) {
// Already freed!
errno = EBADF;
return EOF;
}
FLOCKFILE(fp);
WCIO_FREE(fp);
int r = fp->_flags & __SWR ? __sflush(fp) : 0;
if (fp->_close != NULL && (*fp->_close)(fp->_cookie) < 0) {
r = EOF;
}
if (fp->_flags & __SMBF) free(fp->_bf._base);
if (HASUB(fp)) FREEUB(fp);
if (HASLB(fp)) FREELB(fp);
ScopedFileLock sfl(fp);
WCIO_FREE(fp);
int r = fp->_flags & __SWR ? __sflush(fp) : 0;
if (fp->_close != NULL && (*fp->_close)(fp->_cookie) < 0) {
r = EOF;
}
if (fp->_flags & __SMBF) free(fp->_bf._base);
if (HASUB(fp)) FREEUB(fp);
if (HASLB(fp)) FREELB(fp);
// Poison this FILE so accesses after fclose will be obvious.
fp->_file = -1;
fp->_r = fp->_w = 0;
// Poison this FILE so accesses after fclose will be obvious.
fp->_file = -1;
fp->_r = fp->_w = 0;
// Release this FILE for reuse.
fp->_flags = 0;
FUNLOCKFILE(fp);
return (r);
// Release this FILE for reuse.
fp->_flags = 0;
return r;
}
int fileno(FILE* fp) {
FLOCKFILE(fp);
int result = fileno_unlocked(fp);
FUNLOCKFILE(fp);
return result;
ScopedFileLock sfl(fp);
return fileno_unlocked(fp);
}
// Small standard I/O/seek/close functions.
// These maintain the `known seek offset' for seek optimisation.
int __sread(void* cookie, char* buf, int n) {
FILE* fp = reinterpret_cast<FILE*>(cookie);
int ret = TEMP_FAILURE_RETRY(read(fp->_file, buf, n));
// If the read succeeded, update the current offset.
if (ret >= 0) {
fp->_offset += ret;
} else {
fp->_flags &= ~__SOFF; // Paranoia.
}
return ret;
FILE* fp = reinterpret_cast<FILE*>(cookie);
return TEMP_FAILURE_RETRY(read(fp->_file, buf, n));
}
int __swrite(void* cookie, const char* buf, int n) {
FILE* fp = reinterpret_cast<FILE*>(cookie);
if (fp->_flags & __SAPP) {
(void) TEMP_FAILURE_RETRY(lseek(fp->_file, 0, SEEK_END));
}
fp->_flags &= ~__SOFF; // In case FAPPEND mode is set.
return TEMP_FAILURE_RETRY(write(fp->_file, buf, n));
FILE* fp = reinterpret_cast<FILE*>(cookie);
if (fp->_flags & __SAPP) {
// The FILE* is in append mode, but the underlying fd doesn't have O_APPEND set.
// We need to seek manually.
// TODO: can we use fcntl(2) to set O_APPEND in fdopen(3) instead?
TEMP_FAILURE_RETRY(lseek64(fp->_file, 0, SEEK_END));
}
return TEMP_FAILURE_RETRY(write(fp->_file, buf, n));
}
// TODO: _FILE_OFFSET_BITS=64.
fpos_t __sseek(void* cookie, fpos_t offset, int whence) {
FILE* fp = reinterpret_cast<FILE*>(cookie);
off_t ret = TEMP_FAILURE_RETRY(lseek(fp->_file, offset, whence));
if (ret == -1) {
fp->_flags &= ~__SOFF;
} else {
fp->_flags |= __SOFF;
fp->_offset = ret;
}
return ret;
FILE* fp = reinterpret_cast<FILE*>(cookie);
return TEMP_FAILURE_RETRY(lseek(fp->_file, offset, whence));
}
int __sclose(void* cookie) {
FILE* fp = reinterpret_cast<FILE*>(cookie);
return close(fp->_file);
FILE* fp = reinterpret_cast<FILE*>(cookie);
return close(fp->_file);
}
static bool __file_is_seekable(FILE* fp) {
if (fp->_seek == nullptr) {
errno = ESPIPE; // Historic practice.
return false;
}
return true;
}
// TODO: _FILE_OFFSET_BITS=64.
static off_t __ftello_unlocked(FILE* fp) {
if (!__file_is_seekable(fp)) return -1;
// Find offset of underlying I/O object, then
// adjust for buffered bytes.
__sflush(fp); // May adjust seek offset on append stream.
fpos_t result = (*fp->_seek)(fp->_cookie, 0, SEEK_CUR);
if (result == -1) {
return -1;
}
if (fp->_flags & __SRD) {
// Reading. Any unread characters (including
// those from ungetc) cause the position to be
// smaller than that in the underlying object.
result -= fp->_r;
if (HASUB(fp)) result -= fp->_ur;
} else if (fp->_flags & __SWR && fp->_p != NULL) {
// Writing. Any buffered characters cause the
// position to be greater than that in the
// underlying object.
result += fp->_p - fp->_bf._base;
}
return result;
}
int fseeko(FILE* fp, off_t offset, int whence) {
ScopedFileLock sfl(fp);
if (!__file_is_seekable(fp)) return -1;
// Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
// After this, whence is either SEEK_SET or SEEK_END.
if (whence == SEEK_CUR) {
fpos_t current_offset = __ftello_unlocked(fp);
if (current_offset == -1) {
return EOF;
}
offset += current_offset;
whence = SEEK_SET;
} else if (whence != SEEK_SET && whence != SEEK_END) {
errno = EINVAL;
return EOF;
}
if (fp->_bf._base == NULL) __smakebuf(fp);
// Flush unwritten data and attempt the seek.
if (__sflush(fp) || (*fp->_seek)(fp->_cookie, offset, whence) == -1) {
return EOF;
}
// Success: clear EOF indicator and discard ungetc() data.
if (HASUB(fp)) FREEUB(fp);
fp->_p = fp->_bf._base;
fp->_r = 0;
/* fp->_w = 0; */ /* unnecessary (I think...) */
fp->_flags &= ~__SEOF;
return 0;
}
// TODO: _FILE_OFFSET_BITS=64.
int fseek(FILE* fp, long offset, int whence) {
return fseeko(fp, offset, whence);
}
// TODO: _FILE_OFFSET_BITS=64.
off_t ftello(FILE* fp) {
ScopedFileLock sfl(fp);
return __ftello_unlocked(fp);
}
// TODO: _FILE_OFFSET_BITS=64
long ftell(FILE* fp) {
off_t offset = ftello(fp);
if (offset > LONG_MAX) {
errno = EOVERFLOW;
return -1;
}
return offset;
}

251
libc/upstream-openbsd/lib/libc/stdio/fseek.c
View File

@ -1,251 +0,0 @@
/* $OpenBSD: fseek.c,v 1.11 2012/05/21 22:24:19 matthew Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include "local.h"
#define POS_ERR (-(fpos_t)1)
/*
* Seek the given file to the given offset.
* `Whence' must be one of the three SEEK_* macros.
*/
int
fseeko(FILE *fp, off_t offset, int whence)
{
fpos_t (*seekfn)(void *, fpos_t, int);
fpos_t target, curoff;
size_t n;
struct stat st;
int havepos;
/* make sure stdio is set up */
if (!__sdidinit)
__sinit();
/*
* Have to be able to seek.
*/
if ((seekfn = fp->_seek) == NULL) {
errno = ESPIPE; /* historic practice */
return (EOF);
}
/*
* Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
* After this, whence is either SEEK_SET or SEEK_END.
*/
FLOCKFILE(fp);
switch (whence) {
case SEEK_CUR:
/*
* In order to seek relative to the current stream offset,
* we have to first find the current stream offset a la
* ftell (see ftell for details).
*/
__sflush(fp); /* may adjust seek offset on append stream */
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else {
curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
if (curoff == (fpos_t)-1) {
FUNLOCKFILE(fp);
return (EOF);
}
}
if (fp->_flags & __SRD) {
curoff -= fp->_r;
if (HASUB(fp))
curoff -= fp->_ur;
} else if (fp->_flags & __SWR && fp->_p != NULL)
curoff += fp->_p - fp->_bf._base;
offset += curoff;
whence = SEEK_SET;
havepos = 1;
break;
case SEEK_SET:
case SEEK_END:
curoff = 0; /* XXX just to keep gcc quiet */
havepos = 0;
break;
default:
FUNLOCKFILE(fp);
errno = EINVAL;
return (EOF);
}
/*
* Can only optimise if:
* reading (and not reading-and-writing);
* not unbuffered; and
* this is a `regular' Unix file (and hence seekfn==__sseek).
* We must check __NBF first, because it is possible to have __NBF
* and __SOPT both set.
*/
if (fp->_bf._base == NULL)
__smakebuf(fp);
if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
goto dumb;
if ((fp->_flags & __SOPT) == 0) {
if (seekfn != __sseek ||
fp->_file < 0 || fstat(fp->_file, &st) ||
(st.st_mode & S_IFMT) != S_IFREG) {
fp->_flags |= __SNPT;
goto dumb;
}
fp->_blksize = st.st_blksize;
fp->_flags |= __SOPT;
}
/*
* We are reading; we can try to optimise.
* Figure out where we are going and where we are now.
*/
if (whence == SEEK_SET)
target = offset;
else {
if (fstat(fp->_file, &st))
goto dumb;
target = st.st_size + offset;
}
if (!havepos) {
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else {
curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
if (curoff == POS_ERR)
goto dumb;
}
curoff -= fp->_r;
if (HASUB(fp))
curoff -= fp->_ur;
}
/*
* Compute the number of bytes in the input buffer (pretending
* that any ungetc() input has been discarded). Adjust current
* offset backwards by this count so that it represents the
* file offset for the first byte in the current input buffer.
*/
if (HASUB(fp)) {
curoff += fp->_r; /* kill off ungetc */
n = fp->_up - fp->_bf._base;
curoff -= n;
n += fp->_ur;
} else {
n = fp->_p - fp->_bf._base;
curoff -= n;
n += fp->_r;
}
/*
* If the target offset is within the current buffer,
* simply adjust the pointers, clear EOF, undo ungetc(),
* and return. (If the buffer was modified, we have to
* skip this; see fgetln.c.)
*/
if ((fp->_flags & __SMOD) == 0 &&
target >= curoff && target < curoff + n) {
int o = target - curoff;
fp->_p = fp->_bf._base + o;
fp->_r = n - o;
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~__SEOF;
FUNLOCKFILE(fp);
return (0);
}
/*
* The place we want to get to is not within the current buffer,
* but we can still be kind to the kernel copyout mechanism.
* By aligning the file offset to a block boundary, we can let
* the kernel use the VM hardware to map pages instead of
* copying bytes laboriously. Using a block boundary also
* ensures that we only read one block, rather than two.
*/
curoff = target & ~(fp->_blksize - 1);
if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
goto dumb;
fp->_r = 0;
fp->_p = fp->_bf._base;
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~__SEOF;
n = target - curoff;
if (n) {
if (__srefill(fp) || fp->_r < n)
goto dumb;
fp->_p += n;
fp->_r -= n;
}
FUNLOCKFILE(fp);
return (0);
/*
* We get here if we cannot optimise the seek ... just
* do it. Allow the seek function to change fp->_bf._base.
*/
dumb:
if (__sflush(fp) ||
(*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR) {
FUNLOCKFILE(fp);
return (EOF);
}
/* success: clear EOF indicator and discard ungetc() data */
if (HASUB(fp))
FREEUB(fp);
fp->_p = fp->_bf._base;
fp->_r = 0;
/* fp->_w = 0; */ /* unnecessary (I think...) */
fp->_flags &= ~__SEOF;
FUNLOCKFILE(fp);
return (0);
}
int
fseek(FILE *fp, long offset, int whence)
{
return (fseeko(fp, offset, whence));
}

96
libc/upstream-openbsd/lib/libc/stdio/ftell.c
View File

@ -1,96 +0,0 @@
/* $OpenBSD: ftell.c,v 1.10 2012/05/21 22:24:19 matthew Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include "local.h"
/*
* ftello: return current offset.
*/
off_t
ftello(FILE *fp)
{
fpos_t pos;
if (fp->_seek == NULL) {
errno = ESPIPE; /* historic practice */
pos = -1;
goto out;
}
/*
* Find offset of underlying I/O object, then
* adjust for buffered bytes.
*/
FLOCKFILE(fp);
__sflush(fp); /* may adjust seek offset on append stream */
if (fp->_flags & __SOFF)
pos = fp->_offset;
else {
pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR);
if (pos == -1)
goto out;
}
if (fp->_flags & __SRD) {
/*
* Reading. Any unread characters (including
* those from ungetc) cause the position to be
* smaller than that in the underlying object.
*/
pos -= fp->_r;
if (HASUB(fp))
pos -= fp->_ur;
} else if (fp->_flags & __SWR && fp->_p != NULL) {
/*
* Writing. Any buffered characters cause the
* position to be greater than that in the
* underlying object.
*/
pos += fp->_p - fp->_bf._base;
}
out: FUNLOCKFILE(fp);
return (pos);
}
long
ftell(FILE *fp)
{
off_t offset = ftello(fp);
if (offset > LONG_MAX) {
errno = EOVERFLOW;
return (-1);
}
return ((long)offset);
}

25
tests/stdio_test.cpp
View File

@ -1068,3 +1068,28 @@ TEST(STDIO_TEST, fclose_invalidates_fd) {
ASSERT_EQ(-1, fileno(stdin));
ASSERT_EQ(EBADF, errno);
}
TEST(STDIO_TEST, fseek_ftell_unseekable) {
#if defined(__BIONIC__) // glibc has fopencookie instead.
auto read_fn = [](void*, char*, int) { return -1; };
FILE* fp = funopen(nullptr, read_fn, nullptr, nullptr, nullptr);
ASSERT_TRUE(fp != nullptr);
// Check that ftell balks on an unseekable FILE*.
errno = 0;
ASSERT_EQ(-1, ftell(fp));
ASSERT_EQ(ESPIPE, errno);
// SEEK_CUR is rewritten as SEEK_SET internally...
errno = 0;
ASSERT_EQ(-1, fseek(fp, 0, SEEK_CUR));
ASSERT_EQ(ESPIPE, errno);
// ...so it's worth testing the direct seek path too.
errno = 0;
ASSERT_EQ(-1, fseek(fp, 0, SEEK_SET));
ASSERT_EQ(ESPIPE, errno);
fclose(fp);
#endif
}