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Move our p{read,write}v replacements into their own files.

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macOS's ranlib issued a warning about an empty pread.o file with the
previous arrangement, on systems new enough to require no replacement
functions.  Let's go back to using configure's AC_REPLACE_FUNCS system
to build and include each .o in the library only if it's needed, which
requires moving the *v() functions to their own files.

Also move the _with_retry() wrapper to a more permanent home.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1283127.1610554395%40sss.pgh.pa.us
This commit is contained in:
Thomas Munro 2021-01-14 11:10:24 +13:00
parent 5a6f9bce8d
commit 0d56acfbaa
10 changed files with 248 additions and 154 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
configure vendored
View File

@ -15155,7 +15155,7 @@ fi
LIBS_including_readline="$LIBS"
LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pread preadv pstat pthread_is_threaded_np pwrite pwritev readlink readv setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range uselocale wcstombs_l writev
for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink readv setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range uselocale wcstombs_l writev
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
@ -15832,6 +15832,58 @@ esac
fi
ac_fn_c_check_func "$LINENO" "pread" "ac_cv_func_pread"
if test "x$ac_cv_func_pread" = xyes; then :
$as_echo "#define HAVE_PREAD 1" >>confdefs.h
else
case " $LIBOBJS " in
*" pread.$ac_objext "* ) ;;
*) LIBOBJS="$LIBOBJS pread.$ac_objext"
;;
esac
fi
ac_fn_c_check_func "$LINENO" "preadv" "ac_cv_func_preadv"
if test "x$ac_cv_func_preadv" = xyes; then :
$as_echo "#define HAVE_PREADV 1" >>confdefs.h
else
case " $LIBOBJS " in
*" preadv.$ac_objext "* ) ;;
*) LIBOBJS="$LIBOBJS preadv.$ac_objext"
;;
esac
fi
ac_fn_c_check_func "$LINENO" "pwrite" "ac_cv_func_pwrite"
if test "x$ac_cv_func_pwrite" = xyes; then :
$as_echo "#define HAVE_PWRITE 1" >>confdefs.h
else
case " $LIBOBJS " in
*" pwrite.$ac_objext "* ) ;;
*) LIBOBJS="$LIBOBJS pwrite.$ac_objext"
;;
esac
fi
ac_fn_c_check_func "$LINENO" "pwritev" "ac_cv_func_pwritev"
if test "x$ac_cv_func_pwritev" = xyes; then :
$as_echo "#define HAVE_PWRITEV 1" >>confdefs.h
else
case " $LIBOBJS " in
*" pwritev.$ac_objext "* ) ;;
*) LIBOBJS="$LIBOBJS pwritev.$ac_objext"
;;
esac
fi
ac_fn_c_check_func "$LINENO" "random" "ac_cv_func_random"
if test "x$ac_cv_func_random" = xyes; then :
$as_echo "#define HAVE_RANDOM 1" >>confdefs.h

8
configure.ac
View File

@ -1661,12 +1661,8 @@ AC_CHECK_FUNCS(m4_normalize([
poll
posix_fallocate
ppoll
pread
preadv
pstat
pthread_is_threaded_np
pwrite
pwritev
readlink
readv
setproctitle
@ -1740,6 +1736,10 @@ AC_REPLACE_FUNCS(m4_normalize([
inet_aton
link
mkdtemp
pread
preadv
pwrite
pwritev
random
srandom
strlcat

65
src/backend/storage/file/fd.c
View File

@ -92,6 +92,7 @@
#include "common/file_utils.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/pg_iovec.h"
#include "portability/mem.h"
#include "storage/fd.h"
#include "storage/ipc.h"
@ -3635,3 +3636,67 @@ data_sync_elevel(int elevel)
{
return data_sync_retry ? elevel : PANIC;
}
/*
* A convenience wrapper for pg_pwritev() that retries on partial write. If an
* error is returned, it is unspecified how much has been written.
*/
ssize_t
pg_pwritev_with_retry(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
struct iovec iov_copy[PG_IOV_MAX];
ssize_t sum = 0;
ssize_t part;
/* We'd better have space to make a copy, in case we need to retry. */
if (iovcnt > PG_IOV_MAX)
{
errno = EINVAL;
return -1;
}
for (;;)
{
/* Write as much as we can. */
part = pg_pwritev(fd, iov, iovcnt, offset);
if (part < 0)
return -1;
#ifdef SIMULATE_SHORT_WRITE
part = Min(part, 4096);
#endif
/* Count our progress. */
sum += part;
offset += part;
/* Step over iovecs that are done. */
while (iovcnt > 0 && iov->iov_len <= part)
{
part -= iov->iov_len;
++iov;
--iovcnt;
}
/* Are they all done? */
if (iovcnt == 0)
{
/* We don't expect the kernel to write more than requested. */
Assert(part == 0);
break;
}
/*
* Move whatever's left to the front of our mutable copy and adjust
* the leading iovec.
*/
Assert(iovcnt > 0);
memmove(iov_copy, iov, sizeof(*iov) * iovcnt);
Assert(iov->iov_len > part);
iov_copy[0].iov_base = (char *) iov_copy[0].iov_base + part;
iov_copy[0].iov_len -= part;
iov = iov_copy;
}
return sum;
}

5
src/include/storage/fd.h
View File

@ -45,6 +45,7 @@
#include <dirent.h>
struct iovec; /* avoid including port/pg_iovec.h here */
typedef int File;
@ -161,6 +162,10 @@ extern int durable_unlink(const char *fname, int loglevel);
extern int durable_rename_excl(const char *oldfile, const char *newfile, int loglevel);
extern void SyncDataDirectory(void);
extern int data_sync_elevel(int elevel);
extern ssize_t pg_pwritev_with_retry(int fd,
const struct iovec *iov,
int iovcnt,
off_t offset);
/* Filename components */
#define PG_TEMP_FILES_DIR "pgsql_tmp"

2
src/port/Makefile
View File

@ -53,8 +53,6 @@ OBJS = \
pgstrcasecmp.o \
pgstrsignal.o \
pqsignal.o \
pread.o \
pwrite.o \
qsort.o \
qsort_arg.o \
quotes.o \

43
src/port/pread.c
View File

@ -1,7 +1,7 @@
/*-------------------------------------------------------------------------
*
* pread.c
* Implementation of pread[v](2) for platforms that lack one.
* Implementation of pread(2) for platforms that lack one.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
*
@ -9,8 +9,7 @@
* src/port/pread.c
*
* Note that this implementation changes the current file position, unlike
* the POSIX function, so we use the name pg_pread(). Likewise for the
* iovec version.
* the POSIX function, so we use the name pg_pread().
*
*-------------------------------------------------------------------------
*/
@ -24,9 +23,6 @@
#include <unistd.h>
#endif
#include "port/pg_iovec.h"
#ifndef HAVE_PREAD
ssize_t
pg_pread(int fd, void *buf, size_t size, off_t offset)
{
@ -60,38 +56,3 @@ pg_pread(int fd, void *buf, size_t size, off_t offset)
return read(fd, buf, size);
#endif
}
#endif
#ifndef HAVE_PREADV
ssize_t
pg_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
#ifdef HAVE_READV
if (iovcnt == 1)
return pg_pread(fd, iov[0].iov_base, iov[0].iov_len, offset);
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;
return readv(fd, iov, iovcnt);
#else
ssize_t sum = 0;
ssize_t part;
for (int i = 0; i < iovcnt; ++i)
{
part = pg_pread(fd, iov[i].iov_base, iov[i].iov_len, offset);
if (part < 0)
{
if (i == 0)
return -1;
else
return sum;
}
sum += part;
offset += part;
if (part < iov[i].iov_len)
return sum;
}
return sum;
#endif
}
#endif

58
src/port/preadv.c Normal file
View File

@ -0,0 +1,58 @@
/*-------------------------------------------------------------------------
*
* preadv.c
* Implementation of preadv(2) for platforms that lack one.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/port/preadv.c
*
* Note that this implementation changes the current file position, unlike
* the POSIX-like function, so we use the name pg_preadv().
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#ifdef WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif
#include "port/pg_iovec.h"
ssize_t
pg_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
#ifdef HAVE_READV
if (iovcnt == 1)
return pg_pread(fd, iov[0].iov_base, iov[0].iov_len, offset);
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;
return readv(fd, iov, iovcnt);
#else
ssize_t sum = 0;
ssize_t part;
for (int i = 0; i < iovcnt; ++i)
{
part = pg_pread(fd, iov[i].iov_base, iov[i].iov_len, offset);
if (part < 0)
{
if (i == 0)
return -1;
else
return sum;
}
sum += part;
offset += part;
if (part < iov[i].iov_len)
return sum;
}
return sum;
#endif
}

107
src/port/pwrite.c
View File

@ -1,7 +1,7 @@
/*-------------------------------------------------------------------------
*
* pwrite.c
* Implementation of pwrite[v](2) for platforms that lack one.
* Implementation of pwrite(2) for platforms that lack one.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
*
@ -9,8 +9,7 @@
* src/port/pwrite.c
*
* Note that this implementation changes the current file position, unlike
* the POSIX function, so we use the name pg_pwrite(). Likewise for the
* iovec version.
* the POSIX function, so we use the name pg_pwrite().
*
*-------------------------------------------------------------------------
*/
@ -24,9 +23,6 @@
#include <unistd.h>
#endif
#include "port/pg_iovec.h"
#ifndef HAVE_PWRITE
ssize_t
pg_pwrite(int fd, const void *buf, size_t size, off_t offset)
{
@ -57,102 +53,3 @@ pg_pwrite(int fd, const void *buf, size_t size, off_t offset)
return write(fd, buf, size);
#endif
}
#endif
#ifndef HAVE_PWRITEV
ssize_t
pg_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
#ifdef HAVE_WRITEV
if (iovcnt == 1)
return pg_pwrite(fd, iov[0].iov_base, iov[0].iov_len, offset);
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;
return writev(fd, iov, iovcnt);
#else
ssize_t sum = 0;
ssize_t part;
for (int i = 0; i < iovcnt; ++i)
{
part = pg_pwrite(fd, iov[i].iov_base, iov[i].iov_len, offset);
if (part < 0)
{
if (i == 0)
return -1;
else
return sum;
}
sum += part;
offset += part;
if (part < iov[i].iov_len)
return sum;
}
return sum;
#endif
}
#endif
/*
* A convenience wrapper for pg_pwritev() that retries on partial write. If an
* error is returned, it is unspecified how much has been written.
*/
ssize_t
pg_pwritev_with_retry(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
struct iovec iov_copy[PG_IOV_MAX];
ssize_t sum = 0;
ssize_t part;
/* We'd better have space to make a copy, in case we need to retry. */
if (iovcnt > PG_IOV_MAX)
{
errno = EINVAL;
return -1;
}
for (;;)
{
/* Write as much as we can. */
part = pg_pwritev(fd, iov, iovcnt, offset);
if (part < 0)
return -1;
#ifdef SIMULATE_SHORT_WRITE
part = Min(part, 4096);
#endif
/* Count our progress. */
sum += part;
offset += part;
/* Step over iovecs that are done. */
while (iovcnt > 0 && iov->iov_len <= part)
{
part -= iov->iov_len;
++iov;
--iovcnt;
}
/* Are they all done? */
if (iovcnt == 0)
{
/* We don't expect the kernel to write more than requested. */
Assert(part == 0);
break;
}
/*
* Move whatever's left to the front of our mutable copy and adjust
* the leading iovec.
*/
Assert(iovcnt > 0);
memmove(iov_copy, iov, sizeof(*iov) * iovcnt);
Assert(iov->iov_len > part);
iov_copy[0].iov_base = (char *) iov_copy[0].iov_base + part;
iov_copy[0].iov_len -= part;
iov = iov_copy;
}
return sum;
}

58
src/port/pwritev.c Normal file
View File

@ -0,0 +1,58 @@
/*-------------------------------------------------------------------------
*
* pwritev.c
* Implementation of pwritev(2) for platforms that lack one.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/port/pwritev.c
*
* Note that this implementation changes the current file position, unlike
* the POSIX-like function, so we use the name pg_pwritev().
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#ifdef WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif
#include "port/pg_iovec.h"
ssize_t
pg_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
#ifdef HAVE_WRITEV
if (iovcnt == 1)
return pg_pwrite(fd, iov[0].iov_base, iov[0].iov_len, offset);
if (lseek(fd, offset, SEEK_SET) < 0)
return -1;
return writev(fd, iov, iovcnt);
#else
ssize_t sum = 0;
ssize_t part;
for (int i = 0; i < iovcnt; ++i)
{
part = pg_pwrite(fd, iov[i].iov_base, iov[i].iov_len, offset);
if (part < 0)
{
if (i == 0)
return -1;
else
return sum;
}
sum += part;
offset += part;
if (part < iov[i].iov_len)
return sum;
}
return sum;
#endif
}

2
src/tools/msvc/Mkvcbuild.pm
View File

@ -99,7 +99,7 @@ sub mkvcbuild
srandom.c getaddrinfo.c gettimeofday.c inet_net_ntop.c kill.c open.c
erand48.c snprintf.c strlcat.c strlcpy.c dirmod.c noblock.c path.c
dirent.c dlopen.c getopt.c getopt_long.c link.c
pread.c pwrite.c pg_bitutils.c
pread.c preadv.c pwrite.c pwritev.c pg_bitutils.c
pg_strong_random.c pgcheckdir.c pgmkdirp.c pgsleep.c pgstrcasecmp.c
pqsignal.c mkdtemp.c qsort.c qsort_arg.c quotes.c system.c
strerror.c tar.c thread.c