From b041d3e3a17331f9fc76509a577c6ed63067aded Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sat, 13 Sep 2003 14:49:51 +0000
Subject: [PATCH] Attempt threading in this order:
* use non-*_r function names if they are all thread-safe
* (NEED_REENTRANT_FUNCS=no)
* use *_r functions if they exist (configure test)
* do our own locking and copying of non-threadsafe functions
New to this patch is the last option.
---
configure.in | 11 +--
src/include/port.h | 10 +--
src/port/thread.c | 173 +++++++++++++++++++++++++++++++++++++-----
src/template/bsdi | 2 +-
src/template/freebsd | 4 +-
src/template/linux | 2 +-
src/template/netbsd | 2 +-
src/template/osf | 2 +-
src/template/solaris | 5 ++
src/template/unixware | 2 +-
10 files changed, 176 insertions(+), 37 deletions(-)
diff --git a/configure.in b/configure.in
index 62c14eeb286..9ca208f5f3f 100644
--- a/configure.in
+++ b/configure.in
@@ -1,5 +1,5 @@
dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.287 2003/09/12 16:10:26 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.288 2003/09/13 14:49:51 momjian Exp $
dnl
dnl Developers, please strive to achieve this order:
dnl
@@ -1031,17 +1031,12 @@ AC_SUBST(THREAD_LIBS)
# One trick here is that if we don't call AC_CHECK_FUNCS, the
# functions are marked "not found", which is perfect.
#
-if test "$enable_thread_safety" = yes -a "$NEED_REENTRANT_FUNC_NAMES" = yes ; then
+if test "$enable_thread_safety" = yes -a "$NEED_REENTRANT_FUNCS" = yes ; then
_CFLAGS="$CFLAGS"
_LIBS="$LIBS"
CFLAGS="$CFLAGS $THREAD_CFLAGS"
LIBS="$LIBS $THREAD_LIBS"
-AC_CHECK_FUNC(strerror_r,
- [], [AC_MSG_ERROR([strerror_r not found, required on this platform for --enable-thread-safety])])
-AC_CHECK_FUNC(getpwuid_r,
- [], [AC_MSG_ERROR([getpwuid_r not found, required on this platform for --enable-thread-safety])])
-AC_CHECK_FUNC(gethostbyname_r,
- [], [AC_MSG_ERROR([gethostbyname_r not found, required on this platform for --enable-thread-safety])])
+AC_CHECK_FUNCS([strerror_r getpwuid_r gethostbyname_r])
CFLAGS="$_CFLAGS"
LIBS="$_LIBS"
fi
diff --git a/src/include/port.h b/src/include/port.h
index 6b801ba424a..d77dd652f15 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: port.h,v 1.13 2003/09/05 17:43:39 momjian Exp $
+ * $Id: port.h,v 1.14 2003/09/13 14:49:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -114,11 +114,11 @@ extern char *pqStrerror(int errnum, char *strerrbuf, size_t buflen);
#ifndef WIN32
extern int pqGetpwuid(uid_t uid, struct passwd * resultbuf, char *buffer,
- size_t buflen, struct passwd ** result);
+ size_t buflen, struct passwd **result);
#endif
extern int pqGethostbyname(const char *name,
- struct hostent * resbuf,
- char *buf, size_t buflen,
- struct hostent ** result,
+ struct hostent *resultbuf,
+ char *buffer, size_t buflen,
+ struct hostent **result,
int *herrno);
diff --git a/src/port/thread.c b/src/port/thread.c
index c00202a0631..193b2e0808b 100644
--- a/src/port/thread.c
+++ b/src/port/thread.c
@@ -7,19 +7,24 @@
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
*
- * $Id: thread.c,v 1.6 2003/09/05 17:43:40 momjian Exp $
+ * $Id: thread.c,v 1.7 2003/09/13 14:49:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+#include <pthread.h>
+#include <sys/types.h>
+#include <pwd.h>
+
/*
* Threading sometimes requires specially-named versions of functions
* that return data in static buffers, like strerror_r() instead of
* strerror(). Other operating systems use pthread_setspecific()
* and pthread_getspecific() internally to allow standard library
- * functions to return static data to threaded applications.
+ * functions to return static data to threaded applications. And some
+ * operating systems have neither, meaning we have to do our own locking.
*
* Additional confusion exists because many operating systems that
* use pthread_setspecific/pthread_getspecific() also have *_r versions
@@ -36,11 +41,15 @@
* doesn't have strerror_r(), so we can't fall back to only using *_r
* functions for threaded programs.
*
- * The current setup is to assume either all standard functions are
- * thread-safe (NEED_REENTRANT_FUNC_NAMES=no), or the operating system
- * requires reentrant function names (NEED_REENTRANT_FUNC_NAMES=yes).
+ * The current setup is to try threading in this order:
+ *
+ * use non-*_r function names if they are all thread-safe
+ * (NEED_REENTRANT_FUNCS=no)
+ * use *_r functions if they exist (configure test)
+ * do our own locking and copying of non-threadsafe functions
+ *
* Compile and run src/tools/test_thread_funcs.c to see if your operating
- * system requires reentrant function names.
+ * system has thread-safe non-*_r functions.
*/
@@ -51,14 +60,27 @@
char *
pqStrerror(int errnum, char *strerrbuf, size_t buflen)
{
-#if defined(USE_THREADS) && defined(NEED_REENTRANT_FUNC_NAMES)
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_STRERROR_R)
/* reentrant strerror_r is available */
/* some early standards had strerror_r returning char * */
strerror_r(errnum, strerrbuf, buflen);
- return (strerrbuf);
+ return strerrbuf;
+
#else
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_STRERROR_R)
+ static pthread_mutex_t strerror_lock = PTHREAD_MUTEX_INITIALIZER;
+ pthread_mutex_lock(&strerror_lock);
+#endif
+
/* no strerror_r() available, just use strerror */
- return strerror(errnum);
+ StrNCpy(strerrbuf, strerror(errnum), buflen);
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_STRERROR_R)
+ pthread_mutex_unlock(&strerror_lock);
+#endif
+
+ return strerrbuf;
#endif
}
@@ -71,7 +93,7 @@ int
pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result)
{
-#if defined(USE_THREADS) && defined(NEED_REENTRANT_FUNC_NAMES)
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_GETPWUID_R)
/*
* Early POSIX draft of getpwuid_r() returns 'struct passwd *'.
* getpwuid_r(uid, resultbuf, buffer, buflen)
@@ -79,9 +101,52 @@ pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
*/
/* POSIX version */
getpwuid_r(uid, resultbuf, buffer, buflen, result);
+
#else
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETPWUID_R)
+ static pthread_mutex_t getpwuid_lock = PTHREAD_MUTEX_INITIALIZER;
+ pthread_mutex_lock(&getpwuid_lock);
+#endif
+
/* no getpwuid_r() available, just use getpwuid() */
*result = getpwuid(uid);
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETPWUID_R)
+
+ /* Use 'buffer' memory for storage of strings used by struct passwd */
+ if (*result &&
+ strlen((*result)->pw_name) + 1 +
+ strlen((*result)->pw_passwd) + 1 +
+ strlen((*result)->pw_gecos) + 1 +
+ /* skip class if it exists */
+ strlen((*result)->pw_dir) + 1 +
+ strlen((*result)->pw_shell) + 1 <= buflen)
+ {
+ memcpy(resultbuf, *result, sizeof(struct passwd));
+ strcpy(buffer, (*result)->pw_name);
+ resultbuf->pw_name = buffer;
+ buffer += strlen(resultbuf->pw_name) + 1;
+ strcpy(buffer, (*result)->pw_passwd);
+ resultbuf->pw_passwd = buffer;
+ buffer += strlen(resultbuf->pw_passwd) + 1;
+ strcpy(buffer, (*result)->pw_gecos);
+ resultbuf->pw_gecos = buffer;
+ buffer += strlen(resultbuf->pw_gecos) + 1;
+ strcpy(buffer, (*result)->pw_dir);
+ resultbuf->pw_dir = buffer;
+ buffer += strlen(resultbuf->pw_dir) + 1;
+ strcpy(buffer, (*result)->pw_shell);
+ resultbuf->pw_shell = buffer;
+ buffer += strlen(resultbuf->pw_shell) + 1;
+
+ *result = resultbuf;
+ }
+ else
+ *result = NULL;
+
+ pthread_mutex_unlock(&getpwuid_lock);
+#endif
#endif
return (*result == NULL) ? -1 : 0;
}
@@ -93,27 +158,101 @@ pqGetpwuid(uid_t uid, struct passwd *resultbuf, char *buffer,
*/
int
pqGethostbyname(const char *name,
- struct hostent *resbuf,
- char *buf, size_t buflen,
+ struct hostent *resultbuf,
+ char *buffer, size_t buflen,
struct hostent **result,
int *herrno)
{
-#if defined(USE_THREADS) && defined(NEED_REENTRANT_FUNC_NAMES)
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && defined(HAVE_GETHOSTBYNAME_R)
/*
* broken (well early POSIX draft) gethostbyname_r() which returns
* 'struct hostent *'
*/
- *result = gethostbyname_r(name, resbuf, buf, buflen, herrno);
+ *result = gethostbyname_r(name, resbuf, buffer, buflen, herrno);
return (*result == NULL) ? -1 : 0;
+
#else
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R)
+ static pthread_mutex_t gethostbyname_lock = PTHREAD_MUTEX_INITIALIZER;
+ pthread_mutex_lock(&gethostbyname_lock);
+#endif
+
/* no gethostbyname_r(), just use gethostbyname() */
*result = gethostbyname(name);
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R)
+
+ /*
+ * Use 'buffer' memory for storage of structures used by struct hostent.
+ * The layout is:
+ *
+ * addr pointers
+ * alias pointers
+ * addr structures
+ * alias structures
+ * name
+ */
+ if (*result)
+ {
+ int i, pointers = 2 /* for nulls */, len = 0;
+ char **pbuffer;
+
+ for (i = 0; (*result)->h_addr_list[i]; i++, pointers++)
+ len += (*result)->h_length;
+ for (i = 0; (*result)->h_aliases[i]; i++, pointers++)
+ len += (*result)->h_length;
+
+ if (MAXALIGN(len) + pointers * sizeof(char *) + strlen((*result)->h_name) + 1 <= buflen)
+ {
+ memcpy(resultbuf, *result, sizeof(struct hostent));
+
+ pbuffer = (char **)buffer;
+ resultbuf->h_addr_list = pbuffer;
+ buffer += pointers * sizeof(char *);
+
+ for (i = 0; (*result)->h_addr_list[i]; i++, pbuffer++)
+ {
+ memcpy(buffer, (*result)->h_addr_list[i], (*result)->h_length);
+ resultbuf->h_addr_list[i] = buffer;
+ buffer += (*result)->h_length;
+ }
+ resultbuf->h_addr_list[i] = NULL;
+ pbuffer++;
+
+ resultbuf->h_aliases = pbuffer;
+
+ for (i = 0; (*result)->h_aliases[i]; i++, pbuffer++)
+ {
+ memcpy(buffer, (*result)->h_aliases[i], (*result)->h_length);
+ resultbuf->h_aliases[i] = buffer;
+ buffer += (*result)->h_length;
+ }
+ resultbuf->h_aliases[i] = NULL;
+ pbuffer++;
+
+ /* Place at end for cleaner alignment */
+ strcpy(buffer, (*result)->h_name);
+ resultbuf->h_name = buffer;
+ buffer += strlen(resultbuf->h_name) + 1;
+
+ *result = resultbuf;
+ }
+ else
+ *result = NULL;
+ }
+#endif
+
+ if (*result != NULL)
+ *herrno = h_errno;
+
+#if defined(FRONTEND) && defined(USE_THREADS) && defined(NEED_REENTRANT_FUNCS) && !defined(HAVE_GETHOSTBYNAME_R)
+ pthread_mutex_unlock(&gethostbyname_lock);
+#endif
+
if (*result != NULL)
return 0;
else
- {
- *herrno = h_errno;
return -1;
- }
#endif
}
diff --git a/src/template/bsdi b/src/template/bsdi
index ba2d27247e4..d6b16a2417d 100644
--- a/src/template/bsdi
+++ b/src/template/bsdi
@@ -11,4 +11,4 @@ case $host_os in
esac
SUPPORTS_THREADS=yes
-NEED_REENTRANT_FUNC_NAMES=no # verified 4.3 2003-09-03
+NEED_REENTRANT_FUNCS=no # verified 4.3 2003-09-03
diff --git a/src/template/freebsd b/src/template/freebsd
index 9e5cc6d0128..71e50140660 100644
--- a/src/template/freebsd
+++ b/src/template/freebsd
@@ -4,8 +4,8 @@ case $host_cpu in
alpha*) CFLAGS="$CFLAGS -O" ;;
esac
-SUPPORTS_THREADS=no # 4.8, 5.1 2003-09-12
-NEED_REENTRANT_FUNC_NAMES=no
+SUPPORTS_THREADS=yes
+NEED_REENTRANT_FUNCS=yes # 4.8, 5.1 2003-09-12
case $host_os in
freebsd2*|freebsd3*|freebsd4*)
diff --git a/src/template/linux b/src/template/linux
index db13803710e..0aab11631f5 100644
--- a/src/template/linux
+++ b/src/template/linux
@@ -1,7 +1,7 @@
CFLAGS=-O2
SUPPORTS_THREADS=yes
-NEED_REENTRANT_FUNC_NAMES=yes # verified glibc 2.1 2003-09-03
+NEED_REENTRANT_FUNCS=yes # verified glibc 2.1 2003-09-03
THREAD_CFLAGS="-D_REENTRANT -D_THREAD_SAFE -D_POSIX_PTHREAD_SEMANTICS"
THREAD_LIBS="-lpthread"
diff --git a/src/template/netbsd b/src/template/netbsd
index 9a3869dfe77..72e1d624c4a 100644
--- a/src/template/netbsd
+++ b/src/template/netbsd
@@ -1,4 +1,4 @@
CFLAGS='-O2 -pipe'
SUPPORTS_THREADS=yes
-NEED_REENTRANT_FUNC_NAMES=no
+NEED_REENTRANT_FUNCS=no
diff --git a/src/template/osf b/src/template/osf
index a930bf4e08e..7305395a0b2 100644
--- a/src/template/osf
+++ b/src/template/osf
@@ -6,5 +6,5 @@ else
fi
SUPPORTS_THREADS=yes
-NEED_REENTRANT_FUNC_NAMES=no
+NEED_REENTRANT_FUNCS=no # 4.0 2003-09-13
THREAD_CFLAGS="-pthread"
diff --git a/src/template/solaris b/src/template/solaris
index 33d40cfb87c..d839f935ccb 100644
--- a/src/template/solaris
+++ b/src/template/solaris
@@ -4,3 +4,8 @@ else
CC="$CC -Xa" # relaxed ISO C mode
CFLAGS=-v # -v is like gcc -Wall
fi
+
+SUPPORTS_THREADS=yes
+NEED_REENTRANT_FUNCS=yes # 5.6 2003-09-13
+THREAD_CFLAGS="-pthread"
+
diff --git a/src/template/unixware b/src/template/unixware
index 9cfde833c92..21d4314d87d 100644
--- a/src/template/unixware
+++ b/src/template/unixware
@@ -10,5 +10,5 @@ else
fi
SUPPORTS_THREADS=yes
-NEED_REENTRANT_FUNC_NAMES=no # verified 7.1.3 2003-09-03
+NEED_REENTRANT_FUNCS=no # verified 7.1.3 2003-09-03
THREAD_CFLAGS="$THREAD_CFLAGS -D_REENTRANT"
--
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