Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Yes, that is the logic in my patch, except that I don't check errno, I
> > just call sigpending().
>
> No, that's wrong: if there is a pending SIGPIPE that belongs to the
> outer app, you'd clear it.
True, but I documented that in the patch.
> > There are a few writes and it seemed impossible
> > to check them all.
>
> Hmm? There is only one place this needs to be done, namely
> pqsecure_write.
Look also in fe-print.c. Looks like a lot of popen writes in there.
I can do it but it will be harder.
> BTW, have you posted the patch yet or are you still working on it?
> The mail server seems a bit flaky today ...
OK, patch attached. I already sent it but who knows what happened to
it.
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
Index: configure
===================================================================
RCS file: /cvsroot/pgsql/configure,v
retrieving revision 1.409
diff -c -c -r1.409 configure
*** configure 30 Nov 2004 06:13:03 -0000 1.409
--- configure 1 Dec 2004 22:53:58 -0000
***************
*** 17431,17436 ****
--- 17431,17448 ----
fi
HAVE_POSIX_SIGNALS=$pgac_cv_func_posix_signals
+ if test "$pgac_cv_func_posix_signals" != yes -a "$enable_thread_safety" = yes; then
+ { { echo "$as_me:$LINENO: error:
+ *** Thread-safety requires POSIX signals, which are not supported by your
+ *** operating system.
+ " >&5
+ echo "$as_me: error:
+ *** Thread-safety requires POSIX signals, which are not supported by your
+ *** operating system.
+ " >&2;}
+ { (exit 1); exit 1; }; }
+ fi
+
if test $ac_cv_func_fseeko = yes; then
# Check whether --enable-largefile or --disable-largefile was given.
if test "${enable_largefile+set}" = set; then
Index: configure.in
===================================================================
RCS file: /cvsroot/pgsql/configure.in,v
retrieving revision 1.387
diff -c -c -r1.387 configure.in
*** configure.in 30 Nov 2004 06:13:04 -0000 1.387
--- configure.in 1 Dec 2004 22:54:11 -0000
***************
*** 1174,1179 ****
--- 1174,1186 ----
PGAC_FUNC_POSIX_SIGNALS
+ if test "$pgac_cv_func_posix_signals" != yes -a "$enable_thread_safety" = yes; then
+ AC_MSG_ERROR([
+ *** Thread-safety requires POSIX signals, which are not supported by your
+ *** operating system.
+ ])
+ fi
+
if test $ac_cv_func_fseeko = yes; then
AC_SYS_LARGEFILE
fi
Index: doc/src/sgml/libpq.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v
retrieving revision 1.169
diff -c -c -r1.169 libpq.sgml
*** doc/src/sgml/libpq.sgml 27 Nov 2004 21:56:04 -0000 1.169
--- doc/src/sgml/libpq.sgml 1 Dec 2004 22:54:45 -0000
***************
*** 3955,3975 ****
</para>
<para>
! <application>libpq</application> must ignore <literal>SIGPIPE</> signals
! generated internally by <function>send()</> calls to backend processes.
! When <productname>PostgreSQL</> is configured without
! <literal>--enable-thread-safety</>, <application>libpq</> sets
! <literal>SIGPIPE</> to <literal>SIG_IGN</> before each
! <function>send()</> call and restores the original signal handler after
! completion. When <literal>--enable-thread-safety</> is used,
! <application>libpq</> installs its own <literal>SIGPIPE</> handler
! before the first database connection. This handler uses thread-local
! storage to determine if a <literal>SIGPIPE</> signal has been generated
! by a libpq <function>send()</>. If an application wants to install
! its own <literal>SIGPIPE</> signal handler, it should call
! <function>PQinSend()</> to determine if it should ignore the
! <literal>SIGPIPE</> signal. This function is available in both
! thread-safe and non-thread-safe versions of <application>libpq</>.
</para>
<para>
--- 3955,3964 ----
</para>
<para>
! <application>libpq</application> blocks and discards <literal>SIGPIPE</>
! signals generated internally by <function>send()</> calls to the backend
! process. Therefore, applications should not expect blocked <literal>SIGPIPE</>
! signals to remain across <application>libpq</application> function calls.
</para>
<para>
Index: doc/src/sgml/ref/copy.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v
retrieving revision 1.60
diff -c -c -r1.60 copy.sgml
*** doc/src/sgml/ref/copy.sgml 27 Nov 2004 21:56:05 -0000 1.60
--- doc/src/sgml/ref/copy.sgml 1 Dec 2004 22:54:57 -0000
***************
*** 3,8 ****
--- 3,9 ----
PostgreSQL documentation
-->
+
<refentry id="SQL-COPY">
<refmeta>
<refentrytitle id="sql-copy-title">COPY</refentrytitle>
Index: src/interfaces/libpq/fe-connect.c
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v
retrieving revision 1.289
diff -c -c -r1.289 fe-connect.c
*** src/interfaces/libpq/fe-connect.c 30 Oct 2004 23:11:26 -0000 1.289
--- src/interfaces/libpq/fe-connect.c 1 Dec 2004 22:55:18 -0000
***************
*** 865,879 ****
const char *node = NULL;
int ret;
- #ifdef ENABLE_THREAD_SAFETY
- #ifndef WIN32
- static pthread_once_t check_sigpipe_once = PTHREAD_ONCE_INIT;
-
- /* Check only on first connection request */
- pthread_once(&check_sigpipe_once, pq_check_sigpipe_handler);
- #endif
- #endif
-
if (!conn)
return 0;
--- 865,870 ----
Index: src/interfaces/libpq/fe-print.c
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/libpq/fe-print.c,v
retrieving revision 1.55
diff -c -c -r1.55 fe-print.c
*** src/interfaces/libpq/fe-print.c 9 Nov 2004 15:57:57 -0000 1.55
--- src/interfaces/libpq/fe-print.c 1 Dec 2004 22:55:25 -0000
***************
*** 91,97 ****
int total_line_length = 0;
int usePipe = 0;
char *pagerenv;
!
#if !defined(ENABLE_THREAD_SAFETY) && !defined(WIN32)
pqsigfunc oldsigpipehandler = NULL;
#endif
--- 91,100 ----
int total_line_length = 0;
int usePipe = 0;
char *pagerenv;
! #ifdef ENABLE_THREAD_SAFETY
! sigset_t osigset;
! bool sigpipe_masked = false;
! #endif
#if !defined(ENABLE_THREAD_SAFETY) && !defined(WIN32)
pqsigfunc oldsigpipehandler = NULL;
#endif
***************
*** 189,195 ****
{
usePipe = 1;
#ifdef ENABLE_THREAD_SAFETY
! pthread_setspecific(pq_thread_in_send, "t");
#else
#ifndef WIN32
oldsigpipehandler = pqsignal(SIGPIPE, SIG_IGN);
--- 192,199 ----
{
usePipe = 1;
#ifdef ENABLE_THREAD_SAFETY
! pq_block_sigpipe(&osigset);
! sigpipe_masked = true;
#else
#ifndef WIN32
oldsigpipehandler = pqsignal(SIGPIPE, SIG_IGN);
***************
*** 311,317 ****
pclose(fout);
#endif
#ifdef ENABLE_THREAD_SAFETY
! pthread_setspecific(pq_thread_in_send, "f");
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsigpipehandler);
--- 315,322 ----
pclose(fout);
#endif
#ifdef ENABLE_THREAD_SAFETY
! if (sigpipe_masked)
! pq_reset_sigpipe(&osigset);
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsigpipehandler);
Index: src/interfaces/libpq/fe-secure.c
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/libpq/fe-secure.c,v
retrieving revision 1.57
diff -c -c -r1.57 fe-secure.c
*** src/interfaces/libpq/fe-secure.c 20 Nov 2004 00:35:13 -0000 1.57
--- src/interfaces/libpq/fe-secure.c 1 Dec 2004 22:55:31 -0000
***************
*** 152,163 ****
static SSL_CTX *SSL_context = NULL;
#endif
- #ifdef ENABLE_THREAD_SAFETY
- static void sigpipe_handler_ignore_send(int signo);
- pthread_key_t pq_thread_in_send = 0; /* initializer needed on Darwin */
- static pqsigfunc pq_pipe_handler;
- #endif
-
/* ------------------------------------------------------------ */
/* Hardcoded values */
/* ------------------------------------------------------------ */
--- 152,157 ----
***************
*** 379,387 ****
pqsecure_write(PGconn *conn, const void *ptr, size_t len)
{
ssize_t n;
!
#ifdef ENABLE_THREAD_SAFETY
! pthread_setspecific(pq_thread_in_send, "t");
#else
#ifndef WIN32
pqsigfunc oldsighandler = pqsignal(SIGPIPE, SIG_IGN);
--- 373,383 ----
pqsecure_write(PGconn *conn, const void *ptr, size_t len)
{
ssize_t n;
!
#ifdef ENABLE_THREAD_SAFETY
! sigset_t osigmask;
!
! pq_block_sigpipe(&osigmask);
#else
#ifndef WIN32
pqsigfunc oldsighandler = pqsignal(SIGPIPE, SIG_IGN);
***************
*** 454,460 ****
n = send(conn->sock, ptr, len, 0);
#ifdef ENABLE_THREAD_SAFETY
! pthread_setspecific(pq_thread_in_send, "f");
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsighandler);
--- 450,456 ----
n = send(conn->sock, ptr, len, 0);
#ifdef ENABLE_THREAD_SAFETY
! pq_reset_sigpipe(&osigmask);
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsighandler);
***************
*** 1216,1280 ****
}
#endif /* USE_SSL */
-
#ifdef ENABLE_THREAD_SAFETY
- #ifndef WIN32
/*
! * Check SIGPIPE handler and perhaps install our own.
*/
! void
! pq_check_sigpipe_handler(void)
{
! pthread_key_create(&pq_thread_in_send, NULL);
!
! /*
! * Find current pipe handler and chain on to it.
! */
! pq_pipe_handler = pqsignalinquire(SIGPIPE);
! pqsignal(SIGPIPE, sigpipe_handler_ignore_send);
! }
!
! /*
! * Threaded SIGPIPE signal handler
*/
! void
! sigpipe_handler_ignore_send(int signo)
{
! /*
! * If we have gotten a SIGPIPE outside send(), chain or exit if we are
! * at the end of the chain. Synchronous signals are delivered to the
! * thread that caused the signal.
! */
! if (!PQinSend())
{
! if (pq_pipe_handler == SIG_DFL) /* not set by application */
! exit(128 + SIGPIPE); /* typical return value for SIG_DFL */
! else
! (*pq_pipe_handler) (signo); /* call original handler */
}
- }
- #endif
- #endif
-
- /*
- * Indicates whether the current thread is in send()
- * For use by SIGPIPE signal handlers; they should
- * ignore SIGPIPE when libpq is in send(). This means
- * that the backend has died unexpectedly.
- */
- pqbool
- PQinSend(void)
- {
- #ifdef ENABLE_THREAD_SAFETY
- return (pthread_getspecific(pq_thread_in_send) /* has it been set? */ &&
- *(char *) pthread_getspecific(pq_thread_in_send) == 't') ? true : false;
- #else
! /*
! * No threading: our code ignores SIGPIPE around send(). Therefore, we
! * can't be in send() if we are checking from a SIGPIPE signal
! * handler.
! */
! return false;
! #endif
}
--- 1212,1264 ----
}
#endif /* USE_SSL */
#ifdef ENABLE_THREAD_SAFETY
/*
! * Block SIGPIPE for this thread. This prevents send()/write() from exiting
! * the application.
*/
! int
! pq_block_sigpipe(sigset_t *osigset)
{
! sigset_t sigpipe_sigset;
!
! sigemptyset(&sigpipe_sigset);
! sigaddset(&sigpipe_sigset, SIGPIPE);
!
! /* Block SIGPIPE and save previous mask for later reset */
! return pthread_sigmask(SIG_BLOCK, &sigpipe_sigset, osigset);
! }
!
! /*
! * Discard any pending SIGPIPE and reset the signal mask.
! * We might be discarding a blocked SIGPIPE that we didn't generate,
! * but we document that you can't keep blocked SIGPIPE calls across
! * libpq function calls.
*/
! int
! pq_reset_sigpipe(sigset_t *osigset)
{
! int signo;
! sigset_t sigset;
!
! /* Is SIGPIPE pending? */
! if (sigpending(&sigset) != 0)
! return -1;
!
! if (sigismember(&sigset, SIGPIPE))
{
! sigset_t sigpipe_sigset;
!
! sigemptyset(&sigpipe_sigset);
! sigaddset(&sigpipe_sigset, SIGPIPE);
!
! /* Discard pending and blocked SIGPIPE */
! sigwait(&sigpipe_sigset, &signo);
! if (signo != SIGPIPE)
! return -1;
}
! /* Restore saved block mask */
! return pthread_sigmask(SIG_SETMASK, osigset, NULL);
}
+ #endif
Index: src/interfaces/libpq/libpq-fe.h
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/libpq/libpq-fe.h,v
retrieving revision 1.113
diff -c -c -r1.113 libpq-fe.h
*** src/interfaces/libpq/libpq-fe.h 30 Oct 2004 23:11:27 -0000 1.113
--- src/interfaces/libpq/libpq-fe.h 1 Dec 2004 22:55:33 -0000
***************
*** 497,508 ****
/* === in fe-secure.c === */
- /*
- * Indicates whether the libpq thread is in send().
- * Used to ignore SIGPIPE if thread is in send().
- */
- extern pqbool PQinSend(void);
-
#ifdef __cplusplus
}
#endif
--- 497,502 ----
Index: src/interfaces/libpq/libpq-int.h
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/libpq/libpq-int.h,v
retrieving revision 1.96
diff -c -c -r1.96 libpq-int.h
*** src/interfaces/libpq/libpq-int.h 30 Oct 2004 23:11:27 -0000 1.96
--- src/interfaces/libpq/libpq-int.h 1 Dec 2004 22:55:35 -0000
***************
*** 31,36 ****
--- 31,37 ----
#ifdef ENABLE_THREAD_SAFETY
#include <pthread.h>
+ #include <signal.h>
#endif
#ifdef WIN32_CLIENT_ONLY
***************
*** 475,489 ****
extern ssize_t pqsecure_read(PGconn *, void *ptr, size_t len);
extern ssize_t pqsecure_write(PGconn *, const void *ptr, size_t len);
- #ifdef ENABLE_THREAD_SAFETY
- extern void pq_check_sigpipe_handler(void);
- extern pthread_key_t pq_thread_in_send;
- #endif
-
#ifdef USE_SSL
extern bool pq_initssllib;
#endif
/*
* this is so that we can check if a connection is non-blocking internally
* without the overhead of a function call
--- 476,490 ----
extern ssize_t pqsecure_read(PGconn *, void *ptr, size_t len);
extern ssize_t pqsecure_write(PGconn *, const void *ptr, size_t len);
#ifdef USE_SSL
extern bool pq_initssllib;
#endif
+ #ifdef ENABLE_THREAD_SAFETY
+ int pq_block_sigpipe(sigset_t *osigset);
+ int pq_reset_sigpipe(sigset_t *osigset);
+ #endif
+
/*
* this is so that we can check if a connection is non-blocking internally
* without the overhead of a function call
