From 5d7a555d0f42bce2a3ac05ea4fc32e6781803f1f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 2 Dec 2004 23:20:21 +0000
Subject: [PATCH] Code review for recent libpq changes. Be more careful about
error handling in SIGPIPE processing; avoid unnecessary pollution of
application link-symbol namespace; spell 'pointer to function' in the
conventional way.
---
src/interfaces/libpq/fe-connect.c | 31 +++++------
src/interfaces/libpq/fe-print.c | 9 ++--
src/interfaces/libpq/fe-secure.c | 87 ++++++++++++++++++++-----------
src/interfaces/libpq/libpq-fe.h | 13 +++--
src/interfaces/libpq/libpq-int.h | 21 ++++----
5 files changed, 90 insertions(+), 71 deletions(-)
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 30e56b4b6eb..57d7ee8e6ff 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.291 2004/12/02 15:32:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.292 2004/12/02 23:20:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -202,6 +202,11 @@ static int parseServiceInfo(PQconninfoOption *options,
static char *pwdfMatchesString(char *buf, char *token);
static char *PasswordFromFile(char *hostname, char *port, char *dbname,
char *username);
+static void default_threadlock(int acquire);
+
+
+/* global variable because fe-auth.c needs to access it */
+pgthreadlock_t pg_g_threadlock = default_threadlock;
/*
@@ -3276,16 +3281,6 @@ PasswordFromFile(char *hostname, char *port, char *dbname, char *username)
* if they are not required.
*/
-void
-PQinitSSL(int do_init)
-{
-#ifdef USE_SSL
- pq_initssllib = do_init;
-#endif
-}
-
-static pgthreadlock_t default_threadlock;
-
static void
default_threadlock(int acquire)
{
@@ -3313,17 +3308,15 @@ default_threadlock(int acquire)
#endif
}
-pgthreadlock_t *g_threadlock = default_threadlock;
-
-pgthreadlock_t *
-PQregisterThreadLock(pgthreadlock_t *newhandler)
+pgthreadlock_t
+PQregisterThreadLock(pgthreadlock_t newhandler)
{
- pgthreadlock_t *prev;
+ pgthreadlock_t prev = pg_g_threadlock;
- prev = g_threadlock;
if (newhandler)
- g_threadlock = newhandler;
+ pg_g_threadlock = newhandler;
else
- g_threadlock = default_threadlock;
+ pg_g_threadlock = default_threadlock;
+
return prev;
}
diff --git a/src/interfaces/libpq/fe-print.c b/src/interfaces/libpq/fe-print.c
index 9992de533d7..8c2ce003ac8 100644
--- a/src/interfaces/libpq/fe-print.c
+++ b/src/interfaces/libpq/fe-print.c
@@ -10,7 +10,7 @@
* didn't really belong there.
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-print.c,v 1.56 2004/12/02 15:32:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-print.c,v 1.57 2004/12/02 23:20:20 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -193,8 +193,8 @@ PQprint(FILE *fout,
{
usePipe = 1;
#ifdef ENABLE_THREAD_SAFETY
- pq_block_sigpipe(&osigset, &sigpipe_pending);
- sigpipe_masked = true;
+ if (pq_block_sigpipe(&osigset, &sigpipe_pending) == 0)
+ sigpipe_masked = true;
#else
#ifndef WIN32
oldsigpipehandler = pqsignal(SIGPIPE, SIG_IGN);
@@ -316,8 +316,9 @@ PQprint(FILE *fout,
pclose(fout);
#endif
#ifdef ENABLE_THREAD_SAFETY
+ /* we can't easily verify if EPIPE occurred, so say it did */
if (sigpipe_masked)
- pq_reset_sigpipe(&osigset, sigpipe_pending);
+ pq_reset_sigpipe(&osigset, sigpipe_pending, true);
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsigpipehandler);
diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index 79ea192f99c..a40b92065b9 100644
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.58 2004/12/02 15:32:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/fe-secure.c,v 1.59 2004/12/02 23:20:21 tgl Exp $
*
* NOTES
* [ Most of these notes are wrong/obsolete, but perhaps not all ]
@@ -147,7 +147,7 @@ static void SSLerrfree(char *buf);
#endif
#ifdef USE_SSL
-bool pq_initssllib = true;
+static bool pq_initssllib = true;
static SSL_CTX *SSL_context = NULL;
#endif
@@ -212,6 +212,19 @@ KWbuHn491xNO25CQWMtem80uKw+pTnisBRF/454n1Jnhub144YRBoN8CAQI=\n\
/* Procedures common to all secure sessions */
/* ------------------------------------------------------------ */
+
+/*
+ * Exported (but as yet undocumented) function to allow application to
+ * tell us it's already initialized OpenSSL.
+ */
+void
+PQinitSSL(int do_init)
+{
+#ifdef USE_SSL
+ pq_initssllib = do_init;
+#endif
+}
+
/*
* Initialize global context
*/
@@ -377,8 +390,10 @@ pqsecure_write(PGconn *conn, const void *ptr, size_t len)
#ifdef ENABLE_THREAD_SAFETY
sigset_t osigmask;
bool sigpipe_pending;
+ bool got_epipe = false;
- pq_block_sigpipe(&osigmask, &sigpipe_pending);
+ if (pq_block_sigpipe(&osigmask, &sigpipe_pending) < 0)
+ return -1;
#else
#ifndef WIN32
pqsigfunc oldsighandler = pqsignal(SIGPIPE, SIG_IGN);
@@ -413,9 +428,13 @@ pqsecure_write(PGconn *conn, const void *ptr, size_t len)
char sebuf[256];
if (n == -1)
+ {
+ if (SOCK_ERRNO == EPIPE)
+ got_epipe = true;
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSL SYSCALL error: %s\n"),
SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
+ }
else
{
printfPQExpBuffer(&conn->errorMessage,
@@ -448,15 +467,16 @@ pqsecure_write(PGconn *conn, const void *ptr, size_t len)
}
else
#endif
+ {
n = send(conn->sock, ptr, len, 0);
- /*
- * Possible optimization: if sigpending() turns out to be an
- * expensive operation, we can set sigpipe_pending = 'true'
- * here if errno != EPIPE, avoiding a sigpending call.
- */
+#ifdef ENABLE_THREAD_SAFETY
+ if (n < 0 && SOCK_ERRNO == EPIPE)
+ got_epipe = true;
+#endif
+ }
#ifdef ENABLE_THREAD_SAFETY
- pq_reset_sigpipe(&osigmask, sigpipe_pending);
+ pq_reset_sigpipe(&osigmask, sigpipe_pending, got_epipe);
#else
#ifndef WIN32
pqsignal(SIGPIPE, oldsighandler);
@@ -1228,13 +1248,14 @@ pq_block_sigpipe(sigset_t *osigset, bool *sigpipe_pending)
{
sigset_t sigpipe_sigset;
sigset_t sigset;
- int ret;
sigemptyset(&sigpipe_sigset);
sigaddset(&sigpipe_sigset, SIGPIPE);
/* Block SIGPIPE and save previous mask for later reset */
- ret = pthread_sigmask(SIG_BLOCK, &sigpipe_sigset, osigset);
+ SOCK_ERRNO_SET(pthread_sigmask(SIG_BLOCK, &sigpipe_sigset, osigset));
+ if (SOCK_ERRNO)
+ return -1;
/* We can have a pending SIGPIPE only if it was blocked before */
if (sigismember(osigset, SIGPIPE))
@@ -1251,44 +1272,52 @@ pq_block_sigpipe(sigset_t *osigset, bool *sigpipe_pending)
else
*sigpipe_pending = false;
- return ret;
+ return 0;
}
/*
* 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.
+ *
+ * Note: we are effectively assuming here that the C library doesn't queue
+ * up multiple SIGPIPE events. If it did, then we'd accidentally leave
+ * ours in the queue when an event was already pending and we got another.
+ * As long as it doesn't queue multiple events, we're OK because the caller
+ * can't tell the difference.
+ *
+ * The caller should say got_epipe = FALSE if it is certain that it
+ * didn't get an EPIPE error; in that case we'll skip the clear operation
+ * and things are definitely OK, queuing or no. If it got one or might have
+ * gotten one, pass got_epipe = TRUE.
+ *
+ * We do not want this to change errno, since if it did that could lose
+ * the error code from a preceding send(). We essentially assume that if
+ * we were able to do pq_block_sigpipe(), this can't fail.
*/
-int
-pq_reset_sigpipe(sigset_t *osigset, bool sigpipe_pending)
+void
+pq_reset_sigpipe(sigset_t *osigset, bool sigpipe_pending, bool got_epipe)
{
+ int save_errno = SOCK_ERRNO;
int signo;
sigset_t sigset;
/* Clear SIGPIPE only if none was pending */
- if (!sigpipe_pending)
+ if (got_epipe && !sigpipe_pending)
{
- if (sigpending(&sigset) != 0)
- return -1;
-
- /*
- * Discard pending and blocked SIGPIPE
- */
- if (sigismember(&sigset, SIGPIPE))
+ if (sigpending(&sigset) == 0 &&
+ sigismember(&sigset, SIGPIPE))
{
sigset_t sigpipe_sigset;
sigemptyset(&sigpipe_sigset);
sigaddset(&sigpipe_sigset, SIGPIPE);
-
+
sigwait(&sigpipe_sigset, &signo);
- if (signo != SIGPIPE)
- return -1;
}
}
/* Restore saved block mask */
- return pthread_sigmask(SIG_SETMASK, osigset, NULL);
+ pthread_sigmask(SIG_SETMASK, osigset, NULL);
+
+ SOCK_ERRNO_SET(save_errno);
}
#endif
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index b472a1ae81c..638c27542c3 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.114 2004/12/02 15:32:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.115 2004/12/02 23:20:21 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -279,6 +279,9 @@ extern SSL *PQgetssl(PGconn *conn);
extern void *PQgetssl(PGconn *conn);
#endif
+/* Tell libpq whether it needs to initialize OpenSSL */
+extern void PQinitSSL(int do_init);
+
/* Set verbosity for PQerrorMessage and PQresultErrorMessage */
extern PGVerbosity PQsetErrorVerbosity(PGconn *conn, PGVerbosity verbosity);
@@ -301,11 +304,9 @@ extern PQnoticeProcessor PQsetNoticeProcessor(PGconn *conn,
* Only required for multithreaded apps that use kerberos
* both within their app and for postgresql connections.
*/
-typedef void (pgthreadlock_t) (int acquire);
+typedef void (*pgthreadlock_t) (int acquire);
-extern pgthreadlock_t *PQregisterThreadLock(pgthreadlock_t *newhandler);
-
-extern void PQinitSSL(int do_init);
+extern pgthreadlock_t PQregisterThreadLock(pgthreadlock_t newhandler);
/* === in fe-exec.c === */
@@ -495,8 +496,6 @@ extern int PQdsplen(const unsigned char *s, int encoding);
/* Get encoding id from environment variable PGCLIENTENCODING */
extern int PQenv2encoding(void);
-/* === in fe-secure.c === */
-
#ifdef __cplusplus
}
#endif
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 13b7e3588ce..7657b364a50 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -12,7 +12,7 @@
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.97 2004/12/02 15:32:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.98 2004/12/02 23:20:21 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -379,13 +379,13 @@ extern int pqPacketSend(PGconn *conn, char pack_type,
const void *buf, size_t buf_len);
#ifdef ENABLE_THREAD_SAFETY
-extern pgthreadlock_t *g_threadlock;
+extern pgthreadlock_t pg_g_threadlock;
-#define pglock_thread() g_threadlock(true);
-#define pgunlock_thread() g_threadlock(false);
+#define pglock_thread() pg_g_threadlock(true)
+#define pgunlock_thread() pg_g_threadlock(false)
#else
-#define pglock_thread() ((void)0)
-#define pgunlock_thread() ((void)0)
+#define pglock_thread() ((void) 0)
+#define pgunlock_thread() ((void) 0)
#endif
@@ -476,13 +476,10 @@ extern void pqsecure_close(PGconn *);
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, bool *sigpipe_pending);
-int pq_reset_sigpipe(sigset_t *osigset, bool sigpipe_pending);
+extern int pq_block_sigpipe(sigset_t *osigset, bool *sigpipe_pending);
+extern void pq_reset_sigpipe(sigset_t *osigset, bool sigpipe_pending,
+ bool got_epipe);
#endif
/*
--
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