Fix incorrect message-printing in win32security.c.

log_error() would probably fail completely if used, and would
certainly print garbage for anything that needed to be interpolated
into the message, because it was failing to use the correct printing
subroutine for a va_list argument.

This bug likely went undetected because the error cases this code
is used for are rarely exercised - they only occur when Windows
security API calls fail catastrophically (out of memory, security
subsystem corruption, etc).

The FRONTEND variant can be fixed just by calling vfprintf()
instead of fprintf().  However, there was no va_list variant
of write_stderr(), so create one by refactoring that function.
Following the usual naming convention for such things, call
it vwrite_stderr().

Author: Bryan Green <[email protected]>
Reviewed-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/CAF+pBj8goe4fRmZ0V3Cs6eyWzYLvK+HvFLYEYWG=TzaM+tWPnw@mail.gmail.com
Backpatch-through: 13

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 648d2d2e70c9f0b455e956450a369a4309ae798f..29643c51439e0396936e29baf5816262be1706ad 100644 (file)
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -3795,13 +3795,24 @@ write_stderr(const char *fmt,...)
 {
    va_list     ap;
 
+   va_start(ap, fmt);
+   vwrite_stderr(fmt, ap);
+   va_end(ap);
+}
+
+
+/*
+ * Write errors to stderr (or by equal means when stderr is
+ * not available) - va_list version
+ */
+void
+vwrite_stderr(const char *fmt, va_list ap)
+{
 #ifdef WIN32
    char        errbuf[2048];   /* Arbitrary size? */
 #endif
 
    fmt = _(fmt);
-
-   va_start(ap, fmt);
 #ifndef WIN32
    /* On Unix, we just fprintf to stderr */
    vfprintf(stderr, fmt, ap);
@@ -3824,5 +3835,4 @@ write_stderr(const char *fmt,...)
        fflush(stderr);
    }
 #endif
-   va_end(ap);
 }

diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 348dafbf90622ec08174160b97794f66ca46e972..001ab93ae6c0ecfa23c24a1e2f9d2e54e0c4a7bd 100644 (file)
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -528,5 +528,6 @@ extern void write_jsonlog(ErrorData *edata);
  * safely (memory context, GUC load etc)
  */
 extern void write_stderr(const char *fmt,...) pg_attribute_printf(1, 2);
+extern void vwrite_stderr(const char *fmt, va_list ap) pg_attribute_printf(1, 0);
 
 #endif                         /* ELOG_H */

diff --git a/src/port/win32security.c b/src/port/win32security.c
index a46b82dd0482b15f670781a5c32739ea2446e9dd..b7608ab1706226d1173b11213846517b4a10d154 100644 (file)
--- a/src/port/win32security.c
+++ b/src/port/win32security.c
@@ -31,9 +31,9 @@ log_error(const char *fmt,...)
 
    va_start(ap, fmt);
 #ifndef FRONTEND
-   write_stderr(fmt, ap);
+   vwrite_stderr(fmt, ap);
 #else
-   fprintf(stderr, fmt, ap);
+   vfprintf(stderr, fmt, ap);
 #endif
    va_end(ap);
 }