Add error-throwing wrappers for the printf family of functions.

All known standard library implementations of these functions can fail
with ENOMEM.  A caller neglecting to check for failure would experience
missing output, information exposure, or a crash.  Check return values
within wrappers and code, currently just snprintf.c, that bypasses the
wrappers.  The wrappers do not return after an error, so their callers
need not check.  Back-patch to 9.0 (all supported versions).

Popular free software standard library implementations do take pains to
bypass malloc() in simple cases, but they risk ENOMEM for floating point
numbers, positional arguments, large field widths, and large precisions.
No specification demands such caution, so this commit regards every call
to a printf family function as a potential threat.

Injecting the wrappers implicitly is a compromise between patch scope
and design goals.  I would prefer to edit each call site to name a
wrapper explicitly.  libpq and the ECPG libraries would, ideally, convey
errors to the caller rather than abort().  All that would be painfully
invasive for a back-patched security fix, hence this compromise.

Security: CVE-2015-3166

src/include/port.h

@@ -148,12 +148,11 @@ extern int	pg_strncasecmp(const char *s1, const char *s2, size_t n);
 extern unsigned char pg_toupper(unsigned char ch);
 extern unsigned char pg_tolower(unsigned char ch);
 
-#ifdef USE_REPL_SNPRINTF
-
 /*
- * Versions of libintl >= 0.13 try to replace printf() and friends with
+ * Capture macro-compatible calls to printf() and friends, and redirect them
- * macros to their own versions that understand the %$ format.  We do the
+ * to wrappers that throw errors in lieu of reporting failure in a return
- * same, so disable their macros, if they exist.
+ * value.  Versions of libintl >= 0.13 similarly redirect to versions that
+ * understand the %$ format, so disable libintl macros first.
  */
 #ifdef vsnprintf
 #undef vsnprintf
@@ -177,6 +176,55 @@ extern unsigned char pg_tolower(unsigned char ch);
 #undef printf
 #endif
 
+extern int
+vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
+__attribute__((format(printf, 3, 0)));
+extern int
+snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
+__attribute__((format(printf, 3, 4)));
+extern int
+vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
+__attribute__((format(printf, 2, 0)));
+extern int
+sprintf_throw_on_fail(char *str, const char *fmt,...)
+__attribute__((format(printf, 2, 3)));
+extern int
+vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
+__attribute__((format(printf, 2, 0)));
+extern int
+fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
+__attribute__((format(printf, 2, 3)));
+extern int
+printf_throw_on_fail(const char *fmt,...)
+__attribute__((format(printf, 1, 2)));
+
+/*
+ *	The GCC-specific code below prevents the __attribute__(... 'printf')
+ *	above from being replaced, and this is required because gcc doesn't
+ *	know anything about printf_throw_on_fail.
+ */
+#ifdef __GNUC__
+#define vsnprintf(...)	vsnprintf_throw_on_fail(__VA_ARGS__)
+#define snprintf(...)	snprintf_throw_on_fail(__VA_ARGS__)
+#define vsprintf(...)	vsprintf_throw_on_fail(__VA_ARGS__)
+#define sprintf(...)	sprintf_throw_on_fail(__VA_ARGS__)
+#define vfprintf(...)	vfprintf_throw_on_fail(__VA_ARGS__)
+#define fprintf(...)	fprintf_throw_on_fail(__VA_ARGS__)
+#define printf(...)		printf_throw_on_fail(__VA_ARGS__)
+#else
+#define vsnprintf		vsnprintf_throw_on_fail
+#define snprintf		snprintf_throw_on_fail
+#define vsprintf		vsprintf_throw_on_fail
+#define sprintf			sprintf_throw_on_fail
+#define vfprintf		vfprintf_throw_on_fail
+#define fprintf			fprintf_throw_on_fail
+#define printf			printf_throw_on_fail
+#endif
+
+#ifdef USE_REPL_SNPRINTF
+
+/* Code outside syswrap.c should not call these. */
+
 extern int	pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args);
 extern int
 pg_snprintf(char *str, size_t count, const char *fmt,...)
@@ -197,28 +245,6 @@ pg_printf(const char *fmt,...)
 /* This extension allows gcc to check the format string */
 __attribute__((format(printf, 1, 2)));
 
-/*
- *	The GCC-specific code below prevents the __attribute__(... 'printf')
- *	above from being replaced, and this is required because gcc doesn't
- *	know anything about pg_printf.
- */
-#ifdef __GNUC__
-#define vsnprintf(...)	pg_vsnprintf(__VA_ARGS__)
-#define snprintf(...)	pg_snprintf(__VA_ARGS__)
-#define vsprintf(...)	pg_vsprintf(__VA_ARGS__)
-#define sprintf(...)	pg_sprintf(__VA_ARGS__)
-#define vfprintf(...)	pg_vfprintf(__VA_ARGS__)
-#define fprintf(...)	pg_fprintf(__VA_ARGS__)
-#define printf(...)		pg_printf(__VA_ARGS__)
-#else
-#define vsnprintf		pg_vsnprintf
-#define snprintf		pg_snprintf
-#define vsprintf		pg_vsprintf
-#define sprintf			pg_sprintf
-#define vfprintf		pg_vfprintf
-#define fprintf			pg_fprintf
-#define printf			pg_printf
-#endif
 #endif   /* USE_REPL_SNPRINTF */
 
 /*

src/interfaces/ecpg/compatlib/Makefile

@@ -36,6 +36,7 @@ all: all-lib
 # Shared library stuff
 include $(top_srcdir)/src/Makefile.shlib
 
+# XXX This library uses no symbols from snprintf.c.
 snprintf.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 

src/interfaces/ecpg/ecpglib/.gitignore

@@ -6,4 +6,5 @@
 /path.c
 /pgstrcasecmp.c
 /strlcpy.c
+/syswrap.c
 /thread.c

src/interfaces/ecpg/ecpglib/Makefile

@@ -25,7 +25,7 @@ override CFLAGS += $(PTHREAD_CFLAGS)
 LIBS := $(filter-out -lpgport, $(LIBS))
 
 OBJS= execute.o typename.o descriptor.o sqlda.o data.o error.o prepare.o memory.o \
-	connect.o misc.o path.o pgstrcasecmp.o \
+	connect.o misc.o path.o pgstrcasecmp.o syswrap.o \
 	$(filter snprintf.o strlcpy.o isinf.o, $(LIBOBJS))
 
 # thread.c is needed only for non-WIN32 implementation of path.c
@@ -58,7 +58,7 @@ include $(top_srcdir)/src/Makefile.shlib
 # necessarily use the same object files as the backend uses. Instead,
 # symlink the source files in here and build our own object file.
 
-path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
+path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 misc.o: misc.c $(top_builddir)/src/port/pg_config_paths.h
@@ -75,6 +75,6 @@ uninstall: uninstall-lib
 
 clean distclean: clean-lib
 	rm -f $(OBJS)
-	rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c
+	rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c
 
 maintainer-clean: distclean maintainer-clean-lib

src/interfaces/ecpg/pgtypeslib/.gitignore

@@ -4,3 +4,4 @@
 /exports.list
 
 /pgstrcasecmp.c
+/syswrap.c

src/interfaces/ecpg/pgtypeslib/Makefile

@@ -29,7 +29,7 @@ SHLIB_LINK += -lm
 SHLIB_EXPORTS = exports.txt
 
 OBJS= numeric.o datetime.o common.o dt_common.o timestamp.o interval.o \
-	pgstrcasecmp.o \
+	pgstrcasecmp.o syswrap.o \
 	$(filter rint.o snprintf.o, $(LIBOBJS))
 
 all: all-lib
@@ -42,7 +42,7 @@ include $(top_srcdir)/src/Makefile.shlib
 # necessarily use the same object files as the backend uses. Instead,
 # symlink the source files in here and build our own object file.
 
-pgstrcasecmp.c rint.c snprintf.c: % : $(top_srcdir)/src/port/%
+pgstrcasecmp.c rint.c snprintf.c syswrap.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 install: all installdirs install-lib
@@ -52,6 +52,6 @@ installdirs: installdirs-lib
 uninstall: uninstall-lib
 
 clean distclean: clean-lib
-	rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c
+	rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c syswrap.c
 
 maintainer-clean: distclean maintainer-clean-lib

src/interfaces/libpq/.gitignore

@@ -8,6 +8,7 @@
 /snprintf.c
 /strerror.c
 /strlcpy.c
+/syswrap.c
 /thread.c
 /win32error.c
 /pgsleep.c

src/interfaces/libpq/Makefile

@@ -33,7 +33,7 @@ LIBS := $(LIBS:-lpgport=)
 OBJS=	fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
 	fe-protocol2.o fe-protocol3.o pqexpbuffer.o pqsignal.o fe-secure.o \
 	libpq-events.o \
-	md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o thread.o \
+	md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o syswrap.o thread.o \
 	$(filter crypt.o getaddrinfo.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o, $(LIBOBJS))
 
 ifeq ($(PORTNAME), cygwin)
@@ -80,7 +80,7 @@ backend_src = $(top_srcdir)/src/backend
 # For port modules, this only happens if configure decides the module
 # is needed (see filter hack in OBJS, above).
 
-crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
+crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 md5.c ip.c: % : $(backend_src)/libpq/%
@@ -133,7 +133,7 @@ ifneq (,$(findstring $(PORTNAME), win32 cygwin))
 endif
 
 clean distclean: clean-lib
-	rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
+	rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
 # Might be left over from a Win32 client-only build
 	rm -f pg_config_paths.h
 

src/interfaces/libpq/bcc32.mak

@@ -104,6 +104,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\syswrap.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
 	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -145,6 +146,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\syswrap.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\pthread-win32.obj"
 
@@ -273,6 +275,11 @@ LINK32_FLAGS = -Gn -L$(BCB)\lib;$(INTDIR); -x -Tpd -v
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
+	$(CPP) @<<
+	$(CPP_PROJ) ..\..\port\syswrap.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c

src/interfaces/libpq/win32.mak

@@ -111,6 +111,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\syswrap.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
 	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -154,6 +155,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\syswrap.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\pthread-win32.obj"
 
@@ -311,6 +313,11 @@ LINK32_OBJS= \
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
+	$(CPP) @<<
+	$(CPP_PROJ) ..\..\port\syswrap.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c

src/port/Makefile

@@ -31,7 +31,7 @@ override CPPFLAGS := -I$(top_builddir)/src/port -DFRONTEND $(CPPFLAGS)
 LIBS += $(PTHREAD_LIBS)
 
 OBJS = $(LIBOBJS) chklocale.o dirmod.o exec.o noblock.o path.o \
-	pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o thread.o
+	pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o syswrap.o thread.o
 ifneq (,$(filter $(PORTNAME),cygwin win32))
 OBJS += pipe.o
 endif

src/port/snprintf.c

@@ -114,6 +114,7 @@ typedef struct
 	/* bufend == NULL is for sprintf, where we assume buf is big enough */
 	FILE	   *stream;			/* eventual output destination, or NULL */
 	int			nchars;			/* # chars already sent to stream */
+	bool		failed;			/* call is a failure; errno is set */
 }	PrintfTarget;
 
 /*
@@ -143,7 +144,7 @@ typedef union
 
 
 static void flushbuffer(PrintfTarget * target);
-static int	dopr(PrintfTarget * target, const char *format, va_list args);
+static void dopr(PrintfTarget * target, const char *format, va_list args);
 
 
 int
@@ -157,14 +158,10 @@ pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args)
 	target.bufend = str + count - 1;
 	target.stream = NULL;
 	/* target.nchars is unused in this case */
-	if (dopr(&target, fmt, args))
+	target.failed = false;
-	{
+	dopr(&target, fmt, args);
 	*(target.bufptr) = '\0';
-		errno = EINVAL;			/* bad format */
+	return target.failed ? -1 : (target.bufptr - target.bufstart);
-		return -1;
-	}
-	*(target.bufptr) = '\0';
-	return target.bufptr - target.bufstart;
 }
 
 int
@@ -190,14 +187,10 @@ pg_vsprintf(char *str, const char *fmt, va_list args)
 	target.bufend = NULL;
 	target.stream = NULL;
 	/* target.nchars is unused in this case */
-	if (dopr(&target, fmt, args))
+	target.failed = false;
-	{
+	dopr(&target, fmt, args);
 	*(target.bufptr) = '\0';
-		errno = EINVAL;			/* bad format */
+	return target.failed ? -1 : (target.bufptr - target.bufstart);
-		return -1;
-	}
-	*(target.bufptr) = '\0';
-	return target.bufptr - target.bufstart;
 }
 
 int
@@ -227,14 +220,11 @@ pg_vfprintf(FILE *stream, const char *fmt, va_list args)
 	target.bufend = buffer + sizeof(buffer) - 1;
 	target.stream = stream;
 	target.nchars = 0;
-	if (dopr(&target, fmt, args))
+	target.failed = false;
-	{
+	dopr(&target, fmt, args);
-		errno = EINVAL;			/* bad format */
-		return -1;
-	}
 	/* dump any remaining buffer contents */
 	flushbuffer(&target);
-	return target.nchars;
+	return target.failed ? -1 : target.nchars;
 }
 
 int
@@ -261,14 +251,24 @@ pg_printf(const char *fmt,...)
 	return len;
 }
 
-/* call this only when stream is defined */
+/*
+ * Attempt to write the entire buffer to target->stream; discard the entire
+ * buffer in any case.  Call this only when target->stream is defined.
+ */
 static void
 flushbuffer(PrintfTarget * target)
 {
 	size_t		nc = target->bufptr - target->bufstart;
 
-	if (nc > 0)
+	if (!target->failed && nc > 0)
-		target->nchars += fwrite(target->bufstart, 1, nc, target->stream);
+	{
+		size_t		written;
+
+		written = fwrite(target->bufstart, 1, nc, target->stream);
+		target->nchars += written;
+		if (written != nc)
+			target->failed = true;
+	}
 	target->bufptr = target->bufstart;
 }
 
@@ -295,7 +295,7 @@ static void trailing_pad(int *padlen, PrintfTarget * target);
 /*
  * dopr(): poor man's version of doprintf
  */
-static int
+static void
 dopr(PrintfTarget * target, const char *format, va_list args)
 {
 	const char *format_start = format;
@@ -372,12 +372,12 @@ nextch1:
 			case '$':
 				have_dollar = true;
 				if (accum <= 0 || accum > NL_ARGMAX)
-					return -1;
+					goto bad_format;
 				if (afterstar)
 				{
 					if (argtypes[accum] &&
 						argtypes[accum] != ATYPE_INT)
-						return -1;
+						goto bad_format;
 					argtypes[accum] = ATYPE_INT;
 					last_dollar = Max(last_dollar, accum);
 					afterstar = false;
@@ -414,7 +414,7 @@ nextch1:
 						atype = ATYPE_INT;
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != atype)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = atype;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -426,7 +426,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_INT)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_INT;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -439,7 +439,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_CHARPTR)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_CHARPTR;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -455,7 +455,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_DOUBLE)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_DOUBLE;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -476,7 +476,7 @@ nextch1:
 
 	/* Per spec, you use either all dollar or all not. */
 	if (have_dollar && have_non_dollar)
-		return -1;
+		goto bad_format;
 
 	/*
 	 * In dollar mode, collect the arguments in physical order.
@@ -486,7 +486,7 @@ nextch1:
 		switch (argtypes[i])
 		{
 			case ATYPE_NONE:
-				return -1;		/* invalid format */
+				goto bad_format;
 			case ATYPE_INT:
 				argvalues[i].i = va_arg(args, int);
 				break;
@@ -511,6 +511,9 @@ nextch1:
 	format = format_start;
 	while ((ch = *format++) != '\0')
 	{
+		if (target->failed)
+			break;
+
 		if (ch != '%')
 		{
 			dopr_outch(ch, target);
@@ -755,7 +758,11 @@ nextch2:
 		}
 	}
 
-	return 0;
+	return;
+
+bad_format:
+	errno = EINVAL;
+	target->failed = true;
 }
 
 static size_t
@@ -805,7 +812,9 @@ fmtptr(void *value, PrintfTarget * target)
 
 	/* we rely on regular C library's sprintf to do the basic conversion */
 	vallen = sprintf(convert, "%p", value);
-
+	if (vallen < 0)
+		target->failed = true;
+	else
 		dostr(convert, vallen, target);
 }
 
@@ -939,16 +948,19 @@ fmtfloat(double value, char type, int forcesign, int leftjust,
 
 	if (pointflag)
 	{
-		sprintf(fmt, "%%.%d%c", prec, type);
+		if (sprintf(fmt, "%%.%d%c", prec, type) < 0)
+			goto fail;
 		zeropadlen = precision - prec;
 	}
-	else
+	else if (sprintf(fmt, "%%%c", type) < 0)
-		sprintf(fmt, "%%%c", type);
+		goto fail;
 
 	if (!isnan(value) && adjust_sign((value < 0), forcesign, &signvalue))
 		value = -value;
 
 	vallen = sprintf(convert, fmt, value);
+	if (vallen < 0)
+		goto fail;
 
 	/* If it's infinity or NaN, forget about doing any zero-padding */
 	if (zeropadlen > 0 && !isdigit((unsigned char) convert[vallen - 1]))
@@ -988,6 +1000,10 @@ fmtfloat(double value, char type, int forcesign, int leftjust,
 	}
 
 	trailing_pad(&padlen, target);
+	return;
+
+fail:
+	target->failed = true;
 }
 
 static void

src/port/syswrap.c

@@ -0,0 +1,155 @@
+/*-------------------------------------------------------------------------
+ *
+ * syswrap.c
+ *	  error-throwing wrappers around POSIX functions that rarely fail
+ *
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/port/syswrap.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef FRONTEND
+#include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
+
+/* Prevent recursion */
+#undef	vsnprintf
+#undef	snprintf
+#undef	vsprintf
+#undef	sprintf
+#undef	vfprintf
+#undef	fprintf
+#undef	printf
+
+/* When the libc primitives are lacking, use our own. */
+#ifdef USE_REPL_SNPRINTF
+#ifdef __GNUC__
+#define vsnprintf(...)	pg_vsnprintf(__VA_ARGS__)
+#define snprintf(...)	pg_snprintf(__VA_ARGS__)
+#define vsprintf(...)	pg_vsprintf(__VA_ARGS__)
+#define sprintf(...)	pg_sprintf(__VA_ARGS__)
+#define vfprintf(...)	pg_vfprintf(__VA_ARGS__)
+#define fprintf(...)	pg_fprintf(__VA_ARGS__)
+#define printf(...)		pg_printf(__VA_ARGS__)
+#else
+#define vsnprintf		pg_vsnprintf
+#define snprintf		pg_snprintf
+#define vsprintf		pg_vsprintf
+#define sprintf			pg_sprintf
+#define vfprintf		pg_vfprintf
+#define fprintf			pg_fprintf
+#define printf			pg_printf
+#endif
+#endif   /* USE_REPL_SNPRINTF */
+
+/*
+ * We abort() in the frontend, rather than exit(), because libpq in particular
+ * has no business calling exit().  These failures had better be rare.
+ */
+#ifdef FRONTEND
+#define LIB_ERR(func) \
+do { \
+	int discard = fprintf(stderr, "%s failed: %s\n", func, strerror(errno)); \
+	(void) discard; \
+	abort(); \
+} while (0)
+#else
+#define LIB_ERR(func) elog(ERROR, "%s failed: %m", func)
+#endif
+
+int
+vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
+{
+	int			save_errno;
+	int			ret;
+
+	/*
+	 * On HP-UX B.11.31, a call that truncates output returns -1 without
+	 * setting errno.  (SUSv2 allowed this until the approval of Base Working
+	 * Group Resolution BWG98-006.)  We could avoid the save and restore of
+	 * errno on most platforms.
+	 */
+	save_errno = errno;
+	errno = 0;
+	ret = vsnprintf(str, count, fmt, args);
+	if (ret < 0 && errno != 0)
+		LIB_ERR("vsnprintf");
+	errno = save_errno;
+	return ret;
+}
+
+int
+snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vsnprintf_throw_on_fail(str, count, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
+{
+	int			ret;
+
+	ret = vsprintf(str, fmt, args);
+	if (ret < 0)
+		LIB_ERR("vsprintf");
+	return ret;
+}
+
+int
+sprintf_throw_on_fail(char *str, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vsprintf_throw_on_fail(str, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
+{
+	int			ret;
+
+	ret = vfprintf(stream, fmt, args);
+	if (ret < 0)
+		LIB_ERR("vfprintf");
+	return ret;
+}
+
+int
+fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vfprintf_throw_on_fail(stream, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+printf_throw_on_fail(const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vfprintf_throw_on_fail(stdout, fmt, args);
+	va_end(args);
+	return ret;
+}

src/tools/msvc/Mkvcbuild.pm

@@ -52,7 +52,7 @@ sub mkvcbuild
       chklocale.c crypt.c fseeko.c getrusage.c inet_aton.c random.c srandom.c
       getaddrinfo.c gettimeofday.c kill.c open.c erand48.c mkdtemp.c
       snprintf.c strlcat.c strlcpy.c dirmod.c exec.c noblock.c path.c pipe.c
-      pgsleep.c pgstrcasecmp.c qsort.c qsort_arg.c sprompt.c thread.c
+      pgsleep.c pgstrcasecmp.c qsort.c qsort_arg.c sprompt.c syswrap.c thread.c
       getopt.c getopt_long.c dirent.c rint.c win32env.c win32error.c);
 
     $libpgport = $solution->AddProject('libpgport','lib','misc');