Fix more format truncation issues

Fix the warnings created by the compiler warning options
-Wformat-overflow=2 -Wformat-truncation=2, supported since GCC 7.  This
is a more aggressive variant of the fixes in
6275f5d28a1577563f53f2171689d4f890a46881, which GCC 7 warned about by
default.

The issues are all harmless, but some dubious coding patterns are
cleaned up.

One issue that is of external interest is that BGW_MAXLEN is increased
from 64 to 96.  Apparently, the old value would cause the bgw_name of
logical replication workers to be truncated in some circumstances.

But this doesn't actually add those warning options.  It appears that
the warnings depend a bit on compilation and optimization options, so it
would be annoying to have to keep up with that.  This is more of a
once-in-a-while cleanup.

Reviewed-by: Michael Paquier <michael@paquier.xyz>

6 files changed, 27 insertions, 43 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 900fa74e85..f0dfef5a86 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -3337,10 +3337,11 @@ void
 ExplainPropertyFloat(const char *qlabel, double value, int ndigits,
 					 ExplainState *es)
 {
-	char		buf[256];
+	char	   *buf;
 
-	snprintf(buf, sizeof(buf), "%.*f", ndigits, value);
+	buf = psprintf("%.*f", ndigits, value);
 	ExplainProperty(qlabel, buf, true, es);
+	pfree(buf);
 }
 
 /*
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index e1ddfb3c16..567cf7d455 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -1013,7 +1013,7 @@ static const char *
 SSLerrmessage(unsigned long ecode)
 {
 	const char *errreason;
-	static char errbuf[32];
+	static char errbuf[36];
 
 	if (ecode == 0)
 		return _("no SSL error reported");
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 834a10485f..07e5e78caa 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -86,7 +86,7 @@ calculate_database_size(Oid dbOid)
 	DIR		   *dirdesc;
 	struct dirent *direntry;
 	char		dirpath[MAXPGPATH];
-	char		pathname[MAXPGPATH + 12 + sizeof(TABLESPACE_VERSION_DIRECTORY)];
+	char		pathname[MAXPGPATH + 21 + sizeof(TABLESPACE_VERSION_DIRECTORY)];
 	AclResult	aclresult;
 
 	/*
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index aadb92de66..6522c0816e 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -44,10 +44,6 @@ static const uint32 nan[2] = {0xffffffff, 0x7fffffff};
 #define NAN (*(const double *) nan)
 #endif
 
-/* not sure what the following should be, but better to make it over-sufficient */
-#define MAXFLOATWIDTH	64
-#define MAXDOUBLEWIDTH	128
-
 /*
  * check to see if a float4/8 val has underflowed or overflowed
  */
@@ -360,18 +356,18 @@ Datum
 float4out(PG_FUNCTION_ARGS)
 {
 	float4		num = PG_GETARG_FLOAT4(0);
-	char	   *ascii = (char *) palloc(MAXFLOATWIDTH + 1);
+	char	   *ascii;
 
 	if (isnan(num))
-		PG_RETURN_CSTRING(strcpy(ascii, "NaN"));
+		PG_RETURN_CSTRING(pstrdup("NaN"));
 
 	switch (is_infinite(num))
 	{
 		case 1:
-			strcpy(ascii, "Infinity");
+			ascii = pstrdup("Infinity");
 			break;
 		case -1:
-			strcpy(ascii, "-Infinity");
+			ascii = pstrdup("-Infinity");
 			break;
 		default:
 			{
@@ -380,7 +376,7 @@ float4out(PG_FUNCTION_ARGS)
 				if (ndig < 1)
 					ndig = 1;
 
-				snprintf(ascii, MAXFLOATWIDTH + 1, "%.*g", ndig, num);
+				ascii = psprintf("%.*g", ndig, num);
 			}
 	}
 
@@ -596,18 +592,18 @@ float8out(PG_FUNCTION_ARGS)
 char *
 float8out_internal(double num)
 {
-	char	   *ascii = (char *) palloc(MAXDOUBLEWIDTH + 1);
+	char	   *ascii;
 
 	if (isnan(num))
-		return strcpy(ascii, "NaN");
+		return pstrdup("NaN");
 
 	switch (is_infinite(num))
 	{
 		case 1:
-			strcpy(ascii, "Infinity");
+			ascii = pstrdup("Infinity");
 			break;
 		case -1:
-			strcpy(ascii, "-Infinity");
+			ascii = pstrdup("-Infinity");
 			break;
 		default:
 			{
@@ -616,7 +612,7 @@ float8out_internal(double num)
 				if (ndig < 1)
 					ndig = 1;
 
-				snprintf(ascii, MAXDOUBLEWIDTH + 1, "%.*g", ndig, num);
+				ascii = psprintf("%.*g", ndig, num);
 			}
 	}
 
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index b8bd4caa3e..1a1088711c 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -117,13 +117,6 @@
 #define DCH_MAX_ITEM_SIZ	   12	/* max localized day name		*/
 #define NUM_MAX_ITEM_SIZ		8	/* roman number (RN has 15 chars)	*/
 
-/* ----------
- * More is in float.c
- * ----------
- */
-#define MAXFLOATWIDTH	60
-#define MAXDOUBLEWIDTH	500
-
 
 /* ----------
  * Format parser structs
@@ -3911,9 +3904,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			tmfc.tzm < 0 || tmfc.tzm >= MINS_PER_HOUR)
 			DateTimeParseError(DTERR_TZDISP_OVERFLOW, date_str, "timestamp");
 
-		tz = palloc(7);
-
-		snprintf(tz, 7, "%c%02d:%02d",
+		tz = psprintf("%c%02d:%02d",
 				 tmfc.tzsign > 0 ? '+' : '-', tmfc.tzh, tmfc.tzm);
 
 		tm->tm_zone = tz;
@@ -4135,7 +4126,7 @@ int_to_roman(int number)
 				num = 0;
 	char	   *p = NULL,
 			   *result,
-				numstr[5];
+				numstr[12];
 
 	result = (char *) palloc(16);
 	*result = '\0';
@@ -5441,8 +5432,7 @@ int4_to_char(PG_FUNCTION_ARGS)
 		/* we can do it easily because float8 won't lose any precision */
 		float8		val = (float8) value;
 
-		orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
-		snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, val);
+		orgnum = (char *) psprintf("%+.*e", Num.post, val);
 
 		/*
 		 * Swap a leading positive sign for a space.
@@ -5641,7 +5631,6 @@ float4_to_char(PG_FUNCTION_ARGS)
 		numstr = orgnum = int_to_roman((int) rint(value));
 	else if (IS_EEEE(&Num))
 	{
-		numstr = orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
 		if (isnan(value) || is_infinite(value))
 		{
 			/*
@@ -5655,7 +5644,7 @@ float4_to_char(PG_FUNCTION_ARGS)
 		}
 		else
 		{
-			snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, value);
+			numstr = orgnum = psprintf("%+.*e", Num.post, value);
 
 			/*
 			 * Swap a leading positive sign for a space.
@@ -5679,8 +5668,7 @@ float4_to_char(PG_FUNCTION_ARGS)
 			Num.pre += Num.multi;
 		}
 
-		orgnum = (char *) palloc(MAXFLOATWIDTH + 1);
-		snprintf(orgnum, MAXFLOATWIDTH + 1, "%.0f", fabs(val));
+		orgnum = (char *) psprintf("%.0f", fabs(val));
 		numstr_pre_len = strlen(orgnum);
 
 		/* adjust post digits to fit max float digits */
@@ -5688,7 +5676,7 @@ float4_to_char(PG_FUNCTION_ARGS)
 			Num.post = 0;
 		else if (numstr_pre_len + Num.post > FLT_DIG)
 			Num.post = FLT_DIG - numstr_pre_len;
-		snprintf(orgnum, MAXFLOATWIDTH + 1, "%.*f", Num.post, val);
+		orgnum = psprintf("%.*f", Num.post, val);
 
 		if (*orgnum == '-')
 		{						/* < 0 */
@@ -5747,7 +5735,6 @@ float8_to_char(PG_FUNCTION_ARGS)
 		numstr = orgnum = int_to_roman((int) rint(value));
 	else if (IS_EEEE(&Num))
 	{
-		numstr = orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
 		if (isnan(value) || is_infinite(value))
 		{
 			/*
@@ -5761,7 +5748,7 @@ float8_to_char(PG_FUNCTION_ARGS)
 		}
 		else
 		{
-			snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, value);
+			numstr = orgnum = (char *) psprintf("%+.*e", Num.post, value);
 
 			/*
 			 * Swap a leading positive sign for a space.
@@ -5784,15 +5771,15 @@ float8_to_char(PG_FUNCTION_ARGS)
 			val = value * multi;
 			Num.pre += Num.multi;
 		}
-		orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
-		numstr_pre_len = snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%.0f", fabs(val));
+		orgnum = psprintf("%.0f", fabs(val));
+		numstr_pre_len = strlen(orgnum);
 
 		/* adjust post digits to fit max double digits */
 		if (numstr_pre_len >= DBL_DIG)
 			Num.post = 0;
 		else if (numstr_pre_len + Num.post > DBL_DIG)
 			Num.post = DBL_DIG - numstr_pre_len;
-		snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%.*f", Num.post, val);
+		orgnum = psprintf("%.*f", Num.post, val);
 
 		if (*orgnum == '-')
 		{						/* < 0 */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fc3e10c750..4116c2d66a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10528,7 +10528,7 @@ check_cluster_name(char **newval, void **extra, GucSource source)
 static const char *
 show_unix_socket_permissions(void)
 {
-	static char buf[8];
+	static char buf[12];
 
 	snprintf(buf, sizeof(buf), "%04o", Unix_socket_permissions);
 	return buf;
@@ -10537,7 +10537,7 @@ show_unix_socket_permissions(void)
 static const char *
 show_log_file_mode(void)
 {
-	static char buf[8];
+	static char buf[12];
 
 	snprintf(buf, sizeof(buf), "%04o", Log_file_mode);
 	return buf;