Fix handling of array of char pointers in ecpglib.

Michael Meskes · Michael Meskes · commit 8d6a07fa01ce · 2014-05-06T13:09:51.000+02:00
When array of char * was used as target for a FETCH statement returning more
than one row, it tried to store all the result in the first element. Instead it
should dump array of char pointers with right offset, use the address instead
of the value of the C variable while reading the array and treat such variable
as char **, instead of char * for pointer arithmetic.

Patch by Ashutosh Bapat &lt;ashutosh.bapat@enterprisedb.com&gt;
diff --git a/src/interfaces/ecpg/ecpglib/data.c b/src/interfaces/ecpg/ecpglib/data.c
@@ -455,6 +455,14 @@ ecpg_get_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 					{
 						char	   *str = (char *) (var + offset * act_tuple);
 
+						/*
+						 * If varcharsize is unknown and the offset is that of
+						 * char *, then this variable represents the array of
+						 * character pointers. So, use extra indirection.
+						 */
+						if (varcharsize == 0 && offset == sizeof(char *))
+							str = *(char **)str;
+
 						if (varcharsize == 0 || varcharsize > size)
 						{
 							strncpy(str, pval, size + 1);
diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c
@@ -1930,7 +1930,14 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator,
 			var->arrsize = va_arg(args, long);
 			var->offset = va_arg(args, long);
 
-			if (var->arrsize == 0 || var->varcharsize == 0)
+			/* 
+			 * Unknown array size means pointer to an array.
+			 * Unknown varcharsize usually also means pointer. But if the
+			 * type is character and the array size is known, it is an
+			 * array of pointers to char, so use var->pointer as it is.
+			 */
+			if (var->arrsize == 0 ||
+			    (var->varcharsize == 0 && ((var->type != ECPGt_char && var->type != ECPGt_unsigned_char) || (var->arrsize <= 1))))
 				var->value = *((char **) (var->pointer));
 			else
 				var->value = var->pointer;
diff --git a/src/interfaces/ecpg/preproc/type.c b/src/interfaces/ecpg/preproc/type.c
@@ -448,7 +448,8 @@ ECPGdump_a_simple(FILE *o, const char *name, enum ECPGttype type,
 			case ECPGt_unsigned_char:
 			case ECPGt_char_variable:
 			case ECPGt_string:
-
+			{
+				char	*sizeof_name = "char";
 				/*
 				 * we have to use the pointer except for arrays with given
 				 * bounds, ecpglib will distinguish between * and []
@@ -458,12 +459,24 @@ ECPGdump_a_simple(FILE *o, const char *name, enum ECPGttype type,
 				 (atoi(varcharsize) == 0 && strcmp(varcharsize, "0") != 0) ||
 					 (atoi(arrsize) == 0 && strcmp(arrsize, "0") != 0))
 					&& siz == NULL)
+				{
 					sprintf(variable, "(%s%s)", prefix ? prefix : "", name);
+					if ((type == ECPGt_char || type == ECPGt_unsigned_char) &&
+						strcmp(varcharsize, "0") == 0)
+					{
+						/*
+						 * If this is an array of char *, the offset would be
+						 * sizeof(char *) and not sizeof(char).
+						 */
+						sizeof_name = "char *";
+					}
+				}
 				else
 					sprintf(variable, "&(%s%s)", prefix ? prefix : "", name);
 
-				sprintf(offset, "(%s)*sizeof(char)", strcmp(varcharsize, "0") == 0 ? "1" : varcharsize);
+				sprintf(offset, "(%s)*sizeof(%s)", strcmp(varcharsize, "0") == 0 ? "1" : varcharsize, sizeof_name);
 				break;
+			}
 			case ECPGt_numeric:
 
 				/*

Original file line number	Diff line number	Diff line change
`@@ -455,6 +455,14 @@ ecpg_get_data(const PGresult *results, int act_tuple, int act_field, int lineno,`
`455`	`455`	`{`
`456`	`456`	`char str = (char ) (var + offset * act_tuple);`
`457`	`457`
	`458`	`+ /*`
	`459`	`+ * If varcharsize is unknown and the offset is that of`
	`460`	`+ * char *, then this variable represents the array of`
	`461`	`+ * character pointers. So, use extra indirection.`
	`462`	`+ */`
	`463`	`+ if (varcharsize == 0 && offset == sizeof(char *))`
	`464`	`+ str = (char *)str;`
	`465`	`+`
`458`	`466`	`if (varcharsize == 0 \|\| varcharsize > size)`
`459`	`467`	`{`
`460`	`468`	`strncpy(str, pval, size + 1);`