Fix a couple of memory leaks in src/bin/pg_basebackup/

These have been introduced by 7fbe0c8, and could happen for
pg_basebackup and pg_receivewal.

Per report from Coverity for the ones in walmethods.c, I have spotted
the ones in receivelog.c after more review.

Backpatch-through: 10

Author: michaelpq

src/bin/pg_basebackup/receivelog.c

@@ -117,6 +117,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 		{
 			pg_log_error("could not get size of write-ahead log file \"%s\": %s",
 						 fn, stream->walmethod->getlasterror());
+			pg_free(fn);
 			return false;
 		}
 		if (size == WalSegSz)
@@ -127,6 +128,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 			{
 				pg_log_error("could not open existing write-ahead log file \"%s\": %s",
 							 fn, stream->walmethod->getlasterror());
+				pg_free(fn);
 				return false;
 			}
 
@@ -140,6 +142,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 			}
 
 			walfile = f;
+			pg_free(fn);
 			return true;
 		}
 		if (size != 0)
@@ -151,6 +154,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 								  "write-ahead log file \"%s\" has %d bytes, should be 0 or %d",
 								  size),
 						 fn, (int) size, WalSegSz);
+			pg_free(fn);
 			return false;
 		}
 		/* File existed and was empty, so fall through and open */
@@ -164,9 +168,11 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 	{
 		pg_log_error("could not open write-ahead log file \"%s\": %s",
 					 fn, stream->walmethod->getlasterror());
+		pg_free(fn);
 		return false;
 	}
 
+	pg_free(fn);
 	walfile = f;
 	return true;
 }

src/bin/pg_basebackup/walmethods.c

@@ -94,6 +94,7 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 	filename = dir_get_file_name(pathname, temp_suffix);
 	snprintf(tmppath, sizeof(tmppath), "%s/%s",
 			 dir_data->basedir, filename);
+	pg_free(filename);
 
 	/*
 	 * Open a file for non-compressed as well as compressed files. Tracking
@@ -254,11 +255,13 @@ dir_close(Walfile f, WalCloseMethod method)
 			filename = dir_get_file_name(df->pathname, df->temp_suffix);
 			snprintf(tmppath, sizeof(tmppath), "%s/%s",
 					 dir_data->basedir, filename);
+			pg_free(filename);
 
 			/* permanent name, so no need for the prefix */
 			filename2 = dir_get_file_name(df->pathname, NULL);
 			snprintf(tmppath2, sizeof(tmppath2), "%s/%s",
 					 dir_data->basedir, filename2);
+			pg_free(filename2);
 			r = durable_rename(tmppath, tmppath2);
 		}
 		else if (method == CLOSE_UNLINK)
@@ -269,6 +272,7 @@ dir_close(Walfile f, WalCloseMethod method)
 			filename = dir_get_file_name(df->pathname, df->temp_suffix);
 			snprintf(tmppath, sizeof(tmppath), "%s/%s",
 					 dir_data->basedir, filename);
+			pg_free(filename);
 			r = unlink(tmppath);
 		}
 		else
@@ -625,11 +629,14 @@ tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 	if (tarCreateHeader(tar_data->currentfile->header, tmppath, NULL, 0, S_IRUSR | S_IWUSR, 0, 0, time(NULL)) != TAR_OK)
 	{
 		pg_free(tar_data->currentfile);
+		pg_free(tmppath);
 		tar_data->currentfile = NULL;
 		tar_set_error("could not create tar header");
 		return NULL;
 	}
 
+	pg_free(tmppath);
+
 #ifdef HAVE_LIBZ
 	if (tar_data->compression)
 	{

src/bin/pg_basebackup/walmethods.h

@@ -53,8 +53,8 @@ struct WalWriteMethod
 	ssize_t		(*get_file_size) (const char *pathname);
 
 	/*
-	 * Return the name of the current file to work on, without the base
-	 * directory.  This is useful for logging.
+	 * Return the name of the current file to work on in pg_malloc()'d string,
+	 * without the base directory.  This is useful for logging.
 	 */
 	char	   *(*get_file_name) (const char *pathname, const char *temp_suffix);