Fix multiple bugs and infelicities in pg_rewind.

Bugs all spotted by Coverity, including wrong realloc() size request
and memory leaks.  Cosmetic improvements by me.

The usage of the global variable "filemap" here is still pretty awful,
but at least I got rid of the gratuitous aliasing in several routines
(which was helping to annoy Coverity, as well as being a bug risk).

1 files changed, 32 insertions, 28 deletions

diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c
index 4e026473066..ee6e6db9b02 100644
--- a/src/bin/pg_rewind/filemap.c
+++ b/src/bin/pg_rewind/filemap.c
@@ -30,12 +30,12 @@ static char *datasegpath(RelFileNode rnode, ForkNumber forknum,
 			BlockNumber segno);
 static int	path_cmp(const void *a, const void *b);
 static int	final_filemap_cmp(const void *a, const void *b);
-static void filemap_list_to_array(void);
+static void filemap_list_to_array(filemap_t *map);
 
 /*
- * Create a new file map.
+ * Create a new file map (stored in the global pointer "filemap").
  */
-filemap_t *
+void
 filemap_create(void)
 {
 	filemap_t  *map;
@@ -48,8 +48,6 @@ filemap_create(void)
 
 	Assert(filemap == NULL);
 	filemap = map;
-
-	return map;
 }
 
 /*
@@ -271,7 +269,10 @@ process_local_file(const char *path, file_type_t type, size_t oldsize,
 			pg_fatal("remote file list is empty\n");
 		}
 
-		filemap_list_to_array();
+		filemap_list_to_array(map);
+
+		Assert(map->array != NULL);
+
 		qsort(map->array, map->narray, sizeof(file_entry_t *), path_cmp);
 	}
 
@@ -284,8 +285,8 @@ process_local_file(const char *path, file_type_t type, size_t oldsize,
 
 	key.path = (char *) path;
 	key_ptr = &key;
-	exists = bsearch(&key_ptr, map->array, map->narray, sizeof(file_entry_t *),
-					 path_cmp) != NULL;
+	exists = (bsearch(&key_ptr, map->array, map->narray, sizeof(file_entry_t *),
+					  path_cmp) != NULL);
 
 	/* Remove any file or folder that doesn't exist in the remote system. */
 	if (!exists)
@@ -335,7 +336,7 @@ process_block_change(ForkNumber forknum, RelFileNode rnode, BlockNumber blkno)
 	filemap_t  *map = filemap;
 	file_entry_t **e;
 
-	Assert(filemap->array);
+	Assert(map->array);
 
 	segno = blkno / RELSEG_SIZE;
 	blkno_inseg = blkno % RELSEG_SIZE;
@@ -395,38 +396,40 @@ process_block_change(ForkNumber forknum, RelFileNode rnode, BlockNumber blkno)
 }
 
 /*
- * Convert the linked list of entries in filemap->first/last to the array,
- * filemap->array.
+ * Convert the linked list of entries in map->first/last to the array,
+ * map->array.
  */
 static void
-filemap_list_to_array(void)
+filemap_list_to_array(filemap_t *map)
 {
 	int			narray;
 	file_entry_t *entry,
 			   *next;
 
-	filemap->array =
-		pg_realloc(filemap->array,
-				   (filemap->nlist + filemap->narray) * sizeof(file_entry_t));
+	map->array = (file_entry_t **)
+		pg_realloc(map->array,
+				   (map->nlist + map->narray) * sizeof(file_entry_t *));
 
-	narray = filemap->narray;
-	for (entry = filemap->first; entry != NULL; entry = next)
+	narray = map->narray;
+	for (entry = map->first; entry != NULL; entry = next)
 	{
-		filemap->array[narray++] = entry;
+		map->array[narray++] = entry;
 		next = entry->next;
 		entry->next = NULL;
 	}
-	Assert(narray == filemap->nlist + filemap->narray);
-	filemap->narray = narray;
-	filemap->nlist = 0;
-	filemap->first = filemap->last = NULL;
+	Assert(narray == map->nlist + map->narray);
+	map->narray = narray;
+	map->nlist = 0;
+	map->first = map->last = NULL;
 }
 
 void
 filemap_finalize(void)
 {
-	filemap_list_to_array();
-	qsort(filemap->array, filemap->narray, sizeof(file_entry_t *),
+	filemap_t  *map = filemap;
+
+	filemap_list_to_array(map);
+	qsort(map->array, map->narray, sizeof(file_entry_t *),
 		  final_filemap_cmp);
 }
 
@@ -466,9 +469,9 @@ calculate_totals(void)
 	map->total_size = 0;
 	map->fetch_size = 0;
 
-	for (i = 0; i < filemap->narray; i++)
+	for (i = 0; i < map->narray; i++)
 	{
-		entry = filemap->array[i];
+		entry = map->array[i];
 
 		if (entry->type != FILE_TYPE_REGULAR)
 			continue;
@@ -501,12 +504,13 @@ calculate_totals(void)
 void
 print_filemap(void)
 {
+	filemap_t  *map = filemap;
 	file_entry_t *entry;
 	int			i;
 
-	for (i = 0; i < filemap->narray; i++)
+	for (i = 0; i < map->narray; i++)
 	{
-		entry = filemap->array[i];
+		entry = map->array[i];
 		if (entry->action != FILE_ACTION_NONE ||
 			entry->pagemap.bitmapsize > 0)
 		{