From: Wayne Davison <wayne@opencoder.net>
Date: Mon, 6 Jul 2020 00:04:37 +0000 (-0700)
Subject: Some C99 flexible array changes
X-Git-Tag: v3.2.3pre1~135
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e1e4ffe057346de61972b2d995ebc9c720a7d8bd;p=thirdparty%2Frsync.git

Some C99 flexible array changes

- Use C99 flexible arrays when possible, and fall back on the existing
  fname[1] kluges on older compilers.
- Avoid static initialization of a flexible array, which is not really
  in the C standard.
---

diff --git a/flist.c b/flist.c
index f248e29b..5970ce54 100644
--- a/flist.c
+++ b/flist.c
@@ -1892,7 +1892,7 @@ static void send_implied_dirs(int f, struct file_list *flist, char *fname,
 		memcpy(F_DIR_RELNAMES_P(lastpath_struct), &relname_list, sizeof relname_list);
 	}
 	rnpp = EXPAND_ITEM_LIST(relname_list, relnamecache *, 32);
-	*rnpp = (relnamecache*)new_array(char, sizeof (relnamecache) + len);
+	*rnpp = (relnamecache*)new_array(char, RELNAMECACHE_LEN + len + 1);
 	(*rnpp)->name_type = name_type;
 	strlcpy((*rnpp)->fname, limit+1, len + 1);
 
@@ -2051,8 +2051,7 @@ void send_extra_file_list(int f, int at_least)
 
 		if (need_unsorted_flist) {
 			flist->sorted = new_array(struct file_struct *, flist->used);
-			memcpy(flist->sorted, flist->files,
-			       flist->used * sizeof (struct file_struct*));
+			memcpy(flist->sorted, flist->files, flist->used * PTR_SIZE);
 		} else
 			flist->sorted = flist->files;
 
@@ -2405,8 +2404,7 @@ struct file_list *send_file_list(int f, int argc, char *argv[])
 	 * send them together in a single file-list. */
 	if (need_unsorted_flist) {
 		flist->sorted = new_array(struct file_struct *, flist->used);
-		memcpy(flist->sorted, flist->files,
-		       flist->used * sizeof (struct file_struct*));
+		memcpy(flist->sorted, flist->files, flist->used * PTR_SIZE);
 	} else
 		flist->sorted = flist->files;
 	flist_sort_and_clean(flist, 0);
@@ -2587,8 +2585,7 @@ struct file_list *recv_file_list(int f, int dir_ndx)
 		 * list unsorted for our exchange of index numbers with the
 		 * other side (since their names may not sort the same). */
 		flist->sorted = new_array(struct file_struct *, flist->used);
-		memcpy(flist->sorted, flist->files,
-		       flist->used * sizeof (struct file_struct*));
+		memcpy(flist->sorted, flist->files, flist->used * PTR_SIZE);
 		if (inc_recurse && dir_flist->used > dstart) {
 			static int dir_flist_malloced = 0;
 			if (dir_flist_malloced < dir_flist->malloced) {
@@ -2598,7 +2595,7 @@ struct file_list *recv_file_list(int f, int dir_ndx)
 				dir_flist_malloced = dir_flist->malloced;
 			}
 			memcpy(dir_flist->sorted + dstart, dir_flist->files + dstart,
-			       (dir_flist->used - dstart) * sizeof (struct file_struct*));
+			       (dir_flist->used - dstart) * PTR_SIZE);
 			fsort(dir_flist->sorted + dstart, dir_flist->used - dstart);
 		}
 	} else {
diff --git a/rsync.h b/rsync.h
index 41c4052b..1d6b8179 100644
--- a/rsync.h
+++ b/rsync.h
@@ -732,6 +732,10 @@ struct ht_int64_node {
 # error Character pointers are not 4 or 8 bytes.
 #endif
 
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+#define USE_FLEXIBLE_ARRAY 1
+#endif
+
 union file_extras {
 	int32 num;
 	uint32 unum;
@@ -753,7 +757,11 @@ struct file_struct {
 	uint32 len32;		/* Lowest 32 bits of the file's length */
 	uint16 mode;		/* The item's type and permissions */
 	uint16 flags;		/* The FLAG_* bits for this item */
-	const char basename[1];	/* The basename (AKA filename) follows */
+#ifdef USE_FLEXIBLE_ARRAY
+	const char basename[];	/* The basename (AKA filename) follows */
+#else
+	const char basename[1];	/* A kluge that should work like a flexible array */
+#endif
 };
 
 extern int file_extra_cnt;
@@ -766,7 +774,11 @@ extern int gid_ndx;
 extern int acls_ndx;
 extern int xattrs_ndx;
 
+#ifdef USE_FLEXIBLE_ARRAY
+#define FILE_STRUCT_LEN (sizeof (struct file_struct))
+#else
 #define FILE_STRUCT_LEN (offsetof(struct file_struct, basename))
+#endif
 #define EXTRA_LEN (sizeof (union file_extras))
 #define DEV_EXTRA_CNT 2
 #define DIRNODE_EXTRA_CNT 3
@@ -1035,9 +1047,19 @@ typedef struct {
 
 typedef struct {
 	char name_type;
-	char fname[1]; /* has variable size */
+#ifdef USE_FLEXIBLE_ARRAY
+	char fname[]; /* has variable size */
+#else
+	char fname[1]; /* A kluge that should work like a flexible array */
+#endif
 } relnamecache;
 
+#ifdef USE_FLEXIBLE_ARRAY
+#define RELNAMECACHE_LEN (sizeof (relnamecache))
+#else
+#define RELNAMECACHE_LEN (offsetof(relnamecache, fname))
+#endif
+
 #include "byteorder.h"
 #include "lib/mdigest.h"
 #include "lib/wildmatch.h"
@@ -1094,7 +1116,7 @@ struct name_num_obj {
 	uchar *saw;
 	int saw_len;
 	int negotiated_num;
-	struct name_num_item list[];
+	struct name_num_item list[8]; /* A big-enough len (we'll get a compile error if it is ever too small) */
 };
 
 #ifndef __cplusplus