Fix cross-device editing failures

This resolves Bug 2215

src/libr-bfd.c

@@ -1,6 +1,7 @@
 /*
  *
  *  Copyright (c) 2008-2011 Erich Hoover
+ *  Copyright (c) 2015 Timothy Pearson <kb9vqf@pearsoncomputing.net>
  *
  *  libr libbfd Backend - Add resources into ELF binaries using libbfd
  * 
@@ -320,23 +321,36 @@ int safe_rename(const char *old, const char *new)
 {
 	char buffer[1024];
 	FILE *in, *out;
-	int read;
+	size_t read;
+	int status_in;
+	int status_out;
 	
 	in = fopen(old, "r");
-	if(!in)
+	if(!in) {
 		return -1;
+	}
 	out = fopen(new, "w");
-	if(!out)
+	if(!out) {
+		fclose(in);
 		return -1;
-	while(!feof(in) && !ferror(in))
-	{
+	}
+	while(!feof(in) && !ferror(in)) {
 		read = fread(buffer, 1, sizeof(buffer), in);
-		fwrite(buffer, read, 1, out);
+		if (read > 0) {
+			fwrite(buffer, 1, read, out);
+		}
+		if (ferror(in) || ferror(out)) {
+			fclose(in);
+			fclose(out);
+			remove(new);
+			return -1;
+		}
 	}
+	status_in = ferror(in);
+	status_out = ferror(out);
 	fclose(in);
 	fclose(out);
-	if(ferror(in))
-	{
+	if(status_in || status_out) {
 		remove(new);
 		return -1;
 	}