mmap diff for patch(1)

[Michael W. Bombardieri]

Hi tech,

I have a diff for the patch(1) tool which copies
one included in NetBSD two years ago...

Source: NetBSD src/usr.bin/patch/inp.c revision 1.23
Purpose: Don't bother mmap'ing an empty file

Comments/OK?

- Michael


Index: inp.c
===================================================================
RCS file: /usr/src/cvs/src/usr.bin/patch/inp.c,v
retrieving revision 1.35
diff -u -r1.35 inp.c
--- inp.c       27 Oct 2009 23:59:41 -0000      1.35
+++ inp.c       11 Nov 2011 03:12:10 -0000
@@ -243,12 +243,16 @@
        if ((ifd = open(filename, O_RDONLY)) < 0)
                pfatal("can't open file %s", filename);
 
-       i_womp = mmap(NULL, i_size, PROT_READ, MAP_PRIVATE, ifd, 0);
-       if (i_womp == MAP_FAILED) {
-               perror("mmap failed");
+       if (i_size == 0)
                i_womp = NULL;
-               close(ifd);
-               return false;
+       else {
+               i_womp = mmap(NULL, i_size, PROT_READ, MAP_PRIVATE, ifd, 0);
+               if (i_womp == MAP_FAILED) {
+                       perror("mmap failed");
+                       i_womp = NULL;
+                       close(ifd);
+                       return false;
+               }
        }
 
        close(ifd);