svn commit: r196558 - head/usr.bin/look

[Colin Percival]

Author: cperciva
Date: Wed Aug 26 03:30:06 2009
New Revision: 196558
URL: http://svn.freebsd.org/changeset/base/196558

Log:
  Don't try to mmap the contents of empty files.  This behaviour was harmless
  prior to r195693, since historical behaviour of mmap(2) was to silently
  ignore length-zero mmap requests; but mmap now returns EINVAL, which caused
  look(1) to emit an error message and fail.
  
  Among other things, this makes `freebsd-update fetch` on a newly installed
  8.0-BETA3 system print bogus warning messages.
  
  MFC after:	3 days

Modified:
  head/usr.bin/look/look.c

Modified: head/usr.bin/look/look.c
==============================================================================
--- head/usr.bin/look/look.c	Tue Aug 25 21:51:47 2009	(r196557)
+++ head/usr.bin/look/look.c	Wed Aug 26 03:30:06 2009	(r196558)
@@ -140,6 +140,10 @@ main(int argc, char *argv[])
 			err(2, "%s", file);
 		if (sb.st_size > SIZE_T_MAX)
 			errx(2, "%s: %s", file, strerror(EFBIG));
+		if (sb.st_size == 0) {
+			close(fd);
+			continue;
+		}
 		if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED)
 			err(2, "%s", file);
 		back = front + sb.st_size;