[patch] Modify checking read ELF header file condition in ldd.c

[Nan Xiao]

Hi tech@,

I think check the actual read ELF header file size is better than just
"<0", thanks!

Best Reagrds
Nan Xiao
Index: ldd.c
===================================================================
RCS file: /cvs/src/libexec/ld.so/ldd/ldd.c,v
retrieving revision 1.21
diff -u -p -r1.21 ldd.c
--- ldd.c       2 Jul 2017 19:06:12 -0000       1.21
+++ ldd.c       4 Oct 2017 03:05:11 -0000
@@ -117,7 +117,7 @@ doit(char *name)
                close(fd);
                return 1;
        }
-       if (read(fd, &ehdr, sizeof(ehdr)) < 0) {
+       if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) {
                warn("read(%s)", name);
                close(fd);
                return 1;