sed(1): Fix incomplete error message

[Michael Reed]

Hi,

I noticed that when doing `sed -i` on a file you don't have
permission to read, the error message printed isn't very helpful:

  $ sed -i '/test/d' /var/log/Xorg.1.log.old
  sed: /var/log/Xorg.1.log.old

The patch below seems to fix the issue for me:

  $ ./sed -i '/test/d' /var/log/Xorg.1.log.old
  sed: /var/log/Xorg.1.log.old: Permission denied

Regards,
  Michael



Index: main.c
===================================================================
RCS file: /cvs/src/usr.bin/sed/main.c,v
retrieving revision 1.30
diff -u -p -r1.30 main.c
--- main.c      26 Oct 2015 22:22:56 -0000      1.30
+++ main.c      1 Jan 2016 19:17:16 -0000
@@ -374,7 +374,7 @@ mf_fgets(SPACE *sp, enum e_spflag spflag
                        if (len >= sizeof(tmpfname))
                                error(FATAL, "%s: name too long", fname);
                        if ((fd = mkstemp(tmpfname)) == -1)
-                               error(FATAL, "%s", fname);
+                               error(FATAL, "%s: %s", fname, strerror(errno));
                        if ((outfile = fdopen(fd, "w")) == NULL) {
                                unlink(tmpfname);
                                error(FATAL, "%s", fname);