fuser(1) needs pledge("proc") to send signals

[Theo Buehler]

I noticed a number of "fuser(PID): syscall 37" entries in my dmesg.
If 'sflg' is set (i.e., the -k or -s options were specified),
fuser might call kill(2) (see fuser.c: 176), otherwise "stdio rpath"
is apparently sufficient for fuser.

Index: usr.bin/fstat/fstat.c
===================================================================
RCS file: /cvs/src/usr.bin/fstat/fstat.c,v
retrieving revision 1.81
diff -u -p -r1.81 fstat.c
--- usr.bin/fstat/fstat.c       10 Oct 2015 14:29:05 -0000      1.81
+++ usr.bin/fstat/fstat.c       12 Oct 2015 10:47:19 -0000
@@ -275,8 +275,18 @@ main(int argc, char *argv[])
        if ((kf = kvm_getfiles(kd, what, arg, sizeof(*kf), &cnt)) == NULL)
                errx(1, "%s", kvm_geterr(kd));
 
-       if (pledge("stdio rpath route", NULL) == -1)
-               err(1, "pledge");
+       if (fuser) {
+               if (sflg) { /* fuser might call kill(2) */
+                       if (pledge("stdio rpath proc", NULL) == -1)
+                               err(1, "pledge");
+               } else {
+                       if (pledge("stdio rpath", NULL) == -1)
+                               err(1, "pledge");
+               }
+       } else {
+               if (pledge("stdio rpath route", NULL) == -1)
+                       err(1, "pledge");
+       }
 
        find_splices(kf, cnt);
        if (!fuser)