enable tame(2) in who(1).

some refactor to grab ttyname(0) early and use it later.
gradually drop tame requests when no more needed.

"ioctl" is used for grab ttyname(0)
"rpath" is for -T and -u flag, that used stat(2) to get terminal status

initial patch from deraadt with help from guenther

ok deraadt@

diff --git a/usr.bin/who/who.c b/usr.bin/who/who.c
index 3506aff..63dc95c 100644 (file)
--- a/usr.bin/who/who.c
+++ b/usr.bin/who/who.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: who.c,v 1.20 2013/08/22 04:43:41 guenther Exp $       */
+/*     $OpenBSD: who.c,v 1.21 2015/10/07 16:11:40 semarie Exp $        */
 /*     $NetBSD: who.c,v 1.4 1994/12/07 04:28:49 jtc Exp $      */
 
 /*
@@ -62,16 +62,26 @@ int show_quick;                     /* quick, names only */
 #define HOST_WIDTH     45
 
 int hostwidth = HOST_WIDTH;
+char *mytty;
 
 int
 main(int argc, char *argv[])
 {
        struct utmp usr;
        FILE *ufp;
+       char *t;
        int c;
 
        setlocale(LC_ALL, "");
 
+       if (tame("stdio getpw rpath ioctl", NULL) == -1)
+               err(1, "tame");
+
+       mytty = ttyname(0);
+       /* strip any directory component */
+       if ((t = strrchr(mytty, '/')))
+               mytty = t + 1;
+
        only_current_term = show_term = show_idle = show_labels = 0;
        show_quick = 0;
        while ((c = getopt(argc, argv, "HmqTu")) != -1) {
@@ -179,21 +189,16 @@ who_am_i(FILE *ufp)
 {
        struct utmp usr;
        struct passwd *pw;
-       char *p;
-       char *t;
 
        /* search through the utmp and find an entry for this tty */
-       if ((p = ttyname(0))) {
-               /* strip any directory component */
-               if ((t = strrchr(p, '/')))
-                       p = t + 1;
+       if (mytty) {
                while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
-                       if (*usr.ut_name && !strcmp(usr.ut_line, p)) {
+                       if (*usr.ut_name && !strcmp(usr.ut_line, mytty)) {
                                output(&usr);
                                return;
                        }
                /* well, at least we know what the tty is */
-               (void)strncpy(usr.ut_line, p, UT_LINESIZE);
+               (void)strncpy(usr.ut_line, mytty, UT_LINESIZE);
        } else
                (void)strncpy(usr.ut_line, "tty??", UT_LINESIZE);
 
@@ -284,6 +289,13 @@ file(char *name)
                err(1, "%s", name);
                /* NOTREACHED */
        }
+       if (show_term || show_idle) {
+               if (tame("stdio getpw rpath", NULL) == -1)
+                       err(1, "tame");
+       } else {
+               if (tame("stdio getpw", NULL) == -1)
+                       err(1, "tame");
+       }
        return(ufp);
 }