libbb: use ptsname_r, it's smaller

function                                             old     new   delta
xgetpty                                               91      81     -10
ptsname                                               33       -     -33

   text    data     bss     dec     hex filename
 793828     592    6692  801112   c3958 busybox_old
 793796     592    6660  801048   c3918 busybox_unstripped

1 files changed, 14 insertions, 10 deletions

diff --git a/libbb/getpty.c b/libbb/getpty.c
index bc143c291..4bffd9ae6 100644
--- a/libbb/getpty.c
+++ b/libbb/getpty.c
@@ -13,18 +13,26 @@
 int FAST_FUNC xgetpty(char *line)
 {
         int p;
+
 #if ENABLE_FEATURE_DEVPTS
         p = open("/dev/ptmx", O_RDWR);
         if (p > 0) {
+                grantpt(p); /* chmod+chown corresponding slave pty */
+                unlockpt(p); /* (what does this do?) */
+#if 0 /* if ptsname_r is not available... */
                 const char *name;
-                grantpt(p);
-                unlockpt(p);
-                name = ptsname(p);
+                name = ptsname(p); /* find out the name of slave pty */
                 if (!name) {
-                        bb_perror_msg("ptsname error (is /dev/pts mounted?)");
-                        goto fail;
+                        bb_perror_msg_and_die("ptsname error (is /dev/pts mounted?)");
                 }
                 safe_strncpy(line, name, GETPTY_BUFSIZE);
+#else
+                /* find out the name of slave pty */
+                if (ptsname_r(p, line, GETPTY_BUFSIZE-1) != 0) {
+                        bb_perror_msg_and_die("ptsname error (is /dev/pts mounted?)");
+                }
+                line[GETPTY_BUFSIZE-1] = '\0';
+#endif
                 return p;
         }
 #else
@@ -52,9 +60,5 @@ int FAST_FUNC xgetpty(char *line)
                 }
         }
 #endif /* FEATURE_DEVPTS */
-USE_FEATURE_DEVPTS( fail:)
-        bb_error_msg_and_die("open pty");
-        return -1; /* never get here */
+        bb_error_msg_and_die("can't find free pty");
 }
-
-