+/*
+ * options_for_tty - See if an options file exists for the serial
+ * device, and if so, interpret options from it.
+ */
+int
+options_for_tty()
+{
+ char *dev, *path;
+ int ret;
+
+ dev = strrchr(devname, '/');
+ if (dev == NULL)
+ dev = devname;
+ else
+ ++dev;
+ if (strcmp(dev, "tty") == 0)
+ return 1; /* don't look for /etc/ppp/options.tty */
+ path = malloc(strlen(_PATH_TTYOPT) + strlen(dev) + 1);
+ if (path == NULL)
+ novm("tty init file name");
+ strcpy(path, _PATH_TTYOPT);
+ strcat(path, dev);
+ ret = options_from_file(path, 0, 0);
+ free(path);
+ return ret;
+}
+
+/*
+ * readable - check if a file is readable by the real user.
+ */
+static int
+readable(fd)
+ int fd;
+{
+ uid_t uid;
+ int ngroups, i;
+ struct stat sbuf;
+ GETGROUPS_TYPE groups[NGROUPS_MAX];
+
+ uid = getuid();
+ if (uid == 0)
+ return 1;
+ if (fstat(fd, &sbuf) != 0)
+ return 0;
+ if (sbuf.st_uid == uid)
+ return sbuf.st_mode & S_IRUSR;
+ if (sbuf.st_gid == getgid())
+ return sbuf.st_mode & S_IRGRP;
+ ngroups = getgroups(NGROUPS_MAX, groups);
+ for (i = 0; i < ngroups; ++i)
+ if (sbuf.st_gid == groups[i])
+ return sbuf.st_mode & S_IRGRP;
+ return sbuf.st_mode & S_IROTH;
+}
+