- pmap->pm_prog = MOUNTPROG;
- pmap->pm_vers = MOUNTVERS_NFSV3;
- if (opts && (p = strstr(opts, "mountprog=")) && isdigit(*(p+10)))
- pmap->pm_prog = atoi(p+10);
- if (opts && (p = strstr(opts, "mountport=")) && isdigit(*(p+10)))
- pmap->pm_port = atoi(p+10);
- if (opts && hasmntopt(&mnt, "v2"))
- pmap->pm_vers = nfsvers_to_mnt(2);
- if (opts && hasmntopt(&mnt, "v3"))
- pmap->pm_vers = nfsvers_to_mnt(3);
- if (opts && hasmntopt(&mnt, "v4"))
- pmap->pm_vers = nfsvers_to_mnt(4);
- if (opts && (p = strstr(opts, "vers=")) && isdigit(*(p+5)))
- pmap->pm_vers = nfsvers_to_mnt(atoi(p+5));
- if (opts && (p = strstr(opts, "mountvers=")) && isdigit(*(p+10)))
- pmap->pm_vers = atoi(p+10);
- if (opts && (hasmntopt(&mnt, "udp") || hasmntopt(&mnt, "proto=udp")))
- pmap->pm_prot = IPPROTO_UDP;
-
- if (!nfs_gethostbyname(hostname, &mnt_server.saddr)) {
- nfs_error(_("%s: '%s' does not contain a recognized hostname"),
- progname, spec);
- return EX_USAGE;
+/*
+ * Detect NFSv4 mounts.
+ *
+ * Consult /proc/mounts to determine if the mount point
+ * is an NFSv4 mount. The kernel is authoritative about
+ * what type of mount this is.
+ *
+ * Returns 1 if "mc" is an NFSv4 mount, zero if not, and
+ * -1 if some error occurred.
+ */
+static int nfs_umount_is_vers4(const struct mntentchn *mc)
+{
+ char buffer[LINELEN], *next;
+ int retval;
+ FILE *f;
+
+ if ((f = fopen(MOUNTSFILE, "r")) == NULL) {
+ fprintf(stderr, "%s: %s\n",
+ MOUNTSFILE, strerror(errno));
+ return -1;