attempt to regularize atoi mess.
[oweals/busybox.git] / util-linux / mount.c
index 43856eace36fa07043ddde90fa911248c1dad994..531fb4520932d6736ec99d3861112d33c0d6c19e 100644 (file)
  * Mini mount implementation for busybox
  *
  * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
- * Copyright (C) 1999-2003 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+/* Design notes: There is no spec for mount.  Remind me to write one.
+
+   mount_main() calls singlemount() which calls mount_it_now().
+
+   mount_main() can loop through /etc/fstab for mount -a
+   singlemount() can loop through /etc/filesystems for fstype detection.
+   mount_it_now() does the actual mount.
+*/
+
+#include "busybox.h"
+#include <mntent.h>
+
+/* Needed for nfs support only... */
+#include <syslog.h>
+#include <sys/utsname.h>
+#undef TRUE
+#undef FALSE
+#include <rpc/rpc.h>
+#include <rpc/pmap_prot.h>
+#include <rpc/pmap_clnt.h>
+
+
+// Not real flags, but we want to be able to check for this.
+#define MOUNT_NOAUTO    (1<<29)
+#define MOUNT_SWAP      (1<<30)
+
+/* Standard mount options (from -o options or --options), with corresponding
+ * flags */
+
+struct {
+       char *name;
+       long flags;
+} static mount_options[] = {
+       // MS_FLAGS set a bit.  ~MS_FLAGS disable that bit.  0 flags are NOPs.
+
+       USE_FEATURE_MOUNT_LOOP(
+               {"loop", 0},
+       )
+
+       USE_FEATURE_MOUNT_FSTAB(
+               {"defaults", 0},
+               {"quiet", 0},
+               {"noauto",MOUNT_NOAUTO},
+               {"swap",MOUNT_SWAP},
+       )
+
+       USE_FEATURE_MOUNT_FLAGS(
+               // vfs flags
+               {"nosuid", MS_NOSUID},
+               {"suid", ~MS_NOSUID},
+               {"dev", ~MS_NODEV},
+               {"nodev", MS_NODEV},
+               {"exec", ~MS_NOEXEC},
+               {"noexec", MS_NOEXEC},
+               {"sync", MS_SYNCHRONOUS},
+               {"async", ~MS_SYNCHRONOUS},
+               {"atime", ~MS_NOATIME},
+               {"noatime", MS_NOATIME},
+               {"diratime", ~MS_NODIRATIME},
+               {"nodiratime", MS_NODIRATIME},
+               {"loud", ~MS_SILENT},
+
+               // action flags
+
+               {"bind", MS_BIND},
+               {"move", MS_MOVE},
+               {"shared", MS_SHARED},
+               {"slave", MS_SLAVE},
+               {"private", MS_PRIVATE},
+               {"unbindable", MS_UNBINDABLE},
+               {"rshared", MS_SHARED|MS_RECURSIVE},
+               {"rslave", MS_SLAVE|MS_RECURSIVE},
+               {"rprivate", MS_SLAVE|MS_RECURSIVE},
+               {"runbindable", MS_UNBINDABLE|MS_RECURSIVE},
+       )
+
+       // Always understood.
+
+       {"ro", MS_RDONLY},        // vfs flag
+       {"rw", ~MS_RDONLY},       // vfs flag
+       {"remount", MS_REMOUNT},  // action flag
+};
+
+#define VECTOR_SIZE(v) (sizeof(v) / sizeof((v)[0]))
+
+/* Append mount options to string */
+static void append_mount_options(char **oldopts, char *newopts)
+{
+       if (*oldopts && **oldopts) {
+               /* do not insert options which are already there */
+               while (newopts[0]) {
+                       char *p;
+                       int len = strlen(newopts);
+                       p = strchr(newopts, ',');
+                       if (p) len = p - newopts;
+                       p = *oldopts;
+                       while (1) {
+                               if (!strncmp(p,newopts,len) && (p[len]==',' || p[len]==0))
+                                       goto skip;
+                               p = strchr(p,',');
+                               if(!p) break;
+                               p++;
+                       }
+                       p = xasprintf("%s,%.*s", *oldopts, len, newopts);
+                       free(*oldopts);
+                       *oldopts = p;
+skip:
+                       newopts += len;
+                       while (newopts[0] == ',') newopts++;
+               }
+       } else {
+               if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
+               *oldopts = xstrdup(newopts);
+       }
+}
+
+/* Use the mount_options list to parse options into flags.
+ * Also return list of unrecognized options if unrecognized!=NULL */
+static int parse_mount_options(char *options, char **unrecognized)
+{
+       int flags = MS_SILENT;
+
+       // Loop through options
+       for (;;) {
+               int i;
+               char *comma = strchr(options, ',');
+
+               if (comma) *comma = 0;
+
+               // Find this option in mount_options
+               for (i = 0; i < VECTOR_SIZE(mount_options); i++) {
+                       if (!strcasecmp(mount_options[i].name, options)) {
+                               long fl = mount_options[i].flags;
+                               if (fl < 0) flags &= fl;
+                               else flags |= fl;
+                               break;
+                       }
+               }
+               // If unrecognized not NULL, append unrecognized mount options */
+               if (unrecognized && i == VECTOR_SIZE(mount_options)) {
+                       // Add it to strflags, to pass on to kernel
+                       i = *unrecognized ? strlen(*unrecognized) : 0;
+                       *unrecognized = xrealloc(*unrecognized, i+strlen(options)+2);
+
+                       // Comma separated if it's not the first one
+                       if (i) (*unrecognized)[i++] = ',';
+                       strcpy((*unrecognized)+i, options);
+               }
+
+               // Advance to next option, or finish
+               if (comma) {
+                       *comma = ',';
+                       options = ++comma;
+               } else break;
+       }
+
+       return flags;
+}
+
+// Return a list of all block device backed filesystems
+
+static llist_t *get_block_backed_filesystems(void)
+{
+       char *fs, *buf,
+                *filesystems[] = {"/etc/filesystems", "/proc/filesystems", 0};
+       llist_t *list = 0;
+       int i;
+       FILE *f;
+
+       for (i = 0; filesystems[i]; i++) {
+               f = fopen(filesystems[i], "r");
+               if (!f) continue;
+
+               for (fs = buf = 0; (fs = buf = bb_get_chomped_line_from_file(f));
+                       free(buf))
+               {
+                       if (!strncmp(buf,"nodev",5) && isspace(buf[5])) continue;
+
+                       while (isspace(*fs)) fs++;
+                       if (*fs=='#' || *fs=='*') continue;
+                       if (!*fs) continue;
+
+                       llist_add_to_end(&list,xstrdup(fs));
+               }
+               if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
+       }
+
+       return list;
+}
+
+llist_t *fslist = 0;
+
+#if ENABLE_FEATURE_CLEAN_UP
+static void delete_block_backed_filesystems(void)
+{
+       llist_free(fslist, free);
+}
+#else
+void delete_block_backed_filesystems(void);
+#endif
+
+#if ENABLE_FEATURE_MTAB_SUPPORT
+static int useMtab = 1;
+static int fakeIt;
+#else
+#define useMtab 0
+#define fakeIt 0
+#endif
+
+// Perform actual mount of specific filesystem at specific location.
+// NB: mp->xxx fields may be trashed on exit
+static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
+{
+       int rc = 0;
+
+       if (fakeIt) goto mtab;
+
+       // Mount, with fallback to read-only if necessary.
+
+       for (;;) {
+               rc = mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
+                               vfsflags, filteropts);
+               if (!rc || (vfsflags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
+                       break;
+               bb_error_msg("%s is write-protected, mounting read-only",
+                               mp->mnt_fsname);
+               vfsflags |= MS_RDONLY;
+       }
+
+       // Abort entirely if permission denied.
+
+       if (rc && errno == EPERM)
+               bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+
+       /* If the mount was successful, and we're maintaining an old-style
+        * mtab file by hand, add the new entry to it now. */
+mtab:
+       if (ENABLE_FEATURE_MTAB_SUPPORT && useMtab && !rc && !(vfsflags & MS_REMOUNT)) {
+               char *fsname;
+               FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
+               int i;
+
+               if (!mountTable)
+                       bb_error_msg("no %s",bb_path_mtab_file);
+
+               // Add vfs string flags
+
+               for (i=0; mount_options[i].flags != MS_REMOUNT; i++)
+                       if (mount_options[i].flags > 0 && (mount_options[i].flags & vfsflags))
+                               append_mount_options(&(mp->mnt_opts), mount_options[i].name);
+
+               // Remove trailing / (if any) from directory we mounted on
+
+               i = strlen(mp->mnt_dir) - 1;
+               if (i > 0 && mp->mnt_dir[i] == '/') mp->mnt_dir[i] = 0;
+
+               // Convert to canonical pathnames as needed
+
+               mp->mnt_dir = bb_simplify_path(mp->mnt_dir);
+               fsname = 0;
+               if (!mp->mnt_type || !*mp->mnt_type) { /* bind mount */
+                       mp->mnt_fsname = fsname = bb_simplify_path(mp->mnt_fsname);
+                       mp->mnt_type = "bind";
+               }
+               mp->mnt_freq = mp->mnt_passno = 0;
+
+               // Write and close.
+
+               addmntent(mountTable, mp);
+               endmntent(mountTable);
+               if (ENABLE_FEATURE_CLEAN_UP) {
+                       free(mp->mnt_dir);
+                       free(fsname);
+               }
+       }
+
+       return rc;
+}
+
+#if ENABLE_FEATURE_MOUNT_NFS
+
+/*
+ * Linux NFS mount
+ * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
  *
- * 3/21/1999   Charles P. Wright <cpwright@cpwright.com>
- *             searches through fstab when -a is passed
- *             will try mounting stuff with all fses when passed -t auto
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
  *
- * 1999-04-17  Dave Cinege...Rewrote -t auto. Fixed ro mtab.
+ * Wed Feb  8 12:51:48 1995, biro@yggdrasil.com (Ross Biro): allow all port
+ * numbers to be specified on the command line.
  *
- * 1999-10-07  Erik Andersen <andersen@codepoet.org>.
- *              Rewrite of a lot of code. Removed mtab usage (I plan on
- *              putting it back as a compile-time option some time), 
- *              major adjustments to option parsing, and some serious 
- *              dieting all around.
+ * Fri, 8 Mar 1996 18:01:39, Swen Thuemmler <swen@uni-paderborn.de>:
+ * Omit the call to connect() for Linux version 1.3.11 or later.
  *
- * 1999-11-06  mtab suppport is back - andersee
+ * Wed Oct  1 23:55:28 1997: Dick Streefland <dick_streefland@tasking.com>
+ * Implemented the "bg", "fg" and "retry" mount options for NFS.
  *
- * 2000-01-12   Ben Collins <bcollins@debian.org>, Borrowed utils-linux's
- *              mount to add loop support.
+ * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
+ * - added Native Language Support
  *
- * 2000-04-30  Dave Cinege <dcinege@psychosis.com>
- *             Rewrote fstab while loop and lower mount section. Can now do
- *             single mounts from fstab. Can override fstab options for single
- *             mount. Common mount_one call for single mounts and 'all'. Fixed
- *             mtab updating and stale entries. Removed 'remount' default. 
- *     
+ * Modified by Olaf Kirch and Trond Myklebust for new NFS code,
+ * plus NFSv3 stuff.
  */
 
-#include <limits.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <stdio.h>
-#include <mntent.h>
-#include <ctype.h>
-#include "busybox.h"
-
-#ifdef CONFIG_NFSMOUNT
+/* This is just a warning of a common mistake.  Possibly this should be a
+ * uclibc faq entry rather than in busybox... */
 #if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
-#error "You need to build uClibc with UCLIBC_HAS_RPC for busybox mount with NFS support to compile."
-#endif
+#error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support."
 #endif
 
-enum {
-       MS_MGC_VAL = 0xc0ed0000,        /* Magic number indicatng "new" flags */
-       MS_RDONLY = 1,          /* Mount read-only */
-       MS_NOSUID = 2,          /* Ignore suid and sgid bits */
-       MS_NODEV = 4,           /* Disallow access to device special files */
-       MS_NOEXEC = 8,          /* Disallow program execution */
-       MS_SYNCHRONOUS = 16,    /* Writes are synced at once */
-       MS_REMOUNT = 32,        /* Alter flags of a mounted FS */
-       MS_MANDLOCK = 64,       /* Allow mandatory locks on an FS */
-       S_QUOTA = 128,          /* Quota initialized for file/directory/symlink */
-       S_APPEND = 256,         /* Append-only file */
-       S_IMMUTABLE = 512,      /* Immutable file */
-       MS_NOATIME = 1024,      /* Do not update access times. */
-       MS_NODIRATIME = 2048,   /* Do not update directory access times */
-       MS_BIND = 4096,         /* Use the new linux 2.4.x "mount --bind" feature */
+#define MOUNTPORT 635
+#define MNTPATHLEN 1024
+#define MNTNAMLEN 255
+#define FHSIZE 32
+#define FHSIZE3 64
+
+typedef char fhandle[FHSIZE];
+
+typedef struct {
+       unsigned int fhandle3_len;
+       char *fhandle3_val;
+} fhandle3;
+
+enum mountstat3 {
+       MNT_OK = 0,
+       MNT3ERR_PERM = 1,
+       MNT3ERR_NOENT = 2,
+       MNT3ERR_IO = 5,
+       MNT3ERR_ACCES = 13,
+       MNT3ERR_NOTDIR = 20,
+       MNT3ERR_INVAL = 22,
+       MNT3ERR_NAMETOOLONG = 63,
+       MNT3ERR_NOTSUPP = 10004,
+       MNT3ERR_SERVERFAULT = 10006,
+};
+typedef enum mountstat3 mountstat3;
+
+struct fhstatus {
+       unsigned int fhs_status;
+       union {
+               fhandle fhs_fhandle;
+       } fhstatus_u;
 };
+typedef struct fhstatus fhstatus;
 
+struct mountres3_ok {
+       fhandle3 fhandle;
+       struct {
+               unsigned int auth_flavours_len;
+               char *auth_flavours_val;
+       } auth_flavours;
+};
+typedef struct mountres3_ok mountres3_ok;
 
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-#include <fcntl.h>
-#include <sys/ioctl.h>
-static int use_loop = FALSE;
-#endif
+struct mountres3 {
+       mountstat3 fhs_status;
+       union {
+               mountres3_ok mountinfo;
+       } mountres3_u;
+};
+typedef struct mountres3 mountres3;
+
+typedef char *dirpath;
 
-extern int mount(__const char *__special_file, __const char *__dir,
-                                __const char *__fstype, unsigned long int __rwflag,
-                                __const void *__data);
-extern int umount(__const char *__special_file);
-extern int umount2(__const char *__special_file, int __flags);
+typedef char *name;
 
-extern int sysfs(int option, unsigned int fs_index, char *buf);
+typedef struct mountbody *mountlist;
 
-struct mount_options {
-       const char *name;
-       unsigned long and;
-       unsigned long or;
+struct mountbody {
+       name ml_hostname;
+       dirpath ml_directory;
+       mountlist ml_next;
 };
+typedef struct mountbody mountbody;
+
+typedef struct groupnode *groups;
 
-static const struct mount_options mount_options[] = {
-       {"async", ~MS_SYNCHRONOUS, 0},
-       {"atime", ~0, ~MS_NOATIME},
-       {"defaults", ~0, 0},
-       {"noauto", ~0, 0},
-       {"dev", ~MS_NODEV, 0},
-       {"diratime", ~0, ~MS_NODIRATIME},
-       {"exec", ~MS_NOEXEC, 0},
-       {"noatime", ~0, MS_NOATIME},
-       {"nodev", ~0, MS_NODEV},
-       {"nodiratime", ~0, MS_NODIRATIME},
-       {"noexec", ~0, MS_NOEXEC},
-       {"nosuid", ~0, MS_NOSUID},
-       {"remount", ~0, MS_REMOUNT},
-       {"ro", ~0, MS_RDONLY},
-       {"rw", ~MS_RDONLY, 0},
-       {"suid", ~MS_NOSUID, 0},
-       {"sync", ~0, MS_SYNCHRONOUS},
-       {"bind", ~0, MS_BIND},
-       {0, 0, 0}
+struct groupnode {
+       name gr_name;
+       groups gr_next;
 };
+typedef struct groupnode groupnode;
 
-static int
-do_mount(char *specialfile, char *dir, char *filesystemtype, long flags,
-                void *string_flags, int useMtab, int fakeIt, char *mtab_opts,
-                int mount_all)
-{
-       int status = 0;
+typedef struct exportnode *exports;
+
+struct exportnode {
+       dirpath ex_dir;
+       groups ex_groups;
+       exports ex_next;
+};
+typedef struct exportnode exportnode;
+
+struct ppathcnf {
+       int pc_link_max;
+       short pc_max_canon;
+       short pc_max_input;
+       short pc_name_max;
+       short pc_path_max;
+       short pc_pipe_buf;
+       u_char pc_vdisable;
+       char pc_xxx;
+       short pc_mask[2];
+};
+typedef struct ppathcnf ppathcnf;
+
+#define MOUNTPROG 100005
+#define MOUNTVERS 1
+
+#define MOUNTPROC_NULL 0
+#define MOUNTPROC_MNT 1
+#define MOUNTPROC_DUMP 2
+#define MOUNTPROC_UMNT 3
+#define MOUNTPROC_UMNTALL 4
+#define MOUNTPROC_EXPORT 5
+#define MOUNTPROC_EXPORTALL 6
+
+#define MOUNTVERS_POSIX 2
+
+#define MOUNTPROC_PATHCONF 7
 
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-       char *lofile = NULL;
+#define MOUNT_V3 3
+
+#define MOUNTPROC3_NULL 0
+#define MOUNTPROC3_MNT 1
+#define MOUNTPROC3_DUMP 2
+#define MOUNTPROC3_UMNT 3
+#define MOUNTPROC3_UMNTALL 4
+#define MOUNTPROC3_EXPORT 5
+
+enum {
+#ifndef NFS_FHSIZE
+       NFS_FHSIZE = 32,
 #endif
+#ifndef NFS_PORT
+       NFS_PORT = 2049
+#endif
+};
 
-       if (!fakeIt) {
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-               if (use_loop == TRUE) {
-                       int loro = flags & MS_RDONLY;
+/*
+ * We want to be able to compile mount on old kernels in such a way
+ * that the binary will work well on more recent kernels.
+ * Thus, if necessary we teach nfsmount.c the structure of new fields
+ * that will come later.
+ *
+ * Moreover, the new kernel includes conflict with glibc includes
+ * so it is easiest to ignore the kernel altogether (at compile time).
+ */
 
-                       lofile = specialfile;
+struct nfs2_fh {
+       char                    data[32];
+};
+struct nfs3_fh {
+       unsigned short          size;
+       unsigned char           data[64];
+};
 
-                       specialfile = find_unused_loop_device();
-                       if (specialfile == NULL) {
-                               bb_error_msg_and_die("Could not find a spare loop device");
-                       }
-                       if (set_loop(specialfile, lofile, 0, &loro)) {
-                               bb_error_msg_and_die("Could not setup loop device");
-                       }
-                       if (!(flags & MS_RDONLY) && loro) {     /* loop is ro, but wanted rw */
-                               bb_error_msg("WARNING: loop device is read-only");
-                               flags |= MS_RDONLY;
-                       }
-               }
+struct nfs_mount_data {
+       int             version;                /* 1 */
+       int             fd;                     /* 1 */
+       struct nfs2_fh  old_root;               /* 1 */
+       int             flags;                  /* 1 */
+       int             rsize;                  /* 1 */
+       int             wsize;                  /* 1 */
+       int             timeo;                  /* 1 */
+       int             retrans;                /* 1 */
+       int             acregmin;               /* 1 */
+       int             acregmax;               /* 1 */
+       int             acdirmin;               /* 1 */
+       int             acdirmax;               /* 1 */
+       struct sockaddr_in addr;                /* 1 */
+       char            hostname[256];          /* 1 */
+       int             namlen;                 /* 2 */
+       unsigned int    bsize;                  /* 3 */
+       struct nfs3_fh  root;                   /* 4 */
+};
+
+/* bits in the flags field */
+enum {
+       NFS_MOUNT_SOFT = 0x0001,        /* 1 */
+       NFS_MOUNT_INTR = 0x0002,        /* 1 */
+       NFS_MOUNT_SECURE = 0x0004,      /* 1 */
+       NFS_MOUNT_POSIX = 0x0008,       /* 1 */
+       NFS_MOUNT_NOCTO = 0x0010,       /* 1 */
+       NFS_MOUNT_NOAC = 0x0020,        /* 1 */
+       NFS_MOUNT_TCP = 0x0040,         /* 2 */
+       NFS_MOUNT_VER3 = 0x0080,        /* 3 */
+       NFS_MOUNT_KERBEROS = 0x0100,    /* 3 */
+       NFS_MOUNT_NONLM = 0x0200        /* 3 */
+};
+
+
+/*
+ * We need to translate between nfs status return values and
+ * the local errno values which may not be the same.
+ *
+ * Andreas Schwab <schwab@LS5.informatik.uni-dortmund.de>: change errno:
+ * "after #include <errno.h> the symbol errno is reserved for any use,
+ *  it cannot even be used as a struct tag or field name".
+ */
+
+#ifndef EDQUOT
+#define EDQUOT ENOSPC
 #endif
-               status = mount(specialfile, dir, filesystemtype, flags, string_flags);
-               if (status < 0 && errno == EROFS) {
-                       bb_error_msg("%s is write-protected, mounting read-only",
-                                         specialfile);
-                       status = mount(specialfile, dir, filesystemtype, flags |=
-                                                  MS_RDONLY, string_flags);
-               }
-               /* Don't whine about already mounted filesystems when mounting all. */
-               if (status < 0 && errno == EBUSY && mount_all) {
-                       return TRUE;
-               }
+
+// Convert each NFSERR_BLAH into EBLAH
+
+static const struct {
+       int stat;
+       int errnum;
+} nfs_errtbl[] = {
+       {0,0}, {1,EPERM}, {2,ENOENT}, {5,EIO}, {6,ENXIO}, {13,EACCES}, {17,EEXIST},
+       {19,ENODEV}, {20,ENOTDIR}, {21,EISDIR}, {22,EINVAL}, {27,EFBIG},
+       {28,ENOSPC}, {30,EROFS}, {63,ENAMETOOLONG}, {66,ENOTEMPTY}, {69,EDQUOT},
+       {70,ESTALE}, {71,EREMOTE}, {-1,EIO}
+};
+
+static char *nfs_strerror(int status)
+{
+       int i;
+       static char buf[sizeof("unknown nfs status return value: ") + sizeof(int)*3];
+
+       for (i = 0; nfs_errtbl[i].stat != -1; i++) {
+               if (nfs_errtbl[i].stat == status)
+                       return strerror(nfs_errtbl[i].errnum);
+       }
+       sprintf(buf, "unknown nfs status return value: %d", status);
+       return buf;
+}
+
+static bool_t xdr_fhandle(XDR *xdrs, fhandle objp)
+{
+       if (!xdr_opaque(xdrs, objp, FHSIZE))
+                return FALSE;
+       return TRUE;
+}
+
+static bool_t xdr_fhstatus(XDR *xdrs, fhstatus *objp)
+{
+       if (!xdr_u_int(xdrs, &objp->fhs_status))
+                return FALSE;
+       switch (objp->fhs_status) {
+       case 0:
+               if (!xdr_fhandle(xdrs, objp->fhstatus_u.fhs_fhandle))
+                        return FALSE;
+               break;
+       default:
+               break;
        }
+       return TRUE;
+}
 
+static bool_t xdr_dirpath(XDR *xdrs, dirpath *objp)
+{
+       if (!xdr_string(xdrs, objp, MNTPATHLEN))
+                return FALSE;
+       return TRUE;
+}
 
-       /* If the mount was sucessful, do anything needed, then return TRUE */
-       if (status == 0 || fakeIt == TRUE) {
+static bool_t xdr_fhandle3(XDR *xdrs, fhandle3 *objp)
+{
+       if (!xdr_bytes(xdrs, (char **)&objp->fhandle3_val, (unsigned int *) &objp->fhandle3_len, FHSIZE3))
+                return FALSE;
+       return TRUE;
+}
 
-#if defined CONFIG_FEATURE_MTAB_SUPPORT
-               if (useMtab) {
-                       erase_mtab(specialfile);        /* Clean any stale entries */
-                       write_mtab(specialfile, dir, filesystemtype, flags, mtab_opts);
-               }
-#endif
-               return (TRUE);
+static bool_t xdr_mountres3_ok(XDR *xdrs, mountres3_ok *objp)
+{
+       if (!xdr_fhandle3(xdrs, &objp->fhandle))
+               return FALSE;
+       if (!xdr_array(xdrs, &(objp->auth_flavours.auth_flavours_val), &(objp->auth_flavours.auth_flavours_len), ~0,
+                               sizeof (int), (xdrproc_t) xdr_int))
+               return FALSE;
+       return TRUE;
+}
+
+static bool_t xdr_mountstat3(XDR *xdrs, mountstat3 *objp)
+{
+       if (!xdr_enum(xdrs, (enum_t *) objp))
+                return FALSE;
+       return TRUE;
+}
+
+static bool_t xdr_mountres3(XDR *xdrs, mountres3 *objp)
+{
+       if (!xdr_mountstat3(xdrs, &objp->fhs_status))
+               return FALSE;
+       switch (objp->fhs_status) {
+       case MNT_OK:
+               if (!xdr_mountres3_ok(xdrs, &objp->mountres3_u.mountinfo))
+                        return FALSE;
+               break;
+       default:
+               break;
        }
+       return TRUE;
+}
 
-       /* Bummer.  mount failed.  Clean up */
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-       if (lofile != NULL) {
-               del_loop(specialfile);
+#define MAX_NFSPROT ((nfs_mount_version >= 4) ? 3 : 2)
+
+/*
+ * nfs_mount_version according to the sources seen at compile time.
+ */
+static int nfs_mount_version;
+static int kernel_version;
+
+/*
+ * Unfortunately, the kernel prints annoying console messages
+ * in case of an unexpected nfs mount version (instead of
+ * just returning some error).  Therefore we'll have to try
+ * and figure out what version the kernel expects.
+ *
+ * Variables:
+ *     KERNEL_NFS_MOUNT_VERSION: kernel sources at compile time
+ *     NFS_MOUNT_VERSION: these nfsmount sources at compile time
+ *     nfs_mount_version: version this source and running kernel can handle
+ */
+static void
+find_kernel_nfs_mount_version(void)
+{
+       if (kernel_version)
+               return;
+
+       nfs_mount_version = 4; /* default */
+
+       kernel_version = get_linux_version_code();
+       if (kernel_version) {
+               if (kernel_version < KERNEL_VERSION(2,1,32))
+                       nfs_mount_version = 1;
+               else if (kernel_version < KERNEL_VERSION(2,2,18) ||
+                               (kernel_version >= KERNEL_VERSION(2,3,0) &&
+                                kernel_version < KERNEL_VERSION(2,3,99)))
+                       nfs_mount_version = 3;
+               /* else v4 since 2.3.99pre4 */
        }
-#endif
+}
 
-       if (errno == EPERM) {
-               bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+static struct pmap *
+get_mountport(struct sockaddr_in *server_addr,
+       long unsigned prog,
+       long unsigned version,
+       long unsigned proto,
+       long unsigned port)
+{
+       struct pmaplist *pmap;
+       static struct pmap p = {0, 0, 0, 0};
+
+       server_addr->sin_port = PMAPPORT;
+       pmap = pmap_getmaps(server_addr);
+
+       if (version > MAX_NFSPROT)
+               version = MAX_NFSPROT;
+       if (!prog)
+               prog = MOUNTPROG;
+       p.pm_prog = prog;
+       p.pm_vers = version;
+       p.pm_prot = proto;
+       p.pm_port = port;
+
+       while (pmap) {
+               if (pmap->pml_map.pm_prog != prog)
+                       goto next;
+               if (!version && p.pm_vers > pmap->pml_map.pm_vers)
+                       goto next;
+               if (version > 2 && pmap->pml_map.pm_vers != version)
+                       goto next;
+               if (version && version <= 2 && pmap->pml_map.pm_vers > 2)
+                       goto next;
+               if (pmap->pml_map.pm_vers > MAX_NFSPROT ||
+                   (proto && p.pm_prot && pmap->pml_map.pm_prot != proto) ||
+                   (port && pmap->pml_map.pm_port != port))
+                       goto next;
+               memcpy(&p, &pmap->pml_map, sizeof(p));
+next:
+               pmap = pmap->pml_next;
        }
+       if (!p.pm_vers)
+               p.pm_vers = MOUNTVERS;
+       if (!p.pm_port)
+               p.pm_port = MOUNTPORT;
+       if (!p.pm_prot)
+               p.pm_prot = IPPROTO_TCP;
+       return &p;
+}
 
-       return (FALSE);
+static int daemonize(void)
+{
+       int fd;
+       int pid = fork();
+       if (pid < 0) /* error */
+               return -errno;
+       if (pid > 0) /* parent */
+               return 0;
+       /* child */
+       fd = xopen(bb_dev_null, O_RDWR);
+       dup2(fd, 0);
+       dup2(fd, 1);
+       dup2(fd, 2);
+       if (fd > 2) close(fd);
+       setsid();
+       openlog(applet_name, LOG_PID, LOG_DAEMON);
+       logmode = LOGMODE_SYSLOG;
+       return 1;
 }
 
+// TODO
+static inline int we_saw_this_host_before(const char *hostname)
+{
+       return 0;
+}
 
-static void paste_str(char **s1, const char *s2)
+/* RPC strerror analogs are terminally idiotic:
+ * *mandatory* prefix and \n at end.
+ * This hopefully helps. Usage:
+ * error_msg_rpc(clnt_*error*(" ")) */
+static void error_msg_rpc(const char *msg)
 {
-       *s1 = xrealloc(*s1, strlen(*s1) + strlen(s2) + 1);
-       strcat(*s1, s2);
+       int len;
+       while (msg[0] == ' ' || msg[0] == ':') msg++;
+       len = strlen(msg);
+       while (len && msg[len-1] == '\n') len--;
+       bb_error_msg("%.*s", len, msg);
 }
 
-/* Seperate standard mount options from the nonstandard string options */
-static void parse_mount_options(char *options, int *flags, char **strflags)
+// NB: mp->xxx fields may be trashed on exit
+static int nfsmount(struct mntent *mp, int vfsflags, char *filteropts)
 {
-       while (options) {
-               int gotone = FALSE;
-               char *comma = strchr(options, ',');
-               const struct mount_options *f = mount_options;
+       CLIENT *mclient;
+       char *hostname;
+       char *pathname;
+       char *mounthost;
+       struct nfs_mount_data data;
+       char *opt;
+       struct hostent *hp;
+       struct sockaddr_in server_addr;
+       struct sockaddr_in mount_server_addr;
+       int msock, fsock;
+       union {
+               struct fhstatus nfsv2;
+               struct mountres3 nfsv3;
+       } status;
+       int daemonized;
+       char *s;
+       int port;
+       int mountport;
+       int proto;
+       int bg;
+       int soft;
+       int intr;
+       int posix;
+       int nocto;
+       int noac;
+       int nolock;
+       int retry;
+       int tcp;
+       int mountprog;
+       int mountvers;
+       int nfsprog;
+       int nfsvers;
+       int retval;
 
-               if (comma) {
-                       *comma = '\0';
+       find_kernel_nfs_mount_version();
+
+       daemonized = 0;
+       mounthost = NULL;
+       retval = ETIMEDOUT;
+       msock = fsock = -1;
+       mclient = NULL;
+
+       /* NB: hostname, mounthost, filteropts must be free()d prior to return */
+
+       filteropts = xstrdup(filteropts); /* going to trash it later... */
+
+       hostname = xstrdup(mp->mnt_fsname);
+       /* mount_main() guarantees that ':' is there */
+       s = strchr(hostname, ':');
+       pathname = s + 1;
+       *s = '\0';
+       /* Ignore all but first hostname in replicated mounts
+          until they can be fully supported. (mack@sgi.com) */
+       s = strchr(hostname, ',');
+       if (s) {
+               *s = '\0';
+               bb_error_msg("warning: multiple hostnames not supported");
+       }
+
+       server_addr.sin_family = AF_INET;
+       if (!inet_aton(hostname, &server_addr.sin_addr)) {
+               hp = gethostbyname(hostname);
+               if (hp == NULL) {
+                       bb_herror_msg("%s", hostname);
+                       goto fail;
                }
+               if (hp->h_length > sizeof(struct in_addr)) {
+                       bb_error_msg("got bad hp->h_length");
+                       hp->h_length = sizeof(struct in_addr);
+               }
+               memcpy(&server_addr.sin_addr,
+                               hp->h_addr, hp->h_length);
+       }
 
-               while (f->name != 0) {
-                       if (strcasecmp(f->name, options) == 0) {
+       memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));
 
-                               *flags &= f->and;
-                               *flags |= f->or;
-                               gotone = TRUE;
-                               break;
+       /* add IP address to mtab options for use when unmounting */
+
+       if (!mp->mnt_opts) { /* TODO: actually mp->mnt_opts is never NULL */
+               mp->mnt_opts = xasprintf("addr=%s", inet_ntoa(server_addr.sin_addr));
+       } else {
+               char *tmp = xasprintf("%s%saddr=%s", mp->mnt_opts,
+                                       mp->mnt_opts[0] ? "," : "",
+                                       inet_ntoa(server_addr.sin_addr));
+               free(mp->mnt_opts);
+               mp->mnt_opts = tmp;
+       }
+
+       /* Set default options.
+        * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
+        * let the kernel decide.
+        * timeo is filled in after we know whether it'll be TCP or UDP. */
+       memset(&data, 0, sizeof(data));
+       data.retrans    = 3;
+       data.acregmin   = 3;
+       data.acregmax   = 60;
+       data.acdirmin   = 30;
+       data.acdirmax   = 60;
+       data.namlen     = NAME_MAX;
+
+       bg = 0;
+       soft = 0;
+       intr = 0;
+       posix = 0;
+       nocto = 0;
+       nolock = 0;
+       noac = 0;
+       retry = 10000;          /* 10000 minutes ~ 1 week */
+       tcp = 0;
+
+       mountprog = MOUNTPROG;
+       mountvers = 0;
+       port = 0;
+       mountport = 0;
+       nfsprog = 100003;
+       nfsvers = 0;
+
+       /* parse options */
+
+       for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
+               char *opteq = strchr(opt, '=');
+               if (opteq) {
+                       int val = xatoi_u(opteq + 1);
+                       *opteq = '\0';
+                       if (!strcmp(opt, "rsize"))
+                               data.rsize = val;
+                       else if (!strcmp(opt, "wsize"))
+                               data.wsize = val;
+                       else if (!strcmp(opt, "timeo"))
+                               data.timeo = val;
+                       else if (!strcmp(opt, "retrans"))
+                               data.retrans = val;
+                       else if (!strcmp(opt, "acregmin"))
+                               data.acregmin = val;
+                       else if (!strcmp(opt, "acregmax"))
+                               data.acregmax = val;
+                       else if (!strcmp(opt, "acdirmin"))
+                               data.acdirmin = val;
+                       else if (!strcmp(opt, "acdirmax"))
+                               data.acdirmax = val;
+                       else if (!strcmp(opt, "actimeo")) {
+                               data.acregmin = val;
+                               data.acregmax = val;
+                               data.acdirmin = val;
+                               data.acdirmax = val;
+                       }
+                       else if (!strcmp(opt, "retry"))
+                               retry = val;
+                       else if (!strcmp(opt, "port"))
+                               port = val;
+                       else if (!strcmp(opt, "mountport"))
+                               mountport = val;
+                       else if (!strcmp(opt, "mounthost"))
+                               mounthost = xstrndup(opteq+1,
+                                                 strcspn(opteq+1," \t\n\r,"));
+                       else if (!strcmp(opt, "mountprog"))
+                               mountprog = val;
+                       else if (!strcmp(opt, "mountvers"))
+                               mountvers = val;
+                       else if (!strcmp(opt, "nfsprog"))
+                               nfsprog = val;
+                       else if (!strcmp(opt, "nfsvers") ||
+                                !strcmp(opt, "vers"))
+                               nfsvers = val;
+                       else if (!strcmp(opt, "proto")) {
+                               if (!strncmp(opteq+1, "tcp", 3))
+                                       tcp = 1;
+                               else if (!strncmp(opteq+1, "udp", 3))
+                                       tcp = 0;
+                               else
+                                       bb_error_msg("warning: unrecognized proto= option");
+                       } else if (!strcmp(opt, "namlen")) {
+                               if (nfs_mount_version >= 2)
+                                       data.namlen = val;
+                               else
+                                       bb_error_msg("warning: option namlen is not supported\n");
+                       } else if (!strcmp(opt, "addr"))
+                               /* ignore */;
+                       else {
+                               bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
+                               goto fail;
                        }
-                       f++;
-               }
-#if defined CONFIG_FEATURE_MOUNT_LOOP
-               if (!strcasecmp("loop", options)) {     /* loop device support */
-                       use_loop = TRUE;
-                       gotone = TRUE;
                }
-#endif
-               if (!gotone) {
-                       if (**strflags) {
-                               /* have previous parsed options */
-                               paste_str(strflags, ",");
+               else {
+                       int val = 1;
+                       if (!strncmp(opt, "no", 2)) {
+                               val = 0;
+                               opt += 2;
+                       }
+                       if (!strcmp(opt, "bg"))
+                               bg = val;
+                       else if (!strcmp(opt, "fg"))
+                               bg = !val;
+                       else if (!strcmp(opt, "soft"))
+                               soft = val;
+                       else if (!strcmp(opt, "hard"))
+                               soft = !val;
+                       else if (!strcmp(opt, "intr"))
+                               intr = val;
+                       else if (!strcmp(opt, "posix"))
+                               posix = val;
+                       else if (!strcmp(opt, "cto"))
+                               nocto = !val;
+                       else if (!strcmp(opt, "ac"))
+                               noac = !val;
+                       else if (!strcmp(opt, "tcp"))
+                               tcp = val;
+                       else if (!strcmp(opt, "udp"))
+                               tcp = !val;
+                       else if (!strcmp(opt, "lock")) {
+                               if (nfs_mount_version >= 3)
+                                       nolock = !val;
+                               else
+                                       bb_error_msg("warning: option nolock is not supported");
+                       } else {
+                               bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
+                               goto fail;
                        }
-                       paste_str(strflags, options);
                }
-               if (comma) {
-                       *comma = ',';
-                       options = ++comma;
+       }
+       proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;
+
+       data.flags = (soft ? NFS_MOUNT_SOFT : 0)
+               | (intr ? NFS_MOUNT_INTR : 0)
+               | (posix ? NFS_MOUNT_POSIX : 0)
+               | (nocto ? NFS_MOUNT_NOCTO : 0)
+               | (noac ? NFS_MOUNT_NOAC : 0);
+       if (nfs_mount_version >= 2)
+               data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
+       if (nfs_mount_version >= 3)
+               data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
+       if (nfsvers > MAX_NFSPROT || mountvers > MAX_NFSPROT) {
+               bb_error_msg("NFSv%d not supported", nfsvers);
+               goto fail;
+       }
+       if (nfsvers && !mountvers)
+               mountvers = (nfsvers < 3) ? 1 : nfsvers;
+       if (nfsvers && nfsvers < mountvers) {
+               mountvers = nfsvers;
+       }
+
+       /* Adjust options if none specified */
+       if (!data.timeo)
+               data.timeo = tcp ? 70 : 7;
+
+       data.version = nfs_mount_version;
+
+       if (vfsflags & MS_REMOUNT)
+               goto do_mount;
+
+       /*
+        * If the previous mount operation on the same host was
+        * backgrounded, and the "bg" for this mount is also set,
+        * give up immediately, to avoid the initial timeout.
+        */
+       if (bg && we_saw_this_host_before(hostname)) {
+               daemonized = daemonize(); /* parent or error */
+               if (daemonized <= 0) { /* parent or error */
+                       retval = -daemonized;
+                       goto ret;
+               }
+       }
+
+       /* create mount daemon client */
+       /* See if the nfs host = mount host. */
+       if (mounthost) {
+               if (mounthost[0] >= '0' && mounthost[0] <= '9') {
+                       mount_server_addr.sin_family = AF_INET;
+                       mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
                } else {
-                       break;
+                       hp = gethostbyname(mounthost);
+                       if (hp == NULL) {
+                               bb_herror_msg("%s", mounthost);
+                               goto fail;
+                       } else {
+                               if (hp->h_length > sizeof(struct in_addr)) {
+                                       bb_error_msg("got bad hp->h_length?");
+                                       hp->h_length = sizeof(struct in_addr);
+                               }
+                               mount_server_addr.sin_family = AF_INET;
+                               memcpy(&mount_server_addr.sin_addr,
+                                               hp->h_addr, hp->h_length);
+                       }
                }
        }
-}
 
-static int mount_one(char *blockDevice, char *directory, char *filesystemType,
-                                        unsigned long flags, char *string_flags, int useMtab,
-                                        int fakeIt, char *mtab_opts, int whineOnErrors,
-                                        int mount_all)
-{
-       int status = 0;
-       if (strcmp(filesystemType, "auto") == 0) {
-               char buf[255];
-               FILE *f;
-               int read_proc = 0;
-
-               f = fopen("/etc/filesystems", "r");
-
-               if (f) {
-                       while (fgets(buf, sizeof(buf), f)) {
-                               if (*buf == '*') {
-                                       read_proc = 1;
-                               } else if (*buf == '#') {
-                                       continue;
-                               } else {
-                                       filesystemType = buf;
-
-                                       /* Add NULL termination to each line */
-                                       while (*filesystemType && !isspace(*filesystemType)) {
-                                               filesystemType++;
-                                       }
-                                       *filesystemType = '\0';
-
-                                       filesystemType = buf;
-
-                                       if (bb_strlen(filesystemType)) {
-                                               status = do_mount(blockDevice, directory, filesystemType,
-                                                                        flags | MS_MGC_VAL, string_flags,
-                                                                        useMtab, fakeIt, mtab_opts, mount_all);
-                                               if (status) {
-                                                       break;
-                                               }
-                                       }
+       /*
+        * The following loop implements the mount retries. When the mount
+        * times out, and the "bg" option is set, we background ourself
+        * and continue trying.
+        *
+        * The case where the mount point is not present and the "bg"
+        * option is set, is treated as a timeout. This is done to
+        * support nested mounts.
+        *
+        * The "retry" count specified by the user is the number of
+        * minutes to retry before giving up.
+        */
+       {
+               struct timeval total_timeout;
+               struct timeval retry_timeout;
+               struct pmap* pm_mnt;
+               time_t t;
+               time_t prevt;
+               time_t timeout;
 
-                               }
+               retry_timeout.tv_sec = 3;
+               retry_timeout.tv_usec = 0;
+               total_timeout.tv_sec = 20;
+               total_timeout.tv_usec = 0;
+               timeout = time(NULL) + 60 * retry;
+               prevt = 0;
+               t = 30;
+retry:
+               /* be careful not to use too many CPU cycles */
+               if (t - prevt < 30)
+                       sleep(30);
+
+               pm_mnt = get_mountport(&mount_server_addr,
+                               mountprog,
+                               mountvers,
+                               proto,
+                               mountport);
+               nfsvers = (pm_mnt->pm_vers < 2) ? 2 : pm_mnt->pm_vers;
+
+               /* contact the mount daemon via TCP */
+               mount_server_addr.sin_port = htons(pm_mnt->pm_port);
+               msock = RPC_ANYSOCK;
+
+               switch (pm_mnt->pm_prot) {
+               case IPPROTO_UDP:
+                       mclient = clntudp_create(&mount_server_addr,
+                                                pm_mnt->pm_prog,
+                                                pm_mnt->pm_vers,
+                                                retry_timeout,
+                                                &msock);
+                       if (mclient)
+                               break;
+                       mount_server_addr.sin_port = htons(pm_mnt->pm_port);
+                       msock = RPC_ANYSOCK;
+               case IPPROTO_TCP:
+                       mclient = clnttcp_create(&mount_server_addr,
+                                                pm_mnt->pm_prog,
+                                                pm_mnt->pm_vers,
+                                                &msock, 0, 0);
+                       break;
+               default:
+                       mclient = 0;
+               }
+               if (!mclient) {
+                       if (!daemonized && prevt == 0)
+                               error_msg_rpc(clnt_spcreateerror(" "));
+               } else {
+                       enum clnt_stat clnt_stat;
+                       /* try to mount hostname:pathname */
+                       mclient->cl_auth = authunix_create_default();
+
+                       /* make pointers in xdr_mountres3 NULL so
+                        * that xdr_array allocates memory for us
+                        */
+                       memset(&status, 0, sizeof(status));
+
+                       if (pm_mnt->pm_vers == 3)
+                               clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
+                                             (xdrproc_t) xdr_dirpath,
+                                             (caddr_t) &pathname,
+                                             (xdrproc_t) xdr_mountres3,
+                                             (caddr_t) &status,
+                                             total_timeout);
+                       else
+                               clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
+                                             (xdrproc_t) xdr_dirpath,
+                                             (caddr_t) &pathname,
+                                             (xdrproc_t) xdr_fhstatus,
+                                             (caddr_t) &status,
+                                             total_timeout);
+
+                       if (clnt_stat == RPC_SUCCESS)
+                               goto prepare_kernel_data; /* we're done */
+                       if (errno != ECONNREFUSED) {
+                               error_msg_rpc(clnt_sperror(mclient, " "));
+                               goto fail;      /* don't retry */
                        }
-                       fclose(f);
+                       /* Connection refused */
+                       if (!daemonized && prevt == 0) /* print just once */
+                               error_msg_rpc(clnt_sperror(mclient, " "));
+                       auth_destroy(mclient->cl_auth);
+                       clnt_destroy(mclient);
+                       mclient = 0;
+                       close(msock);
                }
 
-               if (read_proc && !status) {
-                       
-                       f = bb_xfopen("/proc/filesystems", "r");
-
-                       while (fgets(buf, sizeof(buf), f) != NULL) {
-                               filesystemType = buf;
-                               if (*filesystemType == '\t') {  /* Not a nodev filesystem */
-
-                                       /* Add NULL termination to each line */
-                                       while (*filesystemType && *filesystemType != '\n') {
-                                               filesystemType++;
-                                       }
-                                       *filesystemType = '\0';
-
-                                       filesystemType = buf;
-                                       filesystemType++;       /* hop past tab */
-
-                                       status = do_mount(blockDevice, directory, filesystemType,
-                                                                flags | MS_MGC_VAL, string_flags, useMtab,
-                                                                fakeIt, mtab_opts, mount_all);
-                                       if (status) {
-                                               break;
-                                       }
-                               }
+               /* Timeout. We are going to retry... maybe */
+
+               if (!bg)
+                       goto fail;
+               if (!daemonized) {
+                       daemonized = daemonize();
+                       if (daemonized <= 0) { /* parent or error */
+                               retval = -daemonized;
+                               goto ret;
                        }
-                       fclose(f);
                }
+               prevt = t;
+               t = time(NULL);
+               if (t >= timeout)
+                       /* TODO error message */
+                       goto fail;
+
+               goto retry;
+       }
+
+prepare_kernel_data:
+
+       if (nfsvers == 2) {
+               if (status.nfsv2.fhs_status != 0) {
+                       bb_error_msg("%s:%s failed, reason given by server: %s",
+                               hostname, pathname,
+                               nfs_strerror(status.nfsv2.fhs_status));
+                       goto fail;
+               }
+               memcpy(data.root.data,
+                               (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
+                               NFS_FHSIZE);
+               data.root.size = NFS_FHSIZE;
+               memcpy(data.old_root.data,
+                               (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
+                               NFS_FHSIZE);
        } else {
-               status =
-                       do_mount(blockDevice, directory, filesystemType,
-                                        flags | MS_MGC_VAL, string_flags, useMtab, fakeIt,
-                                        mtab_opts, mount_all);
+               fhandle3 *my_fhandle;
+               if (status.nfsv3.fhs_status != 0) {
+                       bb_error_msg("%s:%s failed, reason given by server: %s",
+                               hostname, pathname,
+                               nfs_strerror(status.nfsv3.fhs_status));
+                       goto fail;
+               }
+               my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
+               memset(data.old_root.data, 0, NFS_FHSIZE);
+               memset(&data.root, 0, sizeof(data.root));
+               data.root.size = my_fhandle->fhandle3_len;
+               memcpy(data.root.data,
+                               (char *) my_fhandle->fhandle3_val,
+                               my_fhandle->fhandle3_len);
+
+               data.flags |= NFS_MOUNT_VER3;
        }
 
-       if (!status) {
-               if (whineOnErrors) {
-                       bb_perror_msg("Mounting %s on %s failed", blockDevice, directory);
+       /* create nfs socket for kernel */
+
+       if (tcp) {
+               if (nfs_mount_version < 3) {
+                       bb_error_msg("NFS over TCP is not supported");
+                       goto fail;
                }
-               return (FALSE);
+               fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+       } else
+               fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+       if (fsock < 0) {
+               bb_perror_msg("nfs socket");
+               goto fail;
        }
-       return (TRUE);
-}
+       if (bindresvport(fsock, 0) < 0) {
+               bb_perror_msg("nfs bindresvport");
+               goto fail;
+       }
+       if (port == 0) {
+               server_addr.sin_port = PMAPPORT;
+               port = pmap_getport(&server_addr, nfsprog, nfsvers,
+                                       tcp ? IPPROTO_TCP : IPPROTO_UDP);
+               if (port == 0)
+                       port = NFS_PORT;
+       }
+       server_addr.sin_port = htons(port);
 
-static void show_mounts(char *onlytype)
-{
-       FILE *mountTable = setmntent(bb_path_mtab_file, "r");
+       /* prepare data structure for kernel */
 
-       if (mountTable) {
-               struct mntent *m;
+       data.fd = fsock;
+       memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
+       strncpy(data.hostname, hostname, sizeof(data.hostname));
 
-               while ((m = getmntent(mountTable)) != 0) {
-                       char *blockDevice = m->mnt_fsname;
+       /* clean up */
 
-                       if (strcmp(blockDevice, "rootfs") == 0) {
-                               continue;
-                       } else if (strcmp(blockDevice, "/dev/root") == 0) {
-                               blockDevice = find_real_root_device_name(blockDevice);
-                       }
-                       if (!onlytype || (strcmp(m->mnt_type, onlytype) == 0)) {
-                               printf("%s on %s type %s (%s)\n", blockDevice, m->mnt_dir,
-                                          m->mnt_type, m->mnt_opts);
-                       }
-#ifdef CONFIG_FEATURE_CLEAN_UP
-                       if (blockDevice != m->mnt_fsname) {
-                               free(blockDevice);
+       auth_destroy(mclient->cl_auth);
+       clnt_destroy(mclient);
+       close(msock);
+
+       if (bg) {
+               /* We must wait until mount directory is available */
+               struct stat statbuf;
+               int delay = 1;
+               while (stat(mp->mnt_dir, &statbuf) == -1) {
+                       if (!daemonized) {
+                               daemonized = daemonize();
+                               if (daemonized <= 0) { /* parent or error */
+                                       retval = -daemonized;
+                                       goto ret;
+                               }
                        }
-#endif
+                       sleep(delay);   /* 1, 2, 4, 8, 16, 30, ... */
+                       delay *= 2;
+                       if (delay > 30)
+                               delay = 30;
                }
-               endmntent(mountTable);
-       } else {
-               bb_perror_msg_and_die(bb_path_mtab_file);
        }
-       exit(EXIT_SUCCESS);
+
+do_mount: /* perform actual mount */
+
+       mp->mnt_type = "nfs";
+       retval = mount_it_now(mp, vfsflags, (char*)&data);
+       goto ret;
+
+fail:  /* abort */
+
+       if (msock != -1) {
+               if (mclient) {
+                       auth_destroy(mclient->cl_auth);
+                       clnt_destroy(mclient);
+               }
+               close(msock);
+       }
+       if (fsock != -1)
+               close(fsock);
+
+ret:
+       free(hostname);
+       free(mounthost);
+       free(filteropts);
+       return retval;
 }
 
-extern int mount_main(int argc, char **argv)
+#else /* !ENABLE_FEATURE_MOUNT_NFS */
+
+/* Never called. Call should be optimized out. */
+int nfsmount(struct mntent *mp, int vfsflags, char *filteropts);
+
+#endif /* !ENABLE_FEATURE_MOUNT_NFS */
+
+// Mount one directory.  Handles CIFS, NFS, loopback, autobind, and filesystem
+// type detection.  Returns 0 for success, nonzero for failure.
+// NB: mp->xxx fields may be trashed on exit
+static int singlemount(struct mntent *mp, int ignore_busy)
 {
-       struct stat statbuf;
-       char *string_flags = bb_xstrdup("");
-       char *extra_opts;
-       int flags = 0;
-       char *filesystemType = "auto";
-       int got_filesystemType = 0;
-       char *device = xmalloc(PATH_MAX);
-       char *directory = xmalloc(PATH_MAX);
-       struct mntent *m = NULL;
-       int all = FALSE;
-       int fakeIt = FALSE;
-       int useMtab = TRUE;
-       int rc = EXIT_FAILURE;
-       FILE *f = 0;
-       int opt;
-
-       /* Parse options */
-       while ((opt = getopt(argc, argv, "o:rt:wafnv")) > 0) {
-               switch (opt) {
-               case 'o':
-                       parse_mount_options(optarg, &flags, &string_flags);
-                       break;
-               case 'r':
-                       flags |= MS_RDONLY;
-                       break;
-               case 't':
-                       filesystemType = optarg;
-                       got_filesystemType = 1;
-                       break;
-               case 'w':
-                       flags &= ~MS_RDONLY;
-                       break;
-               case 'a':
-                       all = TRUE;
-                       break;
-               case 'f':
-                       fakeIt = TRUE;
-                       break;
-#ifdef CONFIG_FEATURE_MTAB_SUPPORT
-               case 'n':
-                       useMtab = FALSE;
-                       break;
-#endif
-               case 'v':
-                       break;          /* ignore -v */
-               }
+       int rc = -1, vfsflags;
+       char *loopFile = 0, *filteropts = 0;
+       llist_t *fl = 0;
+       struct stat st;
+
+       vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);
+
+       // Treat fstype "auto" as unspecified.
+
+       if (mp->mnt_type && !strcmp(mp->mnt_type,"auto")) mp->mnt_type = 0;
+
+       // Might this be an CIFS filesystem?
+
+       if (ENABLE_FEATURE_MOUNT_CIFS &&
+               (!mp->mnt_type || !strcmp(mp->mnt_type,"cifs")) &&
+               (mp->mnt_fsname[0]==mp->mnt_fsname[1] && (mp->mnt_fsname[0]=='/' || mp->mnt_fsname[0]=='\\')))
+       {
+               struct hostent *he;
+               char ip[32], *s;
+
+               rc = 1;
+               // Replace '/' with '\' and verify that unc points to "//server/share".
+
+               for (s = mp->mnt_fsname; *s; ++s)
+                       if (*s == '/') *s = '\\';
+
+               // get server IP
+
+               s = strrchr(mp->mnt_fsname, '\\');
+               if (s == mp->mnt_fsname+1) goto report_error;
+               *s = 0;
+               he = gethostbyname(mp->mnt_fsname+2);
+               *s = '\\';
+               if (!he) goto report_error;
+
+               // Insert ip=... option into string flags.  (NOTE: Add IPv6 support.)
+
+               sprintf(ip, "ip=%d.%d.%d.%d", he->h_addr[0], he->h_addr[1],
+                               he->h_addr[2], he->h_addr[3]);
+               parse_mount_options(ip, &filteropts);
+
+               // compose new unc '\\server-ip\share'
+
+               mp->mnt_fsname = xasprintf("\\\\%s%s", ip+3,
+                                       strchr(mp->mnt_fsname+2,'\\'));
+
+               // lock is required
+               vfsflags |= MS_MANDLOCK;
+
+               mp->mnt_type = "cifs";
+               rc = mount_it_now(mp, vfsflags, filteropts);
+               if (ENABLE_FEATURE_CLEAN_UP) free(mp->mnt_fsname);
+               goto report_error;
        }
 
-       if (!all && (optind == argc)) {
-               show_mounts(got_filesystemType ? filesystemType : NULL);
+       // Might this be an NFS filesystem?
+
+       if (ENABLE_FEATURE_MOUNT_NFS &&
+               (!mp->mnt_type || !strcmp(mp->mnt_type,"nfs")) &&
+               strchr(mp->mnt_fsname, ':') != NULL)
+       {
+               rc = nfsmount(mp, vfsflags, filteropts);
+               goto report_error;
        }
 
-       if (optind < argc) {
-               /* if device is a filename get its real path */
-               if (stat(argv[optind], &statbuf) == 0) {
-                       char *tmp = bb_simplify_path(argv[optind]);
+       // Look at the file.  (Not found isn't a failure for remount, or for
+       // a synthetic filesystem like proc or sysfs.)
 
-                       safe_strncpy(device, tmp, PATH_MAX);
-               } else {
-                       safe_strncpy(device, argv[optind], PATH_MAX);
+       if (!lstat(mp->mnt_fsname, &st) && !(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
+       {
+               // Do we need to allocate a loopback device for it?
+
+               if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
+                       loopFile = bb_simplify_path(mp->mnt_fsname);
+                       mp->mnt_fsname = 0;
+                       switch (set_loop(&(mp->mnt_fsname), loopFile, 0)) {
+                       case 0:
+                       case 1:
+                               break;
+                       default:
+                               bb_error_msg( errno == EPERM || errno == EACCES
+                                       ? bb_msg_perm_denied_are_you_root
+                                       : "cannot setup loop device");
+                               return errno;
+                       }
+
+               // Autodetect bind mounts
+
+               } else if (S_ISDIR(st.st_mode) && !mp->mnt_type)
+                       vfsflags |= MS_BIND;
+       }
+
+       /* If we know the fstype (or don't need to), jump straight
+        * to the actual mount. */
+
+       if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
+               rc = mount_it_now(mp, vfsflags, filteropts);
+
+       // Loop through filesystem types until mount succeeds or we run out
+
+       else {
+
+               /* Initialize list of block backed filesystems.  This has to be
+                * done here so that during "mount -a", mounts after /proc shows up
+                * can autodetect. */
+
+               if (!fslist) {
+                       fslist = get_block_backed_filesystems();
+                       if (ENABLE_FEATURE_CLEAN_UP && fslist)
+                               atexit(delete_block_backed_filesystems);
+               }
+
+               for (fl = fslist; fl; fl = fl->link) {
+                       mp->mnt_type = fl->data;
+                       rc = mount_it_now(mp, vfsflags, filteropts);
+                       if (!rc) break;
                }
        }
 
-       if (optind + 1 < argc)
-               directory = bb_simplify_path(argv[optind + 1]);
+       // If mount failed, clean up loop file (if any).
 
-       if (all || optind + 1 == argc) {
-               f = setmntent("/etc/fstab", "r");
+       if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) {
+               del_loop(mp->mnt_fsname);
+               if (ENABLE_FEATURE_CLEAN_UP) {
+                       free(loopFile);
+                       free(mp->mnt_fsname);
+               }
+       }
 
-               if (f == NULL)
-                       bb_perror_msg_and_die("\nCannot read /etc/fstab");
+report_error:
+       if (ENABLE_FEATURE_CLEAN_UP) free(filteropts);
 
-               while ((m = getmntent(f)) != NULL) {
-                       if (!all && (optind + 1 == argc)
-                               && ((strcmp(device, m->mnt_fsname) != 0)
-                                       && (strcmp(device, m->mnt_dir) != 0))) {
-                               continue;
-                       }
+       if (rc && errno == EBUSY && ignore_busy) rc = 0;
+       if (rc < 0)
+               /* perror here sometimes says "mounting ... on ... failed: Success" */
+               bb_error_msg("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
+
+       return rc;
+}
+
+// Parse options, if necessary parse fstab/mtab, and call singlemount for
+// each directory to be mounted.
+
+int mount_main(int argc, char **argv)
+{
+       enum { OPT_ALL = 0x10 };
+
+       char *cmdopts = xstrdup(""), *fstype=0, *storage_path=0;
+       char *opt_o;
+       const char *fstabname;
+       FILE *fstab;
+       int i, j, rc = 0;
+       unsigned opt;
+       struct mntent mtpair[2], *mtcur = mtpair;
+
+       /* parse long options, like --bind and --move.  Note that -o option
+        * and --option are synonymous.  Yes, this means --remount,rw works. */
+
+       for (i = j = 0; i < argc; i++) {
+               if (argv[i][0] == '-' && argv[i][1] == '-') {
+                       append_mount_options(&cmdopts,argv[i]+2);
+               } else argv[j++] = argv[i];
+       }
+       argv[j] = 0;
+       argc = j;
+
+       // Parse remaining options
+
+       opt = getopt32(argc, argv, "o:t:rwanfvs", &opt_o, &fstype);
+       if (opt & 0x1) append_mount_options(&cmdopts, opt_o); // -o
+       //if (opt & 0x2) // -t
+       if (opt & 0x4) append_mount_options(&cmdopts, "ro"); // -r
+       if (opt & 0x8) append_mount_options(&cmdopts, "rw"); // -w
+       //if (opt & 0x10) // -a
+       if (opt & 0x20) USE_FEATURE_MTAB_SUPPORT(useMtab = 0); // -n
+       if (opt & 0x40) USE_FEATURE_MTAB_SUPPORT(fakeIt = 1); // -f
+       //if (opt & 0x80) // -v: verbose (ignore)
+       //if (opt & 0x100) // -s: sloppy (ignore)
+       argv += optind;
+       argc -= optind;
+
+       // Three or more non-option arguments?  Die with a usage message.
 
-                       if (all && (    /* If we're mounting 'all' */
-                                                  (strstr(m->mnt_opts, "noauto")) ||   /* and the file system isn't noauto, */
-                                                  (strstr(m->mnt_type, "swap")))) /* and isn't swap, then mount it */
+       if (argc > 2) bb_show_usage();
+
+       // If we have no arguments, show currently mounted filesystems
+
+       if (!argc) {
+               if (!(opt & OPT_ALL)) {
+                       FILE *mountTable = setmntent(bb_path_mtab_file, "r");
+
+                       if (!mountTable) bb_error_msg_and_die("no %s",bb_path_mtab_file);
+
+                       while (getmntent_r(mountTable,mtpair,bb_common_bufsiz1,
+                                                               sizeof(bb_common_bufsiz1)))
                        {
-                               continue;
-                       }
+                               // Don't show rootfs.
+                               if (!strcmp(mtpair->mnt_fsname, "rootfs")) continue;
 
-                       if (all || flags == 0) {        /* Allow single mount to override fstab flags */
-                               flags = 0;
-                               string_flags[0] = 0;
-                               parse_mount_options(m->mnt_opts, &flags, &string_flags);
+                               if (!fstype || !strcmp(mtpair->mnt_type, fstype))
+                                       printf("%s on %s type %s (%s)\n", mtpair->mnt_fsname,
+                                                       mtpair->mnt_dir, mtpair->mnt_type,
+                                                       mtpair->mnt_opts);
                        }
+                       if (ENABLE_FEATURE_CLEAN_UP) endmntent(mountTable);
+                       return EXIT_SUCCESS;
+               }
+       } else storage_path = bb_simplify_path(argv[0]);
 
-                       strcpy(device, m->mnt_fsname);
-                       strcpy(directory, m->mnt_dir);
-                       filesystemType = bb_xstrdup(m->mnt_type);
-                 singlemount:
-                       extra_opts = string_flags;
-                       rc = EXIT_SUCCESS;
-#ifdef CONFIG_NFSMOUNT
-                       if (strchr(device, ':') != NULL) {
-                               filesystemType = "nfs";
-                               if (nfsmount
-                                       (device, directory, &flags, &extra_opts, &string_flags,
-                                        1)) {
-                                       bb_perror_msg("nfsmount failed");
-                                       rc = EXIT_FAILURE;
-                               }
-                       }
-#endif
-                       if (!mount_one
-                               (device, directory, filesystemType, flags, string_flags,
-                                useMtab, fakeIt, extra_opts, TRUE, all)) {
-                               rc = EXIT_FAILURE;
-                       }
-                       if (!all) {
-                               break;
+       // When we have two arguments, the second is the directory and we can
+       // skip looking at fstab entirely.  We can always abspath() the directory
+       // argument when we get it.
+
+       if (argc == 2) {
+               mtpair->mnt_fsname = argv[0];
+               mtpair->mnt_dir = argv[1];
+               mtpair->mnt_type = fstype;
+               mtpair->mnt_opts = cmdopts;
+               rc = singlemount(mtpair, 0);
+               goto clean_up;
+       }
+
+       i = parse_mount_options(cmdopts, 0);
+
+       // If we have a shared subtree flag, don't worry about fstab or mtab.
+
+       if (ENABLE_FEATURE_MOUNT_FLAGS &&
+                       (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE )))
+       {
+               rc = mount("", argv[0], "", i, "");
+               if (rc) bb_perror_msg_and_die("%s", argv[0]);
+               goto clean_up;
+       }
+
+       // Open either fstab or mtab
+
+       if (i & MS_REMOUNT)
+               fstabname = bb_path_mtab_file;
+       else fstabname = "/etc/fstab";
+       fstab = setmntent(fstabname,"r");
+       if (!fstab)
+               bb_perror_msg_and_die("cannot read %s", fstabname);
+
+       // Loop through entries until we find what we're looking for.
+
+       memset(mtpair, 0, sizeof(mtpair));
+       for (;;) {
+               struct mntent *mtnext = (mtcur==mtpair ? mtpair+1 : mtpair);
+
+               // Get next fstab entry
+
+               if (!getmntent_r(fstab, mtcur, bb_common_bufsiz1
+                                       + (mtcur==mtpair ? sizeof(bb_common_bufsiz1)/2 : 0),
+                               sizeof(bb_common_bufsiz1)/2))
+               {
+                       // Were we looking for something specific?
+
+                       if (argc) {
+
+                               // If we didn't find anything, complain.
+
+                               if (!mtnext->mnt_fsname)
+                                       bb_error_msg_and_die("can't find %s in %s",
+                                               argv[0], fstabname);
+
+                               // Mount the last thing we found.
+
+                               mtcur = mtnext;
+                               mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
+                               append_mount_options(&(mtcur->mnt_opts),cmdopts);
+                               rc = singlemount(mtcur, 0);
+                               free(mtcur->mnt_opts);
                        }
+                       goto clean_up;
                }
-               if (f) {
-                       endmntent(f);
-               }
-               if (!all && f && m == NULL) {
-                       fprintf(stderr, "Can't find %s in /etc/fstab\n", device);
+
+               /* If we're trying to mount something specific and this isn't it,
+                * skip it.  Note we must match both the exact text in fstab (ala
+                * "proc") or a full path from root */
+
+               if (argc) {
+
+                       // Is this what we're looking for?
+
+                       if (strcmp(argv[0],mtcur->mnt_fsname) &&
+                          strcmp(storage_path,mtcur->mnt_fsname) &&
+                          strcmp(argv[0],mtcur->mnt_dir) &&
+                          strcmp(storage_path,mtcur->mnt_dir)) continue;
+
+                       // Remember this entry.  Something later may have overmounted
+                       // it, and we want the _last_ match.
+
+                       mtcur = mtnext;
+
+               // If we're mounting all.
+
+               } else {
+
+                       // Do we need to match a filesystem type?
+                       if (fstype && strcmp(mtcur->mnt_type,fstype)) continue;
+
+                       // Skip noauto and swap anyway.
+
+                       if (parse_mount_options(mtcur->mnt_opts,0)
+                               & (MOUNT_NOAUTO | MOUNT_SWAP)) continue;
+
+                       // Mount this thing.
+
+                       if (singlemount(mtcur, 1)) {
+                               /* Count number of failed mounts */
+                               rc++;
+                       }
                }
-               return rc;
+       }
+       if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);
+
+clean_up:
+
+       if (ENABLE_FEATURE_CLEAN_UP) {
+               free(storage_path);
+               free(cmdopts);
        }
 
-       goto singlemount;
+       return rc;
 }