hush: rename o_quoted to has_quoted_part; small code shrink
[oweals/busybox.git] / util-linux / mount.c
index f665a08758e2377809a04ba726448bba79c777f2..5e85f998641c473ef5f4e66c42dc394b245adc80 100644 (file)
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  * Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+// 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 <mntent.h>
+#include <syslog.h>
+#include <sys/mount.h>
+// Grab more as needed from util-linux's mount/mount_constants.h
+#ifndef MS_DIRSYNC
+# define MS_DIRSYNC     (1 << 7) // Directory modifications are synchronous
+#endif
+#ifndef MS_UNION
+# define MS_UNION       (1 << 8)
+#endif
+#ifndef MS_BIND
+# define MS_BIND        (1 << 12)
+#endif
+#ifndef MS_MOVE
+# define MS_MOVE        (1 << 13)
+#endif
+#ifndef MS_RECURSIVE
+# define MS_RECURSIVE   (1 << 14)
+#endif
+#ifndef MS_SILENT
+# define MS_SILENT      (1 << 15)
+#endif
+// The shared subtree stuff, which went in around 2.6.15
+#ifndef MS_UNBINDABLE
+# define MS_UNBINDABLE  (1 << 17)
+#endif
+#ifndef MS_PRIVATE
+# define MS_PRIVATE     (1 << 18)
+#endif
+#ifndef MS_SLAVE
+# define MS_SLAVE       (1 << 19)
+#endif
+#ifndef MS_SHARED
+# define MS_SHARED      (1 << 20)
+#endif
+#ifndef MS_RELATIME
+# define MS_RELATIME    (1 << 21)
+#endif
 
-/* todo:
- * bb_getopt_ulflags();
- */
+#include "libbb.h"
+#if ENABLE_FEATURE_MOUNT_LABEL
+# include "volume_id.h"
+#else
+# define resolve_mount_spec(fsname) ((void)0)
+#endif
 
-/* Design notes: There is no spec for mount.  Remind me to write one.
+// Needed for nfs support only
+#include <sys/utsname.h>
+#undef TRUE
+#undef FALSE
+#if ENABLE_FEATURE_MOUNT_NFS
+/* 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 NFS support"
+# endif
+# include <rpc/rpc.h>
+# include <rpc/pmap_prot.h>
+# include <rpc/pmap_clnt.h>
+#endif
 
-   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.
-*/
+#if defined(__dietlibc__)
+// 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
+// dietlibc-0.30 does not have implementation of getmntent_r()
+static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
+               char* buffer UNUSED_PARAM, int bufsize UNUSED_PARAM)
+{
+       struct mntent* ment = getmntent(stream);
+       return memcpy(result, ment, sizeof(*ment));
+}
+#endif
 
-#include "busybox.h"
-#include <mntent.h>
 
-// These two aren't always defined in old headers
-#ifndef MS_BIND
-#define MS_BIND                4096
+// Not real flags, but we want to be able to check for this.
+enum {
+       MOUNT_USERS  = (1 << 28) * ENABLE_DESKTOP,
+       MOUNT_NOAUTO = (1 << 29),
+       MOUNT_SWAP   = (1 << 30),
+};
+
+
+#define OPTION_STR "o:t:rwanfvsiO:"
+enum {
+       OPT_o = (1 << 0),
+       OPT_t = (1 << 1),
+       OPT_r = (1 << 2),
+       OPT_w = (1 << 3),
+       OPT_a = (1 << 4),
+       OPT_n = (1 << 5),
+       OPT_f = (1 << 6),
+       OPT_v = (1 << 7),
+       OPT_s = (1 << 8),
+       OPT_i = (1 << 9),
+       OPT_O = (1 << 10),
+};
+
+#if ENABLE_FEATURE_MTAB_SUPPORT
+#define USE_MTAB (!(option_mask32 & OPT_n))
+#else
+#define USE_MTAB 0
 #endif
-#ifndef MS_MOVE
-#define MS_MOVE                8192
+
+#if ENABLE_FEATURE_MOUNT_FAKE
+#define FAKE_IT (option_mask32 & OPT_f)
+#else
+#define FAKE_IT 0
 #endif
-#ifndef MS_SILENT
-#define MS_SILENT      32768
+
+#if ENABLE_FEATURE_MOUNT_HELPERS
+#define HELPERS_ALLOWED (!(option_mask32 & OPT_i))
+#else
+#define HELPERS_ALLOWED 0
 #endif
 
-// 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 {
-       const char *name;
-       long flags;
-} static const mount_options[] = {
-       // NOP flags.
-
-       {"loop", 0},
-       {"defaults", 0},
-       {"quiet", 0},
-
-       // vfs flags
-
-       {"ro", MS_RDONLY},
-       {"rw", ~MS_RDONLY},
-       {"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
-
-       {"remount", MS_REMOUNT},
-       {"bind", MS_BIND},
-       {"move", MS_MOVE},
-       {"noauto",MOUNT_NOAUTO},
-       {"swap",MOUNT_SWAP}
+
+// TODO: more "user" flag compatibility.
+// "user" option (from mount manpage):
+// Only the user that mounted a filesystem can unmount it again.
+// If any user should be able to unmount, then use users instead of user
+// in the fstab line.  The owner option is similar to the user option,
+// with the restriction that the user must be the owner of the special file.
+// This may be useful e.g. for /dev/fd if a login script makes
+// the console user owner of this device.
+
+// Standard mount options (from -o options or --options),
+// with corresponding flags
+static const int32_t mount_options[] = {
+       // MS_FLAGS set a bit.  ~MS_FLAGS disable that bit.  0 flags are NOPs.
+
+       IF_FEATURE_MOUNT_LOOP(
+               /* "loop" */ 0,
+       )
+
+       IF_FEATURE_MOUNT_FSTAB(
+               /* "defaults" */ 0,
+               /* "quiet" 0 - do not filter out, vfat wants to see it */
+               /* "noauto" */ MOUNT_NOAUTO,
+               /* "sw"     */ MOUNT_SWAP,
+               /* "swap"   */ MOUNT_SWAP,
+               IF_DESKTOP(/* "user"  */ MOUNT_USERS,)
+               IF_DESKTOP(/* "users" */ MOUNT_USERS,)
+               /* "_netdev" */ 0,
+       )
+
+       IF_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,
+               /* "dirsync"     */ MS_DIRSYNC,
+               /* "async"       */ ~MS_SYNCHRONOUS,
+               /* "atime"       */ ~MS_NOATIME,
+               /* "noatime"     */ MS_NOATIME,
+               /* "diratime"    */ ~MS_NODIRATIME,
+               /* "nodiratime"  */ MS_NODIRATIME,
+               /* "mand"        */ MS_MANDLOCK,
+               /* "nomand"      */ ~MS_MANDLOCK,
+               /* "relatime"    */ MS_RELATIME,
+               /* "norelatime"  */ ~MS_RELATIME,
+               /* "loud"        */ ~MS_SILENT,
+
+               // action flags
+               /* "union"       */ MS_UNION,
+               /* "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
 };
 
-/* Append mount options to string */
-static void append_mount_options(char **oldopts, char *newopts)
+static const char mount_option_str[] =
+       IF_FEATURE_MOUNT_LOOP(
+               "loop\0"
+       )
+       IF_FEATURE_MOUNT_FSTAB(
+               "defaults\0"
+               // "quiet\0" - do not filter out, vfat wants to see it
+               "noauto\0"
+               "sw\0"
+               "swap\0"
+               IF_DESKTOP("user\0")
+               IF_DESKTOP("users\0")
+               "_netdev\0"
+       )
+       IF_FEATURE_MOUNT_FLAGS(
+               // vfs flags
+               "nosuid\0"
+               "suid\0"
+               "dev\0"
+               "nodev\0"
+               "exec\0"
+               "noexec\0"
+               "sync\0"
+               "dirsync\0"
+               "async\0"
+               "atime\0"
+               "noatime\0"
+               "diratime\0"
+               "nodiratime\0"
+               "mand\0"
+               "nomand\0"
+               "relatime\0"
+               "norelatime\0"
+               "loud\0"
+
+               // action flags
+               "union\0"
+               "bind\0"
+               "move\0"
+               "shared\0"
+               "slave\0"
+               "private\0"
+               "unbindable\0"
+               "rshared\0"
+               "rslave\0"
+               "rprivate\0"
+               "runbindable\0"
+       )
+
+       // Always understood.
+       "ro\0"        // vfs flag
+       "rw\0"        // vfs flag
+       "remount\0"   // action flag
+;
+
+
+struct globals {
+#if ENABLE_FEATURE_MOUNT_NFS
+       smalluint nfs_mount_version;
+#endif
+#if ENABLE_FEATURE_MOUNT_VERBOSE
+       unsigned verbose;
+#endif
+       llist_t *fslist;
+       char getmntent_buf[1];
+} FIX_ALIASING;
+enum { GETMNTENT_BUFSIZE = COMMON_BUFSIZE - offsetof(struct globals, getmntent_buf) };
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define nfs_mount_version (G.nfs_mount_version)
+#if ENABLE_FEATURE_MOUNT_VERBOSE
+#define verbose           (G.verbose          )
+#else
+#define verbose           0
+#endif
+#define fslist            (G.fslist           )
+#define getmntent_buf     (G.getmntent_buf    )
+
+
+#if ENABLE_FEATURE_MOUNT_VERBOSE
+static int verbose_mount(const char *source, const char *target,
+               const char *filesystemtype,
+               unsigned long mountflags, const void *data)
+{
+       int rc;
+
+       errno = 0;
+       rc = mount(source, target, filesystemtype, mountflags, data);
+       if (verbose >= 2)
+               bb_perror_msg("mount('%s','%s','%s',0x%08lx,'%s'):%d",
+                       source, target, filesystemtype,
+                       mountflags, (char*)data, rc);
+       return rc;
+}
+#else
+#define verbose_mount(...) mount(__VA_ARGS__)
+#endif
+
+// Append mount options to string
+static void append_mount_options(char **oldopts, const char *newopts)
 {
-       if(*oldopts && **oldopts) {
-               char *temp=xasprintf("%s,%s",*oldopts,newopts);
-               free(*oldopts);
-               *oldopts=temp;
+       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.
- * Return list of unrecognized options in *strflags if strflags!=NULL */
-static int parse_mount_options(char *options, char **unrecognized)
+// Use the mount_options list to parse options into flags.
+// Also return list of unrecognized options if unrecognized != NULL
+static long parse_mount_options(char *options, char **unrecognized)
 {
-       int flags = MS_SILENT;
+       long flags = MS_SILENT;
 
        // Loop through options
        for (;;) {
-               int i;
+               unsigned i;
                char *comma = strchr(options, ',');
+               const char *option_str = mount_option_str;
 
-               if (comma) *comma = 0;
+               if (comma) *comma = '\0';
 
+// FIXME: use hasmntopt()
                // Find this option in mount_options
-               for (i = 0; i < (sizeof(mount_options) / sizeof(*mount_options)); i++) {
-                       if (!strcasecmp(mount_options[i].name, options)) {
-                               long fl = mount_options[i].flags;
-                               if(fl < 0) flags &= fl;
+               for (i = 0; i < ARRAY_SIZE(mount_options); i++) {
+                       if (!strcasecmp(option_str, options)) {
+                               long fl = mount_options[i];
+                               if (fl < 0) flags &= fl;
                                else flags |= fl;
                                break;
                        }
+                       option_str += strlen(option_str) + 1;
                }
-               // If unrecognized not NULL, append unrecognized mount options */
-               if (unrecognized
-                               && i == (sizeof(mount_options) / sizeof(*mount_options)))
-               {
+               // If unrecognized not NULL, append unrecognized mount options
+               if (unrecognized && i == ARRAY_SIZE(mount_options)) {
                        // Add it to strflags, to pass on to kernel
                        i = *unrecognized ? strlen(*unrecognized) : 0;
-                       *unrecognized = xrealloc(*unrecognized, i+strlen(options)+2);
+                       *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;
+               if (!comma)
+                       break;
+               // Advance to next option
+               *comma = ',';
+               options = ++comma;
        }
 
        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;
+       static const char filesystems[2][sizeof("/proc/filesystems")] = {
+               "/etc/filesystems",
+               "/proc/filesystems",
+       };
+       char *fs, *buf;
+       llist_t *list = NULL;
        int i;
        FILE *f;
 
-       for(i = 0; filesystems[i]; i++) {
-               if(!(f = fopen(filesystems[i], "r"))) continue;
+       for (i = 0; i < 2; i++) {
+               f = fopen_for_read(filesystems[i]);
+               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 ((buf = xmalloc_fgetline(f)) != NULL) {
+                       if (strncmp(buf, "nodev", 5) == 0 && isspace(buf[5]))
+                               continue;
+                       fs = skip_whitespace(buf);
+                       if (*fs == '#' || *fs == '*' || !*fs)
+                               continue;
 
-                       while(isspace(*fs)) fs++;
-                       if(*fs=='#' || *fs=='*') continue;
-                       if(!*fs) continue;
-
-                       llist_add_to_end(&list,xstrdup(fs));
+                       llist_add_to_end(&list, xstrdup(fs));
+                       free(buf);
                }
                if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
        }
@@ -167,8 +409,6 @@ static llist_t *get_block_backed_filesystems(void)
        return list;
 }
 
-llist_t *fslist = 0;
-
 #if ENABLE_FEATURE_CLEAN_UP
 static void delete_block_backed_filesystems(void)
 {
@@ -178,31 +418,56 @@ static void delete_block_backed_filesystems(void)
 void delete_block_backed_filesystems(void);
 #endif
 
-#if ENABLE_FEATURE_MTAB_SUPPORT
-static int useMtab;
-static int fakeIt;
-#else
-#define useMtab 0
-#define fakeIt 0
-#endif
-
 // Perform actual mount of specific filesystem at specific location.
-
-static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
+// NB: mp->xxx fields may be trashed on exit
+static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
 {
-       int rc;
+       int rc = 0;
 
-       if (fakeIt) { return 0; }
+       if (FAKE_IT) {
+               if (verbose >= 2)
+                       bb_error_msg("would do mount('%s','%s','%s',0x%08lx,'%s')",
+                               mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
+                               vfsflags, filteropts);
+               goto mtab;
+       }
 
        // Mount, with fallback to read-only if necessary.
-
-       for(;;) {
-               rc = mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
+       for (;;) {
+               errno = 0;
+               rc = verbose_mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
                                vfsflags, filteropts);
-               if(!rc || (vfsflags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
+
+               // If mount failed, try
+               // helper program mount.<mnt_type>
+               if (HELPERS_ALLOWED && rc && mp->mnt_type) {
+                       char *args[8];
+                       int errno_save = errno;
+                       args[0] = xasprintf("mount.%s", mp->mnt_type);
+                       rc = 1;
+                       if (FAKE_IT)
+                               args[rc++] = (char *)"-f";
+                       if (ENABLE_FEATURE_MTAB_SUPPORT && !USE_MTAB)
+                               args[rc++] = (char *)"-n";
+                       args[rc++] = mp->mnt_fsname;
+                       args[rc++] = mp->mnt_dir;
+                       if (filteropts) {
+                               args[rc++] = (char *)"-o";
+                               args[rc++] = filteropts;
+                       }
+                       args[rc] = NULL;
+                       rc = spawn_and_wait(args);
+                       free(args[0]);
+                       if (!rc)
+                               break;
+                       errno = errno_save;
+               }
+
+               if (!rc || (vfsflags & MS_RDONLY) || (errno != EACCES && errno != EROFS))
                        break;
-               bb_error_msg("%s is write-protected, mounting read-only",
-                               mp->mnt_fsname);
+               if (!(vfsflags & MS_SILENT))
+                       bb_error_msg("%s is write-protected, mounting read-only",
+                                               mp->mnt_fsname);
                vfsflags |= MS_RDONLY;
        }
 
@@ -211,117 +476,1257 @@ static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
        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. */
-
-       if(ENABLE_FEATURE_MTAB_SUPPORT && useMtab && !rc) {
+       // 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 (USE_MTAB && !rc && !(vfsflags & MS_REMOUNT)) {
+               char *fsname;
                FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
+               const char *option_str = mount_option_str;
                int i;
 
-               if(!mountTable)
-                       bb_error_msg("No %s\n",bb_path_mtab_file);
+               if (!mountTable) {
+                       bb_error_msg("no %s", bb_path_mtab_file);
+                       goto ret;
+               }
 
                // Add vfs string flags
 
-               for(i=0; mount_options[i].flags != MS_REMOUNT; i++)
-                       if (mount_options[i].flags > 0)
-                               append_mount_options(&(mp->mnt_opts),
-// Shut up about the darn const.  It's not important.  I don't care.
-                                               (char *)mount_options[i].name);
+               for (i = 0; mount_options[i] != MS_REMOUNT; i++) {
+                       if (mount_options[i] > 0 && (mount_options[i] & vfsflags))
+                               append_mount_options(&(mp->mnt_opts), option_str);
+                       option_str += strlen(option_str) + 1;
+               }
 
                // Remove trailing / (if any) from directory we mounted on
 
-               i = strlen(mp->mnt_dir);
-               if(i>1 && mp->mnt_dir[i-1] == '/') mp->mnt_dir[i-1] = 0;
+               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 = (char*)"bind";
+               }
+               mp->mnt_freq = mp->mnt_passno = 0;
 
                // Write and close.
 
-               if(!mp->mnt_type || !*mp->mnt_type) mp->mnt_type="--bind";
                addmntent(mountTable, mp);
                endmntent(mountTable);
-               if (ENABLE_FEATURE_CLEAN_UP)
-                       if(strcmp(mp->mnt_type,"--bind")) mp->mnt_type = 0;
+               if (ENABLE_FEATURE_CLEAN_UP) {
+                       free(mp->mnt_dir);
+                       free(fsname);
+               }
        }
-
+ ret:
        return rc;
 }
 
+#if ENABLE_FEATURE_MOUNT_NFS
 
-// Mount one directory.  Handles NFS, loopback, autobind, and filesystem type
-// detection.  Returns 0 for success, nonzero for failure.
+/*
+ * Linux NFS mount
+ * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ *
+ * Wed Feb  8 12:51:48 1995, biro@yggdrasil.com (Ross Biro): allow all port
+ * numbers to be specified on the command line.
+ *
+ * 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.
+ *
+ * Wed Oct  1 23:55:28 1997: Dick Streefland <dick_streefland@tasking.com>
+ * Implemented the "bg", "fg" and "retry" mount options for NFS.
+ *
+ * 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org>
+ * - added Native Language Support
+ *
+ * Modified by Olaf Kirch and Trond Myklebust for new NFS code,
+ * plus NFSv3 stuff.
+ */
 
-static int singlemount(struct mntent *mp, int ignore_busy)
+#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;
+
+struct mountres3 {
+       mountstat3 fhs_status;
+       union {
+               mountres3_ok mountinfo;
+       } mountres3_u;
+};
+typedef struct mountres3 mountres3;
+
+typedef char *dirpath;
+
+typedef char *name;
+
+typedef struct mountbody *mountlist;
+
+struct mountbody {
+       name ml_hostname;
+       dirpath ml_directory;
+       mountlist ml_next;
+};
+typedef struct mountbody mountbody;
+
+typedef struct groupnode *groups;
+
+struct groupnode {
+       name gr_name;
+       groups gr_next;
+};
+typedef struct groupnode groupnode;
+
+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;
+       uint8_t 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
+
+#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
+};
+
+/*
+ * 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).
+ */
+
+struct nfs2_fh {
+       char                    data[32];
+};
+struct nfs3_fh {
+       unsigned short          size;
+       unsigned char           data[64];
+};
+
+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 */
+       NFS_MOUNT_NORDIRPLUS = 0x4000
+};
+
+
+/*
+ * 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
+/* Convert each NFSERR_BLAH into EBLAH */
+static const uint8_t nfs_err_stat[] = {
+        1,  2,  5,  6, 13, 17,
+       19, 20, 21, 22, 27, 28,
+       30, 63, 66, 69, 70, 71
+};
+#if ( \
+       EPERM | ENOENT      | EIO      | ENXIO | EACCES| EEXIST | \
+       ENODEV| ENOTDIR     | EISDIR   | EINVAL| EFBIG | ENOSPC | \
+       EROFS | ENAMETOOLONG| ENOTEMPTY| EDQUOT| ESTALE| EREMOTE) < 256
+typedef uint8_t nfs_err_type;
+#else
+typedef uint16_t nfs_err_type;
+#endif
+static const nfs_err_type nfs_err_errnum[] = {
+       EPERM , ENOENT      , EIO      , ENXIO , EACCES, EEXIST,
+       ENODEV, ENOTDIR     , EISDIR   , EINVAL, EFBIG , ENOSPC,
+       EROFS , ENAMETOOLONG, ENOTEMPTY, EDQUOT, ESTALE, EREMOTE
+};
+static char *nfs_strerror(int status)
 {
-       int rc = -1, vfsflags;
-       char *loopFile = 0, *filteropts = 0;
-       llist_t *fl = 0;
-       struct stat st;
+       int i;
 
-       vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);
+       for (i = 0; i < ARRAY_SIZE(nfs_err_stat); i++) {
+               if (nfs_err_stat[i] == status)
+                       return strerror(nfs_err_errnum[i]);
+       }
+       return xasprintf("unknown nfs status return value: %d", status);
+}
 
-       // Treat fstype "auto" as unspecified.
+static bool_t xdr_fhandle(XDR *xdrs, fhandle objp)
+{
+       if (!xdr_opaque(xdrs, objp, FHSIZE))
+                return FALSE;
+       return TRUE;
+}
 
-       if (mp->mnt_type && !strcmp(mp->mnt_type,"auto")) mp->mnt_type = 0;
+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;
+}
 
-       // Might this be an NFS filesystem?
+static bool_t xdr_dirpath(XDR *xdrs, dirpath *objp)
+{
+       if (!xdr_string(xdrs, objp, MNTPATHLEN))
+                return FALSE;
+       return 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;
+}
+
+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;
+}
+
+#define MAX_NFSPROT ((nfs_mount_version >= 4) ? 3 : 2)
+
+/*
+ * 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)
+{
+       int kernel_version;
+
+       if (nfs_mount_version)
+               return;
+
+       nfs_mount_version = 4; /* default */
+
+       kernel_version = get_linux_version_code();
+       if (kernel_version) {
+               if (kernel_version < KERNEL_VERSION(2,2,18))
+                       nfs_mount_version = 3;
+               /* else v4 since 2.3.99pre4 */
+       }
+}
+
+static void
+get_mountport(struct pmap *pm_mnt,
+       struct sockaddr_in *server_addr,
+       long unsigned prog,
+       long unsigned version,
+       long unsigned proto,
+       long unsigned port)
+{
+       struct pmaplist *pmap;
+
+       server_addr->sin_port = PMAPPORT;
+/* glibc 2.4 (still) has pmap_getmaps(struct sockaddr_in *).
+ * I understand it like "IPv6 for this is not 100% ready" */
+       pmap = pmap_getmaps(server_addr);
+
+       if (version > MAX_NFSPROT)
+               version = MAX_NFSPROT;
+       if (!prog)
+               prog = MOUNTPROG;
+       pm_mnt->pm_prog = prog;
+       pm_mnt->pm_vers = version;
+       pm_mnt->pm_prot = proto;
+       pm_mnt->pm_port = port;
+
+       while (pmap) {
+               if (pmap->pml_map.pm_prog != prog)
+                       goto next;
+               if (!version && pm_mnt->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 && pm_mnt->pm_prot && pmap->pml_map.pm_prot != proto)
+                || (port && pmap->pml_map.pm_port != port)
+               ) {
+                       goto next;
+               }
+               memcpy(pm_mnt, &pmap->pml_map, sizeof(*pm_mnt));
+ next:
+               pmap = pmap->pml_next;
+       }
+       if (!pm_mnt->pm_vers)
+               pm_mnt->pm_vers = MOUNTVERS;
+       if (!pm_mnt->pm_port)
+               pm_mnt->pm_port = MOUNTPORT;
+       if (!pm_mnt->pm_prot)
+               pm_mnt->pm_prot = IPPROTO_TCP;
+}
 
-       if (ENABLE_FEATURE_MOUNT_NFS &&
-               (!mp->mnt_type || !strcmp(mp->mnt_type,"nfs")) &&
-               strchr(mp->mnt_fsname, ':') != NULL)
+#if BB_MMU
+static int daemonize(void)
+{
+       int pid = fork();
+       if (pid < 0) /* error */
+               return -errno;
+       if (pid > 0) /* parent */
+               return 0;
+       /* child */
+       close(0);
+       xopen(bb_dev_null, O_RDWR);
+       xdup2(0, 1);
+       xdup2(0, 2);
+       setsid();
+       openlog(applet_name, LOG_PID, LOG_DAEMON);
+       logmode = LOGMODE_SYSLOG;
+       return 1;
+}
+#else
+static inline int daemonize(void) { return -ENOSYS; }
+#endif
+
+/* TODO */
+static inline int we_saw_this_host_before(const char *hostname UNUSED_PARAM)
+{
+       return 0;
+}
+
+/* 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)
+{
+       int len;
+       while (msg[0] == ' ' || msg[0] == ':') msg++;
+       len = strlen(msg);
+       while (len && msg[len-1] == '\n') len--;
+       bb_error_msg("%.*s", len, msg);
+}
+
+/* NB: mp->xxx fields may be trashed on exit */
+static NOINLINE int nfsmount(struct mntent *mp, long vfsflags, char *filteropts)
+{
+       CLIENT *mclient;
+       char *hostname;
+       char *pathname;
+       char *mounthost;
+       /* prior to 2.6.23, kernel took NFS options in a form of this struct
+        * only. 2.6.23+ looks at data->version, and if it's not 1..6,
+        * then data pointer is interpreted as a string. */
+       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;
+#if BB_MMU
+       smallint bg = 0;
+#else
+       enum { bg = 0 };
+#endif
+       int retry;
+       int mountprog;
+       int mountvers;
+       int nfsprog;
+       int nfsvers;
+       int retval;
+       /* these all are one-bit really. gcc 4.3.1 likes this combination: */
+       smallint tcp;
+       smallint soft;
+       int intr;
+       int posix;
+       int nocto;
+       int noac;
+       int nordirplus;
+       int nolock;
+
+       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 != (int)sizeof(struct in_addr)) {
+                       bb_error_msg_and_die("only IPv4 is supported");
+               }
+               memcpy(&server_addr.sin_addr, hp->h_addr_list[0], sizeof(struct in_addr));
+       }
+
+       memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));
+
+       /* 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;
+
+       soft = 0;
+       intr = 0;
+       posix = 0;
+       nocto = 0;
+       nolock = 0;
+       noac = 0;
+       nordirplus = 0;
+       retry = 10000;          /* 10000 minutes ~ 1 week */
+       tcp = 0;
+
+       mountprog = MOUNTPROG;
+       mountvers = 0;
+       port = 0;
+       mountport = 0;
+       nfsprog = 100003;
+       nfsvers = 0;
+
+       /* parse options */
+       if (filteropts) for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
+               char *opteq = strchr(opt, '=');
+               if (opteq) {
+                       int val, idx;
+                       static const char options[] ALIGN1 =
+                               /* 0 */ "rsize\0"
+                               /* 1 */ "wsize\0"
+                               /* 2 */ "timeo\0"
+                               /* 3 */ "retrans\0"
+                               /* 4 */ "acregmin\0"
+                               /* 5 */ "acregmax\0"
+                               /* 6 */ "acdirmin\0"
+                               /* 7 */ "acdirmax\0"
+                               /* 8 */ "actimeo\0"
+                               /* 9 */ "retry\0"
+                               /* 10 */ "port\0"
+                               /* 11 */ "mountport\0"
+                               /* 12 */ "mounthost\0"
+                               /* 13 */ "mountprog\0"
+                               /* 14 */ "mountvers\0"
+                               /* 15 */ "nfsprog\0"
+                               /* 16 */ "nfsvers\0"
+                               /* 17 */ "vers\0"
+                               /* 18 */ "proto\0"
+                               /* 19 */ "namlen\0"
+                               /* 20 */ "addr\0";
+
+                       *opteq++ = '\0';
+                       idx = index_in_strings(options, opt);
+                       switch (idx) {
+                       case 12: // "mounthost"
+                               mounthost = xstrndup(opteq,
+                                               strcspn(opteq, " \t\n\r,"));
+                               continue;
+                       case 18: // "proto"
+                               if (!strncmp(opteq, "tcp", 3))
+                                       tcp = 1;
+                               else if (!strncmp(opteq, "udp", 3))
+                                       tcp = 0;
+                               else
+                                       bb_error_msg("warning: unrecognized proto= option");
+                               continue;
+                       case 20: // "addr" - ignore
+                               continue;
+                       }
+
+                       val = xatoi_positive(opteq);
+                       switch (idx) {
+                       case 0: // "rsize"
+                               data.rsize = val;
+                               continue;
+                       case 1: // "wsize"
+                               data.wsize = val;
+                               continue;
+                       case 2: // "timeo"
+                               data.timeo = val;
+                               continue;
+                       case 3: // "retrans"
+                               data.retrans = val;
+                               continue;
+                       case 4: // "acregmin"
+                               data.acregmin = val;
+                               continue;
+                       case 5: // "acregmax"
+                               data.acregmax = val;
+                               continue;
+                       case 6: // "acdirmin"
+                               data.acdirmin = val;
+                               continue;
+                       case 7: // "acdirmax"
+                               data.acdirmax = val;
+                               continue;
+                       case 8: // "actimeo"
+                               data.acregmin = val;
+                               data.acregmax = val;
+                               data.acdirmin = val;
+                               data.acdirmax = val;
+                               continue;
+                       case 9: // "retry"
+                               retry = val;
+                               continue;
+                       case 10: // "port"
+                               port = val;
+                               continue;
+                       case 11: // "mountport"
+                               mountport = val;
+                               continue;
+                       case 13: // "mountprog"
+                               mountprog = val;
+                               continue;
+                       case 14: // "mountvers"
+                               mountvers = val;
+                               continue;
+                       case 15: // "nfsprog"
+                               nfsprog = val;
+                               continue;
+                       case 16: // "nfsvers"
+                       case 17: // "vers"
+                               nfsvers = val;
+                               continue;
+                       case 19: // "namlen"
+                               //if (nfs_mount_version >= 2)
+                                       data.namlen = val;
+                               //else
+                               //      bb_error_msg("warning: option namlen is not supported\n");
+                               continue;
+                       default:
+                               bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
+                               goto fail;
+                       }
+               }
+               else { /* not of the form opt=val */
+                       static const char options[] ALIGN1 =
+                               "bg\0"
+                               "fg\0"
+                               "soft\0"
+                               "hard\0"
+                               "intr\0"
+                               "posix\0"
+                               "cto\0"
+                               "ac\0"
+                               "tcp\0"
+                               "udp\0"
+                               "lock\0"
+                               "rdirplus\0";
+                       int val = 1;
+                       if (!strncmp(opt, "no", 2)) {
+                               val = 0;
+                               opt += 2;
+                       }
+                       switch (index_in_strings(options, opt)) {
+                       case 0: // "bg"
+#if BB_MMU
+                               bg = val;
+#endif
+                               break;
+                       case 1: // "fg"
+#if BB_MMU
+                               bg = !val;
+#endif
+                               break;
+                       case 2: // "soft"
+                               soft = val;
+                               break;
+                       case 3: // "hard"
+                               soft = !val;
+                               break;
+                       case 4: // "intr"
+                               intr = val;
+                               break;
+                       case 5: // "posix"
+                               posix = val;
+                               break;
+                       case 6: // "cto"
+                               nocto = !val;
+                               break;
+                       case 7: // "ac"
+                               noac = !val;
+                               break;
+                       case 8: // "tcp"
+                               tcp = val;
+                               break;
+                       case 9: // "udp"
+                               tcp = !val;
+                               break;
+                       case 10: // "lock"
+                               if (nfs_mount_version >= 3)
+                                       nolock = !val;
+                               else
+                                       bb_error_msg("warning: option nolock is not supported");
+                               break;
+                       case 11: //rdirplus
+                               nordirplus = !val;
+                               break;
+                       default:
+                               bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
+                               goto fail;
+                       }
+               }
+       }
+       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)
+               | (nordirplus ? NFS_MOUNT_NORDIRPLUS : 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();
+               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 {
+                       hp = gethostbyname(mounthost);
+                       if (hp == NULL) {
+                               bb_herror_msg("%s", mounthost);
+                               goto fail;
+                       }
+                       if (hp->h_length != (int)sizeof(struct in_addr)) {
+                               bb_error_msg_and_die("only IPv4 is supported");
+                       }
+                       mount_server_addr.sin_family = AF_INET;
+                       memcpy(&mount_server_addr.sin_addr, hp->h_addr_list[0], sizeof(struct in_addr));
+               }
+       }
+
+       /*
+        * 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.
+        */
        {
-               if (nfsmount(mp->mnt_fsname, mp->mnt_dir, &vfsflags, &filteropts, 1)) {
-                       bb_perror_msg("nfsmount failed");
-                       goto report_error;
+               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;
+/* FIXME: use monotonic()? */
+               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);
+
+               get_mountport(&pm_mnt, &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 = NULL;
+               }
+               if (!mclient) {
+                       if (!daemonized && prevt == 0)
+                               error_msg_rpc(clnt_spcreateerror(" "));
                } else {
-                       // Strangely enough, nfsmount() doesn't actually mount() anything.
-                       mp->mnt_type = "nfs";
-                       rc = mount_it_now(mp, vfsflags, filteropts);
-                       if (ENABLE_FEATURE_CLEAN_UP) free(filteropts);
-                       
-                       goto report_error;
+                       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 */
+                       }
+                       /* Connection refused */
+                       if (!daemonized && prevt == 0) /* print just once */
+                               error_msg_rpc(clnt_sperror(mclient, " "));
+                       auth_destroy(mclient->cl_auth);
+                       clnt_destroy(mclient);
+                       mclient = NULL;
+                       close(msock);
+                       msock = -1;
+               }
+
+               /* 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;
+                       }
                }
+               prevt = t;
+               t = time(NULL);
+               if (t >= timeout)
+                       /* TODO error message */
+                       goto fail;
+
+               goto retry;
        }
 
-       // Look at the file.  (Not found isn't a failure for remount, or for
-       // a synthetic filesystem like proc or sysfs.)
+ prepare_kernel_data:
 
-       if (lstat(mp->mnt_fsname, &st));
-       else if (!(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))) {
-               // Do we need to allocate a loopback device for it?
+       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 {
+               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 (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
-                                               : "Couldn't setup loop device");
-                                       return errno;
+       /* Create nfs socket for kernel */
+       if (tcp) {
+               if (nfs_mount_version < 3) {
+                       bb_error_msg("NFS over TCP is not supported");
+                       goto fail;
+               }
+               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;
+       }
+       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);
+
+       /* Prepare data structure for kernel */
+       data.fd = fsock;
+       memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
+       strncpy(data.hostname, hostname, sizeof(data.hostname));
+
+       /* Clean up */
+       auth_destroy(mclient->cl_auth);
+       clnt_destroy(mclient);
+       close(msock);
+       msock = -1;
+
+       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 */
+/* FIXME: parent doesn't close fsock - ??! */
+                                       retval = -daemonized;
+                                       goto ret;
+                               }
                        }
+                       sleep(delay);   /* 1, 2, 4, 8, 16, 30, ... */
+                       delay *= 2;
+                       if (delay > 30)
+                               delay = 30;
+               }
+       }
 
-               // Autodetect bind mounts
+       /* Perform actual mount */
+ do_mount:
+       mp->mnt_type = (char*)"nfs";
+       retval = mount_it_now(mp, vfsflags, (char*)&data);
+       goto ret;
+
+       /* Abort */
+ fail:
+       if (msock >= 0) {
+               if (mclient) {
+                       auth_destroy(mclient->cl_auth);
+                       clnt_destroy(mclient);
+               }
+               close(msock);
+       }
+       if (fsock >= 0)
+               close(fsock);
+
+ ret:
+       free(hostname);
+       free(mounthost);
+       free(filteropts);
+       return retval;
+}
+
+#else // !ENABLE_FEATURE_MOUNT_NFS
+
+// Never called. Call should be optimized out.
+int nfsmount(struct mntent *mp, long vfsflags, char *filteropts);
 
-               } else if (S_ISDIR(st.st_mode) && !mp->mnt_type) vfsflags |= MS_BIND;
+#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)
+{
+       int rc = -1;
+       long vfsflags;
+       char *loopFile = NULL, *filteropts = NULL;
+       llist_t *fl = NULL;
+       struct stat st;
+
+       errno = 0;
+
+       vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);
+
+       // Treat fstype "auto" as unspecified
+       if (mp->mnt_type && strcmp(mp->mnt_type, "auto") == 0)
+               mp->mnt_type = NULL;
+
+       // Might this be a virtual filesystem?
+       if (ENABLE_FEATURE_MOUNT_HELPERS && strchr(mp->mnt_fsname, '#')) {
+               char *args[35];
+               char *s;
+               int n;
+               // fsname: "cmd#arg1#arg2..."
+               // WARNING: allows execution of arbitrary commands!
+               // Try "mount 'sh#-c#sh' bogus_dir".
+               // It is safe ONLY because non-root
+               // cannot use two-argument mount command
+               // and using one-argument "mount 'sh#-c#sh'" doesn't work:
+               // "mount: can't find sh#-c#sh in /etc/fstab"
+               // (if /etc/fstab has it, it's ok: root sets up /etc/fstab).
+
+               s = mp->mnt_fsname;
+               n = 0;
+               args[n++] = s;
+               while (*s && n < 35 - 2) {
+                       if (*s++ == '#' && *s != '#') {
+                               s[-1] = '\0';
+                               args[n++] = s;
+                       }
+               }
+               args[n++] = mp->mnt_dir;
+               args[n] = NULL;
+               rc = spawn_and_wait(args);
+               goto report_error;
        }
 
-       /* If we know the fstype (or don't need to), jump straight
-        * to the actual mount. */
+       // Might this be an CIFS filesystem?
+       if (ENABLE_FEATURE_MOUNT_CIFS
+        && (!mp->mnt_type || strcmp(mp->mnt_type, "cifs") == 0)
+        && (mp->mnt_fsname[0] == '/' || mp->mnt_fsname[0] == '\\')
+        && mp->mnt_fsname[0] == mp->mnt_fsname[1]
+       ) {
+               int len;
+               char c;
+               len_and_sockaddr *lsa;
+               char *hostname, *dotted, *ip;
+
+               hostname = mp->mnt_fsname + 2;
+               len = strcspn(hostname, "/\\");
+               if (len == 0 || hostname[len] == '\0')
+                       goto report_error;
+               c = hostname[len];
+               hostname[len] = '\0';
+               lsa = host2sockaddr(hostname, 0);
+               hostname[len] = c;
+               if (!lsa)
+                       goto report_error;
 
-       if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
+               // Insert "ip=..." option into options
+               dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
+               if (ENABLE_FEATURE_CLEAN_UP) free(lsa);
+               ip = xasprintf("ip=%s", dotted);
+               if (ENABLE_FEATURE_CLEAN_UP) free(dotted);
+               parse_mount_options(ip, &filteropts);
+               if (ENABLE_FEATURE_CLEAN_UP) free(ip);
+
+               // "-o mand" is required [why?]
+               vfsflags |= MS_MANDLOCK;
+               mp->mnt_type = (char*)"cifs";
                rc = mount_it_now(mp, vfsflags, filteropts);
 
-       // Loop through filesystem types until mount succeeds or we run out
+               goto report_error;
+       }
+
+       // Might this be an NFS filesystem?
+       if (ENABLE_FEATURE_MOUNT_NFS
+        && (!mp->mnt_type || strcmp(mp->mnt_type, "nfs") == 0)
+        && strchr(mp->mnt_fsname, ':') != NULL
+       ) {
+               rc = nfsmount(mp, vfsflags, filteropts);
+               goto report_error;
+       }
 
-       else {
+       // Look at the file.  (Not found isn't a failure for remount, or for
+       // a synthetic filesystem like proc or sysfs.)
+       // (We use stat, not lstat, in order to allow
+       // mount symlink_to_file_or_blkdev dir)
+       if (!stat(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 = NULL; // will receive malloced loop dev name
+                       if (set_loop(&mp->mnt_fsname, loopFile, 0) < 0) {
+                               if (errno == EPERM || errno == EACCES)
+                                       bb_error_msg(bb_msg_perm_denied_are_you_root);
+                               else
+                                       bb_perror_msg("can't setup loop device");
+                               return errno;
+                       }
 
-               /* Initialize list of block backed filesystems.  This has to be
-                * done here so that during "mount -a", mounts after /proc shows up
-                * can autodetect. */
+               // 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);
+       } else {
+               // Loop through filesystem types until mount succeeds
+               // or we run out
+
+               // 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)
@@ -330,17 +1735,13 @@ static int singlemount(struct mntent *mp, int ignore_busy)
 
                for (fl = fslist; fl; fl = fl->link) {
                        mp->mnt_type = fl->data;
-
-                       if (!(rc = mount_it_now(mp,vfsflags, filteropts))) break;
-
-                       mp->mnt_type = 0;
+                       rc = mount_it_now(mp, vfsflags, filteropts);
+                       if (!rc)
+                               break;
                }
        }
 
-       if (ENABLE_FEATURE_CLEAN_UP) free(filteropts);
-
        // If mount failed, clean up loop file (if any).
-
        if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) {
                del_loop(mp->mnt_fsname);
                if (ENABLE_FEATURE_CLEAN_UP) {
@@ -348,199 +1749,345 @@ static int singlemount(struct mntent *mp, int ignore_busy)
                        free(mp->mnt_fsname);
                }
        }
-report_error:
-       if (rc && errno == EBUSY && ignore_busy) rc = 0;
-       if (rc < 0)
-               bb_perror_msg("Mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
 
+ report_error:
+       if (ENABLE_FEATURE_CLEAN_UP)
+               free(filteropts);
+
+       if (errno == EBUSY && ignore_busy)
+               return 0;
+       if (rc != 0)
+               bb_perror_msg("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
        return rc;
 }
 
+// -O support
+//    -O interprets a list of filter options which select whether a mount
+// point will be mounted: only mounts with options matching *all* filtering
+// options will be selected.
+//    By default each -O filter option must be present in the list of mount
+// options, but if it is prefixed by "no" then it must be absent.
+// For example,
+//  -O a,nob,c  matches  -o a,c  but fails to match  -o a,b,c
+//              (and also fails to match  -o a  because  -o c  is absent).
+//
+// It is different from -t in that each option is matched exactly; a leading
+// "no" at the beginning of one option does not negate the rest.
+static int match_opt(const char *fs_opt_in, const char *O_opt)
+{
+       if (!O_opt)
+               return 1;
+
+       while (*O_opt) {
+               const char *fs_opt = fs_opt_in;
+               int O_len;
+               int match;
+
+               // If option begins with "no" then treat as an inverted match:
+               // matching is a failure
+               match = 0;
+               if (O_opt[0] == 'n' && O_opt[1] == 'o') {
+                       match = 1;
+                       O_opt += 2;
+               }
+               // Isolate the current O option
+               O_len = strchrnul(O_opt, ',') - O_opt;
+               // Check for a match against existing options
+               while (1) {
+                       if (strncmp(fs_opt, O_opt, O_len) == 0
+                        && (fs_opt[O_len] == '\0' || fs_opt[O_len] == ',')
+                       ) {
+                               if (match)
+                                       return 0;  // "no" prefix, but option found
+                               match = 1;  // current O option found, go check next one
+                               break;
+                       }
+                       fs_opt = strchr(fs_opt, ',');
+                       if (!fs_opt)
+                               break;
+                       fs_opt++;
+               }
+               if (match == 0)
+                       return 0;     // match wanted but not found
+               if (O_opt[O_len] == '\0') // end?
+                       break;
+               // Step to the next O option
+               O_opt += O_len + 1;
+       }
+       // If we get here then everything matched
+       return 1;
+}
+
 // Parse options, if necessary parse fstab/mtab, and call singlemount for
 // each directory to be mounted.
-
-int mount_main(int argc, char **argv)
+int mount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int mount_main(int argc UNUSED_PARAM, char **argv)
 {
-       char *cmdopts = xstrdup(""), *fstabname, *fstype=0, *storage_path=0;
+       char *cmdopts = xzalloc(1);
+       char *fstype = NULL;
+       char *O_optmatch = NULL;
+       char *storage_path;
+       llist_t *lst_o = NULL;
+       const char *fstabname;
        FILE *fstab;
-       int i, opt, all = FALSE, rc = 0;
+       int i, j;
+       int rc = EXIT_SUCCESS;
+       unsigned opt;
        struct mntent mtpair[2], *mtcur = mtpair;
+       IF_NOT_DESKTOP(const int nonroot = 0;)
 
-       /* parse long options, like --bind and --move.  Note that -o option
-        * and --option are synonymous.  Yes, this means --remount,rw works. */
+       IF_DESKTOP(int nonroot = ) sanitize_env_if_suid();
 
-       for (i = opt = 0; i < argc; i++) {
-               if (argv[i][0] == '-' && argv[i][1] == '-') {
-                       append_mount_options(&cmdopts,argv[i]+2);
-               } else argv[opt++] = argv[i];
+       // Parse long options, like --bind and --move.  Note that -o option
+       // and --option are synonymous.  Yes, this means --remount,rw works.
+       for (i = j = 1; argv[i]; i++) {
+               if (argv[i][0] == '-' && argv[i][1] == '-')
+                       append_mount_options(&cmdopts, argv[i] + 2);
+               else
+                       argv[j++] = argv[i];
        }
-       argc = opt;
+       argv[j] = NULL;
 
        // Parse remaining options
-
-       while ((opt = getopt(argc, argv, "o:t:rwavnf")) > 0) {
-               switch (opt) {
-                       case 'o':
-                               append_mount_options(&cmdopts, optarg);
-                               break;
-                       case 't':
-                               fstype = optarg;
-                               break;
-                       case 'r':
-                               append_mount_options(&cmdopts, "ro");
-                               break;
-                       case 'w':
-                               append_mount_options(&cmdopts, "rw");
-                               break;
-                       case 'a':
-                               all = TRUE;
-                               break;
-                       case 'n':
-                               USE_FEATURE_MTAB_SUPPORT(useMtab = FALSE;)
-                               break;
-                       case 'f':
-                               USE_FEATURE_MTAB_SUPPORT(fakeIt = FALSE;)
-                               break;
-                       case 'v':
-                               break;          // ignore -v
-                       default:
-                               bb_show_usage();
-               }
-       }
-
-       // Three or more non-option arguments?  Die with a usage message.
-
-       if (optind-argc>2) bb_show_usage();
+       // Max 2 params; -o is a list, -v is a counter
+       opt_complementary = "?2o::" IF_FEATURE_MOUNT_VERBOSE("vv");
+       opt = getopt32(argv, OPTION_STR, &lst_o, &fstype, &O_optmatch
+                       IF_FEATURE_MOUNT_VERBOSE(, &verbose));
+       while (lst_o) append_mount_options(&cmdopts, llist_pop(&lst_o)); // -o
+       if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
+       if (opt & OPT_w) append_mount_options(&cmdopts, "rw"); // -w
+       argv += optind;
 
        // If we have no arguments, show currently mounted filesystems
-
-       if (optind == argc) {
-               if (!all) {
+       if (!argv[0]) {
+               if (!(opt & OPT_a)) {
                        FILE *mountTable = setmntent(bb_path_mtab_file, "r");
 
-                       if(!mountTable) bb_error_msg_and_die("No %s",bb_path_mtab_file);
+                       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)))
+                       while (getmntent_r(mountTable, &mtpair[0], getmntent_buf,
+                                                               GETMNTENT_BUFSIZE))
                        {
-                               // Don't show rootfs.
-                               if (!strcmp(mtpair->mnt_fsname, "rootfs")) continue;
+                               // Don't show rootfs. FIXME: why??
+                               // util-linux 2.12a happily shows rootfs...
+                               //if (strcmp(mtpair->mnt_fsname, "rootfs") == 0) continue;
 
-                               if (!fstype || !strcmp(mtpair->mnt_type, fstype))
+                               if (!fstype || strcmp(mtpair->mnt_type, fstype) == 0)
                                        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);
+                       if (ENABLE_FEATURE_CLEAN_UP)
+                               endmntent(mountTable);
                        return EXIT_SUCCESS;
                }
+               storage_path = NULL;
+       } else {
+               // 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 (argv[1]) {
+                       if (nonroot)
+                               bb_error_msg_and_die(bb_msg_you_must_be_root);
+                       mtpair->mnt_fsname = argv[0];
+                       mtpair->mnt_dir = argv[1];
+                       mtpair->mnt_type = fstype;
+                       mtpair->mnt_opts = cmdopts;
+                       resolve_mount_spec(&mtpair->mnt_fsname);
+                       rc = singlemount(mtpair, /*ignore_busy:*/ 0);
+                       return rc;
+               }
+               storage_path = bb_simplify_path(argv[0]); // malloced
        }
 
-       // 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 (optind+2 == argc) {
-               mtpair->mnt_fsname = argv[optind];
-               mtpair->mnt_dir = argv[optind+1];
-               mtpair->mnt_type = fstype;
-               mtpair->mnt_opts = cmdopts;
-               rc = singlemount(mtpair, 0);
-               goto clean_up;
+       // Past this point, we are handling either "mount -a [opts]"
+       // or "mount [opts] single_param"
+
+       i = parse_mount_options(cmdopts, NULL); // FIXME: should be "long", not "int"
+       if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
+               bb_error_msg_and_die(bb_msg_you_must_be_root);
+
+       // 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))
+       ) {
+               // verbose_mount(source, target, type, flags, data)
+               rc = verbose_mount("", argv[0], "", i, "");
+               if (rc)
+                       bb_simple_perror_msg_and_die(argv[0]);
+               return rc;
        }
 
-       // If we have at least one argument, it's the storage location
-
-       if (optind < argc) storage_path = bb_simplify_path(argv[optind]);
-
        // Open either fstab or mtab
+       fstabname = "/etc/fstab";
+       if (i & MS_REMOUNT) {
+               // WARNING. I am not sure this matches util-linux's
+               // behavior. It's possible util-linux does not
+               // take -o opts from mtab (takes only mount source).
+               fstabname = bb_path_mtab_file;
+       }
+       fstab = setmntent(fstabname, "r");
+       if (!fstab)
+               bb_perror_msg_and_die("can't read '%s'", fstabname);
 
-       if (parse_mount_options(cmdopts,0) & MS_REMOUNT)
-               fstabname = (char *)bb_path_mtab_file;  // Again with the evil const.
-       else fstabname="/etc/fstab";
-
-       if (!(fstab=setmntent(fstabname,"r")))
-               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));
+       // Loop through entries until we find what we're looking for
+       memset(mtpair, 0, sizeof(mtpair));
        for (;;) {
-               struct mntent *mtnext = mtpair + (mtcur==mtpair ? 1 : 0);
+               struct mntent *mtother = (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 (optind != argc) {
-
-                               // If we didn't find anything, complain.
-
-                               if (!mtnext->mnt_fsname)
-                                       bb_error_msg_and_die("Can't find %s in %s",
-                                               argv[optind], 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 (!getmntent_r(fstab, mtcur, getmntent_buf
+                                       + (mtcur==mtpair ? GETMNTENT_BUFSIZE/2 : 0),
+                               GETMNTENT_BUFSIZE/2)
+               ) { // End of fstab/mtab is reached
+                       mtcur = mtother; // the thing we found last time
+                       break;
                }
 
-               /* 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 (optind != argc) {
+               // If we're trying to mount something specific and this isn't it,
+               // skip it.  Note we must match the exact text in fstab (ala
+               // "proc") or a full path from root
+               if (argv[0]) {
 
                        // Is this what we're looking for?
+                       if (strcmp(argv[0], mtcur->mnt_fsname) != 0
+                        && strcmp(storage_path, mtcur->mnt_fsname) != 0
+                        && strcmp(argv[0], mtcur->mnt_dir) != 0
+                        && strcmp(storage_path, mtcur->mnt_dir) != 0
+                       ) {
+                               continue; // no
+                       }
 
-                       if(strcmp(argv[optind],mtcur->mnt_fsname) &&
-                          strcmp(storage_path,mtcur->mnt_fsname) &&
-                          strcmp(argv[optind],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.
+                       // Remember this entry.  Something later may have
+                       // overmounted it, and we want the _last_ match.
+                       mtcur = mtother;
 
+               // If we're mounting all
                } else {
+                       struct mntent *mp;
+                       // No, mount -a won't mount anything,
+                       // even user mounts, for mere humans
+                       if (nonroot)
+                               bb_error_msg_and_die(bb_msg_you_must_be_root);
+
+                       // Does type match? (NULL matches always)
+                       if (!match_fstype(mtcur, fstype))
+                               continue;
+
+                       // Skip noauto and swap anyway
+                       if ((parse_mount_options(mtcur->mnt_opts, NULL) & (MOUNT_NOAUTO | MOUNT_SWAP))
+                       // swap is bogus "fstype", parse_mount_options can't check fstypes
+                        || strcasecmp(mtcur->mnt_type, "swap") == 0
+                       ) {
+                               continue;
+                       }
 
-                       // 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++;
+                       // Does (at least one) option match?
+                       // (NULL matches always)
+                       if (!match_opt(mtcur->mnt_opts, O_optmatch))
+                               continue;
+
+                       resolve_mount_spec(&mtcur->mnt_fsname);
+
+                       // NFS mounts want this to be xrealloc-able
+                       mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
+
+                       // If nothing is mounted on this directory...
+                       // (otherwise repeated "mount -a" mounts everything again)
+                       mp = find_mount_point(mtcur->mnt_dir, /*subdir_too:*/ 0);
+                       // We do not check fsname match of found mount point -
+                       // "/" may have fsname of "/dev/root" while fstab
+                       // says "/dev/something_else".
+                       if (mp) {
+                               if (verbose) {
+                                       bb_error_msg("according to %s, "
+                                               "%s is already mounted on %s",
+                                               bb_path_mtab_file,
+                                               mp->mnt_fsname, mp->mnt_dir);
+                               }
+                       } else {
+                               // ...mount this thing
+                               if (singlemount(mtcur, /*ignore_busy:*/ 1)) {
+                                       // Count number of failed mounts
+                                       rc++;
+                               }
                        }
+                       free(mtcur->mnt_opts);
                }
        }
-       if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);
 
-clean_up:
+       // End of fstab/mtab is reached.
+       // Were we looking for something specific?
+       if (argv[0]) { // yes
+               long l;
+
+               // If we didn't find anything, complain
+               if (!mtcur->mnt_fsname)
+                       bb_error_msg_and_die("can't find %s in %s",
+                               argv[0], fstabname);
+
+               // What happens when we try to "mount swap_partition"?
+               // (fstab containts "swap_partition swap swap defaults 0 0")
+               // util-linux-ng 2.13.1 does this:
+               // stat("/sbin/mount.swap", 0x7fff62a3a350) = -1 ENOENT (No such file or directory)
+               // mount("swap_partition", "swap", "swap", MS_MGC_VAL, NULL) = -1 ENOENT (No such file or directory)
+               // lstat("swap", 0x7fff62a3a640)           = -1 ENOENT (No such file or directory)
+               // write(2, "mount: mount point swap does not exist\n", 39) = 39
+               // exit_group(32)                          = ?
+#if 0
+               // In case we want to simply skip swap partitions:
+               l = parse_mount_options(mtcur->mnt_opts, NULL);
+               if ((l & MOUNT_SWAP)
+               // swap is bogus "fstype", parse_mount_options can't check fstypes
+                || strcasecmp(mtcur->mnt_type, "swap") == 0
+               ) {
+                       goto ret;
+               }
+#endif
+               if (nonroot) {
+                       // fstab must have "users" or "user"
+                       l = parse_mount_options(mtcur->mnt_opts, NULL);
+                       if (!(l & MOUNT_USERS))
+                               bb_error_msg_and_die(bb_msg_you_must_be_root);
+               }
+
+               //util-linux-2.12 does not do this check.
+               //// If nothing is mounted on this directory...
+               //// (otherwise repeated "mount FOO" mounts FOO again)
+               //mp = find_mount_point(mtcur->mnt_dir, /*subdir_too:*/ 0);
+               //if (mp) {
+               //      bb_error_msg("according to %s, "
+               //              "%s is already mounted on %s",
+               //              bb_path_mtab_file,
+               //              mp->mnt_fsname, mp->mnt_dir);
+               //} else {
+                       // ...mount the last thing we found
+                       mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
+                       append_mount_options(&(mtcur->mnt_opts), cmdopts);
+                       resolve_mount_spec(&mtpair->mnt_fsname);
+                       rc = singlemount(mtcur, /*ignore_busy:*/ 0);
+                       if (ENABLE_FEATURE_CLEAN_UP)
+                               free(mtcur->mnt_opts);
+               //}
+       }
 
+ //ret:
+       if (ENABLE_FEATURE_CLEAN_UP)
+               endmntent(fstab);
        if (ENABLE_FEATURE_CLEAN_UP) {
                free(storage_path);
                free(cmdopts);
        }
 
+//TODO: exitcode should be ORed mask of (from "man mount"):
+// 0 success
+// 1 incorrect invocation or permissions
+// 2 system error (out of memory, cannot fork, no more loop devices)
+// 4 internal mount bug or missing nfs support in mount
+// 8 user interrupt
+//16 problems writing or locking /etc/mtab
+//32 mount failure
+//64 some mount succeeded
        return rc;
 }