linux/fs/autofs/inode.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   4 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
   5 */
   6
   7#include <linux/seq_file.h>
   8#include <linux/pagemap.h>
   9#include <linux/parser.h>
  10
  11#include "autofs_i.h"
  12
  13struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
  14{
  15        struct autofs_info *ino;
  16
  17        ino = kzalloc(sizeof(*ino), GFP_KERNEL);
  18        if (ino) {
  19                INIT_LIST_HEAD(&ino->active);
  20                INIT_LIST_HEAD(&ino->expiring);
  21                ino->last_used = jiffies;
  22                ino->sbi = sbi;
  23        }
  24        return ino;
  25}
  26
  27void autofs_clean_ino(struct autofs_info *ino)
  28{
  29        ino->uid = GLOBAL_ROOT_UID;
  30        ino->gid = GLOBAL_ROOT_GID;
  31        ino->last_used = jiffies;
  32}
  33
  34void autofs_free_ino(struct autofs_info *ino)
  35{
  36        kfree_rcu(ino, rcu);
  37}
  38
  39void autofs_kill_sb(struct super_block *sb)
  40{
  41        struct autofs_sb_info *sbi = autofs_sbi(sb);
  42
  43        /*
  44         * In the event of a failure in get_sb_nodev the superblock
  45         * info is not present so nothing else has been setup, so
  46         * just call kill_anon_super when we are called from
  47         * deactivate_super.
  48         */
  49        if (sbi) {
  50                /* Free wait queues, close pipe */
  51                autofs_catatonic_mode(sbi);
  52                put_pid(sbi->oz_pgrp);
  53        }
  54
  55        pr_debug("shutting down\n");
  56        kill_litter_super(sb);
  57        if (sbi)
  58                kfree_rcu(sbi, rcu);
  59}
  60
  61static int autofs_show_options(struct seq_file *m, struct dentry *root)
  62{
  63        struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
  64        struct inode *root_inode = d_inode(root->d_sb->s_root);
  65
  66        if (!sbi)
  67                return 0;
  68
  69        seq_printf(m, ",fd=%d", sbi->pipefd);
  70        if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  71                seq_printf(m, ",uid=%u",
  72                        from_kuid_munged(&init_user_ns, root_inode->i_uid));
  73        if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  74                seq_printf(m, ",gid=%u",
  75                        from_kgid_munged(&init_user_ns, root_inode->i_gid));
  76        seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  77        seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  78        seq_printf(m, ",minproto=%d", sbi->min_proto);
  79        seq_printf(m, ",maxproto=%d", sbi->max_proto);
  80
  81        if (autofs_type_offset(sbi->type))
  82                seq_puts(m, ",offset");
  83        else if (autofs_type_direct(sbi->type))
  84                seq_puts(m, ",direct");
  85        else
  86                seq_puts(m, ",indirect");
  87        if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
  88                seq_puts(m, ",strictexpire");
  89        if (sbi->flags & AUTOFS_SBI_IGNORE)
  90                seq_puts(m, ",ignore");
  91#ifdef CONFIG_CHECKPOINT_RESTORE
  92        if (sbi->pipe)
  93                seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
  94        else
  95                seq_puts(m, ",pipe_ino=-1");
  96#endif
  97        return 0;
  98}
  99
 100static void autofs_evict_inode(struct inode *inode)
 101{
 102        clear_inode(inode);
 103        kfree(inode->i_private);
 104}
 105
 106static const struct super_operations autofs_sops = {
 107        .statfs         = simple_statfs,
 108        .show_options   = autofs_show_options,
 109        .evict_inode    = autofs_evict_inode,
 110};
 111
 112enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 113        Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire,
 114        Opt_ignore};
 115
 116static const match_table_t tokens = {
 117        {Opt_fd, "fd=%u"},
 118        {Opt_uid, "uid=%u"},
 119        {Opt_gid, "gid=%u"},
 120        {Opt_pgrp, "pgrp=%u"},
 121        {Opt_minproto, "minproto=%u"},
 122        {Opt_maxproto, "maxproto=%u"},
 123        {Opt_indirect, "indirect"},
 124        {Opt_direct, "direct"},
 125        {Opt_offset, "offset"},
 126        {Opt_strictexpire, "strictexpire"},
 127        {Opt_ignore, "ignore"},
 128        {Opt_err, NULL}
 129};
 130
 131static int parse_options(char *options,
 132                         struct inode *root, int *pgrp, bool *pgrp_set,
 133                         struct autofs_sb_info *sbi)
 134{
 135        char *p;
 136        substring_t args[MAX_OPT_ARGS];
 137        int option;
 138        int pipefd = -1;
 139        kuid_t uid;
 140        kgid_t gid;
 141
 142        root->i_uid = current_uid();
 143        root->i_gid = current_gid();
 144
 145        sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
 146        sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
 147
 148        sbi->pipefd = -1;
 149
 150        if (!options)
 151                return 1;
 152
 153        while ((p = strsep(&options, ",")) != NULL) {
 154                int token;
 155
 156                if (!*p)
 157                        continue;
 158
 159                token = match_token(p, tokens, args);
 160                switch (token) {
 161                case Opt_fd:
 162                        if (match_int(args, &pipefd))
 163                                return 1;
 164                        sbi->pipefd = pipefd;
 165                        break;
 166                case Opt_uid:
 167                        if (match_int(args, &option))
 168                                return 1;
 169                        uid = make_kuid(current_user_ns(), option);
 170                        if (!uid_valid(uid))
 171                                return 1;
 172                        root->i_uid = uid;
 173                        break;
 174                case Opt_gid:
 175                        if (match_int(args, &option))
 176                                return 1;
 177                        gid = make_kgid(current_user_ns(), option);
 178                        if (!gid_valid(gid))
 179                                return 1;
 180                        root->i_gid = gid;
 181                        break;
 182                case Opt_pgrp:
 183                        if (match_int(args, &option))
 184                                return 1;
 185                        *pgrp = option;
 186                        *pgrp_set = true;
 187                        break;
 188                case Opt_minproto:
 189                        if (match_int(args, &option))
 190                                return 1;
 191                        sbi->min_proto = option;
 192                        break;
 193                case Opt_maxproto:
 194                        if (match_int(args, &option))
 195                                return 1;
 196                        sbi->max_proto = option;
 197                        break;
 198                case Opt_indirect:
 199                        set_autofs_type_indirect(&sbi->type);
 200                        break;
 201                case Opt_direct:
 202                        set_autofs_type_direct(&sbi->type);
 203                        break;
 204                case Opt_offset:
 205                        set_autofs_type_offset(&sbi->type);
 206                        break;
 207                case Opt_strictexpire:
 208                        sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
 209                        break;
 210                case Opt_ignore:
 211                        sbi->flags |= AUTOFS_SBI_IGNORE;
 212                        break;
 213                default:
 214                        return 1;
 215                }
 216        }
 217        return (sbi->pipefd < 0);
 218}
 219
 220int autofs_fill_super(struct super_block *s, void *data, int silent)
 221{
 222        struct inode *root_inode;
 223        struct dentry *root;
 224        struct file *pipe;
 225        struct autofs_sb_info *sbi;
 226        struct autofs_info *ino;
 227        int pgrp = 0;
 228        bool pgrp_set = false;
 229        int ret = -EINVAL;
 230
 231        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 232        if (!sbi)
 233                return -ENOMEM;
 234        pr_debug("starting up, sbi = %p\n", sbi);
 235
 236        s->s_fs_info = sbi;
 237        sbi->magic = AUTOFS_SBI_MAGIC;
 238        sbi->pipefd = -1;
 239        sbi->pipe = NULL;
 240        sbi->exp_timeout = 0;
 241        sbi->oz_pgrp = NULL;
 242        sbi->sb = s;
 243        sbi->version = 0;
 244        sbi->sub_version = 0;
 245        sbi->flags = AUTOFS_SBI_CATATONIC;
 246        set_autofs_type_indirect(&sbi->type);
 247        sbi->min_proto = 0;
 248        sbi->max_proto = 0;
 249        mutex_init(&sbi->wq_mutex);
 250        mutex_init(&sbi->pipe_mutex);
 251        spin_lock_init(&sbi->fs_lock);
 252        sbi->queues = NULL;
 253        spin_lock_init(&sbi->lookup_lock);
 254        INIT_LIST_HEAD(&sbi->active_list);
 255        INIT_LIST_HEAD(&sbi->expiring_list);
 256        s->s_blocksize = 1024;
 257        s->s_blocksize_bits = 10;
 258        s->s_magic = AUTOFS_SUPER_MAGIC;
 259        s->s_op = &autofs_sops;
 260        s->s_d_op = &autofs_dentry_operations;
 261        s->s_time_gran = 1;
 262
 263        /*
 264         * Get the root inode and dentry, but defer checking for errors.
 265         */
 266        ino = autofs_new_ino(sbi);
 267        if (!ino) {
 268                ret = -ENOMEM;
 269                goto fail_free;
 270        }
 271        root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 272        root = d_make_root(root_inode);
 273        if (!root) {
 274                ret = -ENOMEM;
 275                goto fail_ino;
 276        }
 277        pipe = NULL;
 278
 279        root->d_fsdata = ino;
 280
 281        /* Can this call block? */
 282        if (parse_options(data, root_inode, &pgrp, &pgrp_set, sbi)) {
 283                pr_err("called with bogus options\n");
 284                goto fail_dput;
 285        }
 286
 287        /* Test versions first */
 288        if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 289            sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 290                pr_err("kernel does not match daemon version "
 291                       "daemon (%d, %d) kernel (%d, %d)\n",
 292                       sbi->min_proto, sbi->max_proto,
 293                       AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 294                goto fail_dput;
 295        }
 296
 297        /* Establish highest kernel protocol version */
 298        if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 299                sbi->version = AUTOFS_MAX_PROTO_VERSION;
 300        else
 301                sbi->version = sbi->max_proto;
 302        sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 303
 304        if (pgrp_set) {
 305                sbi->oz_pgrp = find_get_pid(pgrp);
 306                if (!sbi->oz_pgrp) {
 307                        pr_err("could not find process group %d\n",
 308                                pgrp);
 309                        goto fail_dput;
 310                }
 311        } else {
 312                sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 313        }
 314
 315        if (autofs_type_trigger(sbi->type))
 316                __managed_dentry_set_managed(root);
 317
 318        root_inode->i_fop = &autofs_root_operations;
 319        root_inode->i_op = &autofs_dir_inode_operations;
 320
 321        pr_debug("pipe fd = %d, pgrp = %u\n",
 322                 sbi->pipefd, pid_nr(sbi->oz_pgrp));
 323        pipe = fget(sbi->pipefd);
 324
 325        if (!pipe) {
 326                pr_err("could not open pipe file descriptor\n");
 327                goto fail_put_pid;
 328        }
 329        ret = autofs_prepare_pipe(pipe);
 330        if (ret < 0)
 331                goto fail_fput;
 332        sbi->pipe = pipe;
 333        sbi->flags &= ~AUTOFS_SBI_CATATONIC;
 334
 335        /*
 336         * Success! Install the root dentry now to indicate completion.
 337         */
 338        s->s_root = root;
 339        return 0;
 340
 341        /*
 342         * Failure ... clean up.
 343         */
 344fail_fput:
 345        pr_err("pipe file descriptor does not contain proper ops\n");
 346        fput(pipe);
 347fail_put_pid:
 348        put_pid(sbi->oz_pgrp);
 349fail_dput:
 350        dput(root);
 351        goto fail_free;
 352fail_ino:
 353        autofs_free_ino(ino);
 354fail_free:
 355        kfree(sbi);
 356        s->s_fs_info = NULL;
 357        return ret;
 358}
 359
 360struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
 361{
 362        struct inode *inode = new_inode(sb);
 363
 364        if (inode == NULL)
 365                return NULL;
 366
 367        inode->i_mode = mode;
 368        if (sb->s_root) {
 369                inode->i_uid = d_inode(sb->s_root)->i_uid;
 370                inode->i_gid = d_inode(sb->s_root)->i_gid;
 371        }
 372        inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 373        inode->i_ino = get_next_ino();
 374
 375        if (S_ISDIR(mode)) {
 376                set_nlink(inode, 2);
 377                inode->i_op = &autofs_dir_inode_operations;
 378                inode->i_fop = &autofs_dir_operations;
 379        } else if (S_ISLNK(mode)) {
 380                inode->i_op = &autofs_symlink_inode_operations;
 381        } else
 382                WARN_ON(1);
 383
 384        return inode;
 385}
 386