1 files changed, 564 insertions, 0 deletions

diff --git a/fs/autofs/root.c b/fs/autofs/root.c
new file mode 100644
index 000000000000..a1ab1c0ed215
--- /dev/null
+++ b/fs/autofs/root.c
@@ -0,0 +1,564 @@
+/* -*- linux-c -*- --------------------------------------------------------- *
+ *
+ * linux/fs/autofs/root.c
+ *
+ *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * ------------------------------------------------------------------------- */
+
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/param.h>
+#include <linux/time.h>
+#include <linux/smp_lock.h>
+#include "autofs_i.h"
+
+static int autofs_root_readdir(struct file *,void *,filldir_t);
+static struct dentry *autofs_root_lookup(struct inode *,struct dentry *, struct nameidata *);
+static int autofs_root_symlink(struct inode *,struct dentry *,const char *);
+static int autofs_root_unlink(struct inode *,struct dentry *);
+static int autofs_root_rmdir(struct inode *,struct dentry *);
+static int autofs_root_mkdir(struct inode *,struct dentry *,int);
+static int autofs_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
+
+struct file_operations autofs_root_operations = {
+        .read           = generic_read_dir,
+        .readdir        = autofs_root_readdir,
+        .ioctl          = autofs_root_ioctl,
+};
+
+struct inode_operations autofs_root_inode_operations = {
+        .lookup         = autofs_root_lookup,
+        .unlink         = autofs_root_unlink,
+        .symlink        = autofs_root_symlink,
+        .mkdir          = autofs_root_mkdir,
+        .rmdir          = autofs_root_rmdir,
+};
+
+static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+        struct autofs_dir_ent *ent = NULL;
+        struct autofs_dirhash *dirhash;
+        struct autofs_sb_info *sbi;
+        struct inode * inode = filp->f_dentry->d_inode;
+        off_t onr, nr;
+
+        lock_kernel();
+
+        sbi = autofs_sbi(inode->i_sb);
+        dirhash = &sbi->dirhash;
+        nr = filp->f_pos;
+
+        switch(nr)
+        {
+        case 0:
+                if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
+                        goto out;
+                filp->f_pos = ++nr;
+                /* fall through */
+        case 1:
+                if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
+                        goto out;
+                filp->f_pos = ++nr;
+                /* fall through */
+        default:
+                while ( onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent) ) {
+                        if ( !ent->dentry || d_mountpoint(ent->dentry) ) {
+                                if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0)
+                                        goto out;
+                                filp->f_pos = nr;
+                        }
+                }
+                break;
+        }
+
+out:
+        unlock_kernel();
+        return 0;
+}
+
+static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi)
+{
+        struct inode * inode;
+        struct autofs_dir_ent *ent;
+        int status = 0;
+
+        if ( !(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) ) {
+                do {
+                        if ( status && dentry->d_inode ) {
+                                if ( status != -ENOENT )
+                                        printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name);
+                                return 0; /* Try to get the kernel to invalidate this dentry */
+                        }
+
+                        /* Turn this into a real negative dentry? */
+                        if (status == -ENOENT) {
+                                dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
+                                dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+                                return 1;
+                        } else if (status) {
+                                /* Return a negative dentry, but leave it "pending" */
+                                return 1;
+                        }
+                        status = autofs_wait(sbi, &dentry->d_name);
+                } while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)) );
+        }
+
+        /* Abuse this field as a pointer to the directory entry, used to
+           find the expire list pointers */
+        dentry->d_time = (unsigned long) ent;
+        
+        if (!dentry->d_inode) {
+                inode = iget(sb, ent->ino);
+                if (!inode) {
+                        /* Failed, but leave pending for next time */
+                        return 1;
+                }
+                dentry->d_inode = inode;
+        }
+
+        /* If this is a directory that isn't a mount point, bitch at the
+           daemon and fix it in user space */
+        if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
+                return !autofs_wait(sbi, &dentry->d_name);
+        }
+
+        /* We don't update the usages for the autofs daemon itself, this
+           is necessary for recursive autofs mounts */
+        if ( !autofs_oz_mode(sbi) ) {
+                autofs_update_usage(&sbi->dirhash,ent);
+        }
+
+        dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+        return 1;
+}
+
+
+/*
+ * Revalidate is called on every cache lookup.  Some of those
+ * cache lookups may actually happen while the dentry is not
+ * yet completely filled in, and revalidate has to delay such
+ * lookups..
+ */
+static int autofs_revalidate(struct dentry * dentry, struct nameidata *nd)
+{
+        struct inode * dir;
+        struct autofs_sb_info *sbi;
+        struct autofs_dir_ent *ent;
+        int res;
+
+        lock_kernel();
+        dir = dentry->d_parent->d_inode;
+        sbi = autofs_sbi(dir->i_sb);
+
+        /* Pending dentry */
+        if ( dentry->d_flags & DCACHE_AUTOFS_PENDING ) {
+                if (autofs_oz_mode(sbi))
+                        res = 1;
+                else
+                        res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
+                unlock_kernel();
+                return res;
+        }
+
+        /* Negative dentry.. invalidate if "old" */
+        if (!dentry->d_inode) {
+                unlock_kernel();
+                return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+        }
+                
+        /* Check for a non-mountpoint directory */
+        if ( S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) ) {
+                if (autofs_oz_mode(sbi))
+                        res = 1;
+                else
+                        res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
+                unlock_kernel();
+                return res;
+        }
+
+        /* Update the usage list */
+        if ( !autofs_oz_mode(sbi) ) {
+                ent = (struct autofs_dir_ent *) dentry->d_time;
+                if ( ent )
+                        autofs_update_usage(&sbi->dirhash,ent);
+        }
+        unlock_kernel();
+        return 1;
+}
+
+static struct dentry_operations autofs_dentry_operations = {
+        .d_revalidate   = autofs_revalidate,
+};
+
+static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+        struct autofs_sb_info *sbi;
+        int oz_mode;
+
+        DPRINTK(("autofs_root_lookup: name = "));
+        lock_kernel();
+        autofs_say(dentry->d_name.name,dentry->d_name.len);
+
+        if (dentry->d_name.len > NAME_MAX) {
+                unlock_kernel();
+                return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
+        }
+
+        sbi = autofs_sbi(dir->i_sb);
+
+        oz_mode = autofs_oz_mode(sbi);
+        DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
+                 current->pid, process_group(current), sbi->catatonic, oz_mode));
+
+        /*
+         * Mark the dentry incomplete, but add it. This is needed so
+         * that the VFS layer knows about the dentry, and we can count
+         * on catching any lookups through the revalidate.
+         *
+         * Let all the hard work be done by the revalidate function that
+         * needs to be able to do this anyway..
+         *
+         * We need to do this before we release the directory semaphore.
+         */
+        dentry->d_op = &autofs_dentry_operations;
+        dentry->d_flags |= DCACHE_AUTOFS_PENDING;
+        d_add(dentry, NULL);
+
+        up(&dir->i_sem);
+        autofs_revalidate(dentry, nd);
+        down(&dir->i_sem);
+
+        /*
+         * If we are still pending, check if we had to handle
+         * a signal. If so we can force a restart..
+         */
+        if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
+                /* See if we were interrupted */
+                if (signal_pending(current)) {
+                        sigset_t *sigset = &current->pending.signal;
+                        if (sigismember (sigset, SIGKILL) ||
+                            sigismember (sigset, SIGQUIT) ||
+                            sigismember (sigset, SIGINT)) {
+                                unlock_kernel();
+                                return ERR_PTR(-ERESTARTNOINTR);
+                        }
+                }
+        }
+        unlock_kernel();
+
+        /*
+         * If this dentry is unhashed, then we shouldn't honour this
+         * lookup even if the dentry is positive.  Returning ENOENT here
+         * doesn't do the right thing for all system calls, but it should
+         * be OK for the operations we permit from an autofs.
+         */
+        if ( dentry->d_inode && d_unhashed(dentry) )
+                return ERR_PTR(-ENOENT);
+
+        return NULL;
+}
+
+static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+        struct autofs_dirhash *dh = &sbi->dirhash;
+        struct autofs_dir_ent *ent;
+        unsigned int n;
+        int slsize;
+        struct autofs_symlink *sl;
+
+        DPRINTK(("autofs_root_symlink: %s <- ", symname));
+        autofs_say(dentry->d_name.name,dentry->d_name.len);
+
+        lock_kernel();
+        if ( !autofs_oz_mode(sbi) ) {
+                unlock_kernel();
+                return -EACCES;
+        }
+
+        if ( autofs_hash_lookup(dh, &dentry->d_name) ) {
+                unlock_kernel();
+                return -EEXIST;
+        }
+
+        n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
+        if ( n >= AUTOFS_MAX_SYMLINKS ) {
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        set_bit(n,sbi->symlink_bitmap);
+        sl = &sbi->symlink[n];
+        sl->len = strlen(symname);
+        sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL);
+        if ( !sl->data ) {
+                clear_bit(n,sbi->symlink_bitmap);
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
+        if ( !ent ) {
+                kfree(sl->data);
+                clear_bit(n,sbi->symlink_bitmap);
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
+        if ( !ent->name ) {
+                kfree(sl->data);
+                kfree(ent);
+                clear_bit(n,sbi->symlink_bitmap);
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        memcpy(sl->data,symname,slsize);
+        sl->mtime = get_seconds();
+
+        ent->ino = AUTOFS_FIRST_SYMLINK + n;
+        ent->hash = dentry->d_name.hash;
+        memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
+        ent->dentry = NULL;     /* We don't keep the dentry for symlinks */
+
+        autofs_hash_insert(dh,ent);
+        d_instantiate(dentry, iget(dir->i_sb,ent->ino));
+        unlock_kernel();
+        return 0;
+}
+
+/*
+ * NOTE!
+ *
+ * Normal filesystems would do a "d_delete()" to tell the VFS dcache
+ * that the file no longer exists. However, doing that means that the
+ * VFS layer can turn the dentry into a negative dentry, which we
+ * obviously do not want (we're dropping the entry not because it
+ * doesn't exist, but because it has timed out).
+ *
+ * Also see autofs_root_rmdir()..
+ */
+static int autofs_root_unlink(struct inode *dir, struct dentry *dentry)
+{
+        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+        struct autofs_dirhash *dh = &sbi->dirhash;
+        struct autofs_dir_ent *ent;
+        unsigned int n;
+
+        /* This allows root to remove symlinks */
+        lock_kernel();
+        if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) {
+                unlock_kernel();
+                return -EACCES;
+        }
+
+        ent = autofs_hash_lookup(dh, &dentry->d_name);
+        if ( !ent ) {
+                unlock_kernel();
+                return -ENOENT;
+        }
+
+        n = ent->ino - AUTOFS_FIRST_SYMLINK;
+        if ( n >= AUTOFS_MAX_SYMLINKS ) {
+                unlock_kernel();
+                return -EISDIR; /* It's a directory, dummy */
+        }
+        if ( !test_bit(n,sbi->symlink_bitmap) ) {
+                unlock_kernel();
+                return -EINVAL; /* Nonexistent symlink?  Shouldn't happen */
+        }
+        
+        dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL;
+        autofs_hash_delete(ent);
+        clear_bit(n,sbi->symlink_bitmap);
+        kfree(sbi->symlink[n].data);
+        d_drop(dentry);
+        
+        unlock_kernel();
+        return 0;
+}
+
+static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
+{
+        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+        struct autofs_dirhash *dh = &sbi->dirhash;
+        struct autofs_dir_ent *ent;
+
+        lock_kernel();
+        if ( !autofs_oz_mode(sbi) ) {
+                unlock_kernel();
+                return -EACCES;
+        }
+
+        ent = autofs_hash_lookup(dh, &dentry->d_name);
+        if ( !ent ) {
+                unlock_kernel();
+                return -ENOENT;
+        }
+
+        if ( (unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO ) {
+                unlock_kernel();
+                return -ENOTDIR; /* Not a directory */
+        }
+
+        if ( ent->dentry != dentry ) {
+                printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name);
+        }
+
+        dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL;
+        autofs_hash_delete(ent);
+        dir->i_nlink--;
+        d_drop(dentry);
+        unlock_kernel();
+
+        return 0;
+}
+
+static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+        struct autofs_dirhash *dh = &sbi->dirhash;
+        struct autofs_dir_ent *ent;
+        ino_t ino;
+
+        lock_kernel();
+        if ( !autofs_oz_mode(sbi) ) {
+                unlock_kernel();
+                return -EACCES;
+        }
+
+        ent = autofs_hash_lookup(dh, &dentry->d_name);
+        if ( ent ) {
+                unlock_kernel();
+                return -EEXIST;
+        }
+
+        if ( sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO ) {
+                printk("autofs: Out of inode numbers -- what the heck did you do??\n");
+                unlock_kernel();
+                return -ENOSPC;
+        }
+        ino = sbi->next_dir_ino++;
+
+        ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
+        if ( !ent ) {
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
+        if ( !ent->name ) {
+                kfree(ent);
+                unlock_kernel();
+                return -ENOSPC;
+        }
+
+        ent->hash = dentry->d_name.hash;
+        memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
+        ent->ino = ino;
+        ent->dentry = dentry;
+        autofs_hash_insert(dh,ent);
+
+        dir->i_nlink++;
+        d_instantiate(dentry, iget(dir->i_sb,ino));
+        unlock_kernel();
+
+        return 0;
+}
+
+/* Get/set timeout ioctl() operation */
+static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
+                                         unsigned long __user *p)
+{
+        unsigned long ntimeout;
+
+        if (get_user(ntimeout, p) ||
+            put_user(sbi->exp_timeout / HZ, p))
+                return -EFAULT;
+
+        if ( ntimeout > ULONG_MAX/HZ )
+                sbi->exp_timeout = 0;
+        else
+                sbi->exp_timeout = ntimeout * HZ;
+
+        return 0;
+}
+
+/* Return protocol version */
+static inline int autofs_get_protover(int __user *p)
+{
+        return put_user(AUTOFS_PROTO_VERSION, p);
+}
+
+/* Perform an expiry operation */
+static inline int autofs_expire_run(struct super_block *sb,
+                                    struct autofs_sb_info *sbi,
+                                    struct vfsmount *mnt,
+                                    struct autofs_packet_expire __user *pkt_p)
+{
+        struct autofs_dir_ent *ent;
+        struct autofs_packet_expire pkt;
+
+        memset(&pkt,0,sizeof pkt);
+
+        pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
+        pkt.hdr.type = autofs_ptype_expire;
+
+        if ( !sbi->exp_timeout ||
+             !(ent = autofs_expire(sb,sbi,mnt)) )
+                return -EAGAIN;
+
+        pkt.len = ent->len;
+        memcpy(pkt.name, ent->name, pkt.len);
+        pkt.name[pkt.len] = '\0';
+
+        if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
+                return -EFAULT;
+
+        return 0;
+}
+
+/*
+ * ioctl()'s on the root directory is the chief method for the daemon to
+ * generate kernel reactions
+ */
+static int autofs_root_ioctl(struct inode *inode, struct file *filp,
+                             unsigned int cmd, unsigned long arg)
+{
+        struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
+        void __user *argp = (void __user *)arg;
+
+        DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,process_group(current)));
+
+        if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
+             _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
+                return -ENOTTY;
+        
+        if ( !autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
+                return -EPERM;
+        
+        switch(cmd) {
+        case AUTOFS_IOC_READY:  /* Wait queue: go ahead and retry */
+                return autofs_wait_release(sbi,(autofs_wqt_t)arg,0);
+        case AUTOFS_IOC_FAIL:   /* Wait queue: fail with ENOENT */
+                return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
+        case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
+                autofs_catatonic_mode(sbi);
+                return 0;
+        case AUTOFS_IOC_PROTOVER: /* Get protocol version */
+                return autofs_get_protover(argp);
+        case AUTOFS_IOC_SETTIMEOUT:
+                return autofs_get_set_timeout(sbi, argp);
+        case AUTOFS_IOC_EXPIRE:
+                return autofs_expire_run(inode->i_sb, sbi, filp->f_vfsmnt,
+                                         argp);
+        default:
+                return -ENOSYS;
+        }
+}