aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/root.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/root.c')
-rw-r--r--kernel/root.c480
1 files changed, 480 insertions, 0 deletions
diff --git a/kernel/root.c b/kernel/root.c
new file mode 100644
index 0000000..919e61b
--- /dev/null
+++ b/kernel/root.c
@@ -0,0 +1,480 @@
+/* -*- linux-c -*- --------------------------------------------------------- *
+ *
+ * linux/fs/autofs/root.c
+ *
+ * Copyright 1997 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 "autofs_i.h"
+
+static int autofs_root_readdir(struct file *,void *,filldir_t);
+static int autofs_root_lookup(struct inode *,struct dentry *);
+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);
+
+static struct file_operations autofs_root_operations = {
+ NULL, /* llseek */
+ NULL, /* read */
+ NULL, /* write */
+ autofs_root_readdir, /* readdir */
+ NULL, /* poll */
+ autofs_root_ioctl, /* ioctl */
+ NULL, /* mmap */
+ NULL, /* open */
+ NULL, /* release */
+ NULL, /* fsync */
+ NULL, /* fasync */
+ NULL, /* check_media_change */
+ NULL, /* revalidate */
+ NULL /* lock */
+};
+
+struct inode_operations autofs_root_inode_operations = {
+ &autofs_root_operations, /* file operations */
+ NULL, /* create */
+ autofs_root_lookup, /* lookup */
+ NULL, /* link */
+ autofs_root_unlink, /* unlink */
+ autofs_root_symlink, /* symlink */
+ autofs_root_mkdir, /* mkdir */
+ autofs_root_rmdir, /* rmdir */
+ NULL, /* mknod */
+ NULL, /* rename */
+ NULL, /* readlink */
+ NULL, /* follow_link */
+ NULL, /* readpage */
+ NULL, /* writepage */
+ NULL, /* bmap */
+ NULL, /* truncate */
+ NULL, /* permission */
+ NULL, /* smap */
+ NULL, /* updatepage */
+ NULL /* revalidate */
+};
+
+static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+ struct autofs_dir_ent *ent;
+ struct autofs_dirhash *dirhash;
+ struct inode * inode = filp->f_dentry->d_inode;
+ off_t onr, nr;
+
+ if (!inode || !S_ISDIR(inode->i_mode))
+ return -ENOTDIR;
+
+ dirhash = &((struct autofs_sb_info *)inode->i_sb->u.generic_sbp)->dirhash;
+ nr = filp->f_pos;
+
+ switch(nr)
+ {
+ case 0:
+ if (filldir(dirent, ".", 1, nr, inode->i_ino) < 0)
+ return 0;
+ filp->f_pos = ++nr;
+ /* fall through */
+ case 1:
+ if (filldir(dirent, "..", 2, nr, inode->i_ino) < 0)
+ return 0;
+ filp->f_pos = ++nr;
+ /* fall through */
+ default:
+ while ( onr = nr, ent = autofs_hash_enum(dirhash,&nr) ) {
+ if (filldir(dirent,ent->name,ent->len,onr,ent->ino) < 0)
+ return 0;
+ filp->f_pos = nr;
+ }
+ break;
+ }
+
+ 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;
+
+ while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name))) {
+ int status = autofs_wait(sbi, &dentry->d_name);
+
+ /* 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;
+ }
+ }
+
+ /* 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 (S_ISDIR(dentry->d_inode->i_mode)) {
+ while (dentry == dentry->d_mounts)
+ schedule();
+ }
+
+ 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 autofs_sb_info *sbi;
+ struct inode * dir = dentry->d_parent->d_inode;
+ struct autofs_dir_ent *ent;
+
+ sbi = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+
+ /* Pending dentry */
+ if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
+ if (autofs_oz_mode(sbi))
+ return 1;
+
+ return try_to_fill_dentry(dentry, dir->i_sb, sbi);
+ }
+
+ /* Negative dentry.. invalidate if "old" */
+ if (!dentry->d_inode)
+ return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+
+ /* Update the usage list */
+ ent = (struct autofs_dir_ent *) dentry->d_time;
+ autofs_update_usage(&sbi->dirhash,ent);
+ return 1;
+}
+
+static struct dentry_operations autofs_dentry_operations = {
+ autofs_revalidate,
+ NULL, /* d_hash */
+ NULL, /* d_compare */
+};
+
+static int autofs_root_lookup(struct inode *dir, struct dentry * dentry)
+{
+ struct autofs_sb_info *sbi;
+ struct inode *res;
+ int oz_mode;
+
+ DPRINTK(("autofs_root_lookup: name = "));
+ autofs_say(dentry->d_name.name,dentry->d_name.len);
+
+ if (!S_ISDIR(dir->i_mode))
+ return -ENOTDIR;
+
+ res = NULL;
+ sbi = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+
+ oz_mode = autofs_oz_mode(sbi);
+ DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", current->pid, current->pgrp, 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);
+ 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) {
+ if (signal_pending(current))
+ return -ERESTARTNOINTR;
+ }
+
+ return 0;
+}
+
+static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+ struct autofs_sb_info *sbi = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+ 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);
+
+ if ( !autofs_oz_mode(sbi) )
+ return -EPERM;
+
+ if ( autofs_hash_lookup(dh, &dentry->d_name) )
+ return -EEXIST;
+
+ n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
+ if ( n >= AUTOFS_MAX_SYMLINKS )
+ 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);
+ return -ENOSPC;
+ }
+
+ ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
+ if ( !ent ) {
+ kfree(sl->data);
+ clear_bit(n,sbi->symlink_bitmap);
+ return -ENOSPC;
+ }
+
+ ent->name = kmalloc(dentry->d_name.len, GFP_KERNEL);
+ if ( !ent->name ) {
+ kfree(sl->data);
+ kfree(ent);
+ clear_bit(n,sbi->symlink_bitmap);
+ return -ENOSPC;
+ }
+
+ memcpy(sl->data,symname,slsize);
+ sl->mtime = CURRENT_TIME;
+
+ ent->ino = AUTOFS_FIRST_SYMLINK + n;
+ ent->hash = dentry->d_name.hash;
+ memcpy(ent->name, dentry->d_name.name,ent->len = dentry->d_name.len);
+
+ autofs_hash_insert(dh,ent);
+ d_instantiate(dentry, iget(dir->i_sb,ent->ino));
+
+ 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 = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+ struct autofs_dirhash *dh = &sbi->dirhash;
+ struct autofs_dir_ent *ent;
+ unsigned int n;
+
+ if ( !autofs_oz_mode(sbi) )
+ return -EPERM;
+
+ ent = autofs_hash_lookup(dh, &dentry->d_name);
+ if ( !ent )
+ return -ENOENT;
+
+ n = ent->ino - AUTOFS_FIRST_SYMLINK;
+ if ( n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap) )
+ return -EINVAL; /* Not a symlink inode, can't unlink */
+
+ autofs_hash_delete(ent);
+ clear_bit(n,sbi->symlink_bitmap);
+ kfree(sbi->symlink[n].data);
+ d_drop(dentry);
+
+ return 0;
+}
+
+static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct autofs_sb_info *sbi = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+ struct autofs_dirhash *dh = &sbi->dirhash;
+ struct autofs_dir_ent *ent;
+
+ if ( !autofs_oz_mode(sbi) )
+ return -EPERM;
+
+ ent = autofs_hash_lookup(dh, &dentry->d_name);
+ if ( !ent )
+ return -ENOENT;
+
+ if ( (unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO )
+ return -ENOTDIR; /* Not a directory */
+
+ autofs_hash_delete(ent);
+ dir->i_nlink--;
+ d_drop(dentry);
+
+ return 0;
+}
+
+static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ struct autofs_sb_info *sbi = (struct autofs_sb_info *) dir->i_sb->u.generic_sbp;
+ struct autofs_dirhash *dh = &sbi->dirhash;
+ struct autofs_dir_ent *ent;
+
+ if ( !autofs_oz_mode(sbi) )
+ return -EPERM;
+
+ ent = autofs_hash_lookup(dh, &dentry->d_name);
+ if ( ent )
+ return -EEXIST;
+
+ if ( sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO ) {
+ printk("autofs: Out of inode numbers -- what the heck did you do??\n");
+ return -ENOSPC;
+ }
+
+ ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
+ if ( !ent )
+ return -ENOSPC;
+
+ ent->name = kmalloc(dentry->d_name.len, GFP_KERNEL);
+ if ( !ent->name ) {
+ kfree(ent);
+ return -ENOSPC;
+ }
+
+ ent->hash = dentry->d_name.hash;
+ memcpy(ent->name, dentry->d_name.name, ent->len = dentry->d_name.len);
+ ent->ino = sbi->next_dir_ino++;
+ autofs_hash_insert(dh,ent);
+ dir->i_nlink++;
+ d_instantiate(dentry, iget(dir->i_sb,ent->ino));
+
+ return 0;
+}
+
+/* Get/set timeout ioctl() operation */
+static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
+ unsigned long *p)
+{
+ int rv;
+ unsigned long ntimeout;
+
+ if ( (rv = get_user(ntimeout, p)) ||
+ (rv = put_user(sbi->exp_timeout/HZ, p)) )
+ return rv;
+
+ 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 *p)
+{
+ return put_user(AUTOFS_PROTO_VERSION, p);
+}
+
+/* Perform an expiry operation */
+static inline int autofs_expire_run(struct autofs_sb_info *sbi,
+ struct autofs_packet_expire *pkt_p)
+{
+ struct autofs_dir_ent *ent;
+ struct autofs_packet_expire pkt;
+ struct autofs_dirhash *dh = &(sbi->dirhash);
+
+ 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(dh,sbi->exp_timeout)) )
+ 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;
+
+ autofs_update_usage(dh,ent);
+
+ 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 =
+ (struct autofs_sb_info *)inode->i_sb->u.generic_sbp;
+
+ DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,current->pgrp));
+
+ 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) && !fsuser() )
+ return -EPERM;
+
+ switch(cmd) {
+ case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
+ return autofs_wait_release(sbi,arg,0);
+ case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
+ return autofs_wait_release(sbi,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((int *)arg);
+ case AUTOFS_IOC_SETTIMEOUT:
+ return autofs_get_set_timeout(sbi,(unsigned long *)arg);
+ case AUTOFS_IOC_EXPIRE:
+ return autofs_expire_run(sbi,(struct autofs_packet_expire *)arg);
+ default:
+ return -ENOSYS;
+ }
+}
generated by cgit (git 2.34.1) at 2023-03-24 05:48:07 +0000