/* -*- 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/capability.h> #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); const 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); mutex_unlock(&dir->i_mutex); autofs_revalidate(dentry, nd); mutex_lock(&dir->i_mutex); /* * 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 = ¤t->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; } }