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+/* devfs (Device FileSystem) driver.
+
+ Copyright (C) 1998-2002 Richard Gooch
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with this library; if not, write to the Free
+ Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ Richard Gooch may be reached by email at rgooch@atnf.csiro.au
+ The postal address is:
+ Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia.
+
+ ChangeLog
+
+ 19980110 Richard Gooch <rgooch@atnf.csiro.au>
+ Original version.
+ v0.1
+ 19980111 Richard Gooch <rgooch@atnf.csiro.au>
+ Created per-fs inode table rather than using inode->u.generic_ip
+ v0.2
+ 19980111 Richard Gooch <rgooch@atnf.csiro.au>
+ Created .epoch inode which has a ctime of 0.
+ Fixed loss of named pipes when dentries lost.
+ Fixed loss of inode data when devfs_register() follows mknod().
+ v0.3
+ 19980111 Richard Gooch <rgooch@atnf.csiro.au>
+ Fix for when compiling with CONFIG_KERNELD.
+ 19980112 Richard Gooch <rgooch@atnf.csiro.au>
+ Fix for readdir() which sometimes didn't show entries.
+ Added <<tolerant>> option to <devfs_register>.
+ v0.4
+ 19980113 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_fill_file> function.
+ v0.5
+ 19980115 Richard Gooch <rgooch@atnf.csiro.au>
+ Added subdirectory support. Major restructuring.
+ 19980116 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed <find_by_dev> to not search major=0,minor=0.
+ Added symlink support.
+ v0.6
+ 19980120 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_mk_dir> function and support directory unregister
+ 19980120 Richard Gooch <rgooch@atnf.csiro.au>
+ Auto-ownership uses real uid/gid rather than effective uid/gid.
+ v0.7
+ 19980121 Richard Gooch <rgooch@atnf.csiro.au>
+ Supported creation of sockets.
+ v0.8
+ 19980122 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFS_FL_HIDE_UNREG flag.
+ Interface change to <devfs_mk_symlink>.
+ Created <devfs_symlink> to support symlink(2).
+ v0.9
+ 19980123 Richard Gooch <rgooch@atnf.csiro.au>
+ Added check to <devfs_fill_file> to check inode is in devfs.
+ Added optional traversal of symlinks.
+ v0.10
+ 19980124 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_flags> and <devfs_set_flags>.
+ v0.11
+ 19980125 C. Scott Ananian <cananian@alumni.princeton.edu>
+ Created <devfs_find_handle>.
+ 19980125 Richard Gooch <rgooch@atnf.csiro.au>
+ Allow removal of symlinks.
+ v0.12
+ 19980125 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_set_symlink_destination>.
+ 19980126 Richard Gooch <rgooch@atnf.csiro.au>
+ Moved DEVFS_SUPER_MAGIC into header file.
+ Added DEVFS_FL_HIDE flag.
+ Created <devfs_get_maj_min>.
+ Created <devfs_get_handle_from_inode>.
+ Fixed minor bug in <find_by_dev>.
+ 19980127 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed interface to <find_by_dev>, <find_entry>,
+ <devfs_unregister>, <devfs_fill_file> and <devfs_find_handle>.
+ Fixed inode times when symlink created with symlink(2).
+ v0.13
+ 19980129 C. Scott Ananian <cananian@alumni.princeton.edu>
+ Exported <devfs_set_symlink_destination>, <devfs_get_maj_min>
+ and <devfs_get_handle_from_inode>.
+ 19980129 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_unlink> to support unlink(2).
+ v0.14
+ 19980129 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed kerneld support for entries in devfs subdirectories.
+ 19980130 Richard Gooch <rgooch@atnf.csiro.au>
+ Bugfixes in <call_kerneld>.
+ v0.15
+ 19980207 Richard Gooch <rgooch@atnf.csiro.au>
+ Call kerneld when looking up unregistered entries.
+ v0.16
+ 19980326 Richard Gooch <rgooch@atnf.csiro.au>
+ Modified interface to <devfs_find_handle> for symlink traversal.
+ v0.17
+ 19980331 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed persistence bug with device numbers for manually created
+ device files.
+ Fixed problem with recreating symlinks with different content.
+ v0.18
+ 19980401 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed to CONFIG_KMOD.
+ Hide entries which are manually unlinked.
+ Always invalidate devfs dentry cache when registering entries.
+ Created <devfs_rmdir> to support rmdir(2).
+ Ensure directories created by <devfs_mk_dir> are visible.
+ v0.19
+ 19980402 Richard Gooch <rgooch@atnf.csiro.au>
+ Invalidate devfs dentry cache when making directories.
+ Invalidate devfs dentry cache when removing entries.
+ Fixed persistence bug with fifos.
+ v0.20
+ 19980421 Richard Gooch <rgooch@atnf.csiro.au>
+ Print process command when debugging kerneld/kmod.
+ Added debugging for register/unregister/change operations.
+ 19980422 Richard Gooch <rgooch@atnf.csiro.au>
+ Added "devfs=" boot options.
+ v0.21
+ 19980426 Richard Gooch <rgooch@atnf.csiro.au>
+ No longer lock/unlock superblock in <devfs_put_super>.
+ Drop negative dentries when they are released.
+ Manage dcache more efficiently.
+ v0.22
+ 19980427 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFS_FL_AUTO_DEVNUM flag.
+ v0.23
+ 19980430 Richard Gooch <rgooch@atnf.csiro.au>
+ No longer set unnecessary methods.
+ v0.24
+ 19980504 Richard Gooch <rgooch@atnf.csiro.au>
+ Added PID display to <call_kerneld> debugging message.
+ Added "after" debugging message to <call_kerneld>.
+ 19980519 Richard Gooch <rgooch@atnf.csiro.au>
+ Added "diread" and "diwrite" boot options.
+ 19980520 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed persistence problem with permissions.
+ v0.25
+ 19980602 Richard Gooch <rgooch@atnf.csiro.au>
+ Support legacy device nodes.
+ Fixed bug where recreated inodes were hidden.
+ v0.26
+ 19980602 Richard Gooch <rgooch@atnf.csiro.au>
+ Improved debugging in <get_vfs_inode>.
+ 19980607 Richard Gooch <rgooch@atnf.csiro.au>
+ No longer free old dentries in <devfs_mk_dir>.
+ Free all dentries for a given entry when deleting inodes.
+ v0.27
+ 19980627 Richard Gooch <rgooch@atnf.csiro.au>
+ Limit auto-device numbering to majors 128 to 239.
+ v0.28
+ 19980629 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed inode times persistence problem.
+ v0.29
+ 19980704 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed spelling in <devfs_readlink> debug.
+ Fixed bug in <devfs_setup> parsing "dilookup".
+ v0.30
+ 19980705 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed devfs inode leak when manually recreating inodes.
+ Fixed permission persistence problem when recreating inodes.
+ v0.31
+ 19980727 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed harmless "unused variable" compiler warning.
+ Fixed modes for manually recreated device nodes.
+ v0.32
+ 19980728 Richard Gooch <rgooch@atnf.csiro.au>
+ Added NULL devfs inode warning in <devfs_read_inode>.
+ Force all inode nlink values to 1.
+ v0.33
+ 19980730 Richard Gooch <rgooch@atnf.csiro.au>
+ Added "dimknod" boot option.
+ Set inode nlink to 0 when freeing dentries.
+ Fixed modes for manually recreated symlinks.
+ v0.34
+ 19980802 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bugs in recreated directories and symlinks.
+ v0.35
+ 19980806 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bugs in recreated device nodes.
+ 19980807 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bug in currently unused <devfs_get_handle_from_inode>.
+ Defined new <devfs_handle_t> type.
+ Improved debugging when getting entries.
+ Fixed bug where directories could be emptied.
+ v0.36
+ 19980809 Richard Gooch <rgooch@atnf.csiro.au>
+ Replaced dummy .epoch inode with .devfsd character device.
+ 19980810 Richard Gooch <rgooch@atnf.csiro.au>
+ Implemented devfsd protocol revision 0.
+ v0.37
+ 19980819 Richard Gooch <rgooch@atnf.csiro.au>
+ Added soothing message to warning in <devfs_d_iput>.
+ v0.38
+ 19980829 Richard Gooch <rgooch@atnf.csiro.au>
+ Use GCC extensions for structure initialisations.
+ Implemented async open notification.
+ Incremented devfsd protocol revision to 1.
+ v0.39
+ 19980908 Richard Gooch <rgooch@atnf.csiro.au>
+ Moved async open notification to end of <devfs_open>.
+ v0.40
+ 19980910 Richard Gooch <rgooch@atnf.csiro.au>
+ Prepended "/dev/" to module load request.
+ Renamed <call_kerneld> to <call_kmod>.
+ v0.41
+ 19980910 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed typo "AYSNC" -> "ASYNC".
+ v0.42
+ 19980910 Richard Gooch <rgooch@atnf.csiro.au>
+ Added open flag for files.
+ v0.43
+ 19980927 Richard Gooch <rgooch@atnf.csiro.au>
+ Set i_blocks=0 and i_blksize=1024 in <devfs_read_inode>.
+ v0.44
+ 19981005 Richard Gooch <rgooch@atnf.csiro.au>
+ Added test for empty <<name>> in <devfs_find_handle>.
+ Renamed <generate_path> to <devfs_generate_path> and published.
+ v0.45
+ 19981006 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_fops>.
+ v0.46
+ 19981007 Richard Gooch <rgooch@atnf.csiro.au>
+ Limit auto-device numbering to majors 144 to 239.
+ v0.47
+ 19981010 Richard Gooch <rgooch@atnf.csiro.au>
+ Updated <devfs_follow_link> for VFS change in 2.1.125.
+ v0.48
+ 19981022 Richard Gooch <rgooch@atnf.csiro.au>
+ Created DEVFS_ FL_COMPAT flag.
+ v0.49
+ 19981023 Richard Gooch <rgooch@atnf.csiro.au>
+ Created "nocompat" boot option.
+ v0.50
+ 19981025 Richard Gooch <rgooch@atnf.csiro.au>
+ Replaced "mount" boot option with "nomount".
+ v0.51
+ 19981110 Richard Gooch <rgooch@atnf.csiro.au>
+ Created "only" boot option.
+ v0.52
+ 19981112 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFS_FL_REMOVABLE flag.
+ v0.53
+ 19981114 Richard Gooch <rgooch@atnf.csiro.au>
+ Only call <scan_dir_for_removable> on first call to
+ <devfs_readdir>.
+ v0.54
+ 19981205 Richard Gooch <rgooch@atnf.csiro.au>
+ Updated <devfs_rmdir> for VFS change in 2.1.131.
+ v0.55
+ 19981218 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_mk_compat>.
+ 19981220 Richard Gooch <rgooch@atnf.csiro.au>
+ Check for partitions on removable media in <devfs_lookup>.
+ v0.56
+ 19990118 Richard Gooch <rgooch@atnf.csiro.au>
+ Added support for registering regular files.
+ Created <devfs_set_file_size>.
+ Update devfs inodes from entries if not changed through FS.
+ v0.57
+ 19990124 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed <devfs_fill_file> to only initialise temporary inodes.
+ Trap for NULL fops in <devfs_register>.
+ Return -ENODEV in <devfs_fill_file> for non-driver inodes.
+ v0.58
+ 19990126 Richard Gooch <rgooch@atnf.csiro.au>
+ Switched from PATH_MAX to DEVFS_PATHLEN.
+ v0.59
+ 19990127 Richard Gooch <rgooch@atnf.csiro.au>
+ Created "nottycompat" boot option.
+ v0.60
+ 19990318 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed <devfsd_read> to not overrun event buffer.
+ v0.61
+ 19990329 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_auto_unregister>.
+ v0.62
+ 19990330 Richard Gooch <rgooch@atnf.csiro.au>
+ Don't return unregistred entries in <devfs_find_handle>.
+ Panic in <devfs_unregister> if entry unregistered.
+ 19990401 Richard Gooch <rgooch@atnf.csiro.au>
+ Don't panic in <devfs_auto_unregister> for duplicates.
+ v0.63
+ 19990402 Richard Gooch <rgooch@atnf.csiro.au>
+ Don't unregister already unregistered entries in <unregister>.
+ v0.64
+ 19990510 Richard Gooch <rgooch@atnf.csiro.au>
+ Disable warning messages when unable to read partition table for
+ removable media.
+ v0.65
+ 19990512 Richard Gooch <rgooch@atnf.csiro.au>
+ Updated <devfs_lookup> for VFS change in 2.3.1-pre1.
+ Created "oops-on-panic" boot option.
+ Improved debugging in <devfs_register> and <devfs_unregister>.
+ v0.66
+ 19990519 Richard Gooch <rgooch@atnf.csiro.au>
+ Added documentation for some functions.
+ 19990525 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed "oops-on-panic" boot option: now always Oops.
+ v0.67
+ 19990531 Richard Gooch <rgooch@atnf.csiro.au>
+ Improved debugging in <devfs_register>.
+ v0.68
+ 19990604 Richard Gooch <rgooch@atnf.csiro.au>
+ Added "diunlink" and "nokmod" boot options.
+ Removed superfluous warning message in <devfs_d_iput>.
+ v0.69
+ 19990611 Richard Gooch <rgooch@atnf.csiro.au>
+ Took account of change to <d_alloc_root>.
+ v0.70
+ 19990614 Richard Gooch <rgooch@atnf.csiro.au>
+ Created separate event queue for each mounted devfs.
+ Removed <devfs_invalidate_dcache>.
+ Created new ioctl()s.
+ Incremented devfsd protocol revision to 3.
+ Fixed bug when re-creating directories: contents were lost.
+ Block access to inodes until devfsd updates permissions.
+ 19990615 Richard Gooch <rgooch@atnf.csiro.au>
+ Support 2.2.x kernels.
+ v0.71
+ 19990623 Richard Gooch <rgooch@atnf.csiro.au>
+ Switched to sending process uid/gid to devfsd.
+ Renamed <call_kmod> to <try_modload>.
+ Added DEVFSD_NOTIFY_LOOKUP event.
+ 19990624 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFSD_NOTIFY_CHANGE event.
+ Incremented devfsd protocol revision to 4.
+ v0.72
+ 19990713 Richard Gooch <rgooch@atnf.csiro.au>
+ Return EISDIR rather than EINVAL for read(2) on directories.
+ v0.73
+ 19990809 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed <devfs_setup> to new __init scheme.
+ v0.74
+ 19990901 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed remaining function declarations to new __init scheme.
+ v0.75
+ 19991013 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_info>, <devfs_set_info>,
+ <devfs_get_first_child> and <devfs_get_next_sibling>.
+ Added <<dir>> parameter to <devfs_register>, <devfs_mk_compat>,
+ <devfs_mk_dir> and <devfs_find_handle>.
+ Work sponsored by SGI.
+ v0.76
+ 19991017 Richard Gooch <rgooch@atnf.csiro.au>
+ Allow multiple unregistrations.
+ Work sponsored by SGI.
+ v0.77
+ 19991026 Richard Gooch <rgooch@atnf.csiro.au>
+ Added major and minor number to devfsd protocol.
+ Incremented devfsd protocol revision to 5.
+ Work sponsored by SGI.
+ v0.78
+ 19991030 Richard Gooch <rgooch@atnf.csiro.au>
+ Support info pointer for all devfs entry types.
+ Added <<info>> parameter to <devfs_mk_dir> and
+ <devfs_mk_symlink>.
+ Work sponsored by SGI.
+ v0.79
+ 19991031 Richard Gooch <rgooch@atnf.csiro.au>
+ Support "../" when searching devfs namespace.
+ Work sponsored by SGI.
+ v0.80
+ 19991101 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_unregister_slave>.
+ Work sponsored by SGI.
+ v0.81
+ 19991103 Richard Gooch <rgooch@atnf.csiro.au>
+ Exported <devfs_get_parent>.
+ Work sponsored by SGI.
+ v0.82
+ 19991104 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed unused <devfs_set_symlink_destination>.
+ 19991105 Richard Gooch <rgooch@atnf.csiro.au>
+ Do not hide entries from devfsd or children.
+ Removed DEVFS_ FL_TTY_COMPAT flag.
+ Removed "nottycompat" boot option.
+ Removed <devfs_mk_compat>.
+ Work sponsored by SGI.
+ v0.83
+ 19991107 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFS_FL_WAIT flag.
+ Work sponsored by SGI.
+ v0.84
+ 19991107 Richard Gooch <rgooch@atnf.csiro.au>
+ Support new "disc" naming scheme in <get_removable_partition>.
+ Allow NULL fops in <devfs_register>.
+ Work sponsored by SGI.
+ v0.85
+ 19991110 Richard Gooch <rgooch@atnf.csiro.au>
+ Fall back to major table if NULL fops given to <devfs_register>.
+ Work sponsored by SGI.
+ v0.86
+ 19991204 Richard Gooch <rgooch@atnf.csiro.au>
+ Support fifos when unregistering.
+ Work sponsored by SGI.
+ v0.87
+ 19991209 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed obsolete DEVFS_ FL_COMPAT and DEVFS_ FL_TOLERANT flags.
+ Work sponsored by SGI.
+ v0.88
+ 19991214 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed kmod support.
+ Work sponsored by SGI.
+ v0.89
+ 19991216 Richard Gooch <rgooch@atnf.csiro.au>
+ Improved debugging in <get_vfs_inode>.
+ Ensure dentries created by devfsd will be cleaned up.
+ Work sponsored by SGI.
+ v0.90
+ 19991223 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_name>.
+ Work sponsored by SGI.
+ v0.91
+ 20000203 Richard Gooch <rgooch@atnf.csiro.au>
+ Ported to kernel 2.3.42.
+ Removed <devfs_fill_file>.
+ Work sponsored by SGI.
+ v0.92
+ 20000306 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFS_ FL_NO_PERSISTENCE flag.
+ Removed unnecessary call to <update_devfs_inode_from_entry> in
+ <devfs_readdir>.
+ Work sponsored by SGI.
+ v0.93
+ 20000413 Richard Gooch <rgooch@atnf.csiro.au>
+ Set inode->i_size to correct size for symlinks.
+ 20000414 Richard Gooch <rgooch@atnf.csiro.au>
+ Only give lookup() method to directories to comply with new VFS
+ assumptions.
+ Work sponsored by SGI.
+ 20000415 Richard Gooch <rgooch@atnf.csiro.au>
+ Remove unnecessary tests in symlink methods.
+ Don't kill existing block ops in <devfs_read_inode>.
+ Work sponsored by SGI.
+ v0.94
+ 20000424 Richard Gooch <rgooch@atnf.csiro.au>
+ Don't create missing directories in <devfs_find_handle>.
+ Work sponsored by SGI.
+ v0.95
+ 20000430 Richard Gooch <rgooch@atnf.csiro.au>
+ Added CONFIG_DEVFS_MOUNT.
+ Work sponsored by SGI.
+ v0.96
+ 20000608 Richard Gooch <rgooch@atnf.csiro.au>
+ Disabled multi-mount capability (use VFS bindings instead).
+ Work sponsored by SGI.
+ v0.97
+ 20000610 Richard Gooch <rgooch@atnf.csiro.au>
+ Switched to FS_SINGLE to disable multi-mounts.
+ 20000612 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed module support.
+ Removed multi-mount code.
+ Removed compatibility macros: VFS has changed too much.
+ Work sponsored by SGI.
+ v0.98
+ 20000614 Richard Gooch <rgooch@atnf.csiro.au>
+ Merged devfs inode into devfs entry.
+ Work sponsored by SGI.
+ v0.99
+ 20000619 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed dead code in <devfs_register> which used to call
+ <free_dentries>.
+ Work sponsored by SGI.
+ v0.100
+ 20000621 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed interface to <devfs_register>.
+ Work sponsored by SGI.
+ v0.101
+ 20000622 Richard Gooch <rgooch@atnf.csiro.au>
+ Simplified interface to <devfs_mk_symlink> and <devfs_mk_dir>.
+ Simplified interface to <devfs_find_handle>.
+ Work sponsored by SGI.
+ v0.102
+ 20010519 Richard Gooch <rgooch@atnf.csiro.au>
+ Ensure <devfs_generate_path> terminates string for root entry.
+ Exported <devfs_get_name> to modules.
+ 20010520 Richard Gooch <rgooch@atnf.csiro.au>
+ Make <devfs_mk_symlink> send events to devfsd.
+ Cleaned up option processing in <devfs_setup>.
+ 20010521 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bugs in handling symlinks: could leak or cause Oops.
+ 20010522 Richard Gooch <rgooch@atnf.csiro.au>
+ Cleaned up directory handling by separating fops.
+ v0.103
+ 20010601 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed handling of inverted options in <devfs_setup>.
+ v0.104
+ 20010604 Richard Gooch <rgooch@atnf.csiro.au>
+ Adjusted <try_modload> to account for <devfs_generate_path> fix.
+ v0.105
+ 20010617 Richard Gooch <rgooch@atnf.csiro.au>
+ Answered question posed by Al Viro and removed his comments.
+ Moved setting of registered flag after other fields are changed.
+ Fixed race between <devfsd_close> and <devfsd_notify_one>.
+ Global VFS changes added bogus BKL to <devfsd_close>: removed.
+ Widened locking in <devfs_readlink> and <devfs_follow_link>.
+ Replaced <devfsd_read> stack usage with <devfsd_ioctl> kmalloc.
+ Simplified locking in <devfsd_ioctl> and fixed memory leak.
+ v0.106
+ 20010709 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed broken devnum allocation and use <devfs_alloc_devnum>.
+ Fixed old devnum leak by calling new <devfs_dealloc_devnum>.
+ v0.107
+ 20010712 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bug in <devfs_setup> which could hang boot process.
+ v0.108
+ 20010730 Richard Gooch <rgooch@atnf.csiro.au>
+ Added DEVFSD_NOTIFY_DELETE event.
+ 20010801 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed #include <asm/segment.h>.
+ v0.109
+ 20010807 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed inode table races by removing it and using
+ inode->u.generic_ip instead.
+ Moved <devfs_read_inode> into <get_vfs_inode>.
+ Moved <devfs_write_inode> into <devfs_notify_change>.
+ v0.110
+ 20010808 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed race in <devfs_do_symlink> for uni-processor.
+ v0.111
+ 20010818 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed remnant of multi-mount support in <devfs_mknod>.
+ Removed unused DEVFS_FL_SHOW_UNREG flag.
+ v0.112
+ 20010820 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed nlink field from struct devfs_inode.
+ v0.113
+ 20010823 Richard Gooch <rgooch@atnf.csiro.au>
+ Replaced BKL with global rwsem to protect symlink data (quick
+ and dirty hack).
+ v0.114
+ 20010827 Richard Gooch <rgooch@atnf.csiro.au>
+ Replaced global rwsem for symlink with per-link refcount.
+ v0.115
+ 20010919 Richard Gooch <rgooch@atnf.csiro.au>
+ Set inode->i_mapping->a_ops for block nodes in <get_vfs_inode>.
+ v0.116
+ 20011008 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed overrun in <devfs_link> by removing function (not needed).
+ 20011009 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed buffer underrun in <try_modload>.
+ 20011029 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed race in <devfsd_ioctl> when setting event mask.
+ 20011114 Richard Gooch <rgooch@atnf.csiro.au>
+ First release of new locking code.
+ v1.0
+ 20011117 Richard Gooch <rgooch@atnf.csiro.au>
+ Discard temporary buffer, now use "%s" for dentry names.
+ 20011118 Richard Gooch <rgooch@atnf.csiro.au>
+ Don't generate path in <try_modload>: use fake entry instead.
+ Use "existing" directory in <_devfs_make_parent_for_leaf>.
+ 20011122 Richard Gooch <rgooch@atnf.csiro.au>
+ Use slab cache rather than fixed buffer for devfsd events.
+ v1.1
+ 20011125 Richard Gooch <rgooch@atnf.csiro.au>
+ Send DEVFSD_NOTIFY_REGISTERED events in <devfs_mk_dir>.
+ 20011127 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed locking bug in <devfs_d_revalidate_wait> due to typo.
+ Do not send CREATE, CHANGE, ASYNC_OPEN or DELETE events from
+ devfsd or children.
+ v1.2
+ 20011202 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bug in <devfsd_read>: was dereferencing freed pointer.
+ v1.3
+ 20011203 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed bug in <devfsd_close>: was dereferencing freed pointer.
+ Added process group check for devfsd privileges.
+ v1.4
+ 20011204 Richard Gooch <rgooch@atnf.csiro.au>
+ Use SLAB_ATOMIC in <devfsd_notify_de> from <devfs_d_delete>.
+ v1.5
+ 20011211 Richard Gooch <rgooch@atnf.csiro.au>
+ Return old entry in <devfs_mk_dir> for 2.4.x kernels.
+ 20011212 Richard Gooch <rgooch@atnf.csiro.au>
+ Increment refcount on module in <check_disc_changed>.
+ 20011215 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_get_handle> and exported <devfs_put>.
+ Increment refcount on module in <devfs_get_ops>.
+ Created <devfs_put_ops>.
+ v1.6
+ 20011216 Richard Gooch <rgooch@atnf.csiro.au>
+ Added poisoning to <devfs_put>.
+ Improved debugging messages.
+ v1.7
+ 20011221 Richard Gooch <rgooch@atnf.csiro.au>
+ Corrected (made useful) debugging message in <unregister>.
+ Moved <kmem_cache_create> in <mount_devfs_fs> to <init_devfs_fs>
+ 20011224 Richard Gooch <rgooch@atnf.csiro.au>
+ Added magic number to guard against scribbling drivers.
+ 20011226 Richard Gooch <rgooch@atnf.csiro.au>
+ Only return old entry in <devfs_mk_dir> if a directory.
+ Defined macros for error and debug messages.
+ v1.8
+ 20020113 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed (rare, old) race in <devfs_lookup>.
+ v1.9
+ 20020120 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed deadlock bug in <devfs_d_revalidate_wait>.
+ Tag VFS deletable in <devfs_mk_symlink> if handle ignored.
+ v1.10
+ 20020129 Richard Gooch <rgooch@atnf.csiro.au>
+ Added KERN_* to remaining messages.
+ Cleaned up declaration of <stat_read>.
+ v1.11
+ 20020219 Richard Gooch <rgooch@atnf.csiro.au>
+ Changed <devfs_rmdir> to allow later additions if not yet empty.
+ v1.12
+ 20020406 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed silently introduced calls to lock_kernel() and
+ unlock_kernel() due to recent VFS locking changes. BKL isn't
+ required in devfs.
+ v1.13
+ 20020428 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed 2.4.x compatibility code.
+ v1.14
+ 20020510 Richard Gooch <rgooch@atnf.csiro.au>
+ Added BKL to <devfs_open> because drivers still need it.
+ v1.15
+ 20020512 Richard Gooch <rgooch@atnf.csiro.au>
+ Protected <scan_dir_for_removable> and <get_removable_partition>
+ from changing directory contents.
+ v1.16
+ 20020514 Richard Gooch <rgooch@atnf.csiro.au>
+ Minor cleanup of <scan_dir_for_removable>.
+ v1.17
+ 20020721 Richard Gooch <rgooch@atnf.csiro.au>
+ Switched to ISO C structure field initialisers.
+ Switch to set_current_state() and move before add_wait_queue().
+ 20020722 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed devfs entry leak in <devfs_readdir> when *readdir fails.
+ v1.18
+ 20020725 Richard Gooch <rgooch@atnf.csiro.au>
+ Created <devfs_find_and_unregister>.
+ v1.19
+ 20020728 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed deprecated <devfs_find_handle>.
+ v1.20
+ 20020820 Richard Gooch <rgooch@atnf.csiro.au>
+ Fixed module unload race in <devfs_open>.
+ v1.21
+ 20021013 Richard Gooch <rgooch@atnf.csiro.au>
+ Removed DEVFS_ FL_AUTO_OWNER.
+ Switched lingering structure field initialiser to ISO C.
+ Added locking when updating FCB flags.
+ v1.22
+*/
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/tty.h>
+#include <linux/timer.h>
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/wait.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/devfs_fs.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/smp_lock.h>
+#include <linux/smp.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/namei.h>
+#include <linux/bitops.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/atomic.h>
+
+#define DEVFS_VERSION "2004-01-31"
+
+#define DEVFS_NAME "devfs"
+
+#define FIRST_INODE 1
+
+#define STRING_LENGTH 256
+#define FAKE_BLOCK_SIZE 1024
+#define POISON_PTR ( *(void **) poison_array )
+#define MAGIC_VALUE 0x327db823
+
+#ifndef TRUE
+# define TRUE 1
+# define FALSE 0
+#endif
+
+#define MODE_DIR (S_IFDIR | S_IWUSR | S_IRUGO | S_IXUGO)
+
+#define DEBUG_NONE 0x0000000
+#define DEBUG_MODULE_LOAD 0x0000001
+#define DEBUG_REGISTER 0x0000002
+#define DEBUG_UNREGISTER 0x0000004
+#define DEBUG_FREE 0x0000008
+#define DEBUG_SET_FLAGS 0x0000010
+#define DEBUG_S_READ 0x0000100 /* Break */
+#define DEBUG_I_LOOKUP 0x0001000 /* Break */
+#define DEBUG_I_CREATE 0x0002000
+#define DEBUG_I_GET 0x0004000
+#define DEBUG_I_CHANGE 0x0008000
+#define DEBUG_I_UNLINK 0x0010000
+#define DEBUG_I_RLINK 0x0020000
+#define DEBUG_I_FLINK 0x0040000
+#define DEBUG_I_MKNOD 0x0080000
+#define DEBUG_F_READDIR 0x0100000 /* Break */
+#define DEBUG_D_DELETE 0x1000000 /* Break */
+#define DEBUG_D_RELEASE 0x2000000
+#define DEBUG_D_IPUT 0x4000000
+#define DEBUG_ALL 0xfffffff
+#define DEBUG_DISABLED DEBUG_NONE
+
+#define OPTION_NONE 0x00
+#define OPTION_MOUNT 0x01
+
+#define PRINTK(format, args...) \
+ {printk (KERN_ERR "%s" format, __FUNCTION__ , ## args);}
+
+#define OOPS(format, args...) \
+ {printk (KERN_CRIT "%s" format, __FUNCTION__ , ## args); \
+ printk ("Forcing Oops\n"); \
+ BUG();}
+
+#ifdef CONFIG_DEVFS_DEBUG
+# define VERIFY_ENTRY(de) \
+ {if ((de) && (de)->magic_number != MAGIC_VALUE) \
+ OOPS ("(%p): bad magic value: %x\n", (de), (de)->magic_number);}
+# define WRITE_ENTRY_MAGIC(de,magic) (de)->magic_number = (magic)
+# define DPRINTK(flag, format, args...) \
+ {if (devfs_debug & flag) \
+ printk (KERN_INFO "%s" format, __FUNCTION__ , ## args);}
+#else
+# define VERIFY_ENTRY(de)
+# define WRITE_ENTRY_MAGIC(de,magic)
+# define DPRINTK(flag, format, args...)
+#endif
+
+typedef struct devfs_entry *devfs_handle_t;
+
+struct directory_type {
+ rwlock_t lock; /* Lock for searching(R)/updating(W) */
+ struct devfs_entry *first;
+ struct devfs_entry *last;
+ unsigned char no_more_additions:1;
+};
+
+struct symlink_type {
+ unsigned int length; /* Not including the NULL-termimator */
+ char *linkname; /* This is NULL-terminated */
+};
+
+struct devfs_inode { /* This structure is for "persistent" inode storage */
+ struct dentry *dentry;
+ struct timespec atime;
+ struct timespec mtime;
+ struct timespec ctime;
+ unsigned int ino; /* Inode number as seen in the VFS */
+ uid_t uid;
+ gid_t gid;
+};
+
+struct devfs_entry {
+#ifdef CONFIG_DEVFS_DEBUG
+ unsigned int magic_number;
+#endif
+ void *info;
+ atomic_t refcount; /* When this drops to zero, it's unused */
+ union {
+ struct directory_type dir;
+ dev_t dev;
+ struct symlink_type symlink;
+ const char *name; /* Only used for (mode == 0) */
+ } u;
+ struct devfs_entry *prev; /* Previous entry in the parent directory */
+ struct devfs_entry *next; /* Next entry in the parent directory */
+ struct devfs_entry *parent; /* The parent directory */
+ struct devfs_inode inode;
+ umode_t mode;
+ unsigned short namelen; /* I think 64k+ filenames are a way off... */
+ unsigned char vfs:1; /* Whether the VFS may delete the entry */
+ char name[1]; /* This is just a dummy: the allocated array
+ is bigger. This is NULL-terminated */
+};
+
+/* The root of the device tree */
+static struct devfs_entry *root_entry;
+
+struct devfsd_buf_entry {
+ struct devfs_entry *de; /* The name is generated with this */
+ unsigned short type; /* The type of event */
+ umode_t mode;
+ uid_t uid;
+ gid_t gid;
+ struct devfsd_buf_entry *next;
+};
+
+struct fs_info { /* This structure is for the mounted devfs */
+ struct super_block *sb;
+ spinlock_t devfsd_buffer_lock; /* Lock when inserting/deleting events */
+ struct devfsd_buf_entry *devfsd_first_event;
+ struct devfsd_buf_entry *devfsd_last_event;
+ volatile int devfsd_sleeping;
+ volatile struct task_struct *devfsd_task;
+ volatile pid_t devfsd_pgrp;
+ volatile struct file *devfsd_file;
+ struct devfsd_notify_struct *devfsd_info;
+ volatile unsigned long devfsd_event_mask;
+ atomic_t devfsd_overrun_count;
+ wait_queue_head_t devfsd_wait_queue; /* Wake devfsd on input */
+ wait_queue_head_t revalidate_wait_queue; /* Wake when devfsd sleeps */
+};
+
+static struct fs_info fs_info = {.devfsd_buffer_lock = SPIN_LOCK_UNLOCKED };
+static kmem_cache_t *devfsd_buf_cache;
+#ifdef CONFIG_DEVFS_DEBUG
+static unsigned int devfs_debug_init __initdata = DEBUG_NONE;
+static unsigned int devfs_debug = DEBUG_NONE;
+static DEFINE_SPINLOCK(stat_lock);
+static unsigned int stat_num_entries;
+static unsigned int stat_num_bytes;
+#endif
+static unsigned char poison_array[8] =
+ { 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a };
+
+#ifdef CONFIG_DEVFS_MOUNT
+static unsigned int boot_options = OPTION_MOUNT;
+#else
+static unsigned int boot_options = OPTION_NONE;
+#endif
+
+/* Forward function declarations */
+static devfs_handle_t _devfs_walk_path(struct devfs_entry *dir,
+ const char *name, int namelen,
+ int traverse_symlink);
+static ssize_t devfsd_read(struct file *file, char __user *buf, size_t len,
+ loff_t * ppos);
+static int devfsd_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg);
+static int devfsd_close(struct inode *inode, struct file *file);
+#ifdef CONFIG_DEVFS_DEBUG
+static ssize_t stat_read(struct file *file, char __user *buf, size_t len,
+ loff_t * ppos);
+static struct file_operations stat_fops = {
+ .open = nonseekable_open,
+ .read = stat_read,
+};
+#endif
+
+/* Devfs daemon file operations */
+static struct file_operations devfsd_fops = {
+ .open = nonseekable_open,
+ .read = devfsd_read,
+ .ioctl = devfsd_ioctl,
+ .release = devfsd_close,
+};
+
+/* Support functions follow */
+
+/**
+ * devfs_get - Get a reference to a devfs entry.
+ * @de: The devfs entry.
+ */
+
+static struct devfs_entry *devfs_get(struct devfs_entry *de)
+{
+ VERIFY_ENTRY(de);
+ if (de)
+ atomic_inc(&de->refcount);
+ return de;
+} /* End Function devfs_get */
+
+/**
+ * devfs_put - Put (release) a reference to a devfs entry.
+ * @de: The handle to the devfs entry.
+ */
+
+static void devfs_put(devfs_handle_t de)
+{
+ if (!de)
+ return;
+ VERIFY_ENTRY(de);
+ if (de->info == POISON_PTR)
+ OOPS("(%p): poisoned pointer\n", de);
+ if (!atomic_dec_and_test(&de->refcount))
+ return;
+ if (de == root_entry)
+ OOPS("(%p): root entry being freed\n", de);
+ DPRINTK(DEBUG_FREE, "(%s): de: %p, parent: %p \"%s\"\n",
+ de->name, de, de->parent,
+ de->parent ? de->parent->name : "no parent");
+ if (S_ISLNK(de->mode))
+ kfree(de->u.symlink.linkname);
+ WRITE_ENTRY_MAGIC(de, 0);
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock(&stat_lock);
+ --stat_num_entries;
+ stat_num_bytes -= sizeof *de + de->namelen;
+ if (S_ISLNK(de->mode))
+ stat_num_bytes -= de->u.symlink.length + 1;
+ spin_unlock(&stat_lock);
+#endif
+ de->info = POISON_PTR;
+ kfree(de);
+} /* End Function devfs_put */
+
+/**
+ * _devfs_search_dir - Search for a devfs entry in a directory.
+ * @dir: The directory to search.
+ * @name: The name of the entry to search for.
+ * @namelen: The number of characters in @name.
+ *
+ * Search for a devfs entry in a directory and returns a pointer to the entry
+ * on success, else %NULL. The directory must be locked already.
+ * An implicit devfs_get() is performed on the returned entry.
+ */
+
+static struct devfs_entry *_devfs_search_dir(struct devfs_entry *dir,
+ const char *name,
+ unsigned int namelen)
+{
+ struct devfs_entry *curr;
+
+ if (!S_ISDIR(dir->mode)) {
+ PRINTK("(%s): not a directory\n", dir->name);
+ return NULL;
+ }
+ for (curr = dir->u.dir.first; curr != NULL; curr = curr->next) {
+ if (curr->namelen != namelen)
+ continue;
+ if (memcmp(curr->name, name, namelen) == 0)
+ break;
+ /* Not found: try the next one */
+ }
+ return devfs_get(curr);
+} /* End Function _devfs_search_dir */
+
+/**
+ * _devfs_alloc_entry - Allocate a devfs entry.
+ * @name: the name of the entry
+ * @namelen: the number of characters in @name
+ * @mode: the mode for the entry
+ *
+ * Allocate a devfs entry and returns a pointer to the entry on success, else
+ * %NULL.
+ */
+
+static struct devfs_entry *_devfs_alloc_entry(const char *name,
+ unsigned int namelen,
+ umode_t mode)
+{
+ struct devfs_entry *new;
+ static unsigned long inode_counter = FIRST_INODE;
+ static DEFINE_SPINLOCK(counter_lock);
+
+ if (name && (namelen < 1))
+ namelen = strlen(name);
+ if ((new = kmalloc(sizeof *new + namelen, GFP_KERNEL)) == NULL)
+ return NULL;
+ memset(new, 0, sizeof *new + namelen); /* Will set '\0' on name */
+ new->mode = mode;
+ if (S_ISDIR(mode))
+ rwlock_init(&new->u.dir.lock);
+ atomic_set(&new->refcount, 1);
+ spin_lock(&counter_lock);
+ new->inode.ino = inode_counter++;
+ spin_unlock(&counter_lock);
+ if (name)
+ memcpy(new->name, name, namelen);
+ new->namelen = namelen;
+ WRITE_ENTRY_MAGIC(new, MAGIC_VALUE);
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock(&stat_lock);
+ ++stat_num_entries;
+ stat_num_bytes += sizeof *new + namelen;
+ spin_unlock(&stat_lock);
+#endif
+ return new;
+} /* End Function _devfs_alloc_entry */
+
+/**
+ * _devfs_append_entry - Append a devfs entry to a directory's child list.
+ * @dir: The directory to add to.
+ * @de: The devfs entry to append.
+ * @old_de: If an existing entry exists, it will be written here. This may
+ * be %NULL. An implicit devfs_get() is performed on this entry.
+ *
+ * Append a devfs entry to a directory's list of children, checking first to
+ * see if an entry of the same name exists. The directory will be locked.
+ * The value 0 is returned on success, else a negative error code.
+ * On failure, an implicit devfs_put() is performed on %de.
+ */
+
+static int _devfs_append_entry(devfs_handle_t dir, devfs_handle_t de,
+ devfs_handle_t * old_de)
+{
+ int retval;
+
+ if (old_de)
+ *old_de = NULL;
+ if (!S_ISDIR(dir->mode)) {
+ PRINTK("(%s): dir: \"%s\" is not a directory\n", de->name,
+ dir->name);
+ devfs_put(de);
+ return -ENOTDIR;
+ }
+ write_lock(&dir->u.dir.lock);
+ if (dir->u.dir.no_more_additions)
+ retval = -ENOENT;
+ else {
+ struct devfs_entry *old;
+
+ old = _devfs_search_dir(dir, de->name, de->namelen);
+ if (old_de)
+ *old_de = old;
+ else
+ devfs_put(old);
+ if (old == NULL) {
+ de->parent = dir;
+ de->prev = dir->u.dir.last;
+ /* Append to the directory's list of children */
+ if (dir->u.dir.first == NULL)
+ dir->u.dir.first = de;
+ else
+ dir->u.dir.last->next = de;
+ dir->u.dir.last = de;
+ retval = 0;
+ } else
+ retval = -EEXIST;
+ }
+ write_unlock(&dir->u.dir.lock);
+ if (retval)
+ devfs_put(de);
+ return retval;
+} /* End Function _devfs_append_entry */
+
+/**
+ * _devfs_get_root_entry - Get the root devfs entry.
+ *
+ * Returns the root devfs entry on success, else %NULL.
+ *
+ * TODO it must be called asynchronously due to the fact
+ * that devfs is initialized relatively late. Proper way
+ * is to remove module_init from init_devfs_fs and manually
+ * call it early enough during system init
+ */
+
+static struct devfs_entry *_devfs_get_root_entry(void)
+{
+ struct devfs_entry *new;
+ static DEFINE_SPINLOCK(root_lock);
+
+ if (root_entry)
+ return root_entry;
+
+ new = _devfs_alloc_entry(NULL, 0, MODE_DIR);
+ if (new == NULL)
+ return NULL;
+
+ spin_lock(&root_lock);
+ if (root_entry) {
+ spin_unlock(&root_lock);
+ devfs_put(new);
+ return root_entry;
+ }
+ root_entry = new;
+ spin_unlock(&root_lock);
+
+ return root_entry;
+} /* End Function _devfs_get_root_entry */
+
+/**
+ * _devfs_descend - Descend down a tree using the next component name.
+ * @dir: The directory to search.
+ * @name: The component name to search for.
+ * @namelen: The length of %name.
+ * @next_pos: The position of the next '/' or '\0' is written here.
+ *
+ * Descend into a directory, searching for a component. This function forms
+ * the core of a tree-walking algorithm. The directory will be locked.
+ * The devfs entry corresponding to the component is returned. If there is
+ * no matching entry, %NULL is returned.
+ * An implicit devfs_get() is performed on the returned entry.
+ */
+
+static struct devfs_entry *_devfs_descend(struct devfs_entry *dir,
+ const char *name, int namelen,
+ int *next_pos)
+{
+ const char *stop, *ptr;
+ struct devfs_entry *entry;
+
+ if ((namelen >= 3) && (strncmp(name, "../", 3) == 0)) { /* Special-case going to parent directory */
+ *next_pos = 3;
+ return devfs_get(dir->parent);
+ }
+ stop = name + namelen;
+ /* Search for a possible '/' */
+ for (ptr = name; (ptr < stop) && (*ptr != '/'); ++ptr) ;
+ *next_pos = ptr - name;
+ read_lock(&dir->u.dir.lock);
+ entry = _devfs_search_dir(dir, name, *next_pos);
+ read_unlock(&dir->u.dir.lock);
+ return entry;
+} /* End Function _devfs_descend */
+
+static devfs_handle_t _devfs_make_parent_for_leaf(struct devfs_entry *dir,
+ const char *name,
+ int namelen, int *leaf_pos)
+{
+ int next_pos = 0;
+
+ if (dir == NULL)
+ dir = _devfs_get_root_entry();
+ if (dir == NULL)
+ return NULL;
+ devfs_get(dir);
+ /* Search for possible trailing component and ignore it */
+ for (--namelen; (namelen > 0) && (name[namelen] != '/'); --namelen) ;
+ *leaf_pos = (name[namelen] == '/') ? (namelen + 1) : 0;
+ for (; namelen > 0; name += next_pos, namelen -= next_pos) {
+ struct devfs_entry *de, *old = NULL;
+
+ if ((de =
+ _devfs_descend(dir, name, namelen, &next_pos)) == NULL) {
+ de = _devfs_alloc_entry(name, next_pos, MODE_DIR);
+ devfs_get(de);
+ if (!de || _devfs_append_entry(dir, de, &old)) {
+ devfs_put(de);
+ if (!old || !S_ISDIR(old->mode)) {
+ devfs_put(old);
+ devfs_put(dir);
+ return NULL;
+ }
+ de = old; /* Use the existing directory */
+ }
+ }
+ if (de == dir->parent) {
+ devfs_put(dir);
+ devfs_put(de);
+ return NULL;
+ }
+ devfs_put(dir);
+ dir = de;
+ if (name[next_pos] == '/')
+ ++next_pos;
+ }
+ return dir;
+} /* End Function _devfs_make_parent_for_leaf */
+
+static devfs_handle_t _devfs_prepare_leaf(devfs_handle_t * dir,
+ const char *name, umode_t mode)
+{
+ int namelen, leaf_pos;
+ struct devfs_entry *de;
+
+ namelen = strlen(name);
+ if ((*dir = _devfs_make_parent_for_leaf(*dir, name, namelen,
+ &leaf_pos)) == NULL) {
+ PRINTK("(%s): could not create parent path\n", name);
+ return NULL;
+ }
+ if ((de = _devfs_alloc_entry(name + leaf_pos, namelen - leaf_pos, mode))
+ == NULL) {
+ PRINTK("(%s): could not allocate entry\n", name);
+ devfs_put(*dir);
+ return NULL;
+ }
+ return de;
+} /* End Function _devfs_prepare_leaf */
+
+static devfs_handle_t _devfs_walk_path(struct devfs_entry *dir,
+ const char *name, int namelen,
+ int traverse_symlink)
+{
+ int next_pos = 0;
+
+ if (dir == NULL)
+ dir = _devfs_get_root_entry();
+ if (dir == NULL)
+ return NULL;
+ devfs_get(dir);
+ for (; namelen > 0; name += next_pos, namelen -= next_pos) {
+ struct devfs_entry *de, *link;
+
+ if (!S_ISDIR(dir->mode)) {
+ devfs_put(dir);
+ return NULL;
+ }
+
+ if ((de =
+ _devfs_descend(dir, name, namelen, &next_pos)) == NULL) {
+ devfs_put(dir);
+ return NULL;
+ }
+ if (S_ISLNK(de->mode) && traverse_symlink) { /* Need to follow the link: this is a stack chomper */
+ /* FIXME what if it puts outside of mounted tree? */
+ link = _devfs_walk_path(dir, de->u.symlink.linkname,
+ de->u.symlink.length, TRUE);
+ devfs_put(de);
+ if (!link) {
+ devfs_put(dir);
+ return NULL;
+ }
+ de = link;
+ }
+ devfs_put(dir);
+ dir = de;
+ if (name[next_pos] == '/')
+ ++next_pos;
+ }
+ return dir;
+} /* End Function _devfs_walk_path */
+
+/**
+ * _devfs_find_entry - Find a devfs entry.
+ * @dir: The handle to the parent devfs directory entry. If this is %NULL the
+ * name is relative to the root of the devfs.
+ * @name: The name of the entry. This may be %NULL.
+ * @traverse_symlink: If %TRUE then symbolic links are traversed.
+ *
+ * Returns the devfs_entry pointer on success, else %NULL. An implicit
+ * devfs_get() is performed.
+ */
+
+static struct devfs_entry *_devfs_find_entry(devfs_handle_t dir,
+ const char *name,
+ int traverse_symlink)
+{
+ unsigned int namelen = strlen(name);
+
+ if (name[0] == '/') {
+ /* Skip leading pathname component */
+ if (namelen < 2) {
+ PRINTK("(%s): too short\n", name);
+ return NULL;
+ }
+ for (++name, --namelen; (*name != '/') && (namelen > 0);
+ ++name, --namelen) ;
+ if (namelen < 2) {
+ PRINTK("(%s): too short\n", name);
+ return NULL;
+ }
+ ++name;
+ --namelen;
+ }
+ return _devfs_walk_path(dir, name, namelen, traverse_symlink);
+} /* End Function _devfs_find_entry */
+
+static struct devfs_entry *get_devfs_entry_from_vfs_inode(struct inode *inode)
+{
+ if (inode == NULL)
+ return NULL;
+ VERIFY_ENTRY((struct devfs_entry *)inode->u.generic_ip);
+ return inode->u.generic_ip;
+} /* End Function get_devfs_entry_from_vfs_inode */
+
+/**
+ * free_dentry - Free the dentry for a device entry and invalidate inode.
+ * @de: The entry.
+ *
+ * This must only be called after the entry has been unhooked from its
+ * parent directory.
+ */
+
+static void free_dentry(struct devfs_entry *de)
+{
+ struct dentry *dentry = de->inode.dentry;
+
+ if (!dentry)
+ return;
+ spin_lock(&dcache_lock);
+ dget_locked(dentry);
+ spin_unlock(&dcache_lock);
+ /* Forcefully remove the inode */
+ if (dentry->d_inode != NULL)
+ dentry->d_inode->i_nlink = 0;
+ d_drop(dentry);
+ dput(dentry);
+} /* End Function free_dentry */
+
+/**
+ * is_devfsd_or_child - Test if the current process is devfsd or one of its children.
+ * @fs_info: The filesystem information.
+ *
+ * Returns %TRUE if devfsd or child, else %FALSE.
+ */
+
+static int is_devfsd_or_child(struct fs_info *fs_info)
+{
+ struct task_struct *p = current;
+
+ if (p == fs_info->devfsd_task)
+ return (TRUE);
+ if (process_group(p) == fs_info->devfsd_pgrp)
+ return (TRUE);
+ read_lock(&tasklist_lock);
+ for (; p != &init_task; p = p->real_parent) {
+ if (p == fs_info->devfsd_task) {
+ read_unlock(&tasklist_lock);
+ return (TRUE);
+ }
+ }
+ read_unlock(&tasklist_lock);
+ return (FALSE);
+} /* End Function is_devfsd_or_child */
+
+/**
+ * devfsd_queue_empty - Test if devfsd has work pending in its event queue.
+ * @fs_info: The filesystem information.
+ *
+ * Returns %TRUE if the queue is empty, else %FALSE.
+ */
+
+static inline int devfsd_queue_empty(struct fs_info *fs_info)
+{
+ return (fs_info->devfsd_last_event) ? FALSE : TRUE;
+} /* End Function devfsd_queue_empty */
+
+/**
+ * wait_for_devfsd_finished - Wait for devfsd to finish processing its event queue.
+ * @fs_info: The filesystem information.
+ *
+ * Returns %TRUE if no more waiting will be required, else %FALSE.
+ */
+
+static int wait_for_devfsd_finished(struct fs_info *fs_info)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ if (fs_info->devfsd_task == NULL)
+ return (TRUE);
+ if (devfsd_queue_empty(fs_info) && fs_info->devfsd_sleeping)
+ return TRUE;
+ if (is_devfsd_or_child(fs_info))
+ return (FALSE);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&fs_info->revalidate_wait_queue, &wait);
+ if (!devfsd_queue_empty(fs_info) || !fs_info->devfsd_sleeping)
+ if (fs_info->devfsd_task)
+ schedule();
+ remove_wait_queue(&fs_info->revalidate_wait_queue, &wait);
+ __set_current_state(TASK_RUNNING);
+ return (TRUE);
+} /* End Function wait_for_devfsd_finished */
+
+/**
+ * devfsd_notify_de - Notify the devfsd daemon of a change.
+ * @de: The devfs entry that has changed. This and all parent entries will
+ * have their reference counts incremented if the event was queued.
+ * @type: The type of change.
+ * @mode: The mode of the entry.
+ * @uid: The user ID.
+ * @gid: The group ID.
+ * @fs_info: The filesystem info.
+ *
+ * Returns %TRUE if an event was queued and devfsd woken up, else %FALSE.
+ */
+
+static int devfsd_notify_de(struct devfs_entry *de,
+ unsigned short type, umode_t mode,
+ uid_t uid, gid_t gid, struct fs_info *fs_info)
+{
+ struct devfsd_buf_entry *entry;
+ struct devfs_entry *curr;
+
+ if (!(fs_info->devfsd_event_mask & (1 << type)))
+ return (FALSE);
+ if ((entry = kmem_cache_alloc(devfsd_buf_cache, SLAB_KERNEL)) == NULL) {
+ atomic_inc(&fs_info->devfsd_overrun_count);
+ return (FALSE);
+ }
+ for (curr = de; curr != NULL; curr = curr->parent)
+ devfs_get(curr);
+ entry->de = de;
+ entry->type = type;
+ entry->mode = mode;
+ entry->uid = uid;
+ entry->gid = gid;
+ entry->next = NULL;
+ spin_lock(&fs_info->devfsd_buffer_lock);
+ if (!fs_info->devfsd_first_event)
+ fs_info->devfsd_first_event = entry;
+ if (fs_info->devfsd_last_event)
+ fs_info->devfsd_last_event->next = entry;
+ fs_info->devfsd_last_event = entry;
+ spin_unlock(&fs_info->devfsd_buffer_lock);
+ wake_up_interruptible(&fs_info->devfsd_wait_queue);
+ return (TRUE);
+} /* End Function devfsd_notify_de */
+
+/**
+ * devfsd_notify - Notify the devfsd daemon of a change.
+ * @de: The devfs entry that has changed.
+ * @type: The type of change event.
+ * @wait: If TRUE, the function waits for the daemon to finish processing
+ * the event.
+ */
+
+static void devfsd_notify(struct devfs_entry *de, unsigned short type)
+{
+ devfsd_notify_de(de, type, de->mode, current->euid,
+ current->egid, &fs_info);
+}
+
+static int devfs_mk_dev(dev_t dev, umode_t mode, const char *fmt, va_list args)
+{
+ struct devfs_entry *dir = NULL, *de;
+ char buf[64];
+ int error, n;
+
+ n = vsnprintf(buf, sizeof(buf), fmt, args);
+ if (n >= sizeof(buf) || !buf[0]) {
+ printk(KERN_WARNING "%s: invalid format string %s\n",
+ __FUNCTION__, fmt);
+ return -EINVAL;
+ }
+
+ de = _devfs_prepare_leaf(&dir, buf, mode);
+ if (!de) {
+ printk(KERN_WARNING "%s: could not prepare leaf for %s\n",
+ __FUNCTION__, buf);
+ return -ENOMEM; /* could be more accurate... */
+ }
+
+ de->u.dev = dev;
+
+ error = _devfs_append_entry(dir, de, NULL);
+ if (error) {
+ printk(KERN_WARNING "%s: could not append to parent for %s\n",
+ __FUNCTION__, buf);
+ goto out;
+ }
+
+ devfsd_notify(de, DEVFSD_NOTIFY_REGISTERED);
+ out:
+ devfs_put(dir);
+ return error;
+}
+
+int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+{
+ va_list args;
+
+ if (!S_ISBLK(mode)) {
+ printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+ __FUNCTION__, mode, fmt);
+ return -EINVAL;
+ }
+
+ va_start(args, fmt);
+ return devfs_mk_dev(dev, mode, fmt, args);
+}
+
+EXPORT_SYMBOL(devfs_mk_bdev);
+
+int devfs_mk_cdev(dev_t dev, umode_t mode, const char *fmt, ...)
+{
+ va_list args;
+
+ if (!S_ISCHR(mode)) {
+ printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+ __FUNCTION__, mode, fmt);
+ return -EINVAL;
+ }
+
+ va_start(args, fmt);
+ return devfs_mk_dev(dev, mode, fmt, args);
+}
+
+EXPORT_SYMBOL(devfs_mk_cdev);
+
+/**
+ * _devfs_unhook - Unhook a device entry from its parents list
+ * @de: The entry to unhook.
+ *
+ * Returns %TRUE if the entry was unhooked, else %FALSE if it was
+ * previously unhooked.
+ * The caller must have a write lock on the parent directory.
+ */
+
+static int _devfs_unhook(struct devfs_entry *de)
+{
+ struct devfs_entry *parent;
+
+ if (!de || (de->prev == de))
+ return FALSE;
+ parent = de->parent;
+ if (de->prev == NULL)
+ parent->u.dir.first = de->next;
+ else
+ de->prev->next = de->next;
+ if (de->next == NULL)
+ parent->u.dir.last = de->prev;
+ else
+ de->next->prev = de->prev;
+ de->prev = de; /* Indicate we're unhooked */
+ de->next = NULL; /* Force early termination for <devfs_readdir> */
+ return TRUE;
+} /* End Function _devfs_unhook */
+
+/**
+ * _devfs_unregister - Unregister a device entry from its parent.
+ * @dir: The parent directory.
+ * @de: The entry to unregister.
+ *
+ * The caller must have a write lock on the parent directory, which is
+ * unlocked by this function.
+ */
+
+static void _devfs_unregister(struct devfs_entry *dir, struct devfs_entry *de)
+{
+ int unhooked = _devfs_unhook(de);
+
+ write_unlock(&dir->u.dir.lock);
+ if (!unhooked)
+ return;
+ devfs_get(dir);
+ devfsd_notify(de, DEVFSD_NOTIFY_UNREGISTERED);
+ free_dentry(de);
+ devfs_put(dir);
+ if (!S_ISDIR(de->mode))
+ return;
+ while (TRUE) { /* Recursively unregister: this is a stack chomper */
+ struct devfs_entry *child;
+
+ write_lock(&de->u.dir.lock);
+ de->u.dir.no_more_additions = TRUE;
+ child = de->u.dir.first;
+ VERIFY_ENTRY(child);
+ _devfs_unregister(de, child);
+ if (!child)
+ break;
+ DPRINTK(DEBUG_UNREGISTER, "(%s): child: %p refcount: %d\n",
+ child->name, child, atomic_read(&child->refcount));
+ devfs_put(child);
+ }
+} /* End Function _devfs_unregister */
+
+static int devfs_do_symlink(devfs_handle_t dir, const char *name,
+ const char *link, devfs_handle_t * handle)
+{
+ int err;
+ unsigned int linklength;
+ char *newlink;
+ struct devfs_entry *de;
+
+ if (handle != NULL)
+ *handle = NULL;
+ if (name == NULL) {
+ PRINTK("(): NULL name pointer\n");
+ return -EINVAL;
+ }
+ if (link == NULL) {
+ PRINTK("(%s): NULL link pointer\n", name);
+ return -EINVAL;
+ }
+ linklength = strlen(link);
+ if ((newlink = kmalloc(linklength + 1, GFP_KERNEL)) == NULL)
+ return -ENOMEM;
+ memcpy(newlink, link, linklength);
+ newlink[linklength] = '\0';
+ if ((de = _devfs_prepare_leaf(&dir, name, S_IFLNK | S_IRUGO | S_IXUGO))
+ == NULL) {
+ PRINTK("(%s): could not prepare leaf\n", name);
+ kfree(newlink);
+ return -ENOTDIR;
+ }
+ de->info = NULL;
+ de->u.symlink.linkname = newlink;
+ de->u.symlink.length = linklength;
+ if ((err = _devfs_append_entry(dir, de, NULL)) != 0) {
+ PRINTK("(%s): could not append to parent, err: %d\n", name,
+ err);
+ devfs_put(dir);
+ return err;
+ }
+ devfs_put(dir);
+#ifdef CONFIG_DEVFS_DEBUG
+ spin_lock(&stat_lock);
+ stat_num_bytes += linklength + 1;
+ spin_unlock(&stat_lock);
+#endif
+ if (handle != NULL)
+ *handle = de;
+ return 0;
+} /* End Function devfs_do_symlink */
+
+/**
+ * devfs_mk_symlink Create a symbolic link in the devfs namespace.
+ * @from: The name of the entry.
+ * @to: Name of the destination
+ *
+ * Returns 0 on success, else a negative error code is returned.
+ */
+
+int devfs_mk_symlink(const char *from, const char *to)
+{
+ devfs_handle_t de;
+ int err;
+
+ err = devfs_do_symlink(NULL, from, to, &de);
+ if (!err) {
+ de->vfs = TRUE;
+ devfsd_notify(de, DEVFSD_NOTIFY_REGISTERED);
+ }
+
+ return err;
+}
+
+/**
+ * devfs_mk_dir - Create a directory in the devfs namespace.
+ * new name is relative to the root of the devfs.
+ * @fmt: The name of the entry.
+ *
+ * Use of this function is optional. The devfs_register() function
+ * will automatically create intermediate directories as needed. This function
+ * is provided for efficiency reasons, as it provides a handle to a directory.
+ * On failure %NULL is returned.
+ */
+
+int devfs_mk_dir(const char *fmt, ...)
+{
+ struct devfs_entry *dir = NULL, *de = NULL, *old;
+ char buf[64];
+ va_list args;
+ int error, n;
+
+ va_start(args, fmt);
+ n = vsnprintf(buf, 64, fmt, args);
+ if (n >= 64 || !buf[0]) {
+ printk(KERN_WARNING "%s: invalid argument.", __FUNCTION__);
+ return -EINVAL;
+ }
+
+ de = _devfs_prepare_leaf(&dir, buf, MODE_DIR);
+ if (!de) {
+ PRINTK("(%s): could not prepare leaf\n", buf);
+ return -EINVAL;
+ }
+
+ error = _devfs_append_entry(dir, de, &old);
+ if (error == -EEXIST && S_ISDIR(old->mode)) {
+ /*
+ * devfs_mk_dir() of an already-existing directory will
+ * return success.
+ */
+ error = 0;
+ goto out_put;
+ } else if (error) {
+ PRINTK("(%s): could not append to dir: %p \"%s\"\n",
+ buf, dir, dir->name);
+ devfs_put(old);
+ goto out_put;
+ }
+
+ devfsd_notify(de, DEVFSD_NOTIFY_REGISTERED);
+
+ out_put:
+ devfs_put(dir);
+ return error;
+}
+
+void devfs_remove(const char *fmt, ...)
+{
+ char buf[64];
+ va_list args;
+ int n;
+
+ va_start(args, fmt);
+ n = vsnprintf(buf, sizeof(buf), fmt, args);
+ if (n < sizeof(buf) && buf[0]) {
+ devfs_handle_t de = _devfs_find_entry(NULL, buf, 0);
+
+ if (!de) {
+ printk(KERN_ERR "%s: %s not found, cannot remove\n",
+ __FUNCTION__, buf);
+ dump_stack();
+ return;
+ }
+
+ write_lock(&de->parent->u.dir.lock);
+ _devfs_unregister(de->parent, de);
+ devfs_put(de);
+ devfs_put(de);
+ }
+}
+
+/**
+ * devfs_generate_path - Generate a pathname for an entry, relative to the devfs root.
+ * @de: The devfs entry.
+ * @path: The buffer to write the pathname to. The pathname and '\0'
+ * terminator will be written at the end of the buffer.
+ * @buflen: The length of the buffer.
+ *
+ * Returns the offset in the buffer where the pathname starts on success,
+ * else a negative error code.
+ */
+
+static int devfs_generate_path(devfs_handle_t de, char *path, int buflen)
+{
+ int pos;
+#define NAMEOF(de) ( (de)->mode ? (de)->name : (de)->u.name )
+
+ if (de == NULL)
+ return -EINVAL;
+ VERIFY_ENTRY(de);
+ if (de->namelen >= buflen)
+ return -ENAMETOOLONG; /* Must be first */
+ path[buflen - 1] = '\0';
+ if (de->parent == NULL)
+ return buflen - 1; /* Don't prepend root */
+ pos = buflen - de->namelen - 1;
+ memcpy(path + pos, NAMEOF(de), de->namelen);
+ for (de = de->parent; de->parent != NULL; de = de->parent) {
+ if (pos - de->namelen - 1 < 0)
+ return -ENAMETOOLONG;
+ path[--pos] = '/';
+ pos -= de->namelen;
+ memcpy(path + pos, NAMEOF(de), de->namelen);
+ }
+ return pos;
+} /* End Function devfs_generate_path */
+
+/**
+ * devfs_setup - Process kernel boot options.
+ * @str: The boot options after the "devfs=".
+ */
+
+static int __init devfs_setup(char *str)
+{
+ static struct {
+ char *name;
+ unsigned int mask;
+ unsigned int *opt;
+ } devfs_options_tab[] __initdata = {
+#ifdef CONFIG_DEVFS_DEBUG
+ {
+ "dall", DEBUG_ALL, &devfs_debug_init}, {
+ "dmod", DEBUG_MODULE_LOAD, &devfs_debug_init}, {
+ "dreg", DEBUG_REGISTER, &devfs_debug_init}, {
+ "dunreg", DEBUG_UNREGISTER, &devfs_debug_init}, {
+ "dfree", DEBUG_FREE, &devfs_debug_init}, {
+ "diget", DEBUG_I_GET, &devfs_debug_init}, {
+ "dchange", DEBUG_SET_FLAGS, &devfs_debug_init}, {
+ "dsread", DEBUG_S_READ, &devfs_debug_init}, {
+ "dichange", DEBUG_I_CHANGE, &devfs_debug_init}, {
+ "dimknod", DEBUG_I_MKNOD, &devfs_debug_init}, {
+ "dilookup", DEBUG_I_LOOKUP, &devfs_debug_init}, {
+ "diunlink", DEBUG_I_UNLINK, &devfs_debug_init},
+#endif /* CONFIG_DEVFS_DEBUG */
+ {
+ "mount", OPTION_MOUNT, &boot_options}, {
+ NULL, 0, NULL}
+ };
+
+ while ((*str != '\0') && !isspace(*str)) {
+ int i, found = 0, invert = 0;
+
+ if (strncmp(str, "no", 2) == 0) {
+ invert = 1;
+ str += 2;
+ }
+ for (i = 0; devfs_options_tab[i].name != NULL; i++) {
+ int len = strlen(devfs_options_tab[i].name);
+
+ if (strncmp(str, devfs_options_tab[i].name, len) == 0) {
+ if (invert)
+ *devfs_options_tab[i].opt &=
+ ~devfs_options_tab[i].mask;
+ else
+ *devfs_options_tab[i].opt |=
+ devfs_options_tab[i].mask;
+ str += len;
+ found = 1;
+ break;
+ }
+ }
+ if (!found)
+ return 0; /* No match */
+ if (*str != ',')
+ return 0; /* No more options */
+ ++str;
+ }
+ return 1;
+} /* End Function devfs_setup */
+
+__setup("devfs=", devfs_setup);
+
+EXPORT_SYMBOL(devfs_mk_dir);
+EXPORT_SYMBOL(devfs_remove);
+
+/**
+ * try_modload - Notify devfsd of an inode lookup by a non-devfsd process.
+ * @parent: The parent devfs entry.
+ * @fs_info: The filesystem info.
+ * @name: The device name.
+ * @namelen: The number of characters in @name.
+ * @buf: A working area that will be used. This must not go out of scope
+ * until devfsd is idle again.
+ *
+ * Returns 0 on success (event was queued), else a negative error code.
+ */
+
+static int try_modload(struct devfs_entry *parent, struct fs_info *fs_info,
+ const char *name, unsigned namelen,
+ struct devfs_entry *buf)
+{
+ if (!(fs_info->devfsd_event_mask & (1 << DEVFSD_NOTIFY_LOOKUP)))
+ return -ENOENT;
+ if (is_devfsd_or_child(fs_info))
+ return -ENOENT;
+ memset(buf, 0, sizeof *buf);
+ atomic_set(&buf->refcount, 1);
+ buf->parent = parent;
+ buf->namelen = namelen;
+ buf->u.name = name;
+ WRITE_ENTRY_MAGIC(buf, MAGIC_VALUE);
+ if (!devfsd_notify_de(buf, DEVFSD_NOTIFY_LOOKUP, 0,
+ current->euid, current->egid, fs_info))
+ return -ENOENT;
+ /* Possible success: event has been queued */
+ return 0;
+} /* End Function try_modload */
+
+/* Superblock operations follow */
+
+static struct inode_operations devfs_iops;
+static struct inode_operations devfs_dir_iops;
+static struct file_operations devfs_fops;
+static struct file_operations devfs_dir_fops;
+static struct inode_operations devfs_symlink_iops;
+
+static int devfs_notify_change(struct dentry *dentry, struct iattr *iattr)
+{
+ int retval;
+ struct devfs_entry *de;
+ struct inode *inode = dentry->d_inode;
+ struct fs_info *fs_info = inode->i_sb->s_fs_info;
+
+ de = get_devfs_entry_from_vfs_inode(inode);
+ if (de == NULL)
+ return -ENODEV;
+ retval = inode_change_ok(inode, iattr);
+ if (retval != 0)
+ return retval;
+ retval = inode_setattr(inode, iattr);
+ if (retval != 0)
+ return retval;
+ DPRINTK(DEBUG_I_CHANGE, "(%d): VFS inode: %p devfs_entry: %p\n",
+ (int)inode->i_ino, inode, de);
+ DPRINTK(DEBUG_I_CHANGE, "(): mode: 0%o uid: %d gid: %d\n",
+ (int)inode->i_mode, (int)inode->i_uid, (int)inode->i_gid);
+ /* Inode is not on hash chains, thus must save permissions here rather
+ than in a write_inode() method */
+ de->mode = inode->i_mode;
+ de->inode.uid = inode->i_uid;
+ de->inode.gid = inode->i_gid;
+ de->inode.atime = inode->i_atime;
+ de->inode.mtime = inode->i_mtime;
+ de->inode.ctime = inode->i_ctime;
+ if ((iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) &&
+ !is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_CHANGE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ return 0;
+} /* End Function devfs_notify_change */
+
+static struct super_operations devfs_sops = {
+ .drop_inode = generic_delete_inode,
+ .statfs = simple_statfs,
+};
+
+/**
+ * _devfs_get_vfs_inode - Get a VFS inode.
+ * @sb: The super block.
+ * @de: The devfs inode.
+ * @dentry: The dentry to register with the devfs inode.
+ *
+ * Returns the inode on success, else %NULL. An implicit devfs_get() is
+ * performed if the inode is created.
+ */
+
+static struct inode *_devfs_get_vfs_inode(struct super_block *sb,
+ struct devfs_entry *de,
+ struct dentry *dentry)
+{
+ struct inode *inode;
+
+ if (de->prev == de)
+ return NULL; /* Quick check to see if unhooked */
+ if ((inode = new_inode(sb)) == NULL) {
+ PRINTK("(%s): new_inode() failed, de: %p\n", de->name, de);
+ return NULL;
+ }
+ if (de->parent) {
+ read_lock(&de->parent->u.dir.lock);
+ if (de->prev != de)
+ de->inode.dentry = dentry; /* Not unhooked */
+ read_unlock(&de->parent->u.dir.lock);
+ } else
+ de->inode.dentry = dentry; /* Root: no locking needed */
+ if (de->inode.dentry != dentry) { /* Must have been unhooked */
+ iput(inode);
+ return NULL;
+ }
+ /* FIXME where is devfs_put? */
+ inode->u.generic_ip = devfs_get(de);
+ inode->i_ino = de->inode.ino;
+ DPRINTK(DEBUG_I_GET, "(%d): VFS inode: %p devfs_entry: %p\n",
+ (int)inode->i_ino, inode, de);
+ inode->i_blocks = 0;
+ inode->i_blksize = FAKE_BLOCK_SIZE;
+ inode->i_op = &devfs_iops;
+ inode->i_mode = de->mode;
+ if (S_ISDIR(de->mode)) {
+ inode->i_op = &devfs_dir_iops;
+ inode->i_fop = &devfs_dir_fops;
+ } else if (S_ISLNK(de->mode)) {
+ inode->i_op = &devfs_symlink_iops;
+ inode->i_size = de->u.symlink.length;
+ } else if (S_ISCHR(de->mode) || S_ISBLK(de->mode)) {
+ init_special_inode(inode, de->mode, de->u.dev);
+ } else if (S_ISFIFO(de->mode) || S_ISSOCK(de->mode)) {
+ init_special_inode(inode, de->mode, 0);
+ } else {
+ PRINTK("(%s): unknown mode %o de: %p\n",
+ de->name, de->mode, de);
+ iput(inode);
+ devfs_put(de);
+ return NULL;
+ }
+
+ inode->i_uid = de->inode.uid;
+ inode->i_gid = de->inode.gid;
+ inode->i_atime = de->inode.atime;
+ inode->i_mtime = de->inode.mtime;
+ inode->i_ctime = de->inode.ctime;
+ DPRINTK(DEBUG_I_GET, "(): mode: 0%o uid: %d gid: %d\n",
+ (int)inode->i_mode, (int)inode->i_uid, (int)inode->i_gid);
+ return inode;
+} /* End Function _devfs_get_vfs_inode */
+
+/* File operations for device entries follow */
+
+static int devfs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+ int err, count;
+ int stored = 0;
+ struct fs_info *fs_info;
+ struct devfs_entry *parent, *de, *next = NULL;
+ struct inode *inode = file->f_dentry->d_inode;
+
+ fs_info = inode->i_sb->s_fs_info;
+ parent = get_devfs_entry_from_vfs_inode(file->f_dentry->d_inode);
+ if ((long)file->f_pos < 0)
+ return -EINVAL;
+ DPRINTK(DEBUG_F_READDIR, "(%s): fs_info: %p pos: %ld\n",
+ parent->name, fs_info, (long)file->f_pos);
+ switch ((long)file->f_pos) {
+ case 0:
+ err = (*filldir) (dirent, "..", 2, file->f_pos,
+ parent_ino(file->f_dentry), DT_DIR);
+ if (err == -EINVAL)
+ break;
+ if (err < 0)
+ return err;
+ file->f_pos++;
+ ++stored;
+ /* Fall through */
+ case 1:
+ err =
+ (*filldir) (dirent, ".", 1, file->f_pos, inode->i_ino,
+ DT_DIR);
+ if (err == -EINVAL)
+ break;
+ if (err < 0)
+ return err;
+ file->f_pos++;
+ ++stored;
+ /* Fall through */
+ default:
+ /* Skip entries */
+ count = file->f_pos - 2;
+ read_lock(&parent->u.dir.lock);
+ for (de = parent->u.dir.first; de && (count > 0); de = de->next)
+ --count;
+ devfs_get(de);
+ read_unlock(&parent->u.dir.lock);
+ /* Now add all remaining entries */
+ while (de) {
+ err = (*filldir) (dirent, de->name, de->namelen,
+ file->f_pos, de->inode.ino,
+ de->mode >> 12);
+ if (err < 0)
+ devfs_put(de);
+ else {
+ file->f_pos++;
+ ++stored;
+ }
+ if (err == -EINVAL)
+ break;
+ if (err < 0)
+ return err;
+ read_lock(&parent->u.dir.lock);
+ next = devfs_get(de->next);
+ read_unlock(&parent->u.dir.lock);
+ devfs_put(de);
+ de = next;
+ }
+ break;
+ }
+ return stored;
+} /* End Function devfs_readdir */
+
+/* Open devfs specific special files */
+static int devfs_open(struct inode *inode, struct file *file)
+{
+ int err;
+ int minor = MINOR(inode->i_rdev);
+ struct file_operations *old_fops, *new_fops;
+
+ switch (minor) {
+ case 0: /* /dev/.devfsd */
+ new_fops = fops_get(&devfsd_fops);
+ break;
+#ifdef CONFIG_DEVFS_DEBUG
+ case 1: /* /dev/.stat */
+ new_fops = fops_get(&stat_fops);
+ break;
+#endif
+ default:
+ return -ENODEV;
+ }
+
+ if (new_fops == NULL)
+ return -ENODEV;
+ old_fops = file->f_op;
+ file->f_op = new_fops;
+ err = new_fops->open ? new_fops->open(inode, file) : 0;
+ if (err) {
+ file->f_op = old_fops;
+ fops_put(new_fops);
+ } else
+ fops_put(old_fops);
+ return err;
+} /* End Function devfs_open */
+
+static struct file_operations devfs_fops = {
+ .open = devfs_open,
+};
+
+static struct file_operations devfs_dir_fops = {
+ .read = generic_read_dir,
+ .readdir = devfs_readdir,
+};
+
+/* Dentry operations for device entries follow */
+
+/**
+ * devfs_d_release - Callback for when a dentry is freed.
+ * @dentry: The dentry.
+ */
+
+static void devfs_d_release(struct dentry *dentry)
+{
+ DPRINTK(DEBUG_D_RELEASE, "(%p): inode: %p\n", dentry, dentry->d_inode);
+} /* End Function devfs_d_release */
+
+/**
+ * devfs_d_iput - Callback for when a dentry loses its inode.
+ * @dentry: The dentry.
+ * @inode: The inode.
+ */
+
+static void devfs_d_iput(struct dentry *dentry, struct inode *inode)
+{
+ struct devfs_entry *de;
+
+ de = get_devfs_entry_from_vfs_inode(inode);
+ DPRINTK(DEBUG_D_IPUT,
+ "(%s): dentry: %p inode: %p de: %p de->dentry: %p\n", de->name,
+ dentry, inode, de, de->inode.dentry);
+ if (de->inode.dentry && (de->inode.dentry != dentry))
+ OOPS("(%s): de: %p dentry: %p de->dentry: %p\n",
+ de->name, de, dentry, de->inode.dentry);
+ de->inode.dentry = NULL;
+ iput(inode);
+ devfs_put(de);
+} /* End Function devfs_d_iput */
+
+static int devfs_d_delete(struct dentry *dentry);
+
+static struct dentry_operations devfs_dops = {
+ .d_delete = devfs_d_delete,
+ .d_release = devfs_d_release,
+ .d_iput = devfs_d_iput,
+};
+
+static int devfs_d_revalidate_wait(struct dentry *dentry, struct nameidata *);
+
+static struct dentry_operations devfs_wait_dops = {
+ .d_delete = devfs_d_delete,
+ .d_release = devfs_d_release,
+ .d_iput = devfs_d_iput,
+ .d_revalidate = devfs_d_revalidate_wait,
+};
+
+/**
+ * devfs_d_delete - Callback for when all files for a dentry are closed.
+ * @dentry: The dentry.
+ */
+
+static int devfs_d_delete(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ if (dentry->d_op == &devfs_wait_dops)
+ dentry->d_op = &devfs_dops;
+ /* Unhash dentry if negative (has no inode) */
+ if (inode == NULL) {
+ DPRINTK(DEBUG_D_DELETE, "(%p): dropping negative dentry\n",
+ dentry);
+ return 1;
+ }
+ return 0;
+} /* End Function devfs_d_delete */
+
+struct devfs_lookup_struct {
+ devfs_handle_t de;
+ wait_queue_head_t wait_queue;
+};
+
+/* XXX: this doesn't handle the case where we got a negative dentry
+ but a devfs entry has been registered in the meanwhile */
+static int devfs_d_revalidate_wait(struct dentry *dentry, struct nameidata *nd)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ devfs_handle_t parent = get_devfs_entry_from_vfs_inode(dir);
+ struct devfs_lookup_struct *lookup_info = dentry->d_fsdata;
+ DECLARE_WAITQUEUE(wait, current);
+ int need_lock;
+
+ /*
+ * FIXME HACK
+ *
+ * make sure that
+ * d_instantiate always runs under lock
+ * we release i_sem lock before going to sleep
+ *
+ * unfortunately sometimes d_revalidate is called with
+ * and sometimes without i_sem lock held. The following checks
+ * attempt to deduce when we need to add (and drop resp.) lock
+ * here. This relies on current (2.6.2) calling coventions:
+ *
+ * lookup_hash is always run under i_sem and is passing NULL
+ * as nd
+ *
+ * open(...,O_CREATE,...) calls _lookup_hash under i_sem
+ * and sets flags to LOOKUP_OPEN|LOOKUP_CREATE
+ *
+ * all other invocations of ->d_revalidate seem to happen
+ * outside of i_sem
+ */
+ need_lock = nd &&
+ (!(nd->flags & LOOKUP_CREATE) || (nd->flags & LOOKUP_PARENT));
+
+ if (need_lock)
+ down(&dir->i_sem);
+
+ if (is_devfsd_or_child(fs_info)) {
+ devfs_handle_t de = lookup_info->de;
+ struct inode *inode;
+
+ DPRINTK(DEBUG_I_LOOKUP,
+ "(%s): dentry: %p inode: %p de: %p by: \"%s\"\n",
+ dentry->d_name.name, dentry, dentry->d_inode, de,
+ current->comm);
+ if (dentry->d_inode)
+ goto out;
+ if (de == NULL) {
+ read_lock(&parent->u.dir.lock);
+ de = _devfs_search_dir(parent, dentry->d_name.name,
+ dentry->d_name.len);
+ read_unlock(&parent->u.dir.lock);
+ if (de == NULL)
+ goto out;
+ lookup_info->de = de;
+ }
+ /* Create an inode, now that the driver information is available */
+ inode = _devfs_get_vfs_inode(dir->i_sb, de, dentry);
+ if (!inode)
+ goto out;
+ DPRINTK(DEBUG_I_LOOKUP,
+ "(%s): new VFS inode(%u): %p de: %p by: \"%s\"\n",
+ de->name, de->inode.ino, inode, de, current->comm);
+ d_instantiate(dentry, inode);
+ goto out;
+ }
+ if (lookup_info == NULL)
+ goto out; /* Early termination */
+ read_lock(&parent->u.dir.lock);
+ if (dentry->d_fsdata) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ add_wait_queue(&lookup_info->wait_queue, &wait);
+ read_unlock(&parent->u.dir.lock);
+ /* at this point it is always (hopefully) locked */
+ up(&dir->i_sem);
+ schedule();
+ down(&dir->i_sem);
+ /*
+ * This does not need nor should remove wait from wait_queue.
+ * Wait queue head is never reused - nothing is ever added to it
+ * after all waiters have been waked up and head itself disappears
+ * very soon after it. Moreover it is local variable on stack that
+ * is likely to have already disappeared so any reference to it
+ * at this point is buggy.
+ */
+
+ } else
+ read_unlock(&parent->u.dir.lock);
+
+ out:
+ if (need_lock)
+ up(&dir->i_sem);
+ return 1;
+} /* End Function devfs_d_revalidate_wait */
+
+/* Inode operations for device entries follow */
+
+static struct dentry *devfs_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct devfs_entry tmp; /* Must stay in scope until devfsd idle again */
+ struct devfs_lookup_struct lookup_info;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ struct devfs_entry *parent, *de;
+ struct inode *inode;
+ struct dentry *retval = NULL;
+
+ /* Set up the dentry operations before anything else, to ensure cleaning
+ up on any error */
+ dentry->d_op = &devfs_dops;
+ /* First try to get the devfs entry for this directory */
+ parent = get_devfs_entry_from_vfs_inode(dir);
+ DPRINTK(DEBUG_I_LOOKUP, "(%s): dentry: %p parent: %p by: \"%s\"\n",
+ dentry->d_name.name, dentry, parent, current->comm);
+ if (parent == NULL)
+ return ERR_PTR(-ENOENT);
+ read_lock(&parent->u.dir.lock);
+ de = _devfs_search_dir(parent, dentry->d_name.name, dentry->d_name.len);
+ read_unlock(&parent->u.dir.lock);
+ lookup_info.de = de;
+ init_waitqueue_head(&lookup_info.wait_queue);
+ dentry->d_fsdata = &lookup_info;
+ if (de == NULL) { /* Try with devfsd. For any kind of failure, leave a negative dentry
+ so someone else can deal with it (in the case where the sysadmin
+ does a mknod()). It's important to do this before hashing the
+ dentry, so that the devfsd queue is filled before revalidates
+ can start */
+ if (try_modload(parent, fs_info, dentry->d_name.name, dentry->d_name.len, &tmp) < 0) { /* Lookup event was not queued to devfsd */
+ d_add(dentry, NULL);
+ return NULL;
+ }
+ }
+ dentry->d_op = &devfs_wait_dops;
+ d_add(dentry, NULL); /* Open the floodgates */
+ /* Unlock directory semaphore, which will release any waiters. They
+ will get the hashed dentry, and may be forced to wait for
+ revalidation */
+ up(&dir->i_sem);
+ wait_for_devfsd_finished(fs_info); /* If I'm not devfsd, must wait */
+ down(&dir->i_sem); /* Grab it again because them's the rules */
+ de = lookup_info.de;
+ /* If someone else has been so kind as to make the inode, we go home
+ early */
+ if (dentry->d_inode)
+ goto out;
+ if (de == NULL) {
+ read_lock(&parent->u.dir.lock);
+ de = _devfs_search_dir(parent, dentry->d_name.name,
+ dentry->d_name.len);
+ read_unlock(&parent->u.dir.lock);
+ if (de == NULL)
+ goto out;
+ /* OK, there's an entry now, but no VFS inode yet */
+ }
+ /* Create an inode, now that the driver information is available */
+ inode = _devfs_get_vfs_inode(dir->i_sb, de, dentry);
+ if (!inode) {
+ retval = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ DPRINTK(DEBUG_I_LOOKUP,
+ "(%s): new VFS inode(%u): %p de: %p by: \"%s\"\n", de->name,
+ de->inode.ino, inode, de, current->comm);
+ d_instantiate(dentry, inode);
+ out:
+ write_lock(&parent->u.dir.lock);
+ dentry->d_op = &devfs_dops;
+ dentry->d_fsdata = NULL;
+ wake_up(&lookup_info.wait_queue);
+ write_unlock(&parent->u.dir.lock);
+ devfs_put(de);
+ return retval;
+} /* End Function devfs_lookup */
+
+static int devfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ int unhooked;
+ struct devfs_entry *de;
+ struct inode *inode = dentry->d_inode;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+
+ de = get_devfs_entry_from_vfs_inode(inode);
+ DPRINTK(DEBUG_I_UNLINK, "(%s): de: %p\n", dentry->d_name.name, de);
+ if (de == NULL)
+ return -ENOENT;
+ if (!de->vfs)
+ return -EPERM;
+ write_lock(&de->parent->u.dir.lock);
+ unhooked = _devfs_unhook(de);
+ write_unlock(&de->parent->u.dir.lock);
+ if (!unhooked)
+ return -ENOENT;
+ if (!is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ free_dentry(de);
+ devfs_put(de);
+ return 0;
+} /* End Function devfs_unlink */
+
+static int devfs_symlink(struct inode *dir, struct dentry *dentry,
+ const char *symname)
+{
+ int err;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ struct devfs_entry *parent, *de;
+ struct inode *inode;
+
+ /* First try to get the devfs entry for this directory */
+ parent = get_devfs_entry_from_vfs_inode(dir);
+ if (parent == NULL)
+ return -ENOENT;
+ err = devfs_do_symlink(parent, dentry->d_name.name, symname, &de);
+ DPRINTK(DEBUG_DISABLED, "(%s): errcode from <devfs_do_symlink>: %d\n",
+ dentry->d_name.name, err);
+ if (err < 0)
+ return err;
+ de->vfs = TRUE;
+ de->inode.uid = current->euid;
+ de->inode.gid = current->egid;
+ de->inode.atime = CURRENT_TIME;
+ de->inode.mtime = CURRENT_TIME;
+ de->inode.ctime = CURRENT_TIME;
+ if ((inode = _devfs_get_vfs_inode(dir->i_sb, de, dentry)) == NULL)
+ return -ENOMEM;
+ DPRINTK(DEBUG_DISABLED, "(%s): new VFS inode(%u): %p dentry: %p\n",
+ dentry->d_name.name, de->inode.ino, inode, dentry);
+ d_instantiate(dentry, inode);
+ if (!is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ return 0;
+} /* End Function devfs_symlink */
+
+static int devfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ int err;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ struct devfs_entry *parent, *de;
+ struct inode *inode;
+
+ mode = (mode & ~S_IFMT) | S_IFDIR; /* VFS doesn't pass S_IFMT part */
+ parent = get_devfs_entry_from_vfs_inode(dir);
+ if (parent == NULL)
+ return -ENOENT;
+ de = _devfs_alloc_entry(dentry->d_name.name, dentry->d_name.len, mode);
+ if (!de)
+ return -ENOMEM;
+ de->vfs = TRUE;
+ if ((err = _devfs_append_entry(parent, de, NULL)) != 0)
+ return err;
+ de->inode.uid = current->euid;
+ de->inode.gid = current->egid;
+ de->inode.atime = CURRENT_TIME;
+ de->inode.mtime = CURRENT_TIME;
+ de->inode.ctime = CURRENT_TIME;
+ if ((inode = _devfs_get_vfs_inode(dir->i_sb, de, dentry)) == NULL)
+ return -ENOMEM;
+ DPRINTK(DEBUG_DISABLED, "(%s): new VFS inode(%u): %p dentry: %p\n",
+ dentry->d_name.name, de->inode.ino, inode, dentry);
+ d_instantiate(dentry, inode);
+ if (!is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ return 0;
+} /* End Function devfs_mkdir */
+
+static int devfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ int err = 0;
+ struct devfs_entry *de;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ struct inode *inode = dentry->d_inode;
+
+ if (dir->i_sb->s_fs_info != inode->i_sb->s_fs_info)
+ return -EINVAL;
+ de = get_devfs_entry_from_vfs_inode(inode);
+ if (de == NULL)
+ return -ENOENT;
+ if (!S_ISDIR(de->mode))
+ return -ENOTDIR;
+ if (!de->vfs)
+ return -EPERM;
+ /* First ensure the directory is empty and will stay that way */
+ write_lock(&de->u.dir.lock);
+ if (de->u.dir.first)
+ err = -ENOTEMPTY;
+ else
+ de->u.dir.no_more_additions = TRUE;
+ write_unlock(&de->u.dir.lock);
+ if (err)
+ return err;
+ /* Now unhook the directory from its parent */
+ write_lock(&de->parent->u.dir.lock);
+ if (!_devfs_unhook(de))
+ err = -ENOENT;
+ write_unlock(&de->parent->u.dir.lock);
+ if (err)
+ return err;
+ if (!is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_DELETE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ free_dentry(de);
+ devfs_put(de);
+ return 0;
+} /* End Function devfs_rmdir */
+
+static int devfs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+ dev_t rdev)
+{
+ int err;
+ struct fs_info *fs_info = dir->i_sb->s_fs_info;
+ struct devfs_entry *parent, *de;
+ struct inode *inode;
+
+ DPRINTK(DEBUG_I_MKNOD, "(%s): mode: 0%o dev: %u:%u\n",
+ dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
+ parent = get_devfs_entry_from_vfs_inode(dir);
+ if (parent == NULL)
+ return -ENOENT;
+ de = _devfs_alloc_entry(dentry->d_name.name, dentry->d_name.len, mode);
+ if (!de)
+ return -ENOMEM;
+ de->vfs = TRUE;
+ if (S_ISCHR(mode) || S_ISBLK(mode))
+ de->u.dev = rdev;
+ if ((err = _devfs_append_entry(parent, de, NULL)) != 0)
+ return err;
+ de->inode.uid = current->euid;
+ de->inode.gid = current->egid;
+ de->inode.atime = CURRENT_TIME;
+ de->inode.mtime = CURRENT_TIME;
+ de->inode.ctime = CURRENT_TIME;
+ if ((inode = _devfs_get_vfs_inode(dir->i_sb, de, dentry)) == NULL)
+ return -ENOMEM;
+ DPRINTK(DEBUG_I_MKNOD, ": new VFS inode(%u): %p dentry: %p\n",
+ de->inode.ino, inode, dentry);
+ d_instantiate(dentry, inode);
+ if (!is_devfsd_or_child(fs_info))
+ devfsd_notify_de(de, DEVFSD_NOTIFY_CREATE, inode->i_mode,
+ inode->i_uid, inode->i_gid, fs_info);
+ return 0;
+} /* End Function devfs_mknod */
+
+static int devfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ struct devfs_entry *p = get_devfs_entry_from_vfs_inode(dentry->d_inode);
+ nd_set_link(nd, p ? p->u.symlink.linkname : ERR_PTR(-ENODEV));
+ return 0;
+} /* End Function devfs_follow_link */
+
+static struct inode_operations devfs_iops = {
+ .setattr = devfs_notify_change,
+};
+
+static struct inode_operations devfs_dir_iops = {
+ .lookup = devfs_lookup,
+ .unlink = devfs_unlink,
+ .symlink = devfs_symlink,
+ .mkdir = devfs_mkdir,
+ .rmdir = devfs_rmdir,
+ .mknod = devfs_mknod,
+ .setattr = devfs_notify_change,
+};
+
+static struct inode_operations devfs_symlink_iops = {
+ .readlink = generic_readlink,
+ .follow_link = devfs_follow_link,
+ .setattr = devfs_notify_change,
+};
+
+static int devfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *root_inode = NULL;
+
+ if (_devfs_get_root_entry() == NULL)
+ goto out_no_root;
+ atomic_set(&fs_info.devfsd_overrun_count, 0);
+ init_waitqueue_head(&fs_info.devfsd_wait_queue);
+ init_waitqueue_head(&fs_info.revalidate_wait_queue);
+ fs_info.sb = sb;
+ sb->s_fs_info = &fs_info;
+ sb->s_blocksize = 1024;
+ sb->s_blocksize_bits = 10;
+ sb->s_magic = DEVFS_SUPER_MAGIC;
+ sb->s_op = &devfs_sops;
+ sb->s_time_gran = 1;
+ if ((root_inode = _devfs_get_vfs_inode(sb, root_entry, NULL)) == NULL)
+ goto out_no_root;
+ sb->s_root = d_alloc_root(root_inode);
+ if (!sb->s_root)
+ goto out_no_root;
+ DPRINTK(DEBUG_S_READ, "(): made devfs ptr: %p\n", sb->s_fs_info);
+ return 0;
+
+ out_no_root:
+ PRINTK("(): get root inode failed\n");
+ if (root_inode)
+ iput(root_inode);
+ return -EINVAL;
+} /* End Function devfs_fill_super */
+
+static struct super_block *devfs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, devfs_fill_super);
+}
+
+static struct file_system_type devfs_fs_type = {
+ .name = DEVFS_NAME,
+ .get_sb = devfs_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+/* File operations for devfsd follow */
+
+static ssize_t devfsd_read(struct file *file, char __user *buf, size_t len,
+ loff_t * ppos)
+{
+ int done = FALSE;
+ int ival;
+ loff_t pos, devname_offset, tlen, rpos;
+ devfs_handle_t de;
+ struct devfsd_buf_entry *entry;
+ struct fs_info *fs_info = file->f_dentry->d_inode->i_sb->s_fs_info;
+ struct devfsd_notify_struct *info = fs_info->devfsd_info;
+ DECLARE_WAITQUEUE(wait, current);
+
+ /* Verify the task has grabbed the queue */
+ if (fs_info->devfsd_task != current)
+ return -EPERM;
+ info->major = 0;
+ info->minor = 0;
+ /* Block for a new entry */
+ set_current_state(TASK_INTERRUPTIBLE);
+ add_wait_queue(&fs_info->devfsd_wait_queue, &wait);
+ while (devfsd_queue_empty(fs_info)) {
+ fs_info->devfsd_sleeping = TRUE;
+ wake_up(&fs_info->revalidate_wait_queue);
+ schedule();
+ fs_info->devfsd_sleeping = FALSE;
+ if (signal_pending(current)) {
+ remove_wait_queue(&fs_info->devfsd_wait_queue, &wait);
+ __set_current_state(TASK_RUNNING);
+ return -EINTR;
+ }
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+ remove_wait_queue(&fs_info->devfsd_wait_queue, &wait);
+ __set_current_state(TASK_RUNNING);
+ /* Now play with the data */
+ ival = atomic_read(&fs_info->devfsd_overrun_count);
+ info->overrun_count = ival;
+ entry = fs_info->devfsd_first_event;
+ info->type = entry->type;
+ info->mode = entry->mode;
+ info->uid = entry->uid;
+ info->gid = entry->gid;
+ de = entry->de;
+ if (S_ISCHR(de->mode) || S_ISBLK(de->mode)) {
+ info->major = MAJOR(de->u.dev);
+ info->minor = MINOR(de->u.dev);
+ }
+ pos = devfs_generate_path(de, info->devname, DEVFS_PATHLEN);
+ if (pos < 0)
+ return pos;
+ info->namelen = DEVFS_PATHLEN - pos - 1;
+ if (info->mode == 0)
+ info->mode = de->mode;
+ devname_offset = info->devname - (char *)info;
+ rpos = *ppos;
+ if (rpos < devname_offset) {
+ /* Copy parts of the header */
+ tlen = devname_offset - rpos;
+ if (tlen > len)
+ tlen = len;
+ if (copy_to_user(buf, (char *)info + rpos, tlen)) {
+ return -EFAULT;
+ }
+ rpos += tlen;
+ buf += tlen;
+ len -= tlen;
+ }
+ if ((rpos >= devname_offset) && (len > 0)) {
+ /* Copy the name */
+ tlen = info->namelen + 1;
+ if (tlen > len)
+ tlen = len;
+ else
+ done = TRUE;
+ if (copy_to_user
+ (buf, info->devname + pos + rpos - devname_offset, tlen)) {
+ return -EFAULT;
+ }
+ rpos += tlen;
+ }
+ tlen = rpos - *ppos;
+ if (done) {
+ devfs_handle_t parent;
+
+ spin_lock(&fs_info->devfsd_buffer_lock);
+ fs_info->devfsd_first_event = entry->next;
+ if (entry->next == NULL)
+ fs_info->devfsd_last_event = NULL;
+ spin_unlock(&fs_info->devfsd_buffer_lock);
+ for (; de != NULL; de = parent) {
+ parent = de->parent;
+ devfs_put(de);
+ }
+ kmem_cache_free(devfsd_buf_cache, entry);
+ if (ival > 0)
+ atomic_sub(ival, &fs_info->devfsd_overrun_count);
+ *ppos = 0;
+ } else
+ *ppos = rpos;
+ return tlen;
+} /* End Function devfsd_read */
+
+static int devfsd_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int ival;
+ struct fs_info *fs_info = inode->i_sb->s_fs_info;
+
+ switch (cmd) {
+ case DEVFSDIOC_GET_PROTO_REV:
+ ival = DEVFSD_PROTOCOL_REVISION_KERNEL;
+ if (copy_to_user((void __user *)arg, &ival, sizeof ival))
+ return -EFAULT;
+ break;
+ case DEVFSDIOC_SET_EVENT_MASK:
+ /* Ensure only one reader has access to the queue. This scheme will
+ work even if the global kernel lock were to be removed, because it
+ doesn't matter who gets in first, as long as only one gets it */
+ if (fs_info->devfsd_task == NULL) {
+ static DEFINE_SPINLOCK(lock);
+
+ if (!spin_trylock(&lock))
+ return -EBUSY;
+ if (fs_info->devfsd_task != NULL) { /* We lost the race... */
+ spin_unlock(&lock);
+ return -EBUSY;
+ }
+ fs_info->devfsd_task = current;
+ spin_unlock(&lock);
+ fs_info->devfsd_pgrp =
+ (process_group(current) ==
+ current->pid) ? process_group(current) : 0;
+ fs_info->devfsd_file = file;
+ fs_info->devfsd_info =
+ kmalloc(sizeof *fs_info->devfsd_info, GFP_KERNEL);
+ if (!fs_info->devfsd_info) {
+ devfsd_close(inode, file);
+ return -ENOMEM;
+ }
+ } else if (fs_info->devfsd_task != current)
+ return -EBUSY;
+ fs_info->devfsd_event_mask = arg; /* Let the masses come forth */
+ break;
+ case DEVFSDIOC_RELEASE_EVENT_QUEUE:
+ if (fs_info->devfsd_file != file)
+ return -EPERM;
+ return devfsd_close(inode, file);
+ /*break; */
+#ifdef CONFIG_DEVFS_DEBUG
+ case DEVFSDIOC_SET_DEBUG_MASK:
+ if (copy_from_user(&ival, (void __user *)arg, sizeof ival))
+ return -EFAULT;
+ devfs_debug = ival;
+ break;
+#endif
+ default:
+ return -ENOIOCTLCMD;
+ }
+ return 0;
+} /* End Function devfsd_ioctl */
+
+static int devfsd_close(struct inode *inode, struct file *file)
+{
+ struct devfsd_buf_entry *entry, *next;
+ struct fs_info *fs_info = inode->i_sb->s_fs_info;
+
+ if (fs_info->devfsd_file != file)
+ return 0;
+ fs_info->devfsd_event_mask = 0;
+ fs_info->devfsd_file = NULL;
+ spin_lock(&fs_info->devfsd_buffer_lock);
+ entry = fs_info->devfsd_first_event;
+ fs_info->devfsd_first_event = NULL;
+ fs_info->devfsd_last_event = NULL;
+ if (fs_info->devfsd_info) {
+ kfree(fs_info->devfsd_info);
+ fs_info->devfsd_info = NULL;
+ }
+ spin_unlock(&fs_info->devfsd_buffer_lock);
+ fs_info->devfsd_pgrp = 0;
+ fs_info->devfsd_task = NULL;
+ wake_up(&fs_info->revalidate_wait_queue);
+ for (; entry; entry = next) {
+ next = entry->next;
+ kmem_cache_free(devfsd_buf_cache, entry);
+ }
+ return 0;
+} /* End Function devfsd_close */
+
+#ifdef CONFIG_DEVFS_DEBUG
+static ssize_t stat_read(struct file *file, char __user *buf, size_t len,
+ loff_t * ppos)
+{
+ ssize_t num;
+ char txt[80];
+
+ num = sprintf(txt, "Number of entries: %u number of bytes: %u\n",
+ stat_num_entries, stat_num_bytes) + 1;
+ if (*ppos >= num)
+ return 0;
+ if (*ppos + len > num)
+ len = num - *ppos;
+ if (copy_to_user(buf, txt + *ppos, len))
+ return -EFAULT;
+ *ppos += len;
+ return len;
+} /* End Function stat_read */
+#endif
+
+static int __init init_devfs_fs(void)
+{
+ int err;
+ int major;
+ struct devfs_entry *devfsd;
+#ifdef CONFIG_DEVFS_DEBUG
+ struct devfs_entry *stat;
+#endif
+
+ if (_devfs_get_root_entry() == NULL)
+ return -ENOMEM;
+
+ printk(KERN_INFO "%s: %s Richard Gooch (rgooch@atnf.csiro.au)\n",
+ DEVFS_NAME, DEVFS_VERSION);
+ devfsd_buf_cache = kmem_cache_create("devfsd_event",
+ sizeof(struct devfsd_buf_entry),
+ 0, 0, NULL, NULL);
+ if (!devfsd_buf_cache)
+ OOPS("(): unable to allocate event slab\n");
+#ifdef CONFIG_DEVFS_DEBUG
+ devfs_debug = devfs_debug_init;
+ printk(KERN_INFO "%s: devfs_debug: 0x%0x\n", DEVFS_NAME, devfs_debug);
+#endif
+ printk(KERN_INFO "%s: boot_options: 0x%0x\n", DEVFS_NAME, boot_options);
+
+ /* register special device for devfsd communication */
+ major = register_chrdev(0, "devfs", &devfs_fops);
+ if (major < 0)
+ return major;
+
+ /* And create the entry for ".devfsd" */
+ devfsd = _devfs_alloc_entry(".devfsd", 0, S_IFCHR | S_IRUSR | S_IWUSR);
+ if (devfsd == NULL)
+ return -ENOMEM;
+ devfsd->u.dev = MKDEV(major, 0);
+ _devfs_append_entry(root_entry, devfsd, NULL);
+
+#ifdef CONFIG_DEVFS_DEBUG
+ stat = _devfs_alloc_entry(".stat", 0, S_IFCHR | S_IRUGO);
+ if (stat == NULL)
+ return -ENOMEM;
+ stat->u.dev = MKDEV(major, 1);
+ _devfs_append_entry(root_entry, stat, NULL);
+#endif
+
+ err = register_filesystem(&devfs_fs_type);
+ return err;
+} /* End Function init_devfs_fs */
+
+void __init mount_devfs_fs(void)
+{
+ int err;
+
+ if (!(boot_options & OPTION_MOUNT))
+ return;
+ err = do_mount("none", "/dev", "devfs", 0, NULL);
+ if (err == 0)
+ printk(KERN_INFO "Mounted devfs on /dev\n");
+ else
+ PRINTK("(): unable to mount devfs, err: %d\n", err);
+} /* End Function mount_devfs_fs */
+
+module_init(init_devfs_fs)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 08:22:26 +0000