diff options
| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/devfs/base.c | |
| download | kernel-common-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel-common-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 kernel-common-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip | |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/devfs/base.c')
| -rw-r--r-- | fs/devfs/base.c | 2838 |
1 files changed, 2838 insertions, 0 deletions
diff --git a/fs/devfs/base.c b/fs/devfs/base.c new file mode 100644 index 000000000000..1ecfe1f184d4 --- /dev/null +++ b/fs/devfs/base.c @@ -0,0 +1,2838 @@ +/* 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) |