base.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,003 行 · 第 1/5 页

  v0.86
    19991204   Richard Gooch <[e-mail]>
	       Support fifos when unregistering.
	       Work sponsored by SGI.
  v0.87
    19991209   Richard Gooch <[e-mail]>
	       Removed obsolete DEVFS_ FL_COMPAT and DEVFS_ FL_TOLERANT flags.
	       Work sponsored by SGI.
  v0.88
    19991214   Richard Gooch <[e-mail]>
	       Removed kmod support.
	       Work sponsored by SGI.
  v0.89
    19991216   Richard Gooch <[e-mail]>
	       Improved debugging in <get_vfs_inode>.
	       Ensure dentries created by devfsd will be cleaned up.
	       Work sponsored by SGI.
  v0.90
    19991223   Richard Gooch <[e-mail]>
	       Created <devfs_get_name>.
	       Work sponsored by SGI.
  v0.91
    20000203   Richard Gooch <[e-mail]>
	       Ported to kernel 2.3.42.
	       Removed <devfs_fill_file>.
	       Work sponsored by SGI.
  v0.92
    20000306   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Set inode->i_size to correct size for symlinks.
    20000414   Richard Gooch <[e-mail]>
	       Only give lookup() method to directories to comply with new VFS
	       assumptions.
	       Work sponsored by SGI.
    20000415   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Don't create missing directories in <devfs_find_handle>.
	       Work sponsored by SGI.
  v0.95
    20000430   Richard Gooch <[e-mail]>
	       Added CONFIG_DEVFS_MOUNT.
	       Work sponsored by SGI.
  v0.96
    20000608   Richard Gooch <[e-mail]>
	       Disabled multi-mount capability (use VFS bindings instead).
	       Work sponsored by SGI.
  v0.97
    20000610   Richard Gooch <[e-mail]>
	       Switched to FS_SINGLE to disable multi-mounts.
    20000612   Richard Gooch <[e-mail]>
	       Removed module support.
	       Removed multi-mount code.
	       Removed compatibility macros: VFS has changed too much.
	       Work sponsored by SGI.
  v0.98
    20000614   Richard Gooch <[e-mail]>
	       Merged devfs inode into devfs entry.
	       Work sponsored by SGI.
  v0.99
    20000619   Richard Gooch <[e-mail]>
	       Removed dead code in <devfs_register> which used to call
	       <free_dentries>.
	       Work sponsored by SGI.
  v0.100
    20000621   Richard Gooch <[e-mail]>
	       Changed interface to <devfs_register>.
	       Work sponsored by SGI.
  v0.101
    20000622   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Ensure <devfs_generate_path> terminates string for root entry.
	       Exported <devfs_get_name> to modules.
    20010520   Richard Gooch <[e-mail]>
	       Make <devfs_mk_symlink> send events to devfsd.
	       Cleaned up option processing in <devfs_setup>.
    20010521   Richard Gooch <[e-mail]>
	       Fixed bugs in handling symlinks: could leak or cause Oops.
    20010522   Richard Gooch <[e-mail]>
	       Cleaned up directory handling by separating fops.
  v0.103
    20010601   Richard Gooch <[e-mail]>
	       Fixed handling of inverted options in <devfs_setup>.
  v0.104
    20010604   Richard Gooch <[e-mail]>
	       Adjusted <try_modload> to account for <devfs_generate_path> fix.
  v0.105
    20010617   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Removed broken devnum allocation and use <devfs_alloc_devnum>.
	       Fixed old devnum leak by calling new <devfs_dealloc_devnum>.
  v0.107
    20010712   Richard Gooch <[e-mail]>
	       Fixed bug in <devfs_setup> which could hang boot process.
  v0.108
    20010730   Richard Gooch <[e-mail]>
	       Added DEVFSD_NOTIFY_DELETE event.
    20010801   Richard Gooch <[e-mail]>
	       Removed #include <asm/segment.h>.
  v0.109
    20010807   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Fixed race in <devfs_do_symlink> for uni-processor.
  v0.111
    20010818   Richard Gooch <[e-mail]>
	       Removed remnant of multi-mount support in <devfs_mknod>.
               Removed unused DEVFS_FL_SHOW_UNREG flag.
  v0.112
    20010820   Richard Gooch <[e-mail]>
	       Removed nlink field from struct devfs_inode.
  v0.113
    20010823   Richard Gooch <[e-mail]>
	       Replaced BKL with global rwsem to protect symlink data (quick
	       and dirty hack).
  v0.114
    20010827   Richard Gooch <[e-mail]>
	       Replaced global rwsem for symlink with per-link refcount.
  v0.115
    20010919   Richard Gooch <[e-mail]>
	       Set inode->i_mapping->a_ops for block nodes in <get_vfs_inode>.
  v0.116
    20011008   Richard Gooch <[e-mail]>
	       Fixed overrun in <devfs_link> by removing function (not needed).
    20011009   Richard Gooch <[e-mail]>
	       Fixed buffer underrun in <try_modload>.
    20011029   Richard Gooch <[e-mail]>
	       Fixed race in <devfsd_ioctl> when setting event mask.
    20011114   Richard Gooch <[e-mail]>
	       First release of new locking code.
  v1.0
    20011117   Richard Gooch <[e-mail]>
	       Discard temporary buffer, now use "%s" for dentry names.
    20011118   Richard Gooch <[e-mail]>
	       Don't generate path in <try_modload>: use fake entry instead.
	       Use "existing" directory in <_devfs_make_parent_for_leaf>.
    20011122   Richard Gooch <[e-mail]>
	       Use slab cache rather than fixed buffer for devfsd events.
  v1.1
    20011125   Richard Gooch <[e-mail]>
	       Send DEVFSD_NOTIFY_REGISTERED events in <devfs_mk_dir>.
    20011127   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Fixed bug in <devfsd_read>: was dereferencing freed pointer.
  v1.3
    20011203   Richard Gooch <[e-mail]>
	       Fixed bug in <devfsd_close>: was dereferencing freed pointer.
	       Added process group check for devfsd privileges.
  v1.4
    20011204   Richard Gooch <[e-mail]>
	       Use SLAB_ATOMIC in <devfsd_notify_de> from <devfs_d_delete>.
  v1.5
    20011211   Richard Gooch <[e-mail]>
	       Return old entry in <devfs_mk_dir> for 2.4.x kernels.
    20011212   Richard Gooch <[e-mail]>
	       Increment refcount on module in <check_disc_changed>.
    20011215   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Added poisoning to <devfs_put>.
	       Improved debugging messages.
  v1.7
    20011221   Richard Gooch <[e-mail]>
	       Corrected (made useful) debugging message in <unregister>.
	       Moved <kmem_cache_create> in <mount_devfs_fs> to <init_devfs_fs>
    20011224   Richard Gooch <[e-mail]>
	       Added magic number to guard against scribbling drivers.
    20011226   Richard Gooch <[e-mail]>
	       Only return old entry in <devfs_mk_dir> if a directory.
	       Defined macros for error and debug messages.
  v1.8
    20020113   Richard Gooch <[e-mail]>
	       Fixed (rare, old) race in <devfs_lookup>.
  v1.9
    20020120   Richard Gooch <[e-mail]>
	       Fixed deadlock bug in <devfs_d_revalidate_wait>.
	       Tag VFS deletable in <devfs_mk_symlink> if handle ignored.
  v1.10
    20020129   Richard Gooch <[e-mail]>
	       Added KERN_* to remaining messages.
	       Cleaned up declaration of <stat_read>.
  v1.11
    20020219   Richard Gooch <[e-mail]>
	       Changed <devfs_rmdir> to allow later additions if not yet empty.
  v1.12
    20020406   Richard Gooch <[e-mail]>
	       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 <[e-mail]>
	       Removed 2.4.x compatibility code.
  v1.14
    20020510   Richard Gooch <[e-mail]>
	       Added BKL to <devfs_open> because drivers still need it.
  v1.15
    20020512   Richard Gooch <[e-mail]>
	       Protected <scan_dir_for_removable> and <get_removable_partition>
	       from changing directory contents.
  v1.16
    20020514   Richard Gooch <[e-mail]>
	       Minor cleanup of <scan_dir_for_removable>.
  v1.17
    20020721   Richard Gooch <[e-mail]>
	       Switched to ISO C structure field initialisers.
	       Switch to set_current_state() and move before add_wait_queue().
    20020722   Richard Gooch <[e-mail]>
	       Fixed devfs entry leak in <devfs_readdir> when *readdir fails.
  v1.18
    20020725   Richard Gooch <[e-mail]>
	       Created <devfs_find_and_unregister>.
  v1.19
    20020728   Richard Gooch <[e-mail]>
	       Removed deprecated <devfs_find_handle>.
  v1.20
    20020820   Richard Gooch <[e-mail]>
	       Fixed module unload race in <devfs_open>.
  v1.21
    20021013   Richard Gooch <[e-mail]>
	       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 <asm/uaccess.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/bitops.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;