LCOV - code coverage report
Current view: top level - lkbce/include/linux - fdtable.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 2 2 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : /*
       2             :  * descriptor table internals; you almost certainly want file.h instead.
       3             :  */
       4             : 
       5             : #ifndef __LINUX_FDTABLE_H
       6             : #define __LINUX_FDTABLE_H
       7             : 
       8             : #include <linux/posix_types.h>
       9             : #include <linux/compiler.h>
      10             : #include <linux/spinlock.h>
      11             : #include <linux/rcupdate.h>
      12             : #include <linux/types.h>
      13             : #include <linux/init.h>
      14             : 
      15             : #include <asm/atomic.h>
      16             : 
      17             : /*
      18             :  * The default fd array needs to be at least BITS_PER_LONG,
      19             :  * as this is the granularity returned by copy_fdset().
      20             :  */
      21             : #define NR_OPEN_DEFAULT BITS_PER_LONG
      22             : 
      23             : /*
      24             :  * The embedded_fd_set is a small fd_set,
      25             :  * suitable for most tasks (which open <= BITS_PER_LONG files)
      26             :  */
      27             : struct embedded_fd_set {
      28             :         unsigned long fds_bits[1];
      29             : };
      30           1 : 
      31             : struct fdtable {
      32             :         unsigned int max_fds;
      33             :         struct file ** fd;      /* current fd array */
      34             :         fd_set *close_on_exec;
      35             :         fd_set *open_fds;
      36             :         struct rcu_head rcu;
      37             :         struct fdtable *next;
      38             : };
      39           1 : 
      40             : /*
      41             :  * Open file table structure
      42             :  */
      43             : struct files_struct {
      44             :   /*
      45             :    * read mostly part
      46             :    */
      47             :         atomic_t count;
      48             :         struct fdtable *fdt;
      49             :         struct fdtable fdtab;
      50             :   /*
      51             :    * written part on a separate cache line in SMP
      52             :    */
      53             :         spinlock_t file_lock ____cacheline_aligned_in_smp;
      54             :         int next_fd;
      55             :         struct embedded_fd_set close_on_exec_init;
      56             :         struct embedded_fd_set open_fds_init;
      57             :         struct file * fd_array[NR_OPEN_DEFAULT];
      58             : };
      59             : 
      60             : #define files_fdtable(files) (rcu_dereference((files)->fdt))
      61             : 
      62             : struct file_operations;
      63             : struct vfsmount;
      64             : struct dentry;
      65             : 
      66             : extern int expand_files(struct files_struct *, int nr);
      67             : extern void free_fdtable_rcu(struct rcu_head *rcu);
      68             : extern void __init files_defer_init(void);
      69             : 
      70             : static inline void free_fdtable(struct fdtable *fdt)
      71             : {
      72             :         call_rcu(&fdt->rcu, free_fdtable_rcu);
      73             : }
      74             : 
      75             : static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
      76             : {
      77             :         struct file * file = NULL;
      78             :         struct fdtable *fdt = files_fdtable(files);
      79             : 
      80             :         if (fd < fdt->max_fds)
      81             :                 file = rcu_dereference(fdt->fd[fd]);
      82             :         return file;
      83             : }
      84             : 
      85             : /*
      86             :  * Check whether the specified fd has an open file.
      87             :  */
      88             : #define fcheck(fd)      fcheck_files(current->files, fd)
      89             : 
      90             : struct task_struct;
      91             : 
      92             : struct files_struct *get_files_struct(struct task_struct *);
      93             : void put_files_struct(struct files_struct *fs);
      94             : void reset_files_struct(struct files_struct *);
      95             : int unshare_files(struct files_struct **);
      96             : struct files_struct *dup_fd(struct files_struct *, int *);
      97             : 
      98             : extern struct kmem_cache *files_cachep;
      99             : 
     100             : #endif /* __LINUX_FDTABLE_H */

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