include/linux/pid.h

   1 #ifndef _LINUX_PID_H
   2 #define _LINUX_PID_H
   3
   4 enum pid_type
   5 {
   6         PIDTYPE_PID,
   7         PIDTYPE_TGID,
   8         PIDTYPE_PGID,
   9         PIDTYPE_SID,
  10         PIDTYPE_MAX
  11 };
  12
  13 struct pid
  14 {
  15         int nr;
  16         atomic_t count;
  17         struct task_struct *task;
  18         struct list_head task_list;
  19         struct list_head hash_chain;
  20 };
  21
  22 struct pid_link
  23 {
  24         struct list_head pid_chain;
  25         struct pid *pidptr;
  26         struct pid pid;
  27 };
  28
  29 #define pid_task(elem, type) \
  30         list_entry(elem, struct task_struct, pids[type].pid_chain)
  31
  32 /*
  33  * attach_pid() and link_pid() must be called with the tasklist_lock
  34  * write-held.
  35  */
  36 extern int FASTCALL(attach_pid(struct task_struct *task, enum pid_type type, int nr));
  37
  38 extern void FASTCALL(link_pid(struct task_struct *task, struct pid_link *link, struct pid *pid));
  39
  40 /*
  41  * detach_pid() must be called with the tasklist_lock write-held.
  42  */
  43 extern void FASTCALL(detach_pid(struct task_struct *task, enum pid_type));
  44
  45 /*
  46  * look up a PID in the hash table. Must be called with the tasklist_lock
  47  * held.
  48  */
  49 extern struct pid *FASTCALL(find_pid(enum pid_type, int));
  50
  51 extern int alloc_pidmap(void);
  52 extern void FASTCALL(free_pidmap(int));
  53 extern void switch_exec_pids(struct task_struct *leader, struct task_struct *thread);
  54
  55 #define for_each_task_pid(who, type, task, elem, pid)           \
  56         if ((pid = find_pid(type, who)))                        \
  57                 for (elem = pid->task_list.next,                        \
  58                         prefetch(elem->next),                           \
  59                         task = pid_task(elem, type);                    \
  60                         elem != &pid->task_list;                        \
  61                         elem = elem->next, prefetch(elem->next),        \
  62                         task = pid_task(elem, type))
  63
  64 #endif /* _LINUX_PID_H */