diff options
Diffstat (limited to 'include/linux/pid.h')
| -rw-r--r-- | include/linux/pid.h | 200 |
1 files changed, 169 insertions, 31 deletions
diff --git a/include/linux/pid.h b/include/linux/pid.h index 23705a53abba..003a1027d219 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -1,15 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_PID_H #define _LINUX_PID_H +#include <linux/pid_types.h> +#include <linux/rculist.h> #include <linux/rcupdate.h> - -enum pid_type -{ - PIDTYPE_PID, - PIDTYPE_PGID, - PIDTYPE_SID, - PIDTYPE_MAX -}; +#include <linux/refcount.h> +#include <linux/sched.h> +#include <linux/wait.h> /* * What is struct pid? @@ -47,40 +45,58 @@ enum pid_type * find_pid_ns() using the int nr and struct pid_namespace *ns. */ +#define RESERVED_PIDS 300 + +struct pidfs_attr; + struct upid { - /* Try to keep pid_chain in the same cacheline as nr for find_vpid */ int nr; struct pid_namespace *ns; - struct hlist_node pid_chain; }; -struct pid -{ - atomic_t count; +struct pid { + refcount_t count; unsigned int level; + spinlock_t lock; + struct { + u64 ino; + struct rb_node pidfs_node; + struct dentry *stashed; + struct pidfs_attr *attr; + }; /* lists of tasks that use this pid */ struct hlist_head tasks[PIDTYPE_MAX]; + struct hlist_head inodes; + /* wait queue for pidfd notifications */ + wait_queue_head_t wait_pidfd; struct rcu_head rcu; - struct upid numbers[1]; + struct upid numbers[]; }; +extern seqcount_spinlock_t pidmap_lock_seq; extern struct pid init_struct_pid; -struct pid_link -{ - struct hlist_node node; - struct pid *pid; -}; +struct file; + +struct pid *pidfd_pid(const struct file *file); +struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags); +struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags); +int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret_file); +void do_notify_pidfd(struct task_struct *task); static inline struct pid *get_pid(struct pid *pid) { if (pid) - atomic_inc(&pid->count); + refcount_inc(&pid->count); return pid; } extern void put_pid(struct pid *pid); extern struct task_struct *pid_task(struct pid *pid, enum pid_type); +static inline bool pid_has_task(struct pid *pid, enum pid_type type) +{ + return !hlist_empty(&pid->tasks[type]); +} extern struct task_struct *get_pid_task(struct pid *pid, enum pid_type); extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type); @@ -89,15 +105,13 @@ extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type); * these helpers must be called with the tasklist_lock write-held. */ extern void attach_pid(struct task_struct *task, enum pid_type); -extern void detach_pid(struct task_struct *task, enum pid_type); -extern void change_pid(struct task_struct *task, enum pid_type, - struct pid *pid); +void detach_pid(struct pid **pids, struct task_struct *task, enum pid_type); +void change_pid(struct pid **pids, struct task_struct *task, enum pid_type, + struct pid *pid); +extern void exchange_tids(struct task_struct *task, struct task_struct *old); extern void transfer_pid(struct task_struct *old, struct task_struct *new, enum pid_type); -struct pid_namespace; -extern struct pid_namespace init_pid_ns; - /* * look up a PID in the hash table. Must be called with the tasklist_lock * or rcu_read_lock() held. @@ -115,10 +129,11 @@ extern struct pid *find_vpid(int nr); */ extern struct pid *find_get_pid(int nr); extern struct pid *find_ge_pid(int nr, struct pid_namespace *); -int next_pidmap(struct pid_namespace *pid_ns, unsigned int last); -extern struct pid *alloc_pid(struct pid_namespace *ns); +extern struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid, + size_t set_tid_size); extern void free_pid(struct pid *pid); +void free_pids(struct pid **pids); extern void disable_pid_allocation(struct pid_namespace *ns); /* @@ -176,7 +191,7 @@ pid_t pid_vnr(struct pid *pid); do { \ if ((pid) != NULL) \ hlist_for_each_entry_rcu((task), \ - &(pid)->tasks[type], pids[type].node) { + &(pid)->tasks[type], pid_links[type]) { /* * Both old and new leaders may be attached to @@ -191,10 +206,133 @@ pid_t pid_vnr(struct pid *pid); #define do_each_pid_thread(pid, type, task) \ do_each_pid_task(pid, type, task) { \ struct task_struct *tg___ = task; \ - do { + for_each_thread(tg___, task) { #define while_each_pid_thread(pid, type, task) \ - } while_each_thread(tg___, task); \ + } \ task = tg___; \ } while_each_pid_task(pid, type, task) + +static inline struct pid *task_pid(struct task_struct *task) +{ + return task->thread_pid; +} + +/* + * the helpers to get the task's different pids as they are seen + * from various namespaces + * + * task_xid_nr() : global id, i.e. the id seen from the init namespace; + * task_xid_vnr() : virtual id, i.e. the id seen from the pid namespace of + * current. + * task_xid_nr_ns() : id seen from the ns specified; + * + * see also pid_nr() etc in include/linux/pid.h + */ +pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, struct pid_namespace *ns); + +static inline pid_t task_pid_nr(struct task_struct *tsk) +{ + return tsk->pid; +} + +static inline pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_PID, ns); +} + +static inline pid_t task_pid_vnr(struct task_struct *tsk) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_PID, NULL); +} + + +static inline pid_t task_tgid_nr(struct task_struct *tsk) +{ + return tsk->tgid; +} + +/** + * pid_alive - check that a task structure is not stale + * @p: Task structure to be checked. + * + * Test if a process is not yet dead (at most zombie state) + * If pid_alive fails, then pointers within the task structure + * can be stale and must not be dereferenced. + * + * Return: 1 if the process is alive. 0 otherwise. + */ +static inline int pid_alive(const struct task_struct *p) +{ + return p->thread_pid != NULL; +} + +static inline pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_PGID, ns); +} + +static inline pid_t task_pgrp_vnr(struct task_struct *tsk) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_PGID, NULL); +} + + +static inline pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_SID, ns); +} + +static inline pid_t task_session_vnr(struct task_struct *tsk) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_SID, NULL); +} + +static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_TGID, ns); +} + +static inline pid_t task_tgid_vnr(struct task_struct *tsk) +{ + return __task_pid_nr_ns(tsk, PIDTYPE_TGID, NULL); +} + +static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns) +{ + pid_t pid = 0; + + rcu_read_lock(); + if (pid_alive(tsk)) + pid = task_tgid_nr_ns(rcu_dereference(tsk->real_parent), ns); + rcu_read_unlock(); + + return pid; +} + +static inline pid_t task_ppid_nr(const struct task_struct *tsk) +{ + return task_ppid_nr_ns(tsk, &init_pid_ns); +} + +/* Obsolete, do not use: */ +static inline pid_t task_pgrp_nr(struct task_struct *tsk) +{ + return task_pgrp_nr_ns(tsk, &init_pid_ns); +} + +/** + * is_global_init - check if a task structure is init. Since init + * is free to have sub-threads we need to check tgid. + * @tsk: Task structure to be checked. + * + * Check if a task structure is the first user space task the kernel created. + * + * Return: 1 if the task structure is init. 0 otherwise. + */ +static inline int is_global_init(struct task_struct *tsk) +{ + return task_tgid_nr(tsk) == 1; +} + #endif /* _LINUX_PID_H */ |