/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PID_NS_H
#define _LINUX_PID_NS_H

#include <linux/sched.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
#include <linux/threads.h>
#include <linux/nsproxy.h>
#include <linux/ns_common.h>
#include <linux/idr.h>

/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
#define MAX_PID_NS_LEVEL 32

struct fs_pin;

#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
/* modes for vm.memfd_noexec sysctl */
#define MEMFD_NOEXEC_SCOPE_EXEC                 0 /* MFD_EXEC implied if unset */
#define MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL          1 /* MFD_NOEXEC_SEAL implied if unset */
#define MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED      2 /* same as 1, except MFD_EXEC rejected */
#endif

struct pid_namespace {
        struct idr idr;
        struct rcu_head rcu;
        unsigned int pid_allocated;
#ifdef CONFIG_SYSCTL
#if defined(CONFIG_MEMFD_CREATE)
        int memfd_noexec_scope;
#endif
        struct ctl_table_set    set;
        struct ctl_table_header *sysctls;
#endif
        struct task_struct *child_reaper;
        struct kmem_cache *pid_cachep;
        unsigned int level;
        int pid_max;
        struct pid_namespace *parent;
#ifdef CONFIG_BSD_PROCESS_ACCT
        struct fs_pin *bacct;
#endif
        struct user_namespace *user_ns;
        struct ucounts *ucounts;
        int reboot;     /* group exit code if this pidns was rebooted */
        struct ns_common ns;
        struct work_struct      work;
} __randomize_layout;

extern struct pid_namespace init_pid_ns;

#define PIDNS_ADDING (1U << 31)

#ifdef CONFIG_PID_NS
static inline struct pid_namespace *to_pid_ns(struct ns_common *ns)
{
        return container_of(ns, struct pid_namespace, ns);
}

static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
{
        ns_ref_inc(ns);
        return ns;
}

#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
{
        int scope = MEMFD_NOEXEC_SCOPE_EXEC;

        for (; ns; ns = ns->parent)
                scope = max(scope, READ_ONCE(ns->memfd_noexec_scope));

        return scope;
}
#else
static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
{
        return 0;
}
#endif

extern struct pid_namespace *copy_pid_ns(u64 flags,
        struct user_namespace *user_ns, struct pid_namespace *ns);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
extern void put_pid_ns(struct pid_namespace *ns);

extern bool pidns_is_ancestor(struct pid_namespace *child,
                              struct pid_namespace *ancestor);

#else /* !CONFIG_PID_NS */
#include <linux/err.h>

static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
{
        return ns;
}

static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns)
{
        return 0;
}

static inline struct pid_namespace *copy_pid_ns(u64 flags,
        struct user_namespace *user_ns, struct pid_namespace *ns)
{
        if (flags & CLONE_NEWPID)
                ns = ERR_PTR(-EINVAL);
        return ns;
}

static inline void put_pid_ns(struct pid_namespace *ns)
{
}

static inline void zap_pid_ns_processes(struct pid_namespace *ns)
{
        BUG();
}

static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
{
        return 0;
}

static inline bool pidns_is_ancestor(struct pid_namespace *child,
                                     struct pid_namespace *ancestor)
{
        return false;
}
#endif /* CONFIG_PID_NS */

extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
void pidhash_init(void);
void pid_idr_init(void);
int register_pidns_sysctls(struct pid_namespace *pidns);
void unregister_pidns_sysctls(struct pid_namespace *pidns);

static inline bool task_is_in_init_pid_ns(struct task_struct *tsk)
{
        return task_active_pid_ns(tsk) == &init_pid_ns;
}

#endif /* _LINUX_PID_NS_H */