ipc/mq_sysctl.c

Source file repositories/reference/linux-study-clean/ipc/mq_sysctl.c

File Facts

System
Linux kernel
Corpus path
ipc/mq_sysctl.c
Extension
.c
Size
3994 bytes
Lines
168
Domain
Core OS
Bucket
IPC
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2007 IBM Corporation
 *
 *  Author: Cedric Le Goater <clg@fr.ibm.com>
 */

#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>

#include <linux/stat.h>
#include <linux/capability.h>
#include <linux/slab.h>
#include <linux/cred.h>

static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;

static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;

static const struct ctl_table mq_sysctls[] = {
	{
		.procname	= "queues_max",
		.data		= &init_ipc_ns.mq_queues_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
	},
	{
		.procname	= "msg_max",
		.data		= &init_ipc_ns.mq_msg_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &msg_max_limit_min,
		.extra2		= &msg_max_limit_max,
	},
	{
		.procname	= "msgsize_max",
		.data		= &init_ipc_ns.mq_msgsize_max,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &msg_maxsize_limit_min,
		.extra2		= &msg_maxsize_limit_max,
	},
	{
		.procname	= "msg_default",
		.data		= &init_ipc_ns.mq_msg_default,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &msg_max_limit_min,
		.extra2		= &msg_max_limit_max,
	},
	{
		.procname	= "msgsize_default",
		.data		= &init_ipc_ns.mq_msgsize_default,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &msg_maxsize_limit_min,
		.extra2		= &msg_maxsize_limit_max,
	},
};

static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
{
	return &current->nsproxy->ipc_ns->mq_set;
}

static int set_is_seen(struct ctl_table_set *set)
{
	return &current->nsproxy->ipc_ns->mq_set == set;
}

static void mq_set_ownership(struct ctl_table_header *head,
			     kuid_t *uid, kgid_t *gid)
{
	struct ipc_namespace *ns =
		container_of(head->set, struct ipc_namespace, mq_set);

	kuid_t ns_root_uid = make_kuid(ns->user_ns, 0);
	kgid_t ns_root_gid = make_kgid(ns->user_ns, 0);

	*uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID;
	*gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID;
}

Annotation

Implementation Notes