| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/ipc/util.c |
| * Copyright (C) 1992 Krishna Balasubramanian |
| * |
| * Sep 1997 - Call suser() last after "normal" permission checks so we |
| * get BSD style process accounting right. |
| * Occurs in several places in the IPC code. |
| * Chris Evans, <chris@ferret.lmh.ox.ac.uk> |
| * Nov 1999 - ipc helper functions, unified SMP locking |
| * Manfred Spraul <manfred@colorfullife.com> |
| * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). |
| * Mingming Cao <cmm@us.ibm.com> |
| * Mar 2006 - support for audit of ipc object properties |
| * Dustin Kirkland <dustin.kirkland@us.ibm.com> |
| * Jun 2006 - namespaces ssupport |
| * OpenVZ, SWsoft Inc. |
| * Pavel Emelianov <xemul@openvz.org> |
| * |
| * General sysv ipc locking scheme: |
| * rcu_read_lock() |
| * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr |
| * tree. |
| * - perform initial checks (capabilities, auditing and permission, |
| * etc). |
| * - perform read-only operations, such as INFO command, that |
| * do not demand atomicity |
| * acquire the ipc lock (kern_ipc_perm.lock) through |
| * ipc_lock_object() |
| * - perform read-only operations that demand atomicity, |
| * such as STAT command. |
| * - perform data updates, such as SET, RMID commands and |
| * mechanism-specific operations (semop/semtimedop, |
| * msgsnd/msgrcv, shmat/shmdt). |
| * drop the ipc lock, through ipc_unlock_object(). |
| * rcu_read_unlock() |
| * |
| * The ids->rwsem must be taken when: |
| * - creating, removing and iterating the existing entries in ipc |
| * identifier sets. |
| * - iterating through files under /proc/sysvipc/ |
| * |
| * Note that sems have a special fast path that avoids kern_ipc_perm.lock - |
| * see sem_lock(). |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/shm.h> |
| #include <linux/init.h> |
| #include <linux/msg.h> |
| #include <linux/vmalloc.h> |
| #include <linux/slab.h> |
| #include <linux/notifier.h> |
| #include <linux/capability.h> |
| #include <linux/highuid.h> |
| #include <linux/security.h> |
| #include <linux/rcupdate.h> |
| #include <linux/workqueue.h> |
| #include <linux/seq_file.h> |
| #include <linux/proc_fs.h> |
| #include <linux/audit.h> |
| #include <linux/nsproxy.h> |
| #include <linux/rwsem.h> |
| #include <linux/memory.h> |
| #include <linux/ipc_namespace.h> |
| #include <linux/rhashtable.h> |
| |
| #include <asm/unistd.h> |
| |
| #include "util.h" |
| |
| struct ipc_proc_iface { |
| const char *path; |
| const char *header; |
| int ids; |
| int (*show)(struct seq_file *, void *); |
| }; |
| |
| /** |
| * ipc_init - initialise ipc subsystem |
| * |
| * The various sysv ipc resources (semaphores, messages and shared |
| * memory) are initialised. |
| * |
| * A callback routine is registered into the memory hotplug notifier |
| * chain: since msgmni scales to lowmem this callback routine will be |
| * called upon successful memory add / remove to recompute msmgni. |
| */ |
| static int __init ipc_init(void) |
| { |
| proc_mkdir("sysvipc", NULL); |
| sem_init(); |
| msg_init(); |
| shm_init(); |
| |
| return 0; |
| } |
| device_initcall(ipc_init); |
| |
| static const struct rhashtable_params ipc_kht_params = { |
| .head_offset = offsetof(struct kern_ipc_perm, khtnode), |
| .key_offset = offsetof(struct kern_ipc_perm, key), |
| .key_len = FIELD_SIZEOF(struct kern_ipc_perm, key), |
| .locks_mul = 1, |
| .automatic_shrinking = true, |
| }; |
| |
| /** |
| * ipc_init_ids - initialise ipc identifiers |
| * @ids: ipc identifier set |
| * |
| * Set up the sequence range to use for the ipc identifier range (limited |
| * below IPCMNI) then initialise the keys hashtable and ids idr. |
| */ |
| void ipc_init_ids(struct ipc_ids *ids) |
| { |
| ids->in_use = 0; |
| ids->seq = 0; |
| init_rwsem(&ids->rwsem); |
| rhashtable_init(&ids->key_ht, &ipc_kht_params); |
| idr_init(&ids->ipcs_idr); |
| ids->max_idx = -1; |
| #ifdef CONFIG_CHECKPOINT_RESTORE |
| ids->next_id = -1; |
| #endif |
| } |
| |
| #ifdef CONFIG_PROC_FS |
| static const struct file_operations sysvipc_proc_fops; |
| /** |
| * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. |
| * @path: Path in procfs |
| * @header: Banner to be printed at the beginning of the file. |
| * @ids: ipc id table to iterate. |
| * @show: show routine. |
| */ |
| void __init ipc_init_proc_interface(const char *path, const char *header, |
| int ids, int (*show)(struct seq_file *, void *)) |
| { |
| struct proc_dir_entry *pde; |
| struct ipc_proc_iface *iface; |
| |
| iface = kmalloc(sizeof(*iface), GFP_KERNEL); |
| if (!iface) |
| return; |
| iface->path = path; |
| iface->header = header; |
| iface->ids = ids; |
| iface->show = show; |
| |
| pde = proc_create_data(path, |
| S_IRUGO, /* world readable */ |
| NULL, /* parent dir */ |
| &sysvipc_proc_fops, |
| iface); |
| if (!pde) |
| kfree(iface); |
| } |
| #endif |
| |
| /** |
| * ipc_findkey - find a key in an ipc identifier set |
| * @ids: ipc identifier set |
| * @key: key to find |
| * |
| * Returns the locked pointer to the ipc structure if found or NULL |
| * otherwise. If key is found ipc points to the owning ipc structure |
| * |
| * Called with writer ipc_ids.rwsem held. |
| */ |
| static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
| { |
| struct kern_ipc_perm *ipcp; |
| |
| ipcp = rhashtable_lookup_fast(&ids->key_ht, &key, |
| ipc_kht_params); |
| if (!ipcp) |
| return NULL; |
| |
| rcu_read_lock(); |
| ipc_lock_object(ipcp); |
| return ipcp; |
| } |
| |
| /* |
| * Insert new IPC object into idr tree, and set sequence number and id |
| * in the correct order. |
| * Especially: |
| * - the sequence number must be set before inserting the object into the idr, |
| * because the sequence number is accessed without a lock. |
| * - the id can/must be set after inserting the object into the idr. |
| * All accesses must be done after getting kern_ipc_perm.lock. |
| * |
| * The caller must own kern_ipc_perm.lock.of the new object. |
| * On error, the function returns a (negative) error code. |
| */ |
| static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new) |
| { |
| int idx, next_id = -1; |
| |
| #ifdef CONFIG_CHECKPOINT_RESTORE |
| next_id = ids->next_id; |
| ids->next_id = -1; |
| #endif |
| |
| /* |
| * As soon as a new object is inserted into the idr, |
| * ipc_obtain_object_idr() or ipc_obtain_object_check() can find it, |
| * and the lockless preparations for ipc operations can start. |
| * This means especially: permission checks, audit calls, allocation |
| * of undo structures, ... |
| * |
| * Thus the object must be fully initialized, and if something fails, |
| * then the full tear-down sequence must be followed. |
| * (i.e.: set new->deleted, reduce refcount, call_rcu()) |
| */ |
| |
| if (next_id < 0) { /* !CHECKPOINT_RESTORE or next_id is unset */ |
| new->seq = ids->seq++; |
| if (ids->seq > IPCID_SEQ_MAX) |
| ids->seq = 0; |
| idx = idr_alloc(&ids->ipcs_idr, new, 0, 0, GFP_NOWAIT); |
| } else { |
| new->seq = ipcid_to_seqx(next_id); |
| idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id), |
| 0, GFP_NOWAIT); |
| } |
| if (idx >= 0) |
| new->id = SEQ_MULTIPLIER * new->seq + idx; |
| return idx; |
| } |
| |
| /** |
| * ipc_addid - add an ipc identifier |
| * @ids: ipc identifier set |
| * @new: new ipc permission set |
| * @limit: limit for the number of used ids |
| * |
| * Add an entry 'new' to the ipc ids idr. The permissions object is |
| * initialised and the first free entry is set up and the index assigned |
| * is returned. The 'new' entry is returned in a locked state on success. |
| * |
| * On failure the entry is not locked and a negative err-code is returned. |
| * The caller must use ipc_rcu_putref() to free the identifier. |
| * |
| * Called with writer ipc_ids.rwsem held. |
| */ |
| int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit) |
| { |
| kuid_t euid; |
| kgid_t egid; |
| int idx, err; |
| |
| /* 1) Initialize the refcount so that ipc_rcu_putref works */ |
| refcount_set(&new->refcount, 1); |
| |
| if (limit > IPCMNI) |
| limit = IPCMNI; |
| |
| if (ids->in_use >= limit) |
| return -ENOSPC; |
| |
| idr_preload(GFP_KERNEL); |
| |
| spin_lock_init(&new->lock); |
| rcu_read_lock(); |
| spin_lock(&new->lock); |
| |
| current_euid_egid(&euid, &egid); |
| new->cuid = new->uid = euid; |
| new->gid = new->cgid = egid; |
| |
| new->deleted = false; |
| |
| idx = ipc_idr_alloc(ids, new); |
| idr_preload_end(); |
| |
| if (idx >= 0 && new->key != IPC_PRIVATE) { |
| err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode, |
| ipc_kht_params); |
| if (err < 0) { |
| idr_remove(&ids->ipcs_idr, idx); |
| idx = err; |
| } |
| } |
| if (idx < 0) { |
| new->deleted = true; |
| spin_unlock(&new->lock); |
| rcu_read_unlock(); |
| return idx; |
| } |
| |
| ids->in_use++; |
| if (idx > ids->max_idx) |
| ids->max_idx = idx; |
| return idx; |
| } |
| |
| /** |
| * ipcget_new - create a new ipc object |
| * @ns: ipc namespace |
| * @ids: ipc identifier set |
| * @ops: the actual creation routine to call |
| * @params: its parameters |
| * |
| * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
| * when the key is IPC_PRIVATE. |
| */ |
| static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
| const struct ipc_ops *ops, struct ipc_params *params) |
| { |
| int err; |
| |
| down_write(&ids->rwsem); |
| err = ops->getnew(ns, params); |
| up_write(&ids->rwsem); |
| return err; |
| } |
| |
| /** |
| * ipc_check_perms - check security and permissions for an ipc object |
| * @ns: ipc namespace |
| * @ipcp: ipc permission set |
| * @ops: the actual security routine to call |
| * @params: its parameters |
| * |
| * This routine is called by sys_msgget(), sys_semget() and sys_shmget() |
| * when the key is not IPC_PRIVATE and that key already exists in the |
| * ds IDR. |
| * |
| * On success, the ipc id is returned. |
| * |
| * It is called with ipc_ids.rwsem and ipcp->lock held. |
| */ |
| static int ipc_check_perms(struct ipc_namespace *ns, |
| struct kern_ipc_perm *ipcp, |
| const struct ipc_ops *ops, |
| struct ipc_params *params) |
| { |
| int err; |
| |
| if (ipcperms(ns, ipcp, params->flg)) |
| err = -EACCES; |
| else { |
| err = ops->associate(ipcp, params->flg); |
| if (!err) |
| err = ipcp->id; |
| } |
| |
| return err; |
| } |
| |
| /** |
| * ipcget_public - get an ipc object or create a new one |
| * @ns: ipc namespace |
| * @ids: ipc identifier set |
| * @ops: the actual creation routine to call |
| * @params: its parameters |
| * |
| * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
| * when the key is not IPC_PRIVATE. |
| * It adds a new entry if the key is not found and does some permission |
| * / security checkings if the key is found. |
| * |
| * On success, the ipc id is returned. |
| */ |
| static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
| const struct ipc_ops *ops, struct ipc_params *params) |
| { |
| struct kern_ipc_perm *ipcp; |
| int flg = params->flg; |
| int err; |
| |
| /* |
| * Take the lock as a writer since we are potentially going to add |
| * a new entry + read locks are not "upgradable" |
| */ |
| down_write(&ids->rwsem); |
| ipcp = ipc_findkey(ids, params->key); |
| if (ipcp == NULL) { |
| /* key not used */ |
| if (!(flg & IPC_CREAT)) |
| err = -ENOENT; |
| else |
| err = ops->getnew(ns, params); |
| } else { |
| /* ipc object has been locked by ipc_findkey() */ |
| |
| if (flg & IPC_CREAT && flg & IPC_EXCL) |
| err = -EEXIST; |
| else { |
| err = 0; |
| if (ops->more_checks) |
| err = ops->more_checks(ipcp, params); |
| if (!err) |
| /* |
| * ipc_check_perms returns the IPC id on |
| * success |
| */ |
| err = ipc_check_perms(ns, ipcp, ops, params); |
| } |
| ipc_unlock(ipcp); |
| } |
| up_write(&ids->rwsem); |
| |
| return err; |
| } |
| |
| /** |
| * ipc_kht_remove - remove an ipc from the key hashtable |
| * @ids: ipc identifier set |
| * @ipcp: ipc perm structure containing the key to remove |
| * |
| * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
| * before this function is called, and remain locked on the exit. |
| */ |
| static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
| { |
| if (ipcp->key != IPC_PRIVATE) |
| rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode, |
| ipc_kht_params); |
| } |
| |
| /** |
| * ipc_rmid - remove an ipc identifier |
| * @ids: ipc identifier set |
| * @ipcp: ipc perm structure containing the identifier to remove |
| * |
| * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
| * before this function is called, and remain locked on the exit. |
| */ |
| void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
| { |
| int idx = ipcid_to_idx(ipcp->id); |
| |
| idr_remove(&ids->ipcs_idr, idx); |
| ipc_kht_remove(ids, ipcp); |
| ids->in_use--; |
| ipcp->deleted = true; |
| |
| if (unlikely(idx == ids->max_idx)) { |
| do { |
| idx--; |
| if (idx == -1) |
| break; |
| } while (!idr_find(&ids->ipcs_idr, idx)); |
| ids->max_idx = idx; |
| } |
| } |
| |
| /** |
| * ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE |
| * @ids: ipc identifier set |
| * @ipcp: ipc perm structure containing the key to modify |
| * |
| * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
| * before this function is called, and remain locked on the exit. |
| */ |
| void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
| { |
| ipc_kht_remove(ids, ipcp); |
| ipcp->key = IPC_PRIVATE; |
| } |
| |
| bool ipc_rcu_getref(struct kern_ipc_perm *ptr) |
| { |
| return refcount_inc_not_zero(&ptr->refcount); |
| } |
| |
| void ipc_rcu_putref(struct kern_ipc_perm *ptr, |
| void (*func)(struct rcu_head *head)) |
| { |
| if (!refcount_dec_and_test(&ptr->refcount)) |
| return; |
| |
| call_rcu(&ptr->rcu, func); |
| } |
| |
| /** |
| * ipcperms - check ipc permissions |
| * @ns: ipc namespace |
| * @ipcp: ipc permission set |
| * @flag: desired permission set |
| * |
| * Check user, group, other permissions for access |
| * to ipc resources. return 0 if allowed |
| * |
| * @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h> |
| */ |
| int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
| { |
| kuid_t euid = current_euid(); |
| int requested_mode, granted_mode; |
| |
| audit_ipc_obj(ipcp); |
| requested_mode = (flag >> 6) | (flag >> 3) | flag; |
| granted_mode = ipcp->mode; |
| if (uid_eq(euid, ipcp->cuid) || |
| uid_eq(euid, ipcp->uid)) |
| granted_mode >>= 6; |
| else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) |
| granted_mode >>= 3; |
| /* is there some bit set in requested_mode but not in granted_mode? */ |
| if ((requested_mode & ~granted_mode & 0007) && |
| !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
| return -1; |
| |
| return security_ipc_permission(ipcp, flag); |
| } |
| |
| /* |
| * Functions to convert between the kern_ipc_perm structure and the |
| * old/new ipc_perm structures |
| */ |
| |
| /** |
| * kernel_to_ipc64_perm - convert kernel ipc permissions to user |
| * @in: kernel permissions |
| * @out: new style ipc permissions |
| * |
| * Turn the kernel object @in into a set of permissions descriptions |
| * for returning to userspace (@out). |
| */ |
| void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) |
| { |
| out->key = in->key; |
| out->uid = from_kuid_munged(current_user_ns(), in->uid); |
| out->gid = from_kgid_munged(current_user_ns(), in->gid); |
| out->cuid = from_kuid_munged(current_user_ns(), in->cuid); |
| out->cgid = from_kgid_munged(current_user_ns(), in->cgid); |
| out->mode = in->mode; |
| out->seq = in->seq; |
| } |
| |
| /** |
| * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
| * @in: new style ipc permissions |
| * @out: old style ipc permissions |
| * |
| * Turn the new style permissions object @in into a compatibility |
| * object and store it into the @out pointer. |
| */ |
| void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) |
| { |
| out->key = in->key; |
| SET_UID(out->uid, in->uid); |
| SET_GID(out->gid, in->gid); |
| SET_UID(out->cuid, in->cuid); |
| SET_GID(out->cgid, in->cgid); |
| out->mode = in->mode; |
| out->seq = in->seq; |
| } |
| |
| /** |
| * ipc_obtain_object_idr |
| * @ids: ipc identifier set |
| * @id: ipc id to look for |
| * |
| * Look for an id in the ipc ids idr and return associated ipc object. |
| * |
| * Call inside the RCU critical section. |
| * The ipc object is *not* locked on exit. |
| */ |
| struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id) |
| { |
| struct kern_ipc_perm *out; |
| int idx = ipcid_to_idx(id); |
| |
| out = idr_find(&ids->ipcs_idr, idx); |
| if (!out) |
| return ERR_PTR(-EINVAL); |
| |
| return out; |
| } |
| |
| /** |
| * ipc_obtain_object_check |
| * @ids: ipc identifier set |
| * @id: ipc id to look for |
| * |
| * Similar to ipc_obtain_object_idr() but also checks the ipc object |
| * sequence number. |
| * |
| * Call inside the RCU critical section. |
| * The ipc object is *not* locked on exit. |
| */ |
| struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) |
| { |
| struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id); |
| |
| if (IS_ERR(out)) |
| goto out; |
| |
| if (ipc_checkid(out, id)) |
| return ERR_PTR(-EINVAL); |
| out: |
| return out; |
| } |
| |
| /** |
| * ipcget - Common sys_*get() code |
| * @ns: namespace |
| * @ids: ipc identifier set |
| * @ops: operations to be called on ipc object creation, permission checks |
| * and further checks |
| * @params: the parameters needed by the previous operations. |
| * |
| * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). |
| */ |
| int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, |
| const struct ipc_ops *ops, struct ipc_params *params) |
| { |
| if (params->key == IPC_PRIVATE) |
| return ipcget_new(ns, ids, ops, params); |
| else |
| return ipcget_public(ns, ids, ops, params); |
| } |
| |
| /** |
| * ipc_update_perm - update the permissions of an ipc object |
| * @in: the permission given as input. |
| * @out: the permission of the ipc to set. |
| */ |
| int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
| { |
| kuid_t uid = make_kuid(current_user_ns(), in->uid); |
| kgid_t gid = make_kgid(current_user_ns(), in->gid); |
| if (!uid_valid(uid) || !gid_valid(gid)) |
| return -EINVAL; |
| |
| out->uid = uid; |
| out->gid = gid; |
| out->mode = (out->mode & ~S_IRWXUGO) |
| | (in->mode & S_IRWXUGO); |
| |
| return 0; |
| } |
| |
| /** |
| * ipcctl_obtain_check - retrieve an ipc object and check permissions |
| * @ns: ipc namespace |
| * @ids: the table of ids where to look for the ipc |
| * @id: the id of the ipc to retrieve |
| * @cmd: the cmd to check |
| * @perm: the permission to set |
| * @extra_perm: one extra permission parameter used by msq |
| * |
| * This function does some common audit and permissions check for some IPC_XXX |
| * cmd and is called from semctl_down, shmctl_down and msgctl_down. |
| * |
| * It: |
| * - retrieves the ipc object with the given id in the given table. |
| * - performs some audit and permission check, depending on the given cmd |
| * - returns a pointer to the ipc object or otherwise, the corresponding |
| * error. |
| * |
| * Call holding the both the rwsem and the rcu read lock. |
| */ |
| struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns, |
| struct ipc_ids *ids, int id, int cmd, |
| struct ipc64_perm *perm, int extra_perm) |
| { |
| kuid_t euid; |
| int err = -EPERM; |
| struct kern_ipc_perm *ipcp; |
| |
| ipcp = ipc_obtain_object_check(ids, id); |
| if (IS_ERR(ipcp)) { |
| err = PTR_ERR(ipcp); |
| goto err; |
| } |
| |
| audit_ipc_obj(ipcp); |
| if (cmd == IPC_SET) |
| audit_ipc_set_perm(extra_perm, perm->uid, |
| perm->gid, perm->mode); |
| |
| euid = current_euid(); |
| if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
| ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
| return ipcp; /* successful lookup */ |
| err: |
| return ERR_PTR(err); |
| } |
| |
| #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
| |
| |
| /** |
| * ipc_parse_version - ipc call version |
| * @cmd: pointer to command |
| * |
| * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. |
| * The @cmd value is turned from an encoding command and version into |
| * just the command code. |
| */ |
| int ipc_parse_version(int *cmd) |
| { |
| if (*cmd & IPC_64) { |
| *cmd ^= IPC_64; |
| return IPC_64; |
| } else { |
| return IPC_OLD; |
| } |
| } |
| |
| #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
| |
| #ifdef CONFIG_PROC_FS |
| struct ipc_proc_iter { |
| struct ipc_namespace *ns; |
| struct pid_namespace *pid_ns; |
| struct ipc_proc_iface *iface; |
| }; |
| |
| struct pid_namespace *ipc_seq_pid_ns(struct seq_file *s) |
| { |
| struct ipc_proc_iter *iter = s->private; |
| return iter->pid_ns; |
| } |
| |
| /* |
| * This routine locks the ipc structure found at least at position pos. |
| */ |
| static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
| loff_t *new_pos) |
| { |
| struct kern_ipc_perm *ipc; |
| int total, id; |
| |
| total = 0; |
| for (id = 0; id < pos && total < ids->in_use; id++) { |
| ipc = idr_find(&ids->ipcs_idr, id); |
| if (ipc != NULL) |
| total++; |
| } |
| |
| if (total >= ids->in_use) |
| return NULL; |
| |
| for (; pos < IPCMNI; pos++) { |
| ipc = idr_find(&ids->ipcs_idr, pos); |
| if (ipc != NULL) { |
| *new_pos = pos + 1; |
| rcu_read_lock(); |
| ipc_lock_object(ipc); |
| return ipc; |
| } |
| } |
| |
| /* Out of range - return NULL to terminate iteration */ |
| return NULL; |
| } |
| |
| static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
| { |
| struct ipc_proc_iter *iter = s->private; |
| struct ipc_proc_iface *iface = iter->iface; |
| struct kern_ipc_perm *ipc = it; |
| |
| /* If we had an ipc id locked before, unlock it */ |
| if (ipc && ipc != SEQ_START_TOKEN) |
| ipc_unlock(ipc); |
| |
| return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
| } |
| |
| /* |
| * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
| * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. |
| */ |
| static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) |
| { |
| struct ipc_proc_iter *iter = s->private; |
| struct ipc_proc_iface *iface = iter->iface; |
| struct ipc_ids *ids; |
| |
| ids = &iter->ns->ids[iface->ids]; |
| |
| /* |
| * Take the lock - this will be released by the corresponding |
| * call to stop(). |
| */ |
| down_read(&ids->rwsem); |
| |
| /* pos < 0 is invalid */ |
| if (*pos < 0) |
| return NULL; |
| |
| /* pos == 0 means header */ |
| if (*pos == 0) |
| return SEQ_START_TOKEN; |
| |
| /* Find the (pos-1)th ipc */ |
| return sysvipc_find_ipc(ids, *pos - 1, pos); |
| } |
| |
| static void sysvipc_proc_stop(struct seq_file *s, void *it) |
| { |
| struct kern_ipc_perm *ipc = it; |
| struct ipc_proc_iter *iter = s->private; |
| struct ipc_proc_iface *iface = iter->iface; |
| struct ipc_ids *ids; |
| |
| /* If we had a locked structure, release it */ |
| if (ipc && ipc != SEQ_START_TOKEN) |
| ipc_unlock(ipc); |
| |
| ids = &iter->ns->ids[iface->ids]; |
| /* Release the lock we took in start() */ |
| up_read(&ids->rwsem); |
| } |
| |
| static int sysvipc_proc_show(struct seq_file *s, void *it) |
| { |
| struct ipc_proc_iter *iter = s->private; |
| struct ipc_proc_iface *iface = iter->iface; |
| |
| if (it == SEQ_START_TOKEN) { |
| seq_puts(s, iface->header); |
| return 0; |
| } |
| |
| return iface->show(s, it); |
| } |
| |
| static const struct seq_operations sysvipc_proc_seqops = { |
| .start = sysvipc_proc_start, |
| .stop = sysvipc_proc_stop, |
| .next = sysvipc_proc_next, |
| .show = sysvipc_proc_show, |
| }; |
| |
| static int sysvipc_proc_open(struct inode *inode, struct file *file) |
| { |
| struct ipc_proc_iter *iter; |
| |
| iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter)); |
| if (!iter) |
| return -ENOMEM; |
| |
| iter->iface = PDE_DATA(inode); |
| iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
| iter->pid_ns = get_pid_ns(task_active_pid_ns(current)); |
| |
| return 0; |
| } |
| |
| static int sysvipc_proc_release(struct inode *inode, struct file *file) |
| { |
| struct seq_file *seq = file->private_data; |
| struct ipc_proc_iter *iter = seq->private; |
| put_ipc_ns(iter->ns); |
| put_pid_ns(iter->pid_ns); |
| return seq_release_private(inode, file); |
| } |
| |
| static const struct file_operations sysvipc_proc_fops = { |
| .open = sysvipc_proc_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = sysvipc_proc_release, |
| }; |
| #endif /* CONFIG_PROC_FS */ |