| /* |
| * 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 <manfreds@colorfullife.com> |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/mm.h> |
| #include <linux/shm.h> |
| #include <linux/init.h> |
| #include <linux/msg.h> |
| #include <linux/smp_lock.h> |
| #include <linux/vmalloc.h> |
| #include <linux/slab.h> |
| #include <linux/highuid.h> |
| |
| #if defined(CONFIG_SYSVIPC) |
| |
| #include "util.h" |
| |
| /** |
| * ipc_init - initialise IPC subsystem |
| * |
| * The various system5 IPC resources (semaphores, messages and shared |
| * memory are initialised |
| */ |
| |
| void __init ipc_init (void) |
| { |
| sem_init(); |
| msg_init(); |
| shm_init(); |
| return; |
| } |
| |
| /** |
| * ipc_init_ids - initialise IPC identifiers |
| * @ids: Identifier set |
| * @size: Number of identifiers |
| * |
| * Given a size for the ipc identifier range (limited below IPCMNI) |
| * set up the sequence range to use then allocate and initialise the |
| * array itself. |
| */ |
| |
| void __init ipc_init_ids(struct ipc_ids* ids, int size) |
| { |
| int i; |
| sema_init(&ids->sem,1); |
| |
| if(size > IPCMNI) |
| size = IPCMNI; |
| ids->size = size; |
| ids->in_use = 0; |
| ids->max_id = -1; |
| ids->seq = 0; |
| { |
| int seq_limit = INT_MAX/SEQ_MULTIPLIER; |
| if(seq_limit > USHRT_MAX) |
| ids->seq_max = USHRT_MAX; |
| else |
| ids->seq_max = seq_limit; |
| } |
| |
| ids->entries = ipc_alloc(sizeof(struct ipc_id)*size); |
| |
| if(ids->entries == NULL) { |
| printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n"); |
| ids->size = 0; |
| } |
| ids->ary = SPIN_LOCK_UNLOCKED; |
| for(i=0;i<ids->size;i++) |
| ids->entries[i].p = NULL; |
| } |
| |
| /** |
| * ipc_findkey - find a key in an ipc identifier set |
| * @ids: Identifier set |
| * @key: The key to find |
| * |
| * Returns the identifier if found or -1 if not. |
| */ |
| |
| int ipc_findkey(struct ipc_ids* ids, key_t key) |
| { |
| int id; |
| struct kern_ipc_perm* p; |
| |
| for (id = 0; id <= ids->max_id; id++) { |
| p = ids->entries[id].p; |
| if(p==NULL) |
| continue; |
| if (key == p->key) |
| return id; |
| } |
| return -1; |
| } |
| |
| static int grow_ary(struct ipc_ids* ids, int newsize) |
| { |
| struct ipc_id* new; |
| struct ipc_id* old; |
| int i; |
| |
| if(newsize > IPCMNI) |
| newsize = IPCMNI; |
| if(newsize <= ids->size) |
| return newsize; |
| |
| new = ipc_alloc(sizeof(struct ipc_id)*newsize); |
| if(new == NULL) |
| return ids->size; |
| memcpy(new, ids->entries, sizeof(struct ipc_id)*ids->size); |
| for(i=ids->size;i<newsize;i++) { |
| new[i].p = NULL; |
| } |
| spin_lock(&ids->ary); |
| |
| old = ids->entries; |
| ids->entries = new; |
| i = ids->size; |
| ids->size = newsize; |
| spin_unlock(&ids->ary); |
| ipc_free(old, sizeof(struct ipc_id)*i); |
| return ids->size; |
| } |
| |
| /** |
| * ipc_addid - add an IPC identifier |
| * @ids: IPC identifier set |
| * @new: new IPC permission set |
| * @size: new size limit for the id array |
| * |
| * Add an entry 'new' to the IPC arrays. The permissions object is |
| * initialised and the first free entry is set up and the id assigned |
| * is returned. The list is returned in a locked state on success. |
| * On failure the list is not locked and -1 is returned. |
| */ |
| |
| int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) |
| { |
| int id; |
| |
| size = grow_ary(ids,size); |
| for (id = 0; id < size; id++) { |
| if(ids->entries[id].p == NULL) |
| goto found; |
| } |
| return -1; |
| found: |
| ids->in_use++; |
| if (id > ids->max_id) |
| ids->max_id = id; |
| |
| new->cuid = new->uid = current->euid; |
| new->gid = new->cgid = current->egid; |
| |
| new->seq = ids->seq++; |
| if(ids->seq > ids->seq_max) |
| ids->seq = 0; |
| |
| spin_lock(&ids->ary); |
| ids->entries[id].p = new; |
| return id; |
| } |
| |
| /** |
| * ipc_rmid - remove an IPC identifier |
| * @ids: identifier set |
| * @id: Identifier to remove |
| * |
| * The identifier must be valid, and in use. The kernel will panic if |
| * fed an invalid identifier. The entry is removed and internal |
| * variables recomputed. The object associated with the identifier |
| * is returned. |
| */ |
| |
| struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id) |
| { |
| struct kern_ipc_perm* p; |
| int lid = id % SEQ_MULTIPLIER; |
| if(lid >= ids->size) |
| BUG(); |
| p = ids->entries[lid].p; |
| ids->entries[lid].p = NULL; |
| if(p==NULL) |
| BUG(); |
| ids->in_use--; |
| |
| if (lid == ids->max_id) { |
| do { |
| lid--; |
| if(lid == -1) |
| break; |
| } while (ids->entries[lid].p == NULL); |
| ids->max_id = lid; |
| } |
| return p; |
| } |
| |
| /** |
| * ipc_alloc - allocate ipc space |
| * @size: size desired |
| * |
| * Allocate memory from the appropriate pools and return a pointer to it. |
| * NULL is returned if the allocation fails |
| */ |
| |
| void* ipc_alloc(int size) |
| { |
| void* out; |
| if(size > PAGE_SIZE) |
| out = vmalloc(size); |
| else |
| out = kmalloc(size, GFP_KERNEL); |
| return out; |
| } |
| |
| /** |
| * ipc_free - free ipc space |
| * @ptr: pointer returned by ipc_alloc |
| * @size: size of block |
| * |
| * Free a block created with ipc_alloc. The caller must know the size |
| * used in the allocation call. |
| */ |
| |
| void ipc_free(void* ptr, int size) |
| { |
| if(size > PAGE_SIZE) |
| vfree(ptr); |
| else |
| kfree(ptr); |
| } |
| |
| /** |
| * ipcperms - check IPC permissions |
| * @ipcp: IPC permission set |
| * @flag: desired permission set. |
| * |
| * Check user, group, other permissions for access |
| * to ipc resources. return 0 if allowed |
| */ |
| |
| int ipcperms (struct kern_ipc_perm *ipcp, short flag) |
| { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ |
| int requested_mode, granted_mode; |
| |
| requested_mode = (flag >> 6) | (flag >> 3) | flag; |
| granted_mode = ipcp->mode; |
| if (current->euid == ipcp->cuid || current->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) && |
| !capable(CAP_IPC_OWNER)) |
| return -1; |
| |
| return 0; |
| } |
| |
| /* |
| * 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 = in->uid; |
| out->gid = in->gid; |
| out->cuid = in->cuid; |
| out->cgid = in->cgid; |
| out->mode = in->mode; |
| out->seq = in->seq; |
| } |
| |
| /** |
| * ipc64_perm_to_ipc_perm - convert old ipc permissions to new |
| * @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; |
| out->uid = NEW_TO_OLD_UID(in->uid); |
| out->gid = NEW_TO_OLD_GID(in->gid); |
| out->cuid = NEW_TO_OLD_UID(in->cuid); |
| out->cgid = NEW_TO_OLD_GID(in->cgid); |
| out->mode = in->mode; |
| out->seq = in->seq; |
| } |
| |
| #if !defined(__ia64__) && !defined(__hppa__) |
| |
| /** |
| * 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) |
| { |
| #ifdef __x86_64__ |
| if (!(current->thread.flags & THREAD_IA32)) |
| return IPC_64; |
| #endif |
| if (*cmd & IPC_64) { |
| *cmd ^= IPC_64; |
| return IPC_64; |
| } else { |
| return IPC_OLD; |
| } |
| } |
| |
| #endif /* __ia64__ */ |
| |
| #else |
| /* |
| * Dummy functions when SYSV IPC isn't configured |
| */ |
| |
| void sem_exit (void) |
| { |
| return; |
| } |
| |
| asmlinkage long sys_semget (key_t key, int nsems, int semflg) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_semop (int semid, struct sembuf *sops, unsigned nsops) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_semtimedop(int semid, struct sembuf *sops, unsigned nsops, |
| const struct timespec *timeout) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_msgget (key_t key, int msgflg) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp, |
| int msgflg) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds *buf) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_shmget (key_t key, size_t size, int shmflag) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *addr) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_shmdt (char *shmaddr) |
| { |
| return -ENOSYS; |
| } |
| |
| asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf) |
| { |
| return -ENOSYS; |
| } |
| |
| #endif /* CONFIG_SYSVIPC */ |