/* * 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/malloc.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 */ 34 void __init ipc_init (void) { sem_init(); msg_init(); shm_init(); 39 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. */ 52 void __init ipc_init_ids(struct ipc_ids* ids, int size) { int i; sema_init(&ids->sem,1); 57 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; 65 if(seq_limit > USHRT_MAX) ids->seq_max = USHRT_MAX; 67 else ids->seq_max = seq_limit; } ids->entries = ipc_alloc(sizeof(struct ipc_id)*size); 73 if(ids->entries == NULL) { printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n"); ids->size = 0; } ids->ary = SPIN_LOCK_UNLOCKED; 78 for(i=0;i<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. */ 90 int ipc_findkey(struct ipc_ids* ids, key_t key) { int id; struct kern_ipc_perm* p; 95 for (id = 0; id <= ids->max_id; id++) { p = ids->entries[id].p; 97 if(p==NULL) 98 continue; 99 if (key == p->key) 100 return id; } 102 return -1; } 105 static int grow_ary(struct ipc_ids* ids, int newsize) { struct ipc_id* new; struct ipc_id* old; int i; 111 if(newsize > IPCMNI) newsize = IPCMNI; 113 if(newsize <= ids->size) 114 return newsize; new = ipc_alloc(sizeof(struct ipc_id)*newsize); 117 if(new == NULL) 118 return ids->size; memcpy(new, ids->entries, sizeof(struct ipc_id)*ids->size); 120 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; 129 spin_unlock(&ids->ary); ipc_free(old, sizeof(struct ipc_id)*i); 131 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. */ 146 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) { int id; size = grow_ary(ids,size); 151 for (id = 0; id < size; id++) { 152 if(ids->entries[id].p == NULL) 153 goto found; } 155 return -1; found: ids->in_use++; 158 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++; 165 if(ids->seq > ids->seq_max) ids->seq = 0; spin_lock(&ids->ary); ids->entries[id].p = new; 170 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. */ 184 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id) { struct kern_ipc_perm* p; int lid = id % SEQ_MULTIPLIER; 188 if(lid > ids->size) 189 BUG(); p = ids->entries[lid].p; ids->entries[lid].p = NULL; 192 if(p==NULL) 193 BUG(); ids->in_use--; 196 if (lid == ids->max_id) { 197 do { lid--; 199 if(lid == -1) 200 break; 201 } while (ids->entries[lid].p == NULL); ids->max_id = lid; } 204 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 */ 215 void* ipc_alloc(int size) { void* out; 218 if(size > PAGE_SIZE) out = vmalloc(size); 220 else out = kmalloc(size, GFP_KERNEL); 222 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. */ 234 void ipc_free(void* ptr, int size) { 236 if(size > PAGE_SIZE) vfree(ptr); 238 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 */ 251 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; 257 if (current->euid == ipcp->cuid || current->euid == ipcp->uid) granted_mode >>= 6; 259 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) && 263 !capable(CAP_IPC_OWNER)) 264 return -1; 266 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). */ 284 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. */ 304 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; } #ifndef __ia64__ /** * 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. */ 326 int ipc_parse_version (int *cmd) { 328 if (*cmd & IPC_64) { *cmd ^= IPC_64; 330 return IPC_64; 331 } else { 332 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_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 */