508 lines
12 KiB
C
508 lines
12 KiB
C
/*
|
|
* linux/ipc/sem.c
|
|
* Copyright (C) 1992 Krishna Balasubramanian
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <asm/segment.h>
|
|
#include <linux/string.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sem.h>
|
|
#include <linux/ipc.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/malloc.h>
|
|
|
|
extern int ipcperms (struct ipc_perm *ipcp, short semflg);
|
|
static int newary (key_t, int, int);
|
|
static int findkey (key_t key);
|
|
static void freeary (int id);
|
|
|
|
static struct semid_ds *semary[SEMMNI];
|
|
static int used_sems = 0, used_semids = 0;
|
|
static struct wait_queue *sem_lock = NULL;
|
|
static int max_semid = 0;
|
|
|
|
static unsigned short sem_seq = 0;
|
|
|
|
void sem_init (void)
|
|
{
|
|
int i=0;
|
|
|
|
sem_lock = NULL;
|
|
used_sems = used_semids = max_semid = sem_seq = 0;
|
|
for (i=0; i < SEMMNI; i++)
|
|
semary[i] = (struct semid_ds *) IPC_UNUSED;
|
|
return;
|
|
}
|
|
|
|
static int findkey (key_t key)
|
|
{
|
|
int id;
|
|
struct semid_ds *sma;
|
|
|
|
for (id=0; id <= max_semid; id++) {
|
|
while ((sma = semary[id]) == IPC_NOID)
|
|
interruptible_sleep_on (&sem_lock);
|
|
if (sma == IPC_UNUSED)
|
|
continue;
|
|
if (key == sma->sem_perm.key)
|
|
return id;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int newary (key_t key, int nsems, int semflg)
|
|
{
|
|
int id;
|
|
struct semid_ds *sma;
|
|
struct ipc_perm *ipcp;
|
|
int size;
|
|
|
|
if (!nsems)
|
|
return -EINVAL;
|
|
if (used_sems + nsems > SEMMNS)
|
|
return -ENOSPC;
|
|
for (id=0; id < SEMMNI; id++)
|
|
if (semary[id] == IPC_UNUSED) {
|
|
semary[id] = (struct semid_ds *) IPC_NOID;
|
|
goto found;
|
|
}
|
|
return -ENOSPC;
|
|
found:
|
|
size = sizeof (*sma) + nsems * sizeof (struct sem);
|
|
used_sems += nsems;
|
|
sma = (struct semid_ds *) kmalloc (size, GFP_KERNEL);
|
|
if (!sma) {
|
|
semary[id] = (struct semid_ds *) IPC_UNUSED;
|
|
used_sems -= nsems;
|
|
if (sem_lock)
|
|
wake_up (&sem_lock);
|
|
return -ENOMEM;
|
|
}
|
|
memset (sma, 0, size);
|
|
sma->sem_base = (struct sem *) &sma[1];
|
|
ipcp = &sma->sem_perm;
|
|
ipcp->mode = (semflg & S_IRWXUGO);
|
|
ipcp->key = key;
|
|
ipcp->cuid = ipcp->uid = current->euid;
|
|
ipcp->gid = ipcp->cgid = current->egid;
|
|
ipcp->seq = sem_seq;
|
|
sma->eventn = sma->eventz = NULL;
|
|
sma->sem_nsems = nsems;
|
|
sma->sem_ctime = CURRENT_TIME;
|
|
if (id > max_semid)
|
|
max_semid = id;
|
|
used_semids++;
|
|
semary[id] = sma;
|
|
if (sem_lock)
|
|
wake_up (&sem_lock);
|
|
return (int) sem_seq * SEMMNI + id;
|
|
}
|
|
|
|
int sys_semget (key_t key, int nsems, int semflg)
|
|
{
|
|
int id;
|
|
struct semid_ds *sma;
|
|
|
|
if (nsems < 0 || nsems > SEMMSL)
|
|
return -EINVAL;
|
|
if (key == IPC_PRIVATE)
|
|
return newary(key, nsems, semflg);
|
|
if ((id = findkey (key)) == -1) { /* key not used */
|
|
if (!(semflg & IPC_CREAT))
|
|
return -ENOENT;
|
|
return newary(key, nsems, semflg);
|
|
}
|
|
if (semflg & IPC_CREAT && semflg & IPC_EXCL)
|
|
return -EEXIST;
|
|
sma = semary[id];
|
|
if (nsems > sma->sem_nsems)
|
|
return -EINVAL;
|
|
if (ipcperms(&sma->sem_perm, semflg))
|
|
return -EACCES;
|
|
return sma->sem_perm.seq*SEMMNI + id;
|
|
}
|
|
|
|
static void freeary (int id)
|
|
{
|
|
struct semid_ds *sma = semary[id];
|
|
struct sem_undo *un;
|
|
|
|
sma->sem_perm.seq++;
|
|
sem_seq++;
|
|
used_sems -= sma->sem_nsems;
|
|
if (id == max_semid)
|
|
while (max_semid && (semary[--max_semid] == IPC_UNUSED));
|
|
semary[id] = (struct semid_ds *) IPC_UNUSED;
|
|
used_semids--;
|
|
for (un=sma->undo; un; un=un->id_next)
|
|
un->semadj = 0;
|
|
while (sma->eventz || sma->eventn) {
|
|
if (sma->eventz)
|
|
wake_up (&sma->eventz);
|
|
if (sma->eventn)
|
|
wake_up (&sma->eventn);
|
|
schedule();
|
|
}
|
|
kfree_s (sma, sizeof (*sma) + sma->sem_nsems * sizeof (struct sem));
|
|
return;
|
|
}
|
|
|
|
int sys_semctl (int semid, int semnum, int cmd, void *arg)
|
|
{
|
|
int i, id, val = 0;
|
|
struct semid_ds *sma, *buf = NULL, tbuf;
|
|
struct ipc_perm *ipcp;
|
|
struct sem *curr;
|
|
struct sem_undo *un;
|
|
ushort nsems, *array = NULL;
|
|
ushort sem_io[SEMMSL];
|
|
|
|
if (semid < 0 || semnum < 0 || cmd < 0)
|
|
return -EINVAL;
|
|
|
|
switch (cmd) {
|
|
case IPC_INFO:
|
|
case SEM_INFO:
|
|
{
|
|
struct seminfo seminfo, *tmp;
|
|
if (!arg || ! (tmp = (struct seminfo *) get_fs_long((int *)arg)))
|
|
return -EFAULT;
|
|
seminfo.semmni = SEMMNI;
|
|
seminfo.semmns = SEMMNS;
|
|
seminfo.semmsl = SEMMSL;
|
|
seminfo.semopm = SEMOPM;
|
|
seminfo.semvmx = SEMVMX;
|
|
seminfo.semmnu = SEMMNU;
|
|
seminfo.semmap = SEMMAP;
|
|
seminfo.semume = SEMUME;
|
|
seminfo.semusz = SEMUSZ;
|
|
seminfo.semaem = SEMAEM;
|
|
if (cmd == SEM_INFO) {
|
|
seminfo.semusz = used_semids;
|
|
seminfo.semaem = used_sems;
|
|
}
|
|
i= verify_area(VERIFY_WRITE, tmp, sizeof(struct seminfo));
|
|
if (i)
|
|
return i;
|
|
memcpy_tofs (tmp, &seminfo, sizeof(struct seminfo));
|
|
return max_semid;
|
|
}
|
|
|
|
case SEM_STAT:
|
|
if (!arg || ! (buf = (struct semid_ds *) get_fs_long((int *) arg)))
|
|
return -EFAULT;
|
|
i = verify_area (VERIFY_WRITE, buf, sizeof (*sma));
|
|
if (i)
|
|
return i;
|
|
if (semid > max_semid)
|
|
return -EINVAL;
|
|
sma = semary[semid];
|
|
if (sma == IPC_UNUSED || sma == IPC_NOID)
|
|
return -EINVAL;
|
|
if (ipcperms (&sma->sem_perm, S_IRUGO))
|
|
return -EACCES;
|
|
id = semid + sma->sem_perm.seq * SEMMNI;
|
|
memcpy_tofs (buf, sma, sizeof(*sma));
|
|
return id;
|
|
}
|
|
|
|
id = semid % SEMMNI;
|
|
sma = semary [id];
|
|
if (sma == IPC_UNUSED || sma == IPC_NOID)
|
|
return -EINVAL;
|
|
ipcp = &sma->sem_perm;
|
|
nsems = sma->sem_nsems;
|
|
if (ipcp->seq != semid / SEMMNI)
|
|
return -EIDRM;
|
|
if (semnum >= nsems)
|
|
return -EINVAL;
|
|
curr = &sma->sem_base[semnum];
|
|
|
|
switch (cmd) {
|
|
case GETVAL:
|
|
case GETPID:
|
|
case GETNCNT:
|
|
case GETZCNT:
|
|
case GETALL:
|
|
if (ipcperms (ipcp, S_IRUGO))
|
|
return -EACCES;
|
|
switch (cmd) {
|
|
case GETVAL : return curr->semval;
|
|
case GETPID : return curr->sempid;
|
|
case GETNCNT: return curr->semncnt;
|
|
case GETZCNT: return curr->semzcnt;
|
|
case GETALL:
|
|
if (!arg || ! (array = (ushort *) get_fs_long((int *) arg)))
|
|
return -EFAULT;
|
|
i = verify_area (VERIFY_WRITE, array, nsems* sizeof(short));
|
|
if (i)
|
|
return i;
|
|
}
|
|
break;
|
|
case SETVAL:
|
|
if (!arg)
|
|
return -EFAULT;
|
|
if ((val = (int) get_fs_long ((int *) arg)) > SEMVMX || val < 0)
|
|
return -ERANGE;
|
|
break;
|
|
case IPC_RMID:
|
|
if (suser() || current->euid == ipcp->cuid ||
|
|
current->euid == ipcp->uid) {
|
|
freeary (id);
|
|
return 0;
|
|
}
|
|
return -EPERM;
|
|
case SETALL: /* arg is a pointer to an array of ushort */
|
|
if (!arg || ! (array = (ushort *) get_fs_long ((int *) arg)) )
|
|
return -EFAULT;
|
|
if ((i = verify_area (VERIFY_READ, array, sizeof tbuf)))
|
|
return i;
|
|
memcpy_fromfs (sem_io, array, nsems*sizeof(ushort));
|
|
for (i=0; i< nsems; i++)
|
|
if (sem_io[i] > SEMVMX)
|
|
return -ERANGE;
|
|
break;
|
|
case IPC_STAT:
|
|
if (!arg || !(buf = (struct semid_ds *) get_fs_long((int *) arg)))
|
|
return -EFAULT;
|
|
if ((i = verify_area (VERIFY_WRITE, arg, sizeof tbuf)))
|
|
return i;
|
|
break;
|
|
case IPC_SET:
|
|
if (!arg || !(buf = (struct semid_ds *) get_fs_long((int *) arg)))
|
|
return -EFAULT;
|
|
if ((i = verify_area (VERIFY_READ, buf, sizeof tbuf)))
|
|
return i;
|
|
memcpy_fromfs (&tbuf, buf, sizeof tbuf);
|
|
break;
|
|
}
|
|
|
|
if (semary[id] == IPC_UNUSED || semary[id] == IPC_NOID)
|
|
return -EIDRM;
|
|
if (ipcp->seq != semid / SEMMNI)
|
|
return -EIDRM;
|
|
|
|
switch (cmd) {
|
|
case GETALL:
|
|
if (ipcperms (ipcp, S_IRUGO))
|
|
return -EACCES;
|
|
for (i=0; i< sma->sem_nsems; i++)
|
|
sem_io[i] = sma->sem_base[i].semval;
|
|
memcpy_tofs (array, sem_io, nsems*sizeof(ushort));
|
|
break;
|
|
case SETVAL:
|
|
if (ipcperms (ipcp, S_IWUGO))
|
|
return -EACCES;
|
|
for (un = sma->undo; un; un = un->id_next)
|
|
if (semnum == un->sem_num)
|
|
un->semadj = 0;
|
|
sma->sem_ctime = CURRENT_TIME;
|
|
curr->semval = val;
|
|
if (sma->eventn)
|
|
wake_up (&sma->eventn);
|
|
if (sma->eventz)
|
|
wake_up (&sma->eventz);
|
|
break;
|
|
case IPC_SET:
|
|
if (suser() || current->euid == ipcp->cuid ||
|
|
current->euid == ipcp->uid) {
|
|
ipcp->uid = tbuf.sem_perm.uid;
|
|
ipcp->gid = tbuf.sem_perm.gid;
|
|
ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
|
|
| (tbuf.sem_perm.mode & S_IRWXUGO);
|
|
sma->sem_ctime = CURRENT_TIME;
|
|
return 0;
|
|
}
|
|
return -EPERM;
|
|
case IPC_STAT:
|
|
if (ipcperms (ipcp, S_IRUGO))
|
|
return -EACCES;
|
|
memcpy_tofs (buf, sma, sizeof (*sma));
|
|
break;
|
|
case SETALL:
|
|
if (ipcperms (ipcp, S_IWUGO))
|
|
return -EACCES;
|
|
for (i=0; i<nsems; i++)
|
|
sma->sem_base[i].semval = sem_io[i];
|
|
for (un = sma->undo; un; un = un->id_next)
|
|
un->semadj = 0;
|
|
if (sma->eventn)
|
|
wake_up (&sma->eventn);
|
|
if (sma->eventz)
|
|
wake_up (&sma->eventz);
|
|
sma->sem_ctime = CURRENT_TIME;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int sys_semop (int semid, struct sembuf *tsops, unsigned nsops)
|
|
{
|
|
int i, id;
|
|
struct semid_ds *sma;
|
|
struct sem *curr = NULL;
|
|
struct sembuf sops[SEMOPM], *sop;
|
|
struct sem_undo *un;
|
|
int undos = 0, alter = 0, semncnt = 0, semzcnt = 0;
|
|
|
|
if (nsops < 1 || semid < 0)
|
|
return -EINVAL;
|
|
if (nsops > SEMOPM)
|
|
return -E2BIG;
|
|
if (!tsops)
|
|
return -EFAULT;
|
|
memcpy_fromfs (sops, tsops, nsops * sizeof(*tsops));
|
|
id = semid % SEMMNI;
|
|
if ((sma = semary[id]) == IPC_UNUSED || sma == IPC_NOID)
|
|
return -EINVAL;
|
|
for (i=0; i<nsops; i++) {
|
|
sop = &sops[i];
|
|
if (sop->sem_num > sma->sem_nsems)
|
|
return -EFBIG;
|
|
if (sop->sem_flg & SEM_UNDO)
|
|
undos++;
|
|
if (sop->sem_op) {
|
|
alter++;
|
|
if (sop->sem_op > 0)
|
|
semncnt ++;
|
|
}
|
|
}
|
|
if (ipcperms(&sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
|
|
return -EACCES;
|
|
/*
|
|
* ensure every sop with undo gets an undo structure
|
|
*/
|
|
if (undos) {
|
|
for (i=0; i<nsops; i++) {
|
|
if (!(sops[i].sem_flg & SEM_UNDO))
|
|
continue;
|
|
for (un = current->semun; un; un = un->proc_next)
|
|
if ((un->semid == semid) &&
|
|
(un->sem_num == sops[i].sem_num))
|
|
break;
|
|
if (un)
|
|
continue;
|
|
un = (struct sem_undo *)
|
|
kmalloc (sizeof(*un), GFP_ATOMIC);
|
|
if (!un)
|
|
return -ENOMEM; /* freed on exit */
|
|
un->semid = semid;
|
|
un->semadj = 0;
|
|
un->sem_num = sops[i].sem_num;
|
|
un->proc_next = current->semun;
|
|
current->semun = un;
|
|
un->id_next = sma->undo;
|
|
sma->undo = un;
|
|
}
|
|
}
|
|
|
|
slept:
|
|
if (sma->sem_perm.seq != semid / SEMMNI)
|
|
return -EIDRM;
|
|
for (i=0; i<nsops; i++) {
|
|
sop = &sops[i];
|
|
curr = &sma->sem_base[sop->sem_num];
|
|
if (sop->sem_op + curr->semval > SEMVMX)
|
|
return -ERANGE;
|
|
if (!sop->sem_op && curr->semval) {
|
|
if (sop->sem_flg & IPC_NOWAIT)
|
|
return -EAGAIN;
|
|
if (current->signal & ~current->blocked)
|
|
return -EINTR;
|
|
curr->semzcnt++;
|
|
interruptible_sleep_on (&sma->eventz);
|
|
curr->semzcnt--;
|
|
goto slept;
|
|
}
|
|
if ((sop->sem_op + curr->semval < 0) ) {
|
|
if (sop->sem_flg & IPC_NOWAIT)
|
|
return -EAGAIN;
|
|
if (current->signal & ~current->blocked)
|
|
return -EINTR;
|
|
curr->semncnt++;
|
|
interruptible_sleep_on (&sma->eventn);
|
|
curr->semncnt--;
|
|
goto slept;
|
|
}
|
|
}
|
|
|
|
for (i=0; i<nsops; i++) {
|
|
sop = &sops[i];
|
|
curr = &sma->sem_base[sop->sem_num];
|
|
curr->sempid = current->pid;
|
|
if (!(curr->semval += sop->sem_op))
|
|
semzcnt++;
|
|
if (!(sop->sem_flg & SEM_UNDO))
|
|
continue;
|
|
for (un = current->semun; un; un = un->proc_next)
|
|
if ((un->semid == semid) &&
|
|
(un->sem_num == sop->sem_num))
|
|
break;
|
|
if (!un) {
|
|
printk ("semop : no undo for op %d\n", i);
|
|
continue;
|
|
}
|
|
un->semadj -= sop->sem_op;
|
|
}
|
|
sma->sem_otime = CURRENT_TIME;
|
|
if (semncnt && sma->eventn)
|
|
wake_up(&sma->eventn);
|
|
if (semzcnt && sma->eventz)
|
|
wake_up(&sma->eventz);
|
|
return curr->semval;
|
|
}
|
|
|
|
/*
|
|
* add semadj values to semaphores, free undo structures.
|
|
* undo structures are not freed when semaphore arrays are destroyed
|
|
* so some of them may be out of date.
|
|
*/
|
|
void sem_exit (void)
|
|
{
|
|
struct sem_undo *u, *un = NULL, **up, **unp;
|
|
struct semid_ds *sma;
|
|
struct sem *sem = NULL;
|
|
|
|
for (up = ¤t->semun; (u = *up); *up = u->proc_next, kfree(u)) {
|
|
sma = semary[u->semid % SEMMNI];
|
|
if (sma == IPC_UNUSED || sma == IPC_NOID)
|
|
continue;
|
|
if (sma->sem_perm.seq != u->semid / SEMMNI)
|
|
continue;
|
|
for (unp = &sma->undo; (un = *unp); unp = &un->id_next) {
|
|
if (u == un)
|
|
goto found;
|
|
}
|
|
printk ("sem_exit undo list error id=%d\n", u->semid);
|
|
break;
|
|
found:
|
|
*unp = un->id_next;
|
|
if (!un->semadj)
|
|
continue;
|
|
while (1) {
|
|
if (sma->sem_perm.seq != un->semid / SEMMNI)
|
|
break;
|
|
sem = &sma->sem_base[un->sem_num];
|
|
if (sem->semval + un->semadj >= 0) {
|
|
sem->semval += un->semadj;
|
|
sem->sempid = current->pid;
|
|
sma->sem_otime = CURRENT_TIME;
|
|
if (un->semadj > 0 && sma->eventn)
|
|
wake_up (&sma->eventn);
|
|
if (!sem->semval && sma->eventz)
|
|
wake_up (&sma->eventz);
|
|
break;
|
|
}
|
|
if (current->signal & ~current->blocked)
|
|
break;
|
|
sem->semncnt++;
|
|
interruptible_sleep_on (&sma->eventn);
|
|
sem->semncnt--;
|
|
}
|
|
}
|
|
current->semun = NULL;
|
|
return;
|
|
}
|