summaryrefslogtreecommitdiff
path: root/ipc/sem.c
diff options
context:
space:
mode:
Diffstat (limited to 'ipc/sem.c')
-rw-r--r--ipc/sem.c81
1 files changed, 53 insertions, 28 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index 1cf56279a84c..2994da8ccc7f 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -88,13 +88,47 @@
#include <linux/uaccess.h>
#include "util.h"
+/* One semaphore structure for each semaphore in the system. */
+struct sem {
+ int semval; /* current value */
+ /*
+ * PID of the process that last modified the semaphore. For
+ * Linux, specifically these are:
+ * - semop
+ * - semctl, via SETVAL and SETALL.
+ * - at task exit when performing undo adjustments (see exit_sem).
+ */
+ struct pid *sempid;
+ spinlock_t lock; /* spinlock for fine-grained semtimedop */
+ struct list_head pending_alter; /* pending single-sop operations */
+ /* that alter the semaphore */
+ struct list_head pending_const; /* pending single-sop operations */
+ /* that do not alter the semaphore*/
+ time_t sem_otime; /* candidate for sem_otime */
+} ____cacheline_aligned_in_smp;
+
+/* One sem_array data structure for each set of semaphores in the system. */
+struct sem_array {
+ struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
+ time64_t sem_ctime; /* create/last semctl() time */
+ struct list_head pending_alter; /* pending operations */
+ /* that alter the array */
+ struct list_head pending_const; /* pending complex operations */
+ /* that do not alter semvals */
+ struct list_head list_id; /* undo requests on this array */
+ int sem_nsems; /* no. of semaphores in array */
+ int complex_count; /* pending complex operations */
+ unsigned int use_global_lock;/* >0: global lock required */
+
+ struct sem sems[];
+} __randomize_layout;
/* One queue for each sleeping process in the system. */
struct sem_queue {
struct list_head list; /* queue of pending operations */
struct task_struct *sleeper; /* this process */
struct sem_undo *undo; /* undo structure */
- int pid; /* process id of requesting process */
+ struct pid *pid; /* process id of requesting process */
int status; /* completion status of operation */
struct sembuf *sops; /* array of pending operations */
struct sembuf *blocking; /* the operation that blocked */
@@ -265,7 +299,7 @@ static void sem_rcu_free(struct rcu_head *head)
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
- security_sem_free(sma);
+ security_sem_free(&sma->sem_perm);
kvfree(sma);
}
@@ -495,7 +529,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
sma->sem_perm.key = key;
sma->sem_perm.security = NULL;
- retval = security_sem_alloc(sma);
+ retval = security_sem_alloc(&sma->sem_perm);
if (retval) {
kvfree(sma);
return retval;
@@ -533,17 +567,6 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
/*
* Called with sem_ids.rwsem and ipcp locked.
*/
-static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
-{
- struct sem_array *sma;
-
- sma = container_of(ipcp, struct sem_array, sem_perm);
- return security_sem_associate(sma, semflg);
-}
-
-/*
- * Called with sem_ids.rwsem and ipcp locked.
- */
static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
{
@@ -561,7 +584,7 @@ long ksys_semget(key_t key, int nsems, int semflg)
struct ipc_namespace *ns;
static const struct ipc_ops sem_ops = {
.getnew = newary,
- .associate = sem_security,
+ .associate = security_sem_associate,
.more_checks = sem_more_checks,
};
struct ipc_params sem_params;
@@ -602,7 +625,8 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
*/
static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
{
- int result, sem_op, nsops, pid;
+ int result, sem_op, nsops;
+ struct pid *pid;
struct sembuf *sop;
struct sem *curr;
struct sembuf *sops;
@@ -640,7 +664,7 @@ static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
sop--;
pid = q->pid;
while (sop >= sops) {
- sma->sems[sop->sem_num].sempid = pid;
+ ipc_update_pid(&sma->sems[sop->sem_num].sempid, pid);
sop--;
}
@@ -727,7 +751,7 @@ static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
un->semadj[sop->sem_num] = undo;
}
curr->semval += sem_op;
- curr->sempid = q->pid;
+ ipc_update_pid(&curr->sempid, q->pid);
}
return 0;
@@ -1134,6 +1158,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
+ ipc_update_pid(&sem->sempid, NULL);
}
/* Remove the semaphore set from the IDR */
@@ -1214,7 +1239,7 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
goto out_unlock;
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock;
@@ -1305,7 +1330,7 @@ static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
return -EACCES;
}
- err = security_sem_semctl(sma, SETVAL);
+ err = security_sem_semctl(&sma->sem_perm, SETVAL);
if (err) {
rcu_read_unlock();
return -EACCES;
@@ -1326,7 +1351,7 @@ static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
un->semadj[semnum] = 0;
curr->semval = val;
- curr->sempid = task_tgid_vnr(current);
+ ipc_update_pid(&curr->sempid, task_tgid(current));
sma->sem_ctime = ktime_get_real_seconds();
/* maybe some queued-up processes were waiting for this */
do_smart_update(sma, NULL, 0, 0, &wake_q);
@@ -1359,7 +1384,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO))
goto out_rcu_wakeup;
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_rcu_wakeup;
@@ -1447,7 +1472,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
for (i = 0; i < nsems; i++) {
sma->sems[i].semval = sem_io[i];
- sma->sems[i].sempid = task_tgid_vnr(current);
+ ipc_update_pid(&sma->sems[i].sempid, task_tgid(current));
}
ipc_assert_locked_object(&sma->sem_perm);
@@ -1479,7 +1504,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
err = curr->semval;
goto out_unlock;
case GETPID:
- err = curr->sempid;
+ err = pid_vnr(curr->sempid);
goto out_unlock;
case GETNCNT:
err = count_semcnt(sma, semnum, 0);
@@ -1550,7 +1575,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
sma = container_of(ipcp, struct sem_array, sem_perm);
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock1;
@@ -1977,7 +2002,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
goto out_free;
}
- error = security_sem_semop(sma, sops, nsops, alter);
+ error = security_sem_semop(&sma->sem_perm, sops, nsops, alter);
if (error) {
rcu_read_unlock();
goto out_free;
@@ -2008,7 +2033,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
queue.sops = sops;
queue.nsops = nsops;
queue.undo = un;
- queue.pid = task_tgid_vnr(current);
+ queue.pid = task_tgid(current);
queue.alter = alter;
queue.dupsop = dupsop;
@@ -2315,7 +2340,7 @@ void exit_sem(struct task_struct *tsk)
semaphore->semval = 0;
if (semaphore->semval > SEMVMX)
semaphore->semval = SEMVMX;
- semaphore->sempid = task_tgid_vnr(current);
+ ipc_update_pid(&semaphore->sempid, task_tgid(current));
}
}
/* maybe some queued-up processes were waiting for this */
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2024-12-30 22:55:52 +0000