/*

* SEMMNI, SEMMSL and SEMMNS are default values which can be

* modified by sysctl.

* The values has been chosen to be larger than necessary for any

* known configuration.

*

* SEMOPM should not be increased beyond 1000, otherwise there is the

* risk that semop()/semtimedop() fails due to kernel memory fragmentation when

* allocating the sop array.

*/

#define SEMMNI 32000 /* <= IPCMNI max # of semaphore identifiers */

#define SEMMSL 32000 /* <= INT_MAX max num of semaphores per id */

#define SEMMNS (SEMMNI*SEMMSL) /* <= INT_MAX max # of semaphores in system */

#define SEMOPM 500 /* <= 1 000 max num of ops per semop call */

#define SEMVMX 32767 /* <= 32767 semaphore maximum value */

#define SEMAEM SEMVMX /* adjust on exit max value */

/* semop system calls takes an array of these. */

struct sembuf {

unsigned short sem_num; /* semaphore index in array */

short sem_op; /* semaphore operation */

short sem_flg; /* operation flags */

};

/*

* SHMMNI, SHMMAX and SHMALL are default upper limits which can be

* modified by sysctl. The SHMMAX and SHMALL values have been chosen to

* be as large possible without facilitating scenarios where userspace

* causes overflows when adjusting the limits via operations of the form

* "retrieve current limit; add X; update limit". It is therefore not

* advised to make SHMMAX and SHMALL any larger. These limits are

* suitable for both 32 and 64-bit systems.

*/

#define SHMMIN 1 /* min shared seg size (bytes) */

#define SHMMNI 4096 /* max num of segs system wide */

#define SHMMAX (ULONG_MAX - (1UL << 24)) /* max shared seg size (bytes) */

#define SHMALL (ULONG_MAX - (1UL << 24)) /* max shm system wide (pages) */

#define SHMSEG SHMMNI /* max shared segs per process */