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/* SPDX-License-Identifier: GPL-2.0 */
#include <sys/wait.h>
#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <string.h>
#include <assert.h>
#include <sys/stat.h>
#include <stddef.h>
#include <limits.h>
#include <sys/param.h>
#include <stdbool.h>
#include "gcc-compat.h"
#include "str.h"
#include "log.h"
#include "gcc-compat.h"
#include "err.h"
#include "ipc.h"
#if (defined(__GNUC__) && defined(__i386__))
#define get16bits(d) (*((const uint16_t *) (d)))
#else
#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
+(uint32_t)(((const uint8_t *)(d))[0]) )
#endif
/*
* SuperFastHash, by Paul Hsieh.
* http://www.azillionmonkeys.com/qed/hash.html
*/
uint32_t super_fast_hash(const uint8_t *data, uint32_t len, uint32_t hash)
{
uint32_t tmp;
int rem = len & 3;
len >>= 2;
for (;len > 0; len--) {
hash += get16bits (data);
tmp = (get16bits (data+2) << 11) ^ hash;
hash = (hash << 16) ^ tmp;
data += 2*sizeof (uint16_t);
hash += hash >> 11;
}
/* Handle end cases */
switch (rem) {
case 3:
hash += get16bits (data);
hash ^= hash << 16;
hash ^= data[sizeof (uint16_t)] << 18;
hash += hash >> 11;
break;
case 2:
hash += get16bits (data);
hash ^= hash << 11;
hash += hash >> 17;
break;
case 1:
hash += *data;
hash ^= hash << 10;
hash += hash >> 1;
}
/* Force "avalanching" of final 127 bits */
hash ^= hash << 3;
hash += hash >> 5;
hash ^= hash << 4;
hash += hash >> 17;
hash ^= hash << 25;
hash += hash >> 6;
return hash;
}
static int mutex_get(key_t key, int flags)
{
int ret;
DSS_DEBUG_LOG("getting semaphore 0x%lx\n", (long)key);
ret = semget(key, 2, flags);
if (ret < 0)
return -ERRNO_TO_DSS_ERROR(errno);
return ret;
}
static int do_semop(int id, struct sembuf *sops, int num)
{
int ret;
DSS_DEBUG_LOG("calling semop\n");
do {
ret = semop(id, sops, num);
if (ret >= 0)
return 1;
} while (errno == EINTR);
return -ERRNO_TO_DSS_ERROR(errno);
}
static bool mutex_is_locked(int id)
{
struct sembuf sops;
int ret;
DSS_DEBUG_LOG("trying to lock\n");
sops.sem_num = 0;
sops.sem_op = 0;
sops.sem_flg = SEM_UNDO | IPC_NOWAIT;
ret = do_semop(id, &sops, 1);
if (ret < 0)
return true;
return false;
}
int lock_dss(uint32_t key)
{
int ret, id;
struct sembuf sops[4];
ret = mutex_get(key, IPC_CREAT | 0600);
if (ret < 0)
return ret;
id = ret;
sops[0].sem_num = 0;
sops[0].sem_op = 0;
sops[0].sem_flg = SEM_UNDO | IPC_NOWAIT;
sops[1].sem_num = 0;
sops[1].sem_op = 1;
sops[1].sem_flg = SEM_UNDO | IPC_NOWAIT;
sops[2].sem_num = 1;
sops[2].sem_op = 0;
sops[2].sem_flg = SEM_UNDO | IPC_NOWAIT;
sops[3].sem_num = 1;
sops[3].sem_op = 1;
sops[3].sem_flg = SEM_UNDO | IPC_NOWAIT;
return do_semop(id, sops, 4);
}
int get_dss_pid(uint32_t key, pid_t *pid)
{
int ret, semid;
if (pid)
*pid = 0;
ret = mutex_get(key, 0);
if (ret < 0)
return ret == -ERRNO_TO_DSS_ERROR(ENOENT)? -E_NOT_RUNNING : ret;
semid = ret;
ret = semctl(semid, 1, GETPID);
if (ret < 0)
return -E_NOT_RUNNING;
if (pid)
*pid = ret;
return mutex_is_locked(semid)? 1 : -E_NOT_RUNNING;
}
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