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bmomjianbmomjian
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> I have improved the System V semaphore emulation of the QNX4 port.
Please > apply the attached patch to > > backend/port/qnx4 > > Andreas Kardos >
1 parent e3fb902 commit e02cde4

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-58
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3 files changed

+145
-58
lines changed

‎src/backend/port/qnx4/sem.c

Lines changed: 87 additions & 38 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.c,v 1.1 1999/12/16 16:52:52 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.c,v 1.2 2000/03/14 18:12:06 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -21,23 +21,31 @@
2121
#include <sys/mman.h>
2222
#include "postgres.h"
2323
#include "storage/ipc.h"
24+
#include "storage/proc.h"
2425
#include <sys/sem.h>
2526

2627

27-
#define SETMAX 32
28-
#define SEMMAX 16
28+
#define SETMAX ((MAXBACKENDS + PROC_NSEMS_PER_SET - 1) / PROC_NSEMS_PER_SET)
29+
#define SEMMAX (PROC_NSEMS_PER_SET)
30+
#define OPMAX 8
2931

30-
#define MODE 0777
32+
#define MODE 0700
3133
#define SHM_INFO_NAME "SysV_Sem_Info"
3234

3335

36+
struct pending_ops {
37+
int op[OPMAX]; /* array of pending operations */
38+
int idx; /* index of first free array member */
39+
};
40+
3441
struct sem_info {
3542
sem_t sem;
3643
struct {
37-
key_t key;
38-
int nsems;
39-
sem_t sem[SEMMAX]; /* array of semaphores */
40-
pid_t pid[SEMMAX]; /* array of PIDs */
44+
key_t key;
45+
int nsems;
46+
sem_t sem[SEMMAX]; /* array of POSIX semaphores */
47+
struct sem semV[SEMMAX]; /* array of System V semaphore structures */
48+
struct pending_ops pendingOps[SEMMAX]; /* array of pending operations */
4149
} set[SETMAX];
4250
};
4351

@@ -46,7 +54,7 @@ static struct sem_info *SemInfo = ( struct sem_info * )-1;
4654

4755
int semctl( int semid, int semnum, int cmd, /*...*/union semun arg )
4856
{
49-
int r;
57+
int r = 0;
5058

5159
sem_wait( &SemInfo->sem );
5260

@@ -58,30 +66,38 @@ int semctl( int semid, int semnum, int cmd, /*...*/union semun arg )
5866
}
5967

6068
switch( cmd ) {
69+
case GETNCNT:
70+
r = SemInfo->set[semid].semV[semnum].semncnt;
71+
break;
72+
6173
case GETPID:
62-
r = SemInfo->set[semid].pid[semnum];
74+
r = SemInfo->set[semid].semV[semnum].sempid;
6375
break;
6476

6577
case GETVAL:
66-
r = SemInfo->set[semid].sem[semnum].value;
78+
r = SemInfo->set[semid].semV[semnum].semval;
6779
break;
6880

6981
case GETALL:
7082
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
71-
arg.array[semnum] = SemInfo->set[semid].sem[semnum].value;
83+
arg.array[semnum] = SemInfo->set[semid].semV[semnum].semval;
7284
}
7385
break;
7486

7587
case SETVAL:
76-
SemInfo->set[semid].sem[semnum].value = arg.val;
88+
SemInfo->set[semid].semV[semnum].semval = arg.val;
7789
break;
7890

7991
case SETALL:
8092
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
81-
SemInfo->set[semid].sem[semnum].value = arg.array[semnum];
93+
SemInfo->set[semid].semV[semnum].semval = arg.array[semnum];
8294
}
8395
break;
8496

97+
case GETZCNT:
98+
r = SemInfo->set[semid].semV[semnum].semzcnt;
99+
break;
100+
85101
case IPC_RMID:
86102
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
87103
if( sem_destroy( &SemInfo->set[semid].sem[semnum] ) == -1 ) {
@@ -121,12 +137,16 @@ int semget( key_t key, int nsems, int semflg )
121137
exist = 1;
122138
fd = shm_open( SHM_INFO_NAME, O_RDWR | O_CREAT, MODE );
123139
}
124-
if( fd == -1 ) return fd;
140+
if( fd == -1 ) {
141+
return fd;
142+
}
125143
/* The size may only be set once. Ignore errors. */
126144
ltrunc( fd, sizeof( struct sem_info ), SEEK_SET );
127145
SemInfo = mmap( NULL, sizeof( struct sem_info ),
128146
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 );
129-
if( SemInfo == MAP_FAILED ) return -1;
147+
if( SemInfo == MAP_FAILED ) {
148+
return -1;
149+
}
130150
if( !exist ) {
131151
/* create semaphore for locking */
132152
sem_init( &SemInfo->sem, 1, 1 );
@@ -196,12 +216,12 @@ int semget( key_t key, int nsems, int semflg )
196216

197217
sem_post( &SemInfo->sem );
198218

199-
return 0;
219+
return semid;
200220
}
201221

202222
int semop( int semid, struct sembuf *sops, size_t nsops )
203223
{
204-
int i, j, r = 0, r1, errno1 = 0;
224+
int i, r = 0, r1, errno1 = 0, op;
205225

206226
sem_wait( &SemInfo->sem );
207227

@@ -220,38 +240,67 @@ int semop( int semid, struct sembuf *sops, size_t nsops )
220240

221241
for( i = 0; i < nsops; i++ ) {
222242
if( sops[i].sem_op < 0 ) {
223-
if( sops[i].sem_flg & IPC_NOWAIT ) {
224-
for( j = 0; j < -sops[i].sem_op; j++ ) {
225-
if( sem_trywait( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) {
226-
errno1 = errno;
227-
r = -1;
228-
}
243+
if( SemInfo->set[semid].semV[sops[i].sem_num].semval < -sops[i].sem_op ) {
244+
if( sops[i].sem_flg & IPC_NOWAIT ) {
245+
sem_post( &SemInfo->sem );
246+
errno = EAGAIN;
247+
return -1;
229248
}
249+
SemInfo->set[semid].semV[sops[i].sem_num].semncnt++;
250+
if( SemInfo->set[semid].pendingOps[sops[i].sem_num].idx >= OPMAX ) {
251+
/* pending operations array overflow */
252+
sem_post( &SemInfo->sem );
253+
errno = ERANGE;
254+
return -1;
255+
}
256+
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx++] = sops[i].sem_op;
257+
/* suspend */
258+
sem_post( &SemInfo->sem ); /* avoid deadlock */
259+
r1 = sem_wait( &SemInfo->set[semid].sem[sops[i].sem_num] );
260+
sem_wait( &SemInfo->sem );
261+
if( r1 ) {
262+
errno1 = errno;
263+
r = r1;
264+
/* remove pending operation */
265+
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0;
266+
}
267+
else {
268+
SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op;
269+
}
270+
SemInfo->set[semid].semV[sops[i].sem_num].semncnt--;
230271
}
231272
else {
232-
for( j = 0; j < -sops[i].sem_op; j++ ) {
233-
sem_post( &SemInfo->sem ); /* avoid deadlock */
234-
r1 = sem_wait( &SemInfo->set[semid].sem[sops[i].sem_num] );
235-
sem_wait( &SemInfo->sem );
236-
if( r1 ) {
237-
errno1 = errno;
238-
r = r1;
239-
}
240-
}
273+
SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op;
241274
}
242275
}
243276
else if( sops[i].sem_op > 0 ) {
244-
for( j = 0; j < sops[i].sem_op; j++ ) {
245-
if( sem_post( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) {
246-
errno1 = errno;
247-
r = -1;
277+
SemInfo->set[semid].semV[sops[i].sem_num].semval += sops[i].sem_op;
278+
op = sops[i].sem_op;
279+
while( op > 0 && SemInfo->set[semid].pendingOps[sops[i].sem_num].idx > 0 ) { /* operations pending */
280+
if( SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx-1] + op >= 0 ) {
281+
/* unsuspend processes */
282+
if( sem_post( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) {
283+
errno1 = errno;
284+
r = -1;
285+
}
286+
/* adjust pending operations */
287+
op += SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx];
288+
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0;
289+
}
290+
else {
291+
/* adjust pending operations */
292+
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx-1] += op;
293+
op = 0;
248294
}
249295
}
250296
}
251297
else /* sops[i].sem_op == 0 */ {
252298
/* not supported */
299+
sem_post( &SemInfo->sem );
300+
errno = ENOSYS;
301+
return -1;
253302
}
254-
SemInfo->set[semid].pid[sops[i].sem_num] = getpid( );
303+
SemInfo->set[semid].semV[sops[i].sem_num].sempid = getpid( );
255304
}
256305

257306
sem_post( &SemInfo->sem );

‎src/backend/port/qnx4/sem.h

Lines changed: 26 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.h,v 1.1 1999/12/16 16:52:52 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.h,v 1.2 2000/03/14 18:12:06 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -17,37 +17,48 @@
1717

1818
#include <sys/ipc.h>
1919

20-
#ifdef __cplusplus
20+
#ifdef __cplusplus
2121
extern "C" {
2222
#endif
2323

2424
/*
25-
* Semctl Command Definitions.
25+
* Semctl Command Definitions.
2626
*/
2727

28-
#define GETNCNT 3 /* get semncnt */
29-
#define GETPID 4 /* get sempid */
30-
#define GETVAL 5 /* get semval */
31-
#define GETALL 6 /* get all semval's */
32-
#define GETZCNT 7 /* get semzcnt */
33-
#define SETVAL 8 /* set semval */
34-
#define SETALL 9 /* set all semval's */
28+
#define GETNCNT 3 /* get semncnt */
29+
#define GETPID 4 /* get sempid */
30+
#define GETVAL 5 /* get semval */
31+
#define GETALL 6 /* get all semval's */
32+
#define GETZCNT 7 /* get semzcnt */
33+
#define SETVAL 8 /* set semval */
34+
#define SETALL 9 /* set all semval's */
3535

3636
/*
37-
* User semaphore template for semop system calls.
37+
* There is one semaphore structure for each semaphore in the system.
38+
*/
39+
40+
struct sem {
41+
ushort_t semval; /* semaphore text map address */
42+
pid_t sempid; /* pid of last operation */
43+
ushort_t semncnt; /* # awaiting semval > cval */
44+
ushort_t semzcnt; /* # awaiting semval = 0 */
45+
};
46+
47+
/*
48+
* User semaphore template for semop system calls.
3849
*/
3950

4051
struct sembuf {
41-
ushort_t sem_num; /* semaphore # */
42-
short sem_op; /* semaphore operation */
43-
short sem_flg; /* operation flags */
52+
ushort_t sem_num; /* semaphore # */
53+
short sem_op; /* semaphore operation */
54+
short sem_flg; /* operation flags */
4455
};
4556

4657
extern int semctl( int semid, int semnum, int cmd, /*...*/union semun arg );
4758
extern int semget( key_t key, int nsems, int semflg );
4859
extern int semop( int semid, struct sembuf *sops, size_t nsops );
4960

50-
#ifdef __cplusplus
61+
#ifdef __cplusplus
5162
}
5263
#endif
5364

‎src/backend/port/qnx4/tstsem.c

Lines changed: 32 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -7,12 +7,13 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/tstsem.c,v 1.1 1999/12/16 16:52:52 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/tstsem.c,v 1.2 2000/03/14 18:12:06 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
1414

1515

16+
#include <signal.h>
1617
#include <stdio.h>
1718
#include <stdlib.h>
1819
#include <unistd.h>
@@ -22,9 +23,18 @@
2223
#include <sys/sem.h>
2324

2425

25-
#define SEMMAX 1
26-
#define OPSMAX 1
26+
#define SEMMAX 16
27+
#define OPSMAX 1
2728

29+
static int semid;
30+
31+
static void sig_handler( int sig_no )
32+
{
33+
union semun arg;
34+
int i = semctl( semid, 0, GETNCNT, arg );
35+
if( i == -1 ) perror( "semctl" );
36+
else printf( "semval = %d\n", i );
37+
}
2838

2939
int main( int argc, char **argv )
3040
{
@@ -34,7 +44,7 @@ int main( int argc, char **argv )
3444
int nsems = SEMMAX;
3545
int semflg = 0;
3646
int unlink = 0;
37-
int semid, i;
47+
int i;
3848
struct sembuf sops[OPSMAX];
3949
u_short array[SEMMAX];
4050
union semun arg;
@@ -67,8 +77,11 @@ int main( int argc, char **argv )
6777
exit( semid );
6878
}
6979

80+
/* test signal interrupts */
81+
signal( SIGTERM, sig_handler );
82+
7083
do {
71-
printf( "(-)sem_op, (+)sem_op, (G)ETVAL, (S)ETVAL, GET(P)ID, GET(A)LL, SETA(L)L, e(x)it: " );
84+
printf( "(-)sem_op, (+)sem_op, (G)ETVAL, (S)ETVAL, GET(P)ID, GET(A)LL, SETA(L)L, GET(N)CNT, GET(Z)CNT, e(x)it: " );
7285
scanf( "%s", s );
7386
switch( s[0] ) {
7487
case '-':
@@ -122,6 +135,20 @@ int main( int argc, char **argv )
122135
}
123136
if( semctl( semid, 0, SETALL, arg ) == -1 )perror( "semctl" );
124137
break;
138+
139+
case 'N':
140+
case 'n':
141+
i = semctl( semid, 0, GETNCNT, arg );
142+
if( i == -1 ) perror( "semctl" );
143+
else printf( "semval = %d\n", i );
144+
break;
145+
146+
case 'Z':
147+
case 'z':
148+
i = semctl( semid, 0, GETZCNT, arg );
149+
if( i == -1 ) perror( "semctl" );
150+
else printf( "semval = %d\n", i );
151+
break;
125152
}
126153
}
127154
while( s[0] != 'x' );

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