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> I have improved the System V semaphore emulation of the QNX4 port.

Browse Source 
Please
> apply the attached patch to
>
> backend/port/qnx4
>
> Andreas Kardos
>
This commit is contained in:
Bruce Momjian 2000-03-14 18:12:06 +00:00
parent e3fb902991
commit e02cde4b0a
3 changed files with 145 additions and 58 deletions
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125
src/backend/port/qnx4/sem.c
View File

@ -7,7 +7,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.c,v 1.1 1999/12/16 16:52:52 momjian Exp $ * $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.c,v 1.2 2000/03/14 18:12:06 momjian Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -21,23 +21,31 @@
#include <sys/mman.h> #include <sys/mman.h>
#include "postgres.h" #include "postgres.h"
#include "storage/ipc.h" #include "storage/ipc.h"
#include "storage/proc.h"
#include <sys/sem.h> #include <sys/sem.h>
#define SETMAX 32 #define SETMAX ((MAXBACKENDS + PROC_NSEMS_PER_SET - 1) / PROC_NSEMS_PER_SET)
#define SEMMAX 16 #define SEMMAX (PROC_NSEMS_PER_SET)
#define OPMAX 8
#define MODE 0777 #define MODE 0700
#define SHM_INFO_NAME "SysV_Sem_Info" #define SHM_INFO_NAME "SysV_Sem_Info"
struct pending_ops {
int op[OPMAX]; /* array of pending operations */
int idx; /* index of first free array member */
};
struct sem_info { struct sem_info {
sem_t sem; sem_t sem;
struct { struct {
key_t key; key_t key;
int nsems; int nsems;
sem_t sem[SEMMAX]; /* array of semaphores */ sem_t sem[SEMMAX]; /* array of POSIX semaphores */
pid_t pid[SEMMAX]; /* array of PIDs */ struct sem semV[SEMMAX]; /* array of System V semaphore structures */
struct pending_ops pendingOps[SEMMAX]; /* array of pending operations */
} set[SETMAX]; } set[SETMAX];
}; };
@ -46,7 +54,7 @@ static struct sem_info *SemInfo = ( struct sem_info * )-1;
int semctl( int semid, int semnum, int cmd, /*...*/union semun arg ) int semctl( int semid, int semnum, int cmd, /*...*/union semun arg )
{ {
int r; int r = 0;
sem_wait( &SemInfo->sem ); sem_wait( &SemInfo->sem );
@ -58,30 +66,38 @@ int semctl( int semid, int semnum, int cmd, /*...*/union semun arg )
} }
switch( cmd ) { switch( cmd ) {
case GETNCNT:
r = SemInfo->set[semid].semV[semnum].semncnt;
break;
case GETPID: case GETPID:
r = SemInfo->set[semid].pid[semnum]; r = SemInfo->set[semid].semV[semnum].sempid;
break; break;
case GETVAL: case GETVAL:
r = SemInfo->set[semid].sem[semnum].value; r = SemInfo->set[semid].semV[semnum].semval;
break; break;
case GETALL: case GETALL:
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
arg.array[semnum] = SemInfo->set[semid].sem[semnum].value; arg.array[semnum] = SemInfo->set[semid].semV[semnum].semval;
} }
break; break;
case SETVAL: case SETVAL:
SemInfo->set[semid].sem[semnum].value = arg.val; SemInfo->set[semid].semV[semnum].semval = arg.val;
break; break;
case SETALL: case SETALL:
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
SemInfo->set[semid].sem[semnum].value = arg.array[semnum]; SemInfo->set[semid].semV[semnum].semval = arg.array[semnum];
} }
break; break;
case GETZCNT:
r = SemInfo->set[semid].semV[semnum].semzcnt;
break;
case IPC_RMID: case IPC_RMID:
for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) {
if( sem_destroy( &SemInfo->set[semid].sem[semnum] ) == -1 ) { if( sem_destroy( &SemInfo->set[semid].sem[semnum] ) == -1 ) {
@ -121,12 +137,16 @@ int semget( key_t key, int nsems, int semflg )
exist = 1; exist = 1;
fd = shm_open( SHM_INFO_NAME, O_RDWR | O_CREAT, MODE ); fd = shm_open( SHM_INFO_NAME, O_RDWR | O_CREAT, MODE );
} }
if( fd == -1 ) return fd; if( fd == -1 ) {
return fd;
}
/* The size may only be set once. Ignore errors. */ /* The size may only be set once. Ignore errors. */
ltrunc( fd, sizeof( struct sem_info ), SEEK_SET ); ltrunc( fd, sizeof( struct sem_info ), SEEK_SET );
SemInfo = mmap( NULL, sizeof( struct sem_info ), SemInfo = mmap( NULL, sizeof( struct sem_info ),
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 ); PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 );
if( SemInfo == MAP_FAILED ) return -1; if( SemInfo == MAP_FAILED ) {
return -1;
}
if( !exist ) { if( !exist ) {
/* create semaphore for locking */ /* create semaphore for locking */
sem_init( &SemInfo->sem, 1, 1 ); sem_init( &SemInfo->sem, 1, 1 );
@ -196,12 +216,12 @@ int semget( key_t key, int nsems, int semflg )
sem_post( &SemInfo->sem ); sem_post( &SemInfo->sem );
return 0; return semid;
} }
int semop( int semid, struct sembuf *sops, size_t nsops ) int semop( int semid, struct sembuf *sops, size_t nsops )
{ {
int i, j, r = 0, r1, errno1 = 0; int i, r = 0, r1, errno1 = 0, op;
sem_wait( &SemInfo->sem ); sem_wait( &SemInfo->sem );
@ -220,38 +240,67 @@ int semop( int semid, struct sembuf *sops, size_t nsops )
for( i = 0; i < nsops; i++ ) { for( i = 0; i < nsops; i++ ) {
if( sops[i].sem_op < 0 ) { if( sops[i].sem_op < 0 ) {
if( sops[i].sem_flg & IPC_NOWAIT ) { if( SemInfo->set[semid].semV[sops[i].sem_num].semval < -sops[i].sem_op ) {
for( j = 0; j < -sops[i].sem_op; j++ ) { if( sops[i].sem_flg & IPC_NOWAIT ) {
if( sem_trywait( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) { sem_post( &SemInfo->sem );
errno1 = errno; errno = EAGAIN;
r = -1; return -1;
}
} }
SemInfo->set[semid].semV[sops[i].sem_num].semncnt++;
if( SemInfo->set[semid].pendingOps[sops[i].sem_num].idx >= OPMAX ) {
/* pending operations array overflow */
sem_post( &SemInfo->sem );
errno = ERANGE;
return -1;
}
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx++] = sops[i].sem_op;
/* suspend */
sem_post( &SemInfo->sem ); /* avoid deadlock */
r1 = sem_wait( &SemInfo->set[semid].sem[sops[i].sem_num] );
sem_wait( &SemInfo->sem );
if( r1 ) {
errno1 = errno;
r = r1;
/* remove pending operation */
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0;
}
else {
SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op;
}
SemInfo->set[semid].semV[sops[i].sem_num].semncnt--;
} }
else { else {
for( j = 0; j < -sops[i].sem_op; j++ ) { SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op;
sem_post( &SemInfo->sem ); /* avoid deadlock */
r1 = sem_wait( &SemInfo->set[semid].sem[sops[i].sem_num] );
sem_wait( &SemInfo->sem );
if( r1 ) {
errno1 = errno;
r = r1;
}
}
} }
} }
else if( sops[i].sem_op > 0 ) { else if( sops[i].sem_op > 0 ) {
for( j = 0; j < sops[i].sem_op; j++ ) { SemInfo->set[semid].semV[sops[i].sem_num].semval += sops[i].sem_op;
if( sem_post( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) { op = sops[i].sem_op;
errno1 = errno; while( op > 0 && SemInfo->set[semid].pendingOps[sops[i].sem_num].idx > 0 ) { /* operations pending */
r = -1; if( SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx-1] + op >= 0 ) {
/* unsuspend processes */
if( sem_post( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) {
errno1 = errno;
r = -1;
}
/* adjust pending operations */
op += SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx];
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0;
}
else {
/* adjust pending operations */
SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx-1] += op;
op = 0;
} }
} }
} }
else /* sops[i].sem_op == 0 */ { else /* sops[i].sem_op == 0 */ {
/* not supported */ /* not supported */
sem_post( &SemInfo->sem );
errno = ENOSYS;
return -1;
} }
SemInfo->set[semid].pid[sops[i].sem_num] = getpid( ); SemInfo->set[semid].semV[sops[i].sem_num].sempid = getpid( );
} }
sem_post( &SemInfo->sem ); sem_post( &SemInfo->sem );

41
src/backend/port/qnx4/sem.h
View File

@ -7,7 +7,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.h,v 1.1 1999/12/16 16:52:52 momjian Exp $ * $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/sem.h,v 1.2 2000/03/14 18:12:06 momjian Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -17,37 +17,48 @@
#include <sys/ipc.h> #include <sys/ipc.h>
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
/* /*
* Semctl Command Definitions. * Semctl Command Definitions.
*/ */
#define GETNCNT 3 /* get semncnt */ #define GETNCNT 3 /* get semncnt */
#define GETPID 4 /* get sempid */ #define GETPID 4 /* get sempid */
#define GETVAL 5 /* get semval */ #define GETVAL 5 /* get semval */
#define GETALL 6 /* get all semval's */ #define GETALL 6 /* get all semval's */
#define GETZCNT 7 /* get semzcnt */ #define GETZCNT 7 /* get semzcnt */
#define SETVAL 8 /* set semval */ #define SETVAL 8 /* set semval */
#define SETALL 9 /* set all semval's */ #define SETALL 9 /* set all semval's */
/* /*
* User semaphore template for semop system calls. * There is one semaphore structure for each semaphore in the system.
*/
struct sem {
ushort_t semval; /* semaphore text map address */
pid_t sempid; /* pid of last operation */
ushort_t semncnt; /* # awaiting semval > cval */
ushort_t semzcnt; /* # awaiting semval = 0 */
};
/*
* User semaphore template for semop system calls.
*/ */
struct sembuf { struct sembuf {
ushort_t sem_num; /* semaphore # */ ushort_t sem_num; /* semaphore # */
short sem_op; /* semaphore operation */ short sem_op; /* semaphore operation */
short sem_flg; /* operation flags */ short sem_flg; /* operation flags */
}; };
extern int semctl( int semid, int semnum, int cmd, /*...*/union semun arg ); extern int semctl( int semid, int semnum, int cmd, /*...*/union semun arg );
extern int semget( key_t key, int nsems, int semflg ); extern int semget( key_t key, int nsems, int semflg );
extern int semop( int semid, struct sembuf *sops, size_t nsops ); extern int semop( int semid, struct sembuf *sops, size_t nsops );
#ifdef __cplusplus #ifdef __cplusplus
} }
#endif #endif

37
src/backend/port/qnx4/tstsem.c
View File

@ -7,12 +7,13 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/tstsem.c,v 1.1 1999/12/16 16:52:52 momjian Exp $ * $Header: /cvsroot/pgsql/src/backend/port/qnx4/Attic/tstsem.c,v 1.2 2000/03/14 18:12:06 momjian Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
#include <signal.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <unistd.h> #include <unistd.h>
@ -22,9 +23,18 @@
#include <sys/sem.h> #include <sys/sem.h>
#define SEMMAX 1 #define SEMMAX 16
#define OPSMAX 1 #define OPSMAX 1
static int semid;
static void sig_handler( int sig_no )
{
union semun arg;
int i = semctl( semid, 0, GETNCNT, arg );
if( i == -1 ) perror( "semctl" );
else printf( "semval = %d\n", i );
}
int main( int argc, char **argv ) int main( int argc, char **argv )
{ {
@ -34,7 +44,7 @@ int main( int argc, char **argv )
int nsems = SEMMAX; int nsems = SEMMAX;
int semflg = 0; int semflg = 0;
int unlink = 0; int unlink = 0;
int semid, i; int i;
struct sembuf sops[OPSMAX]; struct sembuf sops[OPSMAX];
u_short array[SEMMAX]; u_short array[SEMMAX];
union semun arg; union semun arg;
@ -67,8 +77,11 @@ int main( int argc, char **argv )
exit( semid ); exit( semid );
} }
/* test signal interrupts */
signal( SIGTERM, sig_handler );
do { do {
printf( "(-)sem_op, (+)sem_op, (G)ETVAL, (S)ETVAL, GET(P)ID, GET(A)LL, SETA(L)L, e(x)it: " ); 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: " );
scanf( "%s", s ); scanf( "%s", s );
switch( s[0] ) { switch( s[0] ) {
case '-': case '-':
@ -122,6 +135,20 @@ int main( int argc, char **argv )
} }
if( semctl( semid, 0, SETALL, arg ) == -1 )perror( "semctl" ); if( semctl( semid, 0, SETALL, arg ) == -1 )perror( "semctl" );
break; break;
case 'N':
case 'n':
i = semctl( semid, 0, GETNCNT, arg );
if( i == -1 ) perror( "semctl" );
else printf( "semval = %d\n", i );
break;
case 'Z':
case 'z':
i = semctl( semid, 0, GETZCNT, arg );
if( i == -1 ) perror( "semctl" );
else printf( "semval = %d\n", i );
break;
} }
} }
while( s[0] != 'x' ); while( s[0] != 'x' );