mirror of https://github.com/postgres/postgres
Tom Lane
24 years ago
parent
3e48c66136
commit
8df5625966
@ -1,389 +0,0 @@ |
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/*-------------------------------------------------------------------------
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* |
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* sem.c |
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* System V Semaphore Emulation |
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* |
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* Copyright (c) 1999, repas AEG Automation GmbH |
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* |
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* 2000-12-1 pmb@mac.com |
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* - changed from anonymous to named semaphores for darwin |
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* - this required changing sem_info from containig an array of sem_t to an array of sem_t* |
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* |
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* IDENTIFICATION |
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* $Header: /cvsroot/pgsql/src/backend/port/darwin/Attic/sem.c,v 1.5 2001/10/25 05:49:40 momjian Exp $ |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#include "postgres.h" |
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#include <errno.h> |
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#include <semaphore.h> |
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#include <string.h> |
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#include <sys/types.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <sys/mman.h> |
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#include "miscadmin.h" |
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#include "storage/ipc.h" |
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#include "storage/proc.h" |
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#include "port/darwin/sem.h" |
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#define SEMMAX IPC_NMAXSEM |
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#define OPMAX 8 |
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#define MODE 0700 |
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#define SHM_INFO_NAME "SysV_Sem_Info" |
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#define SEM_NAME "/pgsql-darwin" |
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struct pending_ops |
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{ |
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int op[OPMAX]; /* array of pending operations */ |
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int idx; /* index of first free array member */ |
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}; |
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struct sem_set_info |
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{ |
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key_t key; |
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int nsems; |
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sem_t *sem[SEMMAX]; /* array of POSIX semaphores */ |
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struct sem semV[SEMMAX]; /* array of System V semaphore structures */ |
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struct pending_ops pendingOps[SEMMAX]; /* array of pending
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* operations */ |
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}; |
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struct sem_info |
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{ |
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sem_t *sem; |
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int nsets; |
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/* there are actually nsets of these: */ |
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struct sem_set_info set[1]; /* VARIABLE LENGTH ARRAY */ |
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}; |
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static struct sem_info *SemInfo = (struct sem_info *) - 1; |
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int |
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semctl(int semid, int semnum, int cmd, /* ... */ union semun arg) |
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{ |
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int r = 0; |
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sem_wait(SemInfo->sem); |
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if (semid < 0 || semid >= SemInfo->nsets || |
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semnum < 0 || semnum >= SemInfo->set[semid].nsems) |
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{ |
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sem_post(SemInfo->sem); |
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errno = EINVAL; |
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return -1; |
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} |
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switch (cmd) |
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{ |
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case GETNCNT: |
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r = SemInfo->set[semid].semV[semnum].semncnt; |
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break; |
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case GETPID: |
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r = SemInfo->set[semid].semV[semnum].sempid; |
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break; |
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case GETVAL: |
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r = SemInfo->set[semid].semV[semnum].semval; |
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break; |
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case GETALL: |
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for (semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++) |
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arg.array[semnum] = SemInfo->set[semid].semV[semnum].semval; |
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break; |
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case SETVAL: |
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SemInfo->set[semid].semV[semnum].semval = arg.val; |
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break; |
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case SETALL: |
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for (semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++) |
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SemInfo->set[semid].semV[semnum].semval = arg.array[semnum]; |
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break; |
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case GETZCNT: |
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r = SemInfo->set[semid].semV[semnum].semzcnt; |
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break; |
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case IPC_RMID: |
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for (semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++) |
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{ |
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if (sem_close(SemInfo->set[semid].sem[semnum]) == -1) |
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r = -1; |
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} |
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SemInfo->set[semid].key = -1; |
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SemInfo->set[semid].nsems = 0; |
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break; |
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default: |
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sem_post(SemInfo->sem); |
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errno = EINVAL; |
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return -1; |
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} |
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sem_post(SemInfo->sem); |
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return r; |
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} |
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int |
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semget(key_t key, int nsems, int semflg) |
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{ |
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int fd, |
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semid, |
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semnum, |
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nsets; |
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int exist = 0; |
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Size sem_info_size; |
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char semname[64]; |
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if (nsems < 0 || nsems > SEMMAX) |
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{ |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin semget aborting because nsems out of range. (%d)\n", nsems); |
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#endif |
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errno = EINVAL; |
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return -1; |
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} |
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/* open and map shared memory */ |
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if (SemInfo == (struct sem_info *) - 1) |
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{ |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin initializing shared mem for semaphore shim.\n"); |
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#endif |
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/* test if the shared memory already exists */ |
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fd = shm_open(SHM_INFO_NAME, O_RDWR | O_CREAT | O_EXCL, MODE); |
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if (fd == -1 && errno == EEXIST) |
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{ |
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/* exist = 1; */ |
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shm_unlink(SHM_INFO_NAME); |
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fd = shm_open(SHM_INFO_NAME, O_RDWR | O_CREAT | O_EXCL, MODE); |
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} |
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if (fd == -1) |
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return fd; |
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shm_unlink(SHM_INFO_NAME); |
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/* The size may only be set once. Ignore errors. */ |
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nsets = PROC_SEM_MAP_ENTRIES(MaxBackends); |
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sem_info_size = sizeof(struct sem_info) + (nsets - 1) * sizeof(struct sem_set_info); |
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ftruncate(fd, sem_info_size); |
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SemInfo = mmap(NULL, sem_info_size, |
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PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); |
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if (SemInfo == MAP_FAILED) |
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return -1; |
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if (!exist) |
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{ |
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/* initialize shared memory */ |
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memset(SemInfo, 0, sem_info_size); |
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SemInfo->nsets = nsets; |
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for (semid = 0; semid < nsets; semid++) |
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SemInfo->set[semid].key = -1; |
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/* create semaphore for locking */ |
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sprintf(semname, "%s-map", SEM_NAME); |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin creating sem %s to cover shared mem.\n", semname); |
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#endif |
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SemInfo->sem = sem_open(semname, O_CREAT, semflg & 0777, 1); |
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sem_unlink(semname); |
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} |
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} |
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sem_wait(SemInfo->sem); |
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nsets = SemInfo->nsets; |
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if (key != IPC_PRIVATE) |
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{ |
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/* search existing element */ |
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semid = 0; |
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while (semid < nsets && SemInfo->set[semid].key != key) |
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semid++; |
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if (!(semflg & IPC_CREAT) && semid >= nsets) |
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{ |
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sem_post(SemInfo->sem); |
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errno = ENOENT; |
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return -1; |
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} |
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else if (semid < nsets) |
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{ |
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if (semflg & IPC_CREAT && semflg & IPC_EXCL) |
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{ |
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sem_post(SemInfo->sem); |
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errno = EEXIST; |
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return -1; |
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} |
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else |
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{ |
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if (nsems != 0 && SemInfo->set[semid].nsems < nsems) |
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{ |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin semget failed because if (nsems != 0 && SemInfo->set[semid].nsems < nsems) %d %d\n", |
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nsems, SemInfo->set[semid].nsems); |
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#endif |
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sem_post(SemInfo->sem); |
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errno = EINVAL; |
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return -1; |
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} |
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sem_post(SemInfo->sem); |
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return semid; |
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} |
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} |
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} |
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/* search first free element */ |
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semid = 0; |
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while (semid < nsets && SemInfo->set[semid].key != -1) |
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semid++; |
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if (semid >= nsets) |
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{ |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin semget failed because all keys were -1\n"); |
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#endif |
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sem_post(SemInfo->sem); |
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errno = ENOSPC; |
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return -1; |
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} |
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for (semnum = 0; semnum < nsems; semnum++) |
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{ |
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sprintf(semname, "%s-%d-%d", SEM_NAME, semid, semnum); |
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#ifdef DEBUG_IPC |
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fprintf(stderr, "darwin creating sem %s to cover set %d num %dm.\n", semname, semid, semnum); |
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#endif |
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SemInfo->set[semid].sem[semnum] = sem_open(semname, O_CREAT, semflg & 0777, 0); |
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sem_unlink(semname); |
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/* Currently sem_init always returns -1. */ |
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#ifdef NOT_USED |
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if (sem_init(&SemInfo->set[semid].sem[semnum], 1, 0) == -1) |
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{ |
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int semnum1; |
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for (semnum1 = 0; semnum1 < semnum; semnum1++) |
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sem_close(SemInfo->set[semid].sem[semnum1]); |
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sem_post(SemInfo->sem); |
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return -1; |
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} |
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#endif |
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} |
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SemInfo->set[semid].key = key; |
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SemInfo->set[semid].nsems = nsems; |
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sem_post(SemInfo->sem); |
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return semid; |
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} |
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int |
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semop(int semid, struct sembuf * sops, size_t nsops) |
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{ |
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int i, |
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r = 0, |
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r1, |
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errno1 = 0, |
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op; |
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sem_wait(SemInfo->sem); |
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if (semid < 0 || semid >= SemInfo->nsets) |
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{ |
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sem_post(SemInfo->sem); |
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errno = EINVAL; |
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return -1; |
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} |
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for (i = 0; i < nsops; i++) |
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{ |
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if ( /* sops[i].sem_num < 0 || */ sops[i].sem_num >= SemInfo->set[semid].nsems) |
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{ |
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sem_post(SemInfo->sem); |
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errno = EFBIG; |
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return -1; |
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} |
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} |
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for (i = 0; i < nsops; i++) |
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{ |
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if (sops[i].sem_op < 0) |
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{ |
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if (SemInfo->set[semid].semV[sops[i].sem_num].semval < -sops[i].sem_op) |
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{ |
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if (sops[i].sem_flg & IPC_NOWAIT) |
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{ |
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sem_post(SemInfo->sem); |
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errno = EAGAIN; |
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return -1; |
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} |
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SemInfo->set[semid].semV[sops[i].sem_num].semncnt++; |
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if (SemInfo->set[semid].pendingOps[sops[i].sem_num].idx >= OPMAX) |
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{ |
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/* pending operations array overflow */ |
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sem_post(SemInfo->sem); |
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errno = ERANGE; |
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return -1; |
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} |
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SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx++] = sops[i].sem_op; |
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/* suspend */ |
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sem_post(SemInfo->sem); /* avoid deadlock */ |
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r1 = sem_wait(SemInfo->set[semid].sem[sops[i].sem_num]); |
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sem_wait(SemInfo->sem); |
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if (r1) |
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{ |
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errno1 = errno; |
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r = r1; |
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/* remove pending operation */ |
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SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0; |
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} |
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else |
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SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op; |
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SemInfo->set[semid].semV[sops[i].sem_num].semncnt--; |
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} |
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else |
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SemInfo->set[semid].semV[sops[i].sem_num].semval -= -sops[i].sem_op; |
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} |
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else if (sops[i].sem_op > 0) |
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{ |
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SemInfo->set[semid].semV[sops[i].sem_num].semval += sops[i].sem_op; |
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op = sops[i].sem_op; |
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while (op > 0 && SemInfo->set[semid].pendingOps[sops[i].sem_num].idx > 0) |
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{ /* operations pending */ |
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if (SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx - 1] + op >= 0) |
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{ |
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/* unsuspend processes */ |
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if (sem_post(SemInfo->set[semid].sem[sops[i].sem_num])) |
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{ |
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errno1 = errno; |
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r = -1; |
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} |
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/* adjust pending operations */ |
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op += SemInfo->set[semid].pendingOps[sops[i].sem_num].op[--SemInfo->set[semid].pendingOps[sops[i].sem_num].idx]; |
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SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx] = 0; |
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} |
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else |
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{ |
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/* adjust pending operations */ |
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SemInfo->set[semid].pendingOps[sops[i].sem_num].op[SemInfo->set[semid].pendingOps[sops[i].sem_num].idx - 1] += op; |
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op = 0; |
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} |
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} |
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} |
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else |
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/* sops[i].sem_op == 0 */ |
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{ |
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/* not supported */ |
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sem_post(SemInfo->sem); |
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errno = ENOSYS; |
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return -1; |
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} |
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SemInfo->set[semid].semV[sops[i].sem_num].sempid = getpid(); |
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} |
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sem_post(SemInfo->sem); |
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errno = errno1; |
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return r; |
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} |
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