1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * CDDL HEADER START 3*0Sstevel@tonic-gate * 4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*0Sstevel@tonic-gate * with the License. 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*0Sstevel@tonic-gate * See the License for the specific language governing permissions 12*0Sstevel@tonic-gate * and limitations under the License. 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*0Sstevel@tonic-gate * 20*0Sstevel@tonic-gate * CDDL HEADER END 21*0Sstevel@tonic-gate */ 22*0Sstevel@tonic-gate /* 23*0Sstevel@tonic-gate * Copyright 1998-2003 Sun Microsystems, Inc. All rights reserved. 24*0Sstevel@tonic-gate * Use is subject to license terms. 25*0Sstevel@tonic-gate */ 26*0Sstevel@tonic-gate 27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 28*0Sstevel@tonic-gate 29*0Sstevel@tonic-gate /* 30*0Sstevel@tonic-gate * This file contains functions that enables the rpc library to synchronize 31*0Sstevel@tonic-gate * between various threads while they compete for a particular file descriptor. 32*0Sstevel@tonic-gate */ 33*0Sstevel@tonic-gate 34*0Sstevel@tonic-gate #include "mt.h" 35*0Sstevel@tonic-gate #include "rpc_mt.h" 36*0Sstevel@tonic-gate #include <rpc/rpc.h> 37*0Sstevel@tonic-gate #include <rpc/trace.h> 38*0Sstevel@tonic-gate #include <errno.h> 39*0Sstevel@tonic-gate #include <sys/poll.h> 40*0Sstevel@tonic-gate #include <syslog.h> 41*0Sstevel@tonic-gate #include <sys/types.h> 42*0Sstevel@tonic-gate #include <stdlib.h> 43*0Sstevel@tonic-gate #include <unistd.h> 44*0Sstevel@tonic-gate 45*0Sstevel@tonic-gate /* 46*0Sstevel@tonic-gate * A block holds an array of maxBlockSize cell and associated recursive locks 47*0Sstevel@tonic-gate */ 48*0Sstevel@tonic-gate 49*0Sstevel@tonic-gate #define CELLTBLSZ 1024 50*0Sstevel@tonic-gate 51*0Sstevel@tonic-gate typedef struct rpcfd_block { 52*0Sstevel@tonic-gate struct rpcfd_block *next; /* Next Block */ 53*0Sstevel@tonic-gate struct rpcfd_block *prev; /* prev Block */ 54*0Sstevel@tonic-gate int end; /* fd of last lock in the list */ 55*0Sstevel@tonic-gate mutex_t lock[CELLTBLSZ]; /* recursive locks */ 56*0Sstevel@tonic-gate } rpcfd_block_t; 57*0Sstevel@tonic-gate 58*0Sstevel@tonic-gate mutex_t rpc_fd_list_lock = DEFAULTMUTEX; /* protects list manipulation */ 59*0Sstevel@tonic-gate 60*0Sstevel@tonic-gate /* Following functions create and manipulates the dgfd lock object */ 61*0Sstevel@tonic-gate 62*0Sstevel@tonic-gate static mutex_t *search(const void *handle, int fd); 63*0Sstevel@tonic-gate static rpcfd_block_t *create_block(const void *handle, int fd); 64*0Sstevel@tonic-gate 65*0Sstevel@tonic-gate void * 66*0Sstevel@tonic-gate rpc_fd_init(void) 67*0Sstevel@tonic-gate { 68*0Sstevel@tonic-gate /* 69*0Sstevel@tonic-gate * Create first chunk of CELLTBLSZ 70*0Sstevel@tonic-gate * (No lock is required for initial creation.) 71*0Sstevel@tonic-gate */ 72*0Sstevel@tonic-gate return (create_block(NULL, 0)); 73*0Sstevel@tonic-gate } 74*0Sstevel@tonic-gate 75*0Sstevel@tonic-gate /* 76*0Sstevel@tonic-gate * If rpc_fd_lock() fails to acquire a lock, it returns non-zero (ENOMEM). 77*0Sstevel@tonic-gate * (The operation can only fail due to a malloc() failure.) 78*0Sstevel@tonic-gate * The caller of rpc_fd_lock() must call rpc_fd_unlock() even if 79*0Sstevel@tonic-gate * rpc_fd_lock() failed. This keeps _sigoff() and _sigon() balanced. 80*0Sstevel@tonic-gate * 81*0Sstevel@tonic-gate * If search() and create_block() fail for rpc_fd_lock(), then search() 82*0Sstevel@tonic-gate * will fail for rpc_fd_unlock(), so mutex_lock() and mutex_unlock() 83*0Sstevel@tonic-gate * calls will be balanced. In any case, since the mutex is marked 84*0Sstevel@tonic-gate * LOCK_ERRORCHECK, an additional mutex_unlock() does nothing. 85*0Sstevel@tonic-gate */ 86*0Sstevel@tonic-gate int 87*0Sstevel@tonic-gate rpc_fd_lock(const void *handle, int fd) 88*0Sstevel@tonic-gate { 89*0Sstevel@tonic-gate mutex_t *mp; 90*0Sstevel@tonic-gate rpcfd_block_t *p; 91*0Sstevel@tonic-gate 92*0Sstevel@tonic-gate _sigoff(); 93*0Sstevel@tonic-gate (void) mutex_lock(&rpc_fd_list_lock); 94*0Sstevel@tonic-gate mp = search(handle, fd); 95*0Sstevel@tonic-gate if (mp == NULL) { 96*0Sstevel@tonic-gate p = create_block(handle, fd); 97*0Sstevel@tonic-gate if (p != NULL) 98*0Sstevel@tonic-gate mp = &p->lock[fd % CELLTBLSZ]; 99*0Sstevel@tonic-gate } 100*0Sstevel@tonic-gate (void) mutex_unlock(&rpc_fd_list_lock); 101*0Sstevel@tonic-gate if (mp == NULL) 102*0Sstevel@tonic-gate return (ENOMEM); 103*0Sstevel@tonic-gate (void) mutex_lock(mp); 104*0Sstevel@tonic-gate return (0); 105*0Sstevel@tonic-gate } 106*0Sstevel@tonic-gate 107*0Sstevel@tonic-gate void 108*0Sstevel@tonic-gate rpc_fd_unlock(const void *handle, int fd) 109*0Sstevel@tonic-gate { 110*0Sstevel@tonic-gate mutex_t *mp; 111*0Sstevel@tonic-gate 112*0Sstevel@tonic-gate (void) mutex_lock(&rpc_fd_list_lock); 113*0Sstevel@tonic-gate mp = search(handle, fd); 114*0Sstevel@tonic-gate (void) mutex_unlock(&rpc_fd_list_lock); 115*0Sstevel@tonic-gate if (mp != NULL) 116*0Sstevel@tonic-gate (void) mutex_unlock(mp); 117*0Sstevel@tonic-gate _sigon(); 118*0Sstevel@tonic-gate } 119*0Sstevel@tonic-gate 120*0Sstevel@tonic-gate static rpcfd_block_t * 121*0Sstevel@tonic-gate create_block(const void *handle, int fd) 122*0Sstevel@tonic-gate { 123*0Sstevel@tonic-gate rpcfd_block_t *l, *lprev; 124*0Sstevel@tonic-gate rpcfd_block_t *p; 125*0Sstevel@tonic-gate int i; 126*0Sstevel@tonic-gate 127*0Sstevel@tonic-gate p = malloc(sizeof (rpcfd_block_t)); 128*0Sstevel@tonic-gate if (p == NULL) 129*0Sstevel@tonic-gate return (NULL); 130*0Sstevel@tonic-gate 131*0Sstevel@tonic-gate for (i = 0; i < CELLTBLSZ; i++) { 132*0Sstevel@tonic-gate (void) mutex_init(&p->lock[i], 133*0Sstevel@tonic-gate USYNC_THREAD | LOCK_RECURSIVE | LOCK_ERRORCHECK, NULL); 134*0Sstevel@tonic-gate } 135*0Sstevel@tonic-gate p->end = (((fd + CELLTBLSZ) / CELLTBLSZ) * CELLTBLSZ) - 1; 136*0Sstevel@tonic-gate lprev = NULL; 137*0Sstevel@tonic-gate for (l = (rpcfd_block_t *)handle; l; l = l->next) { 138*0Sstevel@tonic-gate lprev = l; 139*0Sstevel@tonic-gate if (fd < l->end) 140*0Sstevel@tonic-gate break; 141*0Sstevel@tonic-gate } 142*0Sstevel@tonic-gate 143*0Sstevel@tonic-gate p->next = l; 144*0Sstevel@tonic-gate p->prev = lprev; 145*0Sstevel@tonic-gate if (lprev) 146*0Sstevel@tonic-gate lprev->next = p; 147*0Sstevel@tonic-gate if (l) 148*0Sstevel@tonic-gate l->prev = p; 149*0Sstevel@tonic-gate 150*0Sstevel@tonic-gate return (p); 151*0Sstevel@tonic-gate } 152*0Sstevel@tonic-gate 153*0Sstevel@tonic-gate /* 154*0Sstevel@tonic-gate * Called with rpc_fd_list_lock held. 155*0Sstevel@tonic-gate */ 156*0Sstevel@tonic-gate static mutex_t * 157*0Sstevel@tonic-gate search(const void *handle, int fd) 158*0Sstevel@tonic-gate { 159*0Sstevel@tonic-gate rpcfd_block_t *p; 160*0Sstevel@tonic-gate 161*0Sstevel@tonic-gate for (p = (rpcfd_block_t *)handle; p; p = p->next) { 162*0Sstevel@tonic-gate if (fd <= p->end) 163*0Sstevel@tonic-gate return (&p->lock[fd % CELLTBLSZ]); 164*0Sstevel@tonic-gate } 165*0Sstevel@tonic-gate 166*0Sstevel@tonic-gate return (NULL); 167*0Sstevel@tonic-gate } 168