1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include "lint.h" 30 #include <libc.h> 31 #include <fcntl.h> 32 #include <stdlib.h> 33 #include <unistd.h> 34 #include <sys/types.h> 35 #include <sys/stat.h> 36 #include <sys/auxv.h> 37 #include <mtlib.h> 38 #include <thread.h> 39 #include <synch.h> 40 #include <atomic.h> 41 42 static mutex_t auxlock = DEFAULTMUTEX; 43 44 /* 45 * Get auxiliary entry. 46 * Returns pointer to entry, or 0 if entry does not exist. 47 */ 48 static auxv_t * 49 _getaux(int type) 50 { 51 static auxv_t *auxb = NULL; 52 static size_t nauxv = 0; 53 ssize_t i; 54 55 /* 56 * The first time through, read the initial aux vector that was 57 * passed to the process at exec(2). Only do this once. 58 */ 59 if (auxb == NULL) { 60 lmutex_lock(&auxlock); 61 if (auxb == NULL) { 62 struct stat statb; 63 auxv_t *buf = NULL; 64 int fd; 65 66 if ((fd = open("/proc/self/auxv", O_RDONLY)) != -1 && 67 fstat(fd, &statb) != -1) 68 buf = libc_malloc( 69 statb.st_size + sizeof (auxv_t)); 70 71 if (buf != NULL) { 72 i = read(fd, buf, statb.st_size); 73 if (i != -1) { 74 nauxv = i / sizeof (auxv_t); 75 buf[nauxv].a_type = AT_NULL; 76 } else { 77 libc_free(buf); 78 buf = NULL; 79 } 80 } 81 82 if (fd != -1) 83 (void) close(fd); 84 85 membar_producer(); 86 auxb = buf; 87 } 88 lmutex_unlock(&auxlock); 89 } 90 membar_consumer(); 91 92 /* 93 * Scan the auxiliary entries looking for the required type. 94 */ 95 for (i = 0; i < nauxv; i++) 96 if (auxb[i].a_type == type) 97 return (&auxb[i]); 98 99 /* 100 * No auxiliary array (static executable) or entry not found. 101 */ 102 return ((auxv_t *)0); 103 } 104 105 /* 106 * These two routines are utilities exported to the rest of libc. 107 */ 108 109 long 110 ___getauxval(int type) 111 { 112 auxv_t *auxp; 113 114 if ((auxp = _getaux(type)) != (auxv_t *)0) 115 return (auxp->a_un.a_val); 116 return (0); 117 } 118 119 void * 120 ___getauxptr(int type) 121 { 122 auxv_t *auxp; 123 124 if ((auxp = _getaux(type)) != (auxv_t *)0) 125 return (auxp->a_un.a_ptr); 126 return (0); 127 } 128