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 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26#include <unistd.h> 27#include <fcntl.h> 28#include <dlfcn.h> 29#include <link.h> 30#include <sys/dtrace.h> 31 32#include <stdarg.h> 33#include <stdio.h> 34#include <stdlib.h> 35#include <string.h> 36#include <errno.h> 37 38/* 39 * In Solaris 10 GA, the only mechanism for communicating helper information 40 * is through the DTrace helper pseudo-device node in /devices; there is 41 * no /dev link. Because of this, USDT providers and helper actions don't 42 * work inside of non-global zones. This issue was addressed by adding 43 * the /dev and having this initialization code use that /dev link. If the 44 * /dev link doesn't exist it falls back to looking for the /devices node 45 * as this code may be embedded in a binary which runs on Solaris 10 GA. 46 * 47 * Users may set the following environment variable to affect the way 48 * helper initialization takes place: 49 * 50 * DTRACE_DOF_INIT_DEBUG enable debugging output 51 * DTRACE_DOF_INIT_DISABLE disable helper loading 52 * DTRACE_DOF_INIT_DEVNAME set the path to the helper node 53 */ 54 55static const char *devname = "/dev/dtrace/helper"; 56static const char *olddevname = "/devices/pseudo/dtrace@0:helper"; 57 58static const char *modname; /* Name of this load object */ 59static int gen; /* DOF helper generation */ 60extern dof_hdr_t __SUNW_dof; /* DOF defined in the .SUNW_dof section */ 61static boolean_t dof_init_debug = B_FALSE; /* From DTRACE_DOF_INIT_DEBUG */ 62 63static void 64dprintf(int debug, const char *fmt, ...) 65{ 66 va_list ap; 67 68 if (debug && !dof_init_debug) 69 return; 70 71 va_start(ap, fmt); 72 73 if (modname == NULL) 74 (void) fprintf(stderr, "dtrace DOF: "); 75 else 76 (void) fprintf(stderr, "dtrace DOF %s: ", modname); 77 78 (void) vfprintf(stderr, fmt, ap); 79 80 if (fmt[strlen(fmt) - 1] != '\n') 81 (void) fprintf(stderr, ": %s\n", strerror(errno)); 82 83 va_end(ap); 84} 85 86#pragma init(dtrace_dof_init) 87static void 88dtrace_dof_init(void) 89{ 90 dof_hdr_t *dof = &__SUNW_dof; 91#ifdef _LP64 92 Elf64_Ehdr *elf; 93#else 94 Elf32_Ehdr *elf; 95#endif 96 dof_helper_t dh; 97 Link_map *lmp; 98 Lmid_t lmid; 99 int fd; 100 const char *p; 101 102 if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL) 103 return; 104 105 if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL) 106 dof_init_debug = B_TRUE; 107 108 if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) { 109 dprintf(1, "couldn't discover module name or address\n"); 110 return; 111 } 112 113 if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) { 114 dprintf(1, "couldn't discover link map ID\n"); 115 return; 116 } 117 118 if ((modname = strrchr(lmp->l_name, '/')) == NULL) 119 modname = lmp->l_name; 120 else 121 modname++; 122 123 if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 || 124 dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 || 125 dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 || 126 dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) { 127 dprintf(0, ".SUNW_dof section corrupt\n"); 128 return; 129 } 130 131 elf = (void *)lmp->l_addr; 132 133 dh.dofhp_dof = (uintptr_t)dof; 134 dh.dofhp_addr = elf->e_type == ET_DYN ? lmp->l_addr : 0; 135 136 if (lmid == 0) { 137 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 138 "%s", modname); 139 } else { 140 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 141 "LM%lu`%s", lmid, modname); 142 } 143 144 if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL) 145 devname = p; 146 147 if ((fd = open64(devname, O_RDWR)) < 0) { 148 dprintf(1, "failed to open helper device %s", devname); 149 150 /* 151 * If the device path wasn't explicitly set, try again with 152 * the old device path. 153 */ 154 if (p != NULL) 155 return; 156 157 devname = olddevname; 158 159 if ((fd = open64(devname, O_RDWR)) < 0) { 160 dprintf(1, "failed to open helper device %s", devname); 161 return; 162 } 163 } 164 165 if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1) 166 dprintf(1, "DTrace ioctl failed for DOF at %p", dof); 167 else 168 dprintf(1, "DTrace ioctl succeeded for DOF at %p\n", dof); 169 170 (void) close(fd); 171} 172 173#pragma fini(dtrace_dof_fini) 174static void 175dtrace_dof_fini(void) 176{ 177 int fd; 178 179 if ((fd = open64(devname, O_RDWR)) < 0) { 180 dprintf(1, "failed to open helper device %s", devname); 181 return; 182 } 183 184 if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, gen)) == -1) 185 dprintf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen); 186 else 187 dprintf(1, "DTrace ioctl removed DOF (%d)\n", gen); 188 189 (void) close(fd); 190} 191