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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 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 <unistd.h> 30 #include <fcntl.h> 31 #include <dlfcn.h> 32 #include <link.h> 33 #include <sys/dtrace.h> 34 35 #include <stdarg.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <errno.h> 40 41 /* 42 * In Solaris 10 GA, the only mechanism for communicating helper information 43 * is through the DTrace helper pseudo-device node in /devices; there is 44 * no /dev link. Because of this, USDT providers and helper actions don't 45 * work inside of non-global zones. This issue was addressed by adding 46 * the /dev and having this initialization code use that /dev link. If the 47 * /dev link doesn't exist it falls back to looking for the /devices node 48 * as this code may be embedded in a binary which runs on Solaris 10 GA. 49 * 50 * Users may set the following environment variable to affect the way 51 * helper initialization takes place: 52 * 53 * DTRACE_DOF_INIT_DEBUG enable debugging output 54 * DTRACE_DOF_INIT_DISABLE disable helper loading 55 * DTRACE_DOF_INIT_DEVNAME set the path to the helper node 56 */ 57 58 static const char *devnamep = "/dev/dtrace/helper"; 59 static const char *olddevname = "/devices/pseudo/dtrace@0:helper"; 60 61 static const char *modname; /* Name of this load object */ 62 static int gen; /* DOF helper generation */ 63 extern dof_hdr_t __SUNW_dof; /* DOF defined in the .SUNW_dof section */ 64 65 static void 66 dprintf(int debug, const char *fmt, ...) 67 { 68 va_list ap; 69 70 if (debug && getenv("DTRACE_DOF_INIT_DEBUG") == NULL) 71 return; 72 73 va_start(ap, fmt); 74 75 if (modname == NULL) 76 (void) fprintf(stderr, "dtrace DOF: "); 77 else 78 (void) fprintf(stderr, "dtrace DOF %s: ", modname); 79 80 (void) vfprintf(stderr, fmt, ap); 81 82 if (fmt[strlen(fmt) - 1] != '\n') 83 (void) fprintf(stderr, ": %s\n", strerror(errno)); 84 85 va_end(ap); 86 } 87 88 #if defined(sun) 89 #pragma init(dtrace_dof_init) 90 #else 91 static void dtrace_dof_init(void) __attribute__ ((constructor)); 92 #endif 93 94 static void 95 dtrace_dof_init(void) 96 { 97 dof_hdr_t *dof = &__SUNW_dof; 98 #ifdef _LP64 99 Elf64_Ehdr *elf; 100 #else 101 Elf32_Ehdr *elf; 102 #endif 103 dof_helper_t dh; 104 #if defined(sun) 105 Link_map *lmp; 106 Lmid_t lmid; 107 #else 108 struct link_map *lmp; 109 u_long lmid = 0; 110 #endif 111 int fd; 112 const char *p; 113 114 if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL) 115 return; 116 117 if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) { 118 dprintf(1, "couldn't discover module name or address\n"); 119 return; 120 } 121 122 #if defined(sun) 123 if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) { 124 dprintf(1, "couldn't discover link map ID\n"); 125 return; 126 } 127 #endif 128 129 if ((modname = strrchr(lmp->l_name, '/')) == NULL) 130 modname = lmp->l_name; 131 else 132 modname++; 133 134 if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 || 135 dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 || 136 dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 || 137 dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) { 138 dprintf(0, ".SUNW_dof section corrupt\n"); 139 return; 140 } 141 142 elf = (void *)lmp->l_addr; 143 144 dh.dofhp_dof = (uintptr_t)dof; 145 dh.dofhp_addr = elf->e_type == ET_DYN ? (uintptr_t) lmp->l_addr : 0; 146 147 if (lmid == 0) { 148 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 149 "%s", modname); 150 } else { 151 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 152 "LM%lu`%s", lmid, modname); 153 } 154 155 if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL) 156 devnamep = p; 157 158 if ((fd = open64(devnamep, O_RDWR)) < 0) { 159 dprintf(1, "failed to open helper device %s", devnamep); 160 161 /* 162 * If the device path wasn't explicitly set, try again with 163 * the old device path. 164 */ 165 if (p != NULL) 166 return; 167 168 devnamep = olddevname; 169 170 if ((fd = open64(devnamep, O_RDWR)) < 0) { 171 dprintf(1, "failed to open helper device %s", devnamep); 172 return; 173 } 174 } 175 176 if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1) 177 dprintf(1, "DTrace ioctl failed for DOF at %p", dof); 178 else 179 dprintf(1, "DTrace ioctl succeeded for DOF at %p\n", dof); 180 181 (void) close(fd); 182 } 183 184 #if defined(sun) 185 #pragma fini(dtrace_dof_fini) 186 #else 187 static void dtrace_dof_fini(void) __attribute__ ((destructor)); 188 #endif 189 190 static void 191 dtrace_dof_fini(void) 192 { 193 int fd; 194 195 if ((fd = open64(devnamep, O_RDWR)) < 0) { 196 dprintf(1, "failed to open helper device %s", devnamep); 197 return; 198 } 199 200 if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, gen)) == -1) 201 dprintf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen); 202 else 203 dprintf(1, "DTrace ioctl removed DOF (%d)\n", gen); 204 205 (void) close(fd); 206 } 207