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 * Copyright 2013 Voxer Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* 28 * XXX Hack: Force the use of sys/exec_elf.h, not elfdefinitions.h. 29 * Why? 30 * 31 * - sys/dtrace.h is needed because (XXX why?). 32 * => sys/dtrace.h pulls in sys/ctf_api.h 33 * => which pulls in sys/elf.h 34 * => which pulls in elfdefinitions.h (XXX should it?) 35 * 36 * - link.h is needed for Link_map. 37 * => link.h pulls in link_elf.h 38 * => which pulls in sys/exec_elf.h 39 * 40 * But elfdefinitions.h and sys/exec_elf.h collide over most basic ELF 41 * definitions. Since we don't need elfdefinitions.h otherwise, prefer 42 * sys/exec_elf.h. 43 */ 44 #define _SYS_ELFDEFINITIONS_H_ 45 46 #include <unistd.h> 47 #include <fcntl.h> 48 #include <dlfcn.h> 49 #include <link.h> 50 #include <sys/dtrace.h> 51 #include <sys/ioctl.h> 52 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <errno.h> 58 #include <libelf.h> 59 60 /* 61 * In Solaris 10 GA, the only mechanism for communicating helper information 62 * is through the DTrace helper pseudo-device node in /devices; there is 63 * no /dev link. Because of this, USDT providers and helper actions don't 64 * work inside of non-global zones. This issue was addressed by adding 65 * the /dev and having this initialization code use that /dev link. If the 66 * /dev link doesn't exist it falls back to looking for the /devices node 67 * as this code may be embedded in a binary which runs on Solaris 10 GA. 68 * 69 * Users may set the following environment variable to affect the way 70 * helper initialization takes place: 71 * 72 * DTRACE_DOF_INIT_DEBUG enable debugging output 73 * DTRACE_DOF_INIT_DISABLE disable helper loading 74 * DTRACE_DOF_INIT_DEVNAME set the path to the helper node 75 */ 76 77 static const char *devnamep = "/dev/dtrace/helper"; 78 #ifdef illumos 79 static const char *olddevname = "/devices/pseudo/dtrace@0:helper"; 80 #endif 81 82 static const char *modname; /* Name of this load object */ 83 static int gen; /* DOF helper generation */ 84 extern dof_hdr_t __SUNW_dof; /* DOF defined in the .SUNW_dof section */ 85 static boolean_t dof_init_debug = B_FALSE; /* From DTRACE_DOF_INIT_DEBUG */ 86 87 static void __printflike(2,3) 88 dbg_printf(int debug, const char *fmt, ...) 89 { 90 va_list ap; 91 92 if (debug && !dof_init_debug) 93 return; 94 95 va_start(ap, fmt); 96 97 if (modname == NULL) 98 (void) fprintf(stderr, "dtrace DOF: "); 99 else 100 (void) fprintf(stderr, "dtrace DOF %s: ", modname); 101 102 (void) vfprintf(stderr, fmt, ap); 103 104 if (fmt[strlen(fmt) - 1] != '\n') 105 (void) fprintf(stderr, ": %s\n", strerror(errno)); 106 107 va_end(ap); 108 } 109 110 #ifdef illumos 111 #pragma init(dtrace_dof_init) 112 #else 113 static void dtrace_dof_init(void) __attribute__ ((constructor)); 114 #endif 115 116 static void 117 dtrace_dof_init(void) 118 { 119 dof_hdr_t *dof = &__SUNW_dof; 120 #ifdef _LP64 121 Elf64_Ehdr *elf; 122 #else 123 Elf32_Ehdr *elf; 124 #endif 125 dof_helper_t dh; 126 Link_map *lmp = NULL; 127 #ifdef illumos 128 Lmid_t lmid; 129 #else 130 u_long lmid = 0; 131 #endif 132 int fd; 133 const char *p; 134 135 if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL) 136 return; 137 138 if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL) 139 dof_init_debug = B_TRUE; 140 141 if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) { 142 dbg_printf(1, "couldn't discover module name or address\n"); 143 return; 144 } 145 146 #ifdef illumos 147 if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) { 148 dbg_printf(1, "couldn't discover link map ID\n"); 149 return; 150 } 151 #endif 152 153 if ((modname = strrchr(lmp->l_name, '/')) == NULL) 154 modname = lmp->l_name; 155 else 156 modname++; 157 158 if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 || 159 dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 || 160 dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 || 161 dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) { 162 dbg_printf(0, ".SUNW_dof section corrupt\n"); 163 return; 164 } 165 166 elf = (void *)lmp->l_addr; 167 168 dh.dofhp_dof = (uintptr_t)dof; 169 dh.dofhp_addr = elf && elf->e_type == ET_DYN ? (uintptr_t) lmp->l_addr : 0; 170 #if defined(__FreeBSD__) || defined(__NetBSD__) 171 dh.dofhp_pid = getpid(); 172 #endif 173 174 if (lmid == 0) { 175 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 176 "%s", modname); 177 } else { 178 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 179 "LM%lu`%s", lmid, modname); 180 } 181 182 if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL) 183 devnamep = p; 184 185 if ((fd = open64(devnamep, O_RDWR)) < 0) { 186 dbg_printf(1, "failed to open helper device %s", devnamep); 187 #ifdef illumos 188 /* 189 * If the device path wasn't explicitly set, try again with 190 * the old device path. 191 */ 192 if (p != NULL) 193 return; 194 195 devnamep = olddevname; 196 197 if ((fd = open64(devnamep, O_RDWR)) < 0) { 198 dbg_printf(1, "failed to open helper device %s", devnamep); 199 return; 200 } 201 #else 202 return; 203 #endif 204 } 205 if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1) 206 dbg_printf(1, "DTrace ioctl failed for DOF at %p", dof); 207 else { 208 dbg_printf(1, "DTrace ioctl succeeded for DOF at %p\n", dof); 209 #if defined(__FreeBSD__) || defined(__NetBSD__) 210 gen = dh.dofhp_gen; 211 #endif 212 } 213 214 (void) close(fd); 215 } 216 217 #ifdef illumos 218 #pragma fini(dtrace_dof_fini) 219 #else 220 static void dtrace_dof_fini(void) __attribute__ ((destructor)); 221 #endif 222 223 static void 224 dtrace_dof_fini(void) 225 { 226 int fd; 227 228 if ((fd = open64(devnamep, O_RDWR)) < 0) { 229 dbg_printf(1, "failed to open helper device %s", devnamep); 230 return; 231 } 232 233 if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, &gen)) == -1) 234 dbg_printf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen); 235 else 236 dbg_printf(1, "DTrace ioctl removed DOF (%d)\n", gen); 237 238 (void) close(fd); 239 } 240