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 55 static const char *devnamep = "/dev/dtrace/helper"; 56 static const char *olddevname = "/devices/pseudo/dtrace@0:helper"; 57 58 static const char *modname; /* Name of this load object */ 59 static int gen; /* DOF helper generation */ 60 extern dof_hdr_t __SUNW_dof; /* DOF defined in the .SUNW_dof section */ 61 static boolean_t dof_init_debug = B_FALSE; /* From DTRACE_DOF_INIT_DEBUG */ 62 63 static void 64 dprintf(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 #if defined(sun) 87 #pragma init(dtrace_dof_init) 88 #else 89 static void dtrace_dof_init(void) __attribute__ ((constructor)); 90 #endif 91 92 static void 93 dtrace_dof_init(void) 94 { 95 dof_hdr_t *dof = &__SUNW_dof; 96 #ifdef _LP64 97 Elf64_Ehdr *elf; 98 #else 99 Elf32_Ehdr *elf; 100 #endif 101 dof_helper_t dh; 102 #if defined(sun) 103 Link_map *lmp; 104 Lmid_t lmid; 105 #else 106 struct link_map *lmp; 107 u_long lmid = 0; 108 #endif 109 int fd; 110 const char *p; 111 112 if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL) 113 return; 114 115 if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL) 116 dof_init_debug = B_TRUE; 117 118 if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) { 119 dprintf(1, "couldn't discover module name or address\n"); 120 return; 121 } 122 123 #if defined(sun) 124 if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) { 125 dprintf(1, "couldn't discover link map ID\n"); 126 return; 127 } 128 #endif 129 130 if ((modname = strrchr(lmp->l_name, '/')) == NULL) 131 modname = lmp->l_name; 132 else 133 modname++; 134 135 if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 || 136 dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 || 137 dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 || 138 dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) { 139 dprintf(0, ".SUNW_dof section corrupt\n"); 140 return; 141 } 142 143 elf = (void *)lmp->l_addr; 144 145 dh.dofhp_dof = (uintptr_t)dof; 146 dh.dofhp_addr = elf->e_type == ET_DYN ? (uintptr_t) lmp->l_addr : 0; 147 148 if (lmid == 0) { 149 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 150 "%s", modname); 151 } else { 152 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod), 153 "LM%lu`%s", lmid, modname); 154 } 155 156 if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL) 157 devnamep = p; 158 159 if ((fd = open64(devnamep, O_RDWR)) < 0) { 160 dprintf(1, "failed to open helper device %s", devnamep); 161 162 /* 163 * If the device path wasn't explicitly set, try again with 164 * the old device path. 165 */ 166 if (p != NULL) 167 return; 168 169 devnamep = olddevname; 170 171 if ((fd = open64(devnamep, O_RDWR)) < 0) { 172 dprintf(1, "failed to open helper device %s", devnamep); 173 return; 174 } 175 } 176 177 if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1) 178 dprintf(1, "DTrace ioctl failed for DOF at %p", dof); 179 else 180 dprintf(1, "DTrace ioctl succeeded for DOF at %p\n", dof); 181 182 (void) close(fd); 183 } 184 185 #if defined(sun) 186 #pragma fini(dtrace_dof_fini) 187 #else 188 static void dtrace_dof_fini(void) __attribute__ ((destructor)); 189 #endif 190 191 static void 192 dtrace_dof_fini(void) 193 { 194 int fd; 195 196 if ((fd = open64(devnamep, O_RDWR)) < 0) { 197 dprintf(1, "failed to open helper device %s", devnamep); 198 return; 199 } 200 201 if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, gen)) == -1) 202 dprintf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen); 203 else 204 dprintf(1, "DTrace ioctl removed DOF (%d)\n", gen); 205 206 (void) close(fd); 207 } 208