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 /*
28 * Copyright (c) 2012 by Delphix. All rights reserved.
29 */
30
31 /*
32 * Common functions for helper provider loading both compiled into the
33 * executable via drti.o and dtrace(8) -G, and the libdaudit.so library.
34 */
35
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <stdarg.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43
44 #include <dlink.h>
45
46 /*
47 * In Solaris 10 GA, the only mechanism for communicating helper information
48 * is through the DTrace helper pseudo-device node in /devices; there is
49 * no /dev link. Because of this, USDT providers and helper actions don't
50 * work inside of non-global zones. This issue was addressed by adding
51 * the /dev and having this initialization code use that /dev link. If the
52 * /dev link doesn't exist it falls back to looking for the /devices node
53 * as this code may be embedded in a binary which runs on Solaris 10 GA.
54 */
55 const char *devname = "/dev/dtrace/helper";
56 static const char *olddevname = "/devices/pseudo/dtrace@0:helper";
57
58 static boolean_t dof_init_debug = B_FALSE;
59
60 void
dprintf(int debug,const char * fmt,...)61 dprintf(int debug, const char *fmt, ...)
62 {
63 va_list ap;
64
65 if (debug && !dof_init_debug)
66 return;
67
68 va_start(ap, fmt);
69
70 (void) fprintf(stderr, "dtrace DOF: ");
71
72 (void) vfprintf(stderr, fmt, ap);
73
74 if (fmt[strlen(fmt) - 1] != '\n')
75 (void) fprintf(stderr, ": %s\n", strerror(errno));
76
77 va_end(ap);
78 }
79
80 /*
81 * Users may set the following environment variable to affect the way
82 * helper initialization takes place:
83 *
84 * DTRACE_DOF_INIT_DEBUG enable debugging output
85 * DTRACE_DOF_INIT_DISABLE disable helper loading
86 * DTRACE_DOF_INIT_DEVNAME set the path to the helper node
87 */
88 void
dtrace_link_init(void)89 dtrace_link_init(void)
90 {
91 if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL)
92 dof_init_debug = B_TRUE;
93 }
94
95 void
dtrace_link_dof(dof_hdr_t * dof,Lmid_t lmid,const char * name,uintptr_t addr)96 dtrace_link_dof(dof_hdr_t *dof, Lmid_t lmid, const char *name, uintptr_t addr)
97 {
98 const char *modname;
99 const char *p;
100 #ifdef _LP64
101 Elf64_Ehdr *elf;
102 #else
103 Elf32_Ehdr *elf;
104 #endif
105 dof_helper_t dh;
106 int fd;
107
108 if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL)
109 return;
110
111 if ((modname = strrchr(name, '/')) == NULL)
112 modname = name;
113 else
114 modname++;
115
116 if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 ||
117 dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 ||
118 dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 ||
119 dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) {
120 dprintf(0, ".SUNW_dof section corrupt for %s\n", modname);
121 return;
122 }
123
124 elf = (void *)addr;
125
126 dh.dofhp_dof = (uintptr_t)dof;
127 dh.dofhp_addr = elf->e_type == ET_DYN ? addr : 0;
128
129 if (lmid == LM_ID_BASE) {
130 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
131 "%s", modname);
132 } else {
133 (void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
134 "LM%lu`%s", lmid, modname);
135 }
136
137 if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL)
138 devname = p;
139
140 if ((fd = open64(devname, O_RDWR)) < 0) {
141 dprintf(1, "failed to open helper device %s", devname);
142
143 /*
144 * If the device path wasn't explicitly set, try again with
145 * the old device path.
146 */
147 if (p != NULL)
148 return;
149
150 devname = olddevname;
151
152 if ((fd = open64(devname, O_RDWR)) < 0) {
153 dprintf(1, "failed to open helper device %s", devname);
154 return;
155 }
156 }
157
158 if (ioctl(fd, DTRACEHIOC_ADDDOF, &dh) == -1) {
159 dprintf(1, "DTrace ioctl failed for DOF at %p in %s", dof,
160 name);
161 } else {
162 dprintf(1, "DTrace ioctl succeeded for DOF at %p in %s\n", dof,
163 name);
164 }
165 (void) close(fd);
166 }
167