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(1M) -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 */
55const char *devname = "/dev/dtrace/helper";
56static const char *olddevname = "/devices/pseudo/dtrace@0:helper";
57
58static boolean_t dof_init_debug = B_FALSE;
59
60void
61dprintf(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 */
88void
89dtrace_link_init(void)
90{
91	if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL)
92		dof_init_debug = B_TRUE;
93}
94
95void
96dtrace_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