xref: /onnv-gate/usr/src/lib/libdtrace/common/drti.c (revision 8337:079ecc003ca6)
10Sstevel@tonic-gate /*
20Sstevel@tonic-gate  * CDDL HEADER START
30Sstevel@tonic-gate  *
40Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*8337SJonathan.Haslam@Sun.COM  * Common Development and Distribution License (the "License").
6*8337SJonathan.Haslam@Sun.COM  * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate  *
80Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate  * See the License for the specific language governing permissions
110Sstevel@tonic-gate  * and limitations under the License.
120Sstevel@tonic-gate  *
130Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate  *
190Sstevel@tonic-gate  * CDDL HEADER END
200Sstevel@tonic-gate  */
210Sstevel@tonic-gate /*
22*8337SJonathan.Haslam@Sun.COM  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
230Sstevel@tonic-gate  * Use is subject to license terms.
240Sstevel@tonic-gate  */
250Sstevel@tonic-gate 
260Sstevel@tonic-gate #include <unistd.h>
270Sstevel@tonic-gate #include <fcntl.h>
280Sstevel@tonic-gate #include <dlfcn.h>
290Sstevel@tonic-gate #include <link.h>
300Sstevel@tonic-gate #include <sys/dtrace.h>
310Sstevel@tonic-gate 
320Sstevel@tonic-gate #include <stdarg.h>
330Sstevel@tonic-gate #include <stdio.h>
340Sstevel@tonic-gate #include <stdlib.h>
350Sstevel@tonic-gate #include <string.h>
360Sstevel@tonic-gate #include <errno.h>
370Sstevel@tonic-gate 
380Sstevel@tonic-gate /*
390Sstevel@tonic-gate  * In Solaris 10 GA, the only mechanism for communicating helper information
400Sstevel@tonic-gate  * is through the DTrace helper pseudo-device node in /devices; there is
410Sstevel@tonic-gate  * no /dev link. Because of this, USDT providers and helper actions don't
420Sstevel@tonic-gate  * work inside of non-global zones. This issue was addressed by adding
430Sstevel@tonic-gate  * the /dev and having this initialization code use that /dev link. If the
440Sstevel@tonic-gate  * /dev link doesn't exist it falls back to looking for the /devices node
450Sstevel@tonic-gate  * as this code may be embedded in a binary which runs on Solaris 10 GA.
460Sstevel@tonic-gate  *
470Sstevel@tonic-gate  * Users may set the following environment variable to affect the way
480Sstevel@tonic-gate  * helper initialization takes place:
490Sstevel@tonic-gate  *
500Sstevel@tonic-gate  *	DTRACE_DOF_INIT_DEBUG		enable debugging output
510Sstevel@tonic-gate  *	DTRACE_DOF_INIT_DISABLE		disable helper loading
520Sstevel@tonic-gate  *	DTRACE_DOF_INIT_DEVNAME		set the path to the helper node
530Sstevel@tonic-gate  */
540Sstevel@tonic-gate 
550Sstevel@tonic-gate static const char *devname = "/dev/dtrace/helper";
560Sstevel@tonic-gate static const char *olddevname = "/devices/pseudo/dtrace@0:helper";
570Sstevel@tonic-gate 
580Sstevel@tonic-gate static const char *modname;	/* Name of this load object */
590Sstevel@tonic-gate static int gen;			/* DOF helper generation */
600Sstevel@tonic-gate extern dof_hdr_t __SUNW_dof;	/* DOF defined in the .SUNW_dof section */
61*8337SJonathan.Haslam@Sun.COM static boolean_t dof_init_debug = B_FALSE;	/* From DTRACE_DOF_INIT_DEBUG */
620Sstevel@tonic-gate 
630Sstevel@tonic-gate static void
dprintf(int debug,const char * fmt,...)640Sstevel@tonic-gate dprintf(int debug, const char *fmt, ...)
650Sstevel@tonic-gate {
660Sstevel@tonic-gate 	va_list ap;
670Sstevel@tonic-gate 
68*8337SJonathan.Haslam@Sun.COM 	if (debug && !dof_init_debug)
690Sstevel@tonic-gate 		return;
700Sstevel@tonic-gate 
710Sstevel@tonic-gate 	va_start(ap, fmt);
720Sstevel@tonic-gate 
730Sstevel@tonic-gate 	if (modname == NULL)
740Sstevel@tonic-gate 		(void) fprintf(stderr, "dtrace DOF: ");
750Sstevel@tonic-gate 	else
760Sstevel@tonic-gate 		(void) fprintf(stderr, "dtrace DOF %s: ", modname);
770Sstevel@tonic-gate 
780Sstevel@tonic-gate 	(void) vfprintf(stderr, fmt, ap);
790Sstevel@tonic-gate 
800Sstevel@tonic-gate 	if (fmt[strlen(fmt) - 1] != '\n')
810Sstevel@tonic-gate 		(void) fprintf(stderr, ": %s\n", strerror(errno));
820Sstevel@tonic-gate 
830Sstevel@tonic-gate 	va_end(ap);
840Sstevel@tonic-gate }
850Sstevel@tonic-gate 
860Sstevel@tonic-gate #pragma init(dtrace_dof_init)
870Sstevel@tonic-gate static void
dtrace_dof_init(void)880Sstevel@tonic-gate dtrace_dof_init(void)
890Sstevel@tonic-gate {
900Sstevel@tonic-gate 	dof_hdr_t *dof = &__SUNW_dof;
910Sstevel@tonic-gate #ifdef _LP64
920Sstevel@tonic-gate 	Elf64_Ehdr *elf;
930Sstevel@tonic-gate #else
940Sstevel@tonic-gate 	Elf32_Ehdr *elf;
950Sstevel@tonic-gate #endif
960Sstevel@tonic-gate 	dof_helper_t dh;
970Sstevel@tonic-gate 	Link_map *lmp;
980Sstevel@tonic-gate 	Lmid_t lmid;
990Sstevel@tonic-gate 	int fd;
1000Sstevel@tonic-gate 	const char *p;
1010Sstevel@tonic-gate 
1020Sstevel@tonic-gate 	if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL)
1030Sstevel@tonic-gate 		return;
1040Sstevel@tonic-gate 
105*8337SJonathan.Haslam@Sun.COM 	if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL)
106*8337SJonathan.Haslam@Sun.COM 		dof_init_debug = B_TRUE;
107*8337SJonathan.Haslam@Sun.COM 
1080Sstevel@tonic-gate 	if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) {
1090Sstevel@tonic-gate 		dprintf(1, "couldn't discover module name or address\n");
1100Sstevel@tonic-gate 		return;
1110Sstevel@tonic-gate 	}
1120Sstevel@tonic-gate 
1130Sstevel@tonic-gate 	if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) {
1140Sstevel@tonic-gate 		dprintf(1, "couldn't discover link map ID\n");
1150Sstevel@tonic-gate 		return;
1160Sstevel@tonic-gate 	}
1170Sstevel@tonic-gate 
1180Sstevel@tonic-gate 	if ((modname = strrchr(lmp->l_name, '/')) == NULL)
1190Sstevel@tonic-gate 		modname = lmp->l_name;
1200Sstevel@tonic-gate 	else
1210Sstevel@tonic-gate 		modname++;
1220Sstevel@tonic-gate 
1230Sstevel@tonic-gate 	if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 ||
1240Sstevel@tonic-gate 	    dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 ||
1250Sstevel@tonic-gate 	    dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 ||
1260Sstevel@tonic-gate 	    dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) {
1270Sstevel@tonic-gate 		dprintf(0, ".SUNW_dof section corrupt\n");
1280Sstevel@tonic-gate 		return;
1290Sstevel@tonic-gate 	}
1300Sstevel@tonic-gate 
1310Sstevel@tonic-gate 	elf = (void *)lmp->l_addr;
1320Sstevel@tonic-gate 
1330Sstevel@tonic-gate 	dh.dofhp_dof = (uintptr_t)dof;
1340Sstevel@tonic-gate 	dh.dofhp_addr = elf->e_type == ET_DYN ? lmp->l_addr : 0;
1350Sstevel@tonic-gate 
1360Sstevel@tonic-gate 	if (lmid == 0) {
1370Sstevel@tonic-gate 		(void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
1380Sstevel@tonic-gate 		    "%s", modname);
1390Sstevel@tonic-gate 	} else {
1400Sstevel@tonic-gate 		(void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
1410Sstevel@tonic-gate 		    "LM%lu`%s", lmid, modname);
1420Sstevel@tonic-gate 	}
1430Sstevel@tonic-gate 
1440Sstevel@tonic-gate 	if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL)
1450Sstevel@tonic-gate 		devname = p;
1460Sstevel@tonic-gate 
1470Sstevel@tonic-gate 	if ((fd = open64(devname, O_RDWR)) < 0) {
1480Sstevel@tonic-gate 		dprintf(1, "failed to open helper device %s", devname);
1490Sstevel@tonic-gate 
1500Sstevel@tonic-gate 		/*
1510Sstevel@tonic-gate 		 * If the device path wasn't explicitly set, try again with
1520Sstevel@tonic-gate 		 * the old device path.
1530Sstevel@tonic-gate 		 */
1540Sstevel@tonic-gate 		if (p != NULL)
1550Sstevel@tonic-gate 			return;
1560Sstevel@tonic-gate 
1570Sstevel@tonic-gate 		devname = olddevname;
1580Sstevel@tonic-gate 
1590Sstevel@tonic-gate 		if ((fd = open64(devname, O_RDWR)) < 0) {
1600Sstevel@tonic-gate 			dprintf(1, "failed to open helper device %s", devname);
1610Sstevel@tonic-gate 			return;
1620Sstevel@tonic-gate 		}
1630Sstevel@tonic-gate 	}
1640Sstevel@tonic-gate 
1650Sstevel@tonic-gate 	if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1)
1660Sstevel@tonic-gate 		dprintf(1, "DTrace ioctl failed for DOF at %p", dof);
1670Sstevel@tonic-gate 	else
1680Sstevel@tonic-gate 		dprintf(1, "DTrace ioctl succeeded for DOF at %p\n", dof);
1690Sstevel@tonic-gate 
1700Sstevel@tonic-gate 	(void) close(fd);
1710Sstevel@tonic-gate }
1720Sstevel@tonic-gate 
1730Sstevel@tonic-gate #pragma fini(dtrace_dof_fini)
1740Sstevel@tonic-gate static void
dtrace_dof_fini(void)1750Sstevel@tonic-gate dtrace_dof_fini(void)
1760Sstevel@tonic-gate {
1770Sstevel@tonic-gate 	int fd;
1780Sstevel@tonic-gate 
1790Sstevel@tonic-gate 	if ((fd = open64(devname, O_RDWR)) < 0) {
1800Sstevel@tonic-gate 		dprintf(1, "failed to open helper device %s", devname);
1810Sstevel@tonic-gate 		return;
1820Sstevel@tonic-gate 	}
1830Sstevel@tonic-gate 
1840Sstevel@tonic-gate 	if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, gen)) == -1)
1850Sstevel@tonic-gate 		dprintf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen);
1860Sstevel@tonic-gate 	else
1870Sstevel@tonic-gate 		dprintf(1, "DTrace ioctl removed DOF (%d)\n", gen);
1880Sstevel@tonic-gate 
1890Sstevel@tonic-gate 	(void) close(fd);
1900Sstevel@tonic-gate }
191