mirror of https://github.com/NetBSD/src.git
240 lines
6.1 KiB
C
240 lines
6.1 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
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* Copyright 2013 Voxer Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/*
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* XXX Hack: Force the use of sys/exec_elf.h, not elfdefinitions.h.
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* Why?
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*
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* - sys/dtrace.h is needed because (XXX why?).
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* => sys/dtrace.h pulls in sys/ctf_api.h
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* => which pulls in sys/elf.h
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* => which pulls in elfdefinitions.h (XXX should it?)
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*
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* - link.h is needed for Link_map.
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* => link.h pulls in link_elf.h
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* => which pulls in sys/exec_elf.h
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*
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* But elfdefinitions.h and sys/exec_elf.h collide over most basic ELF
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* definitions. Since we don't need elfdefinitions.h otherwise, prefer
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* sys/exec_elf.h.
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*/
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#define _SYS_ELFDEFINITIONS_H_
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#include <unistd.h>
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#include <fcntl.h>
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#include <dlfcn.h>
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#include <link.h>
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#include <sys/dtrace.h>
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#include <sys/ioctl.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <libelf.h>
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/*
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* In Solaris 10 GA, the only mechanism for communicating helper information
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* is through the DTrace helper pseudo-device node in /devices; there is
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* no /dev link. Because of this, USDT providers and helper actions don't
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* work inside of non-global zones. This issue was addressed by adding
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* the /dev and having this initialization code use that /dev link. If the
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* /dev link doesn't exist it falls back to looking for the /devices node
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* as this code may be embedded in a binary which runs on Solaris 10 GA.
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*
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* Users may set the following environment variable to affect the way
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* helper initialization takes place:
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*
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* DTRACE_DOF_INIT_DEBUG enable debugging output
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* DTRACE_DOF_INIT_DISABLE disable helper loading
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* DTRACE_DOF_INIT_DEVNAME set the path to the helper node
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*/
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static const char *devnamep = "/dev/dtrace/helper";
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#ifdef illumos
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static const char *olddevname = "/devices/pseudo/dtrace@0:helper";
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#endif
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static const char *modname; /* Name of this load object */
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static int gen; /* DOF helper generation */
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extern dof_hdr_t __SUNW_dof; /* DOF defined in the .SUNW_dof section */
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static boolean_t dof_init_debug = B_FALSE; /* From DTRACE_DOF_INIT_DEBUG */
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static void __printflike(2,3)
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dbg_printf(int debug, const char *fmt, ...)
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{
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va_list ap;
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if (debug && !dof_init_debug)
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return;
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va_start(ap, fmt);
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if (modname == NULL)
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(void) fprintf(stderr, "dtrace DOF: ");
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else
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(void) fprintf(stderr, "dtrace DOF %s: ", modname);
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(void) vfprintf(stderr, fmt, ap);
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if (fmt[strlen(fmt) - 1] != '\n')
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(void) fprintf(stderr, ": %s\n", strerror(errno));
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va_end(ap);
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}
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#ifdef illumos
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#pragma init(dtrace_dof_init)
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#else
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static void dtrace_dof_init(void) __attribute__ ((constructor));
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#endif
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static void
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dtrace_dof_init(void)
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{
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dof_hdr_t *dof = &__SUNW_dof;
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#ifdef _LP64
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Elf64_Ehdr *elf;
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#else
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Elf32_Ehdr *elf;
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#endif
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dof_helper_t dh;
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Link_map *lmp = NULL;
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#ifdef illumos
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Lmid_t lmid;
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#else
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u_long lmid = 0;
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#endif
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int fd;
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const char *p;
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if (getenv("DTRACE_DOF_INIT_DISABLE") != NULL)
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return;
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if (getenv("DTRACE_DOF_INIT_DEBUG") != NULL)
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dof_init_debug = B_TRUE;
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if (dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &lmp) == -1 || lmp == NULL) {
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dbg_printf(1, "couldn't discover module name or address\n");
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return;
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}
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#ifdef illumos
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if (dlinfo(RTLD_SELF, RTLD_DI_LMID, &lmid) == -1) {
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dbg_printf(1, "couldn't discover link map ID\n");
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return;
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}
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#endif
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if ((modname = strrchr(lmp->l_name, '/')) == NULL)
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modname = lmp->l_name;
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else
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modname++;
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if (dof->dofh_ident[DOF_ID_MAG0] != DOF_MAG_MAG0 ||
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dof->dofh_ident[DOF_ID_MAG1] != DOF_MAG_MAG1 ||
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dof->dofh_ident[DOF_ID_MAG2] != DOF_MAG_MAG2 ||
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dof->dofh_ident[DOF_ID_MAG3] != DOF_MAG_MAG3) {
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dbg_printf(0, ".SUNW_dof section corrupt\n");
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return;
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}
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elf = (void *)lmp->l_addr;
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dh.dofhp_dof = (uintptr_t)dof;
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dh.dofhp_addr = elf && elf->e_type == ET_DYN ? (uintptr_t) lmp->l_addr : 0;
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#if defined(__FreeBSD__) || defined(__NetBSD__)
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dh.dofhp_pid = getpid();
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#endif
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if (lmid == 0) {
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(void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
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"%s", modname);
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} else {
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(void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
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"LM%lu`%s", lmid, modname);
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}
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if ((p = getenv("DTRACE_DOF_INIT_DEVNAME")) != NULL)
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devnamep = p;
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if ((fd = open64(devnamep, O_RDWR)) < 0) {
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dbg_printf(1, "failed to open helper device %s", devnamep);
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#ifdef illumos
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/*
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* If the device path wasn't explicitly set, try again with
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* the old device path.
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*/
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if (p != NULL)
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return;
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devnamep = olddevname;
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if ((fd = open64(devnamep, O_RDWR)) < 0) {
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dbg_printf(1, "failed to open helper device %s", devnamep);
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return;
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}
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#else
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return;
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#endif
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}
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if ((gen = ioctl(fd, DTRACEHIOC_ADDDOF, &dh)) == -1)
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dbg_printf(1, "DTrace ioctl failed for DOF at %p", dof);
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else {
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dbg_printf(1, "DTrace ioctl succeeded for DOF at %p\n", dof);
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#if defined(__FreeBSD__) || defined(__NetBSD__)
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gen = dh.dofhp_gen;
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#endif
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}
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(void) close(fd);
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}
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#ifdef illumos
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#pragma fini(dtrace_dof_fini)
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#else
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static void dtrace_dof_fini(void) __attribute__ ((destructor));
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#endif
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static void
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dtrace_dof_fini(void)
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{
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int fd;
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if ((fd = open64(devnamep, O_RDWR)) < 0) {
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dbg_printf(1, "failed to open helper device %s", devnamep);
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return;
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}
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if ((gen = ioctl(fd, DTRACEHIOC_REMOVE, &gen)) == -1)
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dbg_printf(1, "DTrace ioctl failed to remove DOF (%d)\n", gen);
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else
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dbg_printf(1, "DTrace ioctl removed DOF (%d)\n", gen);
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(void) close(fd);
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}
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