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/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California.
* Copyright (c) 2005 Robert N. M. Watson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/kern/kern_ktrace.c 237719 2012-06-28 18:38:24Z jhb $");
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/ktrace.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/syslog.h>
#include <sys/sysproto.h>
#include <security/mac/mac_framework.h>
/*
* The ktrace facility allows the tracing of certain key events in user space
* processes, such as system calls, signal delivery, context switches, and
* user generated events using utrace(2). It works by streaming event
* records and data to a vnode associated with the process using the
* ktrace(2) system call. In general, records can be written directly from
* the context that generates the event. One important exception to this is
* during a context switch, where sleeping is not permitted. To handle this
* case, trace events are generated using in-kernel ktr_request records, and
* then delivered to disk at a convenient moment -- either immediately, the
* next traceable event, at system call return, or at process exit.
*
* When dealing with multiple threads or processes writing to the same event
* log, ordering guarantees are weak: specifically, if an event has multiple
* records (i.e., system call enter and return), they may be interlaced with
* records from another event. Process and thread ID information is provided
* in the record, and user applications can de-interlace events if required.
*/
static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
#ifdef KTRACE
FEATURE(ktrace, "Kernel support for system-call tracing");
#ifndef KTRACE_REQUEST_POOL
#define KTRACE_REQUEST_POOL 100
#endif
struct ktr_request {
struct ktr_header ktr_header;
void *ktr_buffer;
union {
struct ktr_proc_ctor ktr_proc_ctor;
struct ktr_syscall ktr_syscall;
struct ktr_sysret ktr_sysret;
struct ktr_genio ktr_genio;
struct ktr_psig ktr_psig;
struct ktr_csw ktr_csw;
struct ktr_fault ktr_fault;
struct ktr_faultend ktr_faultend;
} ktr_data;
STAILQ_ENTRY(ktr_request) ktr_list;
};
static int data_lengths[] = {
0, /* none */
offsetof(struct ktr_syscall, ktr_args), /* KTR_SYSCALL */
sizeof(struct ktr_sysret), /* KTR_SYSRET */
0, /* KTR_NAMEI */
sizeof(struct ktr_genio), /* KTR_GENIO */
sizeof(struct ktr_psig), /* KTR_PSIG */
sizeof(struct ktr_csw), /* KTR_CSW */
0, /* KTR_USER */
0, /* KTR_STRUCT */
0, /* KTR_SYSCTL */
sizeof(struct ktr_proc_ctor), /* KTR_PROCCTOR */
0, /* KTR_PROCDTOR */
sizeof(struct ktr_fault), /* KTR_FAULT */
sizeof(struct ktr_faultend), /* KTR_FAULTEND */
};
static STAILQ_HEAD(, ktr_request) ktr_free;
static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD, 0, "KTRACE options");
static u_int ktr_requestpool = KTRACE_REQUEST_POOL;
TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool);
static u_int ktr_geniosize = PAGE_SIZE;
TUNABLE_INT("kern.ktrace.genio_size", &ktr_geniosize);
SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RW, &ktr_geniosize,
0, "Maximum size of genio event payload");
static int print_message = 1;
static struct mtx ktrace_mtx;
static struct sx ktrace_sx;
static void ktrace_init(void *dummy);
static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS);
static u_int ktrace_resize_pool(u_int oldsize, u_int newsize);
static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type);
static struct ktr_request *ktr_getrequest(int type);
static void ktr_submitrequest(struct thread *td, struct ktr_request *req);
static void ktr_freeproc(struct proc *p, struct ucred **uc,
struct vnode **vp);
static void ktr_freerequest(struct ktr_request *req);
static void ktr_freerequest_locked(struct ktr_request *req);
static void ktr_writerequest(struct thread *td, struct ktr_request *req);
static int ktrcanset(struct thread *,struct proc *);
static int ktrsetchildren(struct thread *,struct proc *,int,int,struct vnode *);
static int ktrops(struct thread *,struct proc *,int,int,struct vnode *);
static void ktrprocctor_entered(struct thread *, struct proc *);
/*
* ktrace itself generates events, such as context switches, which we do not
* wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine
* whether or not it is in a region where tracing of events should be
* suppressed.
*/
static void
ktrace_enter(struct thread *td)
{
KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set"));
td->td_pflags |= TDP_INKTRACE;
}
static void
ktrace_exit(struct thread *td)
{
KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set"));
td->td_pflags &= ~TDP_INKTRACE;
}
static void
ktrace_assert(struct thread *td)
{
KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set"));
}
static void
ktrace_init(void *dummy)
{
struct ktr_request *req;
int i;
mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET);
sx_init(&ktrace_sx, "ktrace_sx");
STAILQ_INIT(&ktr_free);
for (i = 0; i < ktr_requestpool; i++) {
req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK);
STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
}
}
SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL);
static int
sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS)
{
struct thread *td;
u_int newsize, oldsize, wantsize;
int error;
/* Handle easy read-only case first to avoid warnings from GCC. */
if (!req->newptr) {
oldsize = ktr_requestpool;
return (SYSCTL_OUT(req, &oldsize, sizeof(u_int)));
}
error = SYSCTL_IN(req, &wantsize, sizeof(u_int));
if (error)
return (error);
td = curthread;
ktrace_enter(td);
oldsize = ktr_requestpool;
newsize = ktrace_resize_pool(oldsize, wantsize);
ktrace_exit(td);
error = SYSCTL_OUT(req, &oldsize, sizeof(u_int));
if (error)
return (error);
if (wantsize > oldsize && newsize < wantsize)
return (ENOSPC);
return (0);
}
SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool, CTLTYPE_UINT|CTLFLAG_RW,
&ktr_requestpool, 0, sysctl_kern_ktrace_request_pool, "IU",
"Pool buffer size for ktrace(1)");
static u_int
ktrace_resize_pool(u_int oldsize, u_int newsize)
{
STAILQ_HEAD(, ktr_request) ktr_new;
struct ktr_request *req;
int bound;
print_message = 1;
bound = newsize - oldsize;
if (bound == 0)
return (ktr_requestpool);
if (bound < 0) {
mtx_lock(&ktrace_mtx);
/* Shrink pool down to newsize if possible. */
while (bound++ < 0) {
req = STAILQ_FIRST(&ktr_free);
if (req == NULL)
break;
STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
ktr_requestpool--;
free(req, M_KTRACE);
}
} else {
/* Grow pool up to newsize. */
STAILQ_INIT(&ktr_new);
while (bound-- > 0) {
req = malloc(sizeof(struct ktr_request), M_KTRACE,
M_WAITOK);
STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list);
}
mtx_lock(&ktrace_mtx);
STAILQ_CONCAT(&ktr_free, &ktr_new);
ktr_requestpool += (newsize - oldsize);
}
mtx_unlock(&ktrace_mtx);
return (ktr_requestpool);
}
/* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */
CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) ==
(sizeof((struct thread *)NULL)->td_name));
static struct ktr_request *
ktr_getrequest_entered(struct thread *td, int type)
{
struct ktr_request *req;
struct proc *p = td->td_proc;
int pm;
mtx_lock(&ktrace_mtx);
if (!KTRCHECK(td, type)) {
mtx_unlock(&ktrace_mtx);
return (NULL);
}
req = STAILQ_FIRST(&ktr_free);
if (req != NULL) {
STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
req->ktr_header.ktr_type = type;
if (p->p_traceflag & KTRFAC_DROP) {
req->ktr_header.ktr_type |= KTR_DROP;
p->p_traceflag &= ~KTRFAC_DROP;
}
mtx_unlock(&ktrace_mtx);
microtime(&req->ktr_header.ktr_time);
req->ktr_header.ktr_pid = p->p_pid;
req->ktr_header.ktr_tid = td->td_tid;
bcopy(td->td_name, req->ktr_header.ktr_comm,
sizeof(req->ktr_header.ktr_comm));
req->ktr_buffer = NULL;
req->ktr_header.ktr_len = 0;
} else {
p->p_traceflag |= KTRFAC_DROP;
pm = print_message;
print_message = 0;
mtx_unlock(&ktrace_mtx);
if (pm)
printf("Out of ktrace request objects.\n");
}
return (req);
}
static struct ktr_request *
ktr_getrequest(int type)
{
struct thread *td = curthread;
struct ktr_request *req;
ktrace_enter(td);
req = ktr_getrequest_entered(td, type);
if (req == NULL)
ktrace_exit(td);
return (req);
}
/*
* Some trace generation environments don't permit direct access to VFS,
* such as during a context switch where sleeping is not allowed. Under these
* circumstances, queue a request to the thread to be written asynchronously
* later.
*/
static void
ktr_enqueuerequest(struct thread *td, struct ktr_request *req)
{
mtx_lock(&ktrace_mtx);
STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
mtx_unlock(&ktrace_mtx);
}
/*
* Drain any pending ktrace records from the per-thread queue to disk. This
* is used both internally before committing other records, and also on
* system call return. We drain all the ones we can find at the time when
* drain is requested, but don't keep draining after that as those events
* may be approximately "after" the current event.
*/
static void
ktr_drain(struct thread *td)
{
struct ktr_request *queued_req;
STAILQ_HEAD(, ktr_request) local_queue;
ktrace_assert(td);
sx_assert(&ktrace_sx, SX_XLOCKED);
STAILQ_INIT(&local_queue);
if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) {
mtx_lock(&ktrace_mtx);
STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr);
mtx_unlock(&ktrace_mtx);
while ((queued_req = STAILQ_FIRST(&local_queue))) {
STAILQ_REMOVE_HEAD(&local_queue, ktr_list);
ktr_writerequest(td, queued_req);
ktr_freerequest(queued_req);
}
}
}
/*
* Submit a trace record for immediate commit to disk -- to be used only
* where entering VFS is OK. First drain any pending records that may have
* been cached in the thread.
*/
static void
ktr_submitrequest(struct thread *td, struct ktr_request *req)
{
ktrace_assert(td);
sx_xlock(&ktrace_sx);
ktr_drain(td);
ktr_writerequest(td, req);
ktr_freerequest(req);
sx_xunlock(&ktrace_sx);
ktrace_exit(td);
}
static void
ktr_freerequest(struct ktr_request *req)
{
mtx_lock(&ktrace_mtx);
ktr_freerequest_locked(req);
mtx_unlock(&ktrace_mtx);
}
static void
ktr_freerequest_locked(struct ktr_request *req)
{
mtx_assert(&ktrace_mtx, MA_OWNED);
if (req->ktr_buffer != NULL)
free(req->ktr_buffer, M_KTRACE);
STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
}
/*
* Disable tracing for a process and release all associated resources.
* The caller is responsible for releasing a reference on the returned
* vnode and credentials.
*/
static void
ktr_freeproc(struct proc *p, struct ucred **uc, struct vnode **vp)
{
struct ktr_request *req;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&ktrace_mtx, MA_OWNED);
*uc = p->p_tracecred;
p->p_tracecred = NULL;
if (vp != NULL)
*vp = p->p_tracevp;
p->p_tracevp = NULL;
p->p_traceflag = 0;
while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) {
STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list);
ktr_freerequest_locked(req);
}
}
void
ktrsyscall(code, narg, args)
int code, narg;
register_t args[];
{
struct ktr_request *req;
struct ktr_syscall *ktp;
size_t buflen;
char *buf = NULL;
buflen = sizeof(register_t) * narg;
if (buflen > 0) {
buf = malloc(buflen, M_KTRACE, M_WAITOK);
bcopy(args, buf, buflen);
}
req = ktr_getrequest(KTR_SYSCALL);
if (req == NULL) {
if (buf != NULL)
free(buf, M_KTRACE);
return;
}
ktp = &req->ktr_data.ktr_syscall;
ktp->ktr_code = code;
ktp->ktr_narg = narg;
if (buflen > 0) {
req->ktr_header.ktr_len = buflen;
req->ktr_buffer = buf;
}
ktr_submitrequest(curthread, req);
}
void
ktrsysret(code, error, retval)
int code, error;
register_t retval;
{
struct ktr_request *req;
struct ktr_sysret *ktp;
req = ktr_getrequest(KTR_SYSRET);
if (req == NULL)
return;
ktp = &req->ktr_data.ktr_sysret;
ktp->ktr_code = code;
ktp->ktr_error = error;
ktp->ktr_retval = ((error == 0) ? retval: 0); /* what about val2 ? */
ktr_submitrequest(curthread, req);
}
/*
* When a setuid process execs, disable tracing.
*
* XXX: We toss any pending asynchronous records.
*/
void
ktrprocexec(struct proc *p, struct ucred **uc, struct vnode **vp)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_lock(&ktrace_mtx);
ktr_freeproc(p, uc, vp);
mtx_unlock(&ktrace_mtx);
}
/*
* When a process exits, drain per-process asynchronous trace records
* and disable tracing.
*/
void
ktrprocexit(struct thread *td)
{
struct ktr_request *req;
struct proc *p;
struct ucred *cred;
struct vnode *vp;
int vfslocked;
p = td->td_proc;
if (p->p_traceflag == 0)
return;
ktrace_enter(td);
req = ktr_getrequest_entered(td, KTR_PROCDTOR);
if (req != NULL)
ktr_enqueuerequest(td, req);
sx_xlock(&ktrace_sx);
ktr_drain(td);
sx_xunlock(&ktrace_sx);
PROC_LOCK(p);
mtx_lock(&ktrace_mtx);
ktr_freeproc(p, &cred, &vp);
mtx_unlock(&ktrace_mtx);
PROC_UNLOCK(p);
if (vp != NULL) {
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
if (cred != NULL)
crfree(cred);
ktrace_exit(td);
}
static void
ktrprocctor_entered(struct thread *td, struct proc *p)
{
struct ktr_proc_ctor *ktp;
struct ktr_request *req;
struct thread *td2;
ktrace_assert(td);
td2 = FIRST_THREAD_IN_PROC(p);
req = ktr_getrequest_entered(td2, KTR_PROCCTOR);
if (req == NULL)
return;
ktp = &req->ktr_data.ktr_proc_ctor;
ktp->sv_flags = p->p_sysent->sv_flags;
ktr_enqueuerequest(td2, req);
}
void
ktrprocctor(struct proc *p)
{
struct thread *td = curthread;
if ((p->p_traceflag & KTRFAC_MASK) == 0)
return;
ktrace_enter(td);
ktrprocctor_entered(td, p);
ktrace_exit(td);
}
/*
* When a process forks, enable tracing in the new process if needed.
*/
void
ktrprocfork(struct proc *p1, struct proc *p2)
{
PROC_LOCK(p1);
mtx_lock(&ktrace_mtx);
KASSERT(p2->p_tracevp == NULL, ("new process has a ktrace vnode"));
if (p1->p_traceflag & KTRFAC_INHERIT) {
p2->p_traceflag = p1->p_traceflag;
if ((p2->p_tracevp = p1->p_tracevp) != NULL) {
VREF(p2->p_tracevp);
KASSERT(p1->p_tracecred != NULL,
("ktrace vnode with no cred"));
p2->p_tracecred = crhold(p1->p_tracecred);
}
}
mtx_unlock(&ktrace_mtx);
PROC_UNLOCK(p1);
ktrprocctor(p2);
}
/*
* When a thread returns, drain any asynchronous records generated by the
* system call.
*/
void
ktruserret(struct thread *td)
{
ktrace_enter(td);
sx_xlock(&ktrace_sx);
ktr_drain(td);
sx_xunlock(&ktrace_sx);
ktrace_exit(td);
}
void
ktrnamei(path)
char *path;
{
struct ktr_request *req;
int namelen;
char *buf = NULL;
namelen = strlen(path);
if (namelen > 0) {
buf = malloc(namelen, M_KTRACE, M_WAITOK);
bcopy(path, buf, namelen);
}
req = ktr_getrequest(KTR_NAMEI);
if (req == NULL) {
if (buf != NULL)
free(buf, M_KTRACE);
return;
}
if (namelen > 0) {
req->ktr_header.ktr_len = namelen;
req->ktr_buffer = buf;
}
ktr_submitrequest(curthread, req);
}
void
ktrsysctl(name, namelen)
int *name;
u_int namelen;
{
struct ktr_request *req;
u_int mib[CTL_MAXNAME + 2];
char *mibname;
size_t mibnamelen;
int error;
/* Lookup name of mib. */
KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long"));
mib[0] = 0;
mib[1] = 1;
bcopy(name, mib + 2, namelen * sizeof(*name));
mibnamelen = 128;
mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK);
error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen,
NULL, 0, &mibnamelen, 0);
if (error) {
free(mibname, M_KTRACE);
return;
}
req = ktr_getrequest(KTR_SYSCTL);
if (req == NULL) {
free(mibname, M_KTRACE);
return;
}
req->ktr_header.ktr_len = mibnamelen;
req->ktr_buffer = mibname;
ktr_submitrequest(curthread, req);
}
void
ktrgenio(fd, rw, uio, error)
int fd;
enum uio_rw rw;
struct uio *uio;
int error;
{
struct ktr_request *req;
struct ktr_genio *ktg;
int datalen;
char *buf;
if (error) {
free(uio, M_IOV);
return;
}
uio->uio_offset = 0;
uio->uio_rw = UIO_WRITE;
datalen = MIN(uio->uio_resid, ktr_geniosize);
buf = malloc(datalen, M_KTRACE, M_WAITOK);
error = uiomove(buf, datalen, uio);
free(uio, M_IOV);
if (error) {
free(buf, M_KTRACE);
return;
}
req = ktr_getrequest(KTR_GENIO);
if (req == NULL) {
free(buf, M_KTRACE);
return;
}
ktg = &req->ktr_data.ktr_genio;
ktg->ktr_fd = fd;
ktg->ktr_rw = rw;
req->ktr_header.ktr_len = datalen;
req->ktr_buffer = buf;
ktr_submitrequest(curthread, req);
}
void
ktrpsig(sig, action, mask, code)
int sig;
sig_t action;
sigset_t *mask;
int code;
{
struct thread *td = curthread;
struct ktr_request *req;
struct ktr_psig *kp;
req = ktr_getrequest(KTR_PSIG);
if (req == NULL)
return;
kp = &req->ktr_data.ktr_psig;
kp->signo = (char)sig;
kp->action = action;
kp->mask = *mask;
kp->code = code;
ktr_enqueuerequest(td, req);
ktrace_exit(td);
}
void
ktrcsw(out, user, wmesg)
int out, user;
const char *wmesg;
{
struct thread *td = curthread;
struct ktr_request *req;
struct ktr_csw *kc;
req = ktr_getrequest(KTR_CSW);
if (req == NULL)
return;
kc = &req->ktr_data.ktr_csw;
kc->out = out;
kc->user = user;
if (wmesg != NULL)
strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg));
else
bzero(kc->wmesg, sizeof(kc->wmesg));
ktr_enqueuerequest(td, req);
ktrace_exit(td);
}
void
ktrstruct(name, data, datalen)
const char *name;
void *data;
size_t datalen;
{
struct ktr_request *req;
char *buf = NULL;
size_t buflen;
if (!data)
datalen = 0;
buflen = strlen(name) + 1 + datalen;
buf = malloc(buflen, M_KTRACE, M_WAITOK);
strcpy(buf, name);
bcopy(data, buf + strlen(name) + 1, datalen);
if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) {
free(buf, M_KTRACE);
return;
}
req->ktr_buffer = buf;
req->ktr_header.ktr_len = buflen;
ktr_submitrequest(curthread, req);
}
void
ktrfault(vaddr, type)
vm_offset_t vaddr;
int type;
{
struct thread *td = curthread;
struct ktr_request *req;
struct ktr_fault *kf;
req = ktr_getrequest(KTR_FAULT);
if (req == NULL)
return;
kf = &req->ktr_data.ktr_fault;
kf->vaddr = vaddr;
kf->type = type;
ktr_enqueuerequest(td, req);
ktrace_exit(td);
}
void
ktrfaultend(result)
int result;
{
struct thread *td = curthread;
struct ktr_request *req;
struct ktr_faultend *kf;
req = ktr_getrequest(KTR_FAULTEND);
if (req == NULL)
return;
kf = &req->ktr_data.ktr_faultend;
kf->result = result;
ktr_enqueuerequest(td, req);
ktrace_exit(td);
}
#endif /* KTRACE */
/* Interface and common routines */
#ifndef _SYS_SYSPROTO_H_
struct ktrace_args {
char *fname;
int ops;
int facs;
int pid;
};
#endif
/* ARGSUSED */
int
sys_ktrace(td, uap)
struct thread *td;
register struct ktrace_args *uap;
{
#ifdef KTRACE
register struct vnode *vp = NULL;
register struct proc *p;
struct pgrp *pg;
int facs = uap->facs & ~KTRFAC_ROOT;
int ops = KTROP(uap->ops);
int descend = uap->ops & KTRFLAG_DESCEND;
int nfound, ret = 0;
int flags, error = 0, vfslocked;
struct nameidata nd;
struct ucred *cred;
/*
* Need something to (un)trace.
*/
if (ops != KTROP_CLEARFILE && facs == 0)
return (EINVAL);
ktrace_enter(td);
if (ops != KTROP_CLEAR) {
/*
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_USERSPACE,
uap->fname, td);
flags = FREAD | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, 0, NULL);
if (error) {
ktrace_exit(td);
return (error);
}
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
VOP_UNLOCK(vp, 0);
if (vp->v_type != VREG) {
(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
VFS_UNLOCK_GIANT(vfslocked);
ktrace_exit(td);
return (EACCES);
}
VFS_UNLOCK_GIANT(vfslocked);
}
/*
* Clear all uses of the tracefile.
*/
if (ops == KTROP_CLEARFILE) {
int vrele_count;
vrele_count = 0;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_tracevp == vp) {
if (ktrcanset(td, p)) {
mtx_lock(&ktrace_mtx);
ktr_freeproc(p, &cred, NULL);
mtx_unlock(&ktrace_mtx);
vrele_count++;
crfree(cred);
} else
error = EPERM;
}
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
if (vrele_count > 0) {
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
while (vrele_count-- > 0)
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
goto done;
}
/*
* do it
*/
sx_slock(&proctree_lock);
if (uap->pid < 0) {
/*
* by process group
*/
pg = pgfind(-uap->pid);
if (pg == NULL) {
sx_sunlock(&proctree_lock);
error = ESRCH;
goto done;
}
/*
* ktrops() may call vrele(). Lock pg_members
* by the proctree_lock rather than pg_mtx.
*/
PGRP_UNLOCK(pg);
nfound = 0;
LIST_FOREACH(p, &pg->pg_members, p_pglist) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW ||
p_cansee(td, p) != 0) {
PROC_UNLOCK(p);
continue;
}
nfound++;
if (descend)
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(td, p, ops, facs, vp);
}
if (nfound == 0) {
sx_sunlock(&proctree_lock);
error = ESRCH;
goto done;
}
} else {
/*
* by pid
*/
p = pfind(uap->pid);
if (p == NULL)
error = ESRCH;
else
error = p_cansee(td, p);
if (error) {
if (p != NULL)
PROC_UNLOCK(p);
sx_sunlock(&proctree_lock);
goto done;
}
if (descend)
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(td, p, ops, facs, vp);
}
sx_sunlock(&proctree_lock);
if (!ret)
error = EPERM;
done:
if (vp != NULL) {
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
(void) vn_close(vp, FWRITE, td->td_ucred, td);
VFS_UNLOCK_GIANT(vfslocked);
}
ktrace_exit(td);
return (error);
#else /* !KTRACE */
return (ENOSYS);
#endif /* KTRACE */
}
/* ARGSUSED */
int
sys_utrace(td, uap)
struct thread *td;
register struct utrace_args *uap;
{
#ifdef KTRACE
struct ktr_request *req;
void *cp;
int error;
if (!KTRPOINT(td, KTR_USER))
return (0);
if (uap->len > KTR_USER_MAXLEN)
return (EINVAL);
cp = malloc(uap->len, M_KTRACE, M_WAITOK);
error = copyin(uap->addr, cp, uap->len);
if (error) {
free(cp, M_KTRACE);
return (error);
}
req = ktr_getrequest(KTR_USER);
if (req == NULL) {
free(cp, M_KTRACE);
return (ENOMEM);
}
req->ktr_buffer = cp;
req->ktr_header.ktr_len = uap->len;
ktr_submitrequest(td, req);
return (0);
#else /* !KTRACE */
return (ENOSYS);
#endif /* KTRACE */
}
#ifdef KTRACE
static int
ktrops(td, p, ops, facs, vp)
struct thread *td;
struct proc *p;
int ops, facs;
struct vnode *vp;
{
struct vnode *tracevp = NULL;
struct ucred *tracecred = NULL;
PROC_LOCK_ASSERT(p, MA_OWNED);
if (!ktrcanset(td, p)) {
PROC_UNLOCK(p);
return (0);
}
if (p->p_flag & P_WEXIT) {
/* If the process is exiting, just ignore it. */
PROC_UNLOCK(p);
return (1);
}
mtx_lock(&ktrace_mtx);
if (ops == KTROP_SET) {
if (p->p_tracevp != vp) {
/*
* if trace file already in use, relinquish below
*/
tracevp = p->p_tracevp;
VREF(vp);
p->p_tracevp = vp;
}
if (p->p_tracecred != td->td_ucred) {
tracecred = p->p_tracecred;
p->p_tracecred = crhold(td->td_ucred);
}
p->p_traceflag |= facs;
if (priv_check(td, PRIV_KTRACE) == 0)
p->p_traceflag |= KTRFAC_ROOT;
} else {
/* KTROP_CLEAR */
if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0)
/* no more tracing */
ktr_freeproc(p, &tracecred, &tracevp);
}
mtx_unlock(&ktrace_mtx);
if ((p->p_traceflag & KTRFAC_MASK) != 0)
ktrprocctor_entered(td, p);
PROC_UNLOCK(p);
if (tracevp != NULL) {
int vfslocked;
vfslocked = VFS_LOCK_GIANT(tracevp->v_mount);
vrele(tracevp);
VFS_UNLOCK_GIANT(vfslocked);
}
if (tracecred != NULL)
crfree(tracecred);
return (1);
}
static int
ktrsetchildren(td, top, ops, facs, vp)
struct thread *td;
struct proc *top;
int ops, facs;
struct vnode *vp;
{
register struct proc *p;
register int ret = 0;
p = top;
PROC_LOCK_ASSERT(p, MA_OWNED);
sx_assert(&proctree_lock, SX_LOCKED);
for (;;) {
ret |= ktrops(td, p, ops, facs, vp);
/*
* If this process has children, descend to them next,
* otherwise do any siblings, and if done with this level,
* follow back up the tree (but not past top).
*/
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top)
return (ret);
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
PROC_LOCK(p);
}
/*NOTREACHED*/
}
static void
ktr_writerequest(struct thread *td, struct ktr_request *req)
{
struct ktr_header *kth;
struct vnode *vp;
struct proc *p;
struct ucred *cred;
struct uio auio;
struct iovec aiov[3];
struct mount *mp;
int datalen, buflen, vrele_count;
int error, vfslocked;
/*
* We hold the vnode and credential for use in I/O in case ktrace is
* disabled on the process as we write out the request.
*
* XXXRW: This is not ideal: we could end up performing a write after
* the vnode has been closed.
*/
mtx_lock(&ktrace_mtx);
vp = td->td_proc->p_tracevp;
cred = td->td_proc->p_tracecred;
/*
* If vp is NULL, the vp has been cleared out from under this
* request, so just drop it. Make sure the credential and vnode are
* in sync: we should have both or neither.
*/
if (vp == NULL) {
KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL"));
mtx_unlock(&ktrace_mtx);
return;
}
VREF(vp);
KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL"));
crhold(cred);
mtx_unlock(&ktrace_mtx);
kth = &req->ktr_header;
KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) <
sizeof(data_lengths) / sizeof(data_lengths[0]),
("data_lengths array overflow"));
datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP];
buflen = kth->ktr_len;
auio.uio_iov = &aiov[0];
auio.uio_offset = 0;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_WRITE;
aiov[0].iov_base = (caddr_t)kth;
aiov[0].iov_len = sizeof(struct ktr_header);
auio.uio_resid = sizeof(struct ktr_header);
auio.uio_iovcnt = 1;
auio.uio_td = td;
if (datalen != 0) {
aiov[1].iov_base = (caddr_t)&req->ktr_data;
aiov[1].iov_len = datalen;
auio.uio_resid += datalen;
auio.uio_iovcnt++;
kth->ktr_len += datalen;
}
if (buflen != 0) {
KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write"));
aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer;
aiov[auio.uio_iovcnt].iov_len = buflen;
auio.uio_resid += buflen;
auio.uio_iovcnt++;
}
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
#ifdef MAC
error = mac_vnode_check_write(cred, NOCRED, vp);
if (error == 0)
#endif
error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred);
VOP_UNLOCK(vp, 0);
vn_finished_write(mp);
crfree(cred);
if (!error) {
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
return;
}
VFS_UNLOCK_GIANT(vfslocked);
/*
* If error encountered, give up tracing on this vnode. We defer
* all the vrele()'s on the vnode until after we are finished walking
* the various lists to avoid needlessly holding locks.
* NB: at this point we still hold the vnode reference that must
* not go away as we need the valid vnode to compare with. Thus let
* vrele_count start at 1 and the reference will be freed
* by the loop at the end after our last use of vp.
*/
log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
error);
vrele_count = 1;
/*
* First, clear this vnode from being used by any processes in the
* system.
* XXX - If one process gets an EPERM writing to the vnode, should
* we really do this? Other processes might have suitable
* credentials for the operation.
*/
cred = NULL;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_tracevp == vp) {
mtx_lock(&ktrace_mtx);
ktr_freeproc(p, &cred, NULL);
mtx_unlock(&ktrace_mtx);
vrele_count++;
}
PROC_UNLOCK(p);
if (cred != NULL) {
crfree(cred);
cred = NULL;
}
}
sx_sunlock(&allproc_lock);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
while (vrele_count-- > 0)
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
/*
* Return true if caller has permission to set the ktracing state
* of target. Essentially, the target can't possess any
* more permissions than the caller. KTRFAC_ROOT signifies that
* root previously set the tracing status on the target process, and
* so, only root may further change it.
*/
static int
ktrcanset(td, targetp)
struct thread *td;
struct proc *targetp;
{
PROC_LOCK_ASSERT(targetp, MA_OWNED);
if (targetp->p_traceflag & KTRFAC_ROOT &&
priv_check(td, PRIV_KTRACE))
return (0);
if (p_candebug(td, targetp) != 0)
return (0);
return (1);
}
#endif /* KTRACE */