NetBSD/sys/kern/kern_ktrace.c

813 lines
18 KiB
C

/* $NetBSD: kern_ktrace.c,v 1.91 2004/06/24 15:06:35 christos Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. 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.
* 3. 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 8.5 (Berkeley) 5/14/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_ktrace.c,v 1.91 2004/06/24 15:06:35 christos Exp $");
#include "opt_ktrace.h"
#include "opt_compat_mach.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/ktrace.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/sa.h>
#include <sys/syscallargs.h>
#ifdef KTRACE
void ktrinitheader(struct ktr_header *, struct proc *, int);
int ktrwrite(struct proc *, struct ktr_header *);
int ktrace_common(struct proc *, int, int, int, struct file *);
int ktrops(struct proc *, struct proc *, int, int, struct file *);
int ktrsetchildren(struct proc *, struct proc *, int, int,
struct file *);
int ktrcanset(struct proc *, struct proc *);
int ktrsamefile(struct file *, struct file *);
/*
* "deep" compare of two files for the purposes of clearing a trace.
* Returns true if they're the same open file, or if they point at the
* same underlying vnode/socket.
*/
int
ktrsamefile(struct file *f1, struct file *f2)
{
return ((f1 == f2) ||
((f1 != NULL) && (f2 != NULL) &&
(f1->f_type == f2->f_type) &&
(f1->f_data == f2->f_data)));
}
void
ktrderef(struct proc *p)
{
struct file *fp = p->p_tracep;
p->p_traceflag = 0;
if (fp == NULL)
return;
p->p_tracep = NULL;
simple_lock(&fp->f_slock);
FILE_USE(fp);
/*
* ktrace file descriptor can't be watched (are not visible to
* userspace), so no kqueue stuff here.
* XXX: The above comment is wrong, because the fktrace file
* descriptor is available in userland.
*/
closef(fp, NULL);
}
void
ktradref(struct proc *p)
{
struct file *fp = p->p_tracep;
fp->f_count++;
}
void
ktrinitheader(struct ktr_header *kth, struct proc *p, int type)
{
(void)memset(kth, 0, sizeof(*kth));
kth->ktr_type = type;
microtime(&kth->ktr_time);
kth->ktr_pid = p->p_pid;
memcpy(kth->ktr_comm, p->p_comm, MAXCOMLEN);
}
int
ktrsyscall(struct proc *p, register_t code, register_t realcode,
const struct sysent *callp, register_t args[])
{
struct ktr_header kth;
struct ktr_syscall *ktp;
register_t *argp;
int argsize, error;
size_t len;
u_int i;
if (callp == NULL)
callp = p->p_emul->e_sysent;
argsize = callp[code].sy_argsize;
#ifdef _LP64
if (p->p_flag & P_32)
argsize = argsize << 1;
#endif
len = sizeof(struct ktr_syscall) + argsize;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSCALL);
ktp = malloc(len, M_TEMP, M_WAITOK);
ktp->ktr_code = realcode;
ktp->ktr_argsize = argsize;
argp = (register_t *)((char *)ktp + sizeof(struct ktr_syscall));
for (i = 0; i < (argsize / sizeof(*argp)); i++)
*argp++ = args[i];
kth.ktr_buf = (caddr_t)ktp;
kth.ktr_len = len;
error = ktrwrite(p, &kth);
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrsysret(struct proc *p, register_t code, int error, register_t *retval)
{
struct ktr_header kth;
struct ktr_sysret ktp;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSRET);
ktp.ktr_code = code;
ktp.ktr_eosys = 0; /* XXX unused */
ktp.ktr_error = error;
ktp.ktr_retval = retval ? retval[0] : 0;
ktp.ktr_retval_1 = retval ? retval[1] : 0;
kth.ktr_buf = (caddr_t)&ktp;
kth.ktr_len = sizeof(struct ktr_sysret);
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrnamei(struct proc *p, char *path)
{
struct ktr_header kth;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_NAMEI);
kth.ktr_len = strlen(path);
kth.ktr_buf = path;
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktremul(struct proc *p)
{
struct ktr_header kth;
const char *emul = p->p_emul->e_name;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_EMUL);
kth.ktr_len = strlen(emul);
kth.ktr_buf = (caddr_t)emul;
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrkmem(struct proc *p, int ktr, const void *buf, size_t len)
{
struct ktr_header kth;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, ktr);
kth.ktr_len = len;
kth.ktr_buf = buf;
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrgenio(struct proc *p, int fd, enum uio_rw rw, struct iovec *iov,
int len, int error)
{
struct ktr_header kth;
struct ktr_genio *ktp;
caddr_t cp;
int resid = len, cnt;
int buflen;
if (error)
return error;
p->p_traceflag |= KTRFAC_ACTIVE;
buflen = min(PAGE_SIZE, len + sizeof(struct ktr_genio));
ktrinitheader(&kth, p, KTR_GENIO);
ktp = malloc(buflen, M_TEMP, M_WAITOK);
ktp->ktr_fd = fd;
ktp->ktr_rw = rw;
kth.ktr_buf = (caddr_t)ktp;
cp = (caddr_t)((char *)ktp + sizeof(struct ktr_genio));
buflen -= sizeof(struct ktr_genio);
while (resid > 0) {
#if 0 /* XXX NJWLWP */
KDASSERT(p->p_cpu != NULL);
KDASSERT(p->p_cpu == curcpu());
#endif
/* XXX NJWLWP */
if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
preempt(1);
cnt = min(iov->iov_len, buflen);
if (cnt > resid)
cnt = resid;
if ((error = copyin(iov->iov_base, cp, cnt)) != 0)
break;
kth.ktr_len = cnt + sizeof(struct ktr_genio);
error = ktrwrite(p, &kth);
if (__predict_false(error != 0))
break;
iov->iov_base = (caddr_t)iov->iov_base + cnt;
iov->iov_len -= cnt;
if (iov->iov_len == 0)
iov++;
resid -= cnt;
}
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrpsig(struct proc *p, int sig, sig_t action, const sigset_t *mask,
const ksiginfo_t *ksi)
{
int error;
struct ktr_header kth;
struct {
struct ktr_psig kp;
siginfo_t si;
} kbuf;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_PSIG);
kbuf.kp.signo = (char)sig;
kbuf.kp.action = action;
kbuf.kp.mask = *mask;
kth.ktr_buf = (caddr_t)&kbuf;
if (ksi) {
kbuf.kp.code = KSI_TRAPCODE(ksi);
(void)memset(&kbuf.si, 0, sizeof(kbuf.si));
kbuf.si._info = ksi->ksi_info;
kth.ktr_len = sizeof(kbuf);
} else {
kbuf.kp.code = 0;
kth.ktr_len = sizeof(struct ktr_psig);
}
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrcsw(struct proc *p, int out, int user)
{
struct ktr_header kth;
struct ktr_csw kc;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_CSW);
kc.out = out;
kc.user = user;
kth.ktr_buf = (caddr_t)&kc;
kth.ktr_len = sizeof(struct ktr_csw);
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktruser(struct proc *p, const char *id, void *addr, size_t len, int ustr)
{
struct ktr_header kth;
struct ktr_user *ktp;
caddr_t user_dta;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_USER);
ktp = malloc(sizeof(struct ktr_user) + len, M_TEMP, M_WAITOK);
if (ustr) {
if (copyinstr(id, ktp->ktr_id, KTR_USER_MAXIDLEN, NULL) != 0)
ktp->ktr_id[0] = '\0';
} else
strncpy(ktp->ktr_id, id, KTR_USER_MAXIDLEN);
ktp->ktr_id[KTR_USER_MAXIDLEN-1] = '\0';
user_dta = (caddr_t) ((char *)ktp + sizeof(struct ktr_user));
if (copyin(addr, (void *) user_dta, len) != 0)
len = 0;
kth.ktr_buf = (void *)ktp;
kth.ktr_len = sizeof(struct ktr_user) + len;
error = ktrwrite(p, &kth);
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrmmsg(struct proc *p, const void *msgh, size_t size)
{
struct ktr_header kth;
struct ktr_mmsg *kp;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_MMSG);
kp = (struct ktr_mmsg *)msgh;
kth.ktr_buf = (caddr_t)kp;
kth.ktr_len = size;
error = ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
int
ktrmool(struct proc *p, const void *kaddr, size_t size, const void *uaddr)
{
struct ktr_header kth;
struct ktr_mool *kp;
struct ktr_mool *buf;
int error;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_MOOL);
kp = malloc(size + sizeof(*kp), M_TEMP, M_WAITOK);
kp->uaddr = uaddr;
kp->size = size;
buf = kp + 1; /* Skip uaddr and size */
(void)memcpy(buf, kaddr, size);
kth.ktr_buf = (caddr_t)kp;
kth.ktr_len = size + sizeof(*kp);
error = ktrwrite(p, &kth);
free(kp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return error;
}
/* Interface and common routines */
int
ktrace_common(struct proc *curp, int ops, int facs, int pid, struct file *fp)
{
int ret = 0;
int error = 0;
int one = 1;
int descend;
struct proc *p;
struct pgrp *pg;
curp->p_traceflag |= KTRFAC_ACTIVE;
descend = ops & KTRFLAG_DESCEND;
facs = facs & ~((unsigned) KTRFAC_ROOT);
/*
* Clear all uses of the tracefile
*/
if (KTROP(ops) == KTROP_CLEARFILE) {
proclist_lock_read();
LIST_FOREACH(p, &allproc, p_list) {
if (ktrsamefile(p->p_tracep, fp)) {
if (ktrcanset(curp, p))
ktrderef(p);
else
error = EPERM;
}
}
proclist_unlock_read();
goto done;
}
/*
* Mark fp non-blocking, to avoid problems from possible deadlocks.
*/
if (fp != NULL) {
fp->f_flag |= FNONBLOCK;
(*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&one, curp);
}
/*
* need something to (un)trace (XXX - why is this here?)
*/
if (!facs) {
error = EINVAL;
goto done;
}
/*
* do it
*/
if (pid < 0) {
/*
* by process group
*/
pg = pg_find(-pid, PFIND_UNLOCK_FAIL);
if (pg == NULL) {
error = ESRCH;
goto done;
}
LIST_FOREACH(p, &pg->pg_members, p_pglist) {
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, fp);
else
ret |= ktrops(curp, p, ops, facs, fp);
}
} else {
/*
* by pid
*/
p = p_find(pid, PFIND_UNLOCK_FAIL);
if (p == NULL) {
error = ESRCH;
goto done;
}
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, fp);
else
ret |= ktrops(curp, p, ops, facs, fp);
}
proclist_unlock_read(); /* taken by p{g}_find */
if (!ret)
error = EPERM;
done:
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
/*
* ktrace system call
*/
/* ARGSUSED */
int
sys_fktrace(struct lwp *l, void *v, register_t *retval)
{
struct sys_fktrace_args /* {
syscallarg(int) fd;
syscallarg(int) ops;
syscallarg(int) facs;
syscallarg(int) pid;
} */ *uap = v;
struct proc *curp = l->l_proc;
struct file *fp = NULL;
struct filedesc *fdp = curp->p_fd;
int error;
if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
return (EBADF);
FILE_USE(fp);
if ((fp->f_flag & FWRITE) == 0)
error = EBADF;
else
error = ktrace_common(curp, SCARG(uap, ops),
SCARG(uap, facs), SCARG(uap, pid), fp);
FILE_UNUSE(fp, curp);
return error;
}
/*
* ktrace system call
*/
/* ARGSUSED */
int
sys_ktrace(struct lwp *l, void *v, register_t *retval)
{
struct sys_ktrace_args /* {
syscallarg(const char *) fname;
syscallarg(int) ops;
syscallarg(int) facs;
syscallarg(int) pid;
} */ *uap = v;
struct proc *curp = l->l_proc;
struct vnode *vp = NULL;
struct file *fp = NULL;
int fd;
int ops = SCARG(uap, ops);
int error = 0;
struct nameidata nd;
ops = KTROP(ops) | (ops & KTRFLAG_DESCEND);
curp->p_traceflag |= KTRFAC_ACTIVE;
if ((ops & KTROP_CLEAR) == 0) {
/*
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname),
curp);
if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
vp = nd.ni_vp;
VOP_UNLOCK(vp, 0);
if (vp->v_type != VREG) {
(void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (EACCES);
}
/*
* XXX This uses up a file descriptor slot in the
* tracing process for the duration of this syscall.
* This is not expected to be a problem. If
* falloc(NULL, ...) DTRT we could skip that part, but
* that would require changing its interface to allow
* the caller to pass in a ucred..
*
* This will FILE_USE the fp it returns, if any.
* Keep it in use until we return.
*/
if ((error = falloc(curp, &fp, &fd)) != 0)
goto done;
fp->f_flag = FWRITE|FAPPEND;
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
fp->f_data = (caddr_t)vp;
FILE_SET_MATURE(fp);
vp = NULL;
}
error = ktrace_common(curp, SCARG(uap, ops), SCARG(uap, facs),
SCARG(uap, pid), fp);
done:
if (vp != NULL)
(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
if (fp != NULL) {
FILE_UNUSE(fp, curp); /* release file */
fdrelease(curp, fd); /* release fd table slot */
}
return (error);
}
int
ktrops(struct proc *curp, struct proc *p, int ops, int facs,
struct file *fp)
{
if (!ktrcanset(curp, p))
return (0);
if (KTROP(ops) == KTROP_SET) {
if (p->p_tracep != fp) {
/*
* if trace file already in use, relinquish
*/
ktrderef(p);
p->p_tracep = fp;
ktradref(p);
}
p->p_traceflag |= facs;
if (curp->p_ucred->cr_uid == 0)
p->p_traceflag |= KTRFAC_ROOT;
} else {
/* KTROP_CLEAR */
if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
/* no more tracing */
ktrderef(p);
}
}
/*
* Emit an emulation record, every time there is a ktrace
* change/attach request.
*/
if (KTRPOINT(p, KTR_EMUL))
p->p_traceflag |= KTRFAC_TRC_EMUL;
#ifdef __HAVE_SYSCALL_INTERN
(*p->p_emul->e_syscall_intern)(p);
#endif
return (1);
}
int
ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs,
struct file *fp)
{
struct proc *p;
int ret = 0;
p = top;
for (;;) {
ret |= ktrops(curp, p, ops, facs, fp);
/*
* 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_FIRST(&p->p_children) != NULL) {
p = LIST_FIRST(&p->p_children);
continue;
}
for (;;) {
if (p == top)
return (ret);
if (LIST_NEXT(p, p_sibling) != NULL) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
/*NOTREACHED*/
}
int
ktrwrite(struct proc *p, struct ktr_header *kth)
{
struct uio auio;
struct iovec aiov[2];
int error, tries;
struct file *fp = p->p_tracep;
if (fp == NULL)
return 0;
if (p->p_traceflag & KTRFAC_TRC_EMUL) {
/* Add emulation trace before first entry for this process */
p->p_traceflag &= ~KTRFAC_TRC_EMUL;
if ((error = ktremul(p)) != 0)
return error;
}
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_procp = (struct proc *)0;
if (kth->ktr_len > 0) {
auio.uio_iovcnt++;
aiov[1].iov_base = (void *)kth->ktr_buf;
aiov[1].iov_len = kth->ktr_len;
auio.uio_resid += kth->ktr_len;
}
simple_lock(&fp->f_slock);
FILE_USE(fp);
tries = 0;
do {
error = (*fp->f_ops->fo_write)(fp, &fp->f_offset, &auio,
fp->f_cred, FOF_UPDATE_OFFSET);
tries++;
if (error == EWOULDBLOCK)
preempt(1);
} while ((error == EWOULDBLOCK) && (tries < 3));
FILE_UNUSE(fp, NULL);
if (__predict_true(error == 0))
return (0);
/*
* If error encountered, give up tracing on this vnode. Don't report
* EPIPE as this can easily happen with fktrace()/ktruss.
*/
if (error != EPIPE)
log(LOG_NOTICE,
"ktrace write failed, errno %d, tracing stopped\n",
error);
proclist_lock_read();
LIST_FOREACH(p, &allproc, p_list) {
if (ktrsamefile(p->p_tracep, fp))
ktrderef(p);
}
proclist_unlock_read();
return (error);
}
/*
* 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.
*
* TODO: check groups. use caller effective gid.
*/
int
ktrcanset(struct proc *callp, struct proc *targetp)
{
struct pcred *caller = callp->p_cred;
struct pcred *target = targetp->p_cred;
if ((caller->pc_ucred->cr_uid == target->p_ruid &&
target->p_ruid == target->p_svuid &&
caller->p_rgid == target->p_rgid && /* XXX */
target->p_rgid == target->p_svgid &&
(targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
(targetp->p_flag & P_SUGID) == 0) ||
caller->pc_ucred->cr_uid == 0)
return (1);
return (0);
}
#endif /* KTRACE */
/*
* Put user defined entry to ktrace records.
*/
int
sys_utrace(struct lwp *l, void *v, register_t *retval)
{
#ifdef KTRACE
struct sys_utrace_args /* {
syscallarg(const char *) label;
syscallarg(void *) addr;
syscallarg(size_t) len;
} */ *uap = v;
struct proc *p = l->l_proc;
if (!KTRPOINT(p, KTR_USER))
return (0);
if (SCARG(uap, len) > KTR_USER_MAXLEN)
return (EINVAL);
ktruser(p, SCARG(uap, label), SCARG(uap, addr), SCARG(uap, len), 1);
return (0);
#else /* !KTRACE */
return ENOSYS;
#endif /* KTRACE */
}