1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 *
7 * @(#)kern_ktrace.c 8.5 (Berkeley) 05/14/95
8 */
9
10 #ifdef KTRACE
11
12 #include <sys/param.h>
13 #include <sys/systm.h>
14 #include <sys/proc.h>
15 #include <sys/file.h>
16 #include <sys/namei.h>
17 #include <sys/vnode.h>
18 #include <sys/ktrace.h>
19 #include <sys/malloc.h>
20 #include <sys/syslog.h>
21
22 #include <sys/mount.h>
23 #include <sys/syscallargs.h>
24
25 struct ktr_header *
ktrgetheader(type)26 ktrgetheader(type)
27 int type;
28 {
29 register struct ktr_header *kth;
30 struct proc *p = curproc; /* XXX */
31
32 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
33 M_TEMP, M_WAITOK);
34 kth->ktr_type = type;
35 microtime(&kth->ktr_time);
36 kth->ktr_pid = p->p_pid;
37 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
38 return (kth);
39 }
40
41 void
ktrsyscall(vp,code,argsize,args)42 ktrsyscall(vp, code, argsize, args)
43 struct vnode *vp;
44 int code, argsize;
45 register_t args[];
46 {
47 struct ktr_header *kth;
48 struct ktr_syscall *ktp;
49 register len = sizeof(struct ktr_syscall) + argsize;
50 struct proc *p = curproc; /* XXX */
51 register_t *argp;
52 int i;
53
54 p->p_traceflag |= KTRFAC_ACTIVE;
55 kth = ktrgetheader(KTR_SYSCALL);
56 MALLOC(ktp, struct ktr_syscall *, len, M_TEMP, M_WAITOK);
57 ktp->ktr_code = code;
58 ktp->ktr_argsize = argsize;
59 argp = (register_t *)((char *)ktp + sizeof(struct ktr_syscall));
60 for (i = 0; i < (argsize / sizeof *argp); i++)
61 *argp++ = args[i];
62 kth->ktr_buf = (caddr_t)ktp;
63 kth->ktr_len = len;
64 ktrwrite(vp, kth);
65 FREE(ktp, M_TEMP);
66 FREE(kth, M_TEMP);
67 p->p_traceflag &= ~KTRFAC_ACTIVE;
68 }
69
70 void
ktrsysret(vp,code,error,retval)71 ktrsysret(vp, code, error, retval)
72 struct vnode *vp;
73 int code, error, retval;
74 {
75 struct ktr_header *kth;
76 struct ktr_sysret ktp;
77 struct proc *p = curproc; /* XXX */
78
79 p->p_traceflag |= KTRFAC_ACTIVE;
80 kth = ktrgetheader(KTR_SYSRET);
81 ktp.ktr_code = code;
82 ktp.ktr_error = error;
83 ktp.ktr_retval = retval; /* what about val2 ? */
84
85 kth->ktr_buf = (caddr_t)&ktp;
86 kth->ktr_len = sizeof(struct ktr_sysret);
87
88 ktrwrite(vp, kth);
89 FREE(kth, M_TEMP);
90 p->p_traceflag &= ~KTRFAC_ACTIVE;
91 }
92
93 void
ktrnamei(vp,path)94 ktrnamei(vp, path)
95 struct vnode *vp;
96 char *path;
97 {
98 struct ktr_header *kth;
99 struct proc *p = curproc; /* XXX */
100
101 p->p_traceflag |= KTRFAC_ACTIVE;
102 kth = ktrgetheader(KTR_NAMEI);
103 kth->ktr_len = strlen(path);
104 kth->ktr_buf = path;
105
106 ktrwrite(vp, kth);
107 FREE(kth, M_TEMP);
108 p->p_traceflag &= ~KTRFAC_ACTIVE;
109 }
110
111 void
ktrgenio(vp,fd,rw,iov,len,error)112 ktrgenio(vp, fd, rw, iov, len, error)
113 struct vnode *vp;
114 int fd;
115 enum uio_rw rw;
116 register struct iovec *iov;
117 int len, error;
118 {
119 struct ktr_header *kth;
120 register struct ktr_genio *ktp;
121 register caddr_t cp;
122 register int resid = len, cnt;
123 struct proc *p = curproc; /* XXX */
124
125 if (error)
126 return;
127 p->p_traceflag |= KTRFAC_ACTIVE;
128 kth = ktrgetheader(KTR_GENIO);
129 MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len,
130 M_TEMP, M_WAITOK);
131 ktp->ktr_fd = fd;
132 ktp->ktr_rw = rw;
133 cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio));
134 while (resid > 0) {
135 if ((cnt = iov->iov_len) > resid)
136 cnt = resid;
137 if (copyin(iov->iov_base, cp, (unsigned)cnt))
138 goto done;
139 cp += cnt;
140 resid -= cnt;
141 iov++;
142 }
143 kth->ktr_buf = (caddr_t)ktp;
144 kth->ktr_len = sizeof (struct ktr_genio) + len;
145
146 ktrwrite(vp, kth);
147 done:
148 FREE(kth, M_TEMP);
149 FREE(ktp, M_TEMP);
150 p->p_traceflag &= ~KTRFAC_ACTIVE;
151 }
152
153 void
ktrpsig(vp,sig,action,mask,code)154 ktrpsig(vp, sig, action, mask, code)
155 struct vnode *vp;
156 int sig;
157 sig_t action;
158 int mask, code;
159 {
160 struct ktr_header *kth;
161 struct ktr_psig kp;
162 struct proc *p = curproc; /* XXX */
163
164 p->p_traceflag |= KTRFAC_ACTIVE;
165 kth = ktrgetheader(KTR_PSIG);
166 kp.signo = (char)sig;
167 kp.action = action;
168 kp.mask = mask;
169 kp.code = code;
170 kth->ktr_buf = (caddr_t)&kp;
171 kth->ktr_len = sizeof (struct ktr_psig);
172
173 ktrwrite(vp, kth);
174 FREE(kth, M_TEMP);
175 p->p_traceflag &= ~KTRFAC_ACTIVE;
176 }
177
178 void
ktrcsw(vp,out,user)179 ktrcsw(vp, out, user)
180 struct vnode *vp;
181 int out, user;
182 {
183 struct ktr_header *kth;
184 struct ktr_csw kc;
185 struct proc *p = curproc; /* XXX */
186
187 p->p_traceflag |= KTRFAC_ACTIVE;
188 kth = ktrgetheader(KTR_CSW);
189 kc.out = out;
190 kc.user = user;
191 kth->ktr_buf = (caddr_t)&kc;
192 kth->ktr_len = sizeof (struct ktr_csw);
193
194 ktrwrite(vp, kth);
195 FREE(kth, M_TEMP);
196 p->p_traceflag &= ~KTRFAC_ACTIVE;
197 }
198
199 /* Interface and common routines */
200
201 /*
202 * ktrace system call
203 */
204 /* ARGSUSED */
205 int
ktrace(curp,uap,retval)206 ktrace(curp, uap, retval)
207 struct proc *curp;
208 register struct ktrace_args /* {
209 syscallarg(char *) fname;
210 syscallarg(int) ops;
211 syscallarg(int) facs;
212 syscallarg(int) pid;
213 } */ *uap;
214 register_t *retval;
215 {
216 register struct vnode *vp = NULL;
217 register struct proc *p;
218 struct pgrp *pg;
219 int facs = SCARG(uap, facs) & ~KTRFAC_ROOT;
220 int ops = KTROP(SCARG(uap, ops));
221 int descend = SCARG(uap, ops) & KTRFLAG_DESCEND;
222 int ret = 0;
223 int error = 0;
224 struct nameidata nd;
225
226 curp->p_traceflag |= KTRFAC_ACTIVE;
227 if (ops != KTROP_CLEAR) {
228 /*
229 * an operation which requires a file argument.
230 */
231 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname),
232 curp);
233 if (error = vn_open(&nd, FREAD|FWRITE, 0)) {
234 curp->p_traceflag &= ~KTRFAC_ACTIVE;
235 return (error);
236 }
237 vp = nd.ni_vp;
238 VOP_UNLOCK(vp, 0, p);
239 if (vp->v_type != VREG) {
240 (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
241 curp->p_traceflag &= ~KTRFAC_ACTIVE;
242 return (EACCES);
243 }
244 }
245 /*
246 * Clear all uses of the tracefile
247 */
248 if (ops == KTROP_CLEARFILE) {
249 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
250 if (p->p_tracep == vp) {
251 if (ktrcanset(curp, p)) {
252 p->p_tracep = NULL;
253 p->p_traceflag = 0;
254 (void) vn_close(vp, FREAD|FWRITE,
255 p->p_ucred, p);
256 } else
257 error = EPERM;
258 }
259 }
260 goto done;
261 }
262 /*
263 * need something to (un)trace (XXX - why is this here?)
264 */
265 if (!facs) {
266 error = EINVAL;
267 goto done;
268 }
269 /*
270 * do it
271 */
272 if (SCARG(uap, pid) < 0) {
273 /*
274 * by process group
275 */
276 pg = pgfind(-SCARG(uap, pid));
277 if (pg == NULL) {
278 error = ESRCH;
279 goto done;
280 }
281 for (p = pg->pg_members.lh_first; p != 0; p = p->p_pglist.le_next)
282 if (descend)
283 ret |= ktrsetchildren(curp, p, ops, facs, vp);
284 else
285 ret |= ktrops(curp, p, ops, facs, vp);
286
287 } else {
288 /*
289 * by pid
290 */
291 p = pfind(SCARG(uap, pid));
292 if (p == NULL) {
293 error = ESRCH;
294 goto done;
295 }
296 if (descend)
297 ret |= ktrsetchildren(curp, p, ops, facs, vp);
298 else
299 ret |= ktrops(curp, p, ops, facs, vp);
300 }
301 if (!ret)
302 error = EPERM;
303 done:
304 if (vp != NULL)
305 (void) vn_close(vp, FWRITE, curp->p_ucred, curp);
306 curp->p_traceflag &= ~KTRFAC_ACTIVE;
307 return (error);
308 }
309
310 int
ktrops(curp,p,ops,facs,vp)311 ktrops(curp, p, ops, facs, vp)
312 struct proc *p, *curp;
313 int ops, facs;
314 struct vnode *vp;
315 {
316
317 if (!ktrcanset(curp, p))
318 return (0);
319 if (ops == KTROP_SET) {
320 if (p->p_tracep != vp) {
321 /*
322 * if trace file already in use, relinquish
323 */
324 if (p->p_tracep != NULL)
325 vrele(p->p_tracep);
326 VREF(vp);
327 p->p_tracep = vp;
328 }
329 p->p_traceflag |= facs;
330 if (curp->p_ucred->cr_uid == 0)
331 p->p_traceflag |= KTRFAC_ROOT;
332 } else {
333 /* KTROP_CLEAR */
334 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
335 /* no more tracing */
336 p->p_traceflag = 0;
337 if (p->p_tracep != NULL) {
338 vrele(p->p_tracep);
339 p->p_tracep = NULL;
340 }
341 }
342 }
343
344 return (1);
345 }
346
347 ktrsetchildren(curp, top, ops, facs, vp)
348 struct proc *curp, *top;
349 int ops, facs;
350 struct vnode *vp;
351 {
352 register struct proc *p;
353 register int ret = 0;
354
355 p = top;
356 for (;;) {
357 ret |= ktrops(curp, p, ops, facs, vp);
358 /*
359 * If this process has children, descend to them next,
360 * otherwise do any siblings, and if done with this level,
361 * follow back up the tree (but not past top).
362 */
363 if (p->p_children.lh_first)
364 p = p->p_children.lh_first;
365 else for (;;) {
366 if (p == top)
367 return (ret);
368 if (p->p_sibling.le_next) {
369 p = p->p_sibling.le_next;
370 break;
371 }
372 p = p->p_pptr;
373 }
374 }
375 /*NOTREACHED*/
376 }
377
378 ktrwrite(vp, kth)
379 struct vnode *vp;
380 register struct ktr_header *kth;
381 {
382 struct uio auio;
383 struct iovec aiov[2];
384 register struct proc *p = curproc; /* XXX */
385 int error;
386
387 if (vp == NULL)
388 return;
389 auio.uio_iov = &aiov[0];
390 auio.uio_offset = 0;
391 auio.uio_segflg = UIO_SYSSPACE;
392 auio.uio_rw = UIO_WRITE;
393 aiov[0].iov_base = (caddr_t)kth;
394 aiov[0].iov_len = sizeof(struct ktr_header);
395 auio.uio_resid = sizeof(struct ktr_header);
396 auio.uio_iovcnt = 1;
397 auio.uio_procp = (struct proc *)0;
398 if (kth->ktr_len > 0) {
399 auio.uio_iovcnt++;
400 aiov[1].iov_base = kth->ktr_buf;
401 aiov[1].iov_len = kth->ktr_len;
402 auio.uio_resid += kth->ktr_len;
403 }
404 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
405 error = VOP_WRITE(vp, &auio, IO_UNIT|IO_APPEND, p->p_ucred);
406 VOP_UNLOCK(vp, 0, p);
407 if (!error)
408 return;
409 /*
410 * If error encountered, give up tracing on this vnode.
411 */
412 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
413 error);
414 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
415 if (p->p_tracep == vp) {
416 p->p_tracep = NULL;
417 p->p_traceflag = 0;
418 vrele(vp);
419 }
420 }
421 }
422
423 /*
424 * Return true if caller has permission to set the ktracing state
425 * of target. Essentially, the target can't possess any
426 * more permissions than the caller. KTRFAC_ROOT signifies that
427 * root previously set the tracing status on the target process, and
428 * so, only root may further change it.
429 *
430 * TODO: check groups. use caller effective gid.
431 */
432 ktrcanset(callp, targetp)
433 struct proc *callp, *targetp;
434 {
435 register struct pcred *caller = callp->p_cred;
436 register struct pcred *target = targetp->p_cred;
437
438 if ((caller->pc_ucred->cr_uid == target->p_ruid &&
439 target->p_ruid == target->p_svuid &&
440 caller->p_rgid == target->p_rgid && /* XXX */
441 target->p_rgid == target->p_svgid &&
442 (targetp->p_traceflag & KTRFAC_ROOT) == 0) ||
443 caller->pc_ucred->cr_uid == 0)
444 return (1);
445
446 return (0);
447 }
448
449 #endif
450