1 /* $NetBSD: sys_process.c,v 1.71 2001/12/05 00:58:05 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1994 Christopher G. Demetriou. All rights reserved. 5 * Copyright (c) 1982, 1986, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93 42 */ 43 44 /* 45 * References: 46 * (1) Bach's "The Design of the UNIX Operating System", 47 * (2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution, 48 * (3) the "4.4BSD Programmer's Reference Manual" published 49 * by USENIX and O'Reilly & Associates. 50 * The 4.4BSD PRM does a reasonably good job of documenting what the various 51 * ptrace() requests should actually do, and its text is quoted several times 52 * in this file. 53 */ 54 55 #include <sys/cdefs.h> 56 __KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.71 2001/12/05 00:58:05 thorpej Exp $"); 57 58 #include <sys/param.h> 59 #include <sys/systm.h> 60 #include <sys/proc.h> 61 #include <sys/errno.h> 62 #include <sys/ptrace.h> 63 #include <sys/uio.h> 64 #include <sys/user.h> 65 66 #include <sys/mount.h> 67 #include <sys/syscallargs.h> 68 69 #include <uvm/uvm_extern.h> 70 71 #include <machine/reg.h> 72 73 #include <miscfs/procfs/procfs.h> 74 75 /* Macros to clear/set/test flags. */ 76 #define SET(t, f) (t) |= (f) 77 #define CLR(t, f) (t) &= ~(f) 78 #define ISSET(t, f) ((t) & (f)) 79 80 /* 81 * Process debugging system call. 82 */ 83 int 84 sys_ptrace(p, v, retval) 85 struct proc *p; 86 void *v; 87 register_t *retval; 88 { 89 struct sys_ptrace_args /* { 90 syscallarg(int) req; 91 syscallarg(pid_t) pid; 92 syscallarg(caddr_t) addr; 93 syscallarg(int) data; 94 } */ *uap = v; 95 struct proc *t; /* target process */ 96 struct uio uio; 97 struct iovec iov; 98 int s, error, write, tmp; 99 100 /* "A foolish consistency..." XXX */ 101 if (SCARG(uap, req) == PT_TRACE_ME) 102 t = p; 103 else { 104 105 /* Find the process we're supposed to be operating on. */ 106 if ((t = pfind(SCARG(uap, pid))) == NULL) 107 return (ESRCH); 108 } 109 110 /* Make sure we can operate on it. */ 111 switch (SCARG(uap, req)) { 112 case PT_TRACE_ME: 113 /* Saying that you're being traced is always legal. */ 114 break; 115 116 case PT_ATTACH: 117 /* 118 * You can't attach to a process if: 119 * (1) it's the process that's doing the attaching, 120 */ 121 if (t->p_pid == p->p_pid) 122 return (EINVAL); 123 124 /* 125 * (2) it's a system process 126 */ 127 if (t->p_flag & P_SYSTEM) 128 return (EPERM); 129 130 /* 131 * (3) it's already being traced, or 132 */ 133 if (ISSET(t->p_flag, P_TRACED)) 134 return (EBUSY); 135 136 /* 137 * (4) it's not owned by you, or is set-id on exec 138 * (unless you're root), or... 139 */ 140 if ((t->p_cred->p_ruid != p->p_cred->p_ruid || 141 ISSET(t->p_flag, P_SUGID)) && 142 (error = suser(p->p_ucred, &p->p_acflag)) != 0) 143 return (error); 144 145 /* 146 * (5) ...it's init, which controls the security level 147 * of the entire system, and the system was not 148 * compiled with permanently insecure mode turned on 149 */ 150 if (t == initproc && securelevel > -1) 151 return (EPERM); 152 153 /* 154 * (6) the tracer is chrooted, and its root directory is 155 * not at or above the root directory of the tracee 156 */ 157 158 if (!proc_isunder(t, p)) 159 return EPERM; 160 break; 161 162 case PT_READ_I: 163 case PT_READ_D: 164 case PT_WRITE_I: 165 case PT_WRITE_D: 166 case PT_CONTINUE: 167 case PT_KILL: 168 case PT_DETACH: 169 #ifdef PT_STEP 170 case PT_STEP: 171 #endif 172 #ifdef PT_GETREGS 173 case PT_GETREGS: 174 #endif 175 #ifdef PT_SETREGS 176 case PT_SETREGS: 177 #endif 178 #ifdef PT_GETFPREGS 179 case PT_GETFPREGS: 180 #endif 181 #ifdef PT_SETFPREGS 182 case PT_SETFPREGS: 183 #endif 184 185 #ifdef __HAVE_PTRACE_MACHDEP 186 PTRACE_MACHDEP_REQUEST_CASES 187 #endif 188 189 /* 190 * You can't do what you want to the process if: 191 * (1) It's not being traced at all, 192 */ 193 if (!ISSET(t->p_flag, P_TRACED)) 194 return (EPERM); 195 196 /* 197 * (2) it's being traced by procfs (which has 198 * different signal delivery semantics), 199 */ 200 if (ISSET(t->p_flag, P_FSTRACE)) 201 return (EBUSY); 202 203 /* 204 * (3) it's not being traced by _you_, or 205 */ 206 if (t->p_pptr != p) 207 return (EBUSY); 208 209 /* 210 * (4) it's not currently stopped. 211 */ 212 if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) 213 return (EBUSY); 214 break; 215 216 default: /* It was not a legal request. */ 217 return (EINVAL); 218 } 219 220 /* Do single-step fixup if needed. */ 221 FIX_SSTEP(t); 222 223 /* Now do the operation. */ 224 write = 0; 225 *retval = 0; 226 tmp = 0; 227 228 switch (SCARG(uap, req)) { 229 case PT_TRACE_ME: 230 /* Just set the trace flag. */ 231 SET(t->p_flag, P_TRACED); 232 t->p_oppid = t->p_pptr->p_pid; 233 return (0); 234 235 case PT_WRITE_I: /* XXX no separate I and D spaces */ 236 case PT_WRITE_D: 237 write = 1; 238 tmp = SCARG(uap, data); 239 case PT_READ_I: /* XXX no separate I and D spaces */ 240 case PT_READ_D: 241 /* write = 0 done above. */ 242 iov.iov_base = (caddr_t)&tmp; 243 iov.iov_len = sizeof(tmp); 244 uio.uio_iov = &iov; 245 uio.uio_iovcnt = 1; 246 uio.uio_offset = (off_t)(long)SCARG(uap, addr); 247 uio.uio_resid = sizeof(tmp); 248 uio.uio_segflg = UIO_SYSSPACE; 249 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 250 uio.uio_procp = p; 251 error = procfs_domem(p, t, NULL, &uio); 252 if (!write) 253 *retval = tmp; 254 return (error); 255 256 #ifdef PT_STEP 257 case PT_STEP: 258 /* 259 * From the 4.4BSD PRM: 260 * "Execution continues as in request PT_CONTINUE; however 261 * as soon as possible after execution of at least one 262 * instruction, execution stops again. [ ... ]" 263 */ 264 #endif 265 case PT_CONTINUE: 266 case PT_DETACH: 267 /* 268 * From the 4.4BSD PRM: 269 * "The data argument is taken as a signal number and the 270 * child's execution continues at location addr as if it 271 * incurred that signal. Normally the signal number will 272 * be either 0 to indicate that the signal that caused the 273 * stop should be ignored, or that value fetched out of 274 * the process's image indicating which signal caused 275 * the stop. If addr is (int *)1 then execution continues 276 * from where it stopped." 277 */ 278 279 /* Check that the data is a valid signal number or zero. */ 280 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 281 return (EINVAL); 282 283 PHOLD(t); 284 285 #ifdef PT_STEP 286 /* 287 * Arrange for a single-step, if that's requested and possible. 288 */ 289 error = process_sstep(t, SCARG(uap, req) == PT_STEP); 290 if (error) 291 goto relebad; 292 #endif 293 294 /* If the address parameter is not (int *)1, set the pc. */ 295 if ((int *)SCARG(uap, addr) != (int *)1) 296 if ((error = process_set_pc(t, SCARG(uap, addr))) != 0) 297 goto relebad; 298 299 PRELE(t); 300 301 if (SCARG(uap, req) == PT_DETACH) { 302 /* give process back to original parent or init */ 303 if (t->p_oppid != t->p_pptr->p_pid) { 304 struct proc *pp; 305 306 pp = pfind(t->p_oppid); 307 proc_reparent(t, pp ? pp : initproc); 308 } 309 310 /* not being traced any more */ 311 t->p_oppid = 0; 312 CLR(t->p_flag, P_TRACED|P_WAITED); 313 } 314 315 sendsig: 316 /* Finally, deliver the requested signal (or none). */ 317 if (t->p_stat == SSTOP) { 318 t->p_xstat = SCARG(uap, data); 319 SCHED_LOCK(s); 320 setrunnable(t); 321 SCHED_UNLOCK(s); 322 } else { 323 if (SCARG(uap, data) != 0) 324 psignal(t, SCARG(uap, data)); 325 } 326 return (0); 327 328 relebad: 329 PRELE(t); 330 return (error); 331 332 case PT_KILL: 333 /* just send the process a KILL signal. */ 334 SCARG(uap, data) = SIGKILL; 335 goto sendsig; /* in PT_CONTINUE, above. */ 336 337 case PT_ATTACH: 338 /* 339 * Go ahead and set the trace flag. 340 * Save the old parent (it's reset in 341 * _DETACH, and also in kern_exit.c:wait4() 342 * Reparent the process so that the tracing 343 * proc gets to see all the action. 344 * Stop the target. 345 */ 346 SET(t->p_flag, P_TRACED); 347 t->p_oppid = t->p_pptr->p_pid; 348 if (t->p_pptr != p) 349 proc_reparent(t, p); 350 SCARG(uap, data) = SIGSTOP; 351 goto sendsig; 352 353 #ifdef PT_SETREGS 354 case PT_SETREGS: 355 write = 1; 356 #endif 357 #ifdef PT_GETREGS 358 case PT_GETREGS: 359 /* write = 0 done above. */ 360 #endif 361 #if defined(PT_SETREGS) || defined(PT_GETREGS) 362 if (!procfs_validregs(t, NULL)) 363 return (EINVAL); 364 else { 365 iov.iov_base = SCARG(uap, addr); 366 iov.iov_len = sizeof(struct reg); 367 uio.uio_iov = &iov; 368 uio.uio_iovcnt = 1; 369 uio.uio_offset = 0; 370 uio.uio_resid = sizeof(struct reg); 371 uio.uio_segflg = UIO_USERSPACE; 372 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 373 uio.uio_procp = p; 374 return (procfs_doregs(p, t, NULL, &uio)); 375 } 376 #endif 377 378 #ifdef PT_SETFPREGS 379 case PT_SETFPREGS: 380 write = 1; 381 #endif 382 #ifdef PT_GETFPREGS 383 case PT_GETFPREGS: 384 /* write = 0 done above. */ 385 #endif 386 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 387 if (!procfs_validfpregs(t, NULL)) 388 return (EINVAL); 389 else { 390 iov.iov_base = SCARG(uap, addr); 391 iov.iov_len = sizeof(struct fpreg); 392 uio.uio_iov = &iov; 393 uio.uio_iovcnt = 1; 394 uio.uio_offset = 0; 395 uio.uio_resid = sizeof(struct fpreg); 396 uio.uio_segflg = UIO_USERSPACE; 397 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 398 uio.uio_procp = p; 399 return (procfs_dofpregs(p, t, NULL, &uio)); 400 } 401 #endif 402 403 #ifdef __HAVE_PTRACE_MACHDEP 404 PTRACE_MACHDEP_REQUEST_CASES 405 return (ptrace_machdep_dorequest(p, t, 406 SCARG(uap, req), SCARG(uap, addr), 407 SCARG(uap, data))); 408 #endif 409 } 410 411 #ifdef DIAGNOSTIC 412 panic("ptrace: impossible"); 413 #endif 414 return 0; 415 } 416