1 /* $NetBSD: sys_process.c,v 1.62 2000/06/27 17:41:36 mrg 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/param.h> 56 #include <sys/systm.h> 57 #include <sys/proc.h> 58 #include <sys/errno.h> 59 #include <sys/ptrace.h> 60 #include <sys/uio.h> 61 #include <sys/user.h> 62 63 #include <sys/mount.h> 64 #include <sys/syscallargs.h> 65 66 #include <uvm/uvm_extern.h> 67 68 #include <machine/reg.h> 69 70 #include <miscfs/procfs/procfs.h> 71 72 /* Macros to clear/set/test flags. */ 73 #define SET(t, f) (t) |= (f) 74 #define CLR(t, f) (t) &= ~(f) 75 #define ISSET(t, f) ((t) & (f)) 76 77 /* 78 * Process debugging system call. 79 */ 80 int 81 sys_ptrace(p, v, retval) 82 struct proc *p; 83 void *v; 84 register_t *retval; 85 { 86 struct sys_ptrace_args /* { 87 syscallarg(int) req; 88 syscallarg(pid_t) pid; 89 syscallarg(caddr_t) addr; 90 syscallarg(int) data; 91 } */ *uap = v; 92 struct proc *t; /* target process */ 93 struct uio uio; 94 struct iovec iov; 95 int error, write; 96 97 /* "A foolish consistency..." XXX */ 98 if (SCARG(uap, req) == PT_TRACE_ME) 99 t = p; 100 else { 101 102 /* Find the process we're supposed to be operating on. */ 103 if ((t = pfind(SCARG(uap, pid))) == NULL) 104 return (ESRCH); 105 } 106 107 /* Make sure we can operate on it. */ 108 switch (SCARG(uap, req)) { 109 case PT_TRACE_ME: 110 /* Saying that you're being traced is always legal. */ 111 break; 112 113 case PT_ATTACH: 114 /* 115 * You can't attach to a process if: 116 * (1) it's the process that's doing the attaching, 117 */ 118 if (t->p_pid == p->p_pid) 119 return (EINVAL); 120 121 /* 122 * (2) it's already being traced, or 123 */ 124 if (ISSET(t->p_flag, P_TRACED)) 125 return (EBUSY); 126 127 /* 128 * (3) it's not owned by you, or is set-id on exec 129 * (unless you're root), or... 130 */ 131 if ((t->p_cred->p_ruid != p->p_cred->p_ruid || 132 ISSET(t->p_flag, P_SUGID)) && 133 (error = suser(p->p_ucred, &p->p_acflag)) != 0) 134 return (error); 135 136 /* 137 * (4) ...it's init, which controls the security level 138 * of the entire system, and the system was not 139 * compiled with permanently insecure mode turned 140 * on. 141 */ 142 if (t == initproc && securelevel > -1) 143 return (EPERM); 144 145 /* 146 * (4) the tracer is chrooted, and its root directory is 147 * not at or above the root directory of the tracee 148 */ 149 150 if (!proc_isunder(t, p)) 151 return EPERM; 152 break; 153 154 case PT_READ_I: 155 case PT_READ_D: 156 case PT_WRITE_I: 157 case PT_WRITE_D: 158 case PT_CONTINUE: 159 case PT_KILL: 160 case PT_DETACH: 161 #ifdef PT_STEP 162 case PT_STEP: 163 #endif 164 #ifdef PT_GETREGS 165 case PT_GETREGS: 166 #endif 167 #ifdef PT_SETREGS 168 case PT_SETREGS: 169 #endif 170 #ifdef PT_GETFPREGS 171 case PT_GETFPREGS: 172 #endif 173 #ifdef PT_SETFPREGS 174 case PT_SETFPREGS: 175 #endif 176 /* 177 * You can't do what you want to the process if: 178 * (1) It's not being traced at all, 179 */ 180 if (!ISSET(t->p_flag, P_TRACED)) 181 return (EPERM); 182 183 /* 184 * (2) it's being traced by procfs (which has 185 * different signal delivery semantics), 186 */ 187 if (ISSET(t->p_flag, P_FSTRACE)) 188 return (EBUSY); 189 190 /* 191 * (3) it's not being traced by _you_, or 192 */ 193 if (t->p_pptr != p) 194 return (EBUSY); 195 196 /* 197 * (4) it's not currently stopped. 198 */ 199 if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) 200 return (EBUSY); 201 break; 202 203 default: /* It was not a legal request. */ 204 return (EINVAL); 205 } 206 207 /* Do single-step fixup if needed. */ 208 FIX_SSTEP(t); 209 210 /* Now do the operation. */ 211 write = 0; 212 *retval = 0; 213 214 switch (SCARG(uap, req)) { 215 case PT_TRACE_ME: 216 /* Just set the trace flag. */ 217 SET(t->p_flag, P_TRACED); 218 t->p_oppid = t->p_pptr->p_pid; 219 return (0); 220 221 case PT_WRITE_I: /* XXX no seperate I and D spaces */ 222 case PT_WRITE_D: 223 write = 1; 224 case PT_READ_I: /* XXX no seperate I and D spaces */ 225 case PT_READ_D: 226 /* write = 0 done above. */ 227 iov.iov_base = 228 write ? (caddr_t)&SCARG(uap, data) : (caddr_t)retval; 229 iov.iov_len = sizeof(int); 230 uio.uio_iov = &iov; 231 uio.uio_iovcnt = 1; 232 uio.uio_offset = (off_t)(long)SCARG(uap, addr); 233 uio.uio_resid = sizeof(int); 234 uio.uio_segflg = UIO_SYSSPACE; 235 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 236 uio.uio_procp = p; 237 return (procfs_domem(p, t, NULL, &uio)); 238 239 #ifdef PT_STEP 240 case PT_STEP: 241 /* 242 * From the 4.4BSD PRM: 243 * "Execution continues as in request PT_CONTINUE; however 244 * as soon as possible after execution of at least one 245 * instruction, execution stops again. [ ... ]" 246 */ 247 #endif 248 case PT_CONTINUE: 249 case PT_DETACH: 250 /* 251 * From the 4.4BSD PRM: 252 * "The data argument is taken as a signal number and the 253 * child's execution continues at location addr as if it 254 * incurred that signal. Normally the signal number will 255 * be either 0 to indicate that the signal that caused the 256 * stop should be ignored, or that value fetched out of 257 * the process's image indicating which signal caused 258 * the stop. If addr is (int *)1 then execution continues 259 * from where it stopped." 260 */ 261 262 /* Check that the data is a valid signal number or zero. */ 263 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 264 return (EINVAL); 265 266 PHOLD(t); 267 268 #ifdef PT_STEP 269 /* 270 * Arrange for a single-step, if that's requested and possible. 271 */ 272 error = process_sstep(t, SCARG(uap, req) == PT_STEP); 273 if (error) 274 goto relebad; 275 #endif 276 277 /* If the address paramter is not (int *)1, set the pc. */ 278 if ((int *)SCARG(uap, addr) != (int *)1) 279 if ((error = process_set_pc(t, SCARG(uap, addr))) != 0) 280 goto relebad; 281 282 PRELE(t); 283 284 if (SCARG(uap, req) == PT_DETACH) { 285 /* give process back to original parent or init */ 286 if (t->p_oppid != t->p_pptr->p_pid) { 287 struct proc *pp; 288 289 pp = pfind(t->p_oppid); 290 proc_reparent(t, pp ? pp : initproc); 291 } 292 293 /* not being traced any more */ 294 t->p_oppid = 0; 295 CLR(t->p_flag, P_TRACED|P_WAITED); 296 } 297 298 sendsig: 299 /* Finally, deliver the requested signal (or none). */ 300 if (t->p_stat == SSTOP) { 301 t->p_xstat = SCARG(uap, data); 302 setrunnable(t); 303 } else { 304 if (SCARG(uap, data) != 0) 305 psignal(t, SCARG(uap, data)); 306 } 307 return (0); 308 309 relebad: 310 PRELE(t); 311 return (error); 312 313 case PT_KILL: 314 /* just send the process a KILL signal. */ 315 SCARG(uap, data) = SIGKILL; 316 goto sendsig; /* in PT_CONTINUE, above. */ 317 318 case PT_ATTACH: 319 /* 320 * Go ahead and set the trace flag. 321 * Save the old parent (it's reset in 322 * _DETACH, and also in kern_exit.c:wait4() 323 * Reparent the process so that the tracing 324 * proc gets to see all the action. 325 * Stop the target. 326 */ 327 SET(t->p_flag, P_TRACED); 328 t->p_oppid = t->p_pptr->p_pid; 329 if (t->p_pptr != p) 330 proc_reparent(t, p); 331 SCARG(uap, data) = SIGSTOP; 332 goto sendsig; 333 334 #ifdef PT_SETREGS 335 case PT_SETREGS: 336 write = 1; 337 #endif 338 #ifdef PT_GETREGS 339 case PT_GETREGS: 340 /* write = 0 done above. */ 341 #endif 342 #if defined(PT_SETREGS) || defined(PT_GETREGS) 343 if (!procfs_validregs(t)) 344 return (EINVAL); 345 else { 346 iov.iov_base = SCARG(uap, addr); 347 iov.iov_len = sizeof(struct reg); 348 uio.uio_iov = &iov; 349 uio.uio_iovcnt = 1; 350 uio.uio_offset = 0; 351 uio.uio_resid = sizeof(struct reg); 352 uio.uio_segflg = UIO_USERSPACE; 353 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 354 uio.uio_procp = p; 355 return (procfs_doregs(p, t, NULL, &uio)); 356 } 357 #endif 358 359 #ifdef PT_SETFPREGS 360 case PT_SETFPREGS: 361 write = 1; 362 #endif 363 #ifdef PT_GETFPREGS 364 case PT_GETFPREGS: 365 /* write = 0 done above. */ 366 #endif 367 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 368 if (!procfs_validfpregs(t)) 369 return (EINVAL); 370 else { 371 iov.iov_base = SCARG(uap, addr); 372 iov.iov_len = sizeof(struct fpreg); 373 uio.uio_iov = &iov; 374 uio.uio_iovcnt = 1; 375 uio.uio_offset = 0; 376 uio.uio_resid = sizeof(struct fpreg); 377 uio.uio_segflg = UIO_USERSPACE; 378 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 379 uio.uio_procp = p; 380 return (procfs_dofpregs(p, t, NULL, &uio)); 381 } 382 #endif 383 } 384 385 #ifdef DIAGNOSTIC 386 panic("ptrace: impossible"); 387 #endif 388 return 0; 389 } 390 391 int 392 trace_req(a1) 393 struct proc *a1; 394 { 395 396 /* just return 1 to keep other parts of the system happy */ 397 return (1); 398 } 399