1 /* $NetBSD: sys_process.c,v 1.59 1998/02/10 14:09:47 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 "opt_uvm.h" 56 57 #include <sys/param.h> 58 #include <sys/systm.h> 59 #include <sys/proc.h> 60 #include <sys/errno.h> 61 #include <sys/ptrace.h> 62 #include <sys/uio.h> 63 #include <sys/user.h> 64 65 #include <sys/mount.h> 66 #include <sys/syscallargs.h> 67 68 #if defined(UVM) 69 #include <vm/vm.h> 70 #include <uvm/uvm_extern.h> 71 #endif 72 73 #include <machine/reg.h> 74 75 #include <miscfs/procfs/procfs.h> 76 77 /* Macros to clear/set/test flags. */ 78 #define SET(t, f) (t) |= (f) 79 #define CLR(t, f) (t) &= ~(f) 80 #define ISSET(t, f) ((t) & (f)) 81 82 /* 83 * Process debugging system call. 84 */ 85 int 86 sys_ptrace(p, v, retval) 87 struct proc *p; 88 void *v; 89 register_t *retval; 90 { 91 struct sys_ptrace_args /* { 92 syscallarg(int) req; 93 syscallarg(pid_t) pid; 94 syscallarg(caddr_t) addr; 95 syscallarg(int) data; 96 } */ *uap = v; 97 struct proc *t; /* target process */ 98 struct uio uio; 99 struct iovec iov; 100 int error, write; 101 102 /* "A foolish consistency..." XXX */ 103 if (SCARG(uap, req) == PT_TRACE_ME) 104 t = p; 105 else { 106 107 /* Find the process we're supposed to be operating on. */ 108 if ((t = pfind(SCARG(uap, pid))) == NULL) 109 return (ESRCH); 110 } 111 112 /* Make sure we can operate on it. */ 113 switch (SCARG(uap, req)) { 114 case PT_TRACE_ME: 115 /* Saying that you're being traced is always legal. */ 116 break; 117 118 case PT_ATTACH: 119 /* 120 * You can't attach to a process if: 121 * (1) it's the process that's doing the attaching, 122 */ 123 if (t->p_pid == p->p_pid) 124 return (EINVAL); 125 126 /* 127 * (2) it's already being traced, or 128 */ 129 if (ISSET(t->p_flag, P_TRACED)) 130 return (EBUSY); 131 132 /* 133 * (3) it's not owned by you, or is set-id on exec 134 * (unless you're root), or... 135 */ 136 if ((t->p_cred->p_ruid != p->p_cred->p_ruid || 137 ISSET(t->p_flag, P_SUGID)) && 138 (error = suser(p->p_ucred, &p->p_acflag)) != 0) 139 return (error); 140 141 /* 142 * (4) ...it's init, which controls the security level 143 * of the entire system, and the system was not 144 * compiled with permanently insecure mode turned 145 * on. 146 */ 147 if (t == initproc && securelevel > -1) 148 return (EPERM); 149 break; 150 151 case PT_READ_I: 152 case PT_READ_D: 153 case PT_WRITE_I: 154 case PT_WRITE_D: 155 case PT_CONTINUE: 156 case PT_KILL: 157 case PT_DETACH: 158 #ifdef PT_STEP 159 case PT_STEP: 160 #endif 161 #ifdef PT_GETREGS 162 case PT_GETREGS: 163 #endif 164 #ifdef PT_SETREGS 165 case PT_SETREGS: 166 #endif 167 #ifdef PT_GETFPREGS 168 case PT_GETFPREGS: 169 #endif 170 #ifdef PT_SETFPREGS 171 case PT_SETFPREGS: 172 #endif 173 /* 174 * You can't do what you want to the process if: 175 * (1) It's not being traced at all, 176 */ 177 if (!ISSET(t->p_flag, P_TRACED)) 178 return (EPERM); 179 180 /* 181 * (2) it's being traced by procfs (which has 182 * different signal delivery semantics), 183 */ 184 if (ISSET(t->p_flag, P_FSTRACE)) 185 return (EBUSY); 186 187 /* 188 * (3) it's not being traced by _you_, or 189 */ 190 if (t->p_pptr != p) 191 return (EBUSY); 192 193 /* 194 * (4) it's not currently stopped. 195 */ 196 if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) 197 return (EBUSY); 198 break; 199 200 default: /* It was not a legal request. */ 201 return (EINVAL); 202 } 203 204 /* Do single-step fixup if needed. */ 205 FIX_SSTEP(t); 206 207 /* Now do the operation. */ 208 write = 0; 209 *retval = 0; 210 211 switch (SCARG(uap, req)) { 212 case PT_TRACE_ME: 213 /* Just set the trace flag. */ 214 SET(t->p_flag, P_TRACED); 215 t->p_oppid = t->p_pptr->p_pid; 216 return (0); 217 218 case PT_WRITE_I: /* XXX no seperate I and D spaces */ 219 case PT_WRITE_D: 220 write = 1; 221 case PT_READ_I: /* XXX no seperate I and D spaces */ 222 case PT_READ_D: 223 /* write = 0 done above. */ 224 iov.iov_base = 225 write ? (caddr_t)&SCARG(uap, data) : (caddr_t)retval; 226 iov.iov_len = sizeof(int); 227 uio.uio_iov = &iov; 228 uio.uio_iovcnt = 1; 229 uio.uio_offset = (off_t)(long)SCARG(uap, addr); 230 uio.uio_resid = sizeof(int); 231 uio.uio_segflg = UIO_SYSSPACE; 232 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 233 uio.uio_procp = p; 234 return (procfs_domem(p, t, NULL, &uio)); 235 236 #ifdef PT_STEP 237 case PT_STEP: 238 /* 239 * From the 4.4BSD PRM: 240 * "Execution continues as in request PT_CONTINUE; however 241 * as soon as possible after execution of at least one 242 * instruction, execution stops again. [ ... ]" 243 */ 244 #endif 245 case PT_CONTINUE: 246 case PT_DETACH: 247 /* 248 * From the 4.4BSD PRM: 249 * "The data argument is taken as a signal number and the 250 * child's execution continues at location addr as if it 251 * incurred that signal. Normally the signal number will 252 * be either 0 to indicate that the signal that caused the 253 * stop should be ignored, or that value fetched out of 254 * the process's image indicating which signal caused 255 * the stop. If addr is (int *)1 then execution continues 256 * from where it stopped." 257 */ 258 259 /* Check that the data is a valid signal number or zero. */ 260 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 261 return (EINVAL); 262 263 PHOLD(t); 264 265 #ifdef PT_STEP 266 /* 267 * Arrange for a single-step, if that's requested and possible. 268 */ 269 error = process_sstep(t, SCARG(uap, req) == PT_STEP); 270 if (error) 271 goto relebad; 272 #endif 273 274 /* If the address paramter is not (int *)1, set the pc. */ 275 if ((int *)SCARG(uap, addr) != (int *)1) 276 if ((error = process_set_pc(t, SCARG(uap, addr))) != 0) 277 goto relebad; 278 279 PRELE(t); 280 281 if (SCARG(uap, req) == PT_DETACH) { 282 /* give process back to original parent or init */ 283 if (t->p_oppid != t->p_pptr->p_pid) { 284 struct proc *pp; 285 286 pp = pfind(t->p_oppid); 287 proc_reparent(t, pp ? pp : initproc); 288 } 289 290 /* not being traced any more */ 291 t->p_oppid = 0; 292 CLR(t->p_flag, P_TRACED|P_WAITED); 293 } 294 295 sendsig: 296 /* Finally, deliver the requested signal (or none). */ 297 if (t->p_stat == SSTOP) { 298 t->p_xstat = SCARG(uap, data); 299 setrunnable(t); 300 } else { 301 if (SCARG(uap, data) != 0) 302 psignal(t, SCARG(uap, data)); 303 } 304 return (0); 305 306 relebad: 307 PRELE(t); 308 return (error); 309 310 case PT_KILL: 311 /* just send the process a KILL signal. */ 312 SCARG(uap, data) = SIGKILL; 313 goto sendsig; /* in PT_CONTINUE, above. */ 314 315 case PT_ATTACH: 316 /* 317 * Go ahead and set the trace flag. 318 * Save the old parent (it's reset in 319 * _DETACH, and also in kern_exit.c:wait4() 320 * Reparent the process so that the tracing 321 * proc gets to see all the action. 322 * Stop the target. 323 */ 324 SET(t->p_flag, P_TRACED); 325 t->p_oppid = t->p_pptr->p_pid; 326 if (t->p_pptr != p) 327 proc_reparent(t, p); 328 SCARG(uap, data) = SIGSTOP; 329 goto sendsig; 330 331 #ifdef PT_SETREGS 332 case PT_SETREGS: 333 write = 1; 334 #endif 335 #ifdef PT_GETREGS 336 case PT_GETREGS: 337 /* write = 0 done above. */ 338 #endif 339 #if defined(PT_SETREGS) || defined(PT_GETREGS) 340 if (!procfs_validregs(t)) 341 return (EINVAL); 342 else { 343 iov.iov_base = SCARG(uap, addr); 344 iov.iov_len = sizeof(struct reg); 345 uio.uio_iov = &iov; 346 uio.uio_iovcnt = 1; 347 uio.uio_offset = 0; 348 uio.uio_resid = sizeof(struct reg); 349 uio.uio_segflg = UIO_USERSPACE; 350 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 351 uio.uio_procp = p; 352 return (procfs_doregs(p, t, NULL, &uio)); 353 } 354 #endif 355 356 #ifdef PT_SETFPREGS 357 case PT_SETFPREGS: 358 write = 1; 359 #endif 360 #ifdef PT_GETFPREGS 361 case PT_GETFPREGS: 362 /* write = 0 done above. */ 363 #endif 364 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 365 if (!procfs_validfpregs(t)) 366 return (EINVAL); 367 else { 368 iov.iov_base = SCARG(uap, addr); 369 iov.iov_len = sizeof(struct fpreg); 370 uio.uio_iov = &iov; 371 uio.uio_iovcnt = 1; 372 uio.uio_offset = 0; 373 uio.uio_resid = sizeof(struct fpreg); 374 uio.uio_segflg = UIO_USERSPACE; 375 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 376 uio.uio_procp = p; 377 return (procfs_dofpregs(p, t, NULL, &uio)); 378 } 379 #endif 380 } 381 382 #ifdef DIAGNOSTIC 383 panic("ptrace: impossible"); 384 #endif 385 return 0; 386 } 387 388 int 389 trace_req(a1) 390 struct proc *a1; 391 { 392 393 /* just return 1 to keep other parts of the system happy */ 394 return (1); 395 } 396