1 /* $NetBSD: sys_process.c,v 1.47 1995/02/09 05:19:18 mycroft 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 <machine/reg.h> 67 68 /* Macros to clear/set/test flags. */ 69 #define SET(t, f) (t) |= (f) 70 #define CLR(t, f) (t) &= ~(f) 71 #define ISSET(t, f) ((t) & (f)) 72 73 /* 74 * Process debugging system call. 75 */ 76 int 77 ptrace(p, uap, retval) 78 struct proc *p; 79 struct ptrace_args /* { 80 syscallarg(int) req; 81 syscallarg(pid_t) pid; 82 syscallarg(caddr_t) addr; 83 syscallarg(int) data; 84 } */ *uap; 85 register_t *retval; 86 { 87 struct proc *t; /* target process */ 88 struct uio uio; 89 struct iovec iov; 90 int error, write; 91 92 /* "A foolish consistency..." XXX */ 93 if (SCARG(uap, req) == PT_TRACE_ME) 94 t = p; 95 else { 96 /* Find the process we're supposed to be operating on. */ 97 if ((t = pfind(SCARG(uap, pid))) == NULL) 98 return (ESRCH); 99 } 100 101 /* Make sure we can operate on it. */ 102 switch (SCARG(uap, req)) { 103 case PT_TRACE_ME: 104 /* Saying that you're being traced is always legal. */ 105 break; 106 107 case PT_ATTACH: 108 /* 109 * You can't attach to a process if: 110 * (1) it's the process that's doing the attaching, 111 */ 112 if (t->p_pid == p->p_pid) 113 return (EINVAL); 114 115 /* 116 * (2) it's already being traced, or 117 */ 118 if (ISSET(t->p_flag, P_TRACED)) 119 return (EBUSY); 120 121 /* 122 * (3) it's not owned by you, or is set-id on exec 123 * (unless you're root). 124 */ 125 if ((t->p_cred->p_ruid != p->p_cred->p_ruid || 126 ISSET(t->p_flag, P_SUGID)) && 127 (error = suser(p->p_ucred, &p->p_acflag)) != 0) 128 return (error); 129 break; 130 131 case PT_READ_I: 132 case PT_READ_D: 133 case PT_WRITE_I: 134 case PT_WRITE_D: 135 case PT_CONTINUE: 136 case PT_KILL: 137 case PT_DETACH: 138 #ifdef PT_STEP 139 case PT_STEP: 140 #endif 141 #ifdef PT_GETREGS 142 case PT_GETREGS: 143 #endif 144 #ifdef PT_SETREGS 145 case PT_SETREGS: 146 #endif 147 #ifdef PT_GETFPREGS 148 case PT_GETFPREGS: 149 #endif 150 #ifdef PT_SETFPREGS 151 case PT_SETFPREGS: 152 #endif 153 /* 154 * You can't do what you want to the process if: 155 * (1) It's not being traced at all, 156 */ 157 if (!ISSET(t->p_flag, P_TRACED)) 158 return (EPERM); 159 160 /* 161 * (2) it's not being traced by _you_, or 162 */ 163 if (t->p_pptr != p) 164 return (EBUSY); 165 166 /* 167 * (3) it's not currently stopped. 168 */ 169 if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) 170 return (EBUSY); 171 break; 172 173 default: /* It was not a legal request. */ 174 return (EINVAL); 175 } 176 177 /* Do single-step fixup if needed. */ 178 FIX_SSTEP(t); 179 180 /* Now do the operation. */ 181 write = 0; 182 *retval = 0; 183 184 switch (SCARG(uap, req)) { 185 case PT_TRACE_ME: 186 /* Just set the trace flag. */ 187 SET(t->p_flag, P_TRACED); 188 t->p_oppid = t->p_pptr->p_pid; 189 return (0); 190 191 case PT_WRITE_I: /* XXX no seperate I and D spaces */ 192 case PT_WRITE_D: 193 write = 1; 194 case PT_READ_I: /* XXX no seperate I and D spaces */ 195 case PT_READ_D: 196 /* write = 0 done above. */ 197 iov.iov_base = 198 write ? (caddr_t)&SCARG(uap, data) : (caddr_t)retval; 199 iov.iov_len = sizeof(int); 200 uio.uio_iov = &iov; 201 uio.uio_iovcnt = 1; 202 uio.uio_offset = (off_t)(long)SCARG(uap, addr); 203 uio.uio_resid = sizeof(int); 204 uio.uio_segflg = UIO_SYSSPACE; 205 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 206 uio.uio_procp = p; 207 return (procfs_domem(p, t, NULL, &uio)); 208 209 #ifdef PT_STEP 210 case PT_STEP: 211 /* 212 * From the 4.4BSD PRM: 213 * "Execution continues as in request PT_CONTINUE; however 214 * as soon as possible after execution of at least one 215 * instruction, execution stops again. [ ... ]" 216 */ 217 #endif 218 case PT_CONTINUE: 219 case PT_DETACH: 220 /* 221 * From the 4.4BSD PRM: 222 * "The data argument is taken as a signal number and the 223 * child's execution continues at location addr as if it 224 * incurred that signal. Normally the signal number will 225 * be either 0 to indicate that the signal that caused the 226 * stop should be ignored, or that value fetched out of 227 * the process's image indicating which signal caused 228 * the stop. If addr is (int *)1 then execution continues 229 * from where it stopped." 230 */ 231 232 /* Check that the data is a valid signal number or zero. */ 233 if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) 234 return (EINVAL); 235 236 #ifdef PT_STEP 237 /* 238 * Arrange for a single-step, if that's requested and possible. 239 */ 240 if (error = process_sstep(t, SCARG(uap, req) == PT_STEP)) 241 return (error); 242 #endif 243 244 /* If the address paramter is not (int *)1, set the pc. */ 245 if ((int *)SCARG(uap, addr) != (int *)1) 246 if (error = process_set_pc(t, SCARG(uap, addr))) 247 return (error); 248 249 if (SCARG(uap, req) == PT_DETACH) { 250 /* give process back to original parent or init */ 251 if (t->p_oppid != t->p_pptr->p_pid) { 252 struct proc *pp; 253 254 pp = pfind(t->p_oppid); 255 proc_reparent(t, pp ? pp : initproc); 256 } 257 258 /* not being traced any more */ 259 t->p_oppid = 0; 260 CLR(t->p_flag, P_TRACED|P_WAITED); 261 } 262 263 /* Finally, deliver the requested signal (or none). */ 264 sendsig: 265 if (t->p_stat == SSTOP) { 266 t->p_xstat = SCARG(uap, data); 267 setrunnable(t); 268 } else { 269 if (SCARG(uap, data) != 0) 270 psignal(t, SCARG(uap, data)); 271 } 272 return (0); 273 274 case PT_KILL: 275 /* just send the process a KILL signal. */ 276 SCARG(uap, data) = SIGKILL; 277 goto sendsig; /* in PT_CONTINUE, above. */ 278 279 case PT_ATTACH: 280 /* 281 * As done in procfs: 282 * Go ahead and set the trace flag. 283 * Save the old parent (it's reset in 284 * _DETACH, and also in kern_exit.c:wait4() 285 * Reparent the process so that the tracing 286 * proc gets to see all the action. 287 * Stop the target. 288 */ 289 SET(t->p_flag, P_TRACED); 290 t->p_oppid = t->p_pptr->p_pid; 291 if (t->p_pptr != p) 292 proc_reparent(t, p); 293 t->p_xstat = 0; /* XXX ? */ 294 psignal(t, SIGSTOP); 295 return (0); 296 297 #ifdef PT_SETREGS 298 case PT_SETREGS: 299 write = 1; 300 #endif 301 #ifdef PT_GETREGS 302 case PT_GETREGS: 303 /* write = 0 done above. */ 304 #endif 305 #if defined(PT_SETREGS) || defined(PT_GETREGS) 306 if (!procfs_validregs(t)) 307 return (EINVAL); 308 else { 309 iov.iov_base = SCARG(uap, addr); 310 iov.iov_len = sizeof(struct reg); 311 uio.uio_iov = &iov; 312 uio.uio_iovcnt = 1; 313 uio.uio_offset = 0; 314 uio.uio_resid = sizeof(struct reg); 315 uio.uio_segflg = UIO_USERSPACE; 316 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 317 uio.uio_procp = p; 318 return (procfs_doregs(p, t, NULL, &uio)); 319 } 320 #endif 321 322 #ifdef PT_SETFPREGS 323 case PT_SETFPREGS: 324 write = 1; 325 #endif 326 #ifdef PT_GETFPREGS 327 case PT_GETFPREGS: 328 /* write = 0 done above. */ 329 #endif 330 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 331 if (!procfs_validfpregs(t)) 332 return (EINVAL); 333 else { 334 iov.iov_base = SCARG(uap, addr); 335 iov.iov_len = sizeof(struct fpreg); 336 uio.uio_iov = &iov; 337 uio.uio_iovcnt = 1; 338 uio.uio_offset = 0; 339 uio.uio_resid = sizeof(struct fpreg); 340 uio.uio_segflg = UIO_USERSPACE; 341 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 342 uio.uio_procp = p; 343 return (procfs_dofpregs(p, t, NULL, &uio)); 344 } 345 #endif 346 } 347 348 #ifdef DIAGNOSTIC 349 panic("ptrace: impossible"); 350 #endif 351 } 352 353 trace_req(a1) 354 struct proc *a1; 355 { 356 357 /* just return 1 to keep other parts of the system happy */ 358 return (1); 359 } 360