| 1 | /* $NetBSD: procfs_ctl.c,v 1.48 2016/04/04 20:47:57 christos Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1993 |
| 5 | * The Regents of the University of California. All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to Berkeley by |
| 8 | * Jan-Simon Pendry. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * 3. Neither the name of the University nor the names of its contributors |
| 19 | * may be used to endorse or promote products derived from this software |
| 20 | * without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 32 | * SUCH DAMAGE. |
| 33 | * |
| 34 | * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94 |
| 35 | */ |
| 36 | |
| 37 | /* |
| 38 | * Copyright (c) 1993 Jan-Simon Pendry |
| 39 | * |
| 40 | * This code is derived from software contributed to Berkeley by |
| 41 | * Jan-Simon Pendry. |
| 42 | * |
| 43 | * Redistribution and use in source and binary forms, with or without |
| 44 | * modification, are permitted provided that the following conditions |
| 45 | * are met: |
| 46 | * 1. Redistributions of source code must retain the above copyright |
| 47 | * notice, this list of conditions and the following disclaimer. |
| 48 | * 2. Redistributions in binary form must reproduce the above copyright |
| 49 | * notice, this list of conditions and the following disclaimer in the |
| 50 | * documentation and/or other materials provided with the distribution. |
| 51 | * 3. All advertising materials mentioning features or use of this software |
| 52 | * must display the following acknowledgement: |
| 53 | * This product includes software developed by the University of |
| 54 | * California, Berkeley and its contributors. |
| 55 | * 4. Neither the name of the University nor the names of its contributors |
| 56 | * may be used to endorse or promote products derived from this software |
| 57 | * without specific prior written permission. |
| 58 | * |
| 59 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 60 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 61 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 62 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 63 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 64 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 65 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 66 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 67 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 68 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 69 | * SUCH DAMAGE. |
| 70 | * |
| 71 | * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94 |
| 72 | */ |
| 73 | |
| 74 | #include <sys/cdefs.h> |
| 75 | __KERNEL_RCSID(0, "$NetBSD: procfs_ctl.c,v 1.48 2016/04/04 20:47:57 christos Exp $" ); |
| 76 | |
| 77 | #include <sys/param.h> |
| 78 | #include <sys/systm.h> |
| 79 | #include <sys/time.h> |
| 80 | #include <sys/kernel.h> |
| 81 | #include <sys/proc.h> |
| 82 | #include <sys/vnode.h> |
| 83 | #include <sys/ioctl.h> |
| 84 | #include <sys/tty.h> |
| 85 | #include <sys/resource.h> |
| 86 | #include <sys/resourcevar.h> |
| 87 | #include <sys/signalvar.h> |
| 88 | #include <sys/kauth.h> |
| 89 | |
| 90 | #include <uvm/uvm_extern.h> |
| 91 | |
| 92 | #include <miscfs/procfs/procfs.h> |
| 93 | |
| 94 | #define PROCFS_CTL_ATTACH 1 |
| 95 | #define PROCFS_CTL_DETACH 2 |
| 96 | #define PROCFS_CTL_STEP 3 |
| 97 | #define PROCFS_CTL_RUN 4 |
| 98 | #define PROCFS_CTL_WAIT 5 |
| 99 | |
| 100 | static const vfs_namemap_t ctlnames[] = { |
| 101 | /* special /proc commands */ |
| 102 | { "attach" , PROCFS_CTL_ATTACH }, |
| 103 | { "detach" , PROCFS_CTL_DETACH }, |
| 104 | { "step" , PROCFS_CTL_STEP }, |
| 105 | { "run" , PROCFS_CTL_RUN }, |
| 106 | { "wait" , PROCFS_CTL_WAIT }, |
| 107 | { NULL, 0 }, |
| 108 | }; |
| 109 | |
| 110 | static const vfs_namemap_t signames[] = { |
| 111 | /* regular signal names */ |
| 112 | { "hup" , SIGHUP }, { "int" , SIGINT }, |
| 113 | { "quit" , SIGQUIT }, { "ill" , SIGILL }, |
| 114 | { "trap" , SIGTRAP }, { "abrt" , SIGABRT }, |
| 115 | { "iot" , SIGIOT }, { "emt" , SIGEMT }, |
| 116 | { "fpe" , SIGFPE }, { "kill" , SIGKILL }, |
| 117 | { "bus" , SIGBUS }, { "segv" , SIGSEGV }, |
| 118 | { "sys" , SIGSYS }, { "pipe" , SIGPIPE }, |
| 119 | { "alrm" , SIGALRM }, { "term" , SIGTERM }, |
| 120 | { "urg" , SIGURG }, { "stop" , SIGSTOP }, |
| 121 | { "tstp" , SIGTSTP }, { "cont" , SIGCONT }, |
| 122 | { "chld" , SIGCHLD }, { "ttin" , SIGTTIN }, |
| 123 | { "ttou" , SIGTTOU }, { "io" , SIGIO }, |
| 124 | { "xcpu" , SIGXCPU }, { "xfsz" , SIGXFSZ }, |
| 125 | { "vtalrm" , SIGVTALRM }, { "prof" , SIGPROF }, |
| 126 | { "winch" , SIGWINCH }, { "info" , SIGINFO }, |
| 127 | { "usr1" , SIGUSR1 }, { "usr2" , SIGUSR2 }, |
| 128 | { NULL, 0 }, |
| 129 | }; |
| 130 | |
| 131 | static int procfs_control(struct lwp *, struct lwp *, int, int, |
| 132 | struct pfsnode *); |
| 133 | |
| 134 | int |
| 135 | procfs_control(struct lwp *curl, struct lwp *l, int op, int sig, struct pfsnode *pfs) |
| 136 | { |
| 137 | struct proc *curp = curl->l_proc; |
| 138 | struct proc *p = l->l_proc; |
| 139 | int error = 0; |
| 140 | |
| 141 | mutex_enter(proc_lock); |
| 142 | mutex_enter(p->p_lock); |
| 143 | |
| 144 | switch (op) { |
| 145 | /* |
| 146 | * Attach - attaches the target process for debugging |
| 147 | * by the calling process. |
| 148 | */ |
| 149 | case PROCFS_CTL_ATTACH: |
| 150 | /* |
| 151 | * You can't attach to a process if: |
| 152 | * (1) it's the process that's doing the attaching, |
| 153 | */ |
| 154 | if (p->p_pid == curp->p_pid) { |
| 155 | error = EINVAL; |
| 156 | break; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * (2) it's already being traced, or |
| 161 | */ |
| 162 | if (ISSET(p->p_slflag, PSL_TRACED)) { |
| 163 | error = EBUSY; |
| 164 | break; |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * (3) the security model prevents it. |
| 169 | */ |
| 170 | if ((error = kauth_authorize_process(curl->l_cred, |
| 171 | KAUTH_PROCESS_PROCFS, p, pfs, |
| 172 | KAUTH_ARG(KAUTH_REQ_PROCESS_PROCFS_CTL), NULL)) != 0) |
| 173 | break; |
| 174 | |
| 175 | break; |
| 176 | |
| 177 | /* |
| 178 | * Target process must be stopped, owned by (curp) and |
| 179 | * be set up for tracing (PSL_TRACED flag set). |
| 180 | * Allow DETACH to take place at any time for sanity. |
| 181 | * Allow WAIT any time, of course. |
| 182 | * |
| 183 | * Note that the semantics of DETACH are different here |
| 184 | * from ptrace(2). |
| 185 | */ |
| 186 | case PROCFS_CTL_DETACH: |
| 187 | case PROCFS_CTL_WAIT: |
| 188 | /* |
| 189 | * You can't do what you want to the process if: |
| 190 | * (1) It's not being traced at all, |
| 191 | */ |
| 192 | if (!ISSET(p->p_slflag, PSL_TRACED)) { |
| 193 | error = EPERM; |
| 194 | break; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * (2) it's being traced by ptrace(2) (which has |
| 199 | * different signal delivery semantics), or |
| 200 | */ |
| 201 | if (!ISSET(p->p_slflag, PSL_FSTRACE)) { |
| 202 | error = EBUSY; |
| 203 | break; |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * (3) it's not being traced by _you_. |
| 208 | */ |
| 209 | if (p->p_pptr != curp) |
| 210 | error = EBUSY; |
| 211 | |
| 212 | break; |
| 213 | |
| 214 | default: |
| 215 | /* |
| 216 | * You can't do what you want to the process if: |
| 217 | * (1) It's not being traced at all, |
| 218 | */ |
| 219 | if (!ISSET(p->p_slflag, PSL_TRACED)) { |
| 220 | error = EPERM; |
| 221 | break; |
| 222 | } |
| 223 | |
| 224 | /* |
| 225 | * (2) it's being traced by ptrace(2) (which has |
| 226 | * different signal delivery semantics), |
| 227 | */ |
| 228 | if (!ISSET(p->p_slflag, PSL_FSTRACE)) { |
| 229 | error = EBUSY; |
| 230 | break; |
| 231 | } |
| 232 | |
| 233 | /* |
| 234 | * (3) it's not being traced by _you_, or |
| 235 | */ |
| 236 | if (p->p_pptr != curp) { |
| 237 | error = EBUSY; |
| 238 | break; |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * (4) it's not currently stopped. |
| 243 | */ |
| 244 | if (p->p_stat != SSTOP || !p->p_waited /* XXXSMP */) |
| 245 | error = EBUSY; |
| 246 | |
| 247 | break; |
| 248 | } |
| 249 | |
| 250 | if (error != 0) { |
| 251 | mutex_exit(p->p_lock); |
| 252 | mutex_exit(proc_lock); |
| 253 | return (error); |
| 254 | } |
| 255 | |
| 256 | /* Do single-step fixup if needed. */ |
| 257 | FIX_SSTEP(p); |
| 258 | |
| 259 | switch (op) { |
| 260 | case PROCFS_CTL_ATTACH: |
| 261 | /* |
| 262 | * Go ahead and set the trace flag. |
| 263 | * Save the old parent (it's reset in |
| 264 | * _DETACH, and also in kern_exit.c:wait4() |
| 265 | * Reparent the process so that the tracing |
| 266 | * proc gets to see all the action. |
| 267 | * Stop the target. |
| 268 | */ |
| 269 | SET(p->p_slflag, PSL_TRACED|PSL_FSTRACE); |
| 270 | p->p_opptr = p->p_pptr; |
| 271 | if (p->p_pptr != curp) { |
| 272 | if (p->p_pptr->p_lock < p->p_lock) { |
| 273 | if (!mutex_tryenter(p->p_pptr->p_lock)) { |
| 274 | mutex_exit(p->p_lock); |
| 275 | mutex_enter(p->p_pptr->p_lock); |
| 276 | } |
| 277 | } else if (p->p_pptr->p_lock > p->p_lock) { |
| 278 | mutex_enter(p->p_pptr->p_lock); |
| 279 | } |
| 280 | p->p_pptr->p_slflag |= PSL_CHTRACED; |
| 281 | proc_reparent(p, curp); |
| 282 | if (p->p_pptr->p_lock != p->p_lock) |
| 283 | mutex_exit(p->p_pptr->p_lock); |
| 284 | } |
| 285 | sig = SIGSTOP; |
| 286 | goto sendsig; |
| 287 | |
| 288 | #ifdef PT_STEP |
| 289 | case PROCFS_CTL_STEP: |
| 290 | /* |
| 291 | * Step. Let the target process execute a single instruction. |
| 292 | */ |
| 293 | #endif |
| 294 | case PROCFS_CTL_RUN: |
| 295 | case PROCFS_CTL_DETACH: |
| 296 | #ifdef PT_STEP |
| 297 | /* XXXAD locking? */ |
| 298 | error = process_sstep(l, op == PROCFS_CTL_STEP); |
| 299 | if (error) |
| 300 | break; |
| 301 | #endif |
| 302 | |
| 303 | if (op == PROCFS_CTL_DETACH) { |
| 304 | /* give process back to original parent */ |
| 305 | if (p->p_opptr != p->p_pptr) { |
| 306 | struct proc *pp = p->p_opptr; |
| 307 | proc_reparent(p, pp ? pp : initproc); |
| 308 | } |
| 309 | |
| 310 | /* not being traced any more */ |
| 311 | p->p_opptr = NULL; |
| 312 | CLR(p->p_slflag, PSL_TRACED|PSL_FSTRACE); |
| 313 | p->p_waited = 0; /* XXXSMP */ |
| 314 | } |
| 315 | |
| 316 | sendsig: |
| 317 | /* Finally, deliver the requested signal (or none). */ |
| 318 | lwp_lock(l); |
| 319 | if (l->l_stat == LSSTOP) { |
| 320 | p->p_xsig = sig; |
| 321 | /* setrunnable() will release the lock. */ |
| 322 | setrunnable(l); |
| 323 | } else { |
| 324 | lwp_unlock(l); |
| 325 | if (sig != 0) { |
| 326 | mutex_exit(p->p_lock); |
| 327 | psignal(p, sig); |
| 328 | mutex_enter(p->p_lock); |
| 329 | } |
| 330 | } |
| 331 | mutex_exit(p->p_lock); |
| 332 | mutex_exit(proc_lock); |
| 333 | return (error); |
| 334 | |
| 335 | case PROCFS_CTL_WAIT: |
| 336 | mutex_exit(p->p_lock); |
| 337 | mutex_exit(proc_lock); |
| 338 | |
| 339 | /* |
| 340 | * Wait for the target process to stop. |
| 341 | * XXXSMP WTF is this? |
| 342 | */ |
| 343 | while (l->l_stat != LSSTOP && P_ZOMBIE(p)) { |
| 344 | error = tsleep(l, PWAIT|PCATCH, "procfsx" , hz); |
| 345 | if (error) |
| 346 | break; |
| 347 | } |
| 348 | |
| 349 | return (error); |
| 350 | |
| 351 | default: |
| 352 | panic("procfs_ctl" ); |
| 353 | /* NOTREACHED */ |
| 354 | } |
| 355 | |
| 356 | mutex_exit(p->p_lock); |
| 357 | mutex_exit(proc_lock); |
| 358 | return (error); |
| 359 | } |
| 360 | |
| 361 | int |
| 362 | procfs_doctl( |
| 363 | struct lwp *curl, |
| 364 | struct lwp *l, |
| 365 | struct pfsnode *pfs, |
| 366 | struct uio *uio |
| 367 | ) |
| 368 | { |
| 369 | struct proc *p = l->l_proc; |
| 370 | char msg[PROCFS_CTLLEN+1]; |
| 371 | const vfs_namemap_t *nm; |
| 372 | int error; |
| 373 | int xlen; |
| 374 | |
| 375 | if (uio->uio_rw != UIO_WRITE) |
| 376 | return (EOPNOTSUPP); |
| 377 | |
| 378 | xlen = PROCFS_CTLLEN; |
| 379 | error = vfs_getuserstr(uio, msg, &xlen); |
| 380 | if (error) |
| 381 | return (error); |
| 382 | |
| 383 | /* |
| 384 | * Map signal names into signal generation |
| 385 | * or debug control. Unknown commands and/or signals |
| 386 | * return EOPNOTSUPP. |
| 387 | * |
| 388 | * Sending a signal while the process is being debugged |
| 389 | * also has the side effect of letting the target continue |
| 390 | * to run. There is no way to single-step a signal delivery. |
| 391 | */ |
| 392 | error = EOPNOTSUPP; |
| 393 | |
| 394 | nm = vfs_findname(ctlnames, msg, xlen); |
| 395 | if (nm) { |
| 396 | error = procfs_control(curl, l, nm->nm_val, 0, pfs); |
| 397 | } else { |
| 398 | nm = vfs_findname(signames, msg, xlen); |
| 399 | if (nm) { |
| 400 | if (ISSET(p->p_slflag, PSL_TRACED) && |
| 401 | p->p_pptr == p) |
| 402 | error = procfs_control(curl, l, PROCFS_CTL_RUN, |
| 403 | nm->nm_val, pfs); |
| 404 | else { |
| 405 | psignal(p, nm->nm_val); |
| 406 | error = 0; |
| 407 | } |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | return (error); |
| 412 | } |
| 413 | |