1 /* 2 * Copyright (c) 1993 Jan-Simon Pendry 3 * Copyright (c) 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Jan-Simon Pendry. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94 38 * 39 * From: 40 * $FreeBSD: src/sys/miscfs/procfs/procfs_ctl.c,v 1.20.2.2 2002/01/22 17:22:59 nectar Exp $ 41 * $DragonFly: src/sys/vfs/procfs/procfs_ctl.c,v 1.16 2007/03/12 21:08:15 corecode Exp $ 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/priv.h> 48 #include <sys/vnode.h> 49 #include <sys/ptrace.h> 50 #include <sys/signalvar.h> 51 #include <vfs/procfs/procfs.h> 52 53 #include <sys/signal2.h> 54 #include <sys/thread2.h> 55 #include <sys/mplock2.h> 56 #include <sys/spinlock2.h> 57 58 #include <vm/vm.h> 59 60 #ifndef FIX_SSTEP 61 #define FIX_SSTEP(lp) 62 #endif 63 64 /* 65 * True iff process (p) is in trace wait state 66 * relative to process (curp) 67 */ 68 #define TRACE_WAIT_P(curp, p) \ 69 (((p)->p_stat == SSTOP) && \ 70 (p)->p_pptr == (curp) && \ 71 ((p)->p_flags & P_TRACED)) 72 73 #define PROCFS_CTL_ATTACH 1 74 #define PROCFS_CTL_DETACH 2 75 #define PROCFS_CTL_STEP 3 76 #define PROCFS_CTL_RUN 4 77 #define PROCFS_CTL_WAIT 5 78 79 static vfs_namemap_t ctlnames[] = { 80 /* special /proc commands */ 81 { "attach", PROCFS_CTL_ATTACH }, 82 { "detach", PROCFS_CTL_DETACH }, 83 { "step", PROCFS_CTL_STEP }, 84 { "run", PROCFS_CTL_RUN }, 85 { "wait", PROCFS_CTL_WAIT }, 86 { 0 }, 87 }; 88 89 static vfs_namemap_t signames[] = { 90 /* regular signal names */ 91 { "hup", SIGHUP }, { "int", SIGINT }, 92 { "quit", SIGQUIT }, { "ill", SIGILL }, 93 { "trap", SIGTRAP }, { "abrt", SIGABRT }, 94 { "iot", SIGIOT }, { "emt", SIGEMT }, 95 { "fpe", SIGFPE }, { "kill", SIGKILL }, 96 { "bus", SIGBUS }, { "segv", SIGSEGV }, 97 { "sys", SIGSYS }, { "pipe", SIGPIPE }, 98 { "alrm", SIGALRM }, { "term", SIGTERM }, 99 { "urg", SIGURG }, { "stop", SIGSTOP }, 100 { "tstp", SIGTSTP }, { "cont", SIGCONT }, 101 { "chld", SIGCHLD }, { "ttin", SIGTTIN }, 102 { "ttou", SIGTTOU }, { "io", SIGIO }, 103 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ }, 104 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF }, 105 { "winch", SIGWINCH }, { "info", SIGINFO }, 106 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 }, 107 { 0 }, 108 }; 109 110 static int procfs_control (struct proc *curp, struct lwp *lp, int op); 111 112 static int 113 procfs_control(struct proc *curp, struct lwp *lp, int op) 114 { 115 struct proc *p = lp->lwp_proc; 116 int error; 117 118 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 119 ASSERT_LWKT_TOKEN_HELD(&proc_token); 120 121 /* Can't trace a process that's currently exec'ing. */ 122 if ((p->p_flags & P_INEXEC) != 0) 123 return EAGAIN; 124 /* 125 * Authorization check: rely on normal debugging protection, except 126 * allow processes to disengage debugging on a process onto which 127 * they have previously attached, but no longer have permission to 128 * debug. 129 */ 130 if (op != PROCFS_CTL_DETACH) { 131 if (securelevel > 0 && p->p_pid == 1) 132 return (EPERM); 133 134 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 135 return (EPERM); 136 } 137 138 /* 139 * Attach - attaches the target process for debugging 140 * by the calling process. 141 */ 142 if (op == PROCFS_CTL_ATTACH) { 143 /* check whether already being traced */ 144 if (p->p_flags & P_TRACED) 145 return (EBUSY); 146 147 /* can't trace yourself! */ 148 if (p->p_pid == curp->p_pid) 149 return (EINVAL); 150 151 /* 152 * Go ahead and set the trace flag. 153 * Save the old parent (it's reset in 154 * _DETACH, and also in kern_exit.c:wait4() 155 * Reparent the process so that the tracing 156 * proc gets to see all the action. 157 * Stop the target. 158 */ 159 p->p_flags |= P_TRACED; 160 faultin(p); 161 p->p_xstat = 0; /* XXX ? */ 162 if (p->p_pptr != curp) { 163 p->p_oppid = p->p_pptr->p_pid; 164 proc_reparent(p, curp); 165 } 166 proc_stop(p); 167 return (0); 168 } 169 170 /* 171 * Target process must be stopped, owned by (curp) and 172 * be set up for tracing (P_TRACED flag set). 173 * Allow DETACH to take place at any time for sanity. 174 * Allow WAIT any time, of course. 175 */ 176 switch (op) { 177 case PROCFS_CTL_DETACH: 178 case PROCFS_CTL_WAIT: 179 break; 180 181 default: 182 if (!TRACE_WAIT_P(curp, p)) 183 return (EBUSY); 184 } 185 186 187 #ifdef FIX_SSTEP 188 /* 189 * do single-step fixup if needed 190 */ 191 FIX_SSTEP(lp); 192 #endif 193 194 /* 195 * Don't deliver any signal by default. 196 * To continue with a signal, just send 197 * the signal name to the ctl file 198 */ 199 p->p_xstat = 0; 200 201 switch (op) { 202 /* 203 * Detach. Cleans up the target process, reparent it if possible 204 * and set it running once more. 205 */ 206 case PROCFS_CTL_DETACH: 207 /* if not being traced, then this is a painless no-op */ 208 if ((p->p_flags & P_TRACED) == 0) 209 return (0); 210 211 /* not being traced any more */ 212 p->p_flags &= ~P_TRACED; 213 214 /* remove pending SIGTRAP, else the process will die */ 215 spin_lock(&lp->lwp_spin); 216 lwp_delsig(lp, SIGTRAP); 217 spin_unlock(&lp->lwp_spin); 218 219 /* give process back to original parent */ 220 if (p->p_oppid != p->p_pptr->p_pid) { 221 struct proc *pp; 222 223 pp = pfs_pfind(p->p_oppid); 224 if (pp) { 225 proc_reparent(p, pp); 226 pfs_pdone(pp); 227 } 228 } 229 230 p->p_oppid = 0; 231 p->p_flags &= ~P_WAITED; /* XXX ? */ 232 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 233 234 break; 235 236 /* 237 * Step. Let the target process execute a single instruction. 238 */ 239 case PROCFS_CTL_STEP: 240 LWPHOLD(lp); 241 error = procfs_sstep(lp); 242 LWPRELE(lp); 243 if (error) 244 return (error); 245 break; 246 247 /* 248 * Run. Let the target process continue running until a breakpoint 249 * or some other trap. 250 */ 251 case PROCFS_CTL_RUN: 252 break; 253 254 /* 255 * Wait for the target process to stop. 256 * If the target is not being traced then just wait 257 * to enter 258 */ 259 case PROCFS_CTL_WAIT: 260 error = 0; 261 if (p->p_flags & P_TRACED) { 262 while (error == 0 && 263 p->p_stat != SSTOP && 264 (p->p_flags & P_TRACED) && 265 (p->p_pptr == curp)) { 266 error = tsleep((caddr_t) p, 267 PCATCH, "procfsx", 0); 268 } 269 if (error == 0 && !TRACE_WAIT_P(curp, p)) 270 error = EBUSY; 271 } else { 272 while (error == 0 && p->p_stat != SSTOP) { 273 error = tsleep((caddr_t) p, 274 PCATCH, "procfs", 0); 275 } 276 } 277 return (error); 278 279 default: 280 panic("procfs_control"); 281 } 282 283 /* 284 * If the process is in a stopped state, make it runnable again. 285 * Do not set LWP_MP_BREAKTSLEEP - that is, do not break a tsleep 286 * that might be in progress. 287 */ 288 if (p->p_stat == SSTOP) 289 proc_unstop(p); 290 return (0); 291 } 292 293 int 294 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 295 struct uio *uio) 296 { 297 struct proc *p = lp->lwp_proc; 298 int xlen; 299 int error; 300 char msg[PROCFS_CTLLEN+1]; 301 vfs_namemap_t *nm; 302 303 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 304 ASSERT_LWKT_TOKEN_HELD(&proc_token); 305 306 if (uio->uio_rw != UIO_WRITE) 307 return (EOPNOTSUPP); 308 309 xlen = PROCFS_CTLLEN; 310 error = vfs_getuserstr(uio, msg, &xlen); 311 if (error) 312 return (error); 313 314 /* 315 * Map signal names into signal generation 316 * or debug control. Unknown commands and/or signals 317 * return EOPNOTSUPP. 318 * 319 * Sending a signal while the process is being debugged 320 * also has the side effect of letting the target continue 321 * to run. There is no way to single-step a signal delivery. 322 */ 323 error = EOPNOTSUPP; 324 325 nm = vfs_findname(ctlnames, msg, xlen); 326 if (nm) { 327 error = procfs_control(curp, lp, nm->nm_val); 328 } else { 329 nm = vfs_findname(signames, msg, xlen); 330 if (nm) { 331 if (TRACE_WAIT_P(curp, p)) { 332 p->p_xstat = nm->nm_val; 333 #ifdef FIX_SSTEP 334 FIX_SSTEP(lp); 335 #endif 336 /* 337 * Make the process runnable but do not 338 * break its tsleep. 339 */ 340 proc_unstop(p); 341 } else { 342 ksignal(p, nm->nm_val); 343 } 344 error = 0; 345 } 346 } 347 348 return (error); 349 } 350