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