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 * 4. 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 ASSERT_LWKT_TOKEN_HELD(&proc_token); 116 117 /* Can't trace a process that's currently exec'ing. */ 118 if ((p->p_flags & P_INEXEC) != 0) 119 return EAGAIN; 120 /* 121 * Authorization check: rely on normal debugging protection, except 122 * allow processes to disengage debugging on a process onto which 123 * they have previously attached, but no longer have permission to 124 * debug. 125 */ 126 if (op != PROCFS_CTL_DETACH) { 127 if (securelevel > 0 && p->p_pid == 1) 128 return (EPERM); 129 130 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 131 return (EPERM); 132 } 133 134 /* 135 * Attach - attaches the target process for debugging 136 * by the calling process. 137 */ 138 if (op == PROCFS_CTL_ATTACH) { 139 /* check whether already being traced */ 140 if (p->p_flags & P_TRACED) 141 return (EBUSY); 142 143 /* can't trace yourself! */ 144 if (p->p_pid == curp->p_pid) 145 return (EINVAL); 146 147 /* 148 * Go ahead and set the trace flag. 149 * Save the old parent (it's reset in 150 * _DETACH, and also in kern_exit.c:wait4() 151 * Reparent the process so that the tracing 152 * proc gets to see all the action. 153 * Stop the target. 154 */ 155 p->p_flags |= P_TRACED; 156 faultin(p); 157 p->p_xstat = 0; /* XXX ? */ 158 if (p->p_pptr != curp) { 159 p->p_oppid = p->p_pptr->p_pid; 160 proc_reparent(p, curp); 161 } 162 proc_stop(p); 163 return (0); 164 } 165 166 /* 167 * Target process must be stopped, owned by (curp) and 168 * be set up for tracing (P_TRACED flag set). 169 * Allow DETACH to take place at any time for sanity. 170 * Allow WAIT any time, of course. 171 */ 172 switch (op) { 173 case PROCFS_CTL_DETACH: 174 case PROCFS_CTL_WAIT: 175 break; 176 177 default: 178 if (!TRACE_WAIT_P(curp, p)) 179 return (EBUSY); 180 } 181 182 183 #ifdef FIX_SSTEP 184 /* 185 * do single-step fixup if needed 186 */ 187 FIX_SSTEP(lp); 188 #endif 189 190 /* 191 * Don't deliver any signal by default. 192 * To continue with a signal, just send 193 * the signal name to the ctl file 194 */ 195 p->p_xstat = 0; 196 197 switch (op) { 198 /* 199 * Detach. Cleans up the target process, reparent it if possible 200 * and set it running once more. 201 */ 202 case PROCFS_CTL_DETACH: 203 /* if not being traced, then this is a painless no-op */ 204 if ((p->p_flags & P_TRACED) == 0) 205 return (0); 206 207 /* not being traced any more */ 208 p->p_flags &= ~P_TRACED; 209 210 /* remove pending SIGTRAP, else the process will die */ 211 spin_lock(&lp->lwp_spin); 212 lwp_delsig(lp, SIGTRAP); 213 spin_unlock(&lp->lwp_spin); 214 215 /* give process back to original parent */ 216 if (p->p_oppid != p->p_pptr->p_pid) { 217 struct proc *pp; 218 219 pp = pfs_pfind(p->p_oppid); 220 if (pp) { 221 proc_reparent(p, pp); 222 pfs_pdone(pp); 223 } 224 } 225 226 p->p_oppid = 0; 227 p->p_flags &= ~P_WAITED; /* XXX ? */ 228 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 229 230 break; 231 232 /* 233 * Step. Let the target process execute a single instruction. 234 */ 235 case PROCFS_CTL_STEP: 236 LWPHOLD(lp); 237 error = procfs_sstep(lp); 238 LWPRELE(lp); 239 if (error) 240 return (error); 241 break; 242 243 /* 244 * Run. Let the target process continue running until a breakpoint 245 * or some other trap. 246 */ 247 case PROCFS_CTL_RUN: 248 break; 249 250 /* 251 * Wait for the target process to stop. 252 * If the target is not being traced then just wait 253 * to enter 254 */ 255 case PROCFS_CTL_WAIT: 256 error = 0; 257 if (p->p_flags & P_TRACED) { 258 while (error == 0 && 259 p->p_stat != SSTOP && 260 (p->p_flags & P_TRACED) && 261 (p->p_pptr == curp)) { 262 error = tsleep((caddr_t) p, 263 PCATCH, "procfsx", 0); 264 } 265 if (error == 0 && !TRACE_WAIT_P(curp, p)) 266 error = EBUSY; 267 } else { 268 while (error == 0 && p->p_stat != SSTOP) { 269 error = tsleep((caddr_t) p, 270 PCATCH, "procfs", 0); 271 } 272 } 273 return (error); 274 275 default: 276 panic("procfs_control"); 277 } 278 279 /* 280 * If the process is in a stopped state, make it runnable again. 281 * Do not set LWP_MP_BREAKTSLEEP - that is, do not break a tsleep 282 * that might be in progress. 283 */ 284 if (p->p_stat == SSTOP) 285 proc_unstop(p); 286 return (0); 287 } 288 289 int 290 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 291 struct uio *uio) 292 { 293 struct proc *p = lp->lwp_proc; 294 int xlen; 295 int error; 296 char msg[PROCFS_CTLLEN+1]; 297 vfs_namemap_t *nm; 298 299 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 300 ASSERT_LWKT_TOKEN_HELD(&proc_token); 301 302 if (uio->uio_rw != UIO_WRITE) 303 return (EOPNOTSUPP); 304 305 xlen = PROCFS_CTLLEN; 306 error = vfs_getuserstr(uio, msg, &xlen); 307 if (error) 308 return (error); 309 310 /* 311 * Map signal names into signal generation 312 * or debug control. Unknown commands and/or signals 313 * return EOPNOTSUPP. 314 * 315 * Sending a signal while the process is being debugged 316 * also has the side effect of letting the target continue 317 * to run. There is no way to single-step a signal delivery. 318 */ 319 error = EOPNOTSUPP; 320 321 nm = vfs_findname(ctlnames, msg, xlen); 322 if (nm) { 323 error = procfs_control(curp, lp, nm->nm_val); 324 } else { 325 nm = vfs_findname(signames, msg, xlen); 326 if (nm) { 327 if (TRACE_WAIT_P(curp, p)) { 328 p->p_xstat = nm->nm_val; 329 #ifdef FIX_SSTEP 330 FIX_SSTEP(lp); 331 #endif 332 /* 333 * Make the process runnable but do not 334 * break its tsleep. 335 */ 336 proc_unstop(p); 337 } else { 338 ksignal(p, nm->nm_val); 339 } 340 error = 0; 341 } 342 } 343 344 return (error); 345 } 346