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 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/proc.h> 42 #include <sys/priv.h> 43 #include <sys/vnode.h> 44 #include <sys/ptrace.h> 45 #include <sys/signalvar.h> 46 #include <vfs/procfs/procfs.h> 47 48 #include <sys/signal2.h> 49 #include <sys/mplock2.h> 50 #include <sys/spinlock2.h> 51 52 #include <vm/vm.h> 53 54 #ifndef FIX_SSTEP 55 #define FIX_SSTEP(lp) 56 #endif 57 58 /* 59 * True iff process (p) is in trace wait state 60 * relative to process (curp) 61 */ 62 #define TRACE_WAIT_P(curp, p) \ 63 (((p)->p_stat == SSTOP) && \ 64 (p)->p_pptr == (curp) && \ 65 ((p)->p_flags & P_TRACED)) 66 67 #define PROCFS_CTL_ATTACH 1 68 #define PROCFS_CTL_DETACH 2 69 #define PROCFS_CTL_STEP 3 70 #define PROCFS_CTL_RUN 4 71 #define PROCFS_CTL_WAIT 5 72 73 static vfs_namemap_t ctlnames[] = { 74 /* special /proc commands */ 75 { "attach", PROCFS_CTL_ATTACH }, 76 { "detach", PROCFS_CTL_DETACH }, 77 { "step", PROCFS_CTL_STEP }, 78 { "run", PROCFS_CTL_RUN }, 79 { "wait", PROCFS_CTL_WAIT }, 80 { 0 }, 81 }; 82 83 static vfs_namemap_t signames[] = { 84 /* regular signal names */ 85 { "hup", SIGHUP }, { "int", SIGINT }, 86 { "quit", SIGQUIT }, { "ill", SIGILL }, 87 { "trap", SIGTRAP }, { "abrt", SIGABRT }, 88 { "iot", SIGIOT }, { "emt", SIGEMT }, 89 { "fpe", SIGFPE }, { "kill", SIGKILL }, 90 { "bus", SIGBUS }, { "segv", SIGSEGV }, 91 { "sys", SIGSYS }, { "pipe", SIGPIPE }, 92 { "alrm", SIGALRM }, { "term", SIGTERM }, 93 { "urg", SIGURG }, { "stop", SIGSTOP }, 94 { "tstp", SIGTSTP }, { "cont", SIGCONT }, 95 { "chld", SIGCHLD }, { "ttin", SIGTTIN }, 96 { "ttou", SIGTTOU }, { "io", SIGIO }, 97 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ }, 98 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF }, 99 { "winch", SIGWINCH }, { "info", SIGINFO }, 100 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 }, 101 { 0 }, 102 }; 103 104 static int procfs_control (struct proc *curp, struct lwp *lp, int op); 105 106 static int 107 procfs_control(struct proc *curp, struct lwp *lp, int op) 108 { 109 struct proc *p = lp->lwp_proc; 110 int error; 111 112 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 113 114 /* Can't trace a process that's currently exec'ing. */ 115 if ((p->p_flags & P_INEXEC) != 0) 116 return EAGAIN; 117 /* 118 * Authorization check: rely on normal debugging protection, except 119 * allow processes to disengage debugging on a process onto which 120 * they have previously attached, but no longer have permission to 121 * debug. 122 */ 123 if (op != PROCFS_CTL_DETACH) { 124 if (securelevel > 0 && p->p_pid == 1) 125 return (EPERM); 126 127 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 128 return (EPERM); 129 } 130 131 /* 132 * Attach - attaches the target process for debugging 133 * by the calling process. 134 */ 135 if (op == PROCFS_CTL_ATTACH) { 136 /* check whether already being traced */ 137 if (p->p_flags & P_TRACED) 138 return (EBUSY); 139 140 /* can't trace yourself! */ 141 if (p->p_pid == curp->p_pid) 142 return (EINVAL); 143 144 /* 145 * Go ahead and set the trace flag. 146 * Save the old parent (it's reset in 147 * _DETACH, and also in kern_exit.c:wait4() 148 * Reparent the process so that the tracing 149 * proc gets to see all the action. 150 * Stop the target. 151 */ 152 p->p_flags |= P_TRACED; 153 faultin(p); 154 p->p_xstat = 0; /* XXX ? */ 155 if (p->p_pptr != curp) { 156 p->p_oppid = p->p_pptr->p_pid; 157 proc_reparent(p, curp); 158 } 159 proc_stop(p, SSTOP); 160 return (0); 161 } 162 163 /* 164 * Target process must be stopped, owned by (curp) and 165 * be set up for tracing (P_TRACED flag set). 166 * Allow DETACH to take place at any time for sanity. 167 * Allow WAIT any time, of course. 168 */ 169 switch (op) { 170 case PROCFS_CTL_DETACH: 171 case PROCFS_CTL_WAIT: 172 break; 173 174 default: 175 if (!TRACE_WAIT_P(curp, p)) 176 return (EBUSY); 177 } 178 179 180 #ifdef FIX_SSTEP 181 /* 182 * do single-step fixup if needed 183 */ 184 FIX_SSTEP(lp); 185 #endif 186 187 /* 188 * Don't deliver any signal by default. 189 * To continue with a signal, just send 190 * the signal name to the ctl file 191 */ 192 p->p_xstat = 0; 193 194 switch (op) { 195 /* 196 * Detach. Cleans up the target process, reparent it if possible 197 * and set it running once more. 198 */ 199 case PROCFS_CTL_DETACH: 200 /* if not being traced, then this is a painless no-op */ 201 if ((p->p_flags & P_TRACED) == 0) 202 return (0); 203 204 /* not being traced any more */ 205 p->p_flags &= ~P_TRACED; 206 207 /* remove pending SIGTRAP, else the process will die */ 208 spin_lock(&lp->lwp_spin); 209 lwp_delsig(lp, SIGTRAP, 1); 210 spin_unlock(&lp->lwp_spin); 211 212 /* give process back to original parent */ 213 if (p->p_oppid != p->p_pptr->p_pid) { 214 struct proc *pp; 215 216 pp = pfs_pfind(p->p_oppid); 217 if (pp) { 218 proc_reparent(p, pp); 219 pfs_pdone(pp); 220 } 221 } 222 223 p->p_oppid = 0; 224 p->p_flags &= ~P_WAITED; /* XXX ? */ 225 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 226 227 break; 228 229 /* 230 * Step. Let the target process execute a single instruction. 231 */ 232 case PROCFS_CTL_STEP: 233 LWPHOLD(lp); 234 error = procfs_sstep(lp); 235 LWPRELE(lp); 236 if (error) 237 return (error); 238 break; 239 240 /* 241 * Run. Let the target process continue running until a breakpoint 242 * or some other trap. 243 */ 244 case PROCFS_CTL_RUN: 245 break; 246 247 /* 248 * Wait for the target process to stop. 249 * If the target is not being traced then just wait 250 * to enter 251 */ 252 case PROCFS_CTL_WAIT: 253 error = 0; 254 if (p->p_flags & P_TRACED) { 255 while (error == 0 && 256 p->p_stat != SSTOP && 257 (p->p_flags & P_TRACED) && 258 (p->p_pptr == curp)) { 259 error = tsleep((caddr_t) p, 260 PCATCH, "procfsx", 0); 261 } 262 if (error == 0 && !TRACE_WAIT_P(curp, p)) 263 error = EBUSY; 264 } else { 265 while (error == 0 && p->p_stat != SSTOP) { 266 error = tsleep((caddr_t) p, 267 PCATCH, "procfs", 0); 268 } 269 } 270 return (error); 271 272 default: 273 panic("procfs_control"); 274 } 275 276 /* 277 * If the process is in a stopped state, make it runnable again. 278 * Do not set LWP_MP_BREAKTSLEEP - that is, do not break a tsleep 279 * that might be in progress. 280 */ 281 if (p->p_stat == SSTOP) 282 proc_unstop(p, SSTOP); 283 return (0); 284 } 285 286 int 287 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 288 struct uio *uio) 289 { 290 struct proc *p = lp->lwp_proc; 291 int xlen; 292 int error; 293 char msg[PROCFS_CTLLEN+1]; 294 vfs_namemap_t *nm; 295 296 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 297 298 if (uio->uio_rw != UIO_WRITE) 299 return (EOPNOTSUPP); 300 301 xlen = PROCFS_CTLLEN; 302 error = vfs_getuserstr(uio, msg, &xlen); 303 if (error) 304 return (error); 305 306 /* 307 * Map signal names into signal generation 308 * or debug control. Unknown commands and/or signals 309 * return EOPNOTSUPP. 310 * 311 * Sending a signal while the process is being debugged 312 * also has the side effect of letting the target continue 313 * to run. There is no way to single-step a signal delivery. 314 */ 315 error = EOPNOTSUPP; 316 317 nm = vfs_findname(ctlnames, msg, xlen); 318 if (nm) { 319 error = procfs_control(curp, lp, nm->nm_val); 320 } else { 321 nm = vfs_findname(signames, msg, xlen); 322 if (nm) { 323 if (TRACE_WAIT_P(curp, p)) { 324 p->p_xstat = nm->nm_val; 325 #ifdef FIX_SSTEP 326 FIX_SSTEP(lp); 327 #endif 328 /* 329 * Make the process runnable but do not 330 * break its tsleep. 331 */ 332 proc_unstop(p, SSTOP); 333 } else { 334 ksignal(p, nm->nm_val); 335 } 336 error = 0; 337 } 338 } 339 340 return (error); 341 } 342