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 57 #include <vm/vm.h> 58 59 #ifndef FIX_SSTEP 60 #define FIX_SSTEP(lp) 61 #endif 62 63 /* 64 * True iff process (p) is in trace wait state 65 * relative to process (curp) 66 */ 67 #define TRACE_WAIT_P(curp, p) \ 68 (((p)->p_stat == SSTOP) && \ 69 (p)->p_pptr == (curp) && \ 70 ((p)->p_flag & P_TRACED)) 71 72 #define PROCFS_CTL_ATTACH 1 73 #define PROCFS_CTL_DETACH 2 74 #define PROCFS_CTL_STEP 3 75 #define PROCFS_CTL_RUN 4 76 #define PROCFS_CTL_WAIT 5 77 78 static vfs_namemap_t ctlnames[] = { 79 /* special /proc commands */ 80 { "attach", PROCFS_CTL_ATTACH }, 81 { "detach", PROCFS_CTL_DETACH }, 82 { "step", PROCFS_CTL_STEP }, 83 { "run", PROCFS_CTL_RUN }, 84 { "wait", PROCFS_CTL_WAIT }, 85 { 0 }, 86 }; 87 88 static vfs_namemap_t signames[] = { 89 /* regular signal names */ 90 { "hup", SIGHUP }, { "int", SIGINT }, 91 { "quit", SIGQUIT }, { "ill", SIGILL }, 92 { "trap", SIGTRAP }, { "abrt", SIGABRT }, 93 { "iot", SIGIOT }, { "emt", SIGEMT }, 94 { "fpe", SIGFPE }, { "kill", SIGKILL }, 95 { "bus", SIGBUS }, { "segv", SIGSEGV }, 96 { "sys", SIGSYS }, { "pipe", SIGPIPE }, 97 { "alrm", SIGALRM }, { "term", SIGTERM }, 98 { "urg", SIGURG }, { "stop", SIGSTOP }, 99 { "tstp", SIGTSTP }, { "cont", SIGCONT }, 100 { "chld", SIGCHLD }, { "ttin", SIGTTIN }, 101 { "ttou", SIGTTOU }, { "io", SIGIO }, 102 { "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ }, 103 { "vtalrm", SIGVTALRM }, { "prof", SIGPROF }, 104 { "winch", SIGWINCH }, { "info", SIGINFO }, 105 { "usr1", SIGUSR1 }, { "usr2", SIGUSR2 }, 106 { 0 }, 107 }; 108 109 static int procfs_control (struct proc *curp, struct lwp *lp, int op); 110 111 static int 112 procfs_control(struct proc *curp, struct lwp *lp, int op) 113 { 114 struct proc *p = lp->lwp_proc; 115 int error; 116 117 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 118 ASSERT_LWKT_TOKEN_HELD(&proc_token); 119 120 /* Can't trace a process that's currently exec'ing. */ 121 if ((p->p_flag & P_INEXEC) != 0) 122 return EAGAIN; 123 /* 124 * Authorization check: rely on normal debugging protection, except 125 * allow processes to disengage debugging on a process onto which 126 * they have previously attached, but no longer have permission to 127 * debug. 128 */ 129 if (op != PROCFS_CTL_DETACH) { 130 if (securelevel > 0 && p->p_pid == 1) 131 return (EPERM); 132 133 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 134 return (EPERM); 135 } 136 137 /* 138 * Attach - attaches the target process for debugging 139 * by the calling process. 140 */ 141 if (op == PROCFS_CTL_ATTACH) { 142 /* check whether already being traced */ 143 if (p->p_flag & P_TRACED) 144 return (EBUSY); 145 146 /* can't trace yourself! */ 147 if (p->p_pid == curp->p_pid) 148 return (EINVAL); 149 150 /* 151 * Go ahead and set the trace flag. 152 * Save the old parent (it's reset in 153 * _DETACH, and also in kern_exit.c:wait4() 154 * Reparent the process so that the tracing 155 * proc gets to see all the action. 156 * Stop the target. 157 */ 158 p->p_flag |= P_TRACED; 159 faultin(p); 160 p->p_xstat = 0; /* XXX ? */ 161 if (p->p_pptr != curp) { 162 p->p_oppid = p->p_pptr->p_pid; 163 proc_reparent(p, curp); 164 } 165 proc_stop(p); 166 return (0); 167 } 168 169 /* 170 * Target process must be stopped, owned by (curp) and 171 * be set up for tracing (P_TRACED flag set). 172 * Allow DETACH to take place at any time for sanity. 173 * Allow WAIT any time, of course. 174 */ 175 switch (op) { 176 case PROCFS_CTL_DETACH: 177 case PROCFS_CTL_WAIT: 178 break; 179 180 default: 181 if (!TRACE_WAIT_P(curp, p)) 182 return (EBUSY); 183 } 184 185 186 #ifdef FIX_SSTEP 187 /* 188 * do single-step fixup if needed 189 */ 190 FIX_SSTEP(lp); 191 #endif 192 193 /* 194 * Don't deliver any signal by default. 195 * To continue with a signal, just send 196 * the signal name to the ctl file 197 */ 198 p->p_xstat = 0; 199 200 switch (op) { 201 /* 202 * Detach. Cleans up the target process, reparent it if possible 203 * and set it running once more. 204 */ 205 case PROCFS_CTL_DETACH: 206 /* if not being traced, then this is a painless no-op */ 207 if ((p->p_flag & P_TRACED) == 0) 208 return (0); 209 210 /* not being traced any more */ 211 p->p_flag &= ~P_TRACED; 212 213 /* remove pending SIGTRAP, else the process will die */ 214 lwp_delsig(lp, SIGTRAP); 215 216 /* give process back to original parent */ 217 if (p->p_oppid != p->p_pptr->p_pid) { 218 struct proc *pp; 219 220 pp = pfind(p->p_oppid); 221 if (pp) { 222 proc_reparent(p, pp); 223 PRELE(pp); 224 } 225 } 226 227 p->p_oppid = 0; 228 p->p_flag &= ~P_WAITED; /* XXX ? */ 229 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 230 231 break; 232 233 /* 234 * Step. Let the target process execute a single instruction. 235 */ 236 case PROCFS_CTL_STEP: 237 LWPHOLD(lp); 238 error = procfs_sstep(lp); 239 LWPRELE(lp); 240 if (error) 241 return (error); 242 break; 243 244 /* 245 * Run. Let the target process continue running until a breakpoint 246 * or some other trap. 247 */ 248 case PROCFS_CTL_RUN: 249 break; 250 251 /* 252 * Wait for the target process to stop. 253 * If the target is not being traced then just wait 254 * to enter 255 */ 256 case PROCFS_CTL_WAIT: 257 error = 0; 258 if (p->p_flag & P_TRACED) { 259 while (error == 0 && 260 p->p_stat != SSTOP && 261 (p->p_flag & P_TRACED) && 262 (p->p_pptr == curp)) { 263 error = tsleep((caddr_t) p, 264 PCATCH, "procfsx", 0); 265 } 266 if (error == 0 && !TRACE_WAIT_P(curp, p)) 267 error = EBUSY; 268 } else { 269 while (error == 0 && p->p_stat != SSTOP) { 270 error = tsleep((caddr_t) p, 271 PCATCH, "procfs", 0); 272 } 273 } 274 return (error); 275 276 default: 277 panic("procfs_control"); 278 } 279 280 /* 281 * If the process is in a stopped state, make it runnable again. 282 * Do not set LWP_BREAKTSLEEP - that is, do not break a tsleep that 283 * might be in progress. 284 */ 285 if (p->p_stat == SSTOP) 286 proc_unstop(p); 287 return (0); 288 } 289 290 int 291 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 292 struct uio *uio) 293 { 294 struct proc *p = lp->lwp_proc; 295 int xlen; 296 int error; 297 char msg[PROCFS_CTLLEN+1]; 298 vfs_namemap_t *nm; 299 300 ASSERT_LWKT_TOKEN_HELD(&p->p_token); 301 ASSERT_LWKT_TOKEN_HELD(&proc_token); 302 303 if (uio->uio_rw != UIO_WRITE) 304 return (EOPNOTSUPP); 305 306 xlen = PROCFS_CTLLEN; 307 error = vfs_getuserstr(uio, msg, &xlen); 308 if (error) 309 return (error); 310 311 /* 312 * Map signal names into signal generation 313 * or debug control. Unknown commands and/or signals 314 * return EOPNOTSUPP. 315 * 316 * Sending a signal while the process is being debugged 317 * also has the side effect of letting the target continue 318 * to run. There is no way to single-step a signal delivery. 319 */ 320 error = EOPNOTSUPP; 321 322 nm = vfs_findname(ctlnames, msg, xlen); 323 if (nm) { 324 error = procfs_control(curp, lp, nm->nm_val); 325 } else { 326 nm = vfs_findname(signames, msg, xlen); 327 if (nm) { 328 if (TRACE_WAIT_P(curp, p)) { 329 p->p_xstat = nm->nm_val; 330 #ifdef FIX_SSTEP 331 FIX_SSTEP(lp); 332 #endif 333 /* 334 * Make the process runnable but do not 335 * break its tsleep. 336 */ 337 proc_unstop(p); 338 } else { 339 ksignal(p, nm->nm_val); 340 } 341 error = 0; 342 } 343 } 344 345 return (error); 346 } 347