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