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 <sys/signal2.h> 52 #include <vfs/procfs/procfs.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_flag & 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(&proc_token); 115 116 /* Can't trace a process that's currently exec'ing. */ 117 if ((p->p_flag & 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_flag & 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_flag |= 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); 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_flag & P_TRACED) == 0) 204 return (0); 205 206 /* not being traced any more */ 207 p->p_flag &= ~P_TRACED; 208 209 /* remove pending SIGTRAP, else the process will die */ 210 lwp_delsig(lp, SIGTRAP); 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 = pfind(p->p_oppid); 217 if (pp) 218 proc_reparent(p, pp); 219 } 220 221 p->p_oppid = 0; 222 p->p_flag &= ~P_WAITED; /* XXX ? */ 223 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 224 225 break; 226 227 /* 228 * Step. Let the target process execute a single instruction. 229 */ 230 case PROCFS_CTL_STEP: 231 LWPHOLD(lp); 232 error = procfs_sstep(lp); 233 LWPRELE(lp); 234 if (error) 235 return (error); 236 break; 237 238 /* 239 * Run. Let the target process continue running until a breakpoint 240 * or some other trap. 241 */ 242 case PROCFS_CTL_RUN: 243 break; 244 245 /* 246 * Wait for the target process to stop. 247 * If the target is not being traced then just wait 248 * to enter 249 */ 250 case PROCFS_CTL_WAIT: 251 error = 0; 252 if (p->p_flag & P_TRACED) { 253 while (error == 0 && 254 p->p_stat != SSTOP && 255 (p->p_flag & P_TRACED) && 256 (p->p_pptr == curp)) { 257 error = tsleep((caddr_t) p, 258 PCATCH, "procfsx", 0); 259 } 260 if (error == 0 && !TRACE_WAIT_P(curp, p)) 261 error = EBUSY; 262 } else { 263 while (error == 0 && p->p_stat != SSTOP) { 264 error = tsleep((caddr_t) p, 265 PCATCH, "procfs", 0); 266 } 267 } 268 return (error); 269 270 default: 271 panic("procfs_control"); 272 } 273 274 /* 275 * If the process is in a stopped state, make it runnable again. 276 * Do not set LWP_BREAKTSLEEP - that is, do not break a tsleep that 277 * might be in progress. 278 */ 279 if (p->p_stat == SSTOP) 280 proc_unstop(p); 281 return (0); 282 } 283 284 int 285 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 286 struct uio *uio) 287 { 288 struct proc *p = lp->lwp_proc; 289 int xlen; 290 int error; 291 char msg[PROCFS_CTLLEN+1]; 292 vfs_namemap_t *nm; 293 294 ASSERT_LWKT_TOKEN_HELD(&proc_token); 295 296 if (uio->uio_rw != UIO_WRITE) 297 return (EOPNOTSUPP); 298 299 xlen = PROCFS_CTLLEN; 300 error = vfs_getuserstr(uio, msg, &xlen); 301 if (error) 302 return (error); 303 304 /* 305 * Map signal names into signal generation 306 * or debug control. Unknown commands and/or signals 307 * return EOPNOTSUPP. 308 * 309 * Sending a signal while the process is being debugged 310 * also has the side effect of letting the target continue 311 * to run. There is no way to single-step a signal delivery. 312 */ 313 error = EOPNOTSUPP; 314 315 nm = vfs_findname(ctlnames, msg, xlen); 316 if (nm) { 317 error = procfs_control(curp, lp, nm->nm_val); 318 } else { 319 nm = vfs_findname(signames, msg, xlen); 320 if (nm) { 321 if (TRACE_WAIT_P(curp, p)) { 322 p->p_xstat = nm->nm_val; 323 #ifdef FIX_SSTEP 324 FIX_SSTEP(lp); 325 #endif 326 /* 327 * Make the process runnable but do not 328 * break its tsleep. 329 */ 330 proc_unstop(p); 331 } else { 332 ksignal(p, nm->nm_val); 333 } 334 error = 0; 335 } 336 } 337 338 return (error); 339 } 340