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 1.12 2007/02/19 01:14:24 corecode Exp $ 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/vnode.h> 48 #include <sys/ptrace.h> 49 #include <sys/signalvar.h> 50 #include <vfs/procfs/procfs.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_flag & 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 /* Can't trace a process that's currently exec'ing. */ 113 if ((p->p_flag & P_INEXEC) != 0) 114 return EAGAIN; 115 /* 116 * Authorization check: rely on normal debugging protection, except 117 * allow processes to disengage debugging on a process onto which 118 * they have previously attached, but no longer have permission to 119 * debug. 120 */ 121 if (op != PROCFS_CTL_DETACH) { 122 if (securelevel > 0 && p->p_pid == 1) 123 return (EPERM); 124 125 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 126 return (EPERM); 127 } 128 129 /* 130 * Attach - attaches the target process for debugging 131 * by the calling process. 132 */ 133 if (op == PROCFS_CTL_ATTACH) { 134 /* check whether already being traced */ 135 if (p->p_flag & P_TRACED) 136 return (EBUSY); 137 138 /* can't trace yourself! */ 139 if (p->p_pid == curp->p_pid) 140 return (EINVAL); 141 142 /* 143 * Go ahead and set the trace flag. 144 * Save the old parent (it's reset in 145 * _DETACH, and also in kern_exit.c:wait4() 146 * Reparent the process so that the tracing 147 * proc gets to see all the action. 148 * Stop the target. 149 */ 150 p->p_flag |= P_TRACED; 151 faultin(p); 152 p->p_xstat = 0; /* XXX ? */ 153 if (p->p_pptr != curp) { 154 p->p_oppid = p->p_pptr->p_pid; 155 proc_reparent(p, curp); 156 } 157 ksignal(p, SIGSTOP); 158 return (0); 159 } 160 161 /* 162 * Target process must be stopped, owned by (curp) and 163 * be set up for tracing (P_TRACED flag set). 164 * Allow DETACH to take place at any time for sanity. 165 * Allow WAIT any time, of course. 166 */ 167 switch (op) { 168 case PROCFS_CTL_DETACH: 169 case PROCFS_CTL_WAIT: 170 break; 171 172 default: 173 if (!TRACE_WAIT_P(curp, p)) 174 return (EBUSY); 175 } 176 177 178 #ifdef FIX_SSTEP 179 /* 180 * do single-step fixup if needed 181 */ 182 FIX_SSTEP(lp); 183 #endif 184 185 /* 186 * Don't deliver any signal by default. 187 * To continue with a signal, just send 188 * the signal name to the ctl file 189 */ 190 p->p_xstat = 0; 191 192 switch (op) { 193 /* 194 * Detach. Cleans up the target process, reparent it if possible 195 * and set it running once more. 196 */ 197 case PROCFS_CTL_DETACH: 198 /* if not being traced, then this is a painless no-op */ 199 if ((p->p_flag & P_TRACED) == 0) 200 return (0); 201 202 /* not being traced any more */ 203 p->p_flag &= ~P_TRACED; 204 205 /* remove pending SIGTRAP, else the process will die */ 206 SIGDELSET(p->p_siglist, SIGTRAP); 207 SIGDELSET(lp->lwp_siglist, SIGTRAP); 208 209 /* give process back to original parent */ 210 if (p->p_oppid != p->p_pptr->p_pid) { 211 struct proc *pp; 212 213 pp = pfind(p->p_oppid); 214 if (pp) 215 proc_reparent(p, pp); 216 } 217 218 p->p_oppid = 0; 219 p->p_flag &= ~P_WAITED; /* XXX ? */ 220 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 221 222 break; 223 224 /* 225 * Step. Let the target process execute a single instruction. 226 */ 227 case PROCFS_CTL_STEP: 228 LWPHOLD(lp); 229 error = procfs_sstep(lp); 230 LWPRELE(lp); 231 if (error) 232 return (error); 233 break; 234 235 /* 236 * Run. Let the target process continue running until a breakpoint 237 * or some other trap. 238 */ 239 case PROCFS_CTL_RUN: 240 break; 241 242 /* 243 * Wait for the target process to stop. 244 * If the target is not being traced then just wait 245 * to enter 246 */ 247 case PROCFS_CTL_WAIT: 248 error = 0; 249 if (p->p_flag & P_TRACED) { 250 while (error == 0 && 251 p->p_stat != SSTOP && 252 (p->p_flag & P_TRACED) && 253 (p->p_pptr == curp)) { 254 error = tsleep((caddr_t) p, 255 PCATCH, "procfsx", 0); 256 } 257 if (error == 0 && !TRACE_WAIT_P(curp, p)) 258 error = EBUSY; 259 } else { 260 while (error == 0 && p->p_stat != SSTOP) { 261 error = tsleep((caddr_t) p, 262 PCATCH, "procfs", 0); 263 } 264 } 265 return (error); 266 267 default: 268 panic("procfs_control"); 269 } 270 271 /* 272 * If the process is in a stopped state, make it runnable again. 273 * Do not set LWP_BREAKTSLEEP - that is, do not break a tsleep that 274 * might be in progress. 275 */ 276 if (p->p_stat == SSTOP) 277 proc_unstop(p); 278 return (0); 279 } 280 281 int 282 procfs_doctl(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 283 struct uio *uio) 284 { 285 struct proc *p = lp->lwp_proc; 286 int xlen; 287 int error; 288 char msg[PROCFS_CTLLEN+1]; 289 vfs_namemap_t *nm; 290 291 if (uio->uio_rw != UIO_WRITE) 292 return (EOPNOTSUPP); 293 294 xlen = PROCFS_CTLLEN; 295 error = vfs_getuserstr(uio, msg, &xlen); 296 if (error) 297 return (error); 298 299 /* 300 * Map signal names into signal generation 301 * or debug control. Unknown commands and/or signals 302 * return EOPNOTSUPP. 303 * 304 * Sending a signal while the process is being debugged 305 * also has the side effect of letting the target continue 306 * to run. There is no way to single-step a signal delivery. 307 */ 308 error = EOPNOTSUPP; 309 310 nm = vfs_findname(ctlnames, msg, xlen); 311 if (nm) { 312 error = procfs_control(curp, lp, nm->nm_val); 313 } else { 314 nm = vfs_findname(signames, msg, xlen); 315 if (nm) { 316 if (TRACE_WAIT_P(curp, p)) { 317 p->p_xstat = nm->nm_val; 318 #ifdef FIX_SSTEP 319 FIX_SSTEP(lp); 320 #endif 321 /* 322 * Make the process runnable but do not 323 * break its tsleep. 324 */ 325 proc_unstop(p); 326 } else { 327 ksignal(p, nm->nm_val); 328 } 329 error = 0; 330 } 331 } 332 333 return (error); 334 } 335