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 1.8 2005/11/14 18:50:13 dillon 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(p) 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_flag & P_STOPPED) && \ 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 proc *p, int op); 105 106 static int 107 procfs_control(struct proc *curp, struct proc *p, int op) 108 { 109 int error; 110 111 /* Can't trace a process that's currently exec'ing. */ 112 if ((p->p_flag & P_INEXEC) != 0) 113 return EAGAIN; 114 /* 115 * Authorization check: rely on normal debugging protection, except 116 * allow processes to disengage debugging on a process onto which 117 * they have previously attached, but no longer have permission to 118 * debug. 119 */ 120 if (op != PROCFS_CTL_DETACH) { 121 if (securelevel > 0 && p->p_pid == 1) 122 return (EPERM); 123 124 if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) 125 return (EPERM); 126 } 127 128 /* 129 * Attach - attaches the target process for debugging 130 * by the calling process. 131 */ 132 if (op == PROCFS_CTL_ATTACH) { 133 /* check whether already being traced */ 134 if (p->p_flag & P_TRACED) 135 return (EBUSY); 136 137 /* can't trace yourself! */ 138 if (p->p_pid == curp->p_pid) 139 return (EINVAL); 140 141 /* 142 * Go ahead and set the trace flag. 143 * Save the old parent (it's reset in 144 * _DETACH, and also in kern_exit.c:wait4() 145 * Reparent the process so that the tracing 146 * proc gets to see all the action. 147 * Stop the target. 148 */ 149 p->p_flag |= P_TRACED; 150 faultin(p); 151 p->p_xstat = 0; /* XXX ? */ 152 if (p->p_pptr != curp) { 153 p->p_oppid = p->p_pptr->p_pid; 154 proc_reparent(p, curp); 155 } 156 psignal(p, SIGSTOP); 157 return (0); 158 } 159 160 /* 161 * Target process must be stopped, owned by (curp) and 162 * be set up for tracing (P_TRACED flag set). 163 * Allow DETACH to take place at any time for sanity. 164 * Allow WAIT any time, of course. 165 */ 166 switch (op) { 167 case PROCFS_CTL_DETACH: 168 case PROCFS_CTL_WAIT: 169 break; 170 171 default: 172 if (!TRACE_WAIT_P(curp, p)) 173 return (EBUSY); 174 } 175 176 177 #ifdef FIX_SSTEP 178 /* 179 * do single-step fixup if needed 180 */ 181 FIX_SSTEP(p); 182 #endif 183 184 /* 185 * Don't deliver any signal by default. 186 * To continue with a signal, just send 187 * the signal name to the ctl file 188 */ 189 p->p_xstat = 0; 190 191 switch (op) { 192 /* 193 * Detach. Cleans up the target process, reparent it if possible 194 * and set it running once more. 195 */ 196 case PROCFS_CTL_DETACH: 197 /* if not being traced, then this is a painless no-op */ 198 if ((p->p_flag & P_TRACED) == 0) 199 return (0); 200 201 /* not being traced any more */ 202 p->p_flag &= ~P_TRACED; 203 204 /* remove pending SIGTRAP, else the process will die */ 205 SIGDELSET(p->p_siglist, SIGTRAP); 206 207 /* give process back to original parent */ 208 if (p->p_oppid != p->p_pptr->p_pid) { 209 struct proc *pp; 210 211 pp = pfind(p->p_oppid); 212 if (pp) 213 proc_reparent(p, pp); 214 } 215 216 p->p_oppid = 0; 217 p->p_flag &= ~P_WAITED; /* XXX ? */ 218 wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */ 219 220 break; 221 222 /* 223 * Step. Let the target process execute a single instruction. 224 */ 225 case PROCFS_CTL_STEP: 226 PHOLD(p); 227 error = procfs_sstep(p); 228 PRELE(p); 229 if (error) 230 return (error); 231 break; 232 233 /* 234 * Run. Let the target process continue running until a breakpoint 235 * or some other trap. 236 */ 237 case PROCFS_CTL_RUN: 238 break; 239 240 /* 241 * Wait for the target process to stop. 242 * If the target is not being traced then just wait 243 * to enter 244 */ 245 case PROCFS_CTL_WAIT: 246 error = 0; 247 if (p->p_flag & P_TRACED) { 248 while (error == 0 && 249 (p->p_flag & P_STOPPED) == 0 && 250 (p->p_flag & P_TRACED) && 251 (p->p_pptr == curp)) { 252 error = tsleep((caddr_t) p, 253 PCATCH, "procfsx", 0); 254 } 255 if (error == 0 && !TRACE_WAIT_P(curp, p)) 256 error = EBUSY; 257 } else { 258 while (error == 0 && (p->p_flag & P_STOPPED) == 0) { 259 error = tsleep((caddr_t) p, 260 PCATCH, "procfs", 0); 261 } 262 } 263 return (error); 264 265 default: 266 panic("procfs_control"); 267 } 268 269 /* 270 * If the process is in a stopped state, make it runnable again. 271 * Do not set P_BREAKTSLEEP - that is, do not break a tsleep that 272 * might be in progress. 273 */ 274 if (p->p_flag & P_STOPPED) 275 setrunnable(p); 276 return (0); 277 } 278 279 int 280 procfs_doctl(struct proc *curp, struct proc *p, struct pfsnode *pfs, 281 struct uio *uio) 282 { 283 int xlen; 284 int error; 285 char msg[PROCFS_CTLLEN+1]; 286 vfs_namemap_t *nm; 287 288 if (uio->uio_rw != UIO_WRITE) 289 return (EOPNOTSUPP); 290 291 xlen = PROCFS_CTLLEN; 292 error = vfs_getuserstr(uio, msg, &xlen); 293 if (error) 294 return (error); 295 296 /* 297 * Map signal names into signal generation 298 * or debug control. Unknown commands and/or signals 299 * return EOPNOTSUPP. 300 * 301 * Sending a signal while the process is being debugged 302 * also has the side effect of letting the target continue 303 * to run. There is no way to single-step a signal delivery. 304 */ 305 error = EOPNOTSUPP; 306 307 nm = vfs_findname(ctlnames, msg, xlen); 308 if (nm) { 309 error = procfs_control(curp, p, nm->nm_val); 310 } else { 311 nm = vfs_findname(signames, msg, xlen); 312 if (nm) { 313 if (TRACE_WAIT_P(curp, p)) { 314 p->p_xstat = nm->nm_val; 315 #ifdef FIX_SSTEP 316 FIX_SSTEP(p); 317 #endif 318 /* 319 * Make the process runnable but do not 320 * break its tsleep. 321 */ 322 setrunnable(p); 323 } else { 324 psignal(p, nm->nm_val); 325 } 326 error = 0; 327 } 328 } 329 330 return (error); 331 } 332