1 /*- 2 * Copyright (c) 2006 Roman Divacky 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_compat.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/imgact.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/malloc.h> 40 #include <sys/mutex.h> 41 #include <sys/sx.h> 42 #include <sys/proc.h> 43 #include <sys/syscallsubr.h> 44 #include <sys/sysent.h> 45 #include <sys/sysproto.h> 46 #include <sys/unistd.h> 47 48 #ifdef COMPAT_LINUX32 49 #include <machine/../linux32/linux.h> 50 #include <machine/../linux32/linux32_proto.h> 51 #else 52 #include <machine/../linux/linux.h> 53 #include <machine/../linux/linux_proto.h> 54 #endif 55 56 #include <compat/linux/linux_emul.h> 57 #include <compat/linux/linux_futex.h> 58 59 struct sx emul_shared_lock; 60 struct mtx emul_lock; 61 62 /* this returns locked reference to the emuldata entry (if found) */ 63 struct linux_emuldata * 64 em_find(struct proc *p, int locked) 65 { 66 struct linux_emuldata *em; 67 68 if (locked == EMUL_DOLOCK) 69 EMUL_LOCK(&emul_lock); 70 71 em = p->p_emuldata; 72 73 if (em == NULL && locked == EMUL_DOLOCK) 74 EMUL_UNLOCK(&emul_lock); 75 76 return (em); 77 } 78 79 int 80 linux_proc_init(struct thread *td, pid_t child, int flags) 81 { 82 struct linux_emuldata *em, *p_em; 83 struct proc *p; 84 85 if (child != 0) { 86 /* non-exec call */ 87 em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO); 88 em->pid = child; 89 em->pdeath_signal = 0; 90 em->flags = 0; 91 em->robust_futexes = NULL; 92 if (flags & LINUX_CLONE_THREAD) { 93 /* handled later in the code */ 94 } else { 95 struct linux_emuldata_shared *s; 96 97 s = malloc(sizeof *s, M_LINUX, M_WAITOK | M_ZERO); 98 s->refs = 1; 99 s->group_pid = child; 100 101 LIST_INIT(&s->threads); 102 em->shared = s; 103 } 104 } else { 105 /* lookup the old one */ 106 em = em_find(td->td_proc, EMUL_DOLOCK); 107 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n")); 108 } 109 110 em->child_clear_tid = NULL; 111 em->child_set_tid = NULL; 112 113 /* 114 * allocate the shared struct only in clone()/fork cases in the case 115 * of clone() td = calling proc and child = pid of the newly created 116 * proc 117 */ 118 if (child != 0) { 119 if (flags & LINUX_CLONE_THREAD) { 120 /* lookup the parent */ 121 /* 122 * we dont have to lock the p_em because 123 * its waiting for us in linux_clone so 124 * there is no chance of it changing the 125 * p_em->shared address 126 */ 127 p_em = em_find(td->td_proc, EMUL_DONTLOCK); 128 KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_THREAD\n")); 129 em->shared = p_em->shared; 130 EMUL_SHARED_WLOCK(&emul_shared_lock); 131 em->shared->refs++; 132 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 133 } else { 134 /* 135 * handled earlier to avoid malloc(M_WAITOK) with 136 * rwlock held 137 */ 138 } 139 } 140 if (child != 0) { 141 EMUL_SHARED_WLOCK(&emul_shared_lock); 142 LIST_INSERT_HEAD(&em->shared->threads, em, threads); 143 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 144 145 p = pfind(child); 146 KASSERT(p != NULL, ("process not found in proc_init\n")); 147 p->p_emuldata = em; 148 PROC_UNLOCK(p); 149 } else 150 EMUL_UNLOCK(&emul_lock); 151 152 return (0); 153 } 154 155 void 156 linux_proc_exit(void *arg __unused, struct proc *p) 157 { 158 struct linux_emuldata *em; 159 int error, shared_flags, shared_xstat; 160 struct thread *td = FIRST_THREAD_IN_PROC(p); 161 int *child_clear_tid; 162 struct proc *q, *nq; 163 164 if (__predict_true(p->p_sysent != &elf_linux_sysvec)) 165 return; 166 167 release_futexes(p); 168 169 /* find the emuldata */ 170 em = em_find(p, EMUL_DOLOCK); 171 172 KASSERT(em != NULL, ("proc_exit: emuldata not found.\n")); 173 174 /* reparent all procs that are not a thread leader to initproc */ 175 if (em->shared->group_pid != p->p_pid) { 176 child_clear_tid = em->child_clear_tid; 177 EMUL_UNLOCK(&emul_lock); 178 sx_xlock(&proctree_lock); 179 wakeup(initproc); 180 PROC_LOCK(p); 181 proc_reparent(p, initproc); 182 p->p_sigparent = SIGCHLD; 183 PROC_UNLOCK(p); 184 sx_xunlock(&proctree_lock); 185 } else { 186 child_clear_tid = em->child_clear_tid; 187 EMUL_UNLOCK(&emul_lock); 188 } 189 190 EMUL_SHARED_WLOCK(&emul_shared_lock); 191 shared_flags = em->shared->flags; 192 shared_xstat = em->shared->xstat; 193 LIST_REMOVE(em, threads); 194 195 em->shared->refs--; 196 if (em->shared->refs == 0) { 197 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 198 free(em->shared, M_LINUX); 199 } else 200 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 201 202 if ((shared_flags & EMUL_SHARED_HASXSTAT) != 0) 203 p->p_xstat = shared_xstat; 204 205 if (child_clear_tid != NULL) { 206 struct linux_sys_futex_args cup; 207 int null = 0; 208 209 error = copyout(&null, child_clear_tid, sizeof(null)); 210 if (error) { 211 free(em, M_LINUX); 212 return; 213 } 214 215 /* futexes stuff */ 216 cup.uaddr = child_clear_tid; 217 cup.op = LINUX_FUTEX_WAKE; 218 cup.val = 0x7fffffff; /* Awake everyone */ 219 cup.timeout = NULL; 220 cup.uaddr2 = NULL; 221 cup.val3 = 0; 222 error = linux_sys_futex(FIRST_THREAD_IN_PROC(p), &cup); 223 /* 224 * this cannot happen at the moment and if this happens it 225 * probably means there is a user space bug 226 */ 227 if (error) 228 printf(LMSG("futex stuff in proc_exit failed.\n")); 229 } 230 231 /* clean the stuff up */ 232 free(em, M_LINUX); 233 234 /* this is a little weird but rewritten from exit1() */ 235 sx_xlock(&proctree_lock); 236 q = LIST_FIRST(&p->p_children); 237 for (; q != NULL; q = nq) { 238 nq = LIST_NEXT(q, p_sibling); 239 if (q->p_flag & P_WEXIT) 240 continue; 241 if (__predict_false(q->p_sysent != &elf_linux_sysvec)) 242 continue; 243 em = em_find(q, EMUL_DOLOCK); 244 KASSERT(em != NULL, ("linux_reparent: emuldata not found: %i\n", q->p_pid)); 245 PROC_LOCK(q); 246 if ((q->p_flag & P_WEXIT) == 0 && em->pdeath_signal != 0) { 247 kern_psignal(q, em->pdeath_signal); 248 } 249 PROC_UNLOCK(q); 250 EMUL_UNLOCK(&emul_lock); 251 } 252 sx_xunlock(&proctree_lock); 253 } 254 255 /* 256 * This is used in a case of transition from FreeBSD binary execing to linux binary 257 * in this case we create linux emuldata proc entry with the pid of the currently running 258 * process. 259 */ 260 void 261 linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp) 262 { 263 if (__predict_false(imgp->sysent == &elf_linux_sysvec 264 && p->p_sysent != &elf_linux_sysvec)) 265 linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0); 266 if (__predict_false((p->p_sysent->sv_flags & SV_ABI_MASK) == 267 SV_ABI_LINUX)) 268 /* Kill threads regardless of imgp->sysent value */ 269 linux_kill_threads(FIRST_THREAD_IN_PROC(p), SIGKILL); 270 if (__predict_false(imgp->sysent != &elf_linux_sysvec 271 && p->p_sysent == &elf_linux_sysvec)) { 272 struct linux_emuldata *em; 273 274 /* 275 * XXX:There's a race because here we assign p->p_emuldata NULL 276 * but the process is still counted as linux one for a short 277 * time so some other process might reference it and try to 278 * access its p->p_emuldata and panicing on a NULL reference. 279 */ 280 em = em_find(p, EMUL_DONTLOCK); 281 282 KASSERT(em != NULL, ("proc_exec: emuldata not found.\n")); 283 284 EMUL_SHARED_WLOCK(&emul_shared_lock); 285 LIST_REMOVE(em, threads); 286 287 PROC_LOCK(p); 288 p->p_emuldata = NULL; 289 PROC_UNLOCK(p); 290 291 em->shared->refs--; 292 if (em->shared->refs == 0) { 293 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 294 free(em->shared, M_LINUX); 295 } else 296 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 297 298 free(em, M_LINUX); 299 } 300 } 301 302 void 303 linux_schedtail(struct thread *td) 304 { 305 struct linux_emuldata *em; 306 struct proc *p; 307 int error = 0; 308 int *child_set_tid; 309 310 p = td->td_proc; 311 312 /* find the emuldata */ 313 em = em_find(p, EMUL_DOLOCK); 314 315 KASSERT(em != NULL, ("linux_schedtail: emuldata not found.\n")); 316 child_set_tid = em->child_set_tid; 317 EMUL_UNLOCK(&emul_lock); 318 319 if (child_set_tid != NULL) 320 error = copyout(&p->p_pid, (int *)child_set_tid, 321 sizeof(p->p_pid)); 322 323 return; 324 } 325 326 int 327 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args) 328 { 329 struct linux_emuldata *em; 330 331 #ifdef DEBUG 332 if (ldebug(set_tid_address)) 333 printf(ARGS(set_tid_address, "%p"), args->tidptr); 334 #endif 335 336 /* find the emuldata */ 337 em = em_find(td->td_proc, EMUL_DOLOCK); 338 339 KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n")); 340 341 em->child_clear_tid = args->tidptr; 342 td->td_retval[0] = td->td_proc->p_pid; 343 344 EMUL_UNLOCK(&emul_lock); 345 return 0; 346 } 347 348 void 349 linux_kill_threads(struct thread *td, int sig) 350 { 351 struct linux_emuldata *em, *td_em, *tmp_em; 352 struct proc *sp; 353 354 td_em = em_find(td->td_proc, EMUL_DONTLOCK); 355 356 KASSERT(td_em != NULL, ("linux_kill_threads: emuldata not found.\n")); 357 358 EMUL_SHARED_RLOCK(&emul_shared_lock); 359 LIST_FOREACH_SAFE(em, &td_em->shared->threads, threads, tmp_em) { 360 if (em->pid == td_em->pid) 361 continue; 362 363 sp = pfind(em->pid); 364 if ((sp->p_flag & P_WEXIT) == 0) 365 kern_psignal(sp, sig); 366 PROC_UNLOCK(sp); 367 #ifdef DEBUG 368 printf(LMSG("linux_kill_threads: kill PID %d\n"), em->pid); 369 #endif 370 } 371 EMUL_SHARED_RUNLOCK(&emul_shared_lock); 372 } 373