1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1994-1996 Søren Schmidt 5 * Copyright (c) 2006 Roman Divacky 6 * Copyright (c) 2013 Dmitry Chagin 7 * All rights reserved. 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 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/fcntl.h> 37 #include <sys/imgact.h> 38 #include <sys/kernel.h> 39 #include <sys/ktr.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/mutex.h> 43 #include <sys/sx.h> 44 #include <sys/proc.h> 45 #include <sys/resourcevar.h> 46 #include <sys/syscallsubr.h> 47 #include <sys/sysent.h> 48 49 #include <compat/linux/linux_emul.h> 50 #include <compat/linux/linux_mib.h> 51 #include <compat/linux/linux_misc.h> 52 #include <compat/linux/linux_persona.h> 53 #include <compat/linux/linux_util.h> 54 55 #if BYTE_ORDER == LITTLE_ENDIAN 56 #define SHELLMAGIC 0x2123 /* #! */ 57 #else 58 #define SHELLMAGIC 0x2321 59 #endif 60 61 /* 62 * This returns reference to the thread emuldata entry (if found) 63 * 64 * Hold PROC_LOCK when referencing emuldata from other threads. 65 */ 66 struct linux_emuldata * 67 em_find(struct thread *td) 68 { 69 struct linux_emuldata *em; 70 71 em = td->td_emuldata; 72 73 return (em); 74 } 75 76 /* 77 * This returns reference to the proc pemuldata entry (if found) 78 * 79 * Hold PROC_LOCK when referencing proc pemuldata from other threads. 80 * Hold LINUX_PEM_LOCK wher referencing pemuldata members. 81 */ 82 struct linux_pemuldata * 83 pem_find(struct proc *p) 84 { 85 struct linux_pemuldata *pem; 86 87 pem = p->p_emuldata; 88 89 return (pem); 90 } 91 92 /* 93 * Linux apps generally expect the soft open file limit to be set 94 * to 1024, often iterating over all the file descriptors up to that 95 * limit instead of using closefrom(2). Give them what they want, 96 * unless there already is a resource limit in place. 97 */ 98 static void 99 linux_set_default_openfiles(struct thread *td, struct proc *p) 100 { 101 struct rlimit rlim; 102 int error; 103 104 if (linux_default_openfiles < 0) 105 return; 106 107 PROC_LOCK(p); 108 lim_rlimit_proc(p, RLIMIT_NOFILE, &rlim); 109 PROC_UNLOCK(p); 110 if (rlim.rlim_cur != rlim.rlim_max || 111 rlim.rlim_cur <= linux_default_openfiles) 112 return; 113 rlim.rlim_cur = linux_default_openfiles; 114 error = kern_proc_setrlimit(td, p, RLIMIT_NOFILE, &rlim); 115 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 116 } 117 118 void 119 linux_proc_init(struct thread *td, struct thread *newtd, int flags) 120 { 121 struct linux_emuldata *em; 122 struct linux_pemuldata *pem; 123 struct epoll_emuldata *emd; 124 struct proc *p; 125 126 if (newtd != NULL) { 127 p = newtd->td_proc; 128 129 /* non-exec call */ 130 em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO); 131 if (flags & LINUX_CLONE_THREAD) { 132 LINUX_CTR1(proc_init, "thread newtd(%d)", 133 newtd->td_tid); 134 135 em->em_tid = newtd->td_tid; 136 } else { 137 LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid); 138 139 em->em_tid = p->p_pid; 140 141 pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO); 142 sx_init(&pem->pem_sx, "lpemlk"); 143 p->p_emuldata = pem; 144 } 145 newtd->td_emuldata = em; 146 147 linux_set_default_openfiles(td, p); 148 } else { 149 p = td->td_proc; 150 151 /* exec */ 152 LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid); 153 154 /* lookup the old one */ 155 em = em_find(td); 156 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n")); 157 158 em->em_tid = p->p_pid; 159 em->flags = 0; 160 em->robust_futexes = NULL; 161 em->child_clear_tid = NULL; 162 em->child_set_tid = NULL; 163 164 /* epoll should be destroyed in a case of exec. */ 165 pem = pem_find(p); 166 KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n")); 167 pem->persona = 0; 168 if (pem->epoll != NULL) { 169 emd = pem->epoll; 170 pem->epoll = NULL; 171 free(emd, M_EPOLL); 172 } 173 } 174 175 } 176 177 void 178 linux_proc_exit(void *arg __unused, struct proc *p) 179 { 180 struct linux_pemuldata *pem; 181 struct epoll_emuldata *emd; 182 struct thread *td = curthread; 183 184 if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX)) 185 return; 186 187 LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p", 188 td->td_tid, p->p_pid, p); 189 190 pem = pem_find(p); 191 if (pem == NULL) 192 return; 193 (p->p_sysent->sv_thread_detach)(td); 194 195 p->p_emuldata = NULL; 196 197 if (pem->epoll != NULL) { 198 emd = pem->epoll; 199 pem->epoll = NULL; 200 free(emd, M_EPOLL); 201 } 202 203 sx_destroy(&pem->pem_sx); 204 free(pem, M_LINUX); 205 } 206 207 /* 208 * If a Linux binary is exec'ing something, try this image activator 209 * first. We override standard shell script execution in order to 210 * be able to modify the interpreter path. We only do this if a Linux 211 * binary is doing the exec, so we do not create an EXEC module for it. 212 */ 213 int 214 linux_exec_imgact_try(struct image_params *imgp) 215 { 216 const char *head = (const char *)imgp->image_header; 217 char *rpath; 218 int error = -1; 219 220 /* 221 * The interpreter for shell scripts run from a Linux binary needs 222 * to be located in /compat/linux if possible in order to recursively 223 * maintain Linux path emulation. 224 */ 225 if (((const short *)head)[0] == SHELLMAGIC) { 226 /* 227 * Run our normal shell image activator. If it succeeds attempt 228 * to use the alternate path for the interpreter. If an 229 * alternate path is found, use our stringspace to store it. 230 */ 231 if ((error = exec_shell_imgact(imgp)) == 0) { 232 linux_emul_convpath(FIRST_THREAD_IN_PROC(imgp->proc), 233 imgp->interpreter_name, UIO_SYSSPACE, &rpath, 0, 234 AT_FDCWD); 235 if (rpath != NULL) 236 imgp->args->fname_buf = 237 imgp->interpreter_name = rpath; 238 } 239 } 240 return (error); 241 } 242 243 int 244 linux_common_execve(struct thread *td, struct image_args *eargs) 245 { 246 struct linux_pemuldata *pem; 247 struct epoll_emuldata *emd; 248 struct vmspace *oldvmspace; 249 struct linux_emuldata *em; 250 struct proc *p; 251 int error; 252 253 p = td->td_proc; 254 255 error = pre_execve(td, &oldvmspace); 256 if (error != 0) 257 return (error); 258 259 error = kern_execve(td, eargs, NULL); 260 post_execve(td, error, oldvmspace); 261 if (error != EJUSTRETURN) 262 return (error); 263 264 /* 265 * In a case of transition from Linux binary execing to 266 * FreeBSD binary we destroy Linux emuldata thread & proc entries. 267 */ 268 if (SV_CURPROC_ABI() != SV_ABI_LINUX) { 269 PROC_LOCK(p); 270 em = em_find(td); 271 KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n")); 272 td->td_emuldata = NULL; 273 274 pem = pem_find(p); 275 KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n")); 276 p->p_emuldata = NULL; 277 PROC_UNLOCK(p); 278 279 if (pem->epoll != NULL) { 280 emd = pem->epoll; 281 pem->epoll = NULL; 282 free(emd, M_EPOLL); 283 } 284 285 free(em, M_TEMP); 286 free(pem, M_LINUX); 287 } 288 return (EJUSTRETURN); 289 } 290 291 void 292 linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp) 293 { 294 struct thread *td; 295 struct thread *othertd; 296 #if defined(__amd64__) 297 struct linux_pemuldata *pem; 298 #endif 299 300 td = curthread; 301 302 /* 303 * In a case of execing to Linux binary we create Linux 304 * emuldata thread entry. 305 */ 306 if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) == 307 SV_ABI_LINUX)) { 308 if (SV_PROC_ABI(p) == SV_ABI_LINUX) { 309 /* 310 * Process already was under Linuxolator 311 * before exec. Update emuldata to reflect 312 * single-threaded cleaned state after exec. 313 */ 314 linux_proc_init(td, NULL, 0); 315 } else { 316 /* 317 * We are switching the process to Linux emulator. 318 */ 319 linux_proc_init(td, td, 0); 320 321 /* 322 * Create a transient td_emuldata for all suspended 323 * threads, so that p->p_sysent->sv_thread_detach() == 324 * linux_thread_detach() can find expected but unused 325 * emuldata. 326 */ 327 FOREACH_THREAD_IN_PROC(td->td_proc, othertd) { 328 if (othertd != td) { 329 linux_proc_init(td, othertd, 330 LINUX_CLONE_THREAD); 331 } 332 } 333 } 334 #if defined(__amd64__) 335 /* 336 * An IA32 executable which has executable stack will have the 337 * READ_IMPLIES_EXEC personality flag set automatically. 338 */ 339 if (SV_PROC_FLAG(td->td_proc, SV_ILP32) && 340 imgp->stack_prot & VM_PROT_EXECUTE) { 341 pem = pem_find(p); 342 pem->persona |= LINUX_READ_IMPLIES_EXEC; 343 } 344 #endif 345 } 346 } 347 348 void 349 linux_thread_dtor(void *arg __unused, struct thread *td) 350 { 351 struct linux_emuldata *em; 352 353 em = em_find(td); 354 if (em == NULL) 355 return; 356 td->td_emuldata = NULL; 357 358 LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid); 359 360 free(em, M_TEMP); 361 } 362 363 void 364 linux_schedtail(struct thread *td) 365 { 366 struct linux_emuldata *em; 367 struct proc *p; 368 int error = 0; 369 int *child_set_tid; 370 371 p = td->td_proc; 372 373 em = em_find(td); 374 KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n")); 375 child_set_tid = em->child_set_tid; 376 377 if (child_set_tid != NULL) { 378 error = copyout(&em->em_tid, child_set_tid, 379 sizeof(em->em_tid)); 380 LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d", 381 td->td_tid, child_set_tid, em->em_tid, error); 382 } else 383 LINUX_CTR1(schedtail, "thread(%d)", em->em_tid); 384 } 385