1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1994-1996 Søren Schmidt 5 * Copyright (c) 2006 Roman Divacky 6 * All rights reserved. 7 * Copyright (c) 2013 Dmitry Chagin <dchagin@FreeBSD.org> 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/fcntl.h> 36 #include <sys/imgact.h> 37 #include <sys/ktr.h> 38 #include <sys/lock.h> 39 #include <sys/malloc.h> 40 #include <sys/mutex.h> 41 #include <sys/proc.h> 42 #include <sys/resourcevar.h> 43 #include <sys/sx.h> 44 #include <sys/syscallsubr.h> 45 #include <sys/sysent.h> 46 47 #include <compat/linux/linux_emul.h> 48 #include <compat/linux/linux_mib.h> 49 #include <compat/linux/linux_misc.h> 50 #include <compat/linux/linux_persona.h> 51 #include <compat/linux/linux_util.h> 52 53 #if BYTE_ORDER == LITTLE_ENDIAN 54 #define SHELLMAGIC 0x2123 /* #! */ 55 #else 56 #define SHELLMAGIC 0x2321 57 #endif 58 59 /* 60 * This returns reference to the thread emuldata entry (if found) 61 * 62 * Hold PROC_LOCK when referencing emuldata from other threads. 63 */ 64 struct linux_emuldata * 65 em_find(struct thread *td) 66 { 67 struct linux_emuldata *em; 68 69 em = td->td_emuldata; 70 71 return (em); 72 } 73 74 /* 75 * This returns reference to the proc pemuldata entry (if found) 76 * 77 * Hold PROC_LOCK when referencing proc pemuldata from other threads. 78 * Hold LINUX_PEM_LOCK wher referencing pemuldata members. 79 */ 80 struct linux_pemuldata * 81 pem_find(struct proc *p) 82 { 83 struct linux_pemuldata *pem; 84 85 pem = p->p_emuldata; 86 87 return (pem); 88 } 89 90 /* 91 * Linux apps generally expect the soft open file limit to be set 92 * to 1024, often iterating over all the file descriptors up to that 93 * limit instead of using closefrom(2). Give them what they want, 94 * unless there already is a resource limit in place. 95 */ 96 static void 97 linux_set_default_openfiles(struct thread *td, struct proc *p) 98 { 99 struct rlimit rlim; 100 int error __diagused; 101 102 if (linux_default_openfiles < 0) 103 return; 104 105 PROC_LOCK(p); 106 lim_rlimit_proc(p, RLIMIT_NOFILE, &rlim); 107 PROC_UNLOCK(p); 108 if (rlim.rlim_cur != rlim.rlim_max || 109 rlim.rlim_cur <= linux_default_openfiles) 110 return; 111 rlim.rlim_cur = linux_default_openfiles; 112 error = kern_proc_setrlimit(td, p, RLIMIT_NOFILE, &rlim); 113 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 114 } 115 116 /* 117 * The default stack size limit in Linux is 8MB. 118 */ 119 static void 120 linux_set_default_stacksize(struct thread *td, struct proc *p) 121 { 122 struct rlimit rlim; 123 int error __diagused; 124 125 if (linux_default_stacksize < 0) 126 return; 127 128 PROC_LOCK(p); 129 lim_rlimit_proc(p, RLIMIT_STACK, &rlim); 130 PROC_UNLOCK(p); 131 if (rlim.rlim_cur != rlim.rlim_max || 132 rlim.rlim_cur <= linux_default_stacksize) 133 return; 134 rlim.rlim_cur = linux_default_stacksize; 135 error = kern_proc_setrlimit(td, p, RLIMIT_STACK, &rlim); 136 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 137 } 138 139 void 140 linux_proc_init(struct thread *td, struct thread *newtd, bool init_thread) 141 { 142 struct linux_emuldata *em; 143 struct linux_pemuldata *pem; 144 struct proc *p; 145 146 if (newtd != NULL) { 147 p = newtd->td_proc; 148 149 /* non-exec call */ 150 em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO); 151 if (init_thread) { 152 LINUX_CTR1(proc_init, "thread newtd(%d)", 153 newtd->td_tid); 154 155 em->em_tid = newtd->td_tid; 156 } else { 157 LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid); 158 159 em->em_tid = p->p_pid; 160 161 pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO); 162 sx_init(&pem->pem_sx, "lpemlk"); 163 p->p_emuldata = pem; 164 } 165 newtd->td_emuldata = em; 166 167 linux_set_default_openfiles(td, p); 168 linux_set_default_stacksize(td, p); 169 } else { 170 p = td->td_proc; 171 172 /* exec */ 173 LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid); 174 175 /* lookup the old one */ 176 em = em_find(td); 177 KASSERT(em != NULL, ("proc_init: thread emuldata not found.\n")); 178 179 em->em_tid = p->p_pid; 180 em->flags = 0; 181 em->robust_futexes = NULL; 182 em->child_clear_tid = NULL; 183 em->child_set_tid = NULL; 184 185 pem = pem_find(p); 186 KASSERT(pem != NULL, ("proc_init: proc emuldata not found.\n")); 187 pem->persona = 0; 188 pem->oom_score_adj = 0; 189 } 190 } 191 192 void 193 linux_on_exit(struct proc *p) 194 { 195 struct linux_pemuldata *pem; 196 struct thread *td = curthread; 197 198 MPASS(SV_CURPROC_ABI() == SV_ABI_LINUX); 199 200 LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p", 201 td->td_tid, p->p_pid, p); 202 203 pem = pem_find(p); 204 if (pem == NULL) 205 return; 206 (p->p_sysent->sv_thread_detach)(td); 207 208 p->p_emuldata = NULL; 209 210 sx_destroy(&pem->pem_sx); 211 free(pem, M_LINUX); 212 } 213 214 /* 215 * If a Linux binary is exec'ing something, try this image activator 216 * first. We override standard shell script execution in order to 217 * be able to modify the interpreter path. We only do this if a Linux 218 * binary is doing the exec, so we do not create an EXEC module for it. 219 */ 220 int 221 linux_exec_imgact_try(struct image_params *imgp) 222 { 223 const char *head = (const char *)imgp->image_header; 224 char *rpath; 225 int error = -1; 226 227 /* 228 * The interpreter for shell scripts run from a Linux binary needs 229 * to be located in /compat/linux if possible in order to recursively 230 * maintain Linux path emulation. 231 */ 232 if (((const short *)head)[0] == SHELLMAGIC) { 233 /* 234 * Run our normal shell image activator. If it succeeds attempt 235 * to use the alternate path for the interpreter. If an 236 * alternate path is found, use our stringspace to store it. 237 */ 238 if ((error = exec_shell_imgact(imgp)) == 0) { 239 linux_emul_convpath(imgp->interpreter_name, UIO_SYSSPACE, 240 &rpath, 0, AT_FDCWD); 241 if (rpath != NULL) 242 imgp->args->fname_buf = 243 imgp->interpreter_name = rpath; 244 } 245 } 246 return (error); 247 } 248 249 int 250 linux_common_execve(struct thread *td, struct image_args *eargs) 251 { 252 struct linux_pemuldata *pem; 253 struct vmspace *oldvmspace; 254 struct linux_emuldata *em; 255 struct proc *p; 256 int error; 257 258 p = td->td_proc; 259 260 error = pre_execve(td, &oldvmspace); 261 if (error != 0) 262 return (error); 263 264 error = kern_execve(td, eargs, NULL, oldvmspace); 265 post_execve(td, error, oldvmspace); 266 if (error != EJUSTRETURN) 267 return (error); 268 269 /* 270 * In a case of transition from Linux binary execing to 271 * FreeBSD binary we destroy Linux emuldata thread & proc entries. 272 */ 273 if (SV_CURPROC_ABI() != SV_ABI_LINUX) { 274 PROC_LOCK(p); 275 em = em_find(td); 276 KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n")); 277 td->td_emuldata = NULL; 278 279 pem = pem_find(p); 280 KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n")); 281 p->p_emuldata = NULL; 282 PROC_UNLOCK(p); 283 284 free(em, M_TEMP); 285 free(pem, M_LINUX); 286 } 287 return (EJUSTRETURN); 288 } 289 290 void 291 linux_on_exec(struct proc *p, struct image_params *imgp) 292 { 293 struct thread *td; 294 struct thread *othertd; 295 #if defined(__amd64__) 296 struct linux_pemuldata *pem; 297 #endif 298 299 td = curthread; 300 MPASS((imgp->sysent->sv_flags & SV_ABI_MASK) == SV_ABI_LINUX); 301 302 /* 303 * When execing to Linux binary, we create Linux emuldata 304 * thread entry. 305 */ 306 if (SV_PROC_ABI(p) == SV_ABI_LINUX) { 307 /* 308 * Process already was under Linuxolator 309 * before exec. Update emuldata to reflect 310 * single-threaded cleaned state after exec. 311 */ 312 linux_proc_init(td, NULL, false); 313 } else { 314 /* 315 * We are switching the process to Linux emulator. 316 */ 317 linux_proc_init(td, td, false); 318 319 /* 320 * Create a transient td_emuldata for all suspended 321 * threads, so that p->p_sysent->sv_thread_detach() == 322 * linux_thread_detach() can find expected but unused 323 * emuldata. 324 */ 325 FOREACH_THREAD_IN_PROC(td->td_proc, othertd) { 326 if (othertd == td) 327 continue; 328 linux_proc_init(td, othertd, true); 329 } 330 } 331 #if defined(__amd64__) 332 /* 333 * An IA32 executable which has executable stack will have the 334 * READ_IMPLIES_EXEC personality flag set automatically. 335 */ 336 if (SV_PROC_FLAG(td->td_proc, SV_ILP32) && 337 imgp->stack_prot & VM_PROT_EXECUTE) { 338 pem = pem_find(p); 339 pem->persona |= LINUX_READ_IMPLIES_EXEC; 340 } 341 #endif 342 } 343 344 void 345 linux_thread_dtor(struct thread *td) 346 { 347 struct linux_emuldata *em; 348 349 em = em_find(td); 350 if (em == NULL) 351 return; 352 td->td_emuldata = NULL; 353 354 LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid); 355 356 free(em, M_TEMP); 357 } 358 359 void 360 linux_schedtail(struct thread *td) 361 { 362 struct linux_emuldata *em; 363 #ifdef KTR 364 int error; 365 #else 366 int error __unused; 367 #endif 368 int *child_set_tid; 369 370 em = em_find(td); 371 KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n")); 372 child_set_tid = em->child_set_tid; 373 374 if (child_set_tid != NULL) { 375 error = copyout(&em->em_tid, child_set_tid, 376 sizeof(em->em_tid)); 377 LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d", 378 td->td_tid, child_set_tid, em->em_tid, error); 379 } else 380 LINUX_CTR1(schedtail, "thread(%d)", em->em_tid); 381 } 382