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 /* 119 * The default stack size limit in Linux is 8MB. 120 */ 121 static void 122 linux_set_default_stacksize(struct thread *td, struct proc *p) 123 { 124 struct rlimit rlim; 125 int error; 126 127 if (linux_default_stacksize < 0) 128 return; 129 130 PROC_LOCK(p); 131 lim_rlimit_proc(p, RLIMIT_STACK, &rlim); 132 PROC_UNLOCK(p); 133 if (rlim.rlim_cur != rlim.rlim_max || 134 rlim.rlim_cur <= linux_default_stacksize) 135 return; 136 rlim.rlim_cur = linux_default_stacksize; 137 error = kern_proc_setrlimit(td, p, RLIMIT_STACK, &rlim); 138 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 139 } 140 141 void 142 linux_proc_init(struct thread *td, struct thread *newtd, int flags) 143 { 144 struct linux_emuldata *em; 145 struct linux_pemuldata *pem; 146 struct proc *p; 147 148 if (newtd != NULL) { 149 p = newtd->td_proc; 150 151 /* non-exec call */ 152 em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO); 153 if (flags & LINUX_CLONE_THREAD) { 154 LINUX_CTR1(proc_init, "thread newtd(%d)", 155 newtd->td_tid); 156 157 em->em_tid = newtd->td_tid; 158 } else { 159 LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid); 160 161 em->em_tid = p->p_pid; 162 163 pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO); 164 sx_init(&pem->pem_sx, "lpemlk"); 165 p->p_emuldata = pem; 166 } 167 newtd->td_emuldata = em; 168 169 linux_set_default_openfiles(td, p); 170 linux_set_default_stacksize(td, p); 171 } else { 172 p = td->td_proc; 173 174 /* exec */ 175 LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid); 176 177 /* lookup the old one */ 178 em = em_find(td); 179 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n")); 180 181 em->em_tid = p->p_pid; 182 em->flags = 0; 183 em->robust_futexes = NULL; 184 em->child_clear_tid = NULL; 185 em->child_set_tid = NULL; 186 187 pem = pem_find(p); 188 KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n")); 189 pem->persona = 0; 190 } 191 192 } 193 194 void 195 linux_on_exit(struct proc *p) 196 { 197 struct linux_pemuldata *pem; 198 struct thread *td = curthread; 199 200 MPASS(SV_CURPROC_ABI() == SV_ABI_LINUX); 201 202 LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p", 203 td->td_tid, p->p_pid, p); 204 205 pem = pem_find(p); 206 if (pem == NULL) 207 return; 208 (p->p_sysent->sv_thread_detach)(td); 209 210 p->p_emuldata = NULL; 211 212 sx_destroy(&pem->pem_sx); 213 free(pem, M_LINUX); 214 } 215 216 /* 217 * If a Linux binary is exec'ing something, try this image activator 218 * first. We override standard shell script execution in order to 219 * be able to modify the interpreter path. We only do this if a Linux 220 * binary is doing the exec, so we do not create an EXEC module for it. 221 */ 222 int 223 linux_exec_imgact_try(struct image_params *imgp) 224 { 225 const char *head = (const char *)imgp->image_header; 226 char *rpath; 227 int error = -1; 228 229 /* 230 * The interpreter for shell scripts run from a Linux binary needs 231 * to be located in /compat/linux if possible in order to recursively 232 * maintain Linux path emulation. 233 */ 234 if (((const short *)head)[0] == SHELLMAGIC) { 235 /* 236 * Run our normal shell image activator. If it succeeds attempt 237 * to use the alternate path for the interpreter. If an 238 * alternate path is found, use our stringspace to store it. 239 */ 240 if ((error = exec_shell_imgact(imgp)) == 0) { 241 linux_emul_convpath(FIRST_THREAD_IN_PROC(imgp->proc), 242 imgp->interpreter_name, UIO_SYSSPACE, &rpath, 0, 243 AT_FDCWD); 244 if (rpath != NULL) 245 imgp->args->fname_buf = 246 imgp->interpreter_name = rpath; 247 } 248 } 249 return (error); 250 } 251 252 int 253 linux_common_execve(struct thread *td, struct image_args *eargs) 254 { 255 struct linux_pemuldata *pem; 256 struct vmspace *oldvmspace; 257 struct linux_emuldata *em; 258 struct proc *p; 259 int error; 260 261 p = td->td_proc; 262 263 error = pre_execve(td, &oldvmspace); 264 if (error != 0) 265 return (error); 266 267 error = kern_execve(td, eargs, NULL, oldvmspace); 268 post_execve(td, error, oldvmspace); 269 if (error != EJUSTRETURN) 270 return (error); 271 272 /* 273 * In a case of transition from Linux binary execing to 274 * FreeBSD binary we destroy Linux emuldata thread & proc entries. 275 */ 276 if (SV_CURPROC_ABI() != SV_ABI_LINUX) { 277 PROC_LOCK(p); 278 em = em_find(td); 279 KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n")); 280 td->td_emuldata = NULL; 281 282 pem = pem_find(p); 283 KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n")); 284 p->p_emuldata = NULL; 285 PROC_UNLOCK(p); 286 287 free(em, M_TEMP); 288 free(pem, M_LINUX); 289 } 290 return (EJUSTRETURN); 291 } 292 293 void 294 linux_on_exec(struct proc *p, struct image_params *imgp) 295 { 296 struct thread *td; 297 struct thread *othertd; 298 #if defined(__amd64__) 299 struct linux_pemuldata *pem; 300 #endif 301 302 td = curthread; 303 MPASS((imgp->sysent->sv_flags & SV_ABI_MASK) == SV_ABI_LINUX); 304 305 /* 306 * When execing to Linux binary, we create Linux emuldata 307 * thread entry. 308 */ 309 if (SV_PROC_ABI(p) == SV_ABI_LINUX) { 310 /* 311 * Process already was under Linuxolator 312 * before exec. Update emuldata to reflect 313 * single-threaded cleaned state after exec. 314 */ 315 linux_proc_init(td, NULL, 0); 316 } else { 317 /* 318 * We are switching the process to Linux emulator. 319 */ 320 linux_proc_init(td, td, 0); 321 322 /* 323 * Create a transient td_emuldata for all suspended 324 * threads, so that p->p_sysent->sv_thread_detach() == 325 * linux_thread_detach() can find expected but unused 326 * emuldata. 327 */ 328 FOREACH_THREAD_IN_PROC(td->td_proc, othertd) { 329 if (othertd == td) 330 continue; 331 linux_proc_init(td, othertd, LINUX_CLONE_THREAD); 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 void 348 linux_thread_dtor(struct thread *td) 349 { 350 struct linux_emuldata *em; 351 352 em = em_find(td); 353 if (em == NULL) 354 return; 355 td->td_emuldata = NULL; 356 357 LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid); 358 359 free(em, M_TEMP); 360 } 361 362 void 363 linux_schedtail(struct thread *td) 364 { 365 struct linux_emuldata *em; 366 struct proc *p; 367 int error = 0; 368 int *child_set_tid; 369 370 p = td->td_proc; 371 372 em = em_find(td); 373 KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n")); 374 child_set_tid = em->child_set_tid; 375 376 if (child_set_tid != NULL) { 377 error = copyout(&em->em_tid, child_set_tid, 378 sizeof(em->em_tid)); 379 LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d", 380 td->td_tid, child_set_tid, em->em_tid, error); 381 } else 382 LINUX_CTR1(schedtail, "thread(%d)", em->em_tid); 383 } 384