1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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_LINUX, 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 int 215 linux_common_execve(struct thread *td, struct image_args *eargs) 216 { 217 struct linux_pemuldata *pem; 218 struct vmspace *oldvmspace; 219 struct linux_emuldata *em; 220 struct proc *p; 221 int error; 222 223 p = td->td_proc; 224 225 error = pre_execve(td, &oldvmspace); 226 if (error != 0) 227 return (error); 228 229 error = kern_execve(td, eargs, NULL, oldvmspace); 230 post_execve(td, error, oldvmspace); 231 if (error != EJUSTRETURN) 232 return (error); 233 234 /* 235 * In a case of transition from Linux binary execing to 236 * FreeBSD binary we destroy Linux emuldata thread & proc entries. 237 */ 238 if (SV_CURPROC_ABI() != SV_ABI_LINUX) { 239 240 /* Clear ABI root directory if set. */ 241 linux_pwd_onexec_native(td); 242 243 PROC_LOCK(p); 244 em = em_find(td); 245 KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n")); 246 td->td_emuldata = NULL; 247 248 pem = pem_find(p); 249 KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n")); 250 p->p_emuldata = NULL; 251 PROC_UNLOCK(p); 252 253 free(em, M_LINUX); 254 free(pem, M_LINUX); 255 } 256 return (EJUSTRETURN); 257 } 258 259 int 260 linux_on_exec(struct proc *p, struct image_params *imgp) 261 { 262 struct thread *td; 263 struct thread *othertd; 264 #if defined(__amd64__) 265 struct linux_pemuldata *pem; 266 #endif 267 int error; 268 269 td = curthread; 270 MPASS((imgp->sysent->sv_flags & SV_ABI_MASK) == SV_ABI_LINUX); 271 272 /* 273 * When execing to Linux binary, we create Linux emuldata 274 * thread entry. 275 */ 276 if (SV_PROC_ABI(p) == SV_ABI_LINUX) { 277 /* 278 * Process already was under Linuxolator 279 * before exec. Update emuldata to reflect 280 * single-threaded cleaned state after exec. 281 */ 282 linux_proc_init(td, NULL, false); 283 } else { 284 /* 285 * We are switching the process to Linux emulator. 286 */ 287 linux_proc_init(td, td, false); 288 289 /* 290 * Create a transient td_emuldata for all suspended 291 * threads, so that p->p_sysent->sv_thread_detach() == 292 * linux_thread_detach() can find expected but unused 293 * emuldata. 294 */ 295 FOREACH_THREAD_IN_PROC(td->td_proc, othertd) { 296 if (othertd == td) 297 continue; 298 linux_proc_init(td, othertd, true); 299 } 300 301 /* Set ABI root directory. */ 302 if ((error = linux_pwd_onexec(td)) != 0) 303 return (error); 304 } 305 #if defined(__amd64__) 306 /* 307 * An IA32 executable which has executable stack will have the 308 * READ_IMPLIES_EXEC personality flag set automatically. 309 */ 310 if (SV_PROC_FLAG(td->td_proc, SV_ILP32) && 311 imgp->stack_prot & VM_PROT_EXECUTE) { 312 pem = pem_find(p); 313 pem->persona |= LINUX_READ_IMPLIES_EXEC; 314 } 315 #endif 316 return (0); 317 } 318 319 void 320 linux_thread_dtor(struct thread *td) 321 { 322 struct linux_emuldata *em; 323 324 em = em_find(td); 325 if (em == NULL) 326 return; 327 td->td_emuldata = NULL; 328 329 LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid); 330 331 free(em, M_LINUX); 332 } 333 334 void 335 linux_schedtail(struct thread *td) 336 { 337 struct linux_emuldata *em; 338 #ifdef KTR 339 int error; 340 #else 341 int error __unused; 342 #endif 343 int *child_set_tid; 344 345 em = em_find(td); 346 KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n")); 347 child_set_tid = em->child_set_tid; 348 349 if (child_set_tid != NULL) { 350 error = copyout(&em->em_tid, child_set_tid, 351 sizeof(em->em_tid)); 352 LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d", 353 td->td_tid, child_set_tid, em->em_tid, error); 354 } else 355 LINUX_CTR1(schedtail, "thread(%d)", em->em_tid); 356 } 357