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/param.h> 32 #include <sys/fcntl.h> 33 #include <sys/imgact.h> 34 #include <sys/ktr.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/mutex.h> 38 #include <sys/proc.h> 39 #include <sys/resourcevar.h> 40 #include <sys/sx.h> 41 #include <sys/syscallsubr.h> 42 #include <sys/sysent.h> 43 44 #include <compat/linux/linux_emul.h> 45 #include <compat/linux/linux_mib.h> 46 #include <compat/linux/linux_misc.h> 47 #include <compat/linux/linux_persona.h> 48 #include <compat/linux/linux_util.h> 49 50 #if BYTE_ORDER == LITTLE_ENDIAN 51 #define SHELLMAGIC 0x2123 /* #! */ 52 #else 53 #define SHELLMAGIC 0x2321 54 #endif 55 56 /* 57 * This returns reference to the thread emuldata entry (if found) 58 * 59 * Hold PROC_LOCK when referencing emuldata from other threads. 60 */ 61 struct linux_emuldata * em_find(struct thread * td)62 em_find(struct thread *td) 63 { 64 struct linux_emuldata *em; 65 66 em = td->td_emuldata; 67 68 return (em); 69 } 70 71 /* 72 * This returns reference to the proc pemuldata entry (if found) 73 * 74 * Hold PROC_LOCK when referencing proc pemuldata from other threads. 75 * Hold LINUX_PEM_LOCK wher referencing pemuldata members. 76 */ 77 struct linux_pemuldata * pem_find(struct proc * p)78 pem_find(struct proc *p) 79 { 80 struct linux_pemuldata *pem; 81 82 pem = p->p_emuldata; 83 84 return (pem); 85 } 86 87 /* 88 * Linux apps generally expect the soft open file limit to be set 89 * to 1024, often iterating over all the file descriptors up to that 90 * limit instead of using closefrom(2). Give them what they want, 91 * unless there already is a resource limit in place. 92 */ 93 static void linux_set_default_openfiles(struct thread * td,struct proc * p)94 linux_set_default_openfiles(struct thread *td, struct proc *p) 95 { 96 struct rlimit rlim; 97 int error __diagused; 98 99 if (linux_default_openfiles < 0) 100 return; 101 102 PROC_LOCK(p); 103 lim_rlimit_proc(p, RLIMIT_NOFILE, &rlim); 104 PROC_UNLOCK(p); 105 if (rlim.rlim_cur != rlim.rlim_max || 106 rlim.rlim_cur <= linux_default_openfiles) 107 return; 108 rlim.rlim_cur = linux_default_openfiles; 109 error = kern_proc_setrlimit(td, p, RLIMIT_NOFILE, &rlim); 110 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 111 } 112 113 /* 114 * The default stack size limit in Linux is 8MB. 115 */ 116 static void linux_set_default_stacksize(struct thread * td,struct proc * p)117 linux_set_default_stacksize(struct thread *td, struct proc *p) 118 { 119 struct rlimit rlim; 120 int error __diagused; 121 122 if (linux_default_stacksize < 0) 123 return; 124 125 PROC_LOCK(p); 126 lim_rlimit_proc(p, RLIMIT_STACK, &rlim); 127 PROC_UNLOCK(p); 128 if (rlim.rlim_cur != rlim.rlim_max || 129 rlim.rlim_cur <= linux_default_stacksize) 130 return; 131 rlim.rlim_cur = linux_default_stacksize; 132 error = kern_proc_setrlimit(td, p, RLIMIT_STACK, &rlim); 133 KASSERT(error == 0, ("kern_proc_setrlimit failed")); 134 } 135 136 void linux_proc_init(struct thread * td,struct thread * newtd,bool init_thread)137 linux_proc_init(struct thread *td, struct thread *newtd, bool init_thread) 138 { 139 struct linux_emuldata *em; 140 struct linux_pemuldata *pem; 141 struct proc *p; 142 143 if (newtd != NULL) { 144 p = newtd->td_proc; 145 146 /* non-exec call */ 147 em = malloc(sizeof(*em), M_LINUX, M_WAITOK | M_ZERO); 148 if (init_thread) { 149 LINUX_CTR1(proc_init, "thread newtd(%d)", 150 newtd->td_tid); 151 152 em->em_tid = newtd->td_tid; 153 } else { 154 LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid); 155 156 em->em_tid = p->p_pid; 157 158 pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO); 159 sx_init(&pem->pem_sx, "lpemlk"); 160 p->p_emuldata = pem; 161 } 162 newtd->td_emuldata = em; 163 164 linux_set_default_openfiles(td, p); 165 linux_set_default_stacksize(td, p); 166 } else { 167 p = td->td_proc; 168 169 /* exec */ 170 LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid); 171 172 /* lookup the old one */ 173 em = em_find(td); 174 KASSERT(em != NULL, ("proc_init: thread emuldata not found.\n")); 175 176 em->em_tid = p->p_pid; 177 em->flags = 0; 178 em->robust_futexes = NULL; 179 em->child_clear_tid = NULL; 180 em->child_set_tid = NULL; 181 182 pem = pem_find(p); 183 KASSERT(pem != NULL, ("proc_init: proc emuldata not found.\n")); 184 pem->persona = 0; 185 pem->oom_score_adj = 0; 186 } 187 } 188 189 void linux_on_exit(struct proc * p)190 linux_on_exit(struct proc *p) 191 { 192 struct linux_pemuldata *pem; 193 struct thread *td = curthread; 194 195 MPASS(SV_CURPROC_ABI() == SV_ABI_LINUX); 196 197 LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p", 198 td->td_tid, p->p_pid, p); 199 200 pem = pem_find(p); 201 if (pem == NULL) 202 return; 203 (p->p_sysent->sv_thread_detach)(td); 204 205 p->p_emuldata = NULL; 206 207 sx_destroy(&pem->pem_sx); 208 free(pem, M_LINUX); 209 } 210 211 int linux_common_execve(struct thread * td,struct image_args * eargs)212 linux_common_execve(struct thread *td, struct image_args *eargs) 213 { 214 struct linux_pemuldata *pem; 215 struct vmspace *oldvmspace; 216 struct linux_emuldata *em; 217 struct proc *p; 218 int error; 219 220 p = td->td_proc; 221 222 error = pre_execve(td, &oldvmspace); 223 if (error != 0) 224 return (error); 225 226 error = kern_execve(td, eargs, NULL, oldvmspace); 227 post_execve(td, error, oldvmspace); 228 if (error != EJUSTRETURN) 229 return (error); 230 231 /* 232 * In a case of transition from Linux binary execing to 233 * FreeBSD binary we destroy Linux emuldata thread & proc entries. 234 */ 235 if (SV_CURPROC_ABI() != SV_ABI_LINUX) { 236 237 /* Clear ABI root directory if set. */ 238 linux_pwd_onexec_native(td); 239 240 PROC_LOCK(p); 241 em = em_find(td); 242 KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n")); 243 td->td_emuldata = NULL; 244 245 pem = pem_find(p); 246 KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n")); 247 p->p_emuldata = NULL; 248 PROC_UNLOCK(p); 249 250 free(em, M_LINUX); 251 free(pem, M_LINUX); 252 } 253 return (EJUSTRETURN); 254 } 255 256 int linux_on_exec(struct proc * p,struct image_params * imgp)257 linux_on_exec(struct proc *p, struct image_params *imgp) 258 { 259 struct thread *td; 260 struct thread *othertd; 261 #if defined(__amd64__) 262 struct linux_pemuldata *pem; 263 #endif 264 int error; 265 266 td = curthread; 267 MPASS((imgp->sysent->sv_flags & SV_ABI_MASK) == SV_ABI_LINUX); 268 269 /* 270 * When execing to Linux binary, we create Linux emuldata 271 * thread entry. 272 */ 273 if (SV_PROC_ABI(p) == SV_ABI_LINUX) { 274 /* 275 * Process already was under Linuxolator 276 * before exec. Update emuldata to reflect 277 * single-threaded cleaned state after exec. 278 */ 279 linux_proc_init(td, NULL, false); 280 } else { 281 /* 282 * We are switching the process to Linux emulator. 283 */ 284 linux_proc_init(td, td, false); 285 286 /* 287 * Create a transient td_emuldata for all suspended 288 * threads, so that p->p_sysent->sv_thread_detach() == 289 * linux_thread_detach() can find expected but unused 290 * emuldata. 291 */ 292 FOREACH_THREAD_IN_PROC(td->td_proc, othertd) { 293 if (othertd == td) 294 continue; 295 linux_proc_init(td, othertd, true); 296 } 297 298 /* Set ABI root directory. */ 299 if ((error = linux_pwd_onexec(td)) != 0) 300 return (error); 301 } 302 #if defined(__amd64__) 303 /* 304 * An IA32 executable which has executable stack will have the 305 * READ_IMPLIES_EXEC personality flag set automatically. 306 */ 307 if (SV_PROC_FLAG(td->td_proc, SV_ILP32) && 308 imgp->stack_prot & VM_PROT_EXECUTE) { 309 pem = pem_find(p); 310 pem->persona |= LINUX_READ_IMPLIES_EXEC; 311 } 312 #endif 313 return (0); 314 } 315 316 void linux_thread_dtor(struct thread * td)317 linux_thread_dtor(struct thread *td) 318 { 319 struct linux_emuldata *em; 320 321 em = em_find(td); 322 if (em == NULL) 323 return; 324 td->td_emuldata = NULL; 325 326 LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid); 327 328 free(em, M_LINUX); 329 } 330 331 void linux_schedtail(struct thread * td)332 linux_schedtail(struct thread *td) 333 { 334 struct linux_emuldata *em; 335 #ifdef KTR 336 int error; 337 #else 338 int error __unused; 339 #endif 340 int *child_set_tid; 341 342 em = em_find(td); 343 KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n")); 344 child_set_tid = em->child_set_tid; 345 346 if (child_set_tid != NULL) { 347 error = copyout(&em->em_tid, child_set_tid, 348 sizeof(em->em_tid)); 349 LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d", 350 td->td_tid, child_set_tid, em->em_tid, error); 351 } else 352 LINUX_CTR1(schedtail, "thread(%d)", em->em_tid); 353 } 354