linux_fork.c revision 289672
1/*- 2 * Copyright (c) 2004 Tim J. Robbins 3 * Copyright (c) 2002 Doug Rabson 4 * Copyright (c) 2000 Marcel Moolenaar 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer 12 * in this position and unchanged. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: stable/10/sys/compat/linux/linux_fork.c 289672 2015-10-21 01:41:22Z bdrewery $"); 31 32#include "opt_compat.h" 33#include "opt_kdtrace.h" 34 35#include <sys/param.h> 36#include <sys/systm.h> 37#include <sys/imgact.h> 38#include <sys/lock.h> 39#include <sys/mutex.h> 40#include <sys/proc.h> 41#include <sys/sched.h> 42#include <sys/sdt.h> 43#include <sys/sx.h> 44#include <sys/unistd.h> 45 46#ifdef COMPAT_LINUX32 47#include <machine/../linux32/linux.h> 48#include <machine/../linux32/linux32_proto.h> 49#else 50#include <machine/../linux/linux.h> 51#include <machine/../linux/linux_proto.h> 52#endif 53#include <compat/linux/linux_dtrace.h> 54#include <compat/linux/linux_signal.h> 55#include <compat/linux/linux_emul.h> 56#include <compat/linux/linux_misc.h> 57 58/* DTrace init */ 59LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); 60 61/* Linuxulator-global DTrace probes */ 62LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked); 63LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock); 64 65 66int 67linux_fork(struct thread *td, struct linux_fork_args *args) 68{ 69 int error; 70 struct proc *p2; 71 struct thread *td2; 72 73#ifdef DEBUG 74 if (ldebug(fork)) 75 printf(ARGS(fork, "")); 76#endif 77 78 if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2, NULL, 0)) 79 != 0) 80 return (error); 81 82 td->td_retval[0] = p2->p_pid; 83 td->td_retval[1] = 0; 84 85 error = linux_proc_init(td, td->td_retval[0], 0); 86 if (error) 87 return (error); 88 89 td2 = FIRST_THREAD_IN_PROC(p2); 90 91 /* 92 * Make this runnable after we are finished with it. 93 */ 94 thread_lock(td2); 95 TD_SET_CAN_RUN(td2); 96 sched_add(td2, SRQ_BORING); 97 thread_unlock(td2); 98 99 return (0); 100} 101 102int 103linux_vfork(struct thread *td, struct linux_vfork_args *args) 104{ 105 int error; 106 struct proc *p2; 107 struct thread *td2; 108 109#ifdef DEBUG 110 if (ldebug(vfork)) 111 printf(ARGS(vfork, "")); 112#endif 113 114 if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED, 115 0, &p2, NULL, 0)) != 0) 116 return (error); 117 118 td->td_retval[0] = p2->p_pid; 119 120 error = linux_proc_init(td, td->td_retval[0], 0); 121 if (error) 122 return (error); 123 124 td2 = FIRST_THREAD_IN_PROC(p2); 125 126 /* 127 * Make this runnable after we are finished with it. 128 */ 129 thread_lock(td2); 130 TD_SET_CAN_RUN(td2); 131 sched_add(td2, SRQ_BORING); 132 thread_unlock(td2); 133 134 return (0); 135} 136 137int 138linux_clone(struct thread *td, struct linux_clone_args *args) 139{ 140 int error, ff = RFPROC | RFSTOPPED; 141 struct proc *p2; 142 struct thread *td2; 143 int exit_signal; 144 struct linux_emuldata *em; 145 146#ifdef DEBUG 147 if (ldebug(clone)) { 148 printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, " 149 "child tid: %p"), (unsigned)args->flags, 150 args->stack, args->parent_tidptr, args->child_tidptr); 151 } 152#endif 153 154 exit_signal = args->flags & 0x000000ff; 155 if (LINUX_SIG_VALID(exit_signal)) { 156 if (exit_signal <= LINUX_SIGTBLSZ) 157 exit_signal = 158 linux_to_bsd_signal[_SIG_IDX(exit_signal)]; 159 } else if (exit_signal != 0) 160 return (EINVAL); 161 162 if (args->flags & LINUX_CLONE_VM) 163 ff |= RFMEM; 164 if (args->flags & LINUX_CLONE_SIGHAND) 165 ff |= RFSIGSHARE; 166 /* 167 * XXX: In Linux, sharing of fs info (chroot/cwd/umask) 168 * and open files is independant. In FreeBSD, its in one 169 * structure but in reality it does not cause any problems 170 * because both of these flags are usually set together. 171 */ 172 if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS))) 173 ff |= RFFDG; 174 175 /* 176 * Attempt to detect when linux_clone(2) is used for creating 177 * kernel threads. Unfortunately despite the existence of the 178 * CLONE_THREAD flag, version of linuxthreads package used in 179 * most popular distros as of beginning of 2005 doesn't make 180 * any use of it. Therefore, this detection relies on 181 * empirical observation that linuxthreads sets certain 182 * combination of flags, so that we can make more or less 183 * precise detection and notify the FreeBSD kernel that several 184 * processes are in fact part of the same threading group, so 185 * that special treatment is necessary for signal delivery 186 * between those processes and fd locking. 187 */ 188 if ((args->flags & 0xffffff00) == LINUX_THREADING_FLAGS) 189 ff |= RFTHREAD; 190 191 if (args->flags & LINUX_CLONE_PARENT_SETTID) 192 if (args->parent_tidptr == NULL) 193 return (EINVAL); 194 195 if (args->flags & LINUX_CLONE_VFORK) 196 ff |= RFPPWAIT; 197 198 error = fork1(td, ff, 0, &p2, NULL, 0); 199 if (error) 200 return (error); 201 202 if (args->flags & (LINUX_CLONE_PARENT | LINUX_CLONE_THREAD)) { 203 sx_xlock(&proctree_lock); 204 PROC_LOCK(p2); 205 proc_reparent(p2, td->td_proc->p_pptr); 206 PROC_UNLOCK(p2); 207 sx_xunlock(&proctree_lock); 208 } 209 210 /* create the emuldata */ 211 error = linux_proc_init(td, p2->p_pid, args->flags); 212 /* reference it - no need to check this */ 213 em = em_find(p2, EMUL_DOLOCK); 214 KASSERT(em != NULL, ("clone: emuldata not found.")); 215 /* and adjust it */ 216 217 if (args->flags & LINUX_CLONE_THREAD) { 218#ifdef notyet 219 PROC_LOCK(p2); 220 p2->p_pgrp = td->td_proc->p_pgrp; 221 PROC_UNLOCK(p2); 222#endif 223 exit_signal = 0; 224 } 225 226 if (args->flags & LINUX_CLONE_CHILD_SETTID) 227 em->child_set_tid = args->child_tidptr; 228 else 229 em->child_set_tid = NULL; 230 231 if (args->flags & LINUX_CLONE_CHILD_CLEARTID) 232 em->child_clear_tid = args->child_tidptr; 233 else 234 em->child_clear_tid = NULL; 235 236 EMUL_UNLOCK(&emul_lock); 237 238 if (args->flags & LINUX_CLONE_PARENT_SETTID) { 239 error = copyout(&p2->p_pid, args->parent_tidptr, 240 sizeof(p2->p_pid)); 241 if (error) 242 printf(LMSG("copyout failed!")); 243 } 244 245 PROC_LOCK(p2); 246 p2->p_sigparent = exit_signal; 247 PROC_UNLOCK(p2); 248 td2 = FIRST_THREAD_IN_PROC(p2); 249 /* 250 * In a case of stack = NULL, we are supposed to COW calling process 251 * stack. This is what normal fork() does, so we just keep tf_rsp arg 252 * intact. 253 */ 254 if (args->stack) 255 linux_set_upcall_kse(td2, PTROUT(args->stack)); 256 257 if (args->flags & LINUX_CLONE_SETTLS) 258 linux_set_cloned_tls(td2, args->tls); 259 260#ifdef DEBUG 261 if (ldebug(clone)) 262 printf(LMSG("clone: successful rfork to %d, " 263 "stack %p sig = %d"), (int)p2->p_pid, args->stack, 264 exit_signal); 265#endif 266 /* 267 * Make this runnable after we are finished with it. 268 */ 269 thread_lock(td2); 270 TD_SET_CAN_RUN(td2); 271 sched_add(td2, SRQ_BORING); 272 thread_unlock(td2); 273 274 td->td_retval[0] = p2->p_pid; 275 td->td_retval[1] = 0; 276 277 return (0); 278} 279