| 1 | /* $NetBSD: kern_fork.c,v 1.196 2016/11/04 18:14:04 christos Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, |
| 9 | * NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without |
| 12 | * modification, are permitted provided that the following conditions |
| 13 | * are met: |
| 14 | * 1. Redistributions of source code must retain the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer in the |
| 18 | * documentation and/or other materials provided with the distribution. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 30 | * POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * Copyright (c) 1982, 1986, 1989, 1991, 1993 |
| 35 | * The Regents of the University of California. All rights reserved. |
| 36 | * (c) UNIX System Laboratories, Inc. |
| 37 | * All or some portions of this file are derived from material licensed |
| 38 | * to the University of California by American Telephone and Telegraph |
| 39 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
| 40 | * the permission of UNIX System Laboratories, Inc. |
| 41 | * |
| 42 | * Redistribution and use in source and binary forms, with or without |
| 43 | * modification, are permitted provided that the following conditions |
| 44 | * are met: |
| 45 | * 1. Redistributions of source code must retain the above copyright |
| 46 | * notice, this list of conditions and the following disclaimer. |
| 47 | * 2. Redistributions in binary form must reproduce the above copyright |
| 48 | * notice, this list of conditions and the following disclaimer in the |
| 49 | * documentation and/or other materials provided with the distribution. |
| 50 | * 3. Neither the name of the University nor the names of its contributors |
| 51 | * may be used to endorse or promote products derived from this software |
| 52 | * without specific prior written permission. |
| 53 | * |
| 54 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 55 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 56 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 57 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 58 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 59 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 60 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 61 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 62 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 63 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 64 | * SUCH DAMAGE. |
| 65 | * |
| 66 | * @(#)kern_fork.c 8.8 (Berkeley) 2/14/95 |
| 67 | */ |
| 68 | |
| 69 | #include <sys/cdefs.h> |
| 70 | __KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.196 2016/11/04 18:14:04 christos Exp $" ); |
| 71 | |
| 72 | #include "opt_ktrace.h" |
| 73 | #include "opt_dtrace.h" |
| 74 | |
| 75 | #include <sys/param.h> |
| 76 | #include <sys/systm.h> |
| 77 | #include <sys/filedesc.h> |
| 78 | #include <sys/kernel.h> |
| 79 | #include <sys/pool.h> |
| 80 | #include <sys/mount.h> |
| 81 | #include <sys/proc.h> |
| 82 | #include <sys/ras.h> |
| 83 | #include <sys/resourcevar.h> |
| 84 | #include <sys/vnode.h> |
| 85 | #include <sys/file.h> |
| 86 | #include <sys/acct.h> |
| 87 | #include <sys/ktrace.h> |
| 88 | #include <sys/sched.h> |
| 89 | #include <sys/signalvar.h> |
| 90 | #include <sys/kauth.h> |
| 91 | #include <sys/atomic.h> |
| 92 | #include <sys/syscallargs.h> |
| 93 | #include <sys/uidinfo.h> |
| 94 | #include <sys/sdt.h> |
| 95 | #include <sys/ptrace.h> |
| 96 | |
| 97 | #include <uvm/uvm_extern.h> |
| 98 | |
| 99 | /* |
| 100 | * DTrace SDT provider definitions |
| 101 | */ |
| 102 | SDT_PROVIDER_DECLARE(proc); |
| 103 | SDT_PROBE_DEFINE3(proc, kernel, , create, |
| 104 | "struct proc *" , /* new process */ |
| 105 | "struct proc *" , /* parent process */ |
| 106 | "int" /* flags */); |
| 107 | |
| 108 | u_int nprocs __cacheline_aligned = 1; /* process 0 */ |
| 109 | |
| 110 | /* |
| 111 | * Number of ticks to sleep if fork() would fail due to process hitting |
| 112 | * limits. Exported in miliseconds to userland via sysctl. |
| 113 | */ |
| 114 | int forkfsleep = 0; |
| 115 | |
| 116 | int |
| 117 | sys_fork(struct lwp *l, const void *v, register_t *retval) |
| 118 | { |
| 119 | |
| 120 | return fork1(l, 0, SIGCHLD, NULL, 0, NULL, NULL, retval, NULL); |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * vfork(2) system call compatible with 4.4BSD (i.e. BSD with Mach VM). |
| 125 | * Address space is not shared, but parent is blocked until child exit. |
| 126 | */ |
| 127 | int |
| 128 | sys_vfork(struct lwp *l, const void *v, register_t *retval) |
| 129 | { |
| 130 | |
| 131 | return fork1(l, FORK_PPWAIT, SIGCHLD, NULL, 0, NULL, NULL, |
| 132 | retval, NULL); |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * New vfork(2) system call for NetBSD, which implements original 3BSD vfork(2) |
| 137 | * semantics. Address space is shared, and parent is blocked until child exit. |
| 138 | */ |
| 139 | int |
| 140 | sys___vfork14(struct lwp *l, const void *v, register_t *retval) |
| 141 | { |
| 142 | |
| 143 | return fork1(l, FORK_PPWAIT|FORK_SHAREVM, SIGCHLD, NULL, 0, |
| 144 | NULL, NULL, retval, NULL); |
| 145 | } |
| 146 | |
| 147 | /* |
| 148 | * Linux-compatible __clone(2) system call. |
| 149 | */ |
| 150 | int |
| 151 | sys___clone(struct lwp *l, const struct sys___clone_args *uap, |
| 152 | register_t *retval) |
| 153 | { |
| 154 | /* { |
| 155 | syscallarg(int) flags; |
| 156 | syscallarg(void *) stack; |
| 157 | } */ |
| 158 | int flags, sig; |
| 159 | |
| 160 | /* |
| 161 | * We don't support the CLONE_PID or CLONE_PTRACE flags. |
| 162 | */ |
| 163 | if (SCARG(uap, flags) & (CLONE_PID|CLONE_PTRACE)) |
| 164 | return EINVAL; |
| 165 | |
| 166 | /* |
| 167 | * Linux enforces CLONE_VM with CLONE_SIGHAND, do same. |
| 168 | */ |
| 169 | if (SCARG(uap, flags) & CLONE_SIGHAND |
| 170 | && (SCARG(uap, flags) & CLONE_VM) == 0) |
| 171 | return EINVAL; |
| 172 | |
| 173 | flags = 0; |
| 174 | |
| 175 | if (SCARG(uap, flags) & CLONE_VM) |
| 176 | flags |= FORK_SHAREVM; |
| 177 | if (SCARG(uap, flags) & CLONE_FS) |
| 178 | flags |= FORK_SHARECWD; |
| 179 | if (SCARG(uap, flags) & CLONE_FILES) |
| 180 | flags |= FORK_SHAREFILES; |
| 181 | if (SCARG(uap, flags) & CLONE_SIGHAND) |
| 182 | flags |= FORK_SHARESIGS; |
| 183 | if (SCARG(uap, flags) & CLONE_VFORK) |
| 184 | flags |= FORK_PPWAIT; |
| 185 | |
| 186 | sig = SCARG(uap, flags) & CLONE_CSIGNAL; |
| 187 | if (sig < 0 || sig >= _NSIG) |
| 188 | return EINVAL; |
| 189 | |
| 190 | /* |
| 191 | * Note that the Linux API does not provide a portable way of |
| 192 | * specifying the stack area; the caller must know if the stack |
| 193 | * grows up or down. So, we pass a stack size of 0, so that the |
| 194 | * code that makes this adjustment is a noop. |
| 195 | */ |
| 196 | return fork1(l, flags, sig, SCARG(uap, stack), 0, |
| 197 | NULL, NULL, retval, NULL); |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Print the 'table full' message once per 10 seconds. |
| 202 | */ |
| 203 | static struct timeval fork_tfmrate = { 10, 0 }; |
| 204 | |
| 205 | /* |
| 206 | * General fork call. Note that another LWP in the process may call exec() |
| 207 | * or exit() while we are forking. It's safe to continue here, because |
| 208 | * neither operation will complete until all LWPs have exited the process. |
| 209 | */ |
| 210 | int |
| 211 | fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize, |
| 212 | void (*func)(void *), void *arg, register_t *retval, |
| 213 | struct proc **rnewprocp) |
| 214 | { |
| 215 | struct proc *p1, *p2, *parent; |
| 216 | struct plimit *p1_lim; |
| 217 | uid_t uid; |
| 218 | struct lwp *l2; |
| 219 | int count; |
| 220 | vaddr_t uaddr; |
| 221 | int tnprocs; |
| 222 | int tracefork; |
| 223 | int error = 0; |
| 224 | |
| 225 | p1 = l1->l_proc; |
| 226 | uid = kauth_cred_getuid(l1->l_cred); |
| 227 | tnprocs = atomic_inc_uint_nv(&nprocs); |
| 228 | |
| 229 | /* |
| 230 | * Although process entries are dynamically created, we still keep |
| 231 | * a global limit on the maximum number we will create. |
| 232 | */ |
| 233 | if (__predict_false(tnprocs >= maxproc)) |
| 234 | error = -1; |
| 235 | else |
| 236 | error = kauth_authorize_process(l1->l_cred, |
| 237 | KAUTH_PROCESS_FORK, p1, KAUTH_ARG(tnprocs), NULL, NULL); |
| 238 | |
| 239 | if (error) { |
| 240 | static struct timeval lasttfm; |
| 241 | atomic_dec_uint(&nprocs); |
| 242 | if (ratecheck(&lasttfm, &fork_tfmrate)) |
| 243 | tablefull("proc" , "increase kern.maxproc or NPROC" ); |
| 244 | if (forkfsleep) |
| 245 | kpause("forkmx" , false, forkfsleep, NULL); |
| 246 | return EAGAIN; |
| 247 | } |
| 248 | |
| 249 | /* |
| 250 | * Enforce limits. |
| 251 | */ |
| 252 | count = chgproccnt(uid, 1); |
| 253 | if (__predict_false(count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur)) { |
| 254 | if (kauth_authorize_process(l1->l_cred, KAUTH_PROCESS_RLIMIT, |
| 255 | p1, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS), |
| 256 | &p1->p_rlimit[RLIMIT_NPROC], KAUTH_ARG(RLIMIT_NPROC)) != 0) { |
| 257 | (void)chgproccnt(uid, -1); |
| 258 | atomic_dec_uint(&nprocs); |
| 259 | if (forkfsleep) |
| 260 | kpause("forkulim" , false, forkfsleep, NULL); |
| 261 | return EAGAIN; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | /* |
| 266 | * Allocate virtual address space for the U-area now, while it |
| 267 | * is still easy to abort the fork operation if we're out of |
| 268 | * kernel virtual address space. |
| 269 | */ |
| 270 | uaddr = uvm_uarea_alloc(); |
| 271 | if (__predict_false(uaddr == 0)) { |
| 272 | (void)chgproccnt(uid, -1); |
| 273 | atomic_dec_uint(&nprocs); |
| 274 | return ENOMEM; |
| 275 | } |
| 276 | |
| 277 | /* |
| 278 | * We are now committed to the fork. From here on, we may |
| 279 | * block on resources, but resource allocation may NOT fail. |
| 280 | */ |
| 281 | |
| 282 | /* Allocate new proc. */ |
| 283 | p2 = proc_alloc(); |
| 284 | |
| 285 | /* |
| 286 | * Make a proc table entry for the new process. |
| 287 | * Start by zeroing the section of proc that is zero-initialized, |
| 288 | * then copy the section that is copied directly from the parent. |
| 289 | */ |
| 290 | memset(&p2->p_startzero, 0, |
| 291 | (unsigned) ((char *)&p2->p_endzero - (char *)&p2->p_startzero)); |
| 292 | memcpy(&p2->p_startcopy, &p1->p_startcopy, |
| 293 | (unsigned) ((char *)&p2->p_endcopy - (char *)&p2->p_startcopy)); |
| 294 | |
| 295 | TAILQ_INIT(&p2->p_sigpend.sp_info); |
| 296 | |
| 297 | LIST_INIT(&p2->p_lwps); |
| 298 | LIST_INIT(&p2->p_sigwaiters); |
| 299 | |
| 300 | /* |
| 301 | * Duplicate sub-structures as needed. |
| 302 | * Increase reference counts on shared objects. |
| 303 | * Inherit flags we want to keep. The flags related to SIGCHLD |
| 304 | * handling are important in order to keep a consistent behaviour |
| 305 | * for the child after the fork. If we are a 32-bit process, the |
| 306 | * child will be too. |
| 307 | */ |
| 308 | p2->p_flag = |
| 309 | p1->p_flag & (PK_SUGID | PK_NOCLDWAIT | PK_CLDSIGIGN | PK_32); |
| 310 | p2->p_emul = p1->p_emul; |
| 311 | p2->p_execsw = p1->p_execsw; |
| 312 | |
| 313 | if (flags & FORK_SYSTEM) { |
| 314 | /* |
| 315 | * Mark it as a system process. Set P_NOCLDWAIT so that |
| 316 | * children are reparented to init(8) when they exit. |
| 317 | * init(8) can easily wait them out for us. |
| 318 | */ |
| 319 | p2->p_flag |= (PK_SYSTEM | PK_NOCLDWAIT); |
| 320 | } |
| 321 | |
| 322 | mutex_init(&p2->p_stmutex, MUTEX_DEFAULT, IPL_HIGH); |
| 323 | mutex_init(&p2->p_auxlock, MUTEX_DEFAULT, IPL_NONE); |
| 324 | rw_init(&p2->p_reflock); |
| 325 | cv_init(&p2->p_waitcv, "wait" ); |
| 326 | cv_init(&p2->p_lwpcv, "lwpwait" ); |
| 327 | |
| 328 | /* |
| 329 | * Share a lock between the processes if they are to share signal |
| 330 | * state: we must synchronize access to it. |
| 331 | */ |
| 332 | if (flags & FORK_SHARESIGS) { |
| 333 | p2->p_lock = p1->p_lock; |
| 334 | mutex_obj_hold(p1->p_lock); |
| 335 | } else |
| 336 | p2->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); |
| 337 | |
| 338 | kauth_proc_fork(p1, p2); |
| 339 | |
| 340 | p2->p_raslist = NULL; |
| 341 | #if defined(__HAVE_RAS) |
| 342 | ras_fork(p1, p2); |
| 343 | #endif |
| 344 | |
| 345 | /* bump references to the text vnode (for procfs) */ |
| 346 | p2->p_textvp = p1->p_textvp; |
| 347 | if (p2->p_textvp) |
| 348 | vref(p2->p_textvp); |
| 349 | |
| 350 | if (flags & FORK_SHAREFILES) |
| 351 | fd_share(p2); |
| 352 | else if (flags & FORK_CLEANFILES) |
| 353 | p2->p_fd = fd_init(NULL); |
| 354 | else |
| 355 | p2->p_fd = fd_copy(); |
| 356 | |
| 357 | /* XXX racy */ |
| 358 | p2->p_mqueue_cnt = p1->p_mqueue_cnt; |
| 359 | |
| 360 | if (flags & FORK_SHARECWD) |
| 361 | cwdshare(p2); |
| 362 | else |
| 363 | p2->p_cwdi = cwdinit(); |
| 364 | |
| 365 | /* |
| 366 | * Note: p_limit (rlimit stuff) is copy-on-write, so normally |
| 367 | * we just need increase pl_refcnt. |
| 368 | */ |
| 369 | p1_lim = p1->p_limit; |
| 370 | if (!p1_lim->pl_writeable) { |
| 371 | lim_addref(p1_lim); |
| 372 | p2->p_limit = p1_lim; |
| 373 | } else { |
| 374 | p2->p_limit = lim_copy(p1_lim); |
| 375 | } |
| 376 | |
| 377 | if (flags & FORK_PPWAIT) { |
| 378 | /* Mark ourselves as waiting for a child. */ |
| 379 | l1->l_pflag |= LP_VFORKWAIT; |
| 380 | p2->p_lflag = PL_PPWAIT; |
| 381 | p2->p_vforklwp = l1; |
| 382 | } else { |
| 383 | p2->p_lflag = 0; |
| 384 | } |
| 385 | p2->p_sflag = 0; |
| 386 | p2->p_slflag = 0; |
| 387 | parent = (flags & FORK_NOWAIT) ? initproc : p1; |
| 388 | p2->p_pptr = parent; |
| 389 | p2->p_ppid = parent->p_pid; |
| 390 | LIST_INIT(&p2->p_children); |
| 391 | |
| 392 | p2->p_aio = NULL; |
| 393 | |
| 394 | #ifdef KTRACE |
| 395 | /* |
| 396 | * Copy traceflag and tracefile if enabled. |
| 397 | * If not inherited, these were zeroed above. |
| 398 | */ |
| 399 | if (p1->p_traceflag & KTRFAC_INHERIT) { |
| 400 | mutex_enter(&ktrace_lock); |
| 401 | p2->p_traceflag = p1->p_traceflag; |
| 402 | if ((p2->p_tracep = p1->p_tracep) != NULL) |
| 403 | ktradref(p2); |
| 404 | mutex_exit(&ktrace_lock); |
| 405 | } |
| 406 | #endif |
| 407 | |
| 408 | /* |
| 409 | * Create signal actions for the child process. |
| 410 | */ |
| 411 | p2->p_sigacts = sigactsinit(p1, flags & FORK_SHARESIGS); |
| 412 | mutex_enter(p1->p_lock); |
| 413 | p2->p_sflag |= |
| 414 | (p1->p_sflag & (PS_STOPFORK | PS_STOPEXEC | PS_NOCLDSTOP)); |
| 415 | sched_proc_fork(p1, p2); |
| 416 | mutex_exit(p1->p_lock); |
| 417 | |
| 418 | p2->p_stflag = p1->p_stflag; |
| 419 | |
| 420 | /* |
| 421 | * p_stats. |
| 422 | * Copy parts of p_stats, and zero out the rest. |
| 423 | */ |
| 424 | p2->p_stats = pstatscopy(p1->p_stats); |
| 425 | |
| 426 | /* |
| 427 | * Set up the new process address space. |
| 428 | */ |
| 429 | uvm_proc_fork(p1, p2, (flags & FORK_SHAREVM) ? true : false); |
| 430 | |
| 431 | /* |
| 432 | * Finish creating the child process. |
| 433 | * It will return through a different path later. |
| 434 | */ |
| 435 | lwp_create(l1, p2, uaddr, (flags & FORK_PPWAIT) ? LWP_VFORK : 0, |
| 436 | stack, stacksize, (func != NULL) ? func : child_return, arg, &l2, |
| 437 | l1->l_class); |
| 438 | |
| 439 | /* |
| 440 | * Inherit l_private from the parent. |
| 441 | * Note that we cannot use lwp_setprivate() here since that |
| 442 | * also sets the CPU TLS register, which is incorrect if the |
| 443 | * process has changed that without letting the kernel know. |
| 444 | */ |
| 445 | l2->l_private = l1->l_private; |
| 446 | |
| 447 | /* |
| 448 | * If emulation has a process fork hook, call it now. |
| 449 | */ |
| 450 | if (p2->p_emul->e_proc_fork) |
| 451 | (*p2->p_emul->e_proc_fork)(p2, l1, flags); |
| 452 | |
| 453 | /* |
| 454 | * ...and finally, any other random fork hooks that subsystems |
| 455 | * might have registered. |
| 456 | */ |
| 457 | doforkhooks(p2, p1); |
| 458 | |
| 459 | SDT_PROBE(proc, kernel, , create, p2, p1, flags, 0, 0); |
| 460 | |
| 461 | /* |
| 462 | * It's now safe for the scheduler and other processes to see the |
| 463 | * child process. |
| 464 | */ |
| 465 | mutex_enter(proc_lock); |
| 466 | |
| 467 | if (p1->p_session->s_ttyvp != NULL && p1->p_lflag & PL_CONTROLT) |
| 468 | p2->p_lflag |= PL_CONTROLT; |
| 469 | |
| 470 | LIST_INSERT_HEAD(&parent->p_children, p2, p_sibling); |
| 471 | p2->p_exitsig = exitsig; /* signal for parent on exit */ |
| 472 | |
| 473 | /* |
| 474 | * We don't want to tracefork vfork()ed processes because they |
| 475 | * will not receive the SIGTRAP until it is too late. |
| 476 | */ |
| 477 | tracefork = (p1->p_slflag & (PSL_TRACEFORK|PSL_TRACED)) == |
| 478 | (PSL_TRACEFORK|PSL_TRACED) && (flags && FORK_PPWAIT) == 0; |
| 479 | if (tracefork) { |
| 480 | proc_changeparent(p2, p1->p_pptr); |
| 481 | /* |
| 482 | * Set ptrace status. |
| 483 | */ |
| 484 | p1->p_fpid = p2->p_pid; |
| 485 | p2->p_fpid = p1->p_pid; |
| 486 | } |
| 487 | |
| 488 | LIST_INSERT_AFTER(p1, p2, p_pglist); |
| 489 | LIST_INSERT_HEAD(&allproc, p2, p_list); |
| 490 | |
| 491 | p2->p_trace_enabled = trace_is_enabled(p2); |
| 492 | #ifdef __HAVE_SYSCALL_INTERN |
| 493 | (*p2->p_emul->e_syscall_intern)(p2); |
| 494 | #endif |
| 495 | |
| 496 | /* |
| 497 | * Update stats now that we know the fork was successful. |
| 498 | */ |
| 499 | uvmexp.forks++; |
| 500 | if (flags & FORK_PPWAIT) |
| 501 | uvmexp.forks_ppwait++; |
| 502 | if (flags & FORK_SHAREVM) |
| 503 | uvmexp.forks_sharevm++; |
| 504 | |
| 505 | /* |
| 506 | * Pass a pointer to the new process to the caller. |
| 507 | */ |
| 508 | if (rnewprocp != NULL) |
| 509 | *rnewprocp = p2; |
| 510 | |
| 511 | if (ktrpoint(KTR_EMUL)) |
| 512 | p2->p_traceflag |= KTRFAC_TRC_EMUL; |
| 513 | |
| 514 | /* |
| 515 | * Notify any interested parties about the new process. |
| 516 | */ |
| 517 | if (!SLIST_EMPTY(&p1->p_klist)) { |
| 518 | mutex_exit(proc_lock); |
| 519 | KNOTE(&p1->p_klist, NOTE_FORK | p2->p_pid); |
| 520 | mutex_enter(proc_lock); |
| 521 | } |
| 522 | |
| 523 | /* |
| 524 | * Make child runnable, set start time, and add to run queue except |
| 525 | * if the parent requested the child to start in SSTOP state. |
| 526 | */ |
| 527 | mutex_enter(p2->p_lock); |
| 528 | |
| 529 | /* |
| 530 | * Start profiling. |
| 531 | */ |
| 532 | if ((p2->p_stflag & PST_PROFIL) != 0) { |
| 533 | mutex_spin_enter(&p2->p_stmutex); |
| 534 | startprofclock(p2); |
| 535 | mutex_spin_exit(&p2->p_stmutex); |
| 536 | } |
| 537 | |
| 538 | getmicrotime(&p2->p_stats->p_start); |
| 539 | p2->p_acflag = AFORK; |
| 540 | lwp_lock(l2); |
| 541 | KASSERT(p2->p_nrlwps == 1); |
| 542 | if (p2->p_sflag & PS_STOPFORK) { |
| 543 | struct schedstate_percpu *spc = &l2->l_cpu->ci_schedstate; |
| 544 | p2->p_nrlwps = 0; |
| 545 | p2->p_stat = SSTOP; |
| 546 | p2->p_waited = 0; |
| 547 | p1->p_nstopchild++; |
| 548 | l2->l_stat = LSSTOP; |
| 549 | KASSERT(l2->l_wchan == NULL); |
| 550 | lwp_unlock_to(l2, spc->spc_lwplock); |
| 551 | } else { |
| 552 | p2->p_nrlwps = 1; |
| 553 | p2->p_stat = SACTIVE; |
| 554 | l2->l_stat = LSRUN; |
| 555 | sched_enqueue(l2, false); |
| 556 | lwp_unlock(l2); |
| 557 | } |
| 558 | |
| 559 | /* |
| 560 | * Return child pid to parent process, |
| 561 | * marking us as parent via retval[1]. |
| 562 | */ |
| 563 | if (retval != NULL) { |
| 564 | retval[0] = p2->p_pid; |
| 565 | retval[1] = 0; |
| 566 | } |
| 567 | mutex_exit(p2->p_lock); |
| 568 | |
| 569 | /* |
| 570 | * Preserve synchronization semantics of vfork. If waiting for |
| 571 | * child to exec or exit, sleep until it clears LP_VFORKWAIT. |
| 572 | */ |
| 573 | #if 0 |
| 574 | while (l1->l_pflag & LP_VFORKWAIT) { |
| 575 | cv_wait(&l1->l_waitcv, proc_lock); |
| 576 | } |
| 577 | #else |
| 578 | while (p2->p_lflag & PL_PPWAIT) |
| 579 | cv_wait(&p1->p_waitcv, proc_lock); |
| 580 | #endif |
| 581 | |
| 582 | /* |
| 583 | * Let the parent know that we are tracing its child. |
| 584 | */ |
| 585 | if (tracefork) { |
| 586 | ksiginfo_t ksi; |
| 587 | |
| 588 | KSI_INIT_EMPTY(&ksi); |
| 589 | ksi.ksi_signo = SIGTRAP; |
| 590 | ksi.ksi_lid = l1->l_lid; |
| 591 | kpsignal(p1, &ksi, NULL); |
| 592 | } |
| 593 | mutex_exit(proc_lock); |
| 594 | |
| 595 | return 0; |
| 596 | } |
| 597 | |