/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2009 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ /* All Rights Reserved */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int64_t cfork(int, int, int); static int getproc(proc_t **, pid_t, uint_t); #define GETPROC_USER 0x0 #define GETPROC_KERNEL 0x1 static void fork_fail(proc_t *); static void forklwp_fail(proc_t *); int fork_fail_pending; extern struct kmem_cache *process_cache; /* * forkall system call. */ int64_t forkall(void) { return (cfork(0, 0, 0)); } /* * The parent is stopped until the child invokes relvm(). */ int64_t vfork(void) { curthread->t_post_sys = 1; /* so vfwait() will be called */ return (cfork(1, 1, 0)); } /* * fork system call, aka fork1. */ int64_t fork1(void) { return (cfork(0, 1, 0)); } /* * The forkall(), vfork(), and fork1() system calls are no longer * invoked by libc. They are retained only for the benefit of * old statically-linked applications. They should be eliminated * when we no longer care about such old and broken applications. */ /* * forksys system call - forkx, forkallx, vforkx. * This is the interface now invoked by libc. */ int64_t forksys(int subcode, int flags) { switch (subcode) { case 0: return (cfork(0, 1, flags)); /* forkx(flags) */ case 1: return (cfork(0, 0, flags)); /* forkallx(flags) */ case 2: curthread->t_post_sys = 1; /* so vfwait() will be called */ return (cfork(1, 1, flags)); /* vforkx(flags) */ default: return ((int64_t)set_errno(EINVAL)); } } /* ARGSUSED */ static int64_t cfork(int isvfork, int isfork1, int flags) { proc_t *p = ttoproc(curthread); struct as *as; proc_t *cp, **orphpp; klwp_t *clone; kthread_t *t; task_t *tk; rval_t r; int error; int i; rctl_set_t *dup_set; rctl_alloc_gp_t *dup_gp; rctl_entity_p_t e; lwpdir_t *ldp; lwpent_t *lep; lwpent_t *clep; /* * Allow only these two flags. */ if ((flags & ~(FORK_NOSIGCHLD | FORK_WAITPID)) != 0) { error = EINVAL; goto forkerr; } /* * fork is not supported for the /proc agent lwp. */ if (curthread == p->p_agenttp) { error = ENOTSUP; goto forkerr; } if ((error = secpolicy_basic_fork(CRED())) != 0) goto forkerr; /* * If the calling lwp is doing a fork1() then the * other lwps in this process are not duplicated and * don't need to be held where their kernel stacks can be * cloned. If doing forkall(), the process is held with * SHOLDFORK, so that the lwps are at a point where their * stacks can be copied which is on entry or exit from * the kernel. */ if (!holdlwps(isfork1 ? SHOLDFORK1 : SHOLDFORK)) { aston(curthread); error = EINTR; goto forkerr; } #if defined(__sparc) /* * Ensure that the user stack is fully constructed * before creating the child process structure. */ (void) flush_user_windows_to_stack(NULL); #endif mutex_enter(&p->p_lock); /* * If this is vfork(), cancel any suspend request we might * have gotten from some other thread via lwp_suspend(). * Otherwise we could end up with a deadlock on return * from the vfork() in both the parent and the child. */ if (isvfork) curthread->t_proc_flag &= ~TP_HOLDLWP; /* * Prevent our resource set associations from being changed during fork. */ pool_barrier_enter(); mutex_exit(&p->p_lock); /* * Create a child proc struct. Place a VN_HOLD on appropriate vnodes. */ if (getproc(&cp, 0, GETPROC_USER) < 0) { mutex_enter(&p->p_lock); pool_barrier_exit(); continuelwps(p); mutex_exit(&p->p_lock); error = EAGAIN; goto forkerr; } TRACE_2(TR_FAC_PROC, TR_PROC_FORK, "proc_fork:cp %p p %p", cp, p); /* * Assign an address space to child */ if (isvfork) { /* * Clear any watched areas and remember the * watched pages for restoring in vfwait(). */ as = p->p_as; if (avl_numnodes(&as->a_wpage) != 0) { AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER); as_clearwatch(as); p->p_wpage = as->a_wpage; avl_create(&as->a_wpage, wp_compare, sizeof (struct watched_page), offsetof(struct watched_page, wp_link)); AS_LOCK_EXIT(as, &as->a_lock); } cp->p_as = as; cp->p_flag |= SVFORK; } else { /* * We need to hold P_PR_LOCK until the address space has * been duplicated and we've had a chance to remove from the * child any DTrace probes that were in the parent. Holding * P_PR_LOCK prevents any new probes from being added and any * extant probes from being removed. */ mutex_enter(&p->p_lock); sprlock_proc(p); p->p_flag |= SFORKING; mutex_exit(&p->p_lock); error = as_dup(p->p_as, cp); if (error != 0) { mutex_enter(&p->p_lock); sprunlock(p); fork_fail(cp); mutex_enter(&pidlock); orphpp = &p->p_orphan; while (*orphpp != cp) orphpp = &(*orphpp)->p_nextorph; *orphpp = cp->p_nextorph; if (p->p_child == cp) p->p_child = cp->p_sibling; if (cp->p_sibling) cp->p_sibling->p_psibling = cp->p_psibling; if (cp->p_psibling) cp->p_psibling->p_sibling = cp->p_sibling; mutex_enter(&cp->p_lock); tk = cp->p_task; task_detach(cp); ASSERT(cp->p_pool->pool_ref > 0); atomic_add_32(&cp->p_pool->pool_ref, -1); mutex_exit(&cp->p_lock); pid_exit(cp); mutex_exit(&pidlock); task_rele(tk); mutex_enter(&p->p_lock); p->p_flag &= ~SFORKING; pool_barrier_exit(); continuelwps(p); mutex_exit(&p->p_lock); /* * Preserve ENOMEM error condition but * map all others to EAGAIN. */ error = (error == ENOMEM) ? ENOMEM : EAGAIN; goto forkerr; } /* * Remove all DTrace tracepoints from the child process. We * need to do this _before_ duplicating USDT providers since * any associated probes may be immediately enabled. */ if (p->p_dtrace_count > 0) dtrace_fasttrap_fork(p, cp); mutex_enter(&p->p_lock); sprunlock(p); /* Duplicate parent's shared memory */ if (p->p_segacct) shmfork(p, cp); /* * Duplicate any helper actions and providers. The SFORKING * we set above informs the code to enable USDT probes that * sprlock() may fail because the child is being forked. */ if (p->p_dtrace_helpers != NULL) { ASSERT(dtrace_helpers_fork != NULL); (*dtrace_helpers_fork)(p, cp); } mutex_enter(&p->p_lock); p->p_flag &= ~SFORKING; mutex_exit(&p->p_lock); } /* * Duplicate parent's resource controls. */ dup_set = rctl_set_create(); for (;;) { dup_gp = rctl_set_dup_prealloc(p->p_rctls); mutex_enter(&p->p_rctls->rcs_lock); if (rctl_set_dup_ready(p->p_rctls, dup_gp)) break; mutex_exit(&p->p_rctls->rcs_lock); rctl_prealloc_destroy(dup_gp); } e.rcep_p.proc = cp; e.rcep_t = RCENTITY_PROCESS; cp->p_rctls = rctl_set_dup(p->p_rctls, p, cp, &e, dup_set, dup_gp, RCD_DUP | RCD_CALLBACK); mutex_exit(&p->p_rctls->rcs_lock); rctl_prealloc_destroy(dup_gp); /* * Allocate the child's lwp directory and lwpid hash table. */ if (isfork1) cp->p_lwpdir_sz = 2; else cp->p_lwpdir_sz = p->p_lwpdir_sz; cp->p_lwpdir = cp->p_lwpfree = ldp = kmem_zalloc(cp->p_lwpdir_sz * sizeof (lwpdir_t), KM_SLEEP); for (i = 1; i < cp->p_lwpdir_sz; i++, ldp++) ldp->ld_next = ldp + 1; cp->p_tidhash_sz = (cp->p_lwpdir_sz + 2) / 2; cp->p_tidhash = kmem_zalloc(cp->p_tidhash_sz * sizeof (tidhash_t), KM_SLEEP); /* * Duplicate parent's lwps. * Mutual exclusion is not needed because the process is * in the hold state and only the current lwp is running. */ klgrpset_clear(cp->p_lgrpset); if (isfork1) { clone = forklwp(ttolwp(curthread), cp, curthread->t_tid); if (clone == NULL) goto forklwperr; /* * Inherit only the lwp_wait()able flag, * Daemon threads should not call fork1(), but oh well... */ lwptot(clone)->t_proc_flag |= (curthread->t_proc_flag & TP_TWAIT); } else { /* this is forkall(), no one can be in lwp_wait() */ ASSERT(p->p_lwpwait == 0 && p->p_lwpdwait == 0); /* for each entry in the parent's lwp directory... */ for (i = 0, ldp = p->p_lwpdir; i < p->p_lwpdir_sz; i++, ldp++) { klwp_t *clwp; kthread_t *ct; if ((lep = ldp->ld_entry) == NULL) continue; if ((t = lep->le_thread) != NULL) { clwp = forklwp(ttolwp(t), cp, t->t_tid); if (clwp == NULL) goto forklwperr; ct = lwptot(clwp); /* * Inherit lwp_wait()able and daemon flags. */ ct->t_proc_flag |= (t->t_proc_flag & (TP_TWAIT|TP_DAEMON)); /* * Keep track of the clone of curthread to * post return values through lwp_setrval(). * Mark other threads for special treatment * by lwp_rtt() / post_syscall(). */ if (t == curthread) clone = clwp; else ct->t_flag |= T_FORKALL; } else { /* * Replicate zombie lwps in the child. */ clep = kmem_zalloc(sizeof (*clep), KM_SLEEP); clep->le_lwpid = lep->le_lwpid; clep->le_start = lep->le_start; lwp_hash_in(cp, clep, cp->p_tidhash, cp->p_tidhash_sz, 0); } } } /* * Put new process in the parent's process contract, or put it * in a new one if there is an active process template. Send a * fork event (if requested) to whatever contract the child is * a member of. Fails if the parent has been SIGKILLed. */ if (contract_process_fork(NULL, cp, p, B_TRUE) == NULL) goto forklwperr; /* * No fork failures occur beyond this point. */ cp->p_lwpid = p->p_lwpid; if (!isfork1) { cp->p_lwpdaemon = p->p_lwpdaemon; cp->p_zombcnt = p->p_zombcnt; /* * If the parent's lwp ids have wrapped around, so have the * child's. */ cp->p_flag |= p->p_flag & SLWPWRAP; } mutex_enter(&p->p_lock); corectl_path_hold(cp->p_corefile = p->p_corefile); corectl_content_hold(cp->p_content = p->p_content); mutex_exit(&p->p_lock); /* * Duplicate process context ops, if any. */ if (p->p_pctx) forkpctx(p, cp); #ifdef __sparc utrap_dup(p, cp); #endif /* * If the child process has been marked to stop on exit * from this fork, arrange for all other lwps to stop in * sympathy with the active lwp. */ if (PTOU(cp)->u_systrap && prismember(&PTOU(cp)->u_exitmask, curthread->t_sysnum)) { mutex_enter(&cp->p_lock); t = cp->p_tlist; do { t->t_proc_flag |= TP_PRSTOP; aston(t); /* so TP_PRSTOP will be seen */ } while ((t = t->t_forw) != cp->p_tlist); mutex_exit(&cp->p_lock); } /* * If the parent process has been marked to stop on exit * from this fork, and its asynchronous-stop flag has not * been set, arrange for all other lwps to stop before * they return back to user level. */ if (!(p->p_proc_flag & P_PR_ASYNC) && PTOU(p)->u_systrap && prismember(&PTOU(p)->u_exitmask, curthread->t_sysnum)) { mutex_enter(&p->p_lock); t = p->p_tlist; do { t->t_proc_flag |= TP_PRSTOP; aston(t); /* so TP_PRSTOP will be seen */ } while ((t = t->t_forw) != p->p_tlist); mutex_exit(&p->p_lock); } if (PROC_IS_BRANDED(p)) BROP(p)->b_lwp_setrval(clone, p->p_pid, 1); else lwp_setrval(clone, p->p_pid, 1); /* set return values for parent */ r.r_val1 = (int)cp->p_pid; r.r_val2 = 0; /* * pool_barrier_exit() can now be called because the child process has: * - all identifying features cloned or set (p_pid, p_task, p_pool) * - all resource sets associated (p_tlist->*->t_cpupart, p_as->a_mset) * - any other fields set which are used in resource set binding. */ mutex_enter(&p->p_lock); pool_barrier_exit(); mutex_exit(&p->p_lock); mutex_enter(&pidlock); mutex_enter(&cp->p_lock); /* * Set flags telling the child what (not) to do on exit. */ if (flags & FORK_NOSIGCHLD) cp->p_pidflag |= CLDNOSIGCHLD; if (flags & FORK_WAITPID) cp->p_pidflag |= CLDWAITPID; /* * Now that there are lwps and threads attached, add the new * process to the process group. */ pgjoin(cp, p->p_pgidp); cp->p_stat = SRUN; /* * We are now done with all the lwps in the child process. */ t = cp->p_tlist; do { /* * Set the lwp_suspend()ed lwps running. * They will suspend properly at syscall exit. */ if (t->t_proc_flag & TP_HOLDLWP) lwp_create_done(t); else { /* set TS_CREATE to allow continuelwps() to work */ thread_lock(t); ASSERT(t->t_state == TS_STOPPED && !(t->t_schedflag & (TS_CREATE|TS_CSTART))); t->t_schedflag |= TS_CREATE; thread_unlock(t); } } while ((t = t->t_forw) != cp->p_tlist); mutex_exit(&cp->p_lock); if (isvfork) { CPU_STATS_ADDQ(CPU, sys, sysvfork, 1); mutex_enter(&p->p_lock); p->p_flag |= SVFWAIT; curthread->t_flag |= T_VFPARENT; DTRACE_PROC1(create, proc_t *, cp); cv_broadcast(&pr_pid_cv[p->p_slot]); /* inform /proc */ mutex_exit(&p->p_lock); /* * Grab child's p_lock before dropping pidlock to ensure * the process will not disappear before we set it running. */ mutex_enter(&cp->p_lock); mutex_exit(&pidlock); sigdefault(cp); continuelwps(cp); mutex_exit(&cp->p_lock); } else { CPU_STATS_ADDQ(CPU, sys, sysfork, 1); DTRACE_PROC1(create, proc_t *, cp); /* * It is CL_FORKRET's job to drop pidlock. * If we do it here, the process could be set running * and disappear before CL_FORKRET() is called. */ CL_FORKRET(curthread, cp->p_tlist); schedctl_set_cidpri(curthread); ASSERT(MUTEX_NOT_HELD(&pidlock)); } return (r.r_vals); forklwperr: if (isvfork) { if (avl_numnodes(&p->p_wpage) != 0) { /* restore watchpoints to parent */ as = p->p_as; AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER); as->a_wpage = p->p_wpage; avl_create(&p->p_wpage, wp_compare, sizeof (struct watched_page), offsetof(struct watched_page, wp_link)); as_setwatch(as); AS_LOCK_EXIT(as, &as->a_lock); } } else { if (cp->p_segacct) shmexit(cp); as = cp->p_as; cp->p_as = &kas; as_free(as); } if (cp->p_lwpdir) { for (i = 0, ldp = cp->p_lwpdir; i < cp->p_lwpdir_sz; i++, ldp++) if ((lep = ldp->ld_entry) != NULL) kmem_free(lep, sizeof (*lep)); kmem_free(cp->p_lwpdir, cp->p_lwpdir_sz * sizeof (*cp->p_lwpdir)); } cp->p_lwpdir = NULL; cp->p_lwpfree = NULL; cp->p_lwpdir_sz = 0; if (cp->p_tidhash) kmem_free(cp->p_tidhash, cp->p_tidhash_sz * sizeof (*cp->p_tidhash)); cp->p_tidhash = NULL; cp->p_tidhash_sz = 0; forklwp_fail(cp); fork_fail(cp); rctl_set_free(cp->p_rctls); mutex_enter(&pidlock); /* * Detach failed child from task. */ mutex_enter(&cp->p_lock); tk = cp->p_task; task_detach(cp); ASSERT(cp->p_pool->pool_ref > 0); atomic_add_32(&cp->p_pool->pool_ref, -1); mutex_exit(&cp->p_lock); orphpp = &p->p_orphan; while (*orphpp != cp) orphpp = &(*orphpp)->p_nextorph; *orphpp = cp->p_nextorph; if (p->p_child == cp) p->p_child = cp->p_sibling; if (cp->p_sibling) cp->p_sibling->p_psibling = cp->p_psibling; if (cp->p_psibling) cp->p_psibling->p_sibling = cp->p_sibling; pid_exit(cp); mutex_exit(&pidlock); task_rele(tk); mutex_enter(&p->p_lock); pool_barrier_exit(); continuelwps(p); mutex_exit(&p->p_lock); error = EAGAIN; forkerr: return ((int64_t)set_errno(error)); } /* * Free allocated resources from getproc() if a fork failed. */ static void fork_fail(proc_t *cp) { uf_info_t *fip = P_FINFO(cp); fcnt_add(fip, -1); sigdelq(cp, NULL, 0); mutex_enter(&pidlock); upcount_dec(crgetruid(cp->p_cred), crgetzoneid(cp->p_cred)); mutex_exit(&pidlock); /* * single threaded, so no locking needed here */ crfree(cp->p_cred); kmem_free(fip->fi_list, fip->fi_nfiles * sizeof (uf_entry_t)); VN_RELE(PTOU(curproc)->u_cdir); if (PTOU(curproc)->u_rdir) VN_RELE(PTOU(curproc)->u_rdir); if (cp->p_exec) VN_RELE(cp->p_exec); if (cp->p_execdir) VN_RELE(cp->p_execdir); if (PTOU(curproc)->u_cwd) refstr_rele(PTOU(curproc)->u_cwd); } /* * Clean up the lwps already created for this child process. * The fork failed while duplicating all the lwps of the parent * and those lwps already created must be freed. * This process is invisible to the rest of the system, * so we don't need to hold p->p_lock to protect the list. */ static void forklwp_fail(proc_t *p) { kthread_t *t; task_t *tk; while ((t = p->p_tlist) != NULL) { /* * First remove the lwp from the process's p_tlist. */ if (t != t->t_forw) p->p_tlist = t->t_forw; else p->p_tlist = NULL; p->p_lwpcnt--; t->t_forw->t_back = t->t_back; t->t_back->t_forw = t->t_forw; tk = p->p_task; mutex_enter(&p->p_zone->zone_nlwps_lock); tk->tk_nlwps--; tk->tk_proj->kpj_nlwps--; p->p_zone->zone_nlwps--; mutex_exit(&p->p_zone->zone_nlwps_lock); ASSERT(t->t_schedctl == NULL); if (t->t_door != NULL) { kmem_free(t->t_door, sizeof (door_data_t)); t->t_door = NULL; } lwp_ctmpl_clear(ttolwp(t)); /* * Remove the thread from the all threads list. * We need to hold pidlock for this. */ mutex_enter(&pidlock); t->t_next->t_prev = t->t_prev; t->t_prev->t_next = t->t_next; CL_EXIT(t); /* tell the scheduler that we're exiting */ cv_broadcast(&t->t_joincv); /* tell anyone in thread_join */ mutex_exit(&pidlock); /* * Let the lgroup load averages know that this thread isn't * going to show up (i.e. un-do what was done on behalf of * this thread by the earlier lgrp_move_thread()). */ kpreempt_disable(); lgrp_move_thread(t, NULL, 1); kpreempt_enable(); /* * The thread was created TS_STOPPED. * We change it to TS_FREE to avoid an * ASSERT() panic in thread_free(). */ t->t_state = TS_FREE; thread_rele(t); thread_free(t); } } extern struct as kas; /* * fork a kernel process. */ int newproc(void (*pc)(), caddr_t arg, id_t cid, int pri, struct contract **ct, pid_t pid) { proc_t *p; struct user *up; kthread_t *t; cont_process_t *ctp = NULL; rctl_entity_p_t e; ASSERT(cid != sysdccid); ASSERT(cid != syscid || ct == NULL); if (CLASS_KERNEL(cid)) { rctl_alloc_gp_t *init_gp; rctl_set_t *init_set; ASSERT(pid != 1); if (getproc(&p, pid, GETPROC_KERNEL) < 0) return (EAGAIN); /* * Release the hold on the p_exec and p_execdir, these * were acquired in getproc() */ if (p->p_execdir != NULL) VN_RELE(p->p_execdir); if (p->p_exec != NULL) VN_RELE(p->p_exec); p->p_flag |= SNOWAIT; p->p_exec = NULL; p->p_execdir = NULL; init_set = rctl_set_create(); init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS); /* * kernel processes do not inherit /proc tracing flags. */ sigemptyset(&p->p_sigmask); premptyset(&p->p_fltmask); up = PTOU(p); up->u_systrap = 0; premptyset(&(up->u_entrymask)); premptyset(&(up->u_exitmask)); mutex_enter(&p->p_lock); e.rcep_p.proc = p; e.rcep_t = RCENTITY_PROCESS; p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set, init_gp); mutex_exit(&p->p_lock); rctl_prealloc_destroy(init_gp); t = lwp_kernel_create(p, pc, arg, TS_STOPPED, pri); } else { rctl_alloc_gp_t *init_gp, *default_gp; rctl_set_t *init_set; task_t *tk, *tk_old; klwp_t *lwp; ASSERT(pid == 1); if (getproc(&p, pid, GETPROC_USER) < 0) return (EAGAIN); /* * init creates a new task, distinct from the task * containing kernel "processes". */ tk = task_create(0, p->p_zone); mutex_enter(&tk->tk_zone->zone_nlwps_lock); tk->tk_proj->kpj_ntasks++; mutex_exit(&tk->tk_zone->zone_nlwps_lock); default_gp = rctl_rlimit_set_prealloc(RLIM_NLIMITS); init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS); init_set = rctl_set_create(); mutex_enter(&pidlock); mutex_enter(&p->p_lock); tk_old = p->p_task; /* switch to new task */ task_detach(p); task_begin(tk, p); mutex_exit(&pidlock); e.rcep_p.proc = p; e.rcep_t = RCENTITY_PROCESS; p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set, init_gp); rctlproc_default_init(p, default_gp); mutex_exit(&p->p_lock); task_rele(tk_old); rctl_prealloc_destroy(default_gp); rctl_prealloc_destroy(init_gp); if ((lwp = lwp_create(pc, arg, 0, p, TS_STOPPED, pri, &curthread->t_hold, cid, 1)) == NULL) { task_t *tk; fork_fail(p); mutex_enter(&pidlock); mutex_enter(&p->p_lock); tk = p->p_task; task_detach(p); ASSERT(p->p_pool->pool_ref > 0); atomic_add_32(&p->p_pool->pool_ref, -1); mutex_exit(&p->p_lock); pid_exit(p); mutex_exit(&pidlock); task_rele(tk); return (EAGAIN); } t = lwptot(lwp); ctp = contract_process_fork(sys_process_tmpl, p, curproc, B_FALSE); ASSERT(ctp != NULL); if (ct != NULL) *ct = &ctp->conp_contract; } ASSERT3U(t->t_tid, ==, 1); p->p_lwpid = 1; mutex_enter(&pidlock); pgjoin(p, p->p_parent->p_pgidp); p->p_stat = SRUN; mutex_enter(&p->p_lock); t->t_proc_flag &= ~TP_HOLDLWP; lwp_create_done(t); mutex_exit(&p->p_lock); mutex_exit(&pidlock); return (0); } /* * create a child proc struct. */ static int getproc(proc_t **cpp, pid_t pid, uint_t flags) { proc_t *pp, *cp; pid_t newpid; struct user *uarea; extern uint_t nproc; struct cred *cr; uid_t ruid; zoneid_t zoneid; if (!page_mem_avail(tune.t_minarmem)) return (-1); if (zone_status_get(curproc->p_zone) >= ZONE_IS_SHUTTING_DOWN) return (-1); /* no point in starting new processes */ pp = (flags & GETPROC_KERNEL) ? &p0 : curproc; cp = kmem_cache_alloc(process_cache, KM_SLEEP); bzero(cp, sizeof (proc_t)); /* * Make proc entry for child process */ mutex_init(&cp->p_splock, NULL, MUTEX_DEFAULT, NULL); mutex_init(&cp->p_crlock, NULL, MUTEX_DEFAULT, NULL); mutex_init(&cp->p_pflock, NULL, MUTEX_DEFAULT, NULL); #if defined(__x86) mutex_init(&cp->p_ldtlock, NULL, MUTEX_DEFAULT, NULL); #endif mutex_init(&cp->p_maplock, NULL, MUTEX_DEFAULT, NULL); cp->p_stat = SIDL; cp->p_mstart = gethrtime(); cp->p_as = &kas; /* * p_zone must be set before we call pid_allocate since the process * will be visible after that and code such as prfind_zone will * look at the p_zone field. */ cp->p_zone = pp->p_zone; cp->p_t1_lgrpid = LGRP_NONE; cp->p_tr_lgrpid = LGRP_NONE; if ((newpid = pid_allocate(cp, pid, PID_ALLOC_PROC)) == -1) { if (nproc == v.v_proc) { CPU_STATS_ADDQ(CPU, sys, procovf, 1); cmn_err(CE_WARN, "out of processes"); } goto bad; } /* * If not privileged make sure that this user hasn't exceeded * v.v_maxup processes, and that users collectively haven't * exceeded v.v_maxupttl processes. */ mutex_enter(&pidlock); ASSERT(nproc < v.v_proc); /* otherwise how'd we get our pid? */ cr = CRED(); ruid = crgetruid(cr); zoneid = crgetzoneid(cr); if (nproc >= v.v_maxup && /* short-circuit; usually false */ (nproc >= v.v_maxupttl || upcount_get(ruid, zoneid) >= v.v_maxup) && secpolicy_newproc(cr) != 0) { mutex_exit(&pidlock); zcmn_err(zoneid, CE_NOTE, "out of per-user processes for uid %d", ruid); goto bad; } /* * Everything is cool, put the new proc on the active process list. * It is already on the pid list and in /proc. * Increment the per uid process count (upcount). */ nproc++; upcount_inc(ruid, zoneid); cp->p_next = practive; practive->p_prev = cp; practive = cp; cp->p_ignore = pp->p_ignore; cp->p_siginfo = pp->p_siginfo; cp->p_flag = pp->p_flag & (SJCTL|SNOWAIT|SNOCD); cp->p_sessp = pp->p_sessp; sess_hold(pp); cp->p_exec = pp->p_exec; cp->p_execdir = pp->p_execdir; cp->p_brand = pp->p_brand; if (PROC_IS_BRANDED(pp)) BROP(pp)->b_copy_procdata(cp, pp); cp->p_bssbase = pp->p_bssbase; cp->p_brkbase = pp->p_brkbase; cp->p_brksize = pp->p_brksize; cp->p_brkpageszc = pp->p_brkpageszc; cp->p_stksize = pp->p_stksize; cp->p_stkpageszc = pp->p_stkpageszc; cp->p_stkprot = pp->p_stkprot; cp->p_datprot = pp->p_datprot; cp->p_usrstack = pp->p_usrstack; cp->p_model = pp->p_model; cp->p_ppid = pp->p_pid; cp->p_ancpid = pp->p_pid; cp->p_portcnt = pp->p_portcnt; /* * Initialize watchpoint structures */ avl_create(&cp->p_warea, wa_compare, sizeof (struct watched_area), offsetof(struct watched_area, wa_link)); /* * Initialize immediate resource control values. */ cp->p_stk_ctl = pp->p_stk_ctl; cp->p_fsz_ctl = pp->p_fsz_ctl; cp->p_vmem_ctl = pp->p_vmem_ctl; cp->p_fno_ctl = pp->p_fno_ctl; /* * Link up to parent-child-sibling chain. No need to lock * in general since only a call to freeproc() (done by the * same parent as newproc()) diddles with the child chain. */ cp->p_sibling = pp->p_child; if (pp->p_child) pp->p_child->p_psibling = cp; cp->p_parent = pp; pp->p_child = cp; cp->p_child_ns = NULL; cp->p_sibling_ns = NULL; cp->p_nextorph = pp->p_orphan; cp->p_nextofkin = pp; pp->p_orphan = cp; /* * Inherit profiling state; do not inherit REALPROF profiling state. */ cp->p_prof = pp->p_prof; cp->p_rprof_cyclic = CYCLIC_NONE; /* * Inherit pool pointer from the parent. Kernel processes are * always bound to the default pool. */ mutex_enter(&pp->p_lock); if (flags & GETPROC_KERNEL) { cp->p_pool = pool_default; cp->p_flag |= SSYS; } else { cp->p_pool = pp->p_pool; } atomic_add_32(&cp->p_pool->pool_ref, 1); mutex_exit(&pp->p_lock); /* * Add the child process to the current task. Kernel processes * are always attached to task0. */ mutex_enter(&cp->p_lock); if (flags & GETPROC_KERNEL) task_attach(task0p, cp); else task_attach(pp->p_task, cp); mutex_exit(&cp->p_lock); mutex_exit(&pidlock); avl_create(&cp->p_ct_held, contract_compar, sizeof (contract_t), offsetof(contract_t, ct_ctlist)); /* * Duplicate any audit information kept in the process table */ if (audit_active) /* copy audit data to cp */ audit_newproc(cp); crhold(cp->p_cred = cr); /* * Bump up the counts on the file structures pointed at by the * parent's file table since the child will point at them too. */ fcnt_add(P_FINFO(pp), 1); if (PTOU(pp)->u_cdir) { VN_HOLD(PTOU(pp)->u_cdir); } else { ASSERT(pp == &p0); /* * We must be at or before vfs_mountroot(); it will take care of * assigning our current directory. */ } if (PTOU(pp)->u_rdir) VN_HOLD(PTOU(pp)->u_rdir); if (PTOU(pp)->u_cwd) refstr_hold(PTOU(pp)->u_cwd); /* * copy the parent's uarea. */ uarea = PTOU(cp); bcopy(PTOU(pp), uarea, sizeof (*uarea)); flist_fork(P_FINFO(pp), P_FINFO(cp)); gethrestime(&uarea->u_start); uarea->u_ticks = ddi_get_lbolt(); uarea->u_mem = rm_asrss(pp->p_as); uarea->u_acflag = AFORK; /* * If inherit-on-fork, copy /proc tracing flags to child. */ if ((pp->p_proc_flag & P_PR_FORK) != 0) { cp->p_proc_flag |= pp->p_proc_flag & (P_PR_TRACE|P_PR_FORK); cp->p_sigmask = pp->p_sigmask; cp->p_fltmask = pp->p_fltmask; } else { sigemptyset(&cp->p_sigmask); premptyset(&cp->p_fltmask); uarea->u_systrap = 0; premptyset(&uarea->u_entrymask); premptyset(&uarea->u_exitmask); } /* * If microstate accounting is being inherited, mark child */ if ((pp->p_flag & SMSFORK) != 0) cp->p_flag |= pp->p_flag & (SMSFORK|SMSACCT); /* * Inherit fixalignment flag from the parent */ cp->p_fixalignment = pp->p_fixalignment; if (cp->p_exec) VN_HOLD(cp->p_exec); if (cp->p_execdir) VN_HOLD(cp->p_execdir); *cpp = cp; return (0); bad: ASSERT(MUTEX_NOT_HELD(&pidlock)); mutex_destroy(&cp->p_crlock); mutex_destroy(&cp->p_pflock); #if defined(__x86) mutex_destroy(&cp->p_ldtlock); #endif if (newpid != -1) { proc_entry_free(cp->p_pidp); (void) pid_rele(cp->p_pidp); } kmem_cache_free(process_cache, cp); /* * We most likely got into this situation because some process is * forking out of control. As punishment, put it to sleep for a * bit so it can't eat the machine alive. Sleep interval is chosen * to allow no more than one fork failure per cpu per clock tick * on average (yes, I just made this up). This has two desirable * properties: (1) it sets a constant limit on the fork failure * rate, and (2) the busier the system is, the harsher the penalty * for abusing it becomes. */ INCR_COUNT(&fork_fail_pending, &pidlock); delay(fork_fail_pending / ncpus + 1); DECR_COUNT(&fork_fail_pending, &pidlock); return (-1); /* out of memory or proc slots */ } /* * Release virtual memory. * In the case of vfork(), the child was given exclusive access to its * parent's address space. The parent is waiting in vfwait() for the * child to release its exclusive claim via relvm(). */ void relvm() { proc_t *p = curproc; ASSERT((unsigned)p->p_lwpcnt <= 1); prrelvm(); /* inform /proc */ if (p->p_flag & SVFORK) { proc_t *pp = p->p_parent; /* * The child process is either exec'ing or exit'ing. * The child is now separated from the parent's address * space. The parent process is made dispatchable. * * This is a delicate locking maneuver, involving * both the parent's p_lock and the child's p_lock. * As soon as the SVFORK flag is turned off, the * parent is free to run, but it must not run until * we wake it up using its p_cv because it might * exit and we would be referencing invalid memory. * Therefore, we hold the parent with its p_lock * while protecting our p_flags with our own p_lock. */ try_again: mutex_enter(&p->p_lock); /* grab child's lock first */ prbarrier(p); /* make sure /proc is blocked out */ mutex_enter(&pp->p_lock); /* * Check if parent is locked by /proc. */ if (pp->p_proc_flag & P_PR_LOCK) { /* * Delay until /proc is done with the parent. * We must drop our (the child's) p->p_lock, wait * via prbarrier() on the parent, then start over. */ mutex_exit(&p->p_lock); prbarrier(pp); mutex_exit(&pp->p_lock); goto try_again; } p->p_flag &= ~SVFORK; kpreempt_disable(); p->p_as = &kas; /* * notify hat of change in thread's address space */ hat_thread_exit(curthread); kpreempt_enable(); /* * child sizes are copied back to parent because * child may have grown. */ pp->p_brkbase = p->p_brkbase; pp->p_brksize = p->p_brksize; pp->p_stksize = p->p_stksize; /* * The parent is no longer waiting for the vfork()d child. * Restore the parent's watched pages, if any. This is * safe because we know the parent is not locked by /proc */ pp->p_flag &= ~SVFWAIT; if (avl_numnodes(&pp->p_wpage) != 0) { pp->p_as->a_wpage = pp->p_wpage; avl_create(&pp->p_wpage, wp_compare, sizeof (struct watched_page), offsetof(struct watched_page, wp_link)); } cv_signal(&pp->p_cv); mutex_exit(&pp->p_lock); mutex_exit(&p->p_lock); } else { if (p->p_as != &kas) { struct as *as; if (p->p_segacct) shmexit(p); /* * We grab p_lock for the benefit of /proc */ kpreempt_disable(); mutex_enter(&p->p_lock); prbarrier(p); /* make sure /proc is blocked out */ as = p->p_as; p->p_as = &kas; mutex_exit(&p->p_lock); /* * notify hat of change in thread's address space */ hat_thread_exit(curthread); kpreempt_enable(); as_free(as); p->p_tr_lgrpid = LGRP_NONE; } } } /* * Wait for child to exec or exit. * Called by parent of vfork'ed process. * See important comments in relvm(), above. */ void vfwait(pid_t pid) { int signalled = 0; proc_t *pp = ttoproc(curthread); proc_t *cp; /* * Wait for child to exec or exit. */ for (;;) { mutex_enter(&pidlock); cp = prfind(pid); if (cp == NULL || cp->p_parent != pp) { /* * Child has exit()ed. */ mutex_exit(&pidlock); break; } /* * Grab the child's p_lock before releasing pidlock. * Otherwise, the child could exit and we would be * referencing invalid memory. */ mutex_enter(&cp->p_lock); mutex_exit(&pidlock); if (!(cp->p_flag & SVFORK)) { /* * Child has exec()ed or is exit()ing. */ mutex_exit(&cp->p_lock); break; } mutex_enter(&pp->p_lock); mutex_exit(&cp->p_lock); /* * We might be waked up spuriously from the cv_wait(). * We have to do the whole operation over again to be * sure the child's SVFORK flag really is turned off. * We cannot make reference to the child because it can * exit before we return and we would be referencing * invalid memory. * * Because this is potentially a very long-term wait, * we call cv_wait_sig() (for its jobcontrol and /proc * side-effects) unless there is a current signal, in * which case we use cv_wait() because we cannot return * from this function until the child has released the * address space. Calling cv_wait_sig() with a current * signal would lead to an indefinite loop here because * cv_wait_sig() returns immediately in this case. */ if (signalled) cv_wait(&pp->p_cv, &pp->p_lock); else signalled = !cv_wait_sig(&pp->p_cv, &pp->p_lock); mutex_exit(&pp->p_lock); } /* restore watchpoints to parent */ if (pr_watch_active(pp)) { struct as *as = pp->p_as; AS_LOCK_ENTER(as, &as->a_lock, RW_WRITER); as_setwatch(as); AS_LOCK_EXIT(as, &as->a_lock); } mutex_enter(&pp->p_lock); prbarrier(pp); /* barrier against /proc locking */ continuelwps(pp); mutex_exit(&pp->p_lock); }