1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 #include <sys/param.h> 32 #include <sys/types.h> 33 #include <sys/sysmacros.h> 34 #include <sys/systm.h> 35 #include <sys/errno.h> 36 #include <sys/syscall.h> 37 #include <sys/proc.h> 38 #include <sys/processor.h> 39 #include <sys/fault.h> 40 #include <sys/ucontext.h> 41 #include <sys/signal.h> 42 #include <sys/unistd.h> 43 #include <sys/procfs.h> 44 #include <sys/prsystm.h> 45 #include <sys/cmn_err.h> 46 #include <sys/debug.h> 47 #include <sys/klwp.h> 48 #include <sys/pool.h> 49 50 /* 51 * System call to create an lwp. 52 * 53 * Notes on the LWP_DETACHED and LWP_DAEMON flags: 54 * 55 * A detached lwp (LWP_DETACHED) cannot be the specific target of 56 * lwp_wait() (it is not joinable), but lwp_wait(0, ...) is required 57 * to sleep until all non-daemon detached lwps have terminated before 58 * returning EDEADLK because a detached lwp might create a non-detached lwp 59 * that could then be returned by lwp_wait(0, ...). See also lwp_detach(). 60 * 61 * A daemon lwp (LWP_DAEMON) is a detached lwp that has the additional 62 * property that it does not affect the termination condition of the 63 * process: The last non-daemon lwp to call lwp_exit() causes the process 64 * to exit and lwp_wait(0, ...) does not sleep waiting for daemon lwps 65 * to terminate. See the block comment before lwp_wait(). 66 */ 67 int 68 syslwp_create(ucontext_t *ucp, int flags, id_t *new_lwp) 69 { 70 klwp_t *lwp; 71 proc_t *p = ttoproc(curthread); 72 kthread_t *t; 73 ucontext_t uc; 74 #ifdef _SYSCALL32_IMPL 75 ucontext32_t uc32; 76 #endif /* _SYSCALL32_IMPL */ 77 k_sigset_t sigmask; 78 int tid; 79 model_t model = get_udatamodel(); 80 uintptr_t thrptr = 0; 81 82 if (flags & ~(LWP_DAEMON|LWP_DETACHED|LWP_SUSPENDED)) 83 return (set_errno(EINVAL)); 84 85 /* 86 * lwp_create() is disallowed for the /proc agent lwp. 87 */ 88 if (curthread == p->p_agenttp) 89 return (set_errno(ENOTSUP)); 90 91 if (model == DATAMODEL_NATIVE) { 92 if (copyin(ucp, &uc, sizeof (ucontext_t))) 93 return (set_errno(EFAULT)); 94 sigutok(&uc.uc_sigmask, &sigmask); 95 #if defined(__i386) 96 /* 97 * libc stashed thrptr into unused kernel %sp. 98 * See setup_context() in libc. 99 */ 100 thrptr = (uint32_t)uc.uc_mcontext.gregs[ESP]; 101 #endif 102 } 103 #ifdef _SYSCALL32_IMPL 104 else { 105 if (copyin(ucp, &uc32, sizeof (ucontext32_t))) 106 return (set_errno(EFAULT)); 107 sigutok(&uc32.uc_sigmask, &sigmask); 108 #if defined(__sparc) 109 ucontext_32ton(&uc32, &uc, NULL, NULL); 110 #else /* __amd64 */ 111 ucontext_32ton(&uc32, &uc); 112 /* 113 * libc stashed thrptr into unused kernel %sp. 114 * See setup_context() in libc. 115 */ 116 thrptr = (uint32_t)uc32.uc_mcontext.gregs[ESP]; 117 #endif 118 } 119 #endif /* _SYSCALL32_IMPL */ 120 121 (void) save_syscall_args(); /* save args for tracing first */ 122 123 mutex_enter(&curproc->p_lock); 124 pool_barrier_enter(); 125 mutex_exit(&curproc->p_lock); 126 lwp = lwp_create(lwp_rtt, NULL, NULL, curproc, TS_STOPPED, 127 curthread->t_pri, &sigmask, curthread->t_cid, 0); 128 mutex_enter(&curproc->p_lock); 129 pool_barrier_exit(); 130 mutex_exit(&curproc->p_lock); 131 if (lwp == NULL) 132 return (set_errno(EAGAIN)); 133 134 lwp_load(lwp, uc.uc_mcontext.gregs, thrptr); 135 136 t = lwptot(lwp); 137 /* 138 * Copy the new lwp's lwpid into the caller's specified buffer. 139 */ 140 if (new_lwp && copyout(&t->t_tid, new_lwp, sizeof (id_t))) { 141 /* 142 * caller's buffer is not writable, return 143 * EFAULT, and terminate new lwp. 144 */ 145 mutex_enter(&p->p_lock); 146 t->t_proc_flag |= TP_EXITLWP; 147 t->t_sig_check = 1; 148 t->t_sysnum = 0; 149 t->t_proc_flag &= ~TP_HOLDLWP; 150 lwp_create_done(t); 151 mutex_exit(&p->p_lock); 152 return (set_errno(EFAULT)); 153 } 154 155 /* 156 * clone callers context, if any. must be invoked 157 * while -not- holding p_lock. 158 */ 159 if (curthread->t_ctx) 160 lwp_createctx(curthread, t); 161 162 /* 163 * copy current contract templates 164 */ 165 lwp_ctmpl_copy(lwp, ttolwp(curthread)); 166 167 mutex_enter(&p->p_lock); 168 /* 169 * Copy the syscall arguments to the new lwp's arg area 170 * for the benefit of debuggers. 171 */ 172 t->t_sysnum = SYS_lwp_create; 173 lwp->lwp_ap = lwp->lwp_arg; 174 lwp->lwp_arg[0] = (long)ucp; 175 lwp->lwp_arg[1] = (long)flags; 176 lwp->lwp_arg[2] = (long)new_lwp; 177 lwp->lwp_argsaved = 1; 178 179 if (!(flags & (LWP_DETACHED|LWP_DAEMON))) 180 t->t_proc_flag |= TP_TWAIT; 181 if (flags & LWP_DAEMON) { 182 t->t_proc_flag |= TP_DAEMON; 183 p->p_lwpdaemon++; 184 } 185 186 tid = (int)t->t_tid; /* for /proc debuggers */ 187 188 /* 189 * We now set the newly-created lwp running. 190 * If it is being created as LWP_SUSPENDED, we leave its 191 * TP_HOLDLWP flag set so it will stop in system call exit. 192 */ 193 if (!(flags & LWP_SUSPENDED)) 194 t->t_proc_flag &= ~TP_HOLDLWP; 195 lwp_create_done(t); 196 mutex_exit(&p->p_lock); 197 198 return (tid); 199 } 200 201 /* 202 * Exit the calling lwp 203 */ 204 void 205 syslwp_exit() 206 { 207 proc_t *p = ttoproc(curthread); 208 209 mutex_enter(&p->p_lock); 210 lwp_exit(); 211 /* NOTREACHED */ 212 } 213