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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2009 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 #include <sys/param.h>
30 #include <sys/types.h>
31 #include <sys/sysmacros.h>
32 #include <sys/systm.h>
33 #include <sys/errno.h>
34 #include <sys/syscall.h>
35 #include <sys/proc.h>
36 #include <sys/processor.h>
37 #include <sys/fault.h>
38 #include <sys/ucontext.h>
39 #include <sys/signal.h>
40 #include <sys/unistd.h>
41 #include <sys/procfs.h>
42 #include <sys/prsystm.h>
43 #include <sys/cmn_err.h>
44 #include <sys/debug.h>
45 #include <sys/klwp.h>
46 #include <sys/pool.h>
47
48 /*
49 * System call to create an lwp.
50 *
51 * Notes on the LWP_DETACHED and LWP_DAEMON flags:
52 *
53 * A detached lwp (LWP_DETACHED) cannot be the specific target of
54 * lwp_wait() (it is not joinable), but lwp_wait(0, ...) is required
55 * to sleep until all non-daemon detached lwps have terminated before
56 * returning EDEADLK because a detached lwp might create a non-detached lwp
57 * that could then be returned by lwp_wait(0, ...). See also lwp_detach().
58 *
59 * A daemon lwp (LWP_DAEMON) is a detached lwp that has the additional
60 * property that it does not affect the termination condition of the
61 * process: The last non-daemon lwp to call lwp_exit() causes the process
62 * to exit and lwp_wait(0, ...) does not sleep waiting for daemon lwps
63 * to terminate. See the block comment before lwp_wait().
64 */
65 int
syslwp_create(ucontext_t * ucp,int flags,id_t * new_lwp)66 syslwp_create(ucontext_t *ucp, int flags, id_t *new_lwp)
67 {
68 klwp_t *lwp;
69 proc_t *p = ttoproc(curthread);
70 kthread_t *t;
71 ucontext_t uc;
72 #ifdef _SYSCALL32_IMPL
73 ucontext32_t uc32;
74 #endif /* _SYSCALL32_IMPL */
75 k_sigset_t sigmask;
76 int tid;
77 model_t model = get_udatamodel();
78 uintptr_t thrptr = 0;
79
80 if (flags & ~(LWP_DAEMON|LWP_DETACHED|LWP_SUSPENDED))
81 return (set_errno(EINVAL));
82
83 /*
84 * lwp_create() is disallowed for the /proc agent lwp.
85 */
86 if (curthread == p->p_agenttp)
87 return (set_errno(ENOTSUP));
88
89 if (model == DATAMODEL_NATIVE) {
90 if (copyin(ucp, &uc, sizeof (ucontext_t)))
91 return (set_errno(EFAULT));
92 sigutok(&uc.uc_sigmask, &sigmask);
93 }
94 #ifdef _SYSCALL32_IMPL
95 else {
96 if (copyin(ucp, &uc32, sizeof (ucontext32_t)))
97 return (set_errno(EFAULT));
98 sigutok(&uc32.uc_sigmask, &sigmask);
99 #if defined(__sparc)
100 ucontext_32ton(&uc32, &uc, NULL, NULL);
101 #else /* __amd64 */
102 ucontext_32ton(&uc32, &uc);
103 /*
104 * libc stashed thrptr into unused kernel %sp.
105 * See setup_context() in libc.
106 */
107 thrptr = (uint32_t)uc32.uc_mcontext.gregs[ESP];
108 #endif
109 }
110 #endif /* _SYSCALL32_IMPL */
111
112 /*
113 * Tell machine specific code that we are creating a new lwp
114 */
115 LWP_MMODEL_NEWLWP();
116
117 (void) save_syscall_args(); /* save args for tracing first */
118
119 mutex_enter(&curproc->p_lock);
120 pool_barrier_enter();
121 mutex_exit(&curproc->p_lock);
122 lwp = lwp_create(lwp_rtt, NULL, 0, curproc, TS_STOPPED,
123 curthread->t_pri, &sigmask, curthread->t_cid, 0);
124 mutex_enter(&curproc->p_lock);
125 pool_barrier_exit();
126 mutex_exit(&curproc->p_lock);
127 if (lwp == NULL)
128 return (set_errno(EAGAIN));
129
130 lwp_load(lwp, uc.uc_mcontext.gregs, thrptr);
131
132 t = lwptot(lwp);
133 /*
134 * Copy the new lwp's lwpid into the caller's specified buffer.
135 */
136 if (new_lwp && copyout(&t->t_tid, new_lwp, sizeof (id_t))) {
137 /*
138 * caller's buffer is not writable, return
139 * EFAULT, and terminate new lwp.
140 */
141 mutex_enter(&p->p_lock);
142 t->t_proc_flag |= TP_EXITLWP;
143 t->t_sig_check = 1;
144 t->t_sysnum = 0;
145 t->t_proc_flag &= ~TP_HOLDLWP;
146 lwp_create_done(t);
147 mutex_exit(&p->p_lock);
148 return (set_errno(EFAULT));
149 }
150
151 /*
152 * clone callers context, if any. must be invoked
153 * while -not- holding p_lock.
154 */
155 if (curthread->t_ctx)
156 lwp_createctx(curthread, t);
157
158 /*
159 * copy current contract templates
160 */
161 lwp_ctmpl_copy(lwp, ttolwp(curthread));
162
163 mutex_enter(&p->p_lock);
164 /*
165 * Copy the syscall arguments to the new lwp's arg area
166 * for the benefit of debuggers.
167 */
168 t->t_sysnum = SYS_lwp_create;
169 lwp->lwp_ap = lwp->lwp_arg;
170 lwp->lwp_arg[0] = (long)ucp;
171 lwp->lwp_arg[1] = (long)flags;
172 lwp->lwp_arg[2] = (long)new_lwp;
173 lwp->lwp_argsaved = 1;
174
175 if (!(flags & (LWP_DETACHED|LWP_DAEMON)))
176 t->t_proc_flag |= TP_TWAIT;
177 if (flags & LWP_DAEMON) {
178 t->t_proc_flag |= TP_DAEMON;
179 p->p_lwpdaemon++;
180 }
181
182 tid = (int)t->t_tid; /* for /proc debuggers */
183
184 /*
185 * We now set the newly-created lwp running.
186 * If it is being created as LWP_SUSPENDED, we leave its
187 * TP_HOLDLWP flag set so it will stop in system call exit.
188 */
189 if (!(flags & LWP_SUSPENDED))
190 t->t_proc_flag &= ~TP_HOLDLWP;
191 lwp_create_done(t);
192 mutex_exit(&p->p_lock);
193
194 return (tid);
195 }
196
197 /*
198 * Exit the calling lwp
199 */
200 void
syslwp_exit()201 syslwp_exit()
202 {
203 proc_t *p = ttoproc(curthread);
204
205 mutex_enter(&p->p_lock);
206 lwp_exit();
207 /* NOTREACHED */
208 }
209