1 /* 2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/kthread.h> 32 #include <sys/lock.h> 33 #include <sys/mutex.h> 34 #include <sys/proc.h> 35 #include <sys/resourcevar.h> 36 #include <sys/signalvar.h> 37 #include <sys/sx.h> 38 #include <sys/unistd.h> 39 #include <sys/wait.h> 40 41 #include <machine/stdarg.h> 42 43 /* 44 * Start a kernel process. This is called after a fork() call in 45 * mi_startup() in the file kern/init_main.c. 46 * 47 * This function is used to start "internal" daemons and intended 48 * to be called from SYSINIT(). 49 */ 50 void 51 kproc_start(udata) 52 const void *udata; 53 { 54 const struct kproc_desc *kp = udata; 55 int error; 56 57 error = kthread_create((void (*)(void *))kp->func, NULL, 58 kp->global_procpp, 0, "%s", kp->arg0); 59 if (error) 60 panic("kproc_start: %s: error %d", kp->arg0, error); 61 } 62 63 /* 64 * Create a kernel process/thread/whatever. It shares its address space 65 * with proc0 - ie: kernel only. 66 * 67 * func is the function to start. 68 * arg is the parameter to pass to function on first startup. 69 * newpp is the return value pointing to the thread's struct proc. 70 * flags are flags to fork1 (in unistd.h) 71 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 72 */ 73 int 74 kthread_create(void (*func)(void *), void *arg, 75 struct proc **newpp, int flags, const char *fmt, ...) 76 { 77 int error; 78 va_list ap; 79 struct proc *p2; 80 81 if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */) 82 panic("kthread_create called too soon"); 83 84 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 85 &p2); 86 if (error) 87 return error; 88 89 /* save a global descriptor, if desired */ 90 if (newpp != NULL) 91 *newpp = p2; 92 93 /* this is a non-swapped system process */ 94 PROC_LOCK(p2); 95 p2->p_flag |= P_SYSTEM | P_KTHREAD; 96 p2->p_procsig->ps_flag |= PS_NOCLDWAIT; 97 _PHOLD(p2); 98 PROC_UNLOCK(p2); 99 100 /* set up arg0 for 'ps', et al */ 101 va_start(ap, fmt); 102 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 103 va_end(ap); 104 105 /* call the processes' main()... */ 106 cpu_set_fork_handler(FIRST_THREAD_IN_PROC(p2), func, arg); 107 108 /* Delay putting it on the run queue until now. */ 109 mtx_lock_spin(&sched_lock); 110 p2->p_sflag |= PS_INMEM; 111 if (!(flags & RFSTOPPED)) { 112 setrunqueue(FIRST_THREAD_IN_PROC(p2)); 113 } 114 mtx_unlock_spin(&sched_lock); 115 116 return 0; 117 } 118 119 void 120 kthread_exit(int ecode) 121 { 122 struct thread *td; 123 struct proc *p; 124 125 td = curthread; 126 p = td->td_proc; 127 sx_xlock(&proctree_lock); 128 PROC_LOCK(p); 129 proc_reparent(p, initproc); 130 PROC_UNLOCK(p); 131 sx_xunlock(&proctree_lock); 132 exit1(td, W_EXITCODE(ecode, 0)); 133 } 134 135 /* 136 * Advise a kernel process to suspend (or resume) in its main loop. 137 * Participation is voluntary. 138 */ 139 int 140 kthread_suspend(struct proc *p, int timo) 141 { 142 /* 143 * Make sure this is indeed a system process and we can safely 144 * use the p_siglist field. 145 */ 146 PROC_LOCK(p); 147 if ((p->p_flag & P_KTHREAD) == 0) { 148 PROC_UNLOCK(p); 149 return (EINVAL); 150 } 151 SIGADDSET(p->p_siglist, SIGSTOP); 152 wakeup(p); 153 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo); 154 } 155 156 int 157 kthread_resume(struct proc *p) 158 { 159 /* 160 * Make sure this is indeed a system process and we can safely 161 * use the p_siglist field. 162 */ 163 PROC_LOCK(p); 164 if ((p->p_flag & P_KTHREAD) == 0) { 165 PROC_UNLOCK(p); 166 return (EINVAL); 167 } 168 SIGDELSET(p->p_siglist, SIGSTOP); 169 PROC_UNLOCK(p); 170 wakeup(&p->p_siglist); 171 return (0); 172 } 173 174 void 175 kthread_suspend_check(struct proc *p) 176 { 177 PROC_LOCK(p); 178 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 179 wakeup(&p->p_siglist); 180 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0); 181 } 182 PROC_UNLOCK(p); 183 } 184