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, 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, int pages, const char *fmt, ...) 76 { 77 int error; 78 va_list ap; 79 struct thread *td; 80 struct proc *p2; 81 82 if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */) 83 panic("kthread_create called too soon"); 84 85 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 86 pages, &p2); 87 if (error) 88 return error; 89 90 /* save a global descriptor, if desired */ 91 if (newpp != NULL) 92 *newpp = p2; 93 94 /* this is a non-swapped system process */ 95 PROC_LOCK(p2); 96 p2->p_flag |= P_SYSTEM | P_KTHREAD; 97 p2->p_procsig->ps_flag |= PS_NOCLDWAIT; 98 _PHOLD(p2); 99 PROC_UNLOCK(p2); 100 101 /* set up arg0 for 'ps', et al */ 102 va_start(ap, fmt); 103 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 104 va_end(ap); 105 106 /* call the processes' main()... */ 107 td = FIRST_THREAD_IN_PROC(p2); 108 cpu_set_fork_handler(td, func, arg); 109 TD_SET_CAN_RUN(td); 110 111 /* Delay putting it on the run queue until now. */ 112 mtx_lock_spin(&sched_lock); 113 p2->p_sflag |= PS_INMEM; 114 if (!(flags & RFSTOPPED)) { 115 setrunqueue(td); 116 } 117 mtx_unlock_spin(&sched_lock); 118 119 return 0; 120 } 121 122 void 123 kthread_exit(int ecode) 124 { 125 struct thread *td; 126 struct proc *p; 127 128 td = curthread; 129 p = td->td_proc; 130 sx_xlock(&proctree_lock); 131 PROC_LOCK(p); 132 proc_reparent(p, initproc); 133 PROC_UNLOCK(p); 134 sx_xunlock(&proctree_lock); 135 exit1(td, W_EXITCODE(ecode, 0)); 136 } 137 138 /* 139 * Advise a kernel process to suspend (or resume) in its main loop. 140 * Participation is voluntary. 141 */ 142 int 143 kthread_suspend(struct proc *p, int timo) 144 { 145 /* 146 * Make sure this is indeed a system process and we can safely 147 * use the p_siglist field. 148 */ 149 PROC_LOCK(p); 150 if ((p->p_flag & P_KTHREAD) == 0) { 151 PROC_UNLOCK(p); 152 return (EINVAL); 153 } 154 SIGADDSET(p->p_siglist, SIGSTOP); 155 wakeup(p); 156 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo); 157 } 158 159 int 160 kthread_resume(struct proc *p) 161 { 162 /* 163 * Make sure this is indeed a system process and we can safely 164 * use the p_siglist field. 165 */ 166 PROC_LOCK(p); 167 if ((p->p_flag & P_KTHREAD) == 0) { 168 PROC_UNLOCK(p); 169 return (EINVAL); 170 } 171 SIGDELSET(p->p_siglist, SIGSTOP); 172 PROC_UNLOCK(p); 173 wakeup(&p->p_siglist); 174 return (0); 175 } 176 177 void 178 kthread_suspend_check(struct proc *p) 179 { 180 PROC_LOCK(p); 181 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 182 wakeup(&p->p_siglist); 183 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0); 184 } 185 PROC_UNLOCK(p); 186 } 187