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: src/sys/kern/kern_kthread.c,v 1.5.2.3 2001/12/25 01:51:14 dillon Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/proc.h> 32 #include <sys/kthread.h> 33 #include <sys/ptrace.h> 34 #include <sys/resourcevar.h> 35 #include <sys/signalvar.h> 36 #include <sys/unistd.h> 37 #include <sys/wait.h> 38 39 #include <machine/stdarg.h> 40 41 /* 42 * Start a kernel process. This is called after a fork() call in 43 * mi_startup() in the file kern/init_main.c. 44 * 45 * This function is used to start "internal" daemons and intended 46 * to be called from SYSINIT(). 47 */ 48 void 49 kproc_start(udata) 50 const void *udata; 51 { 52 const struct kproc_desc *kp = udata; 53 int error; 54 55 error = kthread_create((void (*)(void *))kp->func, NULL, 56 kp->global_procpp, kp->arg0); 57 if (error) 58 panic("kproc_start: %s: error %d", kp->arg0, error); 59 } 60 61 /* 62 * Create a kernel process/thread/whatever. It shares it's address space 63 * with proc0 - ie: kernel only. 64 */ 65 int 66 kthread_create(void (*func)(void *), void *arg, 67 struct proc **newpp, const char *fmt, ...) 68 { 69 int error; 70 va_list ap; 71 struct proc *p2; 72 73 if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */) { 74 panic("kthread_create called too soon"); 75 } 76 77 error = fork1(&proc0, RFMEM | RFFDG | RFPROC, &p2); 78 if (error) 79 return error; 80 81 /* save a global descriptor, if desired */ 82 if (newpp != NULL) 83 *newpp = p2; 84 85 /* this is a non-swapped system process */ 86 p2->p_flag |= P_INMEM | P_SYSTEM; 87 p2->p_procsig->ps_flag |= PS_NOCLDWAIT; 88 PHOLD(p2); 89 90 /* set up arg0 for 'ps', et al */ 91 va_start(ap, fmt); 92 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 93 va_end(ap); 94 95 /* call the processes' main()... */ 96 cpu_set_fork_handler(p2, func, arg); 97 98 return 0; 99 } 100 101 void 102 kthread_exit(int ecode) 103 { 104 proc_reparent(curproc, initproc); 105 exit1(curproc, W_EXITCODE(ecode, 0)); 106 } 107 108 /* 109 * Advise a kernel process to suspend (or resume) in its main loop. 110 * Participation is voluntary. 111 */ 112 int 113 suspend_kproc(struct proc *p, int timo) 114 { 115 /* 116 * Make sure this is indeed a system process and we can safely 117 * use the p_siglist field. 118 */ 119 if ((p->p_flag & P_SYSTEM) == 0) 120 return (EINVAL); 121 SIGADDSET(p->p_siglist, SIGSTOP); 122 wakeup(p); 123 return tsleep((caddr_t)&p->p_siglist, PPAUSE, "suspkp", timo); 124 } 125 126 int 127 resume_kproc(struct proc *p) 128 { 129 /* 130 * Make sure this is indeed a system process and we can safely 131 * use the p_siglist field. 132 */ 133 if ((p->p_flag & P_SYSTEM) == 0) 134 return (EINVAL); 135 SIGDELSET(p->p_siglist, SIGSTOP); 136 wakeup((caddr_t)&p->p_siglist); 137 return (0); 138 } 139 140 void 141 kproc_suspend_loop(struct proc *p) 142 { 143 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 144 wakeup((caddr_t)&p->p_siglist); 145 tsleep((caddr_t)&p->p_siglist, PPAUSE, "kpsusp", 0); 146 } 147 } 148