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