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 error = fork1(&proc0, RFMEM | RFFDG | RFPROC, &p2); 73 if (error) 74 return error; 75 76 /* save a global descriptor, if desired */ 77 if (newpp != NULL) 78 *newpp = p2; 79 80 /* this is a non-swapped system process */ 81 p2->p_flag |= P_INMEM | P_SYSTEM; 82 p2->p_procsig->ps_flag |= PS_NOCLDWAIT; 83 PHOLD(p2); 84 85 /* set up arg0 for 'ps', et al */ 86 va_start(ap, fmt); 87 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 88 va_end(ap); 89 90 /* call the processes' main()... */ 91 cpu_set_fork_handler(p2, func, arg); 92 93 return 0; 94 } 95 96 void 97 kthread_exit(int ecode) 98 { 99 exit1(curproc, W_EXITCODE(ecode, 0)); 100 } 101 102 /* 103 * Advise a kernel process to suspend (or resume) in its main loop. 104 * Participation is voluntary. 105 */ 106 int 107 suspend_kproc(struct proc *p, int timo) 108 { 109 /* 110 * Make sure this is indeed a system process and we can safely 111 * use the p_siglist field. 112 */ 113 if ((p->p_flag & P_SYSTEM) == 0) 114 return (EINVAL); 115 SIGADDSET(p->p_siglist, SIGSTOP); 116 return tsleep((caddr_t)&p->p_siglist, PPAUSE, "suspkp", timo); 117 } 118 119 int 120 resume_kproc(struct proc *p) 121 { 122 /* 123 * Make sure this is indeed a system process and we can safely 124 * use the p_siglist field. 125 */ 126 if ((p->p_flag & P_SYSTEM) == 0) 127 return (EINVAL); 128 SIGDELSET(p->p_siglist, SIGSTOP); 129 wakeup((caddr_t)&p->p_siglist); 130 return (0); 131 } 132 133 void 134 kproc_suspend_loop(struct proc *p) 135 { 136 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 137 wakeup((caddr_t)&p->p_siglist); 138 tsleep((caddr_t)&p->p_siglist, PPAUSE, "kpsusp", 0); 139 } 140 } 141