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, 0, 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 its address space 62 * with proc0 - ie: kernel only. 63 * 64 * func is the function to start. 65 * arg is the parameter to pass to function on first startup. 66 * newpp is the return value pointing to the thread's struct proc. 67 * flags are flags to fork1 (in unistd.h) 68 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 69 */ 70 int 71 kthread_create(void (*func)(void *), void *arg, 72 struct proc **newpp, int flags, const char *fmt, ...) 73 { 74 int error; 75 va_list ap; 76 struct proc *p2; 77 78 if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */) 79 panic("kthread_create called too soon"); 80 81 error = fork1(&proc0, RFMEM | RFFDG | RFPROC | flags, &p2); 82 if (error) 83 return error; 84 85 /* save a global descriptor, if desired */ 86 if (newpp != NULL) 87 *newpp = p2; 88 89 /* this is a non-swapped system process */ 90 p2->p_flag |= P_INMEM | P_SYSTEM; 91 p2->p_procsig->ps_flag |= PS_NOCLDWAIT; 92 PHOLD(p2); 93 94 /* set up arg0 for 'ps', et al */ 95 va_start(ap, fmt); 96 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 97 va_end(ap); 98 99 /* call the processes' main()... */ 100 cpu_set_fork_handler(p2, func, arg); 101 102 return 0; 103 } 104 105 void 106 kthread_exit(int ecode) 107 { 108 proc_reparent(curproc, initproc); 109 exit1(curproc, W_EXITCODE(ecode, 0)); 110 } 111 112 /* 113 * Advise a kernel process to suspend (or resume) in its main loop. 114 * Participation is voluntary. 115 */ 116 int 117 suspend_kproc(struct proc *p, int timo) 118 { 119 /* 120 * Make sure this is indeed a system process and we can safely 121 * use the p_siglist field. 122 */ 123 if ((p->p_flag & P_SYSTEM) == 0) 124 return (EINVAL); 125 SIGADDSET(p->p_siglist, SIGSTOP); 126 return tsleep((caddr_t)&p->p_siglist, PPAUSE, "suspkp", timo); 127 } 128 129 int 130 resume_kproc(struct proc *p) 131 { 132 /* 133 * Make sure this is indeed a system process and we can safely 134 * use the p_siglist field. 135 */ 136 if ((p->p_flag & P_SYSTEM) == 0) 137 return (EINVAL); 138 SIGDELSET(p->p_siglist, SIGSTOP); 139 wakeup((caddr_t)&p->p_siglist); 140 return (0); 141 } 142 143 void 144 kproc_suspend_loop(struct proc *p) 145 { 146 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 147 wakeup((caddr_t)&p->p_siglist); 148 tsleep((caddr_t)&p->p_siglist, PPAUSE, "kpsusp", 0); 149 } 150 } 151