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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kthread.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/proc.h> 36 #include <sys/resourcevar.h> 37 #include <sys/signalvar.h> 38 #include <sys/sx.h> 39 #include <sys/unistd.h> 40 #include <sys/wait.h> 41 42 #include <machine/stdarg.h> 43 44 /* 45 * Start a kernel process. This is called after a fork() call in 46 * mi_startup() in the file kern/init_main.c. 47 * 48 * This function is used to start "internal" daemons and intended 49 * to be called from SYSINIT(). 50 */ 51 void 52 kproc_start(udata) 53 const void *udata; 54 { 55 const struct kproc_desc *kp = udata; 56 int error; 57 58 error = kthread_create((void (*)(void *))kp->func, NULL, 59 kp->global_procpp, 0, 0, "%s", kp->arg0); 60 if (error) 61 panic("kproc_start: %s: error %d", kp->arg0, error); 62 } 63 64 /* 65 * Create a kernel process/thread/whatever. It shares its address space 66 * with proc0 - ie: kernel only. 67 * 68 * func is the function to start. 69 * arg is the parameter to pass to function on first startup. 70 * newpp is the return value pointing to the thread's struct proc. 71 * flags are flags to fork1 (in unistd.h) 72 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 73 */ 74 int 75 kthread_create(void (*func)(void *), void *arg, 76 struct proc **newpp, int flags, int pages, const char *fmt, ...) 77 { 78 int error; 79 va_list ap; 80 struct thread *td; 81 struct proc *p2; 82 83 if (!proc0.p_stats) 84 panic("kthread_create called too soon"); 85 86 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 87 pages, &p2); 88 if (error) 89 return error; 90 91 /* save a global descriptor, if desired */ 92 if (newpp != NULL) 93 *newpp = p2; 94 95 /* this is a non-swapped system process */ 96 PROC_LOCK(p2); 97 p2->p_flag |= P_SYSTEM | P_KTHREAD; 98 mtx_lock(&p2->p_sigacts->ps_mtx); 99 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT; 100 mtx_unlock(&p2->p_sigacts->ps_mtx); 101 PROC_UNLOCK(p2); 102 103 /* set up arg0 for 'ps', et al */ 104 va_start(ap, fmt); 105 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 106 va_end(ap); 107 108 /* call the processes' main()... */ 109 td = FIRST_THREAD_IN_PROC(p2); 110 cpu_set_fork_handler(td, func, arg); 111 TD_SET_CAN_RUN(td); 112 113 /* Delay putting it on the run queue until now. */ 114 if (!(flags & RFSTOPPED)) { 115 mtx_lock_spin(&sched_lock); 116 setrunqueue(td, SRQ_BORING); 117 mtx_unlock_spin(&sched_lock); 118 } 119 120 return 0; 121 } 122 123 void 124 kthread_exit(int ecode) 125 { 126 struct thread *td; 127 struct proc *p; 128 129 td = curthread; 130 p = td->td_proc; 131 132 /* 133 * Reparent curthread from proc0 to init so that the zombie 134 * is harvested. 135 */ 136 sx_xlock(&proctree_lock); 137 PROC_LOCK(p); 138 proc_reparent(p, initproc); 139 PROC_UNLOCK(p); 140 sx_xunlock(&proctree_lock); 141 142 /* 143 * Wakeup anyone waiting for us to exit. 144 */ 145 wakeup(p); 146 147 /* Buh-bye! */ 148 exit1(td, W_EXITCODE(ecode, 0)); 149 } 150 151 /* 152 * Advise a kernel process to suspend (or resume) in its main loop. 153 * Participation is voluntary. 154 */ 155 int 156 kthread_suspend(struct proc *p, int timo) 157 { 158 /* 159 * Make sure this is indeed a system process and we can safely 160 * use the p_siglist field. 161 */ 162 PROC_LOCK(p); 163 if ((p->p_flag & P_KTHREAD) == 0) { 164 PROC_UNLOCK(p); 165 return (EINVAL); 166 } 167 SIGADDSET(p->p_siglist, SIGSTOP); 168 wakeup(p); 169 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo); 170 } 171 172 int 173 kthread_resume(struct proc *p) 174 { 175 /* 176 * Make sure this is indeed a system process and we can safely 177 * use the p_siglist field. 178 */ 179 PROC_LOCK(p); 180 if ((p->p_flag & P_KTHREAD) == 0) { 181 PROC_UNLOCK(p); 182 return (EINVAL); 183 } 184 SIGDELSET(p->p_siglist, SIGSTOP); 185 PROC_UNLOCK(p); 186 wakeup(&p->p_siglist); 187 return (0); 188 } 189 190 void 191 kthread_suspend_check(struct proc *p) 192 { 193 PROC_LOCK(p); 194 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 195 wakeup(&p->p_siglist); 196 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0); 197 } 198 PROC_UNLOCK(p); 199 } 200