1 f1e8706d 2004-12-27 devnull #include "u.h"
  2 f1e8706d 2004-12-27 devnull #include <errno.h>
  3 f1e8706d 2004-12-27 devnull #include <sys/types.h>
  4 f1e8706d 2004-12-27 devnull #include <sys/wait.h>
  5 f1e8706d 2004-12-27 devnull #include <sched.h>
  6 f1e8706d 2004-12-27 devnull #include <signal.h>
  7 f1e8706d 2004-12-27 devnull #include "libc.h"
  8 f1e8706d 2004-12-27 devnull #include "thread.h"
  9 f1e8706d 2004-12-27 devnull #include "threadimpl.h"
 10 f1e8706d 2004-12-27 devnull 
 11 f1e8706d 2004-12-27 devnull /*
 12 f1e8706d 2004-12-27 devnull  * spin locks
 13 f1e8706d 2004-12-27 devnull  */
 14 f1e8706d 2004-12-27 devnull extern int _tas(int*);
 15 f1e8706d 2004-12-27 devnull 
 16 f1e8706d 2004-12-27 devnull void
 17 f1e8706d 2004-12-27 devnull _threadunlock(Lock *l, ulong pc)
 18 f1e8706d 2004-12-27 devnull {
 19 f1e8706d 2004-12-27 devnull 	USED(pc);
 20 f1e8706d 2004-12-27 devnull 
 21 f1e8706d 2004-12-27 devnull 	l->held = 0;
 22 f1e8706d 2004-12-27 devnull }
 23 f1e8706d 2004-12-27 devnull 
 24 f1e8706d 2004-12-27 devnull int
 25 f1e8706d 2004-12-27 devnull _threadlock(Lock *l, int block, ulong pc)
 26 f1e8706d 2004-12-27 devnull {
 27 f1e8706d 2004-12-27 devnull 	int i;
 28 f1e8706d 2004-12-27 devnull 
 29 f1e8706d 2004-12-27 devnull 	USED(pc);
 30 f1e8706d 2004-12-27 devnull 
 31 f1e8706d 2004-12-27 devnull 	/* once fast */
 32 f1e8706d 2004-12-27 devnull 	if(!_tas(&l->held))
 33 f1e8706d 2004-12-27 devnull 		return 1;
 34 f1e8706d 2004-12-27 devnull 	if(!block)
 35 f1e8706d 2004-12-27 devnull 		return 0;
 36 f1e8706d 2004-12-27 devnull 
 37 f1e8706d 2004-12-27 devnull 	/* a thousand times pretty fast */
 38 f1e8706d 2004-12-27 devnull 	for(i=0; i<1000; i++){
 39 f1e8706d 2004-12-27 devnull 		if(!_tas(&l->held))
 40 f1e8706d 2004-12-27 devnull 			return 1;
 41 f1e8706d 2004-12-27 devnull 		sched_yield();
 42 f1e8706d 2004-12-27 devnull 	}
 43 f1e8706d 2004-12-27 devnull 	/* now nice and slow */
 44 f1e8706d 2004-12-27 devnull 	for(i=0; i<1000; i++){
 45 f1e8706d 2004-12-27 devnull 		if(!_tas(&l->held))
 46 f1e8706d 2004-12-27 devnull 			return 1;
 47 f1e8706d 2004-12-27 devnull 		usleep(100*1000);
 48 f1e8706d 2004-12-27 devnull 	}
 49 f1e8706d 2004-12-27 devnull 	/* take your time */
 50 f1e8706d 2004-12-27 devnull 	while(_tas(&l->held))
 51 f1e8706d 2004-12-27 devnull 		usleep(1000*1000);
 52 f1e8706d 2004-12-27 devnull 	return 1;
 53 f1e8706d 2004-12-27 devnull }
 54 f1e8706d 2004-12-27 devnull 
 55 f1e8706d 2004-12-27 devnull /*
 56 f1e8706d 2004-12-27 devnull  * sleep and wakeup
 57 f1e8706d 2004-12-27 devnull  */
 58 f1e8706d 2004-12-27 devnull static void
 59 f1e8706d 2004-12-27 devnull ign(int x)
 60 f1e8706d 2004-12-27 devnull {
 61 f1e8706d 2004-12-27 devnull 	USED(x);
 62 f1e8706d 2004-12-27 devnull }
 63 f1e8706d 2004-12-27 devnull 
 64 f1e8706d 2004-12-27 devnull static void /*__attribute__((constructor))*/
 65 f1e8706d 2004-12-27 devnull ignusr1(int restart)
 66 f1e8706d 2004-12-27 devnull {
 67 f1e8706d 2004-12-27 devnull 	struct sigaction sa;
 68 f1e8706d 2004-12-27 devnull 
 69 f1e8706d 2004-12-27 devnull 	memset(&sa, 0, sizeof sa);
 70 f1e8706d 2004-12-27 devnull 	sa.sa_handler = ign;
 71 f1e8706d 2004-12-27 devnull 	sigemptyset(&sa.sa_mask);
 72 f1e8706d 2004-12-27 devnull 	sigaddset(&sa.sa_mask, SIGUSR1);
 73 f1e8706d 2004-12-27 devnull 	if(restart)
 74 f1e8706d 2004-12-27 devnull 		sa.sa_flags = SA_RESTART;
 75 f1e8706d 2004-12-27 devnull 	sigaction(SIGUSR1, &sa, nil);
 76 f1e8706d 2004-12-27 devnull }
 77 f1e8706d 2004-12-27 devnull 
 78 f1e8706d 2004-12-27 devnull void
 79 f1e8706d 2004-12-27 devnull _procsleep(_Procrendez *r)
 80 f1e8706d 2004-12-27 devnull {
 81 f1e8706d 2004-12-27 devnull 	sigset_t mask;
 82 f1e8706d 2004-12-27 devnull 
 83 f1e8706d 2004-12-27 devnull 	/*
 84 f1e8706d 2004-12-27 devnull 	 * Go to sleep.
 85 f1e8706d 2004-12-27 devnull 	 *
 86 f1e8706d 2004-12-27 devnull 	 * Block USR1, set the handler to interrupt system calls,
 87 f1e8706d 2004-12-27 devnull 	 * unlock the vouslock so our waker can wake us,
 88 f1e8706d 2004-12-27 devnull 	 * and then suspend.
 89 f1e8706d 2004-12-27 devnull 	 */
 90 f1e8706d 2004-12-27 devnull 	r->asleep = 1;
 91 f1e8706d 2004-12-27 devnull 	r->pid = getpid();
 92 f1e8706d 2004-12-27 devnull 
 93 f1e8706d 2004-12-27 devnull 	sigprocmask(SIG_SETMASK, nil, &mask);
 94 f1e8706d 2004-12-27 devnull 	sigaddset(&mask, SIGUSR1);
 95 f1e8706d 2004-12-27 devnull 	sigprocmask(SIG_SETMASK, &mask, nil);
 96 f1e8706d 2004-12-27 devnull 	ignusr1(0);
 97 f1e8706d 2004-12-27 devnull 	unlock(r->l);
 98 f1e8706d 2004-12-27 devnull 	sigdelset(&mask, SIGUSR1);
 99 f1e8706d 2004-12-27 devnull 	sigsuspend(&mask);
100 f1e8706d 2004-12-27 devnull 
101 f1e8706d 2004-12-27 devnull 	/*
102 f1e8706d 2004-12-27 devnull 	 * We're awake.  Make USR1 not interrupt system calls.
103 f1e8706d 2004-12-27 devnull 	 */
104 f1e8706d 2004-12-27 devnull 	ignusr1(1);
105 f1e8706d 2004-12-27 devnull 	assert(r->asleep == 0);
106 f1e8706d 2004-12-27 devnull 	lock(r->l);
107 f1e8706d 2004-12-27 devnull }
108 f1e8706d 2004-12-27 devnull 
109 f1e8706d 2004-12-27 devnull void
110 f1e8706d 2004-12-27 devnull _procwakeup(_Procrendez *r)
111 f1e8706d 2004-12-27 devnull {
112 f1e8706d 2004-12-27 devnull 	if(r->asleep){
113 f1e8706d 2004-12-27 devnull 		r->asleep = 0;
114 f1e8706d 2004-12-27 devnull 		assert(r->pid >= 1);
115 f1e8706d 2004-12-27 devnull 		kill(r->pid, SIGUSR1);
116 f1e8706d 2004-12-27 devnull 	}
117 f1e8706d 2004-12-27 devnull }
118 f1e8706d 2004-12-27 devnull 
119 f1e8706d 2004-12-27 devnull /*
120 f1e8706d 2004-12-27 devnull  * process creation and exit
121 f1e8706d 2004-12-27 devnull  */
122 f1e8706d 2004-12-27 devnull typedef struct Stackfree Stackfree;
123 f1e8706d 2004-12-27 devnull struct Stackfree
124 f1e8706d 2004-12-27 devnull {
125 f1e8706d 2004-12-27 devnull 	Stackfree	*next;
126 f1e8706d 2004-12-27 devnull 	int	pid;
127 f1e8706d 2004-12-27 devnull };
128 f1e8706d 2004-12-27 devnull static Lock stacklock;
129 f1e8706d 2004-12-27 devnull static Stackfree *stackfree;
130 f1e8706d 2004-12-27 devnull 
131 f1e8706d 2004-12-27 devnull static void
132 f1e8706d 2004-12-27 devnull delayfreestack(uchar *stk)
133 f1e8706d 2004-12-27 devnull {
134 f1e8706d 2004-12-27 devnull 	Stackfree *sf;
135 f1e8706d 2004-12-27 devnull 
136 f1e8706d 2004-12-27 devnull 	sf = (Stackfree*)stk;
137 f1e8706d 2004-12-27 devnull 	sf->pid = getpid();
138 f1e8706d 2004-12-27 devnull 	lock(&stacklock);
139 f1e8706d 2004-12-27 devnull 	sf->next = stackfree;
140 f1e8706d 2004-12-27 devnull 	stackfree = sf;
141 f1e8706d 2004-12-27 devnull 	unlock(&stacklock);
142 f1e8706d 2004-12-27 devnull }
143 f1e8706d 2004-12-27 devnull 
144 f1e8706d 2004-12-27 devnull static void
145 f1e8706d 2004-12-27 devnull dofreestacks(void)
146 f1e8706d 2004-12-27 devnull {
147 f1e8706d 2004-12-27 devnull 	Stackfree *sf, *last, *next;
148 f1e8706d 2004-12-27 devnull 
149 f1e8706d 2004-12-27 devnull 	if(stackfree==nil || !canlock(&stacklock))
150 f1e8706d 2004-12-27 devnull 		return;
151 f1e8706d 2004-12-27 devnull 
152 f1e8706d 2004-12-27 devnull 	for(last=nil,sf=stackfree; sf; last=sf,sf=next){
153 f1e8706d 2004-12-27 devnull 		next = sf->next;
154 f1e8706d 2004-12-27 devnull 		if(sf->pid >= 1 && kill(sf->pid, 0) < 0 && errno == ESRCH){
155 f1e8706d 2004-12-27 devnull 			free(sf);
156 f1e8706d 2004-12-27 devnull 			last->next = next;
157 f1e8706d 2004-12-27 devnull 			sf = last;
158 f1e8706d 2004-12-27 devnull 		}
159 f1e8706d 2004-12-27 devnull 	}
160 f1e8706d 2004-12-27 devnull }	
161 f1e8706d 2004-12-27 devnull 
162 f1e8706d 2004-12-27 devnull static int
163 f1e8706d 2004-12-27 devnull startprocfn(void *v)
164 f1e8706d 2004-12-27 devnull {
165 f1e8706d 2004-12-27 devnull 	void **a;
166 f1e8706d 2004-12-27 devnull 	uchar *stk;
167 f1e8706d 2004-12-27 devnull 	void (*fn)(void*);
168 f1e8706d 2004-12-27 devnull 	Proc *p;
169 f1e8706d 2004-12-27 devnull 
170 f1e8706d 2004-12-27 devnull 	a = (void**)v;
171 f1e8706d 2004-12-27 devnull 	fn = a[0];
172 f1e8706d 2004-12-27 devnull 	p = a[1];
173 f1e8706d 2004-12-27 devnull 	stk = a[2];
174 f1e8706d 2004-12-27 devnull 	free(a);
175 f1e8706d 2004-12-27 devnull 	p->osprocid = getpid();
176 f1e8706d 2004-12-27 devnull 
177 f1e8706d 2004-12-27 devnull 	(*fn)(p);
178 f1e8706d 2004-12-27 devnull 
179 f1e8706d 2004-12-27 devnull 	delayfreestack(stk);
180 f1e8706d 2004-12-27 devnull 	_exit(0);
181 f1e8706d 2004-12-27 devnull 	return 0;
182 f1e8706d 2004-12-27 devnull }
183 f1e8706d 2004-12-27 devnull 
184 f1e8706d 2004-12-27 devnull /*
185 f1e8706d 2004-12-27 devnull  * indirect through here so that parent need not wait for child zombie
186 f1e8706d 2004-12-27 devnull  * 
187 f1e8706d 2004-12-27 devnull  * slight race - if child exits and then another process starts before we 
188 f1e8706d 2004-12-27 devnull  * manage to exit, we'll be running on a freed stack.
189 f1e8706d 2004-12-27 devnull  */
190 f1e8706d 2004-12-27 devnull static int
191 f1e8706d 2004-12-27 devnull trampnowait(void *v)
192 f1e8706d 2004-12-27 devnull {
193 f1e8706d 2004-12-27 devnull 	void **a;
194 f1e8706d 2004-12-27 devnull 
195 f1e8706d 2004-12-27 devnull 	a = (void*)v;
196 f1e8706d 2004-12-27 devnull 	*(int*)a[3] = clone(startprocfn, a[2]+65536-512, CLONE_VM|CLONE_FILES, a);
197 f1e8706d 2004-12-27 devnull 	_exit(0);
198 f1e8706d 2004-12-27 devnull 	return 0;
199 f1e8706d 2004-12-27 devnull }
200 f1e8706d 2004-12-27 devnull 
201 f1e8706d 2004-12-27 devnull void
202 f1e8706d 2004-12-27 devnull _procstart(Proc *p, void (*fn)(Proc*))
203 f1e8706d 2004-12-27 devnull {
204 f1e8706d 2004-12-27 devnull 	void **a;
205 f1e8706d 2004-12-27 devnull 	uchar *stk;
206 f1e8706d 2004-12-27 devnull 	int pid, kidpid, status;
207 f1e8706d 2004-12-27 devnull 
208 f1e8706d 2004-12-27 devnull 	dofreestacks();
209 f1e8706d 2004-12-27 devnull 	a = malloc(4*sizeof a[0]);
210 f1e8706d 2004-12-27 devnull 	if(a == nil)
211 f1e8706d 2004-12-27 devnull 		sysfatal("_procstart malloc: %r");
212 f1e8706d 2004-12-27 devnull 	stk = malloc(65536);
213 f1e8706d 2004-12-27 devnull 	if(stk == nil)
214 f1e8706d 2004-12-27 devnull 		sysfatal("_procstart malloc stack: %r");
215 f1e8706d 2004-12-27 devnull 
216 f1e8706d 2004-12-27 devnull 	a[0] = fn;
217 f1e8706d 2004-12-27 devnull 	a[1] = p;
218 f1e8706d 2004-12-27 devnull 	a[2] = stk;
219 f1e8706d 2004-12-27 devnull 	a[3] = &kidpid;
220 f1e8706d 2004-12-27 devnull 	kidpid = -1;
221 f1e8706d 2004-12-27 devnull 
222 f1e8706d 2004-12-27 devnull 	pid = clone(trampnowait, stk+65536-16, CLONE_VM|CLONE_FILES, a);
223 f1e8706d 2004-12-27 devnull 	if(pid > 0)
224 f1e8706d 2004-12-27 devnull 		if(wait4(pid, &status, __WALL, 0) < 0)
225 f1e8706d 2004-12-27 devnull 			fprint(2, "ffork wait4: %r\n");
226 f1e8706d 2004-12-27 devnull 	if(pid < 0 || kidpid < 0){
227 f1e8706d 2004-12-27 devnull 		fprint(2, "_procstart clone: %r\n");
228 f1e8706d 2004-12-27 devnull 		abort();
229 f1e8706d 2004-12-27 devnull 	}
230 f1e8706d 2004-12-27 devnull }
231 f1e8706d 2004-12-27 devnull 
232 f1e8706d 2004-12-27 devnull static char *threadexitsmsg;
233 f1e8706d 2004-12-27 devnull void
234 f1e8706d 2004-12-27 devnull sigusr2handler(int s)
235 f1e8706d 2004-12-27 devnull {
236 f1e8706d 2004-12-27 devnull 	if(threadexitsmsg)
237 f1e8706d 2004-12-27 devnull 		_exits(threadexitsmsg);
238 f1e8706d 2004-12-27 devnull }
239 f1e8706d 2004-12-27 devnull 
240 f1e8706d 2004-12-27 devnull void
241 f1e8706d 2004-12-27 devnull threadexitsall(char *msg)
242 f1e8706d 2004-12-27 devnull {
243 f1e8706d 2004-12-27 devnull 	static int pid[1024];
244 f1e8706d 2004-12-27 devnull 	int i, npid, mypid;
245 f1e8706d 2004-12-27 devnull 	Proc *p;
246 f1e8706d 2004-12-27 devnull 
247 f1e8706d 2004-12-27 devnull 	if(msg == nil)
248 f1e8706d 2004-12-27 devnull 		msg = "";
249 f1e8706d 2004-12-27 devnull 	mypid = getpid();
250 f1e8706d 2004-12-27 devnull 	lock(&_threadprocslock);
251 f1e8706d 2004-12-27 devnull 	threadexitsmsg = msg;
252 f1e8706d 2004-12-27 devnull 	npid = 0;
253 f1e8706d 2004-12-27 devnull 	for(p=_threadprocs; p; p=p->next)
254 f1e8706d 2004-12-27 devnull 		if(p->osprocid != mypid && p->osprocid >= 1)
255 f1e8706d 2004-12-27 devnull 			pid[npid++] = p->osprocid;
256 f1e8706d 2004-12-27 devnull 	for(i=0; i<npid; i++)
257 f1e8706d 2004-12-27 devnull 		kill(pid[i], SIGUSR2);
258 f1e8706d 2004-12-27 devnull 	unlock(&_threadprocslock);
259 f1e8706d 2004-12-27 devnull 	exits(msg);
260 f1e8706d 2004-12-27 devnull }
261 f1e8706d 2004-12-27 devnull 
262 f1e8706d 2004-12-27 devnull /*
263 f1e8706d 2004-12-27 devnull  * per-process data, indexed by pid
264 f1e8706d 2004-12-27 devnull  *
265 f1e8706d 2004-12-27 devnull  * could use modify_ldt and a segment register
266 f1e8706d 2004-12-27 devnull  * to avoid the many calls to getpid(), but i don't
267 f1e8706d 2004-12-27 devnull  * care -- this is compatibility code.  linux 2.6 with
268 f1e8706d 2004-12-27 devnull  * nptl is a good enough pthreads to avoid this whole file.
269 f1e8706d 2004-12-27 devnull  */
270 f1e8706d 2004-12-27 devnull typedef struct Perproc Perproc;
271 f1e8706d 2004-12-27 devnull struct Perproc
272 f1e8706d 2004-12-27 devnull {
273 f1e8706d 2004-12-27 devnull 	int		pid;
274 f1e8706d 2004-12-27 devnull 	Proc	*proc;
275 f1e8706d 2004-12-27 devnull };
276 f1e8706d 2004-12-27 devnull 
277 f1e8706d 2004-12-27 devnull static Lock perlock;
278 f1e8706d 2004-12-27 devnull static Perproc perproc[1024];
279 f1e8706d 2004-12-27 devnull #define P ((Proc*)-1)
280 f1e8706d 2004-12-27 devnull 
281 f1e8706d 2004-12-27 devnull static Perproc*
282 f1e8706d 2004-12-27 devnull myperproc(void)
283 f1e8706d 2004-12-27 devnull {
284 f1e8706d 2004-12-27 devnull 	int i, pid, h;
285 f1e8706d 2004-12-27 devnull 	Perproc *p;
286 f1e8706d 2004-12-27 devnull 
287 f1e8706d 2004-12-27 devnull 	pid = getpid();
288 f1e8706d 2004-12-27 devnull 	h = pid%nelem(perproc);
289 f1e8706d 2004-12-27 devnull 	for(i=0; i<nelem(perproc); i++){
290 f1e8706d 2004-12-27 devnull 		p = &perproc[(i+h)%nelem(perproc)];
291 f1e8706d 2004-12-27 devnull 		if(p->pid == pid)
292 f1e8706d 2004-12-27 devnull 			return p;
293 f1e8706d 2004-12-27 devnull 		if(p->pid == 0){
294 f1e8706d 2004-12-27 devnull 			print("found 0 at %d (h=%d)\n", (i+h)%nelem(perproc), h);
295 f1e8706d 2004-12-27 devnull 			break;
296 f1e8706d 2004-12-27 devnull 		}
297 f1e8706d 2004-12-27 devnull 	}
298 f1e8706d 2004-12-27 devnull 	fprint(2, "myperproc %d: cannot find self\n", pid);
299 f1e8706d 2004-12-27 devnull 	abort();
300 f1e8706d 2004-12-27 devnull 	return nil;
301 f1e8706d 2004-12-27 devnull }
302 f1e8706d 2004-12-27 devnull 
303 f1e8706d 2004-12-27 devnull static Perproc*
304 f1e8706d 2004-12-27 devnull newperproc(void)
305 f1e8706d 2004-12-27 devnull {
306 f1e8706d 2004-12-27 devnull 	int i, pid, h;
307 f1e8706d 2004-12-27 devnull 	Perproc *p;
308 f1e8706d 2004-12-27 devnull 
309 f1e8706d 2004-12-27 devnull 	lock(&perlock);
310 f1e8706d 2004-12-27 devnull 	pid = getpid();
311 f1e8706d 2004-12-27 devnull 	h = pid%nelem(perproc);
312 f1e8706d 2004-12-27 devnull 	for(i=0; i<nelem(perproc); i++){
313 f1e8706d 2004-12-27 devnull 		p = &perproc[(i+h)%nelem(perproc)];
314 f1e8706d 2004-12-27 devnull 		if(p->pid == pid || p->pid == -1 || p->pid == 0){
315 f1e8706d 2004-12-27 devnull 			p->pid = pid;
316 f1e8706d 2004-12-27 devnull 			unlock(&perlock);
317 f1e8706d 2004-12-27 devnull 			return p;
318 f1e8706d 2004-12-27 devnull 		}
319 f1e8706d 2004-12-27 devnull 	}
320 f1e8706d 2004-12-27 devnull 	fprint(2, "newperproc %d: out of procs\n", pid);
321 f1e8706d 2004-12-27 devnull 	abort();
322 f1e8706d 2004-12-27 devnull 	return nil;
323 f1e8706d 2004-12-27 devnull }
324 f1e8706d 2004-12-27 devnull 
325 f1e8706d 2004-12-27 devnull Proc*
326 f1e8706d 2004-12-27 devnull _threadproc(void)
327 f1e8706d 2004-12-27 devnull {
328 f1e8706d 2004-12-27 devnull 	return myperproc()->proc;
329 f1e8706d 2004-12-27 devnull }
330 f1e8706d 2004-12-27 devnull 
331 f1e8706d 2004-12-27 devnull void
332 f1e8706d 2004-12-27 devnull _threadsetproc(Proc *p)
333 f1e8706d 2004-12-27 devnull {
334 f1e8706d 2004-12-27 devnull 	Perproc *pp;
335 f1e8706d 2004-12-27 devnull 
336 f1e8706d 2004-12-27 devnull 	p->osprocid = getpid();
337 f1e8706d 2004-12-27 devnull 	pp = newperproc();
338 f1e8706d 2004-12-27 devnull 	pp->proc = p;
339 f1e8706d 2004-12-27 devnull 	if(p == nil)
340 f1e8706d 2004-12-27 devnull 		pp->pid = -1;
341 f1e8706d 2004-12-27 devnull }
342 f1e8706d 2004-12-27 devnull 
343 f1e8706d 2004-12-27 devnull void
344 f1e8706d 2004-12-27 devnull _pthreadinit(void)
345 f1e8706d 2004-12-27 devnull {
346 f1e8706d 2004-12-27 devnull 	signal(SIGUSR2, sigusr2handler);
347 f1e8706d 2004-12-27 devnull }
348 f1e8706d 2004-12-27 devnull