1 cea10000 2005-05-01 devnull #include "threadimpl.h"
  2 cea10000 2005-05-01 devnull #include "BSD.c"
  3 cea10000 2005-05-01 devnull 
  4 b20b42b8 2005-08-10 devnull #include <dlfcn.h>
  5 fe8c925e 2005-07-21 devnull 
  6 b20b42b8 2005-08-10 devnull #define MIN(a,b)	((a) < (b) ? (a) : (b))
  7 b20b42b8 2005-08-10 devnull #define MAX(a,b)	((a) > (b) ? (a) : (b))
  8 b20b42b8 2005-08-10 devnull 
  9 b20b42b8 2005-08-10 devnull enum {
 10 b20b42b8 2005-08-10 devnull 	FD_READ = 1,
 11 b20b42b8 2005-08-10 devnull 	FD_WRITE,
 12 b20b42b8 2005-08-10 devnull 	FD_RDWR,
 13 b20b42b8 2005-08-10 devnull 	FDTBL_MAXSIZE = 128
 14 b20b42b8 2005-08-10 devnull };
 15 b20b42b8 2005-08-10 devnull 
 16 b20b42b8 2005-08-10 devnull struct fd_entry {
 17 b20b42b8 2005-08-10 devnull 	QLock	lock;
 18 b20b42b8 2005-08-10 devnull 	int	fd;
 19 b20b42b8 2005-08-10 devnull 	int	id;
 20 b20b42b8 2005-08-10 devnull 	short	rc;
 21 b20b42b8 2005-08-10 devnull 	short	wc;
 22 b20b42b8 2005-08-10 devnull 	short	ref;
 23 b20b42b8 2005-08-10 devnull };
 24 b20b42b8 2005-08-10 devnull 
 25 b20b42b8 2005-08-10 devnull static struct fd_entry fd_entry1 = { .fd -1 };
 26 b20b42b8 2005-08-10 devnull static struct fd_entry *fd_table = nil;
 27 b20b42b8 2005-08-10 devnull static spinlock_t fd_table_lock = { 0, 0, nil, 0 };
 28 b20b42b8 2005-08-10 devnull static spinlock_t mlock = { 0, 0, nil, 0 };
 29 b20b42b8 2005-08-10 devnull static spinlock_t dl_lock = { 0, 0, nil, 0 };
 30 b20b42b8 2005-08-10 devnull 
 31 fe8c925e 2005-07-21 devnull void
 32 fe8c925e 2005-07-21 devnull _thread_malloc_lock(void)
 33 fe8c925e 2005-07-21 devnull {
 34 fe8c925e 2005-07-21 devnull 	_spinlock(&mlock);
 35 fe8c925e 2005-07-21 devnull }
 36 fe8c925e 2005-07-21 devnull 
 37 fe8c925e 2005-07-21 devnull void
 38 fe8c925e 2005-07-21 devnull _thread_malloc_unlock(void)
 39 fe8c925e 2005-07-21 devnull {
 40 fe8c925e 2005-07-21 devnull 	_spinunlock(&mlock);
 41 fe8c925e 2005-07-21 devnull }
 42 fe8c925e 2005-07-21 devnull 
 43 fe8c925e 2005-07-21 devnull void
 44 fe8c925e 2005-07-21 devnull _thread_malloc_init(void)
 45 fe8c925e 2005-07-21 devnull {
 46 fe8c925e 2005-07-21 devnull }
 47 b20b42b8 2005-08-10 devnull 
 48 b20b42b8 2005-08-10 devnull /*
 49 b20b42b8 2005-08-10 devnull  * Must set errno on failure because the return value
 50 b20b42b8 2005-08-10 devnull  * of _thread_fd_entry is propagated back to the caller
 51 b20b42b8 2005-08-10 devnull  * of the thread-wrapped libc function.
 52 b20b42b8 2005-08-10 devnull  */
 53 b20b42b8 2005-08-10 devnull static struct fd_entry *
 54 b20b42b8 2005-08-10 devnull _thread_fd_lookup(int fd)
 55 b20b42b8 2005-08-10 devnull {
 56 b20b42b8 2005-08-10 devnull 	struct fd_entry *t;
 57 b20b42b8 2005-08-10 devnull 	static int cursize;
 58 b20b42b8 2005-08-10 devnull 	int newsize;
 59 b20b42b8 2005-08-10 devnull 
 60 b20b42b8 2005-08-10 devnull 	if(fd >= FDTBL_MAXSIZE) {
 61 b20b42b8 2005-08-10 devnull 		errno = EBADF;
 62 b20b42b8 2005-08-10 devnull 		return nil;
 63 b20b42b8 2005-08-10 devnull 	}
 64 b20b42b8 2005-08-10 devnull 
 65 b20b42b8 2005-08-10 devnull 	/*
 66 b20b42b8 2005-08-10 devnull 	 * There are currently only a few libc functions using 
 67 b20b42b8 2005-08-10 devnull 	 * _thread_fd_*, which are rarely called by P9P programs.
 68 b20b42b8 2005-08-10 devnull 	 * So the contention for these locks is very small and so
 69 b20b42b8 2005-08-10 devnull 	 * far have usually been limited to a single fd. So
 70 b20b42b8 2005-08-10 devnull 	 * rather than malloc the fd_table everytime we just use
 71 b20b42b8 2005-08-10 devnull 	 * a single fd_entry until a lock request for another fd
 72 b20b42b8 2005-08-10 devnull 	 * comes in.
 73 b20b42b8 2005-08-10 devnull 	 */
 74 b20b42b8 2005-08-10 devnull 	if(fd_table == nil)
 75 b20b42b8 2005-08-10 devnull 		if(fd_entry1.fd == -1) {
 76 b20b42b8 2005-08-10 devnull 			fd_entry1.fd = fd;
 77 b20b42b8 2005-08-10 devnull 			return &fd_entry1;
 78 b20b42b8 2005-08-10 devnull 		} else if(fd_entry1.fd == fd)
 79 b20b42b8 2005-08-10 devnull 			return &fd_entry1;
 80 b20b42b8 2005-08-10 devnull 		else {
 81 b20b42b8 2005-08-10 devnull 			cursize = MAX(fd_entry1.fd, 16);
 82 b20b42b8 2005-08-10 devnull 			fd_table = malloc(cursize*sizeof(fd_table[0]));
 83 b20b42b8 2005-08-10 devnull 			if(fd_table == nil) {
 84 b20b42b8 2005-08-10 devnull 				errno = ENOMEM;
 85 b20b42b8 2005-08-10 devnull 				return nil;
 86 b20b42b8 2005-08-10 devnull 			}
 87 b20b42b8 2005-08-10 devnull 			memset(fd_table, 0, cursize*sizeof(fd_table[0]));
 88 b20b42b8 2005-08-10 devnull 			fd_table[fd_entry1.fd] = fd_entry1;
 89 b20b42b8 2005-08-10 devnull 		}
 90 b20b42b8 2005-08-10 devnull 	if(fd > cursize) {
 91 b20b42b8 2005-08-10 devnull 		newsize = MIN(cursize*2, FDTBL_MAXSIZE);
 92 b20b42b8 2005-08-10 devnull 		t = realloc(fd_table, newsize*sizeof(fd_table[0]));
 93 b20b42b8 2005-08-10 devnull 		if(t == nil) {
 94 b20b42b8 2005-08-10 devnull 			errno = ENOMEM;
 95 b20b42b8 2005-08-10 devnull 			return nil;
 96 b20b42b8 2005-08-10 devnull 		}
 97 b20b42b8 2005-08-10 devnull 		fd_table = t;
 98 b20b42b8 2005-08-10 devnull 		cursize = newsize; 
 99 b20b42b8 2005-08-10 devnull 		memset(fd_table, 0, cursize*sizeof(fd_table[0]));
100 b20b42b8 2005-08-10 devnull 	}
101 b20b42b8 2005-08-10 devnull 
102 b20b42b8 2005-08-10 devnull 	return &fd_table[fd];
103 b20b42b8 2005-08-10 devnull }
104 b20b42b8 2005-08-10 devnull 
105 b20b42b8 2005-08-10 devnull /*
106 b20b42b8 2005-08-10 devnull  * Mutiple readers just share the lock by incrementing the read count.
107 b20b42b8 2005-08-10 devnull  * Writers must obtain an exclusive lock.
108 b20b42b8 2005-08-10 devnull  */
109 b20b42b8 2005-08-10 devnull int
110 b20b42b8 2005-08-10 devnull _thread_fd_lock(int fd, int type, struct timespec *time)
111 b20b42b8 2005-08-10 devnull {
112 b20b42b8 2005-08-10 devnull 	struct fd_entry *fde;
113 b20b42b8 2005-08-10 devnull 	int id;
114 b20b42b8 2005-08-10 devnull 
115 b20b42b8 2005-08-10 devnull 	_spinlock(&fd_table_lock);
116 b20b42b8 2005-08-10 devnull 	fde = _thread_fd_lookup(fd);
117 b20b42b8 2005-08-10 devnull 	if(fde == nil)
118 b20b42b8 2005-08-10 devnull 		return -1;
119 b20b42b8 2005-08-10 devnull 
120 b20b42b8 2005-08-10 devnull 	if(type == FD_READ) {
121 b20b42b8 2005-08-10 devnull 		if(fde->rc++ >= 1 && fde->wc == 0) {
122 b20b42b8 2005-08-10 devnull 			_spinunlock(&fd_table_lock);
123 b20b42b8 2005-08-10 devnull 			return 0;
124 b20b42b8 2005-08-10 devnull 		}
125 b20b42b8 2005-08-10 devnull 	} else
126 b20b42b8 2005-08-10 devnull 		fde->wc++;
127 b20b42b8 2005-08-10 devnull 	_spinunlock(&fd_table_lock);
128 b20b42b8 2005-08-10 devnull 
129 b20b42b8 2005-08-10 devnull 	/* handle recursion */
130 b20b42b8 2005-08-10 devnull 	id = proc()->osprocid;
131 b20b42b8 2005-08-10 devnull 	if(id == fde->id) {
132 b20b42b8 2005-08-10 devnull 		fde->ref++;
133 b20b42b8 2005-08-10 devnull 		return 0;
134 b20b42b8 2005-08-10 devnull 	}
135 b20b42b8 2005-08-10 devnull 
136 b20b42b8 2005-08-10 devnull 	qlock(&fde->lock);
137 b20b42b8 2005-08-10 devnull 	fde->id = id;
138 b20b42b8 2005-08-10 devnull 	return 0;
139 b20b42b8 2005-08-10 devnull }
140 b20b42b8 2005-08-10 devnull 
141 b20b42b8 2005-08-10 devnull void
142 b20b42b8 2005-08-10 devnull _thread_fd_unlock(int fd, int type)
143 b20b42b8 2005-08-10 devnull {
144 b20b42b8 2005-08-10 devnull 	struct fd_entry *fde;
145 b20b42b8 2005-08-10 devnull 	int id;
146 b20b42b8 2005-08-10 devnull 
147 b20b42b8 2005-08-10 devnull 	fde = _thread_fd_lookup(fd);
148 b20b42b8 2005-08-10 devnull 	if(fde == nil) {
149 b20b42b8 2005-08-10 devnull 		fprint(2, "_thread_fd_unlock: fd %d not in table!\n", fd);
150 b20b42b8 2005-08-10 devnull 		return;
151 b20b42b8 2005-08-10 devnull 	}
152 b20b42b8 2005-08-10 devnull 
153 b20b42b8 2005-08-10 devnull 	if(type == FD_READ && --fde->rc >= 1)
154 b20b42b8 2005-08-10 devnull 		return;
155 b20b42b8 2005-08-10 devnull 	else
156 b20b42b8 2005-08-10 devnull 		fde->wc--;
157 b20b42b8 2005-08-10 devnull 
158 b20b42b8 2005-08-10 devnull 	id = proc()->osprocid;
159 b20b42b8 2005-08-10 devnull 	if(id == fde->id && fde->ref > 0) {
160 b20b42b8 2005-08-10 devnull 		fde->ref--;
161 b20b42b8 2005-08-10 devnull 		return;
162 b20b42b8 2005-08-10 devnull 	}
163 b20b42b8 2005-08-10 devnull 	fde->id = 0;
164 b20b42b8 2005-08-10 devnull 	qunlock(&fde->lock);
165 b20b42b8 2005-08-10 devnull }
166 b20b42b8 2005-08-10 devnull 
167 b20b42b8 2005-08-10 devnull void
168 b20b42b8 2005-08-10 devnull _thread_dl_lock(int t)
169 b20b42b8 2005-08-10 devnull {
170 b20b42b8 2005-08-10 devnull 	if(t)
171 b20b42b8 2005-08-10 devnull 		_spinunlock(&dl_lock);
172 b20b42b8 2005-08-10 devnull 	else
173 b20b42b8 2005-08-10 devnull 		_spinlock(&dl_lock);
174 b20b42b8 2005-08-10 devnull }
175 b20b42b8 2005-08-10 devnull 
176 b20b42b8 2005-08-10 devnull void
177 b20b42b8 2005-08-10 devnull _pthreadinit(void)
178 b20b42b8 2005-08-10 devnull {
179 b20b42b8 2005-08-10 devnull 	__isthreaded = 1;
180 b20b42b8 2005-08-10 devnull 	dlctl(nil, DL_SETTHREADLCK, _thread_dl_lock);
181 b20b42b8 2005-08-10 devnull 	signal(SIGUSR2, sigusr2handler);
182 b20b42b8 2005-08-10 devnull }