1 b2cfc4e2 2003-09-30 devnull .TH IOPROC 2
  2 b2cfc4e2 2003-09-30 devnull .SH NAME
  3 b2cfc4e2 2003-09-30 devnull closeioproc,
  4 b2cfc4e2 2003-09-30 devnull iocall,
  5 b2cfc4e2 2003-09-30 devnull ioclose,
  6 b2cfc4e2 2003-09-30 devnull iointerrupt,
  7 b2cfc4e2 2003-09-30 devnull iodial,
  8 b2cfc4e2 2003-09-30 devnull ioopen,
  9 b2cfc4e2 2003-09-30 devnull ioproc,
 10 b2cfc4e2 2003-09-30 devnull ioread,
 11 b2cfc4e2 2003-09-30 devnull ioreadn,
 12 b2cfc4e2 2003-09-30 devnull iowrite \- slave I/O processes for threaded programs
 13 b2cfc4e2 2003-09-30 devnull .SH SYNOPSIS
 14 b2cfc4e2 2003-09-30 devnull .PP
 15 b2cfc4e2 2003-09-30 devnull .de XX
 16 b2cfc4e2 2003-09-30 devnull .ift .sp 0.5
 17 b2cfc4e2 2003-09-30 devnull .ifn .sp
 18 b2cfc4e2 2003-09-30 devnull ..
 19 b2cfc4e2 2003-09-30 devnull .EX
 20 b2cfc4e2 2003-09-30 devnull .ta \w'Ioproc* 'u
 21 b2cfc4e2 2003-09-30 devnull #include <u.h>
 22 b2cfc4e2 2003-09-30 devnull #include <libc.h>
 23 b2cfc4e2 2003-09-30 devnull #include <thread.h>
 24 b2cfc4e2 2003-09-30 devnull .sp
 25 b2cfc4e2 2003-09-30 devnull typedef struct Ioproc Ioproc;
 26 b2cfc4e2 2003-09-30 devnull .sp
 27 b2cfc4e2 2003-09-30 devnull Ioproc*	ioproc(void);
 28 b2cfc4e2 2003-09-30 devnull .XX
 29 b2cfc4e2 2003-09-30 devnull int	ioopen(Ioproc *io, char *file, int omode);
 30 b2cfc4e2 2003-09-30 devnull int	ioclose(Ioproc *io, int fd);
 31 b2cfc4e2 2003-09-30 devnull long	ioread(Ioproc *io, int fd, void *a, long n);
 32 b2cfc4e2 2003-09-30 devnull long	ioreadn(Ioproc *io, int fd, void *a, long n);
 33 b2cfc4e2 2003-09-30 devnull long	iowrite(Ioproc *io, int fd, void *a, long n);
 34 b2cfc4e2 2003-09-30 devnull int	iodial(Ioproc *io, char *addr, char *local, char *dir, char *cdfp);
 35 b2cfc4e2 2003-09-30 devnull .XX
 36 b2cfc4e2 2003-09-30 devnull void	iointerrupt(Ioproc *io);
 37 b2cfc4e2 2003-09-30 devnull void	closeioproc(Ioproc *io);
 38 b2cfc4e2 2003-09-30 devnull .XX
 39 b2cfc4e2 2003-09-30 devnull long	iocall(Ioproc *io, long (*op)(va_list *arg), ...);
 40 b2cfc4e2 2003-09-30 devnull .EE
 41 b2cfc4e2 2003-09-30 devnull .SH DESCRIPTION
 42 b2cfc4e2 2003-09-30 devnull .PP
 43 b2cfc4e2 2003-09-30 devnull These routines provide access to I/O in slave procs.
 44 b2cfc4e2 2003-09-30 devnull Since the I/O itself is done in a slave proc, other threads
 45 b2cfc4e2 2003-09-30 devnull in the calling proc can run while the calling thread
 46 b2cfc4e2 2003-09-30 devnull waits for the I/O to complete.
 47 b2cfc4e2 2003-09-30 devnull .PP
 48 b2cfc4e2 2003-09-30 devnull .I Ioproc
 49 b2cfc4e2 2003-09-30 devnull forks a new slave proc and returns a pointer to the
 50 b2cfc4e2 2003-09-30 devnull .B Ioproc
 51 b2cfc4e2 2003-09-30 devnull associated with it.
 52 b2cfc4e2 2003-09-30 devnull .I Ioproc
 53 b2cfc4e2 2003-09-30 devnull uses
 54 b2cfc4e2 2003-09-30 devnull .I mallocz
 55 b2cfc4e2 2003-09-30 devnull and
 56 b2cfc4e2 2003-09-30 devnull .IR proccreate ;
 57 b2cfc4e2 2003-09-30 devnull if either fails, it calls
 58 b2cfc4e2 2003-09-30 devnull .I sysfatal
 59 b2cfc4e2 2003-09-30 devnull rather than return an error.
 60 b2cfc4e2 2003-09-30 devnull .PP
 61 b2cfc4e2 2003-09-30 devnull .IR Ioopen ,
 62 b2cfc4e2 2003-09-30 devnull .IR ioclose ,
 63 b2cfc4e2 2003-09-30 devnull .IR ioread ,
 64 b2cfc4e2 2003-09-30 devnull .IR ioreadn ,
 65 b2cfc4e2 2003-09-30 devnull .IR iowrite ,
 66 b2cfc4e2 2003-09-30 devnull and
 67 b2cfc4e2 2003-09-30 devnull .IR iodial
 68 b2cfc4e2 2003-09-30 devnull are execute the
 69 b2cfc4e2 2003-09-30 devnull similarly named library or system calls
 70 b2cfc4e2 2003-09-30 devnull (see
 71 b2cfc4e2 2003-09-30 devnull .IR open (2),
 72 b2cfc4e2 2003-09-30 devnull .IR read (2),
 73 b2cfc4e2 2003-09-30 devnull and
 74 b2cfc4e2 2003-09-30 devnull .IR dial (2))
 75 b2cfc4e2 2003-09-30 devnull in the slave process associated with
 76 b2cfc4e2 2003-09-30 devnull .IR io .
 77 b2cfc4e2 2003-09-30 devnull It is an error to execute more than one call
 78 b2cfc4e2 2003-09-30 devnull at a time in an I/O proc.
 79 b2cfc4e2 2003-09-30 devnull .PP
 80 b2cfc4e2 2003-09-30 devnull .I Iointerrupt
 81 b2cfc4e2 2003-09-30 devnull interrupts the call currently executing in the I/O proc.
 82 b2cfc4e2 2003-09-30 devnull If no call is executing,
 83 b2cfc4e2 2003-09-30 devnull .IR iointerrupt
 84 b2cfc4e2 2003-09-30 devnull is a no-op.
 85 b2cfc4e2 2003-09-30 devnull .PP
 86 b2cfc4e2 2003-09-30 devnull .I Closeioproc
 87 b2cfc4e2 2003-09-30 devnull terminates the I/O proc and frees the associated
 88 b2cfc4e2 2003-09-30 devnull .B Ioproc .
 89 b2cfc4e2 2003-09-30 devnull .PP
 90 b2cfc4e2 2003-09-30 devnull .I Iocall
 91 b2cfc4e2 2003-09-30 devnull is a primitive that may be used to implement
 92 b2cfc4e2 2003-09-30 devnull more slave I/O routines.
 93 b2cfc4e2 2003-09-30 devnull .I Iocall
 94 b2cfc4e2 2003-09-30 devnull arranges for
 95 b2cfc4e2 2003-09-30 devnull .I op
 96 b2cfc4e2 2003-09-30 devnull to be called in
 97 b2cfc4e2 2003-09-30 devnull .IR io 's
 98 b2cfc4e2 2003-09-30 devnull proc, with
 99 b2cfc4e2 2003-09-30 devnull .I arg
100 b2cfc4e2 2003-09-30 devnull set to the variable parameter list,
101 b2cfc4e2 2003-09-30 devnull returning the value that
102 b2cfc4e2 2003-09-30 devnull .I op
103 b2cfc4e2 2003-09-30 devnull returns.
104 b2cfc4e2 2003-09-30 devnull .SH EXAMPLE
105 b2cfc4e2 2003-09-30 devnull Relay messages between two file descriptors,
106 b2cfc4e2 2003-09-30 devnull counting the total number of bytes seen:
107 b2cfc4e2 2003-09-30 devnull .IP
108 b2cfc4e2 2003-09-30 devnull .EX
109 b2cfc4e2 2003-09-30 devnull .ta +\w'xxxx'u +\w'xxxx'u +\w'xxxx'u
110 b2cfc4e2 2003-09-30 devnull int tot;
111 b2cfc4e2 2003-09-30 devnull 
112 b2cfc4e2 2003-09-30 devnull void
113 b2cfc4e2 2003-09-30 devnull relaythread(void *v)
114 b2cfc4e2 2003-09-30 devnull {
115 b2cfc4e2 2003-09-30 devnull 	int *fd, n;
116 b2cfc4e2 2003-09-30 devnull 	char buf[1024];
117 b2cfc4e2 2003-09-30 devnull 	Ioproc *io;
118 b2cfc4e2 2003-09-30 devnull 
119 b2cfc4e2 2003-09-30 devnull 	fd = v;
120 b2cfc4e2 2003-09-30 devnull 	io = ioproc();
121 b2cfc4e2 2003-09-30 devnull 	while((n = ioread(io, fd[0], buf, sizeof buf)) > 0){
122 b2cfc4e2 2003-09-30 devnull 		if(iowrite(io, fd[1], buf, n) != n)
123 b2cfc4e2 2003-09-30 devnull 			sysfatal("iowrite: %r");
124 b2cfc4e2 2003-09-30 devnull 		tot += n;
125 b2cfc4e2 2003-09-30 devnull 	}
126 b2cfc4e2 2003-09-30 devnull 	closeioproc(io);
127 b2cfc4e2 2003-09-30 devnull }
128 b2cfc4e2 2003-09-30 devnull 
129 b2cfc4e2 2003-09-30 devnull void
130 b2cfc4e2 2003-09-30 devnull relay(int fd0, int fd1)
131 b2cfc4e2 2003-09-30 devnull {
132 b2cfc4e2 2003-09-30 devnull 	int fd[4];
133 b2cfc4e2 2003-09-30 devnull 
134 b2cfc4e2 2003-09-30 devnull 	fd[0] = fd[3] = fd0;
135 b2cfc4e2 2003-09-30 devnull 	fd[1] = fd[2] = fd1;
136 b2cfc4e2 2003-09-30 devnull 	threadcreate(relaythread, fd, 8192);
137 b2cfc4e2 2003-09-30 devnull 	threadcreate(relaythread, fd+2, 8192);
138 b2cfc4e2 2003-09-30 devnull }
139 b2cfc4e2 2003-09-30 devnull .EE
140 b2cfc4e2 2003-09-30 devnull .LP
141 b2cfc4e2 2003-09-30 devnull If the two
142 b2cfc4e2 2003-09-30 devnull .I relaythread
143 b2cfc4e2 2003-09-30 devnull instances were running in different procs, the
144 b2cfc4e2 2003-09-30 devnull common access to
145 b2cfc4e2 2003-09-30 devnull .I tot
146 b2cfc4e2 2003-09-30 devnull would be unsafe.
147 b2cfc4e2 2003-09-30 devnull .EE
148 b2cfc4e2 2003-09-30 devnull .PP
149 b2cfc4e2 2003-09-30 devnull Implement
150 b2cfc4e2 2003-09-30 devnull .IR ioread :
151 b2cfc4e2 2003-09-30 devnull .IP
152 b2cfc4e2 2003-09-30 devnull .EX
153 b2cfc4e2 2003-09-30 devnull static long
154 b2cfc4e2 2003-09-30 devnull _ioread(va_list *arg)
155 b2cfc4e2 2003-09-30 devnull {
156 b2cfc4e2 2003-09-30 devnull 	int fd;
157 b2cfc4e2 2003-09-30 devnull 	void *a;
158 b2cfc4e2 2003-09-30 devnull 	long n;
159 b2cfc4e2 2003-09-30 devnull 
160 b2cfc4e2 2003-09-30 devnull 	fd = va_arg(*arg, int);
161 b2cfc4e2 2003-09-30 devnull 	a = va_arg(*arg, void*);
162 b2cfc4e2 2003-09-30 devnull 	n = va_arg(*arg, long);
163 b2cfc4e2 2003-09-30 devnull 	return read(fd, a, n);
164 b2cfc4e2 2003-09-30 devnull }
165 b2cfc4e2 2003-09-30 devnull 
166 b2cfc4e2 2003-09-30 devnull long
167 b2cfc4e2 2003-09-30 devnull ioread(Ioproc *io, int fd, void *a, long n)
168 b2cfc4e2 2003-09-30 devnull {
169 b2cfc4e2 2003-09-30 devnull 	return iocall(io, _ioread, fd, a, n);
170 b2cfc4e2 2003-09-30 devnull }
171 b2cfc4e2 2003-09-30 devnull .EE
172 b2cfc4e2 2003-09-30 devnull .SH SOURCE
173 b2cfc4e2 2003-09-30 devnull .B /sys/src/libthread/io*.c
174 b2cfc4e2 2003-09-30 devnull .SH SEE ALSO
175 b2cfc4e2 2003-09-30 devnull .IR dial (2),
176 b2cfc4e2 2003-09-30 devnull .IR open (2),
177 b2cfc4e2 2003-09-30 devnull .IR read (2),
178 b2cfc4e2 2003-09-30 devnull .IR thread (2)
179 b2cfc4e2 2003-09-30 devnull