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PDP-10 Archives
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SRI_NIC_PERM_FS_1_19910112
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kcc-4/lib/usys/write.c
There are 9 other files named write.c in the archive. Click here to see a list.
/*
* WRITE - URT low-level I/O write
*
* Copyright (C) 1986 by Ian Macky, SRI International
*/
#include "c-env.h"
#include "sys/usysio.h"
#include "sys/usysig.h"
#include "errno.h"
#if SYS_T20
#include "jsys.h"
#endif
static int outsys();
int
write(fd, buf, nbytes)
register int fd, nbytes;
register char *buf;
{
register int ufx, n, i;
register char *cp;
char *bufp;
char cbuf[UIO_BUFSIZ]; /* Temporary conversion buffer on stack */
int ncvt;
USYS_BEG();
if (fd < 0 || fd >= OPEN_MAX || !(ufx = _uioufx[fd]))
USYS_RETERR(EBADF);
if (nbytes == 0)
USYS_RET(0);
if (nbytes < 0)
USYS_RETERR(EINVAL);
/* Check for and handle unconverted case */
if (!(_uioflgs[ufx] & _UIO_CONVERTED)) {
for (;;) { /* Loop for interrupt continuation */
if ((n = outsys(ufx, buf, nbytes)) > 0)
USYS_RET(n); /* Normally wins */
if (n == 0) /* Failed? */
USYS_RETERR(EIO);
/* Interrupted. n has negative of # bytes left to write. */
if (USYS_END() < 0) { /* Allow ints, see if handler done */
errno = EINTR; /* Yeah, fail this way */
return nbytes + n; /* Return # of bytes written. */
}
/* Can proceed from interrupt! Update things... */
USYS_BEG(); /* Disable interrupts again */
if (ufx != _uioufx[fd]) /* Ensure FD still OK */
USYS_RETERR(EIO); /* Fail if switcheroo happened */
buf += nbytes + n; /* Update pointer by # bytes written */
nbytes = -n; /* Set new # bytes to write */
}
}
/* Handle converted case */
ncvt = nbytes; /* Get # bytes to convert */
bufp = cbuf-1; /* Use temporary conversion buffer on stack */
--buf;
while (ncvt > 0) {
register char *cp;
if (ncvt < (UIO_BUFSIZ/2)) /* Find # to cvt this pass */
n = ncvt;
else n = UIO_BUFSIZ/2;
ncvt -= n;
cp = bufp;
do {
if ((*++cp = *++buf) == '\n') { /* Copy bytes - if see LF, */
*cp = '\r'; /* replace with CR */
*++cp = '\n'; /* and add LF */
}
} while (--n > 0);
/* Now find # bytes converted and actually output them. */
i = cp - bufp;
cp = bufp+1;
for (;;) { /* Permit loop for interrupt continuation */
if ((n = outsys(ufx, cp, i)) > 0)
break; /* Normally we win... */
if (n == 0) {
USYS_RET(-1); /* Fail. Don't bother with # bytes. */
}
/* Interrupted! n has negative # bytes left to write. */
if (USYS_END() < 0) { /* Allow ints, see if must fail */
errno = EINTR; /* Yeah, fail this way */
return -1;
}
/* Can proceed from interrupt! Update things... */
USYS_BEG(); /* Disable interrupts again */
if (ufx != _uioufx[fd]) /* Ensure FD still OK */
USYS_RETERR(EIO); /* Fail if switcheroo happened */
cp += i + n; /* Update pointer by # bytes written */
i = -n; /* Set new # bytes to write */
} /* And continue loop to re-try call! */
}
USYS_RET(nbytes); /* Return # bytes */
}
/* outsys(ufx, buf, nbytes) - system-dependent output
** Returns:
** > 0 Won, return value is # of bytes written.
** = 0 Failed.
** < 0 Interrupted; value is -<# of bytes LEFT to be written>.
** In all cases, _uiopos is updated to reflect
** any bytes that were actually written.
*/
static int
outsys(ufx, buf, nbytes)
int ufx, nbytes;
char *buf;
{
#if SYS_10X+SYS_T20
int i, num, ablock[5];
switch (_uiotype[ufx]) {
case _DVDSK:
num = SOUT; /* Not interruptible */
break;
case _DVTTY:
case _DVPTY:
default:
num = SOUT | JSYS_OKINT; /* Allow interrupts */
break;
case _DVTCP: /* SOUTR to Force output */
num = SOUTR | JSYS_OKINT;
break;
}
ablock[1] = _uioch[ufx]; /* JFN */
ablock[2] = (int) (buf - 1); /* 1 before buffer */
ablock[3] = -nbytes; /* -# bytes to write */
num = jsys(num, ablock);
/* Now update vars */
_uiopos[ufx] += (i = nbytes + ablock[3]); /* Find # bytes written */
if (num > 0) /* SOUT succeeded? */
return i; /* Yes, all's well (probably) */
else if (num < 0) /* Interrupted? */
return (ablock[3] < 0 ? /* Yes, see if anything left to write */
ablock[3] : i); /* return -N if so, else claim we won. */
errno = EIO; /* SOUT failed somehow */
return 0;
#elif SYS_ITS
#asm
%chrbp 2,-2(17) /* Get buffer ptr */
skipg 3,-3(17) /* Get count */
jrst outsy9 /* No count */
skipge 1,-1(17) /* Get UFX */
jrst outsy9
.call [ setz
sixbit /siot/
.uioch(1) /* Channel # from table */
2 /* Byte ptr to source */
setz 3] /* Count of bytes */
jrst outsy9 /* Failed */
skipa 1,-1(17)
outsy9: tdza 1,1 /* Return 0 for failure */
sub 1,3 /* Return # bytes read/written */
#else
#error write() not supported for this system.
#endif
}
#if 0 /* OLD STUFF */
#if SYS_WAITS
/* --------------- */
/* write */
/* --------------- */
write(f,buf,n)
char *buf;
{
int chan;
int i;
char *c;
struct bufhead *p;
if ((chan=_uioch[f]) < 1 || n <= 0) return -1; /* find output channel */
if (chan == 1) { /* tty output? */
for (i = n; i-- ; ) _putty(*buf++); /* yes, one char at a time */
return n; /* return the count */
}
p = &buffers[chan]; /* other output, get buffer */
c = p->user; /* user deposit pointer */
i = p->count; /* number of chars in buffer */
while (n--) { /* for all chars in buffer */
*++c = *buf++; /* drop next char in */
if (--i <= 0) { /* if no more room */
if (!_out(chan)) return -1; /* send the buffer out */
c = p->user; /* get new deposit pointer */
i = p->count; /* and count */
}
}
p->user = c; /* save updated deposit pointer */
p->count = i; /* and buffer space count */
return n; /* return the number of chars sent */
}
/* -------------------- */
/* byte write */
/* -------------------- */
bwrite(f,buf,n)
char *buf;
{
int chan;
int i,save;
char *c;
struct bufhead *p;
if ((chan=_uioch[f]) < 1 || n < 0) return -1;
if (chan == 1) { /* tty output? */
for (i = n; i-- ; ) _putty(*buf++); /* yes, do char at a time */
return n; /* and return count */
}
p = &buffers[chan]; /* normal output, find buffer */
save = p->user; /* and pointer */
save++;
c = (save & 0777777) | (0341000<<18); /* turn into 8-bit byte pointer */
c--;
i = p->count*4; /* get number of bytes avail */
while (n--) { /* while still things to do */
*++c = *buf++; /* add char to buffer */
if (--i <= 0) { /* if space in buffer gone */
if (!_out(chan)) return -1; /* send it off */
save = p->user; /* refill buffer */
c = (save & 0777777) | (0341000<<18); /* make pointer again */
i = p->count*4; /* and fix up count */
}
}
chan = c; /* get final word */
p->user = (chan & 0777777) | (save & (0777777<<18)); /* as 8-bit ptr */
p->count = i/4; /* fix count */
return n; /* all done */
}
/* -------------------------- */
/* image mode write */
/* -------------------------- */
iwrite(f,buf,n)
char *buf;
{
int chan;
int i,save;
char *c;
struct bufhead *p;
if ((chan=_uioch[f]) < 1 || n < 0) return -1;
if (chan == 1) { /* tty output? */
for (i = n; i-- ; ) _putty(*buf++); /* yes, send one by one */
return n; /* and return count */
}
p = &buffers[chan]; /* get buffer */
c = p->user; /* and buffer pointer */
i = p->count; /* and buffer space count */
while (n--) { /* while bytes to send */
*++c = *buf++; /* send one */
if (--i <= 0) { /* if out of room */
if (!_out(chan)) return -1; /* send buffer off */
}
}
p->count = i; /* put back count */
p->user = c; /* and deposit pointer */
return n; /* return number of bytes sent */
}
static _putty(), _out();
#asm
; ************************************************************
; output a character to the tty
; ************************************************************
;
.PUTTY: MOVE 1,-1(17)
OUTCHR 1
POPJ 17,
; ************************************************************
; output buffer (chan #, bufptr)
; ************************************************************
;
.OUT: MOVE 1,-1(17)
ANDI 1,17
LSH 1,27 ; shift channel # into ac field
IOR 1,[OUT 0,0]
MOVEM 1,.+1
OUT 0,0
JRST $RETT ; no error
JRST $RETF ; error
#endasm
#endif /* WAITS */
#endif /* Commented-out stuff */