plan9front/sys/src/libbio/binit.c

183 lines
2.6 KiB
C

#include <u.h>
#include <libc.h>
#include <bio.h>
static Biobufhdr* wbufs[20];
static int atexitflag;
static
void
batexit(void)
{
Biobufhdr *bp;
int i;
for(i=0; i<nelem(wbufs); i++) {
bp = wbufs[i];
if(bp != 0) {
wbufs[i] = 0;
Bflush(bp);
}
}
}
static
void
deinstall(Biobufhdr *bp)
{
int i;
for(i=0; i<nelem(wbufs); i++)
if(wbufs[i] == bp)
wbufs[i] = 0;
}
static
void
install(Biobufhdr *bp)
{
int i;
deinstall(bp);
for(i=0; i<nelem(wbufs); i++)
if(wbufs[i] == 0) {
wbufs[i] = bp;
break;
}
if(atexitflag == 0) {
atexitflag = 1;
atexit(batexit);
}
}
static int
bioread(Biobufhdr *bp, void *v, long n)
{
return read(bp->fid, v, n);
}
static int
biowrite(Biobufhdr *bp, void *v, long n)
{
return write(bp->fid, v, n);
}
int
Binits(Biobufhdr *bp, int f, int mode, uchar *p, int size)
{
p += Bungetsize; /* make room for Bungets */
size -= Bungetsize;
switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
default:
fprint(2, "Binits: unknown mode %d\n", mode);
return Beof;
case OREAD:
bp->state = Bractive;
bp->ocount = 0;
bp->iof = bioread;
break;
case OWRITE:
install(bp);
bp->state = Bwactive;
bp->ocount = -size;
bp->iof = biowrite;
break;
}
bp->bbuf = p;
bp->ebuf = p+size;
bp->bsize = size;
bp->icount = 0;
bp->gbuf = bp->ebuf;
bp->fid = f;
bp->flag = 0;
bp->rdline = 0;
bp->offset = 0;
bp->runesize = 0;
bp->errorf = nil;
return 0;
}
int
Binit(Biobuf *bp, int f, int mode)
{
return Binits(bp, f, mode, bp->b, sizeof(bp->b));
}
Biobuf*
Bfdopen(int fd, int mode)
{
Biobuf *bp;
bp = malloc(sizeof(Biobuf));
if(bp == nil)
return nil;
if(Binits(bp, fd, mode, bp->b, sizeof(bp->b)) != 0){
free(bp);
return nil;
}
bp->flag = Bmagic; /* mark bp open & malloced */
setmalloctag(bp, getcallerpc(&fd));
return bp;
}
Biobuf*
Bopen(char *name, int mode)
{
Biobuf *bp;
int fd;
switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
default:
fprint(2, "Bopen: unknown mode %#x\n", mode);
return nil;
case OREAD:
fd = open(name, mode);
break;
case OWRITE:
fd = create(name, mode, 0666);
break;
}
if(fd < 0)
return nil;
bp = Bfdopen(fd, mode);
if(bp == nil){
close(fd);
return nil;
}
setmalloctag(bp, getcallerpc(&name));
return bp;
}
int
Bterm(Biobufhdr *bp)
{
int r;
deinstall(bp);
r = Bflush(bp);
if(bp->flag == Bmagic) {
bp->flag = 0;
close(bp->fid);
bp->fid = -1; /* prevent accidents */
free(bp);
}
/* otherwise opened with Binit(s) */
return r;
}
void
Biofn(Biobufhdr *bp, int (*f)(Biobufhdr *, void *, long))
{
if(f == nil)
if(bp->state == Bwactive)
bp->iof = biowrite;
else
bp->iof = bioread;
else
bp->iof = f;
}